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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
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.
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.
Religiöse Lernprozesse sollen in dieser Studie auf mikrostruktureller Ebene beleuchtet werden. Dabei bilden die Schwierigkeiten der Lehr-Lernforschung im Kontext des katholischen Religionsunterrichts und die Notwendigkeit einer adäquaten Begriffsbestimmung den Ausgangspunkt. Mit Hilfe von videografierten Unterrichtsaufzeichnungen, Interviews mit den Lernenden und den Lehrkräften wird der Frage nachgegangen, wie sich die Lernprozesse von Schülerinnen und Schüler gestalten. Wesentliche Erkenntnis infolge inhaltsanalytischer Auswertungsmethodik ist, dass Lehrende eher eindimensionale Verknüpfungsleistungen einfordern, komplexere Vernetzungsleistungen mit anderen Themen oder biblischen Erzählungen kaum anregen. Wenn Schülerinnen und Schüler trotzdem zu umfassenderen Verknüpfungen kommen, werden diese für weitere Lernprozesse in der Klasse kaum nutzbar gemacht. Die Kommunikation verbleibt meist auf der Ebene eines Lehrer-Schüler-Gespräches, eine Verständigung zwischen den Schülern ist selten.
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.
Advocated by leading consulting firms, the concept of value-based management has enjoyed popularity and found its way into corporate practice in the mid 1990s. But the large breakthrough of value-based management held off, especially in the German landscape. The following four documents first analyze the status quo of value-based management in board compensation, second analyze performance effects of value-based management implementations, third investigate the reasons why inconsistent implementations of value-based management might exist and fourth, the effects of investor relations activities on corporate stock.
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.
Rudolf Wimmer (*1849 in Gottsdorf, Ndb., +1915 in München) war Hofmaler des letzten deutschen Kaisers Wilhelm II. und der bayerisch-wittelsbachischen Königsfamilie. Darüber hinaus galt er als anerkannter Münchner Gesellschaftsmaler der zweiten Hälfte des 19. Jahrhunderts. Als einzigartig gilt Wimmers Schaffen zum Themenbereich der Herstellung von Glas und optischen Instrumenten im Zusammenhang mit Joseph von Fraunhofer und der Optikerfamilie Merz, zu der er durch die Heirat seiner zweiten Frau Barbara Wimmer, geborene Merz, in verwandtschaftlicher Beziehung stand. „Der Kaisermaler. Rudolf Wimmer 1849-1915“ geht neben der Porträtisten-Tätigkeit Wimmers am preußischen und bayerischen Hof auch umfassend auf die Lebensumstände des Künstlers ein und stellt ihn neben seiner Beschäftigung in der Porträt- und Genremalerei erstmals auch als Landschafter und Maler sakraler Themen der Öffentlichkeit vor. Zudem beschäftigt sich die Arbeit im letzten Abschnitt eingehend mit der „Hofkunst“ unter Kaiser Wilhelm II. und versucht einen qualitativ-stilistischen Vergleich der bekanntesten Porträts des Kaisers aus der Hand unterschiedlicher Künstler.
The Internet is a global system of interconnected computers and computer networks where semi-structured data has been successfully applied for exchanging information. In nowadays Internet the huge range of actors, the large diversity of the associated device classes and domains, and the enormous amount of resource-restricted controllers in this system created new requirements and coined also a new term. Internet of Things (IoT), in this regard, refers to identifiable objects (things) and their virtual representations in an Internet-like structure. The fundamental question the thesis tries to answer is whether and how the same semi-structured data can be also applied to the IoT and the embedded domain in spite of resource-limited controllers. In order to discuss this question properties and requirements of embedded networks with regard to the IoT domain have been collected and evaluated. Thereafter the omnipresent semi-structured data exchange format in the Web, the Extensible Markup Language (XML), has been validated. The result was a list of missing requirements such as a compact representation, a representation that can be generated and consumed fast and also allows a small footprint implementation. To address the compiled requirements a binary representation of XML which nowadays is known as W3Cs Efficient XML Interchange (EXI) format has been accomplished which simultaneously optimizes performance and the utilization of computational resources and is designed to be compatible with XML. Moreover, in this work the format has been practically validated and tested. Addressing the needs of the embedded domain one result of this analyzes were optimizations to constrain runtime memory usage and to predict memory growth at runtime. A concept introduced in this thesis is LazyDOM which reduces memory requirements when processing and querying data. By means of a newly proposed code generation technique processing of EXI on ultra-constrained device classes has been enabled and resulting format modifications have been adopted by the W3C standardization. The research work described in this thesis on efficiently exchanging and processing semi-structured data on constrained embedded devices has not only triggered modifications in the W3C EXI format but even is already adopted in domain specific application standards and implementations. The above mentioned optimizations such as predictably limit the memory growth at runtime have been contributed, discussed and evaluated by the W3C experts and become a core part of the EXI specification. Even more significantly from the IoT perspective these optimizations provide the basis for the adoption of this technology in ISO and IEC standardization which is the first time for automotive and power industry to use IoT in the control plane. The implementation of EXI to conduct the evaluation as part of this thesis has become the de-facto open source reference implementation of EXI and became the basis of a number of other reference implementations such as the OpenV2G project that provides the reference implementation of the communication interface in ISO/IEC 15118. In summary the conducted research work has evaluated the options to adapt semi-structured data for the constrained embedded domain, proposed modifications and evaluated those under realistic conditions. This made it relevant for the technology as well as for application standardization despite the short period of this work. As such the research can now be taken as a basis for further challenges in the IoT field namely adopting concepts of the Semantic Web and adapting those to stimulate the quickly expanding eco-system of embedded devices.
Seit einigen Jahren werden an der Universität Passau in den Lehramtsstudiengängen im Bereich der erziehungswissenschaftlichen Studien spezielle Seminarangebote zum Thema „Biographiearbeit“ angeboten. Entwicklung und Durchführung dieser Seminare stehen im größeren Zusammenhang der theoretischen Grundlegung und Ausarbeitung sowie der ausbildungsorientierten Umsetzung eines Professionalisierungskonzepts für die Lehrerbildung, welches gemeinsam von Vertretern der sog. „4 Säulen“ der Lehrerbildung (Unterrichtsfachwissenschaft,Fachdidaktik, Bildungswissenschaften, schulpraktische Studien) getragen wird. Das angesprochene Professionalisierungskonzept fokussiert die durch die LPO I gesetzten Vorgaben auf ein gemeinsames Leitbild von pädagogischer Professionalität.
Vor dem Hintergrund theoretischer Annahmen zu kultureller Anpassung bei Migrationserfahrungen in kulturell distanten und proximalen Kulturen werden die Befunde einer empirischen Studie bei N = 426 Auslandslehrkräften berichtet. Die Untersuchung versuchte die Frage zu beantworten, ob kulturelle Anpassung eher in proximalen Kulturen gelingt und ob sich berufliche Belastung und berufliche und allgemeine Zufriedenheitswerte bei Lehrkräften in Abhängigkeit von der Gastkultur zeigen lassen. Der Zusammenhang zwischen kultureller Anpassung und Zufriedenheit sowie zwischen kultureller Anpassung und Belastungserleben ließ sich nachweisen. Der Zusammenhang zwischen kultureller Distanz und kultureller Anpassung ergab nur für die nicht-europäischen Länder signifikante Befunde.
Im Rahmen einer Studie zur Diagnose und Prognose von Handlungskompetenz im Bereich adaptiven Lehrens von Studierenden wurde ein Messverfahren entwickelt, das die Lücke zwischen Handlungspräskriptionen in Form empirisch erhobener Dispositionen und dem tatsächlichen Handlungsvollzug schließen kann. Der vorliegende Artikel beschreibt die Entwicklung, Anwendung und Überprüfung des Beobachtungsinstrumentes zur Erhebung „adaptiven Lehrens“. Mit diesem Instrument gelang es, adaptives Lehrerhandeln entlang deduktiv ermittelter Qualitätskriterien empirisch zu erfassen.
Die Studie geht der Frage nach, welchen Einfluss individuelles Fachinteresse auf das aufgabenbezogene situationale Interesse im Unterrichtsfach Geschichte hat. Dabei wurde zwischen zwei Klassen unterschieden. Während die eine Klasse mit ästhetisch manipuliertem Aufgabenmaterial arbeitete, bekam die andere Aufgaben ohne ästhetische Aufwertung. Die Aufgabenstellung war in beiden Klassen dieselbe. An der Studie nahmen 55 bayerische Realschüler/ innen der 10. Jahrgangsstufe teil. Der Vergleich der Mittelwerte des aufgabenbezogenen situationalen Interesses erbringt jedoch nur bei hoch an Geschichte interessierten Schüler/inne/n Unterschiede; bei ihnen fördert eine ästhetische Aufwertung des Arbeitsmaterials das situationale Interesse. Signifikant positive Korrelationen zwischen Fachinteresse und situationalem Interesse lassen sich sowohl auf Gesamtebene als auch auf Aufgabenebene feststellen.
Bei diesem Text handelt es sich um das Manuskript einer Hörfunk-Marginalie, die, vom Verfasser selbst gesprochen, am 10. Juni 1997 im Programm Bayern 2 des Bayerischen Rundfunks („Nachtstudio“) ausgestrahlt wurde. Der Verfasser hatte von 1995-2012 den Lehrstuhl für Didaktik der Geschichte der Ludwig-Maximilians Universität München inne.
Einführung in das Themenheft
(2014)
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.
Quantum computing is an emerging technology that has the potential to change the perspectives and applications of computing in general. A wide range of applications are enabled: from faster algorithmic solutions of classically still difficult problems to theoretically more secure communication protocols. A quantum computer uses the quantum mechanical effects of particles or particle-like systems, and a major similarity between quantum and classical computers consists of both being abstracted as information processing machines. Whereas a classical computer operates on classical digital information, the quantum computer processes quantum information, which shares similarities with analog signals. One of the central differences between the two types of information is that classical information is more fault-tolerant when compared to its quantum counterpart.
Faults are the result of the quantum systems being interfered by external noise, but during the last decades quantum error correction codes (QECC) were proposed as methods to reduce the effect of noise. Reliable quantum circuits are the result of designing circuits that operate directly on encoded quantum information, but the circuit’s reliability is also increased by supplemental redundancies, such as sub-circuit repetitions.
Reliable quantum circuits have not been widely used, and one of the major obstacles is their vast associated resource overhead, but recent quantum computing architectures show promising scalabilities. Consequently the number of particles used for computing can be more easily increased, and that the classical control hardware (inherent for quantum computation) is also more reliable. Reliable quantum circuits haev been investigated for almost as long as general quantum computing, but their limited adoption (until recently) has not generated enough interest into their systematic design.
The continuously increasing practical relevance of reliability motivates the present thesis to investigate some of the first answers to questions related to the background and the methods forming a reliable quantum circuit design stack.
The specifics of quantum circuits are analysed from two perspectives: their probabilistic behaviour and their topological properties when a particular class of QECCs are used. The quantum phenomena, such as entanglement and superposition, are the computational resources used for designing quantum circuits. The discrete nature of classical information is missing for quantum information. An arbitrary quantum system can be in an infinite number of states, which are linear combinations of an exponential number of basis states. Any nontrivial linear combination of more than one basis states is called a state superposition. The effect of superpositions becomes evident when the state of the system is inferred (measured), as measurements are probabilistic with respect to their output: a nontrivial state superposition will collapse to one of the component basis states, and the measurement result is known exactly only after the measurement.
A quantum system is, in general, composed from identical subsystems, meaning that a quantum computer (the complete system) operates on multiple similar particles (subsystems). Entanglement expresses the impossibility of separating the state of the subsystems from the state of the complete system: the nontrivial interactions between the subsystems result into a single indivisible state. Entanglement is an additional source of probabilistic behaviour: by measuring the state of a subsystem, the states of the unmeasured subsystems will probabilistically collapse to states from a well defined set of possible states. Superposition and entanglement are the building blocks of quantum information teleportation protocols, which in turn are used in state-of-the-art fault-tolerant quantum computing architectures. Information teleportation implies that the state of a subsystem is moved to a second subsystem without copying any information during the process.
The probabilistic approach towards the design of quantum circuits is initiated by the extension of classical test and diagnosis methods. Quantum circuits are modelled similarly to classical circuits by defining gate-lists, and missing quantum gates are modelled by the single missing gate fault. The probabilistic approaches towards quantum circuits are facilitated by comparing these to stochastic circuits, which are a particular type of classical digital circuits. Stochastic circuits can be considered an emulation of analogue computing using digital components.
A first proposed design method, based on the direct comparison, is the simulation of quantum circuits using stochastic circuits by mapping each quantum gate to a stochastic computing sub-circuit. The resulting stochastic circuit is compiled and simulated on FPGAs. The obtained results are encouraging and illustrate the capabilities of the proposed simulation technique. However, the exponential number of possible quantum basis states was translated into an exponential number of stochastic computing elements.
A second contribution of the thesis is the proposal of test and diagnosis methods for both stochastic and quantum circuits. Existing verification (tomographic) methods of quantum circuits were targeting the reconstruction of the gate-lists. The repeated execution of the quantum circuit was followed by different but specific measurement at the circuit outputs. The similarities between stochastic and quantum circuits motivated the proposal of test and diagnosis methods that use a restricted set of measurement types, which minimise the number of circuit executions. The obtained simulation results show that the proposed validation methods improve the feasibility of quantum circuit tomography for small and medium size circuits.
A third contribution of the thesis is the algorithmic formalisation of a problem encountered in teleportation-based quantum computing architectures. The teleportation results are probabilistic and require corrections represented as quantum gates from a particular set. However, there are known commutation properties of these gates with the gates used in the circuit. The corrections are not applied as dynamic gate insertions (during the circuit’s execution) into the gate-lists, but their effect is tracked through the circuit, and the corrections are applied only at circuit outputs. The simulation results show that the algorithmic solution is applicable for very large quantum circuits.
Topological quantum computing (TQC) is based on a class of fault-tolerant quantum circuits that use the surface code as the underlying QECC. Quantum information is encoded in lattice-like structures and error protection is enabled by the topological properties of the lattice. The 3D structure of the lattice allows TQC computations to be visualised similarly to knot diagrams. Logical information is abstracted as strands and strand interactions (braids) represent logical quantum gates. Therefore, TQC circuits are abstracted using a geometrical description, which allows circuit input-output transformations (correlations) to be represented as geometric sub-structures.
TQC design methods were not investigated prior to this work, and the thesis introduces the topological computational model by first analysing the necessary concepts. The proposed TQC design stack follows a top-down approach: an arbitrary quantum circuit is decomposed into the TQC supported gate set; the resulting circuit is mapped to a lattice of appropriate dimensions; relevant resulting topological properties are extracted and expressed using graphs and Boolean formulas. Both circuit representations are novel and applicable to TQC circuit synthesis and validation. Moreover, the Boolean formalism is broadened into a formal mechanism for proving circuit correctness.
The thesis introduces TQC circuit synthesis, which is based on a novel logical gate geometric description, whose formal correctness is demonstrated. Two synthesis methods are designed, and both use a general planar representation of the circuit. Initial simulation results demonstrate the practicality and performance of the methods.
An additional group of proposed design methods solves the problem of automatic correlation construction. The methods use validity criteria which were introduced and analysed beforehand in the thesis. Input-output correlations existing in the circuit are inferred using both the graph and the Boolean representation.
The thesis extends the TQC state-of-the-art by recognising the importance of correlations in the validation process: correlation construction is used as a sub-routine for TQC circuit validation. The presented cross-layer validation procedure is useful when investigating both the QECC and the circuit, while a second proposed method is QECC-independent. Both methods are scalable and applicable even to very large circuits.
The thesis completes with the analysis of TQC circuit identities, where the developed Boolean formalism is used. The proofs of former known circuit identities were either missing or complex, and the presented approach reduces the length of the proofs and represents a first step towards standardising them. A new identity is developed and detailed during the process of illustrating the known circuit identities.
Reliable quantum circuits are a necessity for quantum computing to become reality, and specialised design methods are required to support the quest for scalable quantum computers. This thesis used a twofold approach towards this target: firstly by focusing on the probabilistic behaviour of quantum circuits, and secondly by considering the requirements of a promising quantum computing architecture, namely TQC. Both approaches resulted in a set of design methods enabling the investigation of reliable quantum circuits.
The thesis contributes with the proposal of a new quantum simulation technique, novel and practical test and diagnosis methods for general quantum circuits, the proposal of the TQC design stack and the set of design methods that form the stack. The mapping, synthesis and validation of TQC circuits were developed and evaluated based on a novel and promising formalism that enabled checking circuit correctness.
Future work will focus on improving the understanding of TQC circuit identities as it is hoped that these are the key for circuit compaction and optimisation. Improvements to the stochastic circuit simulation technique have the potential of spawning new insights about quantum circuits in general.
Vom 21. Juni 2013 bis zum 23. Juni 2013 fand an der Universität Passau das Symposium „Gender.Frauen.Wissenschaft.“ statt, auf dem der vorliegende Sammelband basiert. Veranstalterin war das Frauenbüro der Universität Passau, welches mit der Veranstaltung verschiedene Ziele bezweckte. Ausgehend von der Tatsache, dass es an der Universität zu dem Zeitpunkt keine institutionalisierten Gender-Studies gab, aber viele Wissenschaftlerinnen und Wissenschaftler, die zu Genderfragen bzw. Genderaspekten in ihrem Fach forschen, sollte das Symposium solchen Personen die Gelegenheit geben, sich kennenzulernen, über die Forschungsprojekte sich auszutauschen und zu vernetzen. In der Tat glückte der intra- und interfakultäre Ansatz. Da sich das Symposium als Förderinstrument verstand, sollte der Schwerpunkt auf dem wissenschaftlichen Nachwuchs liegen. So versammelt der Band Beiträge von Autorinnen und Autoren in ganz unterschiedlichen Qualifizierungsphasen.
This thesis addresses a problem related to usage analysis in information retrieval
systems. Indeed, we exploit the history of search queries as support of analysis to
extract a profile model. The objective is to characterize the user and the data source
that interact in a system to allow different types of comparison (user-to-user, sourceto-
source, user-to-source). According to the study we conducted on the work done on
profile model, we concluded that the large majority of the contributions are strongly
related to the applications within they are proposed. As a result, the proposed
profile models are not reusable and suffer from several weaknesses. For instance,
these models do not consider the data source, they lack of semantic mechanisms and
they do not deal with scalability (in terms of complexity). Therefore, we propose
a generic model of user and data source profiles. The characteristics of this model
are the following. First, it is generic, being able to represent both the user and the
data source. Second, it enables to construct the profiles in an implicit way based on histories of search queries. Third, it defines the profile as a set of topics of interest,
each topic corresponding to a semantic cluster of keywords extracted by a specific
clustering algorithm. Finally, the profile is represented according to the vector space
model. The model is composed of several components organized in the form of a
framework, in which we assessed the complexity of each component.
The main components of the framework are:
• a method for keyword queries disambiguation
• a method for semantically representing search query logs in the form of a
taxonomy;
• a clustering algorithm that allows fast and efficient identification of topics of
interest as semantic clusters of keywords;
• a method to identify user and data source profiles according to the generic
model.
This framework enables in particular to perform various tasks related to usage-based
structuration of a distributed environment. As an example of application, the framework
is used to the discovery of user communities, and the categorization of data
sources. To validate the proposed framework, we conduct a series of experiments
on real logs from the search engine AOL search, which demonstrate the efficiency
of the disambiguation method in short queries, and show the relation between the
quality based clustering and the structure based clustering.