TY - GEN ED - Herrmann, Frank T1 - Proceedings of the 14th International Conference on Advances in System Simulation, SIMUL 2022, October 16 - 20, 2022, Lisbon, Portugal Y1 - 2022 UR - https://www.thinkmind.org/download_full.php?instance=SIMUL+2022 SN - 978-1-68558-001-8 SN - 2308-4537 PB - IARIA XPS Press ER - TY - CHAP A1 - Weber, Karsten ED - George, Wolfgang Michael ED - Weber, Karsten T1 - Künstliche Intelligenz und Sterben just in time T2 - Wie werden wir in Zukunft sterben? - Szenarien zu Sterben Tod und Trauer im Jahr 2045 Y1 - 2023 SN - 9783837961058 U6 - https://doi.org/10.30820/9783837961058-249 SP - 249 EP - 268 PB - Psychosozial-Verlag CY - Gießen ER - TY - CHAP A1 - Weber, Karsten ED - George, Wolfgang Michael ED - Weber, Karsten T1 - Mensch und Technik, Mensch durch Technik T2 - Wie werden wir in Zukunft sterben? - Szenarien zu Sterben Tod und Trauer im Jahr 2045 Y1 - 2023 SN - 9783837961058 U6 - https://doi.org/10.30820/9783837961058-49 SP - 49 EP - 60 PB - Psychosozial-Verlag CY - Gießen ER - TY - CHAP A1 - Fuxen, Philipp A1 - Hackenberg, Rudolf A1 - Heinl, M. P. A1 - Schunck, C. H. A1 - Yahalom, R. T1 - MANTRA: A Graph-based Unified Information Aggregation Foundation for Enhancing Cybersecurity Management in Critical Infrastructures // Aufsatznr.: P-335 T2 - Lecture Notes in Informatics (LNI), Proceedings - Series of the Gesellschaft fur Informatik (GI), N2 - The digitization of almost all sectors of life and the quickly growing complexity of interrelationships between actors in this digital world leads to a dramatically increasing attack surface regarding both direct and also indirect attacks over the supply chain. These supply chain attacks can have different characters, e.g., vulnerabilities and backdoors in hardware and software, illegitimate access by compromised service providers, or trust relationships to suppliers and customers exploited in the course of business email compromise. To address this challenge and create visibility along these supply chains, threat-related data needs to be rapidly exchanged and correlated over organizational borders. The publicly funded project MANTRA is meant to create a secure and resilient framework for real-time exchange of cyberattack patterns and automated, contextualized risk management. The novel graph-based approach provides benefits for automation regarding cybersecurity management, especially when it comes to prioriization of measures for risk reduction and during active defense against cyberattacks. In this paper, we outline MANTRA’s scope, objectives, envisioned scientific approach, and challenges. Y1 - 2023 U6 - https://doi.org/10.18420/OID2023_10 SP - 123 EP - 128 ER - TY - GEN A1 - Fischer, Sebastian T1 - A Security-, Privacy-and Usability-Scoring System for IoT Devices Y1 - 2022 UR - https://www.researchgate.net/publication/364284332_A_Security-_Privacy-and_Usability-Scoring_System_for_IoT_Devices UR - 978-1-61208-948-5 ER - TY - CHAP A1 - Hachani, Murad A1 - Stey, Miguel A1 - Fuxen, Philipp A1 - Graf, Julian A1 - Hackenberg, Rudolf T1 - GFDG: a genetic fuzzing method for the Controller Area Network Protocol T2 - Cloud Computing 2025 : The Sixteenth International Conference on Cloud Coud Computing, GRIDs, and Virtualization, 06.-10. April 2025, Valencia N2 - Ensuring the security of modern automotive systems is critical due to their increasing complexity and reliance on interconnected Electronic Control Units. The Controller Area Network still serves as a key communication protocol within these systems, making it a primary target for security testing. Traditional fuzz testing approaches for Controller Area Networks often rely on random or brute-force message generation, not leveraging the system’s feedback to improve the generation process. This paper introduces the Genetic Fuzz Data Generator, a fuzzing method that leverages Genetic Algorithms and side-channel analysis to enhance Controller Area Network security testing. The Genetic Fuzz Data Generator dynamically refines its fuzzing strategy by evaluating system responses through side-channel data, such as processing unit temperatures and power supply variations. By structuring Controller Area Network messages as genetic individuals and applying evolutionary principles—including selection, crossover, and mutation—the Genetic Fuzz Data Generator systematically identifies active Controller Area Network IDs and generates targeted fuzz messages. Experimental validation was conducted on a real automotive electronic control unit within a controlled laboratory setup. The first results demonstrated the approach’s effectiveness, revealing system anomalies, including a Denial of Service vulnerability that disrupted functions of the investigated Electronic Control Unit. The findings highlight the potential of feedback-driven fuzzing for improving the efficiency of black-box security testing in Controller Area Network-based systems. Future research could further optimize fitness functions or explore additional side-channel metrics. Y1 - 2025 UR - https://www.thinkmind.org/library/CLOUD_COMPUTING/CLOUD_COMPUTING_2025/cloud_computing_2025_1_60_28009.html SN - 978-1-68558-258-6 SN - 2308-4294 SP - 40 EP - 45 ER - TY - CHAP A1 - Buchmann, Thomas A1 - Schwägerl, Felix A1 - Peinl, René T1 - To Model, to Prompt, or to Code? The Choice Is Yours: A Multi-Paradigmatic Approach to Software Development T2 - Proceedings of the 20th International Conference on Software Technologies, 10-12.Juni 2025, Bilbao N2 - This paper considers three fundamental approaches to software development, namely manual coding, model-driven software engineering, and code generation by large language models. All of these approaches have their individual pros and cons, motivating the desire for an integrated approach. We present MoProCo, a technical solution to integrate the three approaches into a single tool chain, allowing the developer to split a software engineering task into modeling, prompting or coding sub-tasks. From a single input file consisting of static model structure, natural language prompts and/or source code fragments, Java source code is generated using a two-stage approach. A case study demonstrates that the MoProCo approach combines the desirable properties of the three development approaches by offering the appropriate level of abstraction, determinism, and dynamism for each specific software engineering sub-task. Y1 - 2025 U6 - https://doi.org/10.5220/0013557100003964 SP - 296 EP - 303 PB - SCITEPRESS - Science and Technology Publications ER - TY - CHAP A1 - Reichel, Tobias A1 - Gerstner, Mathias A1 - Schiller, Leo A1 - Attenberger, Andreas A1 - Hackenberg, Rudolf A1 - Dološ, Klara T1 - A forensic analysis of GNSS spoofing attacks on autonomous vehicles T2 - Cloud Computing 2025 : The Sixteenth International Conference on Cloud Computing, GRIDs, and Virtualization, 06.-10. April 2025, Valencia N2 - Global Navigation Satellite Systems (GNSSs) are essential for modern technology, enabling precise geographic positioning in aviation, maritime shipping, and automotive systems. In the future, their role will be even more critical for autonomous vehicles, which rely on accurate localization for navigation and decision-making. However, the increasing connectivity of autonomous vehicles exposes them to cyber threats, including GNSS spoofing attacks, which manipulate location data to mislead onboard systems. As reliance on GNSS grows, so does the risk posed by spoofing attacks, making it a critical security concern. This paper describes GNSS spoofing attacks on autonomous vehicles, focusing on their detection both during and after an attack. Furthermore, we analyze data storage strategies to facilitate effective forensic analysis. We highlight the importance of position, signal, and camera data, which should be preserved to ensure a comprehensive forensic investigation. Finally, we suggest a simulation setup that enables studying which data could be used for a forensic investigation. Additionally, we examine established data frameworks and decide whether they are suitable for detecting GNSS spoofing attacks. Y1 - 2025 UR - https://www.thinkmind.org/articles/cloud_computing_2025_1_50_28008.pdf SN - 978-1-68558-258-6 SN - 2308-4294 SP - 32 EP - 39 ER - TY - THES A1 - Altweck, Ricardo T1 - Analysing Learning Behaviour in Moodle: A Heuristic and AI-Driven Approach BT - A Thesis N2 - In this thesis, a novel evaluation method to determine the duration of learning sessions and the completion of learning material is introduced. Screen recordings of students’ browser sessions are utilised to capture detailed, low-level learner activity in a blended learning environment.The accumulated recordings are analysed to define a continuous completion state for individual learning material, focusing on the exact time a student spends on the material and their activity during this period. The evaluation method is adapted to the type of material, such as PDF documents, quizzes, or video lectures. The results demonstrate the potential of this approach, based on analysis of two distinct time frames: an exam preparation period and a lecture period. Additionally, an AI-driven approach is outlined to further refine the chosen definition of learning material completion. KW - Learning Analytics KW - Student Engagement KW - Session Replays KW - LMS KW - Blended Learning Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-79210 CY - Regensburg ER - TY - JOUR A1 - Kopper, Andreas A1 - Fürstenau, Daniel A1 - Zimmermann, Stephan A1 - Klotz, Stefan A1 - Rentrop, Christopher A1 - Rothe, Hannes A1 - Strahringer, Susanne A1 - Westner, Markus T1 - Shadow IT and Business-Managed IT: A Conceptual Framework and Empirical Illustration JF - International Journal of IT/Business Alignment and Governance (IJITBAG) N2 - Research on Shadow IT is facing a conceptual dilemma in cases where previously “covert” systems developed by business entities are integrated in the organizational IT management. These systems become visible, are thus not “in the shadows” anymore, and subsequently do not fit to existing definitions of Shadow IT. Practice shows that some information systems share characteristics of Shadow IT but are created openly in alignment with the IT organization. This paper proposes the term “Business-managed IT” to describe “overt” information systems developed or managed by business entities and distinguishes it from Shadow IT by illustrating case vignettes. Accordingly,our contribution is to suggest a concept and its delineation against other concepts. In this way, IS researchers interested in IT originated from or maintained by business entities can construct theories with a wider scope of application that are at the same time more specific to practical problems. In addition, the terminology allows to value potentially innovative developments by business entities more adequately. KW - Alignment KW - Business-managed IT KW - IT governance KW - Shadow IT KW - Unternehmen KW - Informationstechnik KW - Datensicherung KW - Organizational IT management Y1 - 2018 U6 - https://doi.org/10.4018/IJITBAG.2018070104 VL - 9 IS - 2 SP - 53 EP - 71 PB - IGI Global ER - TY - JOUR A1 - Käss, Sebastian A1 - Strahringer, Susanne A1 - Westner, Markus T1 - A Multiple Mini Case Study on the Adoption of Low Code Development Platforms in Work Systems JF - IEEE Access N2 - Although adopting Low Code Development Platforms (LCDPs) promises significant efficiency and effectiveness improvements for application development, its adoption still needs further empirical research. This paper uses a combinatorial approach to research LCDP adoption and presents the results of a multiple mini case study with 36 cases on LCDP adoption. A combination of the Socio-Technical Systems theory and the Technology-Organisational-Environment model is used as a theoretical lens. In this paper, we show that LCDP adoption is a multifaceted phenomenon and identify three archetypes for LCDP adoption (i.e., IT Resource Shortage Mitigators, Application Development Democratisers, and Synergy Realisers) and one archetype for LCDP non-adoption (i.e., Intricacy Adversaries). Each archetype can be interpreted as an individual path towards LCDP (non-)adoption. Based on these archetypes, we derive seven starting points for practitioners to adopt LCDPs in work systems. Moreover, by using the theoretical lenses, the paper shows that for an LCDP adoption to occur, an optimisation of the social and technical sub-systems is required. KW - Low Code Development Platform KW - Adoption KW - Case study Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-65634 SN - 2169-3536 N1 - Corresponding author: Markus Westner SP - 118762 EP - 118786 PB - IEEE ER - TY - JOUR A1 - Borg, Leise A1 - Frikel, Jürgen A1 - Jørgensen, Jakob Sauer A1 - Quinto, Eric Todd T1 - Analyzing Reconstruction Artifacts from Arbitrary Incomplete X-ray CT Data JF - SIAM Journal on Imaging Sciences N2 - This article provides a mathematical analysis of singular (nonsmooth) artifacts added to reconstructions by filtered backprojection (FBP) type algorithms for X-ray computed tomography (CT) with arbitrary incomplete data. We prove that these singular artifacts arise from points at the boundary of the data set. Our results show that, depending on the geometry of this boundary, two types of artifacts can arise: object-dependent and object-independent artifacts. Object-dependent artifacts are generated by singularities of the object being scanned, and these artifacts can extend along lines. They generalize the streak artifacts observed in limited-angle tomography. Object-independent artifacts, on the other hand, are essentially independent of the object and take one of two forms: streaks on lines if the boundary of the data set is not smooth at a point and curved artifacts if the boundary is smooth locally. We prove that these streak and curve artifacts are the only singular artifacts that can occur for FBP in the continuous case. In addition to the geometric description of artifacts, the article provides characterizations of their strength in Sobolev scale in certain cases. The results of this article apply to the well-known incomplete data problems, including limited-angle and regionof-interest tomography, as well as to unconventional X-ray CT imaging setups that arise in new practical applications. Reconstructions from simulated and real data are analyzed to illustrate our theorems, including the reconstruction that motivated this work a synchrotron data set in which artifacts appear on lines that have no relation to the object. KW - DATA TOMOGRAPHY KW - Fourier integral operators KW - GENERALIZED RADON-TRANSFORM KW - IMAGE-RECONSTRUCTION KW - incomplete data tomography KW - limited-angle tomography KW - METAL ARTIFACTS KW - microlocal analysis KW - PROJECTIONS KW - reconstruction artifact KW - region-of-interest tomography KW - SINGULARITIES KW - wavefront set KW - X-ray tomography Y1 - 2018 U6 - https://doi.org/10.1137/18M1166833 VL - 11 IS - 4 SP - 2786 EP - 2814 PB - SIAM PUBLICATIONS ER - TY - JOUR A1 - Kopper, Andreas A1 - Klotz, Stefan A1 - Westner, Markus A1 - Strahringer, Susanne T1 - Shadow IT and Business-managed IT BT - Practitioner Perceptions and Their Comparison to Literature JF - Journal of Information Technology Management (JITM) N2 - Two concepts describe the autonomous deployment of IT by business entities: Shadow IT and Business-managed IT. Shadow IT is deployed covertly, that is, software, hardware, or IT services created/procured or managed by business entities without alignment with the IT organization. In contrast, Business-managed IT describes the overt deployment of IT, that is, in alignment with the IT organization or in a split responsibility model. The purpose of this paper is to extend the conceptual understanding of Shadow IT and Business-managed IT, comparing the perceptions of 29 CIOs and senior IT managers with the results of a systematic literature review. By doing so, this paper presents a structured and comprehensive view of causing factors, outcomes, and governance of Shadow IT and Business-managed IT in practice. A comparison of academic literature and practitioner perceptions reveals the limitations and gaps of the current research and highlights avenues for future research. The authors find three category-spanning themes occurring as causing factors, outcomes, and—as part of governance measures—factors to improve the IT organization: (1) (Poor) business-IT alignment (2) (lack of) agility, and (3) (lack of) policies. This study is innovative with its comprehensive qualitative interview data that the authors compare to the existing literature. Therefore, the paper brings together theoretical and practical insights into Shadow IT and Businessmanaged IT, which should aid practitioners and scholars in decision making and future research. KW - Corporate Governance KW - Strategisches Management KW - Shadow IT KW - Business-managed IT KW - IT governance KW - Agility KW - Business-IT alignment KW - Informationsmanagement Y1 - 2019 UR - http://home.thejitm.org/XXX-4/contents.html SN - 1042-1319 VL - 30 IS - 4 ER - TY - JOUR A1 - Käss, Sebastian A1 - Brosig, Christoph A1 - Westner, Markus A1 - Strahringer, Susanne T1 - Short and sweet: multiple mini case studies as a form of rigorous case study research JF - Information Systems and e-Business Management N2 - Case study research is one of the most widely used research methods in Information Systems (IS). In recent years, an increasing number of publications have used case studies with few sources of evidence, such as single interviews per case. While there is much methodological guidance on rigorously conducting multiple case studies, it remains unclear how researchers can achieve an acceptable level of rigour for this emerging type of multiple case study with few sources of evidence, i.e., multiple mini case studies. In this context, we synthesise methodological guidance for multiple case study research from a cross-disciplinary perspective to develop an analytical framework. Furthermore, we calibrate this analytical framework to multiple mini case studies by reviewing previous IS publications that use multiple mini case studies to provide guidelines to conduct multiple mini case studies rigorously. We also offer a conceptual definition of multiple mini case studies, distinguish them from other research approaches, and position multiple mini case studies as a pragmatic and rigorous approach to research emerging and innovative phenomena in IS. KW - Case study research KW - Multiple mini case study KW - Short case study KW - Methodological guidance Y1 - 2024 U6 - https://doi.org/10.1007/s10257-024-00674-2 PB - Springer Nature ER - TY - JOUR A1 - Klotz, Stefan A1 - Kopper, Andreas A1 - Westner, Markus A1 - Strahringer, Susanne T1 - Von Schatten-IT zu Business-managed IT: Fachbereichs-IT gezielt gestalten JF - Wirtschaftsinformatik & Management N2 - Fachbereichs-IT, Schatten-IT, Business-managed IT. All diese Begriffe beschreiben IT, die neben den eigentlichen, regulären IT-Systemen oder -Prozessen in Unternehmen existieren und von Mitarbeiterinnen und Mitarbeitern der Fachbereiche genutzt werden. Im Fall von„Schatten-IT“ handelt es sich um IT-Systeme und -Prozesse (IT-Instanzen), die sich ohne Kenntnis der IT-Verantwortlichen etabliert haben; im Fall von„Business-managed IT“ entstehen die IT-Systeme und -Prozesse in Kenntnis der bzw. in Abstimmung mit den IT-Verantwortlichen im Unternehmen.„Fachbereichs-IT“ subsumiert Schatten-IT und Business-managed IT. Welche Ursachen führen zu solchen IT-Instanzen, welche Potenziale und Risiken haben diese IT-Instanzen und wie lassen sie sich steuern? KW - Business-managed IT KW - Fachbereichs IT KW - IT Governance KW - Schatten IT KW - Shadow IT Y1 - 2022 U6 - https://doi.org/10.1365/s35764-022-00421-7 SN - 1867-5913 SN - 1867-5905 VL - 14 IS - 4 SP - 282 EP - 287 PB - Springer Nature ER - TY - CHAP A1 - Joblin, Mitchell A1 - Apel, Sven A1 - Hunsen, Claus A1 - Mauerer, Wolfgang T1 - Classifying Developers into Core and Peripheral: An Empirical Study on Count and Network Metrics T2 - 2017 IEEE/ACM 39th International Conference on Software Engineering (ICSE), Buenos Aires, Argentina, 20-28 May 2017 N2 - Knowledge about the roles developers play in a software project is crucial to understanding the project's collaborative dynamics. In practice, developers are often classified according to the dichotomy of core and peripheral roles. Typically, count-based operationalizations, which rely on simple counts of individual developer activities (e.g., number of commits), are used for this purpose, but there is concern regarding their validity and ability to elicit meaningful insights. To shed light on this issue, we investigate whether count-based operationalizations of developer roles produce consistent results, and we validate them with respect to developers' perceptions by surveying 166 developers. Improving over the state of the art, we propose a relational perspective on developer roles, using fine-grained developer networks modeling the organizational structure, and by examining developer roles in terms of developers' positions and stability within the developer network. In a study of 10 substantial open-source projects, we found that the primary difference between the count-based and our proposed network-based core-peripheral operationalizations is that the network-based ones agree more with developer perception than count-based ones. Furthermore, we demonstrate that a relational perspective can reveal further meaningful insights, such as that core developers exhibit high positional stability, upper positions in the hierarchy, and high levels of coordination with other core developers, which confirms assumptions of previous work. Y1 - 2017 U6 - https://doi.org/10.1109/icse.2017.23 SP - 164 EP - 174 PB - IEEE ER - TY - CHAP A1 - Klotz, Stefan A1 - Westner, Markus A1 - Strahringer, Susanne T1 - From Shadow IT to Business-managed IT and Back Again BT - How Responsibility for IT Instances Evolves Over Time T2 - Pacific Asia Conference on Information Systems (PACIS): 2020, Dubai N2 - Today, information technology (IT) is not anymore solely deployed and maintained by the IT organization, but also by business units. IT deployed or managed by business units is called Shadow IT (without alignment with the IT organization) or Business-managed IT (in alignment or a split responsibility model with the IT organization), contrasting “classical” IT. However, the responsibility for deployed IT might change over time. Therefore, this paper conceptualizes the progression of the responsibility for IT as a trajectory through initialization, potential transitions, and discontinuance. The paper illustrates this conceptual framework using four exemplary case vignettes of IT instances. Empirical findings of the case vignettes determine indications when employees initialize an IT instance as Shadow IT, Business-managed IT, or IT-managed systems and reasons why the responsibility for an IT instance changes over time. The results suggest that scholars and practitioners should add a temporal dimension to the governance of IT instances. KW - IT-Governance KW - Shadow IT KW - Business-managed IT KW - Shadow IT KW - Business-managed IT KW - IT governance KW - trajectory KW - application governance Y1 - 2020 UR - https://aisel.aisnet.org/pacis2020/94/ ER - TY - JOUR A1 - Klotz, Stefan A1 - Kopper, Andreas A1 - Westner, Markus A1 - Strahringer, Susanne T1 - Causing factors, outcomes, and governance of Shadow IT and business-managed IT BT - A systematic literature review JF - International Journal of Information Systems and Project Management N2 - Shadow IT and Business-managed IT describe the autonomous deployment/procurement or management of Information Technology (IT) instances, i.e., software, hardware, or IT services, by business entities. For Shadow IT, this happens covertly, i.e., without alignment with the IT organization; for Business-managed IT this happens overtly, i.e., in alignment with the IT organization or in a split responsibility model. We conduct a systematic literature review and structure the identified research themes in a framework of causing factors, outcomes, and governance. As causing factors, we identify enablers, motivators, and missing barriers. Outcomes can be benefits as well as risks/shortcomings of Shadow IT and Business-managed IT. Concerning governance, we distinguish two subcategories: general governance for Shadow IT and Business-managed IT and instance governance for overt Business-managed IT. Thus, a specific set of governance approaches exists for Business-managed IT that cannot be applied to Shadow IT due to its covert nature. Hence, we extend the existing conceptual understanding and allocate research themes to Shadow IT, Business-managed IT, or both concepts and particularly distinguish the governance of the two concepts. Besides, we find that governance themes have been the primary research focus since 2016, whereas older publications (until 2015) focused on causing factors. KW - Shadow IT KW - Business-managed IT KW - IT governance KW - literature review KW - outcomes KW - Betriebliches Informationssystem KW - Datensicherung KW - Literaturbericht Y1 - 2019 UR - http://www.sciencesphere.org/ijispm/archive/ijispm-070102.pdf U6 - https://doi.org/10.12821/ijispm070102 SN - 2182-7796 SN - 2182-7788 SN - 2182-780X VL - 7 IS - 1 SP - 15 EP - 43 ER - TY - JOUR A1 - Klotz, Stefan A1 - Westner, Markus A1 - Strahringer, Susanne T1 - Critical Success Factors of Business-managed IT: It Takes Two to Tango JF - Information Systems Management N2 - This paper identifies critical success factors of Business-managed IT based on case study results. Four groups of critical success factors emerge: (1) general approach to Business-managed IT/Business-managed IT strategy, (2) Business-managed IT project prerequisites/Business-managed IT team, (3) Business-managed IT project execution and outcome, and (4) information technology management for Business-managed IT. The results suggest that bilateral responsibility between the business unit and the IT organization is the most favorable governance option for Business-managed IT. KW - Betriebliches Informationssystem KW - Strategisches Management KW - Erfolgsfaktor KW - Fallstudie KW - Business-managed IT KW - Shadow IT KW - critical success factors KW - IT governance KW - application governance Y1 - 2022 U6 - https://doi.org/10.1080/10580530.2021.1938300 VL - 39 IS - 3 SP - 220 EP - 240 PB - Taylor&Francis ER - TY - JOUR A1 - Borg, Leise A1 - Jørgensen, Jakob Sauer A1 - Frikel, Jürgen A1 - Sporring, Jon T1 - Reduction of variable-truncation artifacts from beam occlusion during in situ x-ray tomography JF - Measurement Science and Technology N2 - Many in situ x-ray tomography studies require experimental rigs which may partially occlude the beam and cause parts of the projection data to be missing. In a study of fluid flow in porous chalk using a percolation cell with four metal bars drastic streak artifacts arise in the filtered backprojection (FBP) reconstruction at certain orientations. Projections with non-trivial variable truncation caused by the metal bars are the source of these variable-truncation artifacts. To understand the artifacts a mathematical model of variable-truncation data as a function of metal bar radius and distance to sample is derived and verified numerically and with experimental data. The model accurately describes the arising variable-truncation artifacts across simulated variations of the experimental setup. Three variable-truncation artifact-reduction methods are proposed, all aimed at addressing sinogram discontinuities that are shown to be the source of the streaks. The 'reduction to limited angle' (RLA) method simply keeps only non-truncated projections; the 'detector-directed smoothing' (DDS) method smooths the discontinuities; while the 'reflexive boundary condition' (RBC) method enforces a zero derivative at the discontinuities. Experimental results using both simulated and real data show that the proposed methods effectively reduce variable- truncation artifacts. The RBC method is found to provide the best artifact reduction and preservation of image features using both visual and quantitative assessment. The analysis and artifact-reduction methods are designed in context of FBP reconstruction motivated by computational efficiency practical for large, real synchrotron data. While a specific variable- truncation case is considered, the proposed methods can be applied to general data cut-offs arising in different in situ x-ray tomography experiments. KW - computed tomography KW - COMPUTED-TOMOGRAPHY KW - CT KW - filtered backprojection KW - IMAGE-RECONSTRUCTION KW - in situ measurements KW - sinogram discontinuities KW - variable-truncation artifacts Y1 - 2017 U6 - https://doi.org/10.1088/1361-6501/aa8c27 VL - 28 IS - 12 PB - IOP Publishing ER - TY - CHAP A1 - Joblin, Mitchell A1 - Mauerer, Wolfgang A1 - Apel, Sven A1 - Siegmund, Janet A1 - Riehle, Dirk T1 - From Developer Networks to Verified Communities: A Fine-Grained Approach T2 - 2015 IEEE/ACM 37th IEEE International Conference on Software Engineering, 16-24 May 2015, Florence, Italy N2 - Effective software engineering demands a coordinated effort. Unfortunately, a comprehensive view on developer coordination is rarely available to support software-engineering decisions, despite the significant implications on software quality, software architecture, and developer productivity. We present a fine-grained, verifiable, and fully automated approach to capture a view on developer coordination, based on commit information and source-code structure, mined from version-control systems. We apply methodology from network analysis and machine learning to identify developer communities automatically. Compared to previous work, our approach is fine-grained, and identifies statistically significant communities using order-statistics and a community-verification technique based on graph conductance. To demonstrate the scalability and generality of our approach, we analyze ten open-source projects with complex and active histories, written in various programming languages. By surveying 53 open-source developers from the ten projects, we validate the authenticity of inferred community structure with respect to reality. Our results indicate that developers of open-source projects form statistically significant community structures and this particular view on collaboration largely coincides with developers' perceptions of real-world collaboration. KW - collaboration KW - Computer languages KW - Measurement KW - Open Source Software KW - Software systems KW - Standards Y1 - 2015 SN - 978-1-4799-1934-5 U6 - https://doi.org/10.1109/icse.2015.73 SP - 563 EP - 573 PB - IEEE ER -