TY - THES A1 - Mußotter, Marlene T1 - On nation, homeland, and democracy: Toward a novel three-factor measurement model for nationalism and patriotism BT - revisiting the nationalism-patriotism distinction N2 - The nationalism-patriotism distinction is one of the most influential distinctions in the field of political psychology. While frequently used, the distinction suffers from a number of shortcomings that have hitherto been devoted little attention to. This dissertation aims to contribute to fill this research gap by systematically addressing these pitfalls. Notably, it does not abandon the binary distinction as such, but aims to further refine it. Thoroughly revisiting the nationalism-patriotism distinction, it synthesises the field's two predominant research traditions, i.e. the work of Kosterman and Feshbach (1989) in the U.S. and the one of Blank and Schmidt (2003) in Germany, that have not been brought into dialogue. In so doing, and engaging with research on attachment, it calls for a more nuanced triad of attachments: nationalism, that revolves around the nation; patriotism, that refers to the homeland; and democratic patriotism with democracy as its object of attachment. In line with this triad, it introduces a novel three-factor measurement model that has been validated in three studies in Germany. Overall, the dissertation underlines the need to approach ambiguous and complex concepts such as nationalism and patriotism in a more theoretically consistent way before operationalizing them in a rigorous manner. KW - Nationalismus KW - Patriotismus KW - Demokratie KW - Nation KW - Identität Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-13781 ER - TY - THES A1 - Fink, Simon Dominik T1 - Constrained Planarity Algorithms in Theory and Practice N2 - In the constrained planarity setting, we ask whether a graph admits a crossing-free drawing that additionally satisfies a given set of constraints. These constraints are often derived from very natural problems; prominent examples are Level Planarity, where vertices have to lie on given horizontal lines indicating a hierarchy, Partially Embedded Planarity, where we extend a given drawing without modifying already-drawn parts, and Clustered Planarity, where we additionally draw the boundaries of clusters which recursively group the vertices in a crossing-free manner. In the last years, the family of constrained planarity problems received a lot of attention in the field of graph drawing. Efficient algorithms were discovered for many of them, while a few others turned out to be NP-complete. In contrast to the extensive theoretical considerations and the direct motivation by applications, only very few of the found algorithms have been implemented and evaluated in practice. The goal of this thesis is to advance the research on both theoretical as well as practical aspects of constrained planarity. On the theoretical side, we consider two types of constrained planarity problems. The first type are problems that individually constrain the rotations of vertices, that is they restrict the counter-clockwise cyclic orders of the edges incident to vertices. We give a simple linear-time algorithm for the problem Partially Embedded Planarity, which also generalizes to further constrained planarity variants of this type. The second type of constrained planarity problem concerns more involved planarity variants that come down to the question whether there are embeddings of one or multiple graphs such that the rotations of certain vertices are in sync in a certain way. Clustered Planarity and a variant of the Simultaneous Embedding with Fixed Edges Problem (Connected SEFE-2) are well-known problems of this type. Both are generalized by our Synchronized Planarity problem, for which we give a quadratic algorithm. Through reductions from various other problems, we provide a unified modelling framework for almost all known efficiently solvable constrained planarity variants that also directly provides a quadratic-time solution to all of them. For both our algorithms, a key ingredient for reaching an efficient solution is the usage of the right data structure for the problem at hand. In this case, these data structures are the SPQR-tree and the PC-tree, which describe planar embedding possibilities from a global and a local perspective, respectively. More specifically, PC-trees can be used to locally describe the possible cyclic orders of edges around vertices in all planar embeddings of a graph. This makes it a key component for our algorithms, as it allows us to test planarity while also respecting further constraints, and to communicate constraints arising from the surrounding graph structure between vertices with synchronized rotation. Bridging over to the practical side, we present the first correct implementation of PC-trees. We also describe further improvements, which allow us to outperform all implementations of alternative data structures (out of which we only found very few to be fully correct) by at least a factor of 4. We show that this yields a simple and competitive planarity test that can also yield an embedding to certify planarity. We also use our PC-tree implementation to implement our quadratic algorithm for solving Synchronized Planarity. Here, we show that our algorithm greatly outperforms previous attempts at solving related problems like Clustered Planarity in practice. We also engineer its running time and show how degrees of freedom in the theoretical algorithm can be leveraged to yield an up to tenfold speed-up in practice. KW - Constrained Planarity KW - Clustered Planarity KW - Synchronized Planarity KW - Algorithm Engineering Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-13817 ER - TY - THES A1 - Danner, Dominik T1 - Towards Quality of Service and Fairness in Smart Grid Applications N2 - Due to the increasing amount of distributed renewable energy generation and the emerging high demand at consumer connection points, e. g., electric vehicles, the power distribution grid will reach its capacity limit at peak load times if it is not expensively enhanced. Alternatively, smart flexibility management that controls user assets can help to better utilize the existing power grid infrastructure for example by sharing available grid capacity among connected electric vehicles or by disaggregating flexibility requests to hybrid photovoltaic battery energy storage systems in households. Besides maintaining an acceptable state of the power distribution grid, these smart grid applications also need to ensure a certain quality of service and provide fairness between the individual participants, both of which are not extensively discussed in the literature. This thesis investigates two smart grid applications, namely electric vehicle charging-as-a-service and flexibility-provision-as-a-service from distributed energy storage systems in private households. The electric vehicle charging service allocation is modeled with distributed queuing-based allocation mechanisms which are compared to new probabilistic algorithms. Both integrate user constraints (arrival time, departure time, and energy required) to manage the quality of service and fairness. In the queuing-based allocation mechanisms, electric vehicle charging requests are packetized into logical charging current packets, representing the smallest controllable size of the charging process. These packets are queued at hierarchically distributed schedulers, which allocate the available charging capacity using the time and frequency division multiplexing technique known from the networking domain. This allows multiple electric vehicles to be charged simultaneously with variable charging currents. To achieve high quality of service and fairness among electric vehicle charging processes, dynamic weights are introduced into a weighted fair queuing scheduler that considers electric vehicle departure time and required energy for prioritization. The distributed probabilistic algorithms are inspired by medium access protocols from computer networking, such as binary exponential backoff, and control the quality of service and fairness by adjusting sampling windows and waiting periods based on user requirements. The second smart grid application under investigation aims to provide flexibility provision-as-a-service that disaggregates power flexibility requests to distributed battery energy storage systems in private households. Commonly, the main purpose of stationary energy storage is to store energy from a local photovoltaic system for later use, e. g., for overnight charging of an electric vehicle. This is optimized locally by a home energy management system, which also allows the scheduling of external flexibility requests defined by the deviation from the optimal power profile at the grid connection point, for example, to perform peak shaving at the transformer. This thesis discusses a linear heuristic and a meta heuristic to disaggregate a flexibility request to the single participating energy management systems that are grouped into a flexibility pool. Thereby, the linear heuristic iteratively assigns portions of the power flexibility to the most appropriate energy management system for one time slot after another, minimizing the total flexibility cost or maximizing the probability of flexibility delivery. In addition, a multi-objective genetic algorithm is proposed that also takes into account power grid aspects, quality of service, and fairness among par-ticipating households. The genetic operators are tailored to the flexibility disaggregation search space, taking into account flexibility and energy management system constraints, and enable power-optimized buffering of fitness values. Both smart grid applications are validated on a realistic power distribution grid with real driving patterns and energy profiles for photovoltaic generation and household consumption. The results of all proposed algorithms are analyzed with respect to a set of newly defined metrics on quality of service, fairness, efficiency, and utilization of the power distribution grid. One of the main findings is that none of the tested algorithms outperforms the others in all quality of service metrics, however, integration of user expectations improves the service quality compared to simpler approaches. Furthermore, smart grid control that incorporates users and their flexibility allows the integration of high-load applications such as electric vehicle charging and flexibility aggregation from distributed energy storage systems into the existing electricity distribution infrastructure. However, there is a trade-off between power grid aspects, e. g., grid losses and voltage values, and the quality of service provided. Whenever active user interaction is required, means of controlling the quality of service of users’ smart grid applications are necessary to ensure user satisfaction with the services provided. Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-13731 ER - TY - THES A1 - Grösbrink, Carl-Friederich T1 - Three Essays on Firm Value and Firm Risk and their Relation to IT-Exposure, Corporate Social Responsibility, and Religiosity N2 - 1. IT-Exposure and Firm Value: We analyze the joint influence of a firm’s information technology (IT)-Exposure and investment behavior on firm value. Estimating a firm’s (partial) IT-Exposure allows for distinguishing between firms with a business model that is challenged by IT above and below market average. Hence, we estimate the annual IT-Exposure of a firm using a 3-factor Fama-French model extended by an IT-proxy. Subsequently, we analyze the relationship with Tobin’s Q in a panel data context, accounting for the relationship between IT-Exposure and investments proxied by R&D as well as CapEx. We use more than 48,000 firm-year observations for firms in the Russell 3000 Index covering the period 1990 to 2018. Although IT-Exposure has a negative impact on firm value, this discount can be overcompensated by up to 2.1 times by sufficient investments through R&D and CapEx, giving a firm with an average Tobin’s Q a premium of 14.8% to 19.2%, while controlling for endogeneity. 2. Corporate Social Responsibility, Risk, and Firm Value: An Unconditional Quantile Regression Approach: This paper examines the impact of corporate social responsibility (CSR) on firm risk, comprising total risk, idiosyncratic risk, and systematic risk, as well as firm value. We focus on analyzing the interrelationships along the entire distribution of the dependent variables, thus estimating an unconditional quantile regression (UQR). The analysis is based on CSR scores from Refinitiv and MSCI, using up to 12,013 firm-year observations over the period 2002 to 2019 for all U.S. companies listed on NYSE, NASDAQ, and AMEX. UQR reveals strongly heterogeneous effects along the unconditional quantiles of the dependent variables, which are reflected in sign changes, magnitude and significance variations. For CSR we find a risk-reducing as well as value-enhancing effect. When applying fixed effects OLS, we can just partly confirm the risk-reducing and value-enhancing effect of CSR shown in the literature. 3. Heterogenous Effects of Religiosity on Firm Risk and Firm Value: An Unconditional Quantile Regression Approach: This paper examines the impact of religiosity on firm risk, comprising total risk, idiosyncratic risk, and systematic risk, as well as firm value. We focus on analyzing the interrelationships along the entire distribution of the dependent variables, thus estimating an unconditional quantile regression (UQR). The analysis is based on all U.S. companies listed on NYSE, NASDAQ, and AMEX for the period from 1980 through 2020. UQR reveals strongly heterogeneous effects along the unconditional quantiles of the dependent variables, which are reflected in sign changes, magnitude and significance variations. Overall, the risk-reducing effect of religiosity is more pronounced in the higher quantiles of the distribution. We further observe a value-reducing as well as value-enhancing religiosity effect. When applying fixed effects OLS, we can confirm the risk-reducing and non-existing value effect of religiosity shown in the literature. The robustness of our results is underpinned by a battery of additional tests. KW - Firm Value KW - Firm Risk KW - IT-Exposure KW - Corporate Social Responsibility KW - Religiosity Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-11558 ER - TY - THES A1 - Seruset, Marco T1 - Three Essays on Price Discovery, Stock Liquidity, and Crash Risk N2 - Abstract 1: This paper investigates whether market quality, uncertainty, investor sentiment and attention, and macroeconomic news affect bitcoin price discovery in spot and futures markets. Over the period December 2017 – March 2019, we find significant time variation in the contribution to price discovery of the two markets. Increases in price discovery are mainly driven by relative trading costs and volume, and by uncertainty to a lesser extent. Additionally, medium-sized trades contain most information in terms of price discovery. Finally, higher news-based bitcoin sentiment increases the informational role of the futures market, while attention and macroeconomic news have no impact on price discovery. Abstract 2: We investigate whether local religious norms affect stock liquidity for U.S. listed companies. Over the period 1997–2020, we find that firms located in more religious areas have higher liquidity, as reflected by lower bid-ask spreads. This result persists after the inclusion of additional controls, such as governance metrics, and further sensitivity and endogeneity analyses. Subsample tests indicate that the impact of religiosity on stock liquidity is particularly evident for firms operating in a poor information environment. We further show that firms located in more religious areas have lower price impact of trades and smaller probability of information-based trading. Overall, our findings are consistent with the notion that religiosity, with its antimanipulative ethos, probably fosters trust in corporate actions and information flows, especially when little is known about the firm. Finally, we conjecture an indirect firm value implication of religiosity through the channel of stock liquidity. Abstract 3: This study shows that higher physical distance to institutional shareholders is associated with higher stock price crash risk. Since monitoring costs increase with distance, the results are consistent with the monitoring theory of local institutional investors. Cross-sectional analyses show that the effect of proximity on crash risk is more pronounced for firms with weak internal governance structures. The significant relation between distance and crash risk still holds under the implementation of the Sarbanes-Oxley Act, however, to a lower extent. Also, the existence of the channel of bad news hoarding is confirmed. Finally, I show that there is heterogeneity in distance-induced monitoring activities of different types of institutions. Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-11563 ER - TY - THES A1 - Maimunah, Siti T1 - Reclaiming "Tubuh-Tanah Air": A Life Project on Doing Feminist Political Ecology at the Capitalist Frontier N2 - My study examines how the configuration of the capitalist frontier through extractivism shapes ethnicity, gender, and intersectionality in the areas surrounding a nickel mine in Sorowako (East Luwu District, South Sulawesi), logging and coal mining along the Lalang River (Murung Raya District, Central Kalimantan) Indonesia. The colonial frontier intersects with the capitalist frontier and provides the circumstances for its formation. The colonial restrictions, religions, commodities, the imposition of labor discipline, and political changes have molded ethnic identities and relationships with nature. Furthermore, using autoethnography and Feminist Political Ecology, I combine my experiences as a woman academic-activist with the experiences of the people in my research area. I identify how communities and individuals interact with the multiple-frontier in everyday life by defining the configuration of the frontier from above and below. Thus, my dissertation contributes to understanding how I, the community, and the capitalist frontier landscape are contained and can potentially transform into multidimensional resistance. I develop a link between the body as the interior frontier and the extractive landscape to be transformed into a perspective of “Tubuh-tanah air” as a future arena of engagement and resistance to extractivism. KW - Extractivism KW - Capitalist frontier KW - Feminist Political Ecology KW - Resistance KW - Tubuh-tanah air Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-11656 ER - TY - THES A1 - McLarren, Katharina T1 - Religion and International Society - Approaches to Including Religion in the International Relations Research Agenda N2 - Religion can unite and divide, it can lead to a strengthening or a weakening of identity and legitimacy. Religion can stoke conflicts but it can also pacify them – within societies and in international politics. Religion endures and it can exist independently of states, it can constitute them, and it can provide new forms of states, societies, and empires. Arguably, religion shapes or even constitutes the international society of states, an aspect so far neglected in the field of International Relations. The dissertation provides a new definition of religion for International Relations and the English School in particular. Based upon this understanding of religion, the five publications presented in the dissertation provide new analytical and theoretical concepts and approaches to fill the research gap. Religion is integrated into the theoretical framework of the English School in the form of a “prime institution” and with the help of the “quilt model”. While the former expands the theoretical framework, the latter adds an analytical layer. Based upon this definition religion is also introduced as a concept (“hybrid actorness”) in Foreign Policy Analysis, opening it up to become less state-centrist and more transnational-oriented, thereby boosting its relevance considering the evolving international (global) society. In another step, the Securitization framework of analysis is expanded to include (freedom) of religion. By revisiting the publications, the dissertation is able to identify next steps in terms of avenues of research. Finally, the dissertation reveals areas of study which contribute to increasing the pertinence of IR, particularly of the English School. KW - Religion KW - International Society KW - English School Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-12365 ER - TY - JOUR A1 - Caspari-Sadeghi, Sima T1 - Learning assessment in the age of big data: Learning analytics in higher education JF - Cogent Education N2 - Data-driven decision-making and data-intensive research are becoming prevalent in many sectors of modern society, i.e. healthcare, politics, business, and entertainment. During the COVID-19 pandemic, huge amounts of educational data and new types of evidence were generated through various online platforms, digital tools, and communication applications. Meanwhile, it is acknowledged that educa-tion lacks computational infrastructure and human capacity to fully exploit the potential of big data. This paper explores the use of Learning Analytics (LA) in higher education for measurement purposes. Four main LA functions in the assessment are outlined: (a) monitoring and analysis, (b) automated feedback, (c) prediction, prevention, and intervention, and (d) new forms of assessment. The paper con-cludes by discussing the challenges of adopting and upscaling LA as well as the implications for instructors in higher education. KW - Big data KW - learning analytics KW - technology-enhanced assessment Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-12236 VL - 2023 IS - Volume 110, issue 1 PB - Taylor & Francis ER - TY - THES A1 - Duffourc, Mindy T1 - Liability for Negligent Healthcare Clinical Risk Management in the United States and Germany N2 - Systems-focused error prevention efforts are internationally recognized in the healthcare industry, and industry efforts to identify and correct organizational defects through the process of CRM are well established in the U.S. and Germany. However, in both countries, there is no clear corresponding liability for healthcare organizations who fail to engage in systems-based learning through the process of clinical risk management (CRM). Although both jurisdictions do recognize organization-based theories of liability, liability for negligent CRM has not been explicitly recognized by courts in either jurisdiction to date. German legal scholars, recognizing this gap in liability for healthcare organizations, have written in support of finding liability for negligent CRM under existing tort law; however, there is no corresponding discussion in the American legal literature. This dissertation fills that gap with a comparative analysis of medical negligence law in the U.S. and Germany through the international lens of modern medical error prevention science and policy to articulate a legal basis and sketch the evidentiary framework for tort liability based on negligent CRM. KW - law KW - law and medicine KW - medical liability KW - medical negligence KW - medical errors Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-13859 ER - TY - JOUR A1 - Herbold, Steffen A1 - Hautli‑Janisz, Annette A1 - Heuer, Ute A1 - Kikteva, Zlata A1 - Trautsch, Alexander T1 - A large‑scale comparison of human‑written versus ChatGPT‑generated essays JF - Scientific Reports N2 - ChatGPT and similar generative AI models have attracted hundreds of millions of users and have become part of the public discourse. Many believe that such models will disrupt society and lead to significant changes in the education system and information generation. So far, this belief is based on either colloquial evidence or benchmarks from the owners of the models—both lack scientific rigor. We systematically assess the quality of AI-generated content through a large-scale study comparing human-written versus ChatGPT-generated argumentative student essays. We use essays that were rated by a large number of human experts (teachers). We augment the analysis by considering a set of linguistic characteristics of the generated essays. Our results demonstrate that ChatGPT generates essays that are rated higher regarding quality than human-written essays. The writing style of the AI models exhibits linguistic characteristics that are different from those of the human-written essays. Since the technology is readily available, we believe that educators must act immediately. We must re-invent homework and develop teaching concepts that utilize these AI models in the same way as math utilizes the calculator: teach the general concepts first and then use AI tools to free up time for other learning objectives. Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-13961 VL - 13 PB - Springer Nature ER - TY - JOUR A1 - Hassen, Wiem Fekih A1 - Ben Ahmed, Mariem T1 - Optimization of a Redox-Flow Battery Simulation Model Based on a Deep Reinforcement Learning Approach JF - Batteries N2 - Vanadium redox-flow batteries (VRFBs) have played a significant role in hybrid energy storage systems (HESSs) over the last few decades owing to their unique characteristics and advantages. Hence, the accurate estimation of the VRFB model holds significant importance in large-scale storage applications, as they are indispensable for incorporating the distinctive features of energy storage systems and control algorithms within embedded energy architectures. In this work, we propose a novel approach that combines model-based and data-driven techniques to predict battery state variables, i.e., the state of charge (SoC), voltage, and current. Our proposal leverages enhanced deep reinforcement learning techniques, specifically deep q-learning (DQN), by combining q-learning with neural networks to optimize the VRFB-specific parameters, ensuring a robust fit between the real and simulated data. Our proposed method outperforms the existing approach in voltage prediction. Subsequently, we enhance the proposed approach by incorporating a second deep RL algorithm—dueling DQN—which is an improvement of DQN, resulting in a 10% improvement in the results, especially in terms of voltage prediction. The proposed approach results in an accurate VFRB model that can be generalized to several types of redox-flow batteries. KW - energy storage KW - redox-flow battery KW - battery modeling KW - battery state variables KW - parameter optimization KW - accurate estimation KW - voltage prediction KW - deep reinforcement learning KW - deep q-learning KW - dueling deep q-networks Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-13994 VL - 10 PB - MDPI CY - Basel ER - TY - JOUR A1 - Rowedder, Simon A1 - Wilcox, Phill A1 - Brandtstädter, Susanne T1 - Negotiating Chinese Infrastructures of Modern Mobilities: Insights from Southeast Asia JF - Advances in Southeast Asian Studies (ASEAS) N2 - Since the launch of the BRI, particular modes of movement are integral to its vision of what it means to be a modern world citizen. Nowhere is this more apparent than in Southeast Asia, where China-backed infrastructure projects expand, and at great speed. Such infrastructure projects are carriers of particular versions of modernity, promising rapid mobility to populations better connected than ever before. Yet, until now, little attention has been paid to how mobility and promises of mobility intersect with local understandings of development. In the introduction to this special issue, we argue that it is essential to think about the role infrastructure plays in forms of development that place connectivity at the center. We suggest that considering development, mobility and mo-dernity together is enlightening because it interrogates the connections between these interlocking themes. Through an introduction to five ethnographically grounded papers and two commentaries, all of which engage with infrastructures in different contexts throughout Southeast Asia, we demonstrate that there are significant gaps between of-ficial policy and lived experience. This makes the need to interrogate what infrastructure, mobilities, and global China really mean all the more pressing. KW - Belt and Road Initiative (BRI) KW - China-Backed Infrastructure KW - Development KW - Mobility KW - Southeast Asia Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-13973 VL - vol. 16 IS - no. 2 SP - 175 EP - 188 ER - TY - JOUR A1 - Hassen, Wiem Fekih A1 - Imen Azzouz, Imen Azzouz T1 - Optimization of Electric Vehicles Charging Scheduling Based on Deep Reinforcement Learning: A Decentralized Approach JF - Energies N2 - The worldwide adoption of Electric Vehicles (EVs) has embraced promising advancements toward a sustainable transportation system. However, the effective charging scheduling of EVs is not a trivial task due to the increase in the load demand in the Charging Stations (CSs) and the fluctuation of electricity prices. Moreover, other issues that raise concern among EV drivers are the long waiting time and the inability to charge the battery to the desired State of Charge (SOC). In order to alleviate the range of anxiety of users, we perform a Deep Reinforcement Learning (DRL) approach that provides the optimal charging time slots for EV based on the Photovoltaic power prices, the current EV SOC, the charging connector type, and the history of load demand profiles collected in different locations. Our implemented approach maximizes the EV profit while giving a margin of liberty to the EV drivers to select the preferred CS and the best charging time (i.e., morning, afternoon, evening, or night). The results analysis proves the effectiveness of the DRL model in minimizing the charging costs of the EV up to 60%, providing a full charging experience to the EV with a lower waiting time of less than or equal to 30 min. KW - smart EV charging KW - day-ahead planning KW - deep Q-Network KW - data-driven approach KW - waiting time KW - cost minimization KW - real dataset Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-13985 VL - 16 PB - MDPI CY - Basel ER - TY - THES A1 - Daschner, Stefan T1 - Essays on Trust, Behavior, and Decision-Making in the Human-Algorithm Interaction N2 - With recent progresses in the field of artificial intelligence (AI), algorithms can support more complex tasks (Frey and Osborne, 2017) that seemed safe from automation a few years ago (Brynjolfsson and McAfee, 2012). They can even outperform human decision-making in many task domains (Meehl, 1954; Dawes et al., 1989). The prominent defeat of Garry Kasparov, the world champion in chess, in 1997 is a milestone for the potentials of algorithms, increasing the value of IBM’s stock increased by $18 billion (Norvig and Russell, 2010). More recently, universal chatbots such as ChatGPT and the Bing Chatbot Sydney can influence millions of users and provide them answers to a broad range of tasks. To gain a competitive edge, companies invest heavily in algorithmic systems (Kappelman et al., 2021), which are considered as one of the most important drivers of today’s economy (Brynjolfsson and McAfee, 2011; Hogharth and Makridakis, 1981; Önkal et al., 2019). Particularly in management accounting, an algorithmic data analysis offers the potential to support a high decision quality, making their usage a key factor for success. However, algorithms can not only support, but also manipulate human decision-making (Roose et al., 2023). Algorithmic advice can lead to overtrust, i.e. to the heuristic replacement of vigilant information seeking and processing in favor of the advice provided (Mosier et al., 2001). The implementation of algorithmic decision support systems is thus no panacea to improve human decision-making. In contrast, they can entail new risks, such as the uncritical use of these algorithms (Boden, 2016). Yet, this ‘dark side’ of algorithms is not sufficiently investigated in the field of management accounting. With advances in machine learning, algorithmic support can become even more of a black box, blurring the reference points for evaluating its advice quality and thus increasing the risk of overtrust. Stephen Hawking even warns that AI will be “either the best, or the worst thing, ever to happen to humanity” (Alex Hern in: The Guardian: Stephen Hawking: AI will be 'either best or worst thing' for humanity, 19th October 2016). Interacting with such algorithmic systems therefore requires data literacy skills for an appropriate use. They seem to be a crucial prerequisite in today’s data-driven world to reap of the benefits of algorithmic systems. If no reflective and critical interaction between human and algorithm can be ensured, the trend towards a digitalized world will be a race against the algorithm (Brynjolfsson and McAfee, 2011). This dissertation takes this understudied critical perspective on the increasing implementation of algorithmic systems and sheds light on different aspects of human-algorithm interaction, ranging from the ability to use data visualization tools to trust calibrations and critical evaluations of algorithmic advices. Study I investigates an adequate information representation of subjective multiple criteria decision problems, an important task in management accounting, to support human decision-making. Study II distinguishes different designs of the human-algorithm interaction investigated in the trust in automation literature and compiles factors influencing the calibration of trust and behavior toward the true capabilities of the algorithm. Study III examines the role of performance feedback on trust and advice usage in a forecasting task for a better understanding of the recently observed phenomenon ‘algorithm aversion’. Finally, Study IV focusses on the risk of overtrust in advice in repeated interactions with a forecasting advisor and investigates the calibration of advice usage. Each study thereby represents an independent contribution and contains all information relevant to the respective research questions asked in the study. KW - artifical intelligence KW - algorithmic advice Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-14749 ER - TY - THES A1 - Stoffer, Gloria T1 - Three essays on b2b solution selling - challenges in sales, contracting, and pricing N2 - Offering solutions impose manifold challenges on suppliers. To master these challenges, suppliers need excellent commercial capabilities. This thesis considers these challenges and opportunities in sales, contracting, and pricing of complex B2B solutions in three essays: Essay 1 addresses the increased complexity for solution salespeople, who represent an essential strategic asset in solution selling. In-depth interviews with solution sales managers in study 1 and survey data from matched sales manager-salesperson dyads in study 2, reveal nine specific equifinal configurations of key personal and procedural competencies that qualify individual salespeople in their role and thus determine their solution sales success. The focus of essay 2 lies on B2B export relationships for complex product-service combinations in an international context. A regression analysis based on a survey study with 198 responses shows several direct and indirect effects of contractual and cultural constructs. The results give insights under which cultural framework conditions contract specificity serves as a safeguarding mechanism against uncertainty and opportunism. Essay 3 examines how the bidirectional agency relationship between suppliers and customers and the performance uncertainty of a solution influence B2B customers’ acceptance of performance-based pricing (PBP). Drawing on a cross-industry survey with 196 managers of B2B firms, this study contributes to extend PBP literature by showing how bidirectional agency relationships shape customers’ acceptance of PBP. In sum, this thesis contributes to a better understanding on how to optimize commercial capabilities in the context of national and international solution selling. It thereby focuses on addressing recently identified causes that hinder B2B firms from increasing their margins through solution selling by (1) optimizing the sales force through a better understanding of important resources and capabilities for solution selling, (2) optimizing their contractual set-up through a better understanding of cultural factors and the interplay with contract specificity, and 3) optimizing price policy through a better understanding of framework conditions, which have an impact on customers’ acceptance of PBP. KW - solution selling KW - customization KW - business-to-business Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-14728 ER - TY - THES A1 - Mladenov, Mladen T1 - Running in the Hamster Wheel. The Foreign Policy of Serbia between National Identity and the International Society. N2 - The thesis addresses a current topic related to the foreign policy of Serbia whereby Serbian foreign policy is analysed with reference to its domestic factors - in particular national identity - and also with regards to Serbia’s foreign factors, such as the Europeanization process and the nature of the international system. The overarching focus of the thesis is laid on the following puzzle: in spite of not attaining self-declared foreign policy goals and changing dynamics at the systemic level, Serbia’s foreign policy appear to be stable over time. In each of the five publications comprising the thesis, a narrower aspect of this puzzle is addressed. KW - Serbia; foreign policy analysis; nationalism; europeanisation Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-14702 ER - TY - INPR A1 - Klöpf, Tobias A1 - Wehner, Stefanie T1 - Vulnerabilities and capacities : dealing with coastal flooding in Ghana´s Volta Region N2 - Coastal flooding events pose an existential threat to populations around the world, particularly in the Global South. As a result of climate change and other, direct forms of anthropogenic interference, the magnitude and frequency of such floodings is predicted to continuously increase in the near future. Therefore, it is important to understand the vulnerability of affected people to implement appropriate measures. This research presents a case study on coastal flooding and its impact on livelihoods in the Volta Region of Ghana. The paper utilizes a vulnerability framework that focuses on exposure, susceptibility, as well as the capacities to anticipate, cope with, and recover from the effects of natural hazards. Based on a qualitative approach, the study focusses on those households who were directly affected of a severe tidal flood in November 2021, leading to a total destruction of their property. The research was conducted in March, July and August 2022. It revealed that the studied group had low capacity to anticipate and had no contingency plans in case of relocation. Further, we discovered different strategies that people applied to deal with the situation eight months after the flood event. Most households applied (short term) coping strategies to reestablish their former marine-based livelihood systems. Adaption in terms of long-term adjustment of their livelihoods played only a minor role and could be found in form of out-migration in a limited number of households. T3 - Migration, translocality and development in times of climate change. Mitra|WA Working Paper Series - 2 KW - Fishing community KW - Climate change adaption KW - Crisis migration KW - Displacement KW - Relocation Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-14597 IS - 2 CY - Passau ER - TY - JOUR A1 - Patil, Amit A1 - Ghasemi, Abdorasoul A1 - de Meer, Hermann T1 - Analysis of protection blinding in active distribution grids JF - IET Renewable Power Generation N2 - Protection blinding is a challenging issue in renewables-penetrated distribution grids and refers to a situation where a circuit breaker may not trip due to fault current contribution from distributed generation. This research addresses how the distributed generation location and capacity impact the operation of the circuit breaker in terms of the response time of the circuit breakers. The relative electrical distances of the faults and distributed generation to the circuit breakers are considered. The impact of distributed generation capacity considering the fault location is characterized using a new index called the heterogeneity index. The electrical distance between distributed generations and circuit breakers and the electrical distance between fault and circuit breaker is considered by a second new index called the electrical distance ratio. Data analysis on simulation results shows that these indices capture the phenomena of protection blinding caused by distributed generation. Results show that a higher distributed generation penetration and faults that are electri cally further away from a circuit breaker show severe cases of protection blinding captured by the indices. Furthermore, it is demonstrated how these indices can identify the worst impacted locations in the distribution grid. A key result is that protection blinding does not necessarily occur solely due to the presence of distributed generation between a circuit breaker and a fault, but is dependent on factors such as distributed generation location in the distribution grid, fault level, fault level distribution across the generation units and fault location. KW - General & introductory electrical electronics engineering Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-14661 ER - TY - THES A1 - Püllen, Dominik T1 - Holistic Security Engineering for Software-Defined Vehicles N2 - With the increasing use of digital technologies in the automotive sector, the traditional automobile is undergoing a structural transformation, requiring new technologies and enabling innovative mobility concepts. In particular, the ability to drive automatically or even fully autonomously, update control software, and remain connected to the environment allows attackers to infiltrate highly critical vehicle systems and take control without adequate protection. Once not only individual vehicles but entire fleets are dominated by software, cyberattacks could disrupt a significant portion of the infrastructure and expose passengers to substantial risks. This work follows a holistic approach to protecting highly automated software-defined vehicles from cyberattacks by designing and implementing security concepts in the main phases of a vehicle's lifecycle. We use SAE level 4 prototype vehicles to evaluate our proposed techniques. We start with a systematic security requirement analysis using the ISA-62443 standard series, demonstrating how threats can be identified in a collaborative, hierarchical process and how the resulting security risks impact the software and hardware architecture of a self-driving vehicle. We show how this analysis process results in concrete requirements whose consideration reduces the overall security risk to a tolerable level. Subsequently, we develop technical solutions for selected requirements. We begin by securing the CAN and FlexRay legacy protocols, which we foresee being used in specific areas of SDV in a transitional period despite technological changes. To enable vehicle-wide security management, we address the management and distribution of cryptographic keys within such networks, mainly focusing on resource-constrained devices. We propose using lightweight implicit certificates for deriving cryptographic group keys that can be used in CAN networks. Additionally, we demonstrate how the slot-based frame structure of the FlexRay protocol allows for efficient "multi-slot" authentication, for which we calculate cryptographic keys using hash-based key chains. SDV use Ethernet-based communication protocols and custom middleware stacks to transmit large amounts of data in real-time. We develop a three-stage security process for the novel ASOA, which enables the development and central orchestration of system-agnostic functional software components on embedded systems and HPC platforms. After the central specification of the security architecture at the data flow level, security tokens are automatically calculated and distributed for runtime protection of the service-oriented, DDS-based data transmission. Our process ensures the strict separation of function and system knowledge, allowing for cost-effective and adaptable security architecture management. The evaluation in four self-driving, software-defined vehicles demonstrates an average runtime overhead of approximately 5.71%. As the initial risk analysis and actual cyberattacks have shown, protective measures against the compromise of control units must be taken alongside communication security. To address this, we develop a method for verifying and validating the software integrity of control units. A governmental third party confirms a measurement through a digital certificate, proving the examined vehicle's trustworthiness and suitability for participation in automated traffic. In the final step of this work, we present an assessment scheme that allows software-defined vehicles to evaluate security incidents during operation in terms of their maximum expected damage and initiate appropriate countermeasures. We follow the ISO/SAE 21434 standard and model attack paths using a graph representing dependencies among internal vehicle assets to account for the propagation effects of cyberattacks. The assessment of a security incident considers not only the probability of individual attack paths but also the vehicle context. Our practical evaluation demonstrates that we can detect, report, and assess security incidents below the human reaction time in the earlier mentioned prototype vehicles. Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-14497 ER - TY - THES A1 - Donner, Eva Katharina T1 - 4 Essays on Sustainable Development and Organizations’ Response to Stakeholder’s Expectations N2 - As integral part of the society, environment, and economy, the organization’s survival and growth depend on legitimacy which reflects the social support and acceptance of its stakeholders, the institutions and individuals it interacts with. Organizations interact with internal and external stakeholder groups which not necessarily have the same legitimacy expectations. Due to several reasons, such as the adoption of new laws or the invention of new technologies, stakeholders’ expectations of legitimate actions can change in the course of time. Thus, to respond to changing stakeholder’s expectations, as integral part of a changing environment, is complex. The main objective of this dissertation is to answer the research question: “How do organizations respond to changing stakeholder’s expectations in context of sustainable development?”. Building on two empirical settings with four essays, this dissertation provides insights into organizations’ responses as reaction to changing stakeholder expectations with regard to sustainable development. In particular, it takes a closer look on the interplay between internal stakeholders, such as employees, and external stakeholders, such as politics or customers. The first essay summarizes the organizational factors for the implementation of a research data management (RDM) system within higher education institutes (HEI) and how they interact with each other. Based on Leavitt’s (1965) classical model of organizational change, the essay provides an overview about the interrelation between the individual components that make up an RDM system. The second essay investigates how early career researchers within HEI make use of different respond strategies to the state, market, professional, and community logic in context of RDM. It provides insights how employees deal with changing environmental conditions and the organization’s response to them. The third essay analyses the shift from voluntary to mandatory sustainability reporting and demonstrates different strategies organizations adopt to respond to it. The fourth essay incorporates the findings of the third essay and investigates which factors influence the organization’s strategy to respond. It focuses on the interface between the top management team and the chief executive officer. This dissertation makes at least two overall contributions to management and organization studies research. First, it emphasizes the role of different stakeholder groups and their impact on the organizations’ activities. Second, this dissertation shows the value of connecting different theoretical approaches such as institutional logics, upper echelon theory, and organizational transparency research in context of organizational legitimacy and demonstrates that a nuanced view is necessary to understand the concept of organizational legitimacy. This cumulative dissertation is structured as follows. Part A is an introduction to the study organizational legitimacy. Part B contains the four essays. KW - Legitimacy KW - Strategisches Management Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-14516 ER - TY - THES A1 - Fritz, Manuela T1 - Health challenges of the 21st century - Empirical essays on the health and economic burden of non-communicable diseases and climate change in Southeast Asia N2 - In the ongoing 21st century, low- and middle-income countries will face two health challenges that are thoroughly different from what these countries have been dealing with in preceding centuries. First, they are confronted with surging rates of non-communicable diseases (NCDs), and second, climate change will take its toll and is predicted to cause catastrophic health impairments and exacerbate chronic health conditions further. Both will pose a disproportionate health and economic burden on low- and middle-income countries, which are also the countries least able to cope with them. By threatening individual health and socioeconomic improvements, and by putting an immense burden on already constrained health care systems, they impede the progress in poverty reduction and widen health inequities between the rich and the poor. Against this background, this thesis investigates the potential of NCD prevention and treatment measures in the context of Southeast Asia, with case studies in Indonesia. Specifically, it seeks to understand what kind of health interventions have the potential to be (cost-)effective considering the cultural background, lifestyle, health literacy and health system capacities in the region. Further, this thesis analyzes the interplay between NCDs and climate change and assesses the financial burden that both might pose in the decades to come. Hence, this thesis contributes to a better understanding of how the two health challenges of the 21st century, NCDs and climate change, can be addressed in the context of Southeast Asia and offers insights into what type of health policies and interventions can play a supportive role. KW - Health KW - Climate change KW - Non-communicable diseases KW - Southeast Asia Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-12649 ER - TY - THES A1 - Alhamzeh, Alaa T1 - Language Reasoning by means of Argument Mining and Argument Quality N2 - Understanding of financial data has always been a point of interest for market participants to make better informed decisions. Recently, different cutting edge technologies have been addressed in the Financial Technology (FinTech) domain, including numeracy understanding, opinion mining and financial ocument processing. In this thesis, we are interested in analyzing the arguments of financial experts with the goal of supporting investment decisions. Although various business studies confirm the crucial role of argumentation in financial communications, no work has addressed this problem as a computational argumentation task. In other words, the automatic analysis of arguments. In this regard, this thesis presents contributions in the three essential axes of theory, data, and evaluation to fill the gap between argument mining and financial text. First, we propose a method for determining the structure of the arguments stated by company representatives during the public announcement of their quarterly results and future estimations through earnings conference calls. The proposed scheme is derived from argumentation theory at the micro-structure level of discourse. We further conducted the corresponding annotation study and published the first financial dataset annotated with arguments: FinArg. Moreover, we investigate the question of evaluating the quality of arguments in this financial genre of text. To tackle this challenge, we suggest using two levels of quality metrics, considering both the Natural Language Processing (NLP) literature of argument quality assessment and the financial era peculiarities. Hence, we have also enriched the FinArg data with our quality dimensions to produce the FinArgQuality dataset. In terms of evaluation, we validate the principle of ensemble learning on the argument identification and argument unit classification tasks. We show that combining a traditional machine learning model along with a deep learning one, via an integration model (stacking), improves the overall performance, especially in small dataset settings. In addition, despite the fact that argument mining is mainly a domain dependent task, to this date, the number of studies that tackle the generalization of argument mining models is still relatively small. Therefore, using our stacking approach and in comparison to the transfer learning model of DistilBert, we address and analyze three real-world scenarios concerning the model robustness over completely unseen domains and unseen topics. Furthermore, with the aim of the automatic assessment of argument strength, we have investigated and compared different (refined) versions of Bert-based models that incorporate external knowledge in the decision layer. Consequently, our method outperforms the baseline model by 13 ± 2% in terms of F1-score through integrating Bert with encoded categorical features. Beyond our theoretical and methodological proposals, our model of argument quality assessment, annotated corpora, and evaluation approaches are publicly available, and can serve as strong baselines for future work in both FinNLP and computational argumentation domains. Hence, directly exploiting this thesis, we proposed to the community, a new task/challenge related to the analysis of financial arguments: FinArg-1, within the framework of the NTCIR-17 conference. We also used our proposals to react to the Touché challenge at the CLEF 2021 conference. Our contribution was selected among the «Best of Labs». KW - NLP, Argument Mining, Argument Quality Assessment, Financial Argumentation, Earnings Conference Calls Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-12699 ER - TY - JOUR A1 - Donner, Eva Katharina T1 - Research data management systems and the organization of universities and research institutes: A systematic literature review JF - Journal of Librarianship and Information Science N2 - New technological developments, the availability of big data, and the creation of research platforms open a variety of opportunities to generate, store, and analyze research data. To ensure the sustainable handling of research data, the European Commission as well as scientific commissions have recently highlighted the importance of implementing a research data management system (RDMS) in higher education institutes (HEI) which combines technical as well as organizational solutions. A deep understanding of the requirements of research data management (RDM), as well as an overview of the different stakeholders, is a key prerequisite for the implementation of an RDMS. Based on a scientific literature review, the aim of this study is to answer the following research questions: “What organizational factors need to be considered when implementing an RDMS? How do these organizational factors interact with each other and how do they constrain or facilitate the implementation of an RDMS?” The structure of the analysis is built on the four components of Leavitt’s classical model of organizational change: task, structure, technology, and people. The findings reveal that the implementation of RDMS is strongly impacted by the organizational structure, infrastructure, labor culture as well as strategic considerations. Overall, this literature review summarizes different approaches for the implementation of an RDMS. It also identifies areas for future research. KW - Data handling KW - information infrastructure KW - organization KW - organizational change KW - research data management KW - research data management system Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-12654 SN - 0961-0006 SN - 1741-6477 VL - 55 IS - 2 SP - 261 EP - 281 PB - SAGE Publications CY - Sage UK: London, England ER - TY - JOUR A1 - Sengl, Michael A1 - Heinke, Elfi T1 - Teaching Journalism Literacy in Schools: The Role of Media Companies as Media Educators in Germany JF - Media and Communication N2 - German journalism is facing major challenges including declining circulation, funding, trust, and political allegations of spreading disinformation. Increased media literacy in the population is one way to counter these issues and their implications. This especially applies to the sub‐concept of journalism literacy, focusing on the ability to consume news critically and reflectively, thus enabling democratic participation. For media companies, promoting journalism literacy seems logical for economic and altruistic reasons. However, research on German initiatives is scarce. This article presents an explorative qualitative survey of experts from seven media companies offering journalistic media education projects in German schools, focusing on the initiatives’ content, structure, and motivation. Results show that initiatives primarily aim at students and teachers, offering mostly education on journalism (e.g., teaching material) and via journalism (e.g., journalistic co‐production with students). While these projects mainly provide information on the respective medium and journalistic practices, dealing with disinformation is also a central goal. Most initiatives are motivated both extrinsically (e.g., reaching new audiences) and intrinsically (e.g., democratic responsibility). Despite sometimes insufficient resources and reluctant teachers, media companies see many opportunities in their initiatives: Gaining trust and creating resilience against disinformation are just two examples within the larger goal of enabling young people to be informed and opinionated members of a democratic society. KW - disinformation KW - journalism literacy KW - ournalistic media education KW - media literacy KW - news media literacy Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-12499 VL - volume 11 IS - issue 2 SP - 53 EP - 63 PB - Cogitatio Press CY - Lisbon, Portugal ER - TY - THES A1 - Graßl, Isabella T1 - Diversity in Programming Education: Effects of Topic and Group Constellation on Young Programming Novices N2 - The field of software engineering faces a significant diversity crisis, characterized by a critical lack of heterogeneity despite ongoing efforts to promote gender equality. The persistent male dominance in this domain has created an urgent need for more heterogeneous groups in software engineering. This lack of diversity not only hinders underrepresented groups from entering the field but also prevents them from gaining initial programming experiences, which are a core component of software engineering and essential for developing computational thinking. To address this crisis and its implications, early interventions are key in shaping positive perceptions, building confidence, and sparking initial interest in programming among underrepresented groups before societal stereotypes of programming as a nerdy field manifests. This means starting with basic programming courses for children and continuing through to first-year university students in order to foster technical skills and computational thinking, alongside creativity and collaboration. However, there is limited understanding of how introductory programming course designs impact diversity-dependent characteristics to create welcoming and learning-friendly environments. This understanding is particularly important for underrepresented groups, especially girls, to benefit from their first programming experiences as they are often hindered by the initial perception of programming as (1) abstract and unappealing, and (2) non-social to novices. Engaging, creative, and relatable topics in programming courses might demystify complex programming concepts, making them more accessible, less intimidating, and appealing. However, understanding programming is not just about the content---it is also about the context in which it is learned. Introducing programming as social activity is important, particularly for young learners. By emphasizing team work, we might encourage collaboration and peer support, counteracting the lone-wolf programmer stereotype. Therefore, this doctoral thesis investigates the effects of both key aspects in programming courses---(1) topic choices and (2) group constellations---on young programming novices. The aim is to provide a holistic understanding of how different course designs can support diverse learners and promote gender equality in programming education. While this research primarily addresses gender diversity due to the persistent gender gap in software engineering, it also examines additional diversity dimensions, including age, ethnicity, prior programming experience, disabilities, and educational background. A total of 13 studies were conducted within this thesis, examining the current state of educational settings and utilizing various introductory programming courses designed for children aged 8 to 18, as well as first-year university students. These studies employed different programming environments, such as Scratch and Sonic Pi, and incorporated a variety of topics and group constellations to observe their effects on student outcomes. By using a mixed-methods design, data were gathered through surveys, observations, and both data-driven and manual code analysis. Key findings reveal that it is particularly noteworthy how children utilize the programming environment to engage with and creatively express topics aligned with their interests which also align mostly with gender-stereotypes, including elements from internet and popular culture as well as socio-cultural narratives. However, gender-sensitive and neutral topic choices enhance engagement, self-efficacy, contribution, code quality and creative output, while also contributing to reduce stereotypical beliefs about programming, particularly among girls. In line with the findings for the course topic, group constellations also influence programming experiences. In particular, introducing pair programming in courses shows a promising approach for young learners, but attention must be paid to mitigate socially learned gender-stereotypical behaviours. Another finding indicates that, unlike professional software teams, mixed-diverse student teams often encounter substantial challenges, thus benefit from clear communication guidelines and supportive environments to promote better collaboration. This doctoral thesis concludes with guidelines for designing more effective and inclusive introductory programming courses. These recommendations include using gender-sensitive course materials, allowing for creative freedom through topic choices while encouraging the use of advanced programming concepts, promoting collaboration through pair programming while fostering enhanced communication, boosting self-efficacy with quick positive feedback for girls in particular, and providing emotional support for underrepresented groups. By following these guidelines, educators can create more engaging, inclusive, and effective programming courses. This may ultimately promote a more equitable and diverse future generation of professional software developers while also fostering computational thinking, encouraging a broader interest in programming among all young learners. KW - Softwareentwicklung KW - Lernsituation Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-15049 ER - TY - THES A1 - Berger, Christian T1 - Towards Fast and Adaptive Byzantine State Machine Replication for Planetary-Scale Systems N2 - State machine replication (SMR) is a classical approach for building resilient distributed systems. In Byzantine fault-tolerant (BFT) systems, no concrete assumptions are made about the behavior of faulty replicas. With the advancement of distributed ledger technologies (DLT), planetary-scale BFT SMR ist becoming practical and necessary as it can serve as a consensus primitive to keep the ledger consistent. In our view, the alignment of BFT SMR to DLT brings new challenges, for instance the scalability aspect, where recent research works less frequently address latency improvements than throughput improvements. Further challenges include the geographic dispersion of replicas within a planetary-scale system and the need of a BFT SMR protocol to react to environmental changes during runtime. This thesis has the objective to improve BFT SMR for planetary-scale systems by lowering the protocol latency observed by clients and by making the BFT SMR system adaptive, i.e., enabling replicas to react to perceived changes such as changing network characteristics or faulty replicas. As a first contribution of this thesis, we discover that fast, consensus-free (read-only) operations is a flawed optimization in seminal BFT SMR frameworks, such as PBFT and BFT-SMaRt. We explain how the read-only optimization can violate the protocol's liveness by showing an attack and then present a solution that makes the overall, optimized protocol both live and linearizable. The second contribution is Adaptive Wide-Area Replication (AWARE), which enables a geo-replicated system to adapt to its environment, thus improving the geographical scalability of consensus if replicas are dispersed across the world. Essentially, AWARE is an automated and dynamic voting-weight tuning and leader positioning scheme, which supports the emergence of fast consensus quorums in the system and builds upon previous work, the WHEAT protocol. AWARE combines reliable self-monitoring with a consensus latency prediction model, thus striving to minimize the system’s consensus latency at runtime, which subsequently results in latency improvements observed by clients scattered across the globe, which we validate through experiments. The third contribution presents FlashConsensus, a protocol derived from AWARE, that also adjusts the resilience threshold. The core idea is the tentative use of a lower resilience threshold which leads to smaller consensus quorums and thus consensus acceleration in common-case scenarios where we expect only few faulty replicas. FlashConsensus achieves threat-level awareness through the incorporation of two modes of operation and BFT forensic support and guarantees liveness and linearizability under optimal resilience. Moreover, FlashConsensus allows for client-side speculation by using incremental consistency guarantees to further lower request latency. Additionally, we investigate on the question whether we can reason about the performance of large-scale systems utilizing simulations. We discover, that we can faithfully forecast the performance of BFT protocols by plugging real protocol implementations into a high-performance network simulator. For instance, simulation results reveal that, using 51 replicas scattered across the planet, FlashConsensus can finalize operations in less than 0.4 s, which is half of the time required for a PBFT-like protocol in the same network, and matching the latency of this protocol running on the best possible internet links (transmitting at 67% of the speed of light). N2 - Die Zustandsmaschinenreplikation (ZMR) ist ein klassischer Ansatz für zuverlässige verteilte Systeme. In Byzantinischen fehlertoleranten (BFT) Systemen werden keine konkreten Annahmen über das Verhalten von fehlerhaften Replikaten gemacht. Mit dem Voranschreiten der sog. „Distributed Ledger Technologien“ (DLT) wird planetare BFT ZMR praktikabel und notwendig, da sie als Konsensusprimitiv dienen kann, um die Konsistenz einer Blockchain aufrechtzuerhalten. Unserer Ansicht nach bringt die Ausrichtung von BFT ZMR an DLT neue Herausforderungen mit sich, z.B. den Skalierbarkeitsaspekt, bei dem jüngste Forschungsarbeiten seltener Latenzverbesserungen als Durchsatzverbesserungen untersuchen. Weitere Herausforderungen umfassen die geografische Verteilung von Replikaten innerhalb eines planetaren Systems sowie die Notwendigkeit eines BFT ZMR Protokolls während der Laufzeit auf Veränderungen zu reagieren. Diese Dissertation verfolgt das Ziel, die BFT ZMR für planetare Systeme durch Senkung der von Clients beobachteten Protokolllatenz zu verbessern und die BFT ZMR-Systeme anpassungsfähig zu machen, indem Replikate auf wahrgenommene Änderungen wie sich ändernde Netzwerkcharakteristiken oder fehlerhafte Replikate reagieren können. Als erster Beitrag dieser Dissertation zeigen wir, dass schnelle, konsensusfreie (nur-lesende) Operationen in grundlegenden BFT ZMR Protokollen, wie PBFT und BFT-SMaRt, eine fehlerhafte Optimierung sind. Wir erklären, wie die nur-lesende Optimierung die Liveness (Verfügbarkeit von Operationen) des Protokolls verletzen kann, indem wir einen Angriff präsentieren und dann eine Lösung vorschlagen, die das insgesamt optimierte Protokoll sowohl live (verfügbar) als auch linearisierbar („linearizable“ -- streng konsistent) macht. Der zweite Beitrag ist Adaptive Wide-Area Replication (AWARE), mit der ein geo-repliziertes System sich an seine Umgebung anpassen kann und damit die geografische Skalierbarkeit des Konsensus verbessert, wenn Replikate auf der ganzen Welt verteilt sind. Im Wesentlichen ist AWARE ein automatisches und dynamisches Stimmgewichtseinstellungs- und Anführerpositionierungs-schema, das die Entstehung schneller Konsensusquoren im System unterstützt und auf früheren Arbeiten, wie dem WHEAT-Protokoll, aufbaut. AWARE kombiniert zuverlässige Selbstüberwachung mit einem Konsensuslatenzvorhersagemodell und strebt danach, die Konsensuslatenz des Systems zur Laufzeit zu minimieren, was letztendlich zu Latenzgewinnen führt, die von Clients auf der ganzen Welt beobachtbar sind, was wir durch Experimente bestätigen. Der dritte Beitrag stellt FlashConsensus vor, ein Protokoll, das aus AWARE abgeleitet ist und auch die Resilienzschwelle anpasst. Die Kernidee ist die vorübergehende Verwendung einer niedrigeren Resilienzschwelle, die zu kleineren Konsensusquoren und damit zu einer Beschleunigung des Konsensus in häufigen Fällen führt, in denen nur wenige fehlerhafte Replikate erwartet werden. FlashConsensus erkennt und reagiert auf Bedrohungen durch die Einbeziehung von zwei Betriebsarten und BFT-Forensikunterstützung und garantiert Liveness sowie Konsistenz unter optimaler Resilienz. Darüber hinaus ermöglicht es die Spekulation auf Clientseite durch die Verwendung inkrementeller Konsistenzgarantien, um die Clientlatenz weiter zu senken. Zusätzlich werden wir uns mit der Frage beschäftigen, ob wir die Performanz von groß-skalierten Systemen mittels Simulationen beurteilen können. Wir stellen fest, dass wir die Performanz von BFT Protokollen durch das Einstöpseln von echten Protokollimplementierungen in einen hochleistungsfähigen Netzwerksimulator zuverlässig vorhersagen können. Beispielsweise zeigen Simulationen, dass FlashConsensus mit 51 Replikaten, die auf der ganzen Welt verteilt sind, Operationen in weniger als 0,4 s linearisierbar verarbeiten kann, was die Hälfte der Zeit ist, die für ein PBFT-ähnliches Protokoll im gleichen Netzwerk erforderlich ist und ähnlich schnell ist wie dieses Protokoll mit bestmöglichen Internetverbindungen (Übertragung mit 67% der Lichtgeschwindigkeit). KW - Byzantine fault tolerance KW - state machine replication KW - consensus KW - adaptiveness KW - planetary-scale Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-15059 ER - TY - THES A1 - Sentanoe, Stewart T1 - VMIaaS: Virtual Machine Introspection as a Service N2 - In this digital era, communication in the digital world is becoming part of our daily lives. One key technology that becomes part of this digital transformation is cloud computing. It allows users to have a running system as a virtual machine (VM) on the cloud without owning a physical server. Unfortunately, adversaries can also use those systems to conduct criminal activities. Therefore, developing a method to extract evidence from those systems is also necessary. One way is through digital forensics, and one method to do digital forensics of a VM is using virtual machine introspection (VMI). However, VMI has yet to be made available by any public cloud provider. This thesis addresses this issue by introducing methods for deploying VMI on public cloud providers. Four main challenges have to be solved. Firstly, VMI requires access to the hypervisor, which practically can access all VMs running on the same server. This leads to security and privacy issues where customers can introspect each other VMs. To solve this problem, this thesis introduces KVMIveggur, a versatile access control of VMI. It comes with different options that every customer can choose from based on their needs. Secondly, VMI introduces overhead to the running VM. This is because most of the introspection mechanisms perform data access to the monitored VM. Performing data access on a running VM can cause data inconsistency. Hence, pausing the VM before executing the data access is better. However, when the VM pausing frequency is high, it will affect the performance of the monitored VM. The current state-of-the-art techniques use caching to reduce the VM pausing frequency. However, it faces a problem: the cached data may be outdated compared to the actual data. Therefore, this thesis introduces VMIFresh, a better caching mechanism. We leverage both active and passive tracing mechanisms to ensure high performance and consistency of the data (freshness). Thirdly, many state-of-the-art VMI libraries and applications run perfectly only on Intel processors because Intel CPUs provide the best hardware support for VMI. However, AMD and ARM processors are getting more popular in cloud computing. Thus, it is necessary to retrofit VMI capabilities to support AMD and ARM processors. This thesis describes the requirements to employ VMI on AMD and ARM processors. We also provide the implementation of those requirements. Finally, to do introspection using VMI, it is crucial to have proper symbol information (layout and location of data structures) of the introspected operating system (OS) and user applications. While many existing VMI approaches concentrate primarily on analyzing OS data structures, analyzing user application data often receives no attention. In our approach, we address this gap by focussing on application-level introspection. We have identified several use cases that require this kind of introspection. We focus on cryptographic key extraction for two specific instances: secure shell (SSH) and transport layer security (TLS) by leveraging the power of machine learning techniques to locate those keys in the main memory effectively and efficiently. After we had solved those challenges, we combined a couple of our approaches and introduced two VMI applications: Sarracenia and VMIGuard. Sarracenia is a deception technology that tracks activities done on an SSH session. The main goal of Sarracenia is to attract adversaries away from the production system and learn about their behavior. On the other hand, VMIGuard also monitors the SSH traffic. But, it specifically monitors the activity of any git-related activities. The main goal of VMIGuard is to ensure the integrity of the hosted data from any internal malicious actor. KW - Cloud Computing KW - Computersicherheit Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-15027 ER - TY - THES A1 - Ghaffar, Abdul Muqeet T1 - Understanding Individuals’ Willingness for Prosocial Data Disclosure: Exploring Antecedents and Investigating Strategies for its Promotion N2 - Privacy research has traditionally focused on understanding individuals' behavior in disclosing personal data by assuming that individuals disclose their data mainly out of self-interest. However, in many contexts, individuals disclose their data primarily for the benefit of others and society, thereby showing a form of prosocial behavior. This dissertation conceptualizes these types of data disclosure as prosocial data disclosures and argues that existing privacy research frameworks, such as the privacy calculus, have not been sufficiently applied in privacy research and need to be reevaluated to fully capture the complexities of prosocial data disclosures. Despite the growing relevance of understanding individuals’ willingness for prosocial data disclosures, existing research in this field is limited. This dissertation consists of four essays that seek to deepen the understanding of the underlying decision-making processes of individuals by exploring the antecedents and investigating strategies that promote prosocial data disclosure. By employing different research methods, including systematic literature reviews, qualitative and quantitative surveys, interviews, workshops, and conjoint analysis, this dissertation contributes to the identification of the multifaceted antecedents of prosocial data disclosure which can be classified into different drivers and barriers. Furthermore, by integrating insights from different disciplines such as behavioral economics, social psychology, and information systems research, this dissertation provides empirical evidence for the use of message framing and the deliberate emphasis on impact uncertainty as two promising strategies in promoting prosocial data disclosure. The findings derived from all four essays inform privacy research and prosocial behavior research about the need for sophisticated theories that are capable of better capturing the complexities of prosocial data disclosure. Additionally, the findings offer practical implications for designing ethically responsible data disclosure practices while respecting individual privacy rights. KW - privacy KW - behavioral economics KW - social psychology KW - message framing KW - impact uncertainty Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-15001 ER - TY - THES A1 - Masselus, Lise T1 - Evaluating Poverty Alleviation: Essays on Microfinance, Energy Access and Limits to the Gold Standard in Empirical Economics N2 - In my dissertation, I combine topical contributions on microfinance and energy access, two prevalent poverty alleviation policies, with methodological contributions on how empirical economics research can contribute to effective policymaking. Chapter 1 reviews the existing experimental evidence on microfinance. We use this deep literature to highlight challenges in generalizing from empirical research. Chapter 2 and 3 provide empirical insights on the energy access-poverty nexus. We study the long-term adoption of grid electrification and evaluate whether productive use can foster adoption and impact. Chapter 4 addresses data quality, an essential yet often overlooked element in research and policymaking. This introduction provides a general overview on microfinance, energy access, and methodological critiques on common practices in empirical economics research. [from the introduction] KW - energy access KW - microfinance KW - meta-science KW - survey methods Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-14981 ER - TY - JOUR A1 - Deiner, Adina A1 - Feldmeier, Patric A1 - Fraser, Gordon A1 - Schweikl, Sebastian A1 - Wang, Wengran T1 - Automated test generation for SCRATCH programs JF - Empirical Software Engineering N2 - The importance of programming education has led to dedicated educational program- ming environments, where users visually arrange block-based programming constructs that typically control graphical, interactive game-like programs. The SCRATCH programming environment is particularly popular, with more than 90 million registered users at the time of this writing. While the block-based nature of S CRATCH helps learners by preventing syntactical mistakes, there nevertheless remains a need to provide feedback and support in order to implement desired functionality. To support individual learning and classroom settings, this feedback and support should ideally be provided in an automated fashion, which requires tests to enable dynamic program analysis. In prior work we introduced W HISKER , a framework that enables automated testing of S CRATCH programs. However, creating these automated tests for S CRATCH programs is challenging. In this paper, we therefore investigate how to automatically generate W HISKER tests. Generating tests for S CRATCH raises important challenges: First, game-like programs are typically randomised, leading to flaky tests. Second, S CRATCH programs usually consist of animations and interactions with long delays, inhibiting the application of classical test generation approaches. Thus, the new application domain raises the question of which test generation technique is best suited to produce high coverage tests capable of detecting faulty behaviour. We investigate these questions using an extension of the W HISKER test framework for automated test generation. Evaluation on common programming exercises, a random sample of 1000 S CRATCH user programs, and the 1000 most popular S CRATCH programs demonstrates that our approach enables W HISKER to reliably accelerate test executions, and even though many SCRATCH programs are small and easy to cover, there are many unique challenges for which advanced search-based test generation using many-objective algorithms is needed in order to achieve high coverage. KW - Search-based testing KW - Block-based programming KW - SCRATCH Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:101:1-2023091108301581209964 VL - 28 IS - 3 SP - 1 EP - 63 PB - Springer Nature CY - Berlin ER - TY - JOUR A1 - Narh, John T1 - The resource curse and the role of institutions revisited JF - Environment, Development and Sustainability N2 - Many studies have shown that natural resource abundant countries with strong institutions tend to escape the resource curse. Institutional quality has been examined using broad indices of rule of law, the rate of murder, the share of the shadow economy and provision of public goods. Nonetheless, we need to locate the specific institutional conditions under which the curse manifests since some “rule of law” countries like Nigeria and Angola are generally classified as resource cursed. In this review, I argue that managing and distributing natural resource wealth through a centralised planning strategy and lack of a binding long-term national development plan are institutional conditions that encourage government unaccountability as they do not restrict policy makers against discretionary distribution of natural resource windfall, rent seeking, clientelism and corruption which contribute to poor economic development and growth. Also, inadequate regulations on how to address the potential or actual impacts of natural resource extraction on the livelihood of local people and the environment tend to precipitate grievance-induced resource conflict. KW - Resource curse KW - Government accountability KW - Institutions KW - Natural resource KW - conflict KW - Natural resource windfall KW - Financial development Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:101:1-2024030609203689018522 VL - 27 SP - 8187 EP - 8207 PB - Springer Nature CY - Berlin ER - TY - JOUR A1 - Ertel, Florence A1 - Donig, Simon A1 - Eckl, Markus A1 - Gassner, Sebastian A1 - Göler, Daniel A1 - Rehbein, Malte T1 - Using web archives for an explorative study of the web presence of German parties during the European election 2019 JF - Quality & Quantity N2 - In the digital age, political science is faced with a shift of election campaigns and politi- cal discourse to digital or virtual arenas. Because the internet is a highly volatile medium and online content can become inaccessible after the campaign season, new challenges for research arise as well as the need for the preservation of online content. Moreover, the sheer volume of data researchers have to deal with has reached levels where traditional methods are being highly challenged. This paper puts forth a web harvesting workflow with a strong focus on granular extraction of unstructured information (publication dates) for automated analysis. As our approach is methodological, we would like to point out the benefits that researches in political science may draw from adapting our methodology. We demonstrate this by analysing an event-based web crawl of German parties participating in the election campaign for the European Parliamentary Election in 2019. We employ distant reading methods to generate topic models, which are subsequently evaluated by hermeneutic analysis of a subset of the data. KW - Web archives KW - European parliamentary election KW - Second order elections KW - Distant reading KW - Topic modelling Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:101:1-2023082609050515725791 VL - 58 IS - 1 SP - 603 EP - 625 PB - Springer Nature CY - Berlin ER - TY - JOUR A1 - Piwoni, Eunike A1 - Mußotter, Marlene T1 - The evolution of the civic–ethnic distinction as a partial success story: Lessons for the nationalism–patriotism distinction JF - Nations and Nationalism N2 - This article brings, for the first time, two of the most pivotal distinctions in nationalism studies into extended dialogue: the civic–ethnic distinction (CED) and the nationalism–patriotism distinction (NPD). By reviewing both the evolution of those distinctions over the previous decades and the ways in which they have been used in quantitative empirical research, we argue that the CED's evolution has been a partial success story, whereas discourse around the NPD has not seen substantial development. Despite lingering inconsistencies, researchers drawing on the CED have been successful in addressing different lines of critique and in using the CED as a heuristic for investigating notions of nationhood as expressed in public perceptions. In contrast, there has been only limited dialogue between theoretical and empirical approaches to the NPD. The article illustrates how research drawing on the NPD could profit from the CED's evolution. We close by providing a conceptual roadmap to guide the path towards more terminological clarity and to construct more theoretically robust measures for nationalism and patriotism. We specifically suggest that nationalism and patriotism should be consistently understood as ideal types that citizens can simultaneously hold to varying degrees. KW - civic nationalism KW - civic–ethnic distinction KW - ethnic–civic KW - national attachments KW - nationalism–patriotism distinction KW - nationhood KW - national identity KW - political psychology KW - surveys Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-16266 VL - 29 IS - 3 SP - 906 EP - 921 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Schwartz, Niels T1 - Topology of closure systems in algebraic lattices JF - Algebra universalis N2 - Algebraic lattices are spectral spaces for the coarse lower topology. Closure systems in algebraic lattices are studied as subspaces. Connections between order theoretic properties of a closure system and topological properties of the subspace are explored. A closure system is algebraic if and only if it is a patch closed subset of the ambient algebraic lattice. Every subset X in an algebraic lattice P generates a closure system〈X〉P . The closure system〈Y 〉P generated by the patch closure Y of X is the patch closure of〈X〉P. If X is contained in the set of nontrivial prime elements of P then〈X〉P is a frame and is a coherent algebraic frame if X is patch closed in P. Conversely, if the algebraic lattice P is coherent then its set of nontrivial prime elements is patch closed. KW - Poset KW - Complete lattice KW - Algebraic lattice KW - Frame KW - Closure system KW - Closure operator KW - Spectral space KW - Specialization KW - Coarse lower topology KW - Scott topology KW - Patch topology Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:101:1-2023090808111682406614 VL - 84 IS - 2 SP - 1 EP - 33 PB - Springer Nature CY - Berlin ER - TY - JOUR A1 - Münch, Miriam A1 - Rutter, Ignaz A1 - Stumpf, Peter T1 - Partial and Simultaneous Transitive Orientations via Modular Decompositions JF - Algorithmica N2 - A natural generalization of the recognition problem for a geometric graph class is the problem of extending a representation of a subgraph to a representation of the whole graph. A related problem is to find representations for multiple input graphs that coin- cide on subgraphs shared by the input graphs. A common restriction is the sunflower case where the shared graph is the same for each pair of input graphs. These problems translate to the setting of comparability graphs where the representations correspond to transitive orientations of their edges. We use modular decompositions to improve the runtime for the orientation extension problem and the sunflower orientation problem to linear time. We apply these results to improve the runtime for the partial represen- tation problem and the sunflower case of the simultaneous representation problem for permutation graphs to linear time. We also give the first efficient algorithms for these problems on circular permutation graphs. KW - Representation extension KW - Simultaneous representation KW - Comparability KW - graph KW - Permutation graph KW - Circular permutation graph KW - Modular decomposition Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:101:1-2024022914111908687000 VL - 86 IS - 4 SP - 1263 EP - 1292 PB - Springer Nature CY - Berlin ER - TY - JOUR A1 - Trautsch, Alexander A1 - Herbold, Steffen A1 - Grabowski, Jens T1 - Are automated static analysis tools worth it? An investigation into relative warning density and external software quality on the example of Apache open source projects JF - Empirical Software Engineering N2 - Automated Static Analysis Tools (ASATs) are part of software development best practices. ASATs are able to warn developers about potential problems in the code. On the one hand, ASATs are based on best practices so there should be a noticeable effect on software quality. On the other hand, ASATs suffer from false positive warnings, which developers have to inspect and then ignore or mark as invalid. In this article, we ask whether ASATs have a measurable impact on external software quality, using the example of PMD for Java. We investigate the relationship between ASAT warnings emitted by PMD on defects per change and per file. Our case study includes data for the history of each file as well as the differences between changed files and the project in which they are contained. We investigate whether files that induce a defect have more static analysis warnings than the rest of the project. Moreover, we investigate the impact of two different sets of ASAT rules. We find that, bug inducing files contain less static analysis warnings than other files of the project at that point in time. However, this can be explained by the overall decreasing warning density. When compared with all other changes, we find a statistically significant difference in one metric for all rules and two metrics for a subset of rules. However, the effect size is negligible in all cases, showing that the actual difference in warning density between bug inducing changes and other changes is small at best. KW - Static code analysis KW - Quality evolution KW - Software metrics KW - Software quality Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:101:1-2023091108203018898026 VL - 28 IS - 3 SP - 1 EP - 21 PB - Springer Nature CY - Berlin ER - TY - JOUR A1 - Frühwirth, Lorenz A1 - Prochno, Joscha T1 - Hölder’s inequality and its reverse — a probabilistic point of view JF - Mathematische Nachrichten N2 - In this article, we take a probabilistic look at Hölder's inequality, considering the ratio of terms in the classical Hölder inequality for random vectors in ℝ𝑛. We prove a central limit theorem for this ratio, which then allows us to reverse the inequality up to a multiplicative constant with high probability. The models of randomness include the uniform distribution on 𝓁𝑛𝑝 balls and spheres. We also provide a Berry–Esseen–type result and prove a large and a moderate deviation principle for the suitably normalized Hölder ratio. KW - Berry–Esseen bound KW - central limit theorem KW - Hölder’s inequality KW - 𝓁 𝑛 𝑝 ball KW - large deviation principle KW - moderate deviation principle KW - reverse inequality Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:101:1-2023062315175042989607 VL - 296 IS - 12 SP - 5493 EP - 5512 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Sommer, Tim T1 - Romantic objects, Victorian collections : scribal relics and the authorial body JF - Literature Compass N2 - Over the course of the nineteenth century, literary manuscripts came to be seen as tangible evidence of the creative process and as a key to the personality of the author. The material traces of writing were understood to outlive their creators and promise to resurrect the authorial body through the magic of the relic. This article reconstructs how authorial script gradually transformed into a collectible object pursued as a memento and a commodity. Letters, drafts, and fair copies by major modern writers found their way into the collections of British aristocrats and American industrialists at the same time that hunting for literary autographs diversified into a middle-class pursuit. Surveying recent scholarship on nineteenth-century collecting and material culture, the essay offers a condensed cultural history of the literary manuscript as a collectible and draws attention to how collectors and collecting feature in fictional texts of the period. It focuses on the artefactual mobility and custodial afterlives of Romantic papers in Victorian literature and culture, exploring a form of collecting which crossed boundaries between periods and national literary traditions. KW - archive KW - authorship KW - collecting KW - literary manuscripts KW - relics KW - Romanticism KW - Victorianism Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-16248 VL - 21 IS - 1-3 PB - Wiley CY - Hoboken ER - TY - THES A1 - Rose, Julian T1 - Poor Economics and the Long Term: Empirical Essays on Energy and Economic Poverty N2 - This dissertation explores different aspects of poverty specific to urban and rural areas. The first two chapters examine energy access for poor urban households, emphasizing the need for effective energy policies that ensure access while considering environmental and climate impacts. The final two chapters analyze the long-term effects of transfer programs targeting poor rural households, aiming to overcome poverty traps. The dissertation expands the methodological toolkit typically used in economics, addressing increasing concerns about the generalizability of experimental results, the narrow focus of research question in causal research, and the credibility crisis of empirical research. KW - Armut KW - Energieversorgung KW - Stadt KW - Ländlicher Raum KW - Wirtschaftshilfe Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-15124 ER - TY - THES A1 - Hofstadler, Julian T1 - Qualitative and quantitative convergence results for randomised integration methods N2 - In this thesis different randomised integration methods based on either, randomised Quasi-Monte Carlo, or (adaptive) Markov chain Monte Carlo methods are studied. Depending on the underlying integration problem we show qualitative and quantitative results, which ensure the asymptotic correctness of an algorithm or provide explicit error bounds. The first problem we consider is Lebesgue integration in the unit cube. We prove that a class of structured randomised integration methods is consistent w.r.t. convergence in mean and probability for any integrable function. Under slightly stronger integrability conditions we show that one also has almost sure convergence for median modified methods. We demonstrate the applicability of our theoretical results by considering randomly shifted lattice rules, randomised (t,d)-sequences, Latin hypercube samples, and randomised Frolov points. Secondly, we study integration w.r.t. probability measures which are available only via their non-normalised density. In this context we investigate Markov chain Monte Carlo methods which satisfy a spectral gap condition and functions which do not need to have a finite second moment. We prove error bounds for the absolute mean error where the rate of convergence is optimal. Illustrative scenarios where our theory is applicable are the random walk Metropolis algorithm as well as slice samplers. Finally, we study so-called adaptive increasingly rare Markov chain Monte Carlo algorithms. Based on a simultaneous Wasserstein contraction assumption we estimate the mean squared error and also prove bounds which characterise the path-wise convergence of the estimator. To demonstrate the applicability of our results we consider a number of examples, among which are doubly intractable distributions. Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-15196 ER - TY - THES A1 - Greifenstein, Luisa T1 - Supporting Primary School Programming Education through Formative Feedback N2 - Children are increasingly surrounded by computer science aspects in their everyday life. Primary school education aims at empowering children to participate in and reflect on their environment. Therefore, computer science related contents such as programming are increasingly introduced into primary school curricula. However, this also involves challenges in particular for teachers, who need to familiarise themselves with the new curriculum. As a result, primary school teachers often struggle to help primary school children with their programming issues. Corrective feedback given during the learning process (i. e. formative feedback) can help by promoting cognitive factors such as content knowledge. This thesis therefore aims to support primary school programming education through formative feedback. In order to shed light on different perspectives, both teachers and children participated in the studies in a mixed methods design. Teachers’ challenges and children’s programming issues were explored as a basis for knowing what both target groups struggle with. This was done by conducting content analysis on the challenges and issues collected and using the resulting categories for further quantitative analysis. The effects of different characteristics of feedback on the effectiveness and efficiency of teaching and learning programming were then explained. This was done by asking the teachers and children to explain their ratings and conducting content analysis on their explanations. The support of primary school programming education through formative feedback builds on the major challenge of teachers’ lack of content knowledge and the corresponding strategies of teacher training and automated feedback. Indeed, automated feedback was found to be mostly helpful for debugging and task creation. In order to provide direct support to children, common programming issues were identified in terms of the understanding of programming concepts and the usage of the programming environment. Effects on children’s learning and their preferences were identified for several feedback characteristics, leading for example to elaborated hints instead of simple direct instructions. Based on these results, a formative feedback approach of hint cards was developed and evaluated. The hint cards approach proved to be a useful example strategy for supporting primary school programming education through formative feedback. N2 - Kinder sind in ihrem Alltag zunehmend von informatischen Phänomenen umgeben. Die Grundschulbildung zielt darauf ab, Kinder zu befähigen, an ihrer Umwelt teilzuhaben und sie zu reflektieren. Daher werden informatikbezogene Inhalte wie das Programmieren zunehmend in die Lehrpläne der Grundschulen aufgenommen. Dies bringt jedoch auch Herausforderungen mit sich, insbesondere für die Lehrkräfte, die sich mit dem neuen Lehrplan und Ansätzen vertraut machen müssen. Infolgedessen fällt es Grundschullehrkräften oft schwer, Grundschulkindern bei ihren Programmierproblemen zu helfen. Korrektives Feedback, das während des Lernprozesses gegeben wird (formatives Feedback), kann helfen, indem es kognitive Faktoren wie fachliches Wissen fördert. Ziel dieser Arbeit ist es daher, den Programmierunterricht in der Grundschule durch formatives Feedback zu unterstützen. Um die unterschiedlichen Perspektiven zu beleuchten, nahmen sowohl Lehrkräfte als auch Kinder an den Studien in einem Mixed Methods-Design teil. Die Herausforderungen der Lehrkräfte und die Schwierigkeiten der Kinder bei der Programmierung wurden exploriert, um zu erfahren, womit beide Zielgruppen Probleme haben. Dazu wurden die gesammelten Herausforderungen und Probleme einer qualitativen Inhaltsanalyse unterzogen und die daraus resultierenden Kategorien für eine weitere quantitative Analyse verwendet. Außerdem wurden die Auswirkungen verschiedener Merkmale des Feedbacks auf die Effektivität und Effizienz des Lehrens und Lernens von Programmierkonzepten erklärt. Dazu erläuterten die Lehrkräfte und Kinder ihre Bewertungen und ihre Erläuterungen wurden einer qualitativen Inhaltsanalyse unterzogen. Die Unterstützung des Programmierunterrichts in der Grundschule durch formatives Feedback baut auf der großen Herausforderung des fehlenden fachlichen Wissens der Lehrkräfte und den entsprechenden Strategien der Lehrkräftebildung und des automatischen Feedbacks auf. Das automatische Feedback erwies sich beim Debugging und bei der Erstellung von Aufgaben als hilfreich. Um die Kinder direkt zu unterstützen, wurden allgemeine Programmierprobleme in Bezug auf das Verständnis von Programmierkonzepten und die Nutzung der Programmierumgebung ermittelt. Es wurden Auswirkungen auf das Lernen der Kinder und ihre Präferenzen für verschiedene Feedback-Merkmale ermittelt, was beispielsweise in elaborierten Hinweisen anstelle einfacher direkter Anweisungen resultiert. Auf der Grundlage dieser Ergebnisse wurde ein formatives Feedbackkonzept mit Hinweiskärtchen entwickelt und evaluiert. Dieses Konzept erwies sich als nützliche Strategie zur Unterstützung des Programmierunterrichts in der Grundschule durch formatives Feedback. KW - feedback KW - programming education KW - primary school education KW - Rückmeldung KW - Grundschulunterricht KW - Algorithmische Programmierung Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-15188 ER - TY - THES A1 - Welearegai, Gebrehiwet Biyane T1 - Precise Detection of Injection Attacks in Real-world Applications N2 - Code injection attacks like the one used in the high-profile 2017 Equifax breach, have become increasingly common, ranking at the top of OWASP’s list of critical web application vulnerabilities. The injection attacks can also target embedded applications running on processors like ARM and Xtensa by exploiting memory bugs and maliciously altering the program’s behavior or even taking full control over a system. Especially, ARM’s support of low power consumption without sacrificing performance is leading the industry to shift towards ARM processors, which advances the attention of injection attacks as well. In this thesis, we are considering web applications and embedded applications (running on ARM and Xtensa processors) as the target of injection attacks. To detect injection attacks in web applications, taint analysis is mostly proposed but the precision, scalability, and runtime overhead of the detection depend on the analysis types (e.g., static vs dynamic, sound vs unsound). Moreover, in the existing dynamic taint tracking approach for Java- based applications, even the most performant can impose a slowdown of at least 10–20% and often far more. On the other hand, considering the embedded applications, while some initial research has tried to detect injection attacks (i.e., ROP and JOP) on ARM, they suffer from high performance or storage overhead. Besides, the Xtensa has been neglected though used in most firmware-based embedded WiFi home automation devices. This thesis aims to provide novel approaches to precisely detect injection attacks on both the web and embedded applications. To that end, we evaluate JavaScript static analysis frameworks to evaluate the security of a hybrid app (JS & native) from an industrial partner, provide RIVULET – a tool that precisely detects injection attacks in Java-based real-world applications, and investigate injection attacks detection on ARM and Xtensa platforms using hardware performance counters (HPCs) and machine learning (ML) techniques. To evaluate the security of the hybrid application, we initially compare the precision, scalability, and code coverage of two widely-used static analysis frameworks—WALA and SAFE. The result of our comparison shows that SAFE provides higher precision and better code coverage at the cost of somewhat lower scalability. Based on these results, we analyze the data flows of the hybrid app via taint analysis by extending the SAFE’s taint analysis and detected a potential for injection attacks of the hybrid application. Similarly, to detect injection attacks in Java-based applications, we provide Rivulet which monitors the execution of developer-written functional tests using dynamic taint tracking. Rivulet uses a white-box test generation technique to re-purpose those functional tests to check if any vulnerable flow could be exploited. We compared Rivulet to the state-of-the-art static vulnerability detector Julia on benchmarks and Rivulet outperformed Julia in both false positives and false negatives. We also used Rivulet to detect new vulnerabilities. Moreover, for applications running on ARM and Xtensa platforms, we investigate ROP1 attack detection by combining HPCs and ML techniques. We collect data exploiting real- world vulnerable applications and small benchmarks to train the ML. For ROP attack detection on ARM, we also implement an online monitor which labels a program’s execution as benign or under attack and stops its execution once the latter is detected. Evaluating our ROP attack detection approach on ARM provides a detection accuracy of 92% for the offline training and 75% for the online monitoring. Similarly, our ROP attack detection on the firmware-only Xtensa processor provides an overall average detection accuracy of 79%. Last but not least, this thesis shows how relevant taint analysis is to precisely detect injection attacks on web applications and the power of HPC combined with machine learning in the control flow injection attacks detection on ARM and Xtensa platforms. Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-12926 ER - TY - JOUR A1 - Caspari-Sadeghi, Sima T1 - Artificial Intelligence in Technology-Enhanced Assessment: A Survey of Machine Learning JF - Journal of Educational Technology Systems N2 - Intelligent assessment, the core of any AI-based educational technology, is defined as embedded, stealth and ubiquitous assessment which uses intelligent techniques to diagnose the current cognitive level, monitor dynamic progress, predict success and update students’ profiling continuously. It also uses various technologies, such as learning analytics, educational data mining, intelligent sensors, wearables and machine learning. This can be the key to Precision Education (PE): adaptive, tailored, individualized instruction and learning. This paper explores (a) the applications of Machine Learning (ML) in intelligent assessment, and (b) the use of deep learning models in ‘knowledge tracing and student modeling’. The paper concludes by discussing barriers involved in using state-of-the-art ML methods and some suggestions to unleash the power of data and ML to improve educational decision-making. KW - artificial intelligence KW - knowledge tracing KW - machine learning KW - technology-enhanced assessment (TEA) Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-11818 SN - 0047-2395 SN - 1541-3810 VL - 51 IS - 3 SP - 372 EP - 386 PB - SAGE Publications CY - Sage CA: Los Angeles, CA ER - TY - JOUR A1 - Ghosh Dastidar, Kanishka A1 - Jurgovsky, Johannes A1 - Siblini, Wissam A1 - Granitzer, Michael T1 - NAG: neural feature aggregation framework for credit card fraud detection JF - Knowledge and Information Systems N2 - The state-of-the-art feature-engineering method for fraud classification of electronic pay-ments uses manually engineered feature aggregates, i.e., descriptive statistics of thetransaction history. However, this approach has limitations, primarily that of being dependenton expensive human expert knowledge. There have been attempts to replace manual aggre-gation through automatic feature extraction approaches. They, however, do not consider thespecific structure of the manual aggregates. In this paper, we define the novel Neural Aggre-gate Generator (NAG), a neural network-based feature extraction module that learns featureaggregates end-to-end on the fraud classification task. In contrast to other automatic featureextraction approaches, the network architecture of the NAG closely mimics the structureof feature aggregates. Furthermore, the NAG extends learnable aggregates over traditionalones through soft feature value matching and relative weighting of the importance of differ-ent feature constraints. We provide a proof to show the modeling capabilities of the NAG.We compare the performance of the NAG to the state-of-the-art approaches on a real-worlddataset with millions of transactions. More precisely, we show that features generated with theNAG lead to improved results over manual aggregates for fraud classification, thus demon-strating its viability to replace them. Moreover, we compare the NAG to other end-to-endapproaches such as the LSTM or a generic CNN. Here we also observe improved results. Weperform a robust evaluation of the NAG through a parameter budget study, an analysis of theimpact of different sequence lengths and also the predictions across days. Unlike the LSTMor the CNN, our approach also provides further interpretability through the inspection of itsparameters. KW - finance KW - credit card fraud KW - representation learning Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:101:1-2022060219175235764329 VL - 2022 IS - 64 SP - 831 EP - 858 PB - Springer Nature CY - Berlin ER - TY - THES A1 - Patil, Amit Dilip T1 - Towards Resilient Protection of Interconnected ICT and Power Systems N2 - Due to the increasing number of distributed renewable energy sources, the distribution grid faces new operational challenges. Information and Communication Technology (ICT) systems can resolve these challenges through grid services that use automation, monitoring, and real-time decision-making, helping maintain an acceptable operational state of the distribution grid. However, the reliance of the power system on the ICT system and vice versa in the so-called smart grid creates interdependencies between the systems, which present new pathways for failure propagation. Therefore, these interdependencies require special attention to ensure stable system operation in the face of these challenges. However, these interdependencies have not been studied extensively in the literature. This thesis investigates approaches to model, quantify and improve the performance and resilience of the smart grid infrastructure. The interdependencies are formalised as interconnectors, entities that exist in all the connected systems. These interconnectors consist of components from both systems, where the components are modelled as state variables. These state variables determine the interconnector state and the service delivered. Failures represented by a change in state variables may impact the state. These state variables are deployed in a discrete event simulation framework to determine the system performance over time. The simulation result is represented on a two-dimensional state-space diagram depicting the operational state and service delivered. This allows for the resilience analysis of a system under various scenarios. The interdependencies are further investigated by exploring the role of ICT-based grid services in power grids, whose state is defined based on ICT properties, such as latency. These properties are formalised using property graphs. The ICT properties obtained from these graphs are used to parameterise a finite state automaton model of a grid service states, which are then used to determine the state of the entire smart grid. Case studies of state estimation and adaptive protection highlight the application of this approach. The use of ICT in state estimation allows the distinction of a global and perceived view of the power grid, which influences decision-making in the face of challenges. This thesis further investigates the protection system in detail. The overcurrent protection system is adversely impacted by distributed generation, resulting in undesired phenomena such as protection blinding. This thesis characterises this phenomenon by proposing two indices that capture the protection trip time under the influence of distributed generation. These indices consider the electrical distance between faults, protection and distributed generation. These indices and simulation results identify the worst-impacted locations in the power grid in terms of protection trip time. They also identify fault locations under given assumptions that do not cause protection blinding. ICT can resolve protection blinding by adapting the sensitivity of protection relays. However, since faults must be cleared in a short timeframe, communication delays may adversely impact the fault-clearing time. A discrete event simulation model is proposed to study protection performance in distribution grids. Investigation of time distribution assumptions reveals that the lognormal distribution accurately captures the circuit breaker trip time. The impact of the distributed generation and communication delay on the protection system is determined by measuring fault-clearing times using discrete event simulation. Results show that for the system studied, protection blinding is critical for low impedance faults in grids with high fault levels, while high impedance faults are critical in grids with low fault levels. Moreover, sympathetic tripping is seen at increased distribution grid fault levels and fault impedance. Furthermore, while communication systems reduce fault clearing times, increased delays harm protection systems. Finally, communication system components like sensors can fail, preventing fault detection. This thesis proposes a genetic algorithm-based approach to optimally place redundant sensors, minimising protection blinding under communication uncertainty within a redundancy budget. Results demonstrate the algorithm's effectiveness in optimising redundant sensor locations, reducing system costs, and improving fault tolerance. For the system and scenarios investigated, an average of 60% redundant sensors are relocated, reducing the average protection trip time by 36.65% compared to a baseline approach that does not consider communication uncertainty. This encourages incorporating communication component failure considerations in power system planning. KW - information and communication technology KW - smart grid KW - discrete event simulation KW - property graphs KW - protection blinding KW - genetic algorithm Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-16088 ER - TY - JOUR A1 - Fritz, Manuela T1 - Temperature and non‐communicable diseases: Evidence from Indonesia's primary health care system JF - Health Economics N2 - Climate change induced rising temperatures will pose a detrimental threat to decent health in the coming decades. Especially at risk are individuals with chronic diseases, since heat can exacerbate a variety of health conditions. In this article, I examine the heat‐morbidity relationship in the context of Indonesia, focusing on chronic, non‐communicable diseases, namely diabetes, cardiovascular and respiratory diseases. Using a novel dataset from the Indonesian national health insurance scheme Jaminan Kesehatan Nasional/Badan Penyelenggara Jaminan Sosial (BPJS) and linking it with meteorological data on the daily‐district level, I estimate the causal effect of high temperatures on the daily number of primary health care visits. The results show that on a hot day all‐cause visits and visits with a diagnosis of diabetes and cardiovascular diseases increase by 8%, 25% and 14%, respectively. These increases are permanent and not offset by visit displacement or ‘harvesting’. Visits related to respiratory diseases seem not to be affected by high temperatures. I use several climate change scenarios to predict the increase in visits and costs by the end of the century, which all forecast a substantial financial burden for the health care system. These results might have relevance for other middle‐income countries with similar climatic conditions. KW - climate change KW - health KW - Indonesia KW - JKN/BPJS kesehatan KW - non‐communicable diseases KW - temperature Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-11429 VL - 31 IS - 11 SP - 2445 EP - 2464 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Fekih Hassen, Wiem A1 - Challouf, Maher T1 - Long short-term renewable energy sources prediction for grid-management systems based on stacking ensemble model JF - Energies N2 - The transition towards sustainable energy systems necessitates effective management of renewable energy sources alongside conventional grid infrastructure. This paper presents a comprehensive approach to optimizing grid management by integrating Photovoltaic (PV), wind, and grid energies to minimize costs and enhance sustainability. A key focus lies in developing an accurate scheduling algorithm utilizing Mixed Integer Programming (MIP), enabling dynamic allocation of energy resources to meet demand while minimizing reliance on cost-intensive grid energy. An ensemble learning technique, specifically a stacking algorithm, is employed to construct a robust forecasting pipeline for PV and wind energy generation. The forecasting model achieves remarkable accuracy with a Root Mean Squared Error (RMSE) of less than 0.1 for short-term (15 min and one day ahead) and long-term (one week and one month ahead) predictions. By combining optimization and forecasting methodologies, this research contributes to advancing grid management systems capable of harnessing renewable energy sources efficiently, thus facilitating cost savings and fostering sustainability in the energy sector. Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-14649 VL - 2024 IS - 17(13) ER - TY - THES A1 - Kravets-Meinke, Daria T1 - Search Engines and Foreign Influence: How Google and Yandex Mediate Russia’s Propaganda Abroad N2 - This cumulative dissertation examined how the US-based Google and Russia-based Yandex mediate the propaganda efforts of Russia’s ruling elites abroad on a case study of Belarus. The findings presented here contribute to a nuanced understanding of how algorithmic gatekeepers, particularly search engines, can be strategically appropriated or manipulated to reinforce and export state narratives beyond national borders. The main conclusion of this dissertation is that both Yandex and Google, albeit through different mechanisms and to varying extents, can serve as mediators of Russia’s propaganda efforts abroad. KW - search engines KW - Russia KW - propaganda Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-15953 ER - TY - JOUR A1 - Blanc, Julia A1 - Annekatrin, Meißner T1 - Towards a holistic approach to sustainable development : inner development as a missing link for sustainability transformation JF - Religions (Special issue "Sustainable development : the normative contribution of theology") N2 - The discourse on understanding and implementing sustainable development has so far focused primarily on the external aspects, neglecting the internal dimension of people. The main purpose of our paper is to contribute to addressing this research gap. Therefore, we intend to (1) substantiate existing aspects of the Inner Development Goals (IDGs), (2) complement them, and (3) link the concept of the IDGs to normative discourses in Christian Social Ethics and Social Philosophy. Our results show that the dimensions of Being, Relating, and Collaborating in the IDG Framework can be substantiated by the normative discourse on spirituality and by reference to the social principle of personality in Christian Social Ethics, as well as by the Indian Social Philosophical Perspective of Vimala Thakar which focuses on a value-based approach. This paper suggests that the concept of the IDGs will be strengthened by adding the dimension of Caring—understood as the concern and responsibility for the wholeness in the combining of the inner and outer dimensions. By linking the concept of the Inner Development Goals to the existing normative discourses in Christian Social Ethics and Social Philosophy, our research contributes to making the concept connectable and deepens the discussions on a practical and theoretical level. KW - holistic sustainable development KW - change of consciousness KW - being KW - caring KW - christian social ethics KW - social philosophy Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-15816 VL - 2025 IS - 16(1) PB - MDPI CY - Basel ER - TY - JOUR A1 - Fritz, Manuela A1 - Grimm, Michael A1 - Weber, Ingmar A1 - Yom-Tov, Elad A1 - Praditya, Benedictus T1 - Can social media encourage diabetes self-screenings? A randomized controlled trial with Indonesian Facebook users JF - npj | Digital medicine N2 - Nudging individuals without obvious symptoms of non-communicable diseases (NCDs) to undergo a health screening remains a challenge, especially in middle-income countries, where NCD awareness is low but the incidence is high. We assess whether an awareness campaign implemented on Facebook can encourage individuals in Indonesia to undergo an online diabetes self-screening. We use Facebook’s advertisement function to randomly distribute graphical ads related to the risk and consequences of diabetes. Depending on their risk score, participants receive a recommendation to undergo a professional screening. We were able to reach almost 300,000 individuals in only three weeks. More than 1400 individuals completed the screening, inducing costs of about US$0.75 per person. The two ads labeled “diabetes consequences” and “shock” outperform all other ads. A follow-up survey shows that many high-risk respondents have scheduled a professional screening. A cost-effectiveness analysis suggests that our campaign can diagnose an additional person with diabetes for about US$9. KW - Health care economics KW - Population screening KW - Risk factors Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-15157 VL - 2024 IS - 7 PB - Macmillan Publishers Limited CY - Basingstoke ER - TY - JOUR A1 - Hidalgo, Oliver Fernando T1 - The antinomian framework of Western and non-Western democracies — from theory to application JF - Frontiers in Political Science N2 - This article argues in favour of broadening the classical paradigm of democracy that historically emerged in the West. Without disregarding the undiminished significance of the idea of liberal democracy and its deep commitment to universal human rights, the necessity of a new accentuation of the concept of democracy is accepted in view of the observable democratic processes in non-Western societies. This should help to avoid both the blind spots of Eurocentrism and the misperception of countries as democracies that are merely masking their authoritarian or despotic character. The result is a theory of popular sovereignty that seeks to grasp and combine Western and non-Western conceptions of democracy in a balanced way and is based on a genealogical and comparative perspective of the history of political ideas in the global North and South. In a second step, the theory is then tested using a few selected examples (Confucian democracy, Islamic democracy, African democracy). KW - democracy KW - non-western history of political thought KW - confucianism KW - Muslim world KW - Africa Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-15821 VL - 2024 IS - 6 PB - Frontiers CY - Lausanne ER - TY - INPR A1 - Compaore, Georges A1 - Dabire, Bonayi Hubert A1 - Sangli, Gabriel A1 - Azianu, Komi Ameko A1 - Minoungou, Abdoul Kader A1 - Zoma, Vincent T1 - Analysis of the practices, structures and processes of translocal mobility systems in Burkina Faso BT - key findings from the MiTra|WA survey N2 - This report presents the results of the project “Migration and Translocality in West Africa (MiTra|WA)” with reference to translocal practices in Burkina Faso. Funded by the German Federal Ministry of Education and Research, the study ran from 2022 to 2024. The general objective of the project is to analyse the multiple links between the rural areas of departure and urban reception of migrants as well as the impacts on the development of these localities. The study employs a mixed-methods approach, combining quantitative and qualitative research methods. The quantitative component consisted of two types of surveys. First, a household survey in the migrants' area of origin (AoO) to identify the migrants’ belonging to these households. In the second phase, a telephone survey was conducted among migrants in the destination areas (AoD). Then, the focus was on socio-economic data as well as translocal interactions and network relationships. The qualitative component consisted of in-depth interviews with key actors in the different areas of departure and destination of migrants. These include migrants, local administrative officials, leaders of NGOs, associations, community and religious leaders. The results show that migration is a phenomenon experienced by many households in rural areas. There are as many internal migrants as there are international migrants. Of the 537 households surveyed, 405 (75.4%) have at least one migrant. The age structure of migrants shows a predominantly young structure of migrants (82% who are under 40 years old). According to gender, migration is strongly male-dominated (82%). Men are more inclined to international migration (56%). Female migration is precocious. A large proportion of migrants (41%) have no level of education and are mostly single (50%). Translocality, conceptualized in this study as the multifaceted links between the places of departure, transit and residence of migrants, is apprehended through telephone contacts between migrants and their place of origin, in addition to the different forms of mobility: mobility of people, financial resources (remittances), material resources (transfers in kind), intangible resources (ideas, practices, etc.). Exchanges are often bidirectional. Telephone contacts represent 86% of migrants. Migrants visit the household in the area of origin more frequently (41.8%) than they receive household members at their destination (33.9%). More than 66.6% of migrants transfer remittances to their households in rural areas. With regard to the 4-level translocality intensity indicator (Wehner 2022), it can be concluded that over 50% of migrants are located at the two highest levels. Hence, translocality is an important feature of rural-urban migration in Burkina Faso. T3 - Migration, translocality and development in times of climate change. Mitra|WA Working Paper Series - 6 KW - migration KW - translocality KW - translocal practices KW - Burkina Faso Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-15862 IS - 6 ER - TY - JOUR A1 - Thir, Veronika T1 - Co-text, context, and listening proficiency as crucial variables in intelligibility among nonnative users of English JF - Studies in Second Language Acquisition N2 - Research on intelligibility in international encounters has long focused on issues of pronunciation to the detriment of factors such as linguistic co-text and extralinguistic context, which are comparatively well-studied variables in intelligibility research concerning L1 listeners. This paper seeks to expand the scope of international intelligibility research in this respect by reporting on a large-scale study involving 423 nonnative listeners at different proficiency levels, who transcribed words spoken with another nonnative accent under four conditions that varied in the availability of syntactic, semantic, and schematic cues. The results suggest that co-text and context as well as listening proficiency are crucial variables that ought to receive greater attention in research on international intelligibility. The pedagogical implications of these findings are addressed as well. Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-16374 VL - 45 IS - 5 SP - 1210 EP - 1231 PB - Cambridge University Press CY - Cambridge ER - TY - RPRT A1 - Jäckel, Franziska A1 - Haberger, Mathias T1 - The stone-made myth of return : translocality and housing in Amedzofe, Ghana N2 - This paper delves into how migration and the resulting emergence of translocal networks, shaped by migrants' spatial and social trajectories, influence housing investment decisions in the area of origin. During our field stay in Amedzofe, a settlement in south-eastern Ghana, we gathered qualitative data in a transect walk with a local key informant and, building upon this, ten semi-structured interviews, alongside quantitative data collected through a questionnaire involving 94 households as part of the broader data collection within the MiTra|WA research project. By applying a simple propensity score matching approach, the study demonstrates that households with at least one migrant are 18 percentage points more likely to invest in housing for Amedzofe family members than non-migrant housholds. Notably, investments in aesthetically appealing housing are particularly significant. Our qualitative findings substantiate these observations, highlighting a strong inclination to showcase translocal interconnectedness and a lasting sense of belonging to Amedzofe. Housing investments also encapsulate the ingrained notion of migrants' eventual return to Amedzofe, especially for retirement, namely the "stone-made myth of return." Our study emphasizes the need for expanded research focus on translocal networks and the symbolic importance of housing in the Ghanaian context. Understanding these dynamics is crucial for addressing the implications of growing demands for living space, which may impact land distribution and require further investigation. T3 - Migration, translocality and development in times of climate change. Mitra|WA Working Paper Series - 4 KW - migration KW - translocal network KW - housing investment Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-15301 IS - 4 ER - TY - JOUR A1 - Kaiser, Tobias T1 - Growth of log-analytic functions JF - Archiv der Mathematik N2 - We show that unary log-analytic functions are polynomially bounded. In the higher dimensional case, globally a log-analytic function can have exponential growth. We show that a log-analytic function is polynomially bounded on a definable set which contains the germ of every ray at infinity. KW - Log-analytic functions KW - Polynomially bounded KW - Exponential growth Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:101:1-2023091614564557203657 VL - 120 IS - 6 SP - 605 EP - 614 PB - Springer Nature CY - Berlin ER - TY - JOUR A1 - Felfeli, Anna A1 - Stahl, Bernhard T1 - Mutual desecuritization as a model of détente? Foreign policy change in the US-Cuban dyad JF - Zeitschrift für Friedens- und Konfliktforschung N2 - In foreign policy dyads characterized by enmity, mutual desecuritization can serve as a crucial asset for détente. But how does “the way out of the emergency mode” function, considering mutual securitizations over decades? Embarking from theoretical insights provided by second generation scholars on securitization and desecuritization studies, the authors generate a theory-based model of détente for dyads. This analytical tool contributes to the study of the dissolution of historically grown, mutual (re-)securitization processes in interstate relations. By clarifying the impact and functioning of the four desecuritizing modes (replacement, silencing, change through stabilization, and rearticulation), our model allows us to trace dynamics of change and assess the sustainability of détente. Especially mutual desecuritization as rearticulation has the potential to substantially change the self-other relation with effects on the social structure of a foreign policy dyad. The heuristic case study of US-Cuban relations serves as a prime example of a complex dyad of enmity which became a subject of change due to the Obama–Castro diplomacy in 2014. The study on US-Cuban foreign policy issues before and after 2014 helps to sharpen our understanding of dynamic securitization and desecuritization processes. The overall analysis demonstrates that the modes of desecuritization during the Obama–Castro diplomacy lifted the process of détente to a new and unprecedented level. KW - Securitization theory KW - Modes of desecuritization KW - Overcoming enmity KW - Rearticulation KW - Change through stabilization Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:101:1-2023110610482836615655 VL - 12 IS - 1 SP - 59 EP - 86 PB - Springer Nature CY - Berlin ER - TY - JOUR A1 - Klumpp, Lorenz T1 - Exploring the distinction between populism through and by the media from a visual perspective: representations of German politicians on magazine covers of Der Spiegel and Compact JF - Visual Communication N2 - By drawing on a communication-based approach to populism, this article argues that populism research should put more emphasis on the performative and stylistic dimension of the phenomenon, including its visual elements, in different media formats. The study theoretically refers to the distinction of populism through and by the media, which has been discussed to a great extent in populist political communication research. Empirically, the author focuses on visual representations of politicians on the covers of the German news weekly Der Spiegel as well as those of Compact – a far-right alternative magazine. The article argues that political magazines contribute to how the political is imagined, particularly by the visual messages they convey via their front pages. An image type analysis of both magazines’ covers between 2010 and 2020 is conducted (N = 103) in order to explore patterns in the visual representations of German politicians disseminated by the magazines. On the one hand, the comparison of a mainstream and far-right alternative medium enriches the theoretical debate of how populism is strengthened by opportunity structures through the media. On the other hand, the issue of how populism is actively promoted by the media is addressed. KW - alternative media KW - iconographic-iconological analysis KW - image type analysis KW - magazine covers KW - mainstream media KW - media populism KW - populism Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-16450 VL - 24 IS - 1 SP - 148 EP - 177 PB - Sage CY - Thousand Oaks ER - TY - JOUR A1 - Adiatu, Afeez T1 - Energizing the inter-regional cooperation and energy governance : an exploration of the Africa-EU energy partnership JF - Journal of Sustainable Development of Energy, Water and Environment Systems (ISSN: 1848-9257, DOI: 10.13044/j.sdewes) N2 - The emergence of change in the global energy governance structure is precipitated by the shift in global energy technology. The shift from carbon-intense energy to cleaner sources surpasses technological discontinuation. The inter-regional, regional, and sub-regional grouping emerged in global energy governance to support governance capabilities across countries. This research seeks to investigate the inter-regional partnership between Africa and the European Union initiated to facilitate energy decision-making. This study adopts thematic analysis to explore literature and reports on the Africa-EU partnership to understand its impact on the future of the African energy sector. This research argues using a neo-liberal lens that the limited state capacity in energy governance may necessitate inter-regional partnerships to aid energy sector development in Africa. The study concludes that considering Africa's potential in renewable energy sources such as solar irradiation and the limited energy access in the Sub-Saharan region, intervention of external capabilities through technological and financial aids may stimulate the utilization of such potential. KW - global energy governance KW - renewable energy KW - energy transition KW - regionalism KW - global governance Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-15782 VL - 2024 IS - 12(4) PB - SDEWES Centre CY - Zagreb ER - TY - GEN A1 - Ungruhe, Christian T1 - Football Migration from Africa T2 - Bundeszentrale für politische Bildung: Policy Briefs N2 - Many male and female African footballers strive for a career in leagues on other continents. How has African football migration developed over time? Where do players move? Which risks do they face? KW - Football KW - Migration KW - Africa Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-14849 N1 - First published by Bundeszentrale für politische Bildung (Bonn) as a Policy Brief under https://www.bpb.de/themen/migration-integration/kurzdossiers/549281/football-migration-from-africa/ ER - TY - THES A1 - Wild, Matthias T1 - A statistical perspective on machine learning: three essays on improvement, application and interpretation of predictive algorithms N2 - In this thesis we address a series of topics at the interface between statistics and machine learning. This includes the improvement of predictive algorithms using statistical concepts, potential and challenges in the application of predictive algorithms in areas traditionally covered by statistical theory, and the interpretation of black-box algorithms by means of statistical hypothesis testing. KW - machine learning KW - hypothesis test KW - statistical learning KW - boosting KW - random forest Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-15311 ER - TY - JOUR A1 - Nahr, Nora A1 - Heikkilä, Marikka T1 - Uncovering the identity of Electronic Markets research through text mining techniques JF - Electronic Markets N2 - As an established academic journal in the e-commerce and digital platforms fields, Electronic Markets (EM) features a diverse range of topics and occupies a significant role in the information systems field. The study investigates EM’s topic diversity over the time period 2009–2020 using a text mining analysis and a bibliometric analysis and identifies 28 cluster groups.The analysis reveals that the top three topics are 1) service quality, 2) blockchain and other shared trust building solutions,their impact and credibility, as well as 3) consumer buying behavior and interactions. EM's core identity lies in a balanced set of core themes that bring technological, business or human/ social perspectives to the research of networked business and digital economy. This includes research on digital and smart services, applications, consumer behavior and business models,as well as technology and e-commerce data. Ethical and sustainability related topics are however still less present in EM. KW - Core identity KW - Text mining analysis KW - Cluster analysis KW - Unsupervised machine learning KW - Bibliometric analysis Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:101:1-2022083023490559933318 VL - 2022 IS - 32 SP - 1257 EP - 1277 PB - Springer Nature CY - Berlin ER - TY - JOUR A1 - von Ditfurth, Lukas A1 - Lienemann, Gregor T1 - The Data Governance Act: – Promoting or Restricting Data Intermediaries? JF - Competition and Regulation in Network Industries N2 - Following its approval by the European Parliament in April 2022, the Data Governance Act (DGA) is the first legislative instrument announced in the European Data Strategy to come into force. Aimed at facilitating the re-use and sharing of data in and between the private and public sectors, the DGA introduces regulation for a newly emerging type of digital platforms – the so-called “providers of data intermediation services”. In order to offer their services on the market, providers will have to submit to a prior notification procedure and show compliance with several conditions placed on their economic activities. The regulation of data intermediaries is intended to increase their trustworthiness and ensure the competitiveness of the markets in which they operate. Recent experiences with digital platforms have shown the potential of intermediaries to organise and facilitate markets. At the same time, digital platforms pose undeniable risks to their users and markets at large. Against this backdrop, the role of data intermediaries as envisioned by the DGA must be examined carefully before turning to the question whether the DGA can achieve competitive and trustworthy data sharing through registered third parties. This paper intends to shed light on these and other issues by examining, in-depth, the chapter in the DGA dedicated to data intermediaries (Art. 10–15) from a legal, policy and competition economics perspective. In particular, this paper explores how the experiences made with large-scale digital platforms have shaped the DGA. Thereby, this paper aims to contribute towards a holistic understanding of these provisions as a basis for an informed discussion on the legal framework and on possible alternatives. KW - Data Governance Act KW - Data Intermediaries KW - Data Law Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-11483 SN - 1783-5917 SN - 2399-2956 VL - 23 IS - 4 SP - 270 EP - 295 PB - SAGE Publications CY - London ER - TY - JOUR A1 - Knott, Manuel A1 - Strich, Franz A1 - Strunk, Kim Simon A1 - Mayer, Anne-Sophie T1 - Uncovering potential barriers of using initial coin offerings to finance artistic projects JF - Journal of Cultural Economics N2 - Artists make vital contributions to our society and lay the foundations for billion-dollar industries. However, these artists consistently struggle to acquire sufficientfunding for their projects and their livelihood. New technology-supported possibili-ties for funding artists and their projects have emerged in recent years. Initial CoinOffering (ICO) is a novel form of reward-based tokenized crowdfunding. AlthoughICOs are promising as a way to fund artistic projects, they lack widespread adoptionin the creative and cultural industry (CCI). Based on 35 qualitative in-depth inter-views, we identify four barriers that hinder the funding of artistic projects throughICOs: legal shortcomings, investment restrictions, lack of consumer interest, andintermediaries’ resistance. Our research contributes to cultural finance and fundingliterature by disclosing barriers that impede a promising form of financing artisticprojects. Further, we outline possible solutions to overcome them. We also con-tribute to the research about ICOs by showing that rather than reducing investmentrisks, these offerings merely shift them. KW - initial coin offerings KW - blockchain technology KW - cultural finance KW - artists KW - creative and cultural industries KW - barriers Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:101:1-2022081518483651137386 VL - 2022 IS - 46 SP - 317 EP - 344 PB - Springer Nature CY - Berlin ER - TY - JOUR A1 - Beierl, Stefan A1 - Dodlova, Marina T1 - Public Works Programmes and Cooperation for the Common Good: Evidence from Malawi JF - The European Journal of Development Research N2 - This paper investigates the relationship between Malawi’s largest and oldest publicworks programme (PWP) and social cohesion, specifically within-community coop-eration for the common good. Using both primary and secondary data, we show thatpublic works are associated with higher coordination activities and higher voluntary(unpaid) contributions to public goods, along both vertical ties (between communitymembers and local leaders) and horizontal ties (among community members). Espe-cially for school-building activities, voluntary inputs in the form of labour and otherin-kind contributions are higher in the presence of the PWP. Our results contrib-ute to a better understanding of the link between social protection programmes withcommunity-driven features and social cohesion. KW - Public works KW - Cash-for-work KW - Social protection KW - Cooperation for the common good KW - Coordination KW - Community meeting KW - Voluntary contributions Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:101:1-2022080712061894426936 VL - 2022 IS - 34 SP - 1264 EP - 1284 PB - Springer Nature CY - Berlin ER - TY - JOUR A1 - Adam, Marc T. P. A1 - Krämer, Jan T1 - Evaluating the emotional bidding framework: new evidence from a decade of neurophysiology JF - Electronic Markets N2 - Ten years ago the “emotional bidding framework” (Adam et al., Electronic Markets, 21(3), 197–207, 2011b) was published in this journal. It provided a conceptualization for the role of human emotion in electronic auctions along six propositions on how emotions emerge during the auction process and affect auction outcomes. While the framework emphasized the importance of immediate emotional responses and momentary changes in the bidders’ emotional state, the original articledid not include an evaluation of its propositions given the limited data on how bidders experience emotions in the moment that they occur. Ten years on, advances in the growing research field of NeuroIS allow to evaluate the propositions based on neurophysiological evidence. As a rejoinder of the original article, the present paper synthesizes these insights, refines the framework further, and identifies fruitful areas for future research based on remaining gaps in the body of knowledge. KW - Auctions KW - Auction Fever KW - NeuroIS Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:101:1-2022080421114680906980 VL - 2022 IS - 32 SP - 1529 EP - 1540 PB - Springer Nature CY - Berlin ER - TY - JOUR A1 - Wolff, Hannes T1 - Patentability of brain organoids derived from iPSC : a legal evaluation with interdisciplinary aspects JF - Neuroethics N2 - Brain Organoids in their current state of development are patentable. Future brain organoids may face some challenges in this regard, which I address in this contribution. Brain organoids unproblematically fulfil the general prerequisites of patentability set forth in Art. 3 (1) EU-Directive 98/44/EC (invention, novelty, inventive step and susceptibility of industrial application). Patentability is excluded if an invention makes use of human embryos or constitutes a stage of the human body in the individual phases of its formation and development. Both do not apply to brain organoids, unless ES-cells are used. Art. 6 (1) EU-Directive 98/44/EC excludes patentability for inventions “the commercial exploitation of which would be contrary to ordre public or morality”. While there is no conceivable scenario, in which the commercial application of current brain organoids violates the ordre public , the same is not necessarily true for future brain organoids. Keeping in mind that a development of consciousness-like abilities in future brain organoids cannot be excluded and that an ability for both physical and psychological suffering has been theorized, both of which are aspects of the ordre public , certain applications of future brain organoids may constitute a violation of the ordre public and therefore lead to an exclusion of patentability. KW - Patentability KW - Law KW - Brain organoids KW - Consciousness KW - Moral status Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:101:1-2024033111323821449698 SN - 1874-5490 SN - 1874-5504 VL - 17 IS - 1 PB - Springer Netherlands CY - Dordrecht ER - TY - JOUR A1 - Kaiser, Tobias T1 - Periods, power series, and integrated algebraic numbers JF - Mathematische Annalen N2 - Periods are defined as integrals of semialgebraic functions defined over the rationals. Periods form a countable ring not much is known about. Examples are given by taking the antiderivative of a power series which is algebraic over the polynomial ring over the rationals and evaluate it at a rational number. We follow this path and close these algebraic power series under taking iterated antiderivatives and nearby algebraic and geometric operations. We obtain a system of rings of power series whose coefficients form a countable real closed field. Using techniques from o-minimality we are able to show that every period belongs to this field. In the setting of o-minimality we define exponential integrated algebraic numbers and show that exponential periods and the Euler constant is an exponential integrated algebraic number. Hence they are a good candiate for a natural number system extending the period ring and containing important mathematical constants. KW - algebraic geometry KW - algebraic topology KW - algebra KW - associative rings and algebras KW - commutative rings and algebras KW - number theory Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:101:1-2024040910285674698609 SN - 0025-5831 SN - 1432-1807 VL - 390 IS - 2 SP - 2043 EP - 2074 PB - Springer Berlin Heidelberg CY - Berlin/Heidelberg ER - TY - JOUR A1 - Narh, John T1 - Progress, challenges and prospects of the modified Taungya system in Ghana JF - Agroforestry Systems N2 - Forest landscape restoration through agroforestry has been implemented as a Nature-based Solution to deforestation in the Global South with varied outcomes. The Modified Taungya System (MTS) is one of such programmes introduced in Ghana to address socio-economically-induced degradation of forest reserves. For two decades since its establishment, there has not been any examination of  a synthesised findings on the MTS and their implication for the prospects of the programme. Using the PRISMA method to select empirical studies, this article examines the state of reforestation under the MTS by reflecting on the conditions of success and failures of the programme. In doing so, two interrelated arguments are advanced. First, the MTS seems to be successful when farmers are well-educated about the programme and their future benefits in the reserves that they enrich. Second, the MTS has largely failed to achieve its full potentials for forest recovery due to bribery, corruption and nepotism that have bedevilled land demarcation to, and delays in signing benefit sharing agreement with, farmers. There is a need for a thorough sensitisation on the MTS to enhance its transparency. Besides, the MTS needs to be remodified if it would be one of the strategies to contribute to the Bonn Challenge and for a durable climate mitigation. KW - Agroforestry KW - Bioeconomy KW - Climate change KW - Mitigation KW - Modified taungya system KW - Nature-based solution Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:101:1-2405100928309.284032809350 SN - 0167-4366 SN - 1572-9680 VL - 98 IS - 3 SP - 767 EP - 782 PB - Springer Netherlands CY - Dordrecht ER - TY - THES A1 - Knott, Manuel T1 - Blockchain: Disrupting the Creative Industries – Enablers, Barriers and Utilization through Persuasive System Design N2 - Blockchain technology enables the automated recording of information and execution of contract content – utilizing so-called Smart Contracts – without relying on trusted intermediaries (Beck et al., 2016). A blockchain is best described as a decentralized digital ledger (Atzori, 2015). The decentralized data storage on the blockchain makes the recorded information tamper-proof and creates transparency along the value chain. Therefore blockchain changes fundamentally the way data and information are processed (Al-Jaroodi & Mohamed, 2019; Avital et al., 2016). This has given rise to numerous use cases for blockchain in a wide range of industries. Fundamentally, blockchain technology can be used at any time when information needs to be stored in an automated and tamper-proof manner (Crosby et al., 2016). In the financial industry, blockchain helps to automate peer-to-peer transactions. This makes middlemen obsolete, which can reduce transaction costs (Cai, 2018). In the public health sector, blockchain is primarily used for decentralized storage of patient records. By using blockchain technology, these patient records are secured against manipulation and unauthorized access by third parties (Mettler, 2016). Another interesting use case can be seen in the electricity market. Blockchain technology makes it possible to integrate micro producers of electricity, such as private households, into the power grid in a cost-efficient way (Cheng et al., 2017). However, blockchain technology also offers several applications in the creative industries to support the daily work of professionals. The term creative industries encompasses industries and sectors which hold intellectual property at the core of their value creation (Caves, 2000). According to DCMS (1998),creative industries include not only classic art sectors such as fine art, painting or crafting, but also areas such as marketing, game developing, film and video or music. As the main drivers of innovation, the creative industries have a steadily increasing influence on the overall economic impact. Often, ideas, products and services from the creative industries ultimately flow into other areas, such as the automotive sector, and support them in achieving their entrepreneurial goals (Banks, 2010; Jones et al., 2004). In order to continuously maintain the position as an innovation driver, a certain form of organization has prevailed in the creative industries. For the creative industries to react flexibly to new requirements and a constantly changing environment, work is usually carried out as project-based (DeFillippi, 2015). For this purpose, the teams of the project-based organization are predominantly formed using freelancers who are specialists in the required field. As a result, many recurring organizational activities arise, such as contracting, team finding or onboarding (DeFillippi, 2015; Eikhof & Haunschild, 2006). Therefore, professionals from the creative industries have to spend significant time on activities that do not serve their core task of creating intellectual property. These tasks not only reduce the efficiency of their work, but also hinder their creative flow (Foord, 2009; Hennekam & Bennett, 2016). In this regard, blockchain represents a promising technology to support professionals in the creative industries. For the creative industries, blockchain is primarily used to automate formal processes and secure intellectual property rights (O’Dair, 2018). Blockchain technology enables artists and creatives more freedom for their own creative activities. By automating repetitive activities, professionals from the creative industries are freed from typical management tasks (Arcos, 2018; Cong & He, 2019). Furthermore, for the first time, intellectual property can be secured in a cost- and time-efficient way by utilizing blockchain technology. This is made possible by the decentralized nature of the blockchain, which makes subsequent manipulation of the contents of the intellectual property impossible (Avital et al., 2016; Beck et al., 2016; Regner et al., 2019). Ultimately, the use of so-called Non-Fungible Tokens (NFTs) create the opportunity for artists and creatives to sell unique digital art (Regner et al., 2019). Thus, blockchain generates entirely new ways for creative industries to organize their projects and opens new markets to sell their work. While several use cases of blockchain technology can be identified in the creative industries, the widespread use of blockchain is still lacking. So far, no Blockchain service or blockchain application has managed to take a dominant market position in the creative industries. At first sight, this seems surprising since artists and creatives could fundamentally benefit from this technology. At the same time, professionals from the creative industries would not be dependent on middlemen or central entities. This circumstance gave the impulse for the research presented in this thesis. I was able to identify that professionals from the creative industries are still underutilizing blockchain technology for three main reasons: (1) When using blockchain technology, professionals from the creative industries experience strong resistance from their stakeholders, who want to prevent the use of blockchain. (2) The perceived constraints by artists and creatives in using blockchain still deter many from using this technology extensively. (3) Several blockchain applications lack a persuasive design, resulting in many artists and creatives continue to prefer conventional services and products. KW - Blockchain, Creative Industries, DLT, Persuasive Design Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-11149 ER - TY - THES A1 - Qiu, Ruyi T1 - The Role of Context in Stimulus-Response Binding and Retrieval N2 - Feature binding has been proven to be a common and general mechanism underlying human information processing and action control. There is strong evidence showing that when humans perform a task, stimuli (e.g., the target, the distractor) and responses are bound together into an episodic representation, called an event file or a stimulus-response (S-R) episode, which can be retrieved upon feature repetition. As compared with the target and the distractor, the context (i.e., an additional stimulus presented together with the target and the distractor, but not associated with any response keys throughout the whole course of the task), which is considered as task-irrelevant, did not receive that much attention in previous studies. The current thesis was aimed to provide insights into the different roles the context plays in S-R binding and retrieval. Specifically, in Study One and Two, the role of context as an element that can be integrated into an S-R episode was investigated, with a focus on the saliency and the inter-trial variability of the contextual stimulus. Both properties were found to influence how the context is integrated into an S-R episode. More specifically, results show that both saliency and inter-trial variability determine whether the context is directly bound in a binary fashion with the response, or it enters in to a configural binding together with another stimulus and the response. In Study Three, intrigued by the role of context as an event segmentation factor in the event perception literature, whether the context can demarcate the integration window of an S-R episode was tested. Results provide consistent evidence that sharing a common context leads to a stronger binding between a stimulus and the response, as compared with the condition when these elements are separated by different contexts, thereby suggesting a binding principle of common context. Taken together, the current thesis specifies the role of context in S-R binding and retrieval, and sheds some light on how contextual information influences human behavior. Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-11390 ER - TY - THES A1 - Liang, Hanning T1 - Deflectometric Measurement of the Topography of Reflecting Freeform Surfaces in Motion N2 - Measuring the topography of specular surfaces with strong surface structures in motion was impossible before this research. A new method based on singleshot phase-measuring de ectometry (SSPMD) and combining different solution aspects has been presented. Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-11672 ER - TY - JOUR A1 - Becher, Stefan A1 - Gerl, Armin ED - Sarne, Giuseppe Maria Luigi ED - Ma, Jianhua ED - Rosaci, Domenico ED - Srivastava, Gautam T1 - ConTra Preference Language: Privacy Preference Unification via Privacy Interfaces JF - Sensors N2 - After the enactment of the GDPR in 2018, many companies were forced to rethink their privacy management in order to comply with the new legal framework. These changes mostly affect the Controller to achieve GDPR-compliant privacy policies and management.However, measures to give users a better understanding of privacy, which is essential to generate legitimate interest in the Controller, are often skipped. We recommend addressing this issue by the usage of privacy preference languages, whereas users define rules regarding their preferences for privacy handling. In the literature, preference languages only work with their corresponding privacy language, which limits their applicability. In this paper, we propose the ConTra preference language, which we envision to support users during privacy policy negotiation while meeting current technical and legal requirements. Therefore, ConTra preferences are defined showing its expressiveness, extensibility, and applicability in resource-limited IoT scenarios. In addition, we introduce a generic approach which provides privacy language compatibility for unified preference matching. KW - privacy KW - preference language KW - legal factors KW - GDPR KW - usability Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-11218 SN - 1424-8220 VL - 22 IS - 14 PB - MDPI CY - Basel, Switzerland ER - TY - THES A1 - Lachat, Paul T1 - Detecting Inference Attacks Involving Sensor Data N2 - The collection of personal information by organizations has become increasingly essential for social interactions. Nevertheless, according to the GDPR (General Data Protection Regulation), the organizations have to protect collected data. Access Control (AC) mechanisms are traditionally used to secure information systems against unauthorized access to sensitive data. The increased availability of personal sensor data, thanks to IoT-oriented applications, motivates new services to offer insights about individuals. Consequently, data mining algorithms have been proposed to infer personal insights from collected sensor data. Although they can be used for genuine purposes, attackers can leverage those outcomes, combining them with other type of data, and further breaching individuals’ privacy. Thus, bypassing AC mechanisms thanks to such insights is a concrete problem. We propose an inference detection system based on the analysis of queries issued on a sensor database. The knowledge obtained through these queries, and the inference channels corresponding to the use of data mining algorithms on sensor data to infer individual information, are described using Raw sensor data based Inference ChannEl Model (RICE-M). The detection is carried out by RICE-M based inference detection System (RICE-Sy). RICE-Sy considers at the time of the query, the knowledge that a user obtains via a new query and has obtained via his query history, and determines whether this is sufficient to allow that user to operate a channel. Thus, privacy protection systems can take advantage of the inferences detected by RICE-Sy, taking into account individuals’ information obtained by the attackers via a database of sensors, to further protect these individuals. Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-14149 ER - TY - JOUR A1 - Narh, John A1 - Wehner, Stefanie A1 - Ungruhe, Christian A1 - Eberth, Andreas T1 - The role of translocal practices in a natural climate solution in Ghana JF - Climate N2 - People-centred reforestation is one of the ways to achieve natural climate solutions. Ghana has established a people-centred reforestation programme known as the Modified Taunya System (MTS) where local people are assigned degraded forest reserves to practice agroforestry. Given that the MTS is a people-centred initiative, socioeconomic factors are likely to have impact on the reforestation drive. This study aims to understand the role of translocal practices of remittances and visits by migrants on the MTS. Using multi-sited, sequential explanatory mixed methods and the lens of socioecological systems, the study shows that social capital and socioeconomic obligations of cash remittances from, as well as visits by migrants to their communities of origin play positive roles on reforestation under the MTS. Specifically, translocal households have access to, and use remittances to engage relatively better in the MTS than households that do not receive remittances. This shows that translocal practices can have a positive impact on the environment at the area of origin of migrants where there are people-centred environmental policies in place. KW - agroforestry KW - multi-sited research KW - reforestation KW - remittances KW - sequential explanatory mixed methods KW - socioecological systems Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-14138 VL - 2023 IS - 11 PB - MDPI CY - Basel ER - TY - THES A1 - Mosch, Philipp T1 - Four Essays on Digital Transformation Strategies from the Perspectives of Capital Markets, Incumbents and Start-ups N2 - This dissertation uses four studies to examine the context-contingent strategic factors that are critical to the success of digital transformation strategies from the perspectives of capital markets, incumbents, and start-ups. It focuses on a better understanding of (1) digital innovations and their quantitative evaluation, (2) power disruptions in digitally servitized supply chains, (3) strategic measures and dynamics in digital B2B platform markets, and (4) strategizing by data-driven start-ups in digitalized business networks. Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-11337 ER - TY - THES A1 - Schlenker, Florian T1 - Delaunay Configuration B-Splines N2 - The generalization of univariate splines to higher dimensions is not straightforward. There are different approaches, each with its own advantages and drawbacks. A promising approach using Delaunay configurations and simplex splines is due to Neamtu. After recalling fundamentals of univariate splines, simplex splines, and the wellknown, multivariate DMS-splines, we address Neamtu’s DCB-splines. He defined two variants that we refer to as the nonpooled and the pooled approach, respectively. Regarding these spline spaces, we contribute the following results. We prove that, under suitable assumptions on the knot set, both variants exhibit the local finiteness property, i.e., these spline spaces are locally finite-dimensional and at each point only a finite number of basis candidate functions have a nonzero value. Additionally, we establish a criterion guaranteeing these properties within a compact region under mitigated assumptions. Moreover, we show that the knot insertion process known from univariate splines does not work for DCB-splines and reason why this behavior is inherent to these spline spaces. Furthermore, we provide a necessary criterion for the knot insertion property to hold true for a specific inserted knot. This criterion is also sufficient for bivariate, nonpooled DCB-splines of degrees zero and one. Numerical experiments suggest that the sufficiency also holds true for arbitrary spline degrees. Univariate functions can be approximated in terms of splines using the Schoenberg operator, where the approximation error decreases quadratically as the maximum distance between consecutive knots is reduced. We show that the Schoenberg operator can be defined analogously for both variants of DCB-splines with a similar error bound. Additionally, we provide a counterexample showing that the basis candidate functions of nonpooled DCB-splines are not necessarily linearly independent, contrary to earlier statements in the literature. In particular, this implies that the corresponding functions are not a basis for the space of nonpooled DCB-splines. N2 - Univariate Splines können nicht unmittelbar auf mehrere Dimensionen verallgemeinert werden. Jedoch gibt es verschiedene Ansätze mit jeweils unterschiedlichen Vor- und Nachteilen. Eine vielversprechende Herangehensweise, die Delaunay-Konfigurationen und Simplex-Splines verwendet, stammt von Neamtu. Nachdem wir die Grundlagen von univariaten Splines, Simplex-Splines und den bekannten multivariaten DMS-Splines wiederholt haben, beschäftigen wir uns mit Neamtus DCB-Splines. Er führte zwei verschiedene Varianten ein, die als nichtaggregierter beziehungsweise aggregierter Ansatz bezeichnet werden. In Bezug auf diese Splineräume präsentieren wir die folgenden Ergebnisse. Wir zeigen zum einen, dass beide Varianten unter geeigneten Voraussetzungen an die Knotenmenge die sogenannte Lokale-Endlichkeits-Eigenschaft besitzen. Dies bedeutet, dass die Splineräume lokal endlichdimensional sind und dass an jedem Punkt nur eine endliche Anzahl der Kandidaten an Basisfunktionen einen von null verschiedenen Wert aufweist. Zusätzlich ermitteln wir ein Kriterium, welches diese Eigenschaften auf einem kompakten Gebiet auch unter schwächeren Voraussetzungen garantiert. Darüber hinaus zeigen wir, dass der von den univariaten Splines her bekannte Prozess des Knoteneinfügens für DCB-Splines nicht funktioniert, und begründen, warum dieses Verhalten in der Natur dieser Splineräume liegt. Außerdem geben wir ein notwendiges Kriterium dafür an, dass die Knoteneinfüge-Eigenschaft für einen bestimmten einzufügenden Knoten gegeben sein kann. Für bivariate nicht-aggregierte DCB-Splines von Grad null und eins ist dieses Kriterium auch hinreichend. Numerische Experimente legen ferner die Vermutung nahe, dass dies unabhängig vom Splinegrad der Fall ist. Univariate Funktionen können mithilfe des Schoenberg-Operators durch Splines approximiert werden. Dabei hat eine Verringerung des maximalen Abstands zweier aufeinanderfolgender Knoten eine quadratische Verringerung des Approximationsfehlers zur Folge. Wir zeigen, dass der Schoenberg-Operator für beide Variaten von DCB-Splines auf analoge Art und Weise und mit einer ähnlichen Fehlerschranke definiert werden kann. Zusätzlich geben wir ein Gegenbeispiel an, das zeigt, dass die Basisfunktions-Kandidaten der nicht-aggregierten DCB-Splines nicht notwendigerweise linear unabhängig sind, was einen Gegensatz zu früheren Behauptungen in der Literatur darstellt. Dies impliziert insbesondere, dass die entsprechenden Funktionen keine Basis für den Raum der nicht-aggregierten DCB-Splines bilden. KW - Multivariate splines KW - Simplex splines KW - Delaunay triangulations KW - Delaunay configurations KW - Neamtu, Marian KW - Spline KW - Bivariater Spline KW - Spline-Raum KW - Simplexspline KW - Neamtu, Marian Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-11225 ER - TY - THES A1 - Mini, Tobias T1 - An Exploration of Tensions in Centralized and Decentralized Digital Platform Contexts N2 - Digital platforms consist of technical elements such as software and hardware and associated social elements such as organizational processes and standards. When such social or technical elements seem logical individually but inconsistent when juxtaposed they form tensions. Prior research on platforms often focused on individual elements of digital platforms but neglected possible related and conflicting elements which offers limited insight about underlying tensions. While some studies on platforms considered tensions, they largely assumed that centralized platform owners being responsible for responding to tensions, neglecting collective response mechanisms in blockchain-based decentralized autonomous organizations (DAOs) where decentralized participants typically respond to tensions. The examination of tensions in the context of centralized platforms and decentralized autonomous organizations offers an opportunity to surface conflicting elements that form novel types of socio-technical tensions which require collective and technology-enabled response mechanisms. This thesis explored what tensions exist in centralized and decentralized digital platform contexts and how platform participants can respond to selected tensions. For this purpose, this thesis comprises five essays that employ multiple different research methods including interviews analyzed by using techniques of grounded theory, qualitative meta-analysis of published case studies, and systematic literature reviews. The findings derived from all five essays contribute to a better understanding of tensions in digital platforms. In particular, this thesis (1) offers a lens for analyzing platforms as collective organizations in which tensions arise at the collective meta-organizational level requiring collective responses, (2) identifies new tensions and response mechanisms related to generativity and collectivity, and (3) points to a novel category of socio-technical tensions that are especially salient in digital platforms. KW - Digital Platform KW - Decentralized Autonomous Organization KW - Tension KW - Grounded Theory Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-11322 ER - TY - JOUR A1 - Anagnostopoulos, Nikolaos Athanasios A1 - Teymuri, Benyamin A1 - Serati, Reza A1 - Rasti, Mehdi ED - Xie, Bin ED - Wang, Ning ED - Gu, Yi ED - Stefanidis, Angelos T1 - LP-MAB: Improving the Energy Efficiency of LoRaWAN Using a Reinforcement-Learning-Based Adaptive Configuration Algorithm JF - Sensors N2 - In the Internet of Things (IoT), Low-Power Wide-Area Networks (LPWANs) are designed to provide low energy consumption while maintaining a long communications’ range for End Devices (EDs). LoRa is a communication protocol that can cover a wide range with low energy consumption. To evaluate the efficiency of the LoRa Wide-Area Network (LoRaWAN), three criteria can be considered, namely, the Packet Delivery Rate (PDR), Energy Consumption (EC), and coverage area. A set of transmission parameters have to be configured to establish a communication link. These parameters can affect the data rate, noise resistance, receiver sensitivity, and EC. The Adaptive Data Rate (ADR) algorithm is a mechanism to configure the transmission parameters of EDs aiming to improve the PDR. Therefore, we introduce a new algorithm using the Multi-Armed Bandit (MAB) technique, to configure the EDs’ transmission parameters in a centralized manner on the Network Server (NS) side, while improving the EC, too. The performance of the proposed algorithm, the Low-Power Multi-Armed Bandit (LP-MAB), is evaluated through simulation results and is compared with other approaches in different scenarios. The simulation results indicate that the LP-MAB’s EC outperforms other algorithms while maintaining a relatively high PDR in various circumstances. KW - Internet of Things (IoT) KW - LoRaWAN KW - adaptive configuration KW - machine learning KW - reinforcement learning Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-11853 SN - 1424-8220 VL - 23 IS - 4 PB - MDPI CY - Basel, Switzerland ER - TY - JOUR A1 - Voigt, Brigitte T1 - EU regulation of gene-edited plants — A reform proposal JF - Frontiers in Genome Editing N2 - This article presents a proposal on how the European Union’s regulatory framework on genetically modified (GM) plants should be reformed in light of recent developments in genomic plant breeding techniques. The reform involves a three-tier system reflecting the genetic changes and resulting traits of GM plants. The article is intended to contribute to the ongoing debate over how best to regulate plant gene editing techniques in the EU. KW - gene editing KW - reform KW - EU regulation KW - genetically modified plant KW - new genomic techniques Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-11849 SN - 2673-3439 VL - 5 PB - Frontiers Media S.A. CY - Lausanne, Switzerland ER - TY - THES A1 - Stier, Julian T1 - Structure of Artificial Neural Networks : Empirical Investigations N2 - Within one decade, Deep Learning overtook the dominating solution methods of countless problems of artificial intelligence. "Deep" refers to the deep architectures with operations in manifolds of which there are no immediate observations. For these deep architectures some kind of structure is pre-defined -- but what is this structure? With a formal definition for structures of neural networks, neural architecture search problems and solution methods can be formulated under a common framework. Both practical and theoretical questions arise from closing the gap between applied neural architecture search and learning theory. Does structure make a difference or can it be chosen arbitrarily? This work is concerned with deep structures of artificial neural networks and examines automatic construction methods under empirical principles to shed light on to the so called ``black-box models''. Our contributions include a formulation of graph-induced neural networks that is used to pose optimisation problems for neural architecture. We analyse structural properties for different neural network objectives such as correctness, robustness or energy consumption and discuss how structure affects them. Selected automation methods for neural architecture optimisation problems are discussed and empirically analysed. With the insights gained from formalising graph-induced neural networks, analysing structural properties and comparing the applicability of neural architecture search methods qualitatively and quantitatively we advance these methods in two ways. First, new predictive models are presented for replacing computationally expensive evaluation schemes, and second, new generative models for informed sampling during neural architecture search are analysed and discussed. KW - neural architecture KW - deep learning KW - graph induced neural networks Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-14968 ER - TY - THES A1 - Hauke, Alexandra T1 - Ecofeminism and the Gothic Archives of American Folk Horror : Shadows of the Anthropos N2 - This study explores American folk horror as a mode of inquiry into the literary, cultural, filmic, ecological, and political histories of the United States. By using ecofeminist theory to read American folk horror against its roots in the frontier gothic, a genre concerned with the realities and afterlives of American settler colonialism, in turn inextricably linked with the U.S.' founding myths and national narratives that developed since the arrival of the first European settlers, my approach uncovers the dual and simultaneous exploitation of women and nature since 1492, focusing on the ways human and non-human Others continue to be at the mercy of anthropocentric and capitalocentric systems. American folk horror as genre, and the frontier gothic as its archive, allows us to see the ways American founding narratives serve as and word like folklore, contributing to the perpetuation of discrimination against underprivileged groups, especially those who are seen as nature, like women. This book offers a lengthy theorization of the genre as well as both ecofeminist readings of select texts of American folk horror (Darren Aronofsky's mother!, Shirley Jackson's We Have Always Lived in the Castle, Robert Eggers's The VVitch: A New-England Folktale) and a first discussion of a potential corpus of the genre ranging from frontier gothic literature and contemporary film to video games of the 2020s. KW - ecofeminism KW - frontier gothic KW - American folk horror KW - Anthropocene KW - settler colonialism KW - Ökofeminismus KW - Folk-Horror KW - Gothic novel KW - Amerikaforschung Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-14768 ER - TY - THES A1 - Juhos, Michael T1 - Probabilistic and geometric aspects of classical and non-commutative lp-type spaces in high dimensions N2 - This cumulative dissertation contains selected contributions to the field of asymptotic geometric analysis and high-dimensional probability. It is divided into two chapters: Chapter 1 explains some of the necessary theoretical background. In Section 1.1 it first gives a very concise history of asymptotic geometric analysis in general and then of the objects under study in particular, setting out some cornerstones in the discovery of the functional-analytic, geometric, and probabilistic properties of the spaces under consideration. The next section (1.2) gives the precise definitions and very basic properties of the three lp-type spaces that play a role in the contributed articles: the classical lp-sequence spaces, the mixed-norm sequence spaces, and the Schatten-classes Sp, each in its infinite- and finite-dimensional version. Section 1.3 is dedicated to the interplay between geometry and probability, expounding the general idea, introducing a few of the common tools, and exemplifying these on two kinds of limit theorems: Schechtman-Schmuckenschläger-type results and Poincaré-Maxwell-Borel lemmas. The first chapter concludes with Section 1.4, addressing a small sample of open questions pertaining to the contributed articles which are not answered in said articles and may be the interest of future research. The entirety of Chapter 2 consists of the contributed articles. N2 - Diese kumulative Dissertation enthält ausgewählte Beiträge zum Gebiet der asymptotischen geometrischen Analyse und der hochdimensionalen Wahrscheinlichkeit. Sie ist in zwei Kapitel geteilt: Kapitel 1 erklärt ein wenig des notwendigen theoretischen Hintergrunds. Abschnitt 1.1 bringt eine sehr kurz gefasste Geschichte der asymptotischen geometrischen Analyse im Allgemeinen und der Studienobjekte im Speziellen und legt einige Eckpunkte der Entdeckung der funktionalanalytischen, geometrischen und probabilistischen Eigenschaften der betrachteten Räume dar. Der nächste Abschnitt (1.2) gibt die genauen Definitionen und sehr grundlegenden Eigenschaften jener drei lp-artigen Räume, die in den beigetragenen Artikeln eine Rolle spielen: die klassischen lp-Folgenräume, die Folgenräume mit gemischter Norm und die Schattenklassen Sp, jeweils in der unendlich- und der endlichdimensionalen Version. Abschnitt 1.3 ist dem Zusammenspiel von Geometrie und Wahrscheinlichkeit gewidmet, er erörtert die allgemeine Idee, stellt einige der gebräuchlichen Werkzeuge vor und gibt zwei Beispiele von Grenzwertsätzen dazu: Schechtman-Schmuckenschläger-artige Ergebnisse und Poincaré-Maxwell-Borel-Lemmas. Das erste Kapitel schließt mit Abschnitt 1.4, der einen kleinen Satz von offenen Fragen anspricht, die zu den beigetragenen Artikeln gehören, darin aber nicht beantwortet werden und die das Interesse künftiger Forschung sein mögen. Kapitel 2 besteht zur Gänze aus den beigetragenen Artikeln. KW - functional analysis KW - asymptotic geometric analysis KW - limit theorems KW - lp-space KW - Schatten class Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-14857 ER - TY - THES A1 - Auer, Michael T1 - Improving Automated Android Test Generation N2 - Mobile apps are nowadays the preferred means to accomplish ubiquitous tasks like messaging, e-commerce and even playing games. Often, there exist multiple apps for the same purpose, and it is the choice of the end user to pick an appropriate app. Apps that behave unexpected, e.g., crash frequently, are sooner or later replaced, which isundesirable for the companies developing such apps. Thus, it is essential to tests apps properly before they are released onto the market. However, testing manually is often not only too cost-intensive but also too time-consuming in the short development phase, thus an automated solution is preferred. Testing mobile apps automatically received increased attention in the last decade from primarily people in academia, and several testing techniques evolved. One technique that yielded promising results, especially in different domains, is search-based software testing in which a metaheuristic, e.g., a genetic algorithm, is applied to solve an optimisation problem, e.g., test generation. A main objective of test generation is to produce tests that reveal as many faults as possible. This in turn requires the generation of tests that deeply explore the tested app. The core metric to quantify how much code tests cover is the measurement of code coverage, which can be computed at different levels of granularity ranging from determining the fraction of covered activities to a very fine-grained measurement that calculates the percentage of covered lines. This coverage information is then often used to guide the search of the employed metaheuristic. However, current automated test generation approaches produce tests with a rather low code coverage. Thus, a substantial part of tested apps remains unexplored, which in turn misses revealing deeply residing faults. We identified three core issues that are directly related to the generation of low-coverage tests. First, the applicability of current test generators is often limited. This comprises the fact that current state-of-the-art code coverage tools are incapable of instrumenting a substantial number of apps and consequently, test generators cannot utilise detailed coverage information during exploration. In addition, test generators are often only equipped with a primitive set of actions that are insufficient to simulate system events and complex user inputs. Second, the test execution is extremely time-consuming. This includes among other things the overhead associated with executing individual actions, intermediate restart operations as well as fitness evaluations. Since search-based algorithms require a substantial number of test executions to play out their strengths, the slow test execution impedes the effectiveness of the search. Third, the guidance offered by search-based algorithms is often hampered by applying inadequate fitness functions or by using non-representation-specific variation operators. In this thesis we address the problem of low-coverage tests in the Android domain by proposing several enhancements for the three identified core issues. Concerning the applicability problem, we provide the implementation of a robust code coverage tool that is capable of measuring coverage at different levels of granularity and requires no access to the source code. We also propose to include actions that can simulate system events as well as complex user inputs. Regarding the performance issue, we suggest the integration of a surrogate model that is capable of predicting the outcome of individual actions or complete tests over time in order to reduce the overall test execution costs. With respect to the lack of guidance offered by traditional search-based algorithms, we suggest alternative search strategies. In the case of a deceptive fitness landscape, we propose using novelty search algorithms. Alternatively, we suggest utilising estimation of distribution algorithms that require no crossover or mutation perators to sample new tests. While all those enhancements had a positive impact on the Android test generation process, the individual empirical studies highlighted that further research is necessary to unleash the full power of the proposed search-based algorithms. In particular, exploring complex user interfaces meaningfully requires more attention whether by introducing additional actions or by extracting valuable hints to infer reasonable text inputs. In addition, the guidance offered by fitness functions is often limited because they are either designed too coarse at all or do not accurately reflect the search objectives. Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-14955 ER - TY - RPRT A1 - Bohnenkämper, Ronja A1 - Fußeder, Christina A1 - Emmanouilidis, Georgios A1 - Emmert, Cornelia A1 - Haberger, Mathias A1 - Hartmann, Nils A1 - Hohlfeldt, Leonie A1 - Jäckel, Franziska A1 - Körber, Janina A1 - Listl, Johannes A1 - Ostendorp, Falk A1 - Pantaleon Osuna, Alvaro A1 - Steinmetzer, Luzie A1 - Thurl, Lena A1 - Ungruhe, Christian A1 - Wagener, Jonas A1 - Wehner, Stefanie ED - Ungruhe, Christian ED - Pantaleon Osuna, Alvaro ED - Wehner, Stefanie T1 - Socio-economic development and migration in rural Ghana : report from field research in Amedzofe, Volta Region N2 - Migration plays a significant role in Ghanaian society, particularly in rural areas where its impact is inextricably linked to socio-economic dynamics. In March 2023, a student field research field research project was conducted in Amedzofe as part of the international research project “Migration and Translocality in West Africa”, shedding light on various aspects of rural life through the lens of translocality. The field research aimed to address a wide range of topics related to rural livelihoods, focusing on migration and translocal aspects of everyday life. Six working groups embarked on a 10-day field research journey, employing mixed methods encompassing both quantitative and qualitative approaches. This extensive fieldwork followed a semester of intensive preparation, ensuring the thoroughness and depth of the study. The survey results were meticulously analysed and presented, providing valuable insights into the patterns, drivers and impacts of migration in the region. Additionally, the findings of the six working groups offered nuanced perspectives on various facets of rural life, including economic activities, social networks, cultural practices, education and gender aspects. This endeavour aims at fostering a deeper understanding of the complexities surrounding migration and translocality in rural Ghana. It is a testament to the dedication and vision of the late Prof. Dr. Malte Steinbrink, whose leadership and guidance were instrumental in the preparation and realisation of this study. T3 - Migration, translocality and development in times of climate change. Mitra|WA Working Paper Series - 3 KW - migration KW - translocality KW - agriculture KW - land use KW - housing KW - communication KW - education KW - gender KW - research-based learning Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-14865 IS - 3 ER - TY - JOUR A1 - Petit, Albin A1 - Cerqueus, Thomas A1 - Boutet, Antoine A1 - Ben Mokhtar, Sonia A1 - Coquil, David A1 - Brunie, Lionel A1 - Kosch, Harald T1 - SimAttack: private web search under fire JF - Journal of Internet Services and Applications N2 - Web Search engines have become an indispensable online service to retrieve content on the Internet. However, using search engines raises serious privacy issues as the latter gather large amounts of data about individuals through their search queries. Two main techniques have been proposed to privately query search engines. A first category of approaches, called unlinkability, aims at disassociating the query and the identity of its requester. A second category of approaches, called indistinguishability, aims at hiding user’s queries or user’s interests by either obfuscating user’s queries, or forging new fake queries. This paper presents a study of the level of protection offered by three popular solutions: Tor-based, TrackMeNot, and GooPIR. For this purpose, we present an efficient and scalable attack – SimAttack – leveraging a similarity metric to capture the distance between preliminary information about the users (i.e., history of query) and a new query. SimAttack de-anonymizes up to 36.7 % of queries protected by an unlinkability solution (i.e., Tor-based), and identifies up to 45.3 and 51.6 % of queries protected by indistinguishability solutions (i.e., TrackMeNot and GooPIR, respectively). In addition, SimAttack de-anonymizes 6.7 % more queries than state-of-the-art attacks and dramatically improves the performance of the attack on TrackMeNot by 23.6 %, while retaining an execution time faster by two orders of magnitude. KW - Privacy KW - Web search KW - Unlinkability KW - Indistinguishability Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-3574 SN - 1869-0238 PB - SpringerOpen ER - TY - JOUR A1 - Render, Anna A1 - Eisenbarth, Hedwig A1 - Oxner, Matt A1 - Jansen, Petra T1 - Arousal, interindividual differences and temporal binding a psychophysiological study JF - Psychological Research (ISSN: 1430-2772) N2 - The sense of agency varies as a function of arousal in negative emotional contexts. As yet, it is unknown whether the same is true for positive affect, and how inter-individual characteristics might predict these effects. Temporal binding, an implicit measure of the sense of agency, was measured in 59 participants before and after watching either an emotionally neutral film clip or a positive film clip with high or low arousal. Analyses included participants’ individual differences in subjective affective ratings, physiological arousal (pupillometry, skin conductance, heart rate), striatal dopamine levels via eye blink rates, and psychopathy. Linear mixed models showed that sexual arousal decreased temporal binding whereas calm pleasure had no facilitation effect on binding. Striatal dopamine levels were positively linked whereas subjective and physiological arousal may be negatively associated with binding towards actions. Psychopathic traits reduced the effect of high arousal on binding towards actions. These results provide evidence that individual differences influence the extent to which the temporal binding is affected by high arousing states with positive valence. KW - Sense of agency KW - Temporal binding KW - Arousal reactivity KW - Eye blink rates KW - Sexual arousal Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:101:1-2410112103084.421385257281 SN - 0340-0727 SN - 1430-2772 VL - 88 IS - 5 SP - 1653 EP - 1677 PB - Springer Berlin Heidelberg CY - Berlin/Heidelberg ER - TY - JOUR A1 - Lengler, Johannes A1 - Opris, Andre A1 - Sudholt, Dirk T1 - Analysing Equilibrium States for Population Diversity JF - Algorithmica (ISSN: 1432-0541) N2 - Population diversity is crucial in evolutionary algorithms as it helps with global exploration and facilitates the use of crossover. Despite many runtime analyses showing advantages of population diversity, we have no clear picture of how diversity evolves over time. We study how the population diversity of (μ+1)algorithms, measured by the sum of pairwise Hamming distances, evolves in a fitness-neutral environment. We give an exact formula for the drift of population diversity and show that it is driven towards an equilibrium state. Moreover, we bound the expected time for getting close to the equilibrium state. We find that these dynamics, including the location of the equilibrium, are unaffected by surprisingly many algorithmic choices. All unbiased mutation operators with the same expected number of bit flips have the same effect on the expected diversity. Many crossover operators have no effect at all, including all binary unbiased, respectful operators. We review crossover operators from the literature and identify crossovers that are neutral towards the evolution of diversity and crossovers that are not. KW - Evolutionary algorithms KW - Runtime analysis KW - Diversity KW - Population dynamics Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:101:1-2406282100292.409184699704 SN - 0178-4617 SN - 1432-0541 VL - 86 IS - 7 SP - 2317 EP - 2351 PB - Springer US CY - New York ER - TY - JOUR A1 - Nieder, Jessica A1 - van de Vijver, Ruben A1 - Ussishkin, Adam T1 - Emerging Roots: Investigating Early Access to Meaning in Maltese Auditory Word Recognition JF - Cognitive Science (ISSN: 1551-6709) N2 - In Semitic languages, the consonantal root is central to morphology, linking form and meaning. While psycholinguistic studies highlight its importance in language processing, the role of meaning in early lexical access and its representation remain unclear. This study investigates when meaning becomes accessible during the processing of Maltese verb forms, using a computational model based on the Discriminative Lexicon framework. Our model effectively comprehends and produces Maltese verbs, while also predicting response times in a masked auditory priming experiment. Results show that meaning is accessible early in lexical access and becomes more prominent after the target word is fully processed. This suggests that semantic information plays a critical role from the initial stages of lexical access, refining our understanding of real‐time language comprehension. Our findings contribute to theories of lexical access and offer valuable insights for designing priming studies in psycholinguistics. Additionally, this study demonstrates the potential of computational models in investigating the relationship between form and meaning in language processing. KW - Maltese KW - Early lexical access KW - Meaning KW - Computational modeling Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-17638 SN - 0364-0213 SN - 1551-6709 VL - 48 IS - 11 PB - Wiley ER - TY - JOUR A1 - Daschner, Stefan A1 - Obermaier, Robert T1 - Do We Use Relatively Bad (Algorithmic) Advice? The Effects of Performance Feedback and Advice Representation on Advice Usage JF - Journal of Behavioral Decision Making (ISSN: 1099-0771) N2 - Algorithms are capable of advising human decision‐makers in an increasing number of management accounting tasks such as business forecasts. Due to expected potential of these (intelligent) algorithms, there are growing research efforts to explore ways how to boost algorithmic advice usage in forecasting tasks. However, algorithmic advice can also be erroneous. Yet, the risk of using relatively bad advice is largely ignored in this research stream. Therefore, we conduct two online experiments to examine this risk of using relatively bad advice in a forecasting task. In Experiment 1, we examine the influence of performance feedback (revealing previous relative advice quality) and source of advice on advice usage in business forecasts. The results indicate that the provision of performance feedback increases subsequent advice usage but also the usage of subsequent relatively bad advice. In Experiment 2, we investigate whether advice representation, that is, displaying forecast intervals instead of a point estimate, helps to calibrate advice usage towards relative advice quality. The results suggest that advice representation might be a potential countermeasure to the usage of relatively bad advice. However, the effect of this antidote weakens when forecast intervals become less informative. KW - confidence intervals KW - forecast KW - perfect automation schema KW - performance feedback KW - relatively bad advice KW - source of advice Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-17615 SN - 0894-3257 SN - 1099-0771 VL - 37 IS - 5 PB - Wiley ER - TY - JOUR A1 - Vishnu Nampoothiri, Madhavan A1 - Entrop, Oliver A1 - Annamalai, Thillai Rajan T1 - Effect of mandatory sustainability performance disclosures on firm value: Evidence from listed European firms JF - Corporate Social Responsibility and Environmental Management (ISSN: 1535-3966) N2 - Corporate Sustainability Performance (CSP) reporting is becoming increasingly important to investors who seek to identify and invest in companies that are managing their Environmental, Social and Governance (ESG) risks effectively. The European Union's Non‐Financial Reporting Directive (NFRD), which was implemented in 2017, mandates that certain large companies must disclose their sustainability performance. This study examines the impact of the EU NFRD on the firm value of listed European firms using a difference‐in‐differences regression model. We find that the mandatory disclosure of corporate sustainability performance does not significantly affect firm value at an aggregate level. However, the results suggest minor inter‐industry differences, which can be attributed to varying sustainability performance metrics across industries. These findings contribute not only to the nascent literature on mandatory sustainability disclosures but also to the deliberations of policymakers and regulators across the world who are devising and implementing mandatory corporate sustainability performance disclosure regulations. KW - corporate social responsibility KW - ESG KW - firm value KW - mandatory disclosure KW - non‐financial reporting KW - sustainability Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-17620 SN - 1535-3958 SN - 1535-3966 VL - 31 IS - 6 SP - 5220 EP - 5235 PB - John Wiley & Sons, Inc. CY - Chichester, UK ER - TY - JOUR A1 - Schulte, Lukas A1 - Ledel, Benjamin A1 - Herbold, Steffen T1 - Studying the explanations for the automated prediction of bug and non-bug issues using LIME and SHAP JF - Empirical Software Engineering (ISSN: 1573-7616) N2 - Context The identification of bugs within issues reported to an issue tracking system is crucial for triage. Machine learning models have shown promising results for this task. However, we have only limited knowledge of how such models identify bugs. Explainable AI methods like LIME and SHAP can be used to increase this knowledge. Objective We want to understand if explainable AI provides explanations that are reasonable to us as humans and align with our assumptions about the model’s decision-making. We also want to know if the quality of predictions is correlated with the quality of explanations. Methods We conduct a study where we rate LIME and SHAP explanations based on their quality of explaining the outcome of an issue type prediction model. For this, we rate the quality of the explanations, i.e., if they align with our expectations and help us understand the underlying machine learning model. Results We found that both LIME and SHAP give reasonable explanations and that correct predictions are well explained. Further, we found that SHAP outperforms LIME due to a lower ambiguity and a higher contextuality that can be attributed to the ability of the deep SHAP variant to capture sentence fragments. Conclusion We conclude that the model finds explainable signals for both bugs and non-bugs. Also, we recommend that research dealing with the quality of explanations for classification tasks reports and investigates rater agreement, since the rating of explanations is highly subjective. KW - Explainable AI KW - LIME KW - SHAP KW - Issue type prediction Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:101:1-2409232103207.812648424894 SN - 1382-3256 SN - 1573-7616 VL - 29 IS - 4 PB - Springer US CY - New York ER - TY - JOUR A1 - Donner, Eva Katharina A1 - Meißner, Annekatrin A1 - Bort, Suleika T1 - Moving from voluntary to mandatory sustainability reporting—Transparency in sustainable development goals (SDG) reporting: An analysis of Germany's largest MNCs JF - Business Ethics, the Environment & Responsibility (ISSN: 2694-6424) N2 - A growing number of multinational companies (MNCs) report on their progress toward contributing to the Sustainable Development Goals (SDGs) in their annual reports, yet the amount and quality of the information they disclose varies significantly. The aim of this study is twofold: First, we investigate how transparent MNCs report on their SDG engagement and second, we study how the reported SDG engagement changed over time due to major shifts in sustainability reporting requirements. Using a dataset of the largest German MNCs, we analyze their disclosure of SDG contribution reporting practices. Our results show that, overall, between 2016 and 2021 all German MNCs increased their SDG reporting activity and that the MNCs adopted four different practices to report their SDG engagement. We also found that the largest MNCs were more transparent and systematic in their SDG reporting than smaller MNCs, whose reporting was more heterogeneous. Our study contributes to legitimacy research and the role of transparency in corporate reporting as well as the debates on the efficacy of sustainability reporting legislation in the context of SDG engagement. Our findings imply that regulations on environmental and social regulation increase the transparency of sustainability reporting. KW - multinational companies (MNCs) KW - sustainability reporting KW - transparency KW - UN sustainable development goals Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-16527 SN - 2694-6416 SN - 2694-6424 VL - 34 IS - 3 SP - 900 EP - 911 PB - Wiley ER - TY - JOUR A1 - Aistleitner, Christoph A1 - Frühwirth, Lorenz A1 - Prochno, Joscha T1 - Diophantine conditions in the law of the iterated logarithm for lacunary systems JF - Probability Theory and Related Fields (ISSN: 1432-2064) N2 - It is a classical observation that lacunary function systems exhibit many properties which are typical for systems of independent random variables. However, it had already been observed by Erdős and Fortet in the 1950s that probability theory’s limit theorems may fail for lacunary sums (sum f(n_k x)) if the sequence ((n_k)_{k ge 1}) has a strong arithmetic “structure”. The presence of such structure can be assessed in terms of the number of solutions k, l of two-term linear Diophantine equations (an_k - bn_l = c). As the first author proved with Berkes in 2010, saving an (arbitrarily small) unbounded factor for the number of solutions of such equations compared to the trivial upper bound, rules out pathological situations as in the Erdős–Fortet example, and guarantees that (sum f(n_k x)) satisfies the central limit theorem (CLT) in a form which is in accordance with true independence. In contrast, as shown by the first author, for the law of the iterated logarithm (LIL) the Diophantine condition which suffices to ensure “truly independent” behavior requires saving this factor of logarithmic order. In the present paper we show that, rather surprisingly, saving such a logarithmic factor is actually the optimal condition in the LIL case. This result reveals the remarkable fact that the arithmetic condition required of ((n_k)_{k ge 1}) to ensure that (sum f(n_k x)) shows “truly random” behavior is a different one at the level of the CLT than it is at the level of the LIL: the LIL requires a stronger arithmetic condition than the CLT does. KW - Lacunary trigonometric sums KW - Law of the iterated logarithm KW - Diophantine equations Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:101:1-2406190937284.886045166092 SN - 0178-8051 SN - 1432-2064 VL - 192 IS - 1 SP - 545 EP - 574 PB - Springer CY - Berlin/Heidelberg ER - TY - JOUR A1 - Beurskens, Michael A1 - Scherzinger, Stefanie T1 - Legal Perspectives on Research Data Storage JF - Datenbank-Spektrum (ISSN: 1618-2162) N2 - Responsibly managing research data has become increasingly important for researchers, especially within the database research community. Despite significant progress in best practices, the state-of-the-art in research data storage is lacking from a legal perspective. We introduce the stakeholders and the dynamic nature of their relationships (such as researchers changing affiliation) and observe that no existing infrastructure for research data storage fully meets their requirements. Therefore, we emphasize the need to design a comprehensive system architecture for research data storage that is aligned with legal considerations from the start, rather than as an afterthought. KW - Storage Contract KW - Copyright KW - Sui Generis Right KW - Privacy KW - Trade Secrets KW - Research Data Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:101:1-2410012125227.647518861484 SN - 1618-2162 SN - 1610-1995 VL - 24 IS - 2 SP - 85 EP - 95 PB - Springer CY - Berlin/Heidelberg ER - TY - JOUR A1 - Franke, Jan A1 - Heinrich, Florian A1 - Reisch, Raven T. T1 - Vision based process monitoring in wire arc additive manufacturing (WAAM) JF - Journal of Intelligent Manufacturing (ISSN: 1572-8145) N2 - A stable welding process is crucial to obtain high quality parts in wire arc additive manufacturing. The complexity of the process makes it inherently unstable, which can cause various defects, resulting in poor geometric accuracy and material properties. This demands for in-process monitoring and control mechanisms to industrialize the technology. In this work, process monitoring algorithms based on welding camera image analysis are presented. A neural network for semantic segmentation of the welding wire is used to monitor the working distance as well as the horizontal position of the wire during welding and classic image processing techniques are applied to capture spatter formation. Using these algorithms, the process stability is evaluated in real time and the analysis results enable the direction independent closed-loop-control of the manufacturing process. This significantly improves geometric fidelity as well as mechanical properties of the fabricated part and allows the automated production of parts with complex deposition paths including weld bead crossings, curvatures and overhang structures. KW - Wire arc additive manufacturing KW - Vision based monitoring KW - Machine learning KW - Nozzle-to-work distance monitoring KW - Contact tube wear off detection KW - Spatter detection Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:101:1-2405052141549.085870766506 SN - 0956-5515 SN - 1572-8145 VL - 36 IS - 3 SP - 1711 EP - 1721 PB - Springer US CY - New York ER - TY - BOOK ED - Hennemann, Moritz ED - Lewinski, Kai von ED - Wawra, Daniela ED - Widjaja, Thomas T1 - Data disclosure BT - global developments and perspectives T3 - Global and comparative data law (edited by Moritz Hennemann; Lea Katharina Kumkar; Linda Kuschel; Björn Steinrötter) KW - Personenbezogene Daten KW - Datenübermittlung KW - Datenschutz KW - Rechtsvergleich Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:101:1-2023031216403784842331 VL - 2023 IS - volume 2 PB - Walter de Gruyter CY - Berlin/Boston ER - TY - JOUR A1 - Rieger, Eva T1 - A Manchurian Candidate? The GOP’s Discourse on the Russian War in Ukraine T1 - Ein Manchurian-Kandidat? Der Diskurs der Republikanischen Partei zu Russlands Krieg in der Ukraine JF - Politische Vierteljahresschrift (ISSN: 1862-2860) N2 - The United States has a longstanding tradition regarding its overall foreign policy, in the form of a bipartisan consensus. This includes—among other things—maintaining alliances and curbing the influence of rivals (e.g., Russia). Since this consensus has been in place, traditionally the Republican Party (GOP) has been especially intent on a less cooperative and more containing or deterring stance towards Russia. With former U.S. President Donald Trump, we can see a turning point in this behaviour by the GOP. Trump’s obvious admiration for Russian president Putin and his statements about Putin being overly favourable, while simultaneously questioning NATO and the United States’ commitment to defend Eastern European partners, show a distinctive shift in the GOP’s discourse. This renunciation has subsequently been picked up by parts of the Republican Party, rendering the bipartisan consensus a contested issue. The full-scale Russian invasion of Ukraine in February 2022 now constitutes an important external shock influencing said discursive shift. By drawing on discourse-bound identity theory and discourse analysis, the GOP’s discourse regarding Russia and NATO is expected to have (substantially) changed in a kind of Zeitenwende —back towards the bipartisan consensus. This article will, therefore, analyse the statements of prominent Republicans after the Russian invasion, compare them to Trump’s positions on these issues, and identify whether the invasion serves as a formative event that creates an overall shift in rhetoric and positions. N2 - Die USA haben eine langanhaltende Tradition in ihrer allgemeinen Außenpolitik, in Form des sog. „bipartisan consensus“. Darin enthalten sind u. a. das Erhalten von Allianzen und die Einschränkung des Einflusses von Rivalen (bspw. Russlands). Seit dieser Konsens existiert, verfolgen die Republikaner traditionellerweise einen weniger kooperativen, eher einhegenden und abschreckenden Kurs gegenüber Russland. Mit dem früheren US-Präsidenten Trump kann man hier eine Wende im Verhalten der Partei erkennen. Die Verschiebung des Republikanischen Diskurses zeigt sich klar mit seiner offensichtlichen Bewunderung für Russlands Präsident Putin und seinen lobenden Aussagen über diesen, während er die NATO und die Verteidigungspflicht gegenüber osteuropäischen Partnern hinterfragt. Diese Abkehr von früheren Positionen wurde daraufhin von Teilen der Republikanischen Partei übernommen, wodurch der bisherige „bipartisan consensus“ contestet wird. Die russische Invasion der Ukraine im Februar 2022 stellt hierbei nun einen entscheidenden externen Schock dar, der diesen diskursiven Wandel beeinflussen kann. Unter der Einbeziehung der diskursgebundenen Identitätstheorie und einer Diskursanalyse wird davon ausgegangen, dass sich der Republikanische Diskurs zu Russland und der NATO (erheblich) gewandelt hat – zurück zum „bipartisan consensus“ in einer Art Zeitenwende . Dafür werden in diesem Artikel Aussagen relevanter Republikaner:innen nach der russischen Invasion analysiert, mit den Positionen Trumps zu diesen Themen verglichen und festgestellt, ob es sich demnach um ein formatives Ereignis handelt, durch das ein genereller Wandel in Rhetorik und Einstellungen entsteht. KW - - KW - U.S. foreign policy discourse KW - Republican Party KW - NATO KW - Ukraine war KW - Bipartisan consensus KW - US-Außenpolitik Diskurs KW - Republikanische Partei KW - NATO KW - Ukraine-Krieg KW - Bipartisan consensus Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:101:1-2411132119230.713822872360 SN - 0032-3470 SN - 1862-2860 VL - 66 IS - 1 SP - 77 EP - 99 PB - Springer Fachmedien CY - Wiesbaden ER - TY - JOUR A1 - Andraschko, Bernhard A1 - Danner, Julian A1 - Kreuzer, Martin T1 - SAT Solving Using XOR-OR-AND Normal Forms JF - Mathematics in Computer Science (ISSN: 1661-8289) N2 - This paper introduces the XOR-OR-AND normal form (XNF) for logical formulas. It is a generalization of the well-known Conjunctive Normal Form (CNF) where literals are replaced by XORs of literals. As a first theoretic result, we show that every CNF formula is equisatisfiable to a formula in 2-XNF, i.e., a formula in XNF where each clause involves at most two XORs of literals. Subsequently, we present an algorithm which converts Boolean polynomials efficiently from their Algebraic Normal Form (ANF) to formulas in 2-XNF. Experiments with the cipher ASCON-128 show that cryptographic problems, which by design are based strongly on XOR-operations, can be represented using far fewer variables and clauses in 2-XNF than in CNF. In order to take advantage of this compact representation, new SAT solvers based on input formulas in 2-XNF need to be designed. By taking inspiration from graph-based 2-CNF SAT solving, we devise a new DPLL-based SAT solver for formulas in 2-XNF. Among others, we present advanced pre- and in-processing techniques. Finally, we give timings for random 2-XNF instances and instances related to key recovery attacks on round reduced ASCON-128, where our solver outperforms state-of-the-art alternative solving approaches. KW - - KW - SAT solving KW - XOR constraint KW - Algebraic normal form KW - Implication graph KW - Cryptographic attack KW - 03B70 KW - 13P15 KW - 05C90 KW - 94A60 Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:101:1-2502242130589.859216082138 SN - 1661-8270 SN - 1661-8289 VL - 18 IS - 4 PB - Springer International Publishing CY - Cham ER - TY - JOUR A1 - Goerigk, Marc A1 - Khosravi, Mohammad T1 - Robust combinatorial optimization problems under budgeted interdiction uncertainty JF - OR Spectrum (ISSN: 1436-6304) N2 - In robust combinatorial optimization, we would like to find a solution that performs well under all realizations of an uncertainty set of possible parameter values. How we model this uncertainty set has a decisive influence on the complexity of the corresponding robust problem. For this reason, budgeted uncertainty sets are often studied, as they enable us to decompose the robust problem into easier subproblems. We propose a variant of discrete budgeted uncertainty for cardinality-based constraints or objectives, where a weight vector is applied to the budget constraint. We show that while the adversarial problem can be solved in linear time, the robust problem becomes NP-hard and not approximable. We discuss different possibilities to model the robust problem and show experimentally that despite the hardness result, some models scale relatively well in the problem size. KW - - KW - Robust optimization KW - Combinatorial optimization KW - Budgeted uncertainty KW - Knapsack uncertainty Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:101:1-2408131120370.349068848723 SN - 0171-6468 SN - 1436-6304 VL - 47 IS - 1 SP - 255 EP - 285 PB - Springer CY - Berlin/Heidelberg ER - TY - JOUR A1 - Kosch, Harald A1 - Brunie, Lionel A1 - Mayer, Tobias A1 - Hasan, Omar A1 - Schiedermeier, Maximilian T1 - Anonymous voting using distributed ledger-assisted secure multi-party computation JF - Applied Network Science N2 - High voter turnout in elections and referendums is desirable to ensure a robust democracy. Secure electronic voting is a vision for the future of elections and referendums. Such a system can counteract factors hindering strong voter turnout such as the requirement of physical presence during limited hours at polling stations. However, this vision brings transparency and confidentiality requirements that render the design of such solutions challenging. Specifically, the counting implementation must support reproducibility, and the choice of individual voters must remain confidential. In this paper, we propose and evaluate a novel referendum protocol that ensures transparency, confidentiality, and integrity, in trustless networks. The protocol is built by combining secure multi-party computation and distributed ledger technology, e.g., a Blockchain. The persistence and immutability of the protocol communication allow verifiability of the referendum outcome by any participant. Voters therefore do not need to trust third parties. We provide a formal description and conduct a thorough security evaluation of our proposal. KW - E-voting KW - Distributed ledger KW - Trustless networks KW - Transparency Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus4-15176 VL - 2024 IS - 9 PB - Springer International Publishing CY - Cham (Schweiz) ER -