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Die Studie untersucht den Zusammenhang der Fähigkeit zur historischen Perspektivenübernahme mit der Fähigkeit zum historischen Urteilen und Argumentieren bei Schülerinnen und Schülern. Mittels quantitativer Inhaltsanalyse wurden 58 Schülertexte hinsichtlich der gezeigten historischen Perspektivenübernahme und hinsichtlich ihrer Argumentationsqualität mit Hilfe der SOLO-Taxonomie von Biggs und Collis (1982) analysiert. Dabei zeigte sich ein signifikanter Zusammenhang der Argumentationsqualität mit dem Niveau der geleisteten historischen Perspektivenübernahme.
Mit Hilfe eines quasiexperimentellen Designs wurde die Entwicklung von wissenschaftlichen Vorstellungen im Anfangsunterricht des Faches Chemie an Realschulen untersucht. Die kontextorientierte Unterrichtsform „Chemie im Kontext“ (ChiK) wurde traditionellem Unterricht gegenübergestellt. Über 900 Lernende wurden im Zeitraum von etwa sechs Monaten dreimal befragt. Neben den Vorstellungen zum Verbrennungsvorgang wurden weitere Variablen wie z. B. das Interesse für das Fach Chemie erhoben. Die Ergebnisse deuten darauf hin, dass Unterricht nach ChiK dazu geeignet sein kann, Konzeptwandelprozesse zu unterstützen. Insbesondere Mädchen konnten von dem Treatment profitieren. Im Hinblick auf die Entwicklung des Fachinteresses konnten hingegen keine Vorteile festgestellt werden. Gerade die Mädchen, die nach ChiK unterrichtet wurden, verloren während der Laufzeit des Treatments an Interesse.
Hinsichtlich integrierender oder inkludierender Unterrichtsverfahren stehen Lehrkräfte vor der Herausforderung, die Anforderungen von Minderheiten im Klassenverband zu berücksichtigen. Am gegenüberliegenden Ende des durch etwaige Behinderungen eingeschränkten Leistungsspektrums steht die Gruppe der hochleistenden Schülerinnen und Schüler Hochleistung resultiert dabei aus dem synergetischen Zusammenwirken unterschiedlicher Faktoren zur Realisierung eines zugrunde liegenden Begabungspotentials, das als viables Konstrukt angesehen wird. Im Rahmen der hier dargestellten Studie wurden hochleistende Schülerinnen und Schüler der Sekundarstufe II in Bezug auf ihr Persönlichkeitsprofil, ihre Interessen, beliefs und Leistungen im Fach Mathematik hin untersucht. Zum Abgleich wurden zusätzlich Lehrer/innen-Interviews durchgeführt sowie historische empirische Daten verwendet. In der Gegenüberstellung zeigt sich ein spezifisches Auseinanderklaffen der Persönlichkeits- und Leistungsprofile mathematisch Hochleistender und potenziell mathematisch Begabter; u.a. erzielen die nach klassischen Merkmalen („Interesse“, „Ästhetik“, „Spielen“ und „Selbständig“) ausgewählten potenziell mathematisch begabten Schülerinnen und Schüler innerhalb der Hochleistungs-Stichprobe tatsächlich die höchsten Leistungswerte.
INHALTSVERZEICHNIS Ausgabe 2013/2014
Jutta Mägdefrau:
Einführung in das Themenheft 5
BEITRÄGE AUS DER EMPIRISCHEN LEHR-LERN-FORSCHUNG AN DER UNIVERSITÄT PASSAU
Matthias Brandl:
Hochleistung versus Hochbegabung im Mathematikunterricht der Sekundarstufe II 7
Barbara Hank:
Vorstellungen zum Verbrennungsprozess – Entwicklung wissenschaftlicher Konzepte bei Schülerinnen und Schülern 18
Katharina Jonas:
Historische Perspektivenübernahme von Schülerinnen und Schülern beim historischen Urteilen und Argumentieren 30
Manuel Stinglhammer, Hans Mendl:
Religiöses Lernen kann man sehen?! Ein empirisches Unterrichtsforschungsprojekt im Katholischen Religionsunterricht 42
LEHRER(BILDUNGS)FORSCHUNG
Sabrina Kufner:
Was ist adaptives Lehren und wie lässt sich dessen Qualität empirisch erfassen? 55
Jutta Mägdefrau, Petia Genkova:
Der Zusammenhang von kultureller Distanz, kultureller Anpassung und beruflichem Belastungserleben: Eine
Studie zum Gelingen der Entsendung von Lehrkräften im deutschen Auslandsschulwesen 68
Guido Pollak, Martina Schliessleder:
„Wie ich wurde, was ich bin“ – Biographiearbeit im Professionalisierungsprozess 85
QUALIFIKATIONSARBEIT AUS DEM BEREICH DER EMPIRISCHEN LERNFORSCHUNG
Isolde Baumgartner:
Einfluss von Fachinteresse auf situationales Interesse bei der Bearbeitung von Aufgaben im Fach Geschichte. Eine Treatment-Studie mit Variation der Aufgabeninteressantheit am Beispiel „Deutscher Widerstand im Nationalsozialismus“ 105
ZUR DISKUSSION
Hans-Michael Körner:
„Abholen“ – ein deutsches Lieblingswort 117
Bei dem Forschungsprojekt, auf das sich diese Datendokumentation bezieht, geht es um die Erfassung des Rezeptionsverhaltens im Museum. Dazu wurden Probanden gebeten, während des Besuchs der ersten sieben Räume im Museum Veste Oberhaus in Passau die Gedanken zu verbalisieren, die ihnen beim Betrachten der Objekte durch den Kopf gingen. Die Verbaltranskripte der Tonaufnahmen zum Lauten Denken sind hier abgedruckt und stehen der Forschung zur Verfügung zusammen mit den Fotografien der Museumsobjekte aus diesen Räumen.
Over the last two decades, the Internet has fundamentally changed the ways firms and consumers interact. The ongoing evolution of the Internet-enabled market environment entails new challenges for marketing research and practice, including the emergence of innovative business models, a proliferation of marketing channels, and an unknown wealth of data. This dissertation addresses these issues in three individual essays. Study 1 focuses on business models offering services for free, which have become increasingly prevalent in the online sector. Offering services for free raises new questions for service providers as well as marketing researchers: How do customers of free e-services contribute value without paying? What are the nature and dynamics of nonmonetary value contributions by nonpaying customers? Based on a literature review and depth interviews with senior executives of free e-service providers, Study 1 presents a comprehensive overview of nonmonetary value contributions in the free e-service sector, including not only word of mouth, co-production, and network effects but also attention and data as two new dimensions, which have been disregarded in marketing research. By putting their findings in the context of existing literature on customer value and customer engagement, the authors do not only shed light on the complex processes of value creation in the emerging e-service industry but also advance marketing and service research in general. Studies 2 and 3 investigate the analysis of online multichannel consumer behavior in times of big data. Firms can choose from a plethora of channels to reach consumers on the Internet, such that consumers often use a number of different channels along the customer journey. While the unprecedented availability of individual-level data enables new insights into multichannel consumer behavior, it also makes high demands on the efficiency and scalability of research approaches. Study 2 addresses the challenge of attributing credit to different channels along the customer journey. Because advertisers often do not know to what degree each channel actually contributes to their marketing success, this attribution challenge is of great managerial interest, yet academic approaches to it have not found wide application in practice. To increase practical acceptance, Study 2 introduces a graph-based framework to analyze multichannel online customer path data as first- and higher-order Markov walks. According to a comprehensive set of criteria for attribution models, embracing both scientific rigor and practical applicability, four model variations are evaluated on four, large, real-world data sets from different industries. Results indicate substantial differences to existing heuristics such as “last click wins” and demonstrate that insights into channel effectiveness cannot be generalized from single data sets. The proposed framework offers support to practitioners by facilitating objective budget allocation and improving team decisions and allows for future applications such as real-time bidding. Study 3 investigates how channel usage along the customer journey facilitates inferences on underlying purchase decision processes. To handle increasing complexity and sparse data in online multichannel environments, the author presents a new categorization of online channels and tests the approach on two large clickstream data sets using a proportional hazard model with time-varying covariates. By categorizing channels along the dimensions of contact origin and branded versus generic usage, Study 3 finds meaningful interaction effects between contacts across channel types, corresponding to the theory of choice sets. Including interactions based on the proposed categorization significantly improves model fit and outperforms alternative specifications. The results will help retailers gain a better understanding of customers’ decision-making progress in an online multichannel environment and help them develop individualized targeting approaches for real-time bidding. Using a variety of methods including qualitative interviews, Markov graphs, and survival models, this dissertation does not only advance knowledge on analyzing and managing online consumer behavior but also adds new perspectives to marketing and service research in general.
Following an “agency-oriented Urban Theory” as advanced by Smith (2001), this study takes the urban landscape of Vinh City in Central Vietnam as a starting point into an investigation of multiple visions of modernity (Eisenstadt, 2000) put forward by social actors, as well as into urban change resulting from the implementation of such visions. Focusing on the period from 1973 to 2011, it traces the application of three different visions for urban development in Vinh: The Socialist City, The Modern and Civilized City, and the Participatory City. Projects aiming at implementing these visions in Vinh that are presented in this study have one thing in common: they are informed by a specific view of what a city is and what it should be, and their implementation aims at changing the city in the desired direction. This goal involves not only physical change of the city, but also institutional change in the urban society. To grasp the interplay between visions of a modern city, their application through concrete projects, and the results of these implementations, the study operates with two specific terms: modern projects, and urban change. After introducing Vinh and its history, the thesis presents the period of the vision of The Socialist City and its application in Vinh through cooperation between Vietnam and the German Democratic Republic in the 1970s. It then moves on to contemporary period starting in the 1990s, during which varying and conflicting modern projects for the city were put forward by different social actors cooperating in joint projects on urban development: the Modern and Civilized City and the Participatory City. While the modes of cooperation differed between the two periods, the study concludes with the argument that the impact of these transnational projects has led to path-dependent, as well as ambivalent, urban change in Vinh.
In this thesis, we investigates plane drawings of undirected and directed graphs on cylinder surfaces. In the case of undirected graphs, the vertices are positioned on a line that is parallel to the cylinder’s axis and the edge curves must not intersect this line. We show that a plane drawing is possible if and only if the graph is a double-ended queue (deque) graph, i. e., the vertices of the graph can be processed according to a linear order and the edges correspond to items in the deque inserted and removed at their end vertices. A surprising consequence resulting from these observations is that the deque characterizes planar graphs with a Hamiltonian path. This result extends the known characterization of planar graphs with a Hamiltonian cycle by two stacks. By these insights, we also obtain a new characterization of queue graphs and their duals. We also consider the complexity of deciding whether a graph is a deque graph and prove that it is NP-complete. By introducing a split operation, we obtain the splittable deque and show that it characterizes planarity. For the proof, we devise an algorithm that uses the splittable deque to test whether a rotation system is planar. In the case of directed graphs, we study upward plane drawings where the edge curves follow the direction of the cylinder’s axis (standing upward planarity; SUP) or they wind around the axis (rolling upward planarity; RUP). We characterize RUP graphs by means of their duals and show that RUP and SUP swap their roles when considering a graph and its dual. There is a physical interpretation underlying this characterization: A SUP graph is to its RUP dual graph as electric current passing through a conductor to the magnetic field surrounding the conductor. Whereas testing whether a graph is RUP is NP-hard in general [Bra14], for directed graphs without sources and sink, we develop a linear-time recognition algorithm that is based on our dual graph characterization of RUP graphs.
Diese Arbeit untersucht, wie Privatinvestoren vorzeitige Kündigungsrechte in strukturierten Zinsprodukten nutzen. Als Grundlage für die Analyse dient hierbei ein neuartiger, nicht öffentlich verfügbarer Datensatz, der über einen Zeitraum von circa 13 Jahren Entscheidungen von mehr als 800.000 Privatinvestoren über ein weiteres Halten oder eine vorzeitige Kündigung von Putable Bonds (Bundesschatzbriefen) abbildet. Das Ziel der Arbeit ist es, das Verständnis von finanziellen Entscheidungsstrategien von Privatinvestoren theoretisch und empirisch zu erweitern sowie mögliche Unterschiede innerhalb dieser Investorengruppe und im Vergleich zu anderen Kapitalmarktakteuren zu identifizieren. Darüber hinaus soll die Arbeit mögliche Handlungsfelder für Emittenten und Banken, welche vergleichbare Finanzprodukte anbieten, aufzeigen.
Auf mediensemiotischer Grundlage erschließt der Beitrag erstmals theoretisch die für die 1990er und 2000er Jahre stilbildende Short Cuts-Narration, wie sie in der Folge von Robert Altmans gleichnamigem Film u.a. für Pulp Fiction, Magnolia, Babel, Amores Perros, L.A. Crash oder Love Actually und Cloud Atlas, aber auch für eine Vielzahl von literarischen Texten der Gegenwart ästhetisch prägend wurde. Die Erzählweise wird definiert, hinsichtlich ihrer Funktion in den Bedeutungskonstrukten systematisiert und in ihrer historischen Genese betrachtet, wobei 'Fragmentierung' und 'Vernetzung' als zentrale Paradigmen der Short Cuts-Narration auch im Kontext von Moderne und Postmoderne verortet werden. Kontrapunktisch behandelt der Beitrag zudem filmische Literaturfiktionen und deren semantische Funktionen.
Das deutsche Notwehrrecht weist ein bedeutsames Spezifikum auf. Im Gegensatz zu den §§ 228, 904 BGB und vielen ausländischen Rechtsordnungen, verlangt § 32 StGB prinzipiell keine Güterabwägung. Das sich durch das Merkmal der Erforderlichkeit manifestierende Übermaßverbot setzt weder eine Güterproportionalität zwischen den rechtlichen Interessen des Angegriffenen und denen des Angreifers noch eine Schadensproportionalität voraus. Die Tatsache, dass 32 StGB keine Güterabwägung vorsieht, wirft zahlreiche Fragen auf. Ist dies als ein ernsthaftes Manko des Notwehrrechts zu verstehen, oder sind bestimmte Lösungen vorstellbar, die ggf. von einer gewissen Einschränkung des Notwehrrechts ausgehen? Wenn solche Einschränkungen in Frage kommen, nach welchen Kriterien könnte man sie bestimmen? Wo liegen die Grenzen etwaiger Schranken des Notwehrrechts? Geht es dabei um festgesetzte und änderungsfeste Grenzen? Können vieleicht neue, zusätzliche Konstellationen in Betracht gezogen werden, die diese Grenzen noch erweitern können? Das Ziel der vorliegenden Untersuchung ist es, entsprechende Antworten auf die oben gestellten Fragen anzubieten. Die vorliegende Untersuchung gliedert sich in sechs Kapitel. Nach der Problemstellung und der einführenden Abhandlung zur Notwehr als Strafrechtsbegriff werden die allgemeinen Fragen der sog. sozialethischen Einschränkungen des Notwehrrechts behandelt. Im Anschluss daran werden die Aspekte des Schutzes von Eigentum im Falle der sog. Bagatellangriffe erörtert. Danach werden die Einschränkungen des Notwehrrechts aus verfassungsrechtlichen Gründen untersucht. Schließlich werden im Rahmen der Untersuchung auch andere sozialethische Einschränkungen der Notwehr und darunter eine besonders intensiv diskutierte Fallgruppe der sog. Notwehrprovokation behandelt. Im Rahmen der Schlussbetrachtung werden die gewonnenen Ergebnisse noch einmal zusammengefasst dargestellt.
Modern Web technology makes the dream of fully interactive and enriched video come true. Nowadays it is possible to organize videos in a non-linear way playing in a sequence unknown in advance. Furthermore, additional information can be added to the video, ranging from short descriptions to animated images and further videos. This affords an easy and efficient to use authoring tool which is capable of the management of the single media objects, as well as a clear arrangement of the links between the parts. Tools of this kind can be found rarely and do mostly not provide the full range of needed functions. While providing an interactive experience to the viewer in the Web player, parallel plot sequences and additional information lead to an increased download volume. This may cause pauses during playback while elements have to be downloaded which are displayed with the video. A good quality of experience for these videos with small waiting times and a playback without interruptions is desired. This work presents the SIVA Suite to create the previously described annotated interactive non-linear videos. We propose a video model for interactivity, non-linearity, and annotations, which is implemented in an XML format, an authoring tool, and a player. Video is the main medium, whereby different scenes are linked to a scene graph. Time controlled additional content called annotations, like text, images, audio files, or videos, is added to the scenes. The user is able to navigate in the scene graph by selecting a button at a button panel. Furthermore, other navigational elements like a table of contents or a keyword search are provided. Besides the SIVA Suite, this thesis presents algorithms and strategies for download and cache management to provide a good quality of experience while watching the annotated interactive non-linear videos. Therefor, we implemented a standard-independent player framework. Integrated into a simulation environment, the framework allows to evaluate algorithms and strategies for the calculation of start-up times, and the selection of elements to pre-fetch into and delete from the cache. Their interaction during the playback of non-linear video contents can be analyzed. The algorithms and strategies can be used to minimize interruptions in the video flow after user interactions. Our extensive evaluation showed that our techniques result in faster start-up times and lesser interruptions in the video flow than those of other players. Knowledge of the structure of an interactive non-linear video can be used to minimize the start-up time at the beginning of a video while minimizing an increase in the overall download volume.
In the Web 2.0 era, platforms for sharing and collaboratively annotating images with keywords, called tags, became very popular. Tags are a powerful means for organizing and retrieving photos. However, manual tagging is time consuming. Recently, the sheer amount of user-tagged photos available on the Web encouraged researchers to explore new techniques for automatic image annotation. The idea is to annotate an unlabeled image by propagating the labels of community photos that are visually similar to it. Most recently, an ever increasing amount of community photos is also associated with location information, i.e., geotagged. In this thesis, we aim at exploiting the location context and propose an approach for automatically annotating geotagged photos. Our objective is to address the main limitations of state-of-the-art approaches in terms of the quality of the produced tags and the speed of the complete annotation process. To achieve these goals, we, first, deal with the problem of collecting images with the associated metadata from online repositories. Accordingly, we introduce a strategy for data crawling that takes advantage of location information and the social relationships among the contributors of the photos. To improve the quality of the collected user-tags, we present a method for resolving their ambiguity based on tag relatedness information. In this respect, we propose an approach for representing tags as probability distributions based on the algorithm of Laplacian score feature selection. Furthermore, we propose a new metric for calculating the distance between tag probability distributions by extending Jensen-Shannon Divergence to account for statistical fluctuations. To efficiently identify the visual neighbors, the thesis introduces two extensions to the state-of-the-art image matching algorithm, known as Speeded Up Robust Features (SURF). To speed up the matching, we present a solution for reducing the number of compared SURF descriptors based on classification techniques, while the accuracy of SURF is improved through an efficient method for iterative image matching. Furthermore, we propose a statistical model for ranking the mined annotations according to their relevance to the target image. This is achieved by combining multi-modal information in a statistical framework based on Bayes' rule. Finally, the effectiveness of each of mentioned contributions as well as the complete automatic annotation process are evaluated experimentally.
Making multimedia data available online becomes less expensive and more convenient on a daily basis. This development promotes web phenomenons such as Facebook, Twitter, and Flickr. These phenomena and their increased acceptance in society in turn leads to a multiplication of the amount of available images online. This vast amount of, frequently public and therefore searchable, images already exceeds the zettabyte bound. Executing a similarity search on the magnitude of images that are publicly available in the Internet, and receiving a top quality result is a challenge that the scientific community has recently attempted to rise to. One approach to cope with this problem assumes the use of distributed heterogeneous Content Based Image Retrieval system (CBIRs). Following from this anticipation, the problems that emerge from a distributed query scenario must be dealt with. For example the involved CBIRs’ usage of distinct metadata formats for describing their content, as well as their unequal technical and structural information. An addition issue is the individual metrics that are used by the CBIRs to calculate the similarity between pictures, as well as their specific way of being combined. Overall, receiving good results in this environment is a very labor intensive task which has been scientifically but not yet comprehensively explored. The problem primarily addressed in this work is the collection of pictures from CBIRs, that are similar to a given picture, as a response to a distributed multimedia query. The main contribution of this thesis is the construction of a network of Content Based Image Retrieval systems that are able to extract and exploit the information about an input image’s semantic concept. This so called semantic CBIRn is mainly composed of CBIRs that are configured by the semantic CBIRn itself. Complementarily, there is a possibility that allows the integration of specialized external sources. The semantic CBIRn is able to collect and merge results of all of these attached CBIRs. In order to be able to integrate external sources that are willing to join the network, but are not willing to disclose their configuration, an algorithm was developed that approximates these configurations. By categorizing existing - as well as external - CBIRs and analyzing incoming queries, image queries are exclusively forwarded to the most suitable CBIRs. In this way, images that are not of any use for the user can be omitted beforehand. The hereafter returned images are rendered comparable in order to be able to merge them to one single result list of images, that are similar to the input image. The feasibility of the approach and the hereby obtained improvement of the search process is demonstrated by a prototypical implementation and its evaluation using classified images of ImageNet. Using this prototypical implementation an augmentation of the number of returned images that are of the same semantic concept as the input images is achieved by a factor of 4.75 with respect to a predefined non-semantic CBIRn.
UME is the notion that a user should receive informative adapted content anytime and anywhere. Personalization of videos, which adapts their content according to user preferences, is a vital aspect of achieving the UME vision. User preferences can be translated into several types of constraints that must be considered by the adaptation process, including semantic constraints directly related to the content of the video. To deal with these semantic constraints, a fine-grained adaptation, which can go down to the level of video objects, is necessary. The overall goal of this adaptation process is to provide users with adapted content that maximizes their Quality of Experience (QoE). This QoE depends at the same time on the level of the user's satisfaction in perceiving the adapted content, the amount of knowledge assimilated by the user, and the adaptation execution time. In video adaptation frameworks, the Adaptation Decision Taking Engine (ADTE), which can be considered as the "brain" of the adaptation engine, is responsible for achieving this goal. The task of the ADTE is challenging as many adaptation operations can satisfy the same semantic constraint, and thus arising in several feasible adaptation plans. Indeed, for each entity undergoing the adaptation process, the ADTE must decide on the adequate adaptation operator that satisfies the user's preferences while maximizing his/her quality of experience. The first challenge to achieve in this is to objectively measure the quality of the adapted video, taking into consideration the multiple aspects of the QoE. The second challenge is to assess beforehand this quality in order to choose the most appropriate adaptation plan among all possible plans. The third challenge is to resolve conflicting or overlapping semantic constraints, in particular conflicts arising from constraints expressed by owner's intellectual property rights about the modification of the content. In this thesis, we tackled the aforementioned challenges by proposing a Utility Function (UF), which integrates semantic concerns with user's perceptual considerations. This UF models the relationships among adaptation operations, user preferences, and the quality of the video content. We integrated this UF into an ADTE. This ADTE performs a multi-level piecewise reasoning to choose the adaptation plan that maximizes the user-perceived quality. Furthermore, we included intellectual property rights in the adaptation process. Thereby, we modeled content owner constraints. We dealt with the problem of conflicting user and owner constraints by mapping it to a known optimization problem. Moreover, we developed the SVCAT, which produces structural and high-level semantic annotation according to an original object-based video content model. We modeled as well the user's preferences proposing extensions to MPEG-7 and MPEG-21. All the developed contributions were carried out as part of a coherent framework called PIAF. PIAF is a complete modular MPEG standard compliant framework that covers the whole process of semantic video adaptation. We validated this research with qualitative and quantitative evaluations, which assess the performance and the efficiency of the proposed adaptation decision-taking engine within PIAF. The experimental results show that the proposed UF has a high correlation with subjective video quality evaluation.
Die vorliegende Studie untersucht die Rückwanderungsintention von Arbeitsmigranten in Deutschland unter dem Gesichtspunkt der Lebenszufriedenheit. Am Beispiel von München wird die individuelle Lebenssituation von spanischen Arbeitsmigranten beleuchtet, die seit 2008 nach Deutschland gekommen sind. Denn trotz der wirtschaftlichen Stärke Deutschlands gelingt es oftmals nicht die dringend benötigten ausländischen Fachkräfte auch zu halten. Was also treibt so zahlreiche Zuwanderer wieder zurück? Diese Frage muss dabei immer vor dem Hintergrund betrachtet werden, dass eine Migration immer auch eine Lebensentscheidung darstellt, die sich für den Einzelnen am Ende lohnen soll. Die zentralen Forschungsfragen lauten: • Wie zufrieden sind die spanischen Arbeitsmigranten mit ihrem Leben in Deutschland? • Wie orientieren sie sich in Hinblick auf die Zukunft – Bleiben oder Zurückkehren? • Welches sind die entscheidenden Faktoren dafür? Zur Beantwortung dieser Fragen werden verschiedene Theorien aus der Migrations- und Glücksforschung diskutiert und daraus ein integriertes Erklärungsmodell entwickelt, welches die Grundlage für die empirische Untersuchung bildet. Somit wird das Phänomen Migration nicht nur als Ergebnis einer ökonomisch-rationalen Nutzenabwägung betrachtet, sondern es können auch andere Aspekte berücksichtigt werden – etwa die soziale Einbindung oder persönliche Ziele der Individuen. Die Ergebnisse der Studie werden in einem aus der qualitativen Analyse hervorgegangenen Kategoriensystem aufbereitet und mit Ankerbeispielen und Zitaten veranschaulicht. Abschließend erfolgt die Interpretation der Ergebnisse, wobei sich herausstellt, dass den nicht-ökonomischen Faktoren bei der Rückwanderungsentscheidung von Arbeitsmigranten die weit größere Rolle zukommt.
The present thesis is based on four articles in the areas of labor economics, regional science and international trade. I make use of different micro-level data sets to evaluate reasons for performance disparities between firms and between workers and evaluate the interrelation of these disparities with characteristics of local labor markets. Chapter 1 of this thesis provides a discrimination between the effects of several agglomeration externalities on firms’ total factor productivity. The identification of TFP is not trivial, however. I thereby correct for biases due to unobserved output prices and the endogeneity of agglomeration economies. Traditional reasons, such as specialization, diversity and size of the county, as well as the more detailed Marshallian agglomeration economies, namely knowledge spillovers and labor market pooling, are jointly tested. It turns out that labor market pooling is the quantitatively most important agglomeration mechanism. It is captured by the correlation of the occupational composition between one county-industry and the rest of the county. The intuition behind it is that a plant readily finds suitable staff if sectors, which employ similar workers, have a large extent in the same region. Labor market pooling is still the dominant agglomeration force if the spatial boundaries of regions are changed. In general, the data demonstrate that the strength of agglomeration economies varies largely between sectors. Only for a subset of industries, some positive evidence is detected for knowledge spillovers. Chapter 2 analyzes labor market pooling in greater detail, but with a slightly different modeling than in chapter 1. Here, the central aspect of labor market pooling is based on the quality of workers and firms. The main questions are if there is a systematic matching in the labor market and if this matching pattern creates advantages for both parties. I devote attention to the identification of accurate quality measures: plants' total factor productivity and workers' fixed effect. Two different methods then yield evidence in favor of positive assortative matching. The correlation between both quality measures is positive. Wage gains amount up to 4% when both quality levels are equal. In a fairly general matching model, this shape of the wage curve arises due to complementarities of qualities in the production function. When generally higher productivities and wages in dense regions (caused by agglomeration economies and sorting) are not controlled for, the strength of matching and wage gains are overestimated. I also find that regional differences in matching quality cannot be attributed to the local density and unemployment rate. Chapter 3 applies several regression-based decomposition methods to analyze the impact of region-, worker-, firm- and sector-specific determinants on the wage level and the continuous increase in wage inequality between 1995 and 2007 in Germany. In contrast to prior studies, more than 50% of the wage dispersion and almost the entire increase in wage inequality are explained in this approach. Altogether, the entire growth of wage dispersion occurs within regions and changes in the composition of wage determinants are minor compared to changes in their returns. I find that occupational attributes are the most important wage determinant. Changes in the firm size premium in combination with assortative matching also depress wages in the bottom of the distribution while they increase wages at the top. Workers with an unemployment record or an occupation in the service, construction and logistics sectors particularly experience falling wages. Chapter 4 studies the effect of an expansion of imported intermediate inputs on establishments’ average task intensities and employment size in a middle-income country. I use confidential matched employer-employee data and information on trade transactions for the universe of Brazilian firms. Propensity Score Matching indicates that import expansion leads to an overall employment growth, higher intensities in routine and non-routine manual tasks and an increased share of intermediates exports. Thus my findings point out that intermediates imports represent onshored instead of offshored tasks. This result remains unchanged regardless of whether imports from high- or low-wage countries are considered.
Embedded networks are fundamental infrastructures of many different kinds of domains, such as home or industrial automation, the automotive industry, and future smart grids. Yet they can be very heterogeneous, containing wired and wireless nodes with different kinds of resources and service capabilities, such as sensing, acting, and processing. Driven by new opportunities and business models, embedded networks will play an ever more important role in the future, interconnecting more and more devices, even from other network domains. Realizing applications for such types of networks, however, is a highly challenging task, since various aspects have to be considered, including communication between a diverse assortment of resource-constrained nodes, such as microcontrollers, as well as flexible node infrastructure. Service Oriented Architecture (SOA) with Web services would perfectly meet these unique characteristics of embedded networks and ease the development of applications. Standardized Web services, however, are based on plain-text XML, which is not suitable for microcontroller-based devices with their very limited resources due to XML's verbosity, its memory and bandwidth usage, as well as its associated significant processing overhead. This thesis presents methods and strategies for realizing efficient XML-based Web service communication in embedded networks by means of binary XML using EXI format. We present a code generation approach to create optimized and dedicated service applications in resource-constrained embedded networks. In so doing, we demonstrate how EXI grammar can be optimally constructed and applied to the Web service and service requester context. In addition, so as to realize an optimized service interaction in embedded networks, we design and develop an optimized filter-enabled service data dissemination that takes into account the individual resource capabilities of the nodes and the connection quality within embedded networks. We show different approaches for efficiently evaluating binary XML data and applying it to resource constrained devices, such as microcontrollers. Furthermore, we will present the effectful placement of binary XML filters in embedded networks with the aim of reducing both, the computational load of constrained nodes and the network traffic. Various evaluation results of V2G applications prove the efficiency of our approach as compared to existing solutions and they also prove the seamless and successful applicability of SOA-based technologies in the microcontroller-based environment.
Veränderung ist gegenwärtig das dominierende Kennzeichen der berufsschulischen Steuerungskultur in Bayern. Das starre, stahlharte Gehäuse der bürokratischen Input-Steuerung wird abgelöst durch flexible Netze, innerhalb derer sich die Akteure der Doppelhelix-Struktur des dualen Systems bewegen. Für die Berufsschulleiter, die von diesen veränderten Rahmenbedingungen in ihren Handlungsräumen unmittelbar betroffen sind, liegen bis dato keine wissenschaftlichen Untersuchungen vor. Die vorliegende qualitative Studie schließt diese Forschungslücke, indem sie die Deutungsstrukturen auf der Ebene von Berufsschulleitern bei der Transformation von einer verwalteten Schule hin zu einer eigenständigeren Schule untersucht. Die Arbeit geht hierbei von den theoretischen Konzepten der Rollenanalyse im bürokratischen System nach Weber, Buschors Merkmalen des New Public Management, Parsons Modell der Mustervariablen und dem Konzept der Rekontextualisierung nach Fend aus und untersucht anhand von leitfadengestützten, halbstandardisierten Experteninterviews sowohl die gegenwärtigen als auch die auf die Zukunft gerichteten Wahrnehmungen und Erwartungshaltungen der relevanten Akteure des dualen Systems. Die Operationalisierung der Fragestellung erfolgt hierbei über die Untersuchung von verschiedenen Kontexten der Eigenständigkeit. Anhand der sechs analysierten Bereiche des Schulsystems, der Organisations-, Personal-, und Unterrichtsentwicklung sowie des Budgets und der Qualitätssicherung werden die Erwartungshaltungen der Berufsschulleiter untersucht und mit den Fremderwartungen der Akteure aus der Doppelhelix-Struktur des dualen Systems gespiegelt. Insgesamt zeigen die Ergebnisse für alle Bereiche sowohl ein verändertes Steuerungs- und Rollenverständnis der Berufsschulleiter als auch einen Zugewinn hinsichtlich der strukturellen Freiräume in den Handlungsoptionen der Berufsschulleiter, die sich in den Deutungsstrukturen niederschlagen. Die Veränderungen in den Perzeptionen und Deutungsstrukturen sind in einer quantitativen Anschlussstudie durch die Entwicklung neuer typologischer Profile von Berufsschulleitern empirisch zu begleiten, um passgenaue universitäre Fortbildungsangebote für pädagogische Führungskräfte entwickeln zu können.
Multimedia retrieval is an essential part of today's world. This situation is observable in industrial domains, e.g., medical imaging, as well as in the private sector, visible by activities in manifold Social Media platforms. This trend led to the creation of a huge environment of multimedia information retrieval services offering multimedia resources for almost any user requests. Indeed, the encompassed data is in general retrievable by (proprietary) APIs and query languages, but unfortunately a unified access is not given due to arising interoperability issues between those services. In this regard, this thesis focuses on two application scenarios, namely a medical retrieval system supporting a radiologist's workflow, as well as an interoperable image retrieval service interconnecting diverse data silos. The scientific contribution of this dissertation is split in three different parts: the first part of this thesis improves the metadata interoperability issue. Here, major contributions to a community-driven, international standardization have been proposed leading to the specification of an API and ontology to enable a unified annotation and retrieval of media resources. The second part issues a metasearch engine especially designed for unified retrieval in distributed and heterogeneous multimedia retrieval environments. This metasearch engine is capable of being operated in a federated as well as autonomous manner inside the aforementioned application scenarios. The remaining third part ensures an efficient retrieval due to the integration of optimization techniques for multimedia retrieval in the overall query execution process of the metasearch engine.