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Physically-based distributed rainfall-runoff models as the standard analysis tools for hydro-logical processes have been used to simulate the water system in detail, which includes spa-tial patterns and temporal dynamics of hydrological variables and processes (Davison et al., 2015; Ek and Holtslag, 2004). In general, catchment models are parameterized with spatial information on soil, vegetation and topography. However, traditional approaches for eval-uation of the hydrological model performance are usually motivated with respect to dis-charge data alone. This may thus cloud model realism and hamper understanding of the catchment behavior. It is necessary to evaluate the model performance with respect to in-ternal hydrological processes within the catchment area as well as other components of wa-ter balance rather than runoff discharge at the catchment outlet only. In particular, a consid-erable amount of dynamics in a catchment occurs in the processes related to interactions of the water, soil and vegetation. Evapotranspiration process, for instance, is one of those key interactive elements, and the parameterization of soil and vegetation in water balance mod-eling strongly influences the simulation of evapotranspiration. Specifically, to parameterize the water flow in unsaturated soil zone, the functional relationships that describe the soil water retention and hydraulic conductivity characteristics are important. To define these functional relationships, Pedo-Transfer Functions (PTFs) are common to use in hydrologi-cal modeling. Opting the appropriate PTFs for the region under investigation is a crucial task in estimating the soil hydraulic parameters, but this choice in a hydrological model is often made arbitrary and without evaluating the spatial and temporal patterns of evapotran-spiration, soil moisture, and distribution and intensity of runoff processes. This may ulti-mately lead to implausible modeling results and possibly to incorrect decisions in regional water management. Therefore, the use of reliable evaluation approaches is continually re-quired to analyze the dynamics of the current interactive hydrological processes and predict the future changes in the water cycle, which eventually contributes to sustainable environ-mental planning and decisions in water management.
Remarkable endeavors have been made in development of modelling tools that provide insights into the current and future of hydrological patterns in different scales and their im-pacts on the water resources and climate changes (Doell et al., 2014; Wood et al., 2011). Although, there is a need to consider a proper balance between parameter identifiability and the model's ability to realistically represent the response of the natural system. Neverthe-less, tackling this issue entails investigation of additional information, which usually has to be elaborately assembled, for instance, by mapping the dominant runoff generation pro-cesses in the intended area, or retrieving the spatial patterns of soil moisture and evapotran-spiration by using remote sensing methods, and evaluation at a scale commensurate with hydrological model (Koch et al., 2022; Zink et al., 2018). The present work therefore aims to give insights into the modeling approaches to simulate water balance and to improve the soil and vegetation parameterization scheme in the hydrological model subject to producing more reliable spatial and temporal patterns of evapotranspiration and runoff processes in the catchment.
An important contribution to the overall body of work is a book chapter included among publications. The book chapter provides a comprehensive overview of the topic and valua-ble insights into the understanding the water balance and its estimation methods.
Moreover, the first paper aimed to evaluate the hydrological model behavior with re-spect to contribution of various sources of information. To do so, a multi-criteria evaluation metric including soft and hard data was used to define constraints on outputs of the 1-D hydrological model WaSiM-ETH. Applying this evaluation metric, we could identify the optimal soil and vegetation parameter sets that resulted in a “behavioral” forest stand water balance model. It was found out that even if simulations of transpiration and soil water con-tent are consistent with measured data, but still the dominant runoff generation processes or total water balance might be wrongly calculated. Therefore, only using an evaluation scheme which looks over different sources of data and embraces an understanding of the local controls of water loss through soil and plant, allowed us to exclude the unrealistic modeling outputs. The results suggested that we may need to question the generally accept-ed soil parameterization procedures that apply default parameter sets.
The second paper attempts to tackle the pointed model evaluation hindrance by getting down to the small-scale catchment (in Bavaria). Here, a methodology was introduced to analyze the sensitivity of the catchment water balance model to the choice of the Pedo-Transfer Functions (PTF). By varying the underlying PTFs in a calibrated and validated model, we could determine the resulting effects on the spatial distribution of soil hydraulic properties, total water balance in catchment outlet, and the spatial and temporal variation of the runoff components. Results revealed that the water distribution in the hydrologic system significantly differs amongst various PTFs. Moreover, the simulations of water balance components showed high sensitivity to the spatial distribution of soil hydraulic properties. Therefore, it was suggested that opting the PTFs in hydrological modeling should be care-fully tested by looking over the spatio-temporal distribution of simulated evapotranspira-tion and runoff generation processes, whether they are reasonably represented.
To fulfill the previous studies’ suggestions, the third paper then aims to focus on evalu-ating the hydrological model through improving the spatial representation of dominant run-off processes. It was implemented in a mesoscale catchment in southwestern Germany us-ing the hydrological model WaSiM-ETH. Dealing with the issues of inadequate spatial ob-servations for rigorous spatial model evaluation, we made use of a reference soil hydrologic map available for the study area to discern the expected dominant runoff processes across a wide range of hydrological conditions. The model was parameterized by applying 11 PTFs and run by multiple synthetic rainfall events. To compare the simulated spatial patterns to the patterns derived by digital soil map, a multiple-component spatial performance metric (SPAEF) was applied. The simulated DRPs showed a large variability with regard to land use, topography, applied rainfall rates, and the different PTFs, which highly influence the rapid runoff generation under wet conditions.
The three published manuscripts proceeded towards the model evaluation viewpoints that ultimately attain the behavioral model outputs. It was performed through obtaining information about internal hydrological processes that lead to certain model behaviors, and also about the function and sensitivity of some of the soil and vegetation parameters that may primarily influence those internal processes in a catchment. Accordingly, using this understanding on model reactions, and by setting multiple evaluation criteria, it was possi-ble to identify which parameterization could lead to behavioral model realization. This work, in fact, will contribute to solving some of the issues (e.g., spatial variability and modeling methods) identified as the 23 unsolved problems in hydrology in the 21st century (Blöschl et al., 2019). The results obtained in the present work encourage the further inves-tigations toward a comprehensive model calibration procedure considering multiple data sources simultaneously. This will enable developing the new perspectives to the current parameter estimation methods, which in essence, focus on reproducing the plausible dy-namics (spatio-temporal) of the other hydrological processes within the watershed.
This thesis consists of four highly related chapters examining China’s rise in the aluminium industry. The first chapter addresses the conditions that allowed China, which first entered the market in the 1950s, to rise to world leadership in aluminium production. Although China was a latecomer, its re-entry into the market after the oil crises in the 1970s was a success and led to its ascent as the world’s largest aluminium producer by 2001. With an estimated production of 40.4 million tonnes in 2022, China represented almost 60% of the global output. Chapter 1 examines the factors underlying this success, such as the decline of international aluminium cartels, the introduction of innovative technology, the US granting China the MFN tariff status, Chinese-specific factors, and supportive government policies. Chapter 2 develops a mathematical model to analyze firms’ decisions in the short term. It examines how an incumbent with outdated technology and a new entrant with access to a new type of technology make strategic decisions, including the incumbent’s decision whether to deter entry, the production choice of firms, the optimal technology adoption rate of the newcomer, and cartel formation. Chapter 3 focuses on the adoption of new technology by firms upon market entry in four scenarios: firstly, a free market Cournot competition; secondly, a situation in which the government determines technology adoption rates; thirdly, a scenario in which the government controls both technology and production; and finally, a scenario where the government dictates technology adoption rates, production levels, and also the number of market participants. Chapter 4 applies the Spencer and Brander (1983) framework to examine strategic industrial policy. The model assumes that there are two exporting firms in two different countries that sell a product to a third country. We examine how the domestic firm is influenced by government intervention, such as the provision of a fixed-cost subsidy to improve its competitiveness relative to the foreign company. Chapter 4 initially investigates a scenario where only one government offers a fixed-cost subsidy, followed by an analysis of the case when both governments simultaneously provide financial help. Taken together, these chapters provide a comprehensive analysis of the strategic, technological, and political factors contributing to China’s leadership in the global aluminium industry.
Chapter 1: The Rise of China as a Latecomer in the Global Aluminium Industry
This chapter examines China’s remarkable transformation into a global leader in the aluminium industry, a sector in which the country accounted for approximately 58.9% of worldwide production in 2022. We examine how China, a latecomer to the aluminium industry that started off with labor-intensive technology in 1953, grew into the largest aluminium producer with some of the most advanced smelters in the world. This analysis identifies and discusses several opportunities that Chinese aluminium producers took advantage of. The first set of opportunities happened during the 1970s oil crises, which softened international competition and allowed China to acquire innovative smelting technology from Japan. The second set of opportunities started at about the same time when China opened its economy in 1978. The substantial demand for aluminium in China is influenced by both external and internal factors. Externally, the US granted China’s MFN tariff status in 1980 and China entered the World Trade Organization (WTO) in 2001. Both events contributed to a surge in Chinese aluminium consumption. Internally, China’s investment-led growth model boosted further its aluminium demand. Additional factors specific to China, such as low labor costs and the abundance of coal as an energy source, offer Chinese firms competitive advantages against international players. Furthermore, another window of opportunity is due to Chinese governmental policies, including phasing out old technology, providing subsidies, and gradually opening the economy to enhance domestic competition before expanding globally. By describing these elements, the study provides insights into the dynamic interplay of external circumstances and internal strategies that contributed to the success of the Chinese aluminium industry.
Chapter 2: Technological Change and Strategic Choices for Incumbent and New Entrant
This chapter introduces an oligopoly model that includes two actors: an incumbent and a potential entrant, that compete in the same market. We assume that two participants are located in different parts of the market: the incumbent is situated in area 1, whereas the potential entrant may venture into the other region, area 2. The incumbent exists in stage zero, where it can decide whether to deter the newcomer’s entry. A new type of technology exists in period one, when the newcomer may enter the market. In the short term, the incumbent is trapped with the outdated technology, while the new entrant may choose to partially or completely adopt the latest technology. Our results suggest the following: Firstly, the incumbent only tries to deter the new entrant if a condition for entry cost is met. Secondly, the new entrant is only interested in forming a cartel with the incumbent if a function of the ratio of the variable to new technology’s fixed-cost parameters is sufficiently high. Thirdly, if the newcomer asks to form a cartel, the incumbent will always accept this request. Finally, we can obtain the optimal new technology adoption rate for the newcomer.
Chapter 3: Technological Adoption and Welfare in Cournot Oligopoly
This study examines the difference between the optimal technology adoption rates chosen by firms in a homogeneous Cournot oligopoly and that preferred by a benevolent government upon firms’ market entry. To address the question of whether the technology choices of firms and government are similar, we analyze several different scenarios, which differ in the extent of government intervention in the market. Our results suggest a relationship between the number of firms in the market and the impact of government intervention on technology adoption rates. Especially in situations with a low number of firms that are interested in entering the market, greater government influence tends to lead to higher technology adoption rates of firms. Conversely, in scenarios with a higher number of firms and a government that lacks control over the number of market players, the technology adoption rate of firms will be highest when the government plays no role.
Chapter 4: International Technological Innovation and Industrial Strategies
Supporting domestic firms when they first enter the market may be seen as a favorable policy choice by governments around the world thanks to their ability to enhance the competitive advantage of domestic firms in non-cooperative competition against foreign enterprises (infant industry protection argument). This advantage may allow domestic firms to increase their market share and generate higher profits, thereby improving domestic welfare. This chapter utilizes the Spencer and Brander (1983) framework as a theoretical foundation to elucidate the effects of fixed-cost subsidies on firms’ production levels, technological innovations, and social welfare. The analysis examines two firms in different countries, each producing a homogeneous product that is sold in a third, separate country. We first examine the Cournot-Nash equilibrium in the absence of government intervention, followed by analyzing a scenario where just one government provides a financial subsidy for its domestic firm, and finally, we consider a situation where both governments simultaneously provide financial assistance for their respective firms. Our results suggest that governments aim to maximize social welfare by providing fixed-cost subsidies to their respective firms, finding themselves in a Chicken game scenario. Regarding technology innovation, subsidies lead to an increased technological adoption rate for recipient firms, regardless of whether one or both firms in a market receive support, compared to the situation without subsidies. The technology adoption rate of the recipient firm is higher than of its rival when only the recipient firm benefits from the fixed-cost subsidy. The lowest technology adoption rate of a firm occurs when the firm does not receive a fixed-cost subsidy, but its competitor does. Furthermore, global welfare will benefit the most in case when both exporting countries grant fixed-cost subsidies, and this welfare level is higher when only one country subsidizes than when no subsidies are provided by any country.
When humans encounter attitude objects (e.g., other people, objects, or constructs), they evaluate them. Often, these evaluations are based on attitudes. Whereas most research focuses on univalent (i.e., only positive or only negative) attitude formation, little research exists on ambivalent (i.e., simultaneously positive and negative) attitude formation. Following a general introduction into ambivalence, I present three original manuscripts investigating ambivalent attitude formation. The first manuscript addresses ambivalent attitude formation from previously univalent attitudes. The results indicate that responding to a univalent attitude object incongruently leads to ambivalence measured via mouse tracking but not ambivalence measured via self-report. The second manuscript addresses whether the same number of positive and negative statements presented block-wise in an impression formation task leads to ambivalence. The third manuscript also used an impression formation task and addresses the question of whether randomly presenting the same number of positive and negative statements leads to ambivalence. Additionally, the effect of block size of the same valent statements is investigated. The results of the last two manuscripts indicate that presenting all statements of one valence and then all statements of the opposite valence leads to ambivalence measured via self-report and mouse tracking. Finally, I discuss implications for attitude theory and research as well as future research directions.
Semantic-Aware Coordinated Multiple Views for the Interactive Analysis of Neural Activity Data
(2024)
Visualizing brain simulation data is in many aspects a challenging task. For one, data used in brain simulations and the resulting datasets is heterogeneous and insight is derived by relating all different kinds of it. Second, the analysis process is rapidly changing while creating hypotheses about the results. Third, the scale of data entities in these heterogeneous datasets is manifold, reaching from single neurons to brain areas interconnecting millions. Fourth, the heterogeneous data consists of a variety of modalities, e.g.: from time series data to connectivity data, from single parameters to a set of parameters spanning parameter spaces with multiple possible and biological meaningful solutions; from geometrical data to hierarchies and textual descriptions, all on mostly different scales. Fifth, visualizing includes finding suitable representations and providing real-time interaction while supporting varying analysis workflows. To this end, this thesis presents a scalable and flexible software architecture for visualizing, integrating and interacting with brain simulations data. The scalability and flexibility is achieved by interconnected services forming in a series of Coordinated Multiple View (CMV) systems. Multiple use cases are presented, introducing views leveraging this architecture, extending its ecosystem and resulting in a Problem Solving Environment (PSE) from which custom-tailored CMV systems can be build. The construction of such CMV system is assisted by semantic reasoning hence the term semantic-aware CMVs.
Der vorliegende Beitrag greift die öffentliche Diskussion um den rechtspolitischen Umgang mit Hass, Hetze und Antisemitismus auf, die insbesondere nach dem Terroranschlag der Hamas am 07.10.2023 an Intensität und Dringlichkeit zugenommen hat. Dabei beleuchtet er einerseits das Straf- und Zivilrecht, legt andererseits einen besonderen Fokus auf öffentlich-rechtliche Konstellationen. Auf jedem dieser Gebiete werden Schwächen und Potenziale des Rechts und der Rechtsprechung aufgezeigt, zugleich aber auch die Grenzen staatlicher Gewalt verdeutlicht. Denn letztlich handelt es sich um ein gesellschaftliches Problem, dem – trotz aller Notwendigkeit staatlichen Handelns – in erster Linie durch Information, und erst in zweiter Linie durch das Recht begegnet werden muss.
Anmerkung: Es handelt sich um die 2. überarbeitete Auflage der Dissertation.
1. Auflage siehe:
"https://ubt.opus.hbz-nrw.de/frontdoor/index/index/docId/2083".
Ausgangspunkt der politisch-ikonographischen Untersuchung, in deren
Zentrum zwei Staatsporträts König Maximilians II. von Bayern stehen, ist die Beobachtung, dass diese beiden Bildnisse grundsätzlich unterschiedliche Inszenierungsformen wählen. Das erste von Max Hailer gefertigte Werk zeigt Maximilian II. im vollen bayerischen Krönungsornat und greift eine tradierte Darstellungsweise im Staatsporträt auf. Es entstand zwei Jahre nach Maximilians II. Thronbesteigung und damit nach den revolutionären Unruhen der Jahre 1848/49 im Jahr 1850. Das zweite wurde von Joseph Bernhardt 1857 bis 1858 gemalt und im Jahr 1858 zum zehnjährigen Thronjubiläum des Monarchen erstmals präsentiert. Die Inszenierung ändert sich im zweiten Bildnis: Das bayerische Krönungsornat ist der Generalsuniform gewichen, ebenso weitere Details, die sich noch in der ersten Darstellung finden: Draperie und Wappen fehlen, der übliche bayerisch-königliche Thronsessel ist durch einen anderen ersetzt. In den Hintergrund gedrängt ist die Verfassung, immerhin seit 1818 staatliche Rechtsgrundlage des bayerischen Königreichs. Die beiden Staatsporträts Maximilians II. leiten offensichtlich von den Herrscherbildnissen im vollen bayerischen Krönungsornat seines Großvaters Maximilian I. und Vaters Ludwig I. über zu einer solchen in Uniform mit Krönungsmantel wie sie sich bei Napoleon III. und Friedrich Wilhelm IV. finden und wie sie sein Sohn Ludwig II. weiterführte. Es stellt sich somit die Frage, welche Faktoren zu diesem prägnanten Wandel in der Inszenierung Maximilians II. als König von Bayern führten. Die Arbeit geht der These nach, dass beide Darstellungen grundlegend auf eine reaktionäre, gegen die Revolution 1848/49 gerichtete Politik ausgelegt sind, wobei dieser reaktionäre Charakter in Maximilians II. Bildnis von 1858 noch eine Steigerung im Vergleich zu derjenigen von 1850 erfährt. Zudem wandelt sich die innenpolitisch-historische Ausrichtung des ersten Porträts bei der zweiten Darstellung des bayerischen Monarchen in eine außenpolitisch-progressive. Die Legitimation Maximilians II. begründet sich nicht mehr, wie bei ersterem, in der Geschichte und der Herrschaft der Wittelsbacher, sondern in seinen eigenen Errungenschaften und seiner eigenen Herrschaft. Dieser Wechsel der politischen Bildaussage fußt sowohl auf den politischen Veränderungen und Entwicklungen innerhalb und außerhalb Bayerns als auch auf der Entwicklung des Staatsporträts in der Mitte des 19. Jahrhunderts. Nach nur zehn Jahren wird so eine veränderte Botschaft über Maximilians II. Position und Machtanspruch ausgesendet.
Sowohl national als auch international wird die zunehmende Digitalisierung von Prozessen gefordert. Die Heterogenität und Komplexität der dabei entstehenden Systeme erschwert die Partizipation für reguläre Nutzergruppen, welche zum Beispiel kein Expertenwissen in der Programmierung oder einen informationstechnischen Hintergrund aufweisen. Als Beispiel seien hier Smart Contracts genannt, deren Programmierung komplex ist und bei denen etwaige Fehler unmittelbar mit monetärem Verlust durch die direkte Verknüpfung der darunterliegenden Kryptowährung verbunden sind. Die vorliegende Arbeit stellt ein alternatives Protokoll für cyber-physische Verträge vor, das sich besonders gut für die menschliche Interaktion eignet und auch von regulären Nutzergruppen verstanden werden kann. Hierbei liegt der Fokus auf der Transparenz der Übereinkünfte und es wird weder eine Blockchain noch eine darauf beruhende digitale Währung verwendet. Entsprechend kann das Vertragsmodell der Arbeit als nachvollziehbare Verknüpfung zwischen zwei Parteien verstanden werden, welches die unterschiedlichen Systeme sicher miteinander verbindet und so die Selbstorganisation fördert. Diese Verbindung kann entweder computergestützt automatisch ablaufen, oder auch manuell durchgeführt werden. Im Gegensatz zu Smart Contracts können somit Prozesse Stück für Stück digitalisiert werden. Die Übereinkünfte selbst können zur Kommunikation, aber auch für rechtlich bindende Verträge genutzt werden. Die Arbeit ordnet das neue Konzept in verwandte Strömungen wie Ricardian oder Smart Contracts ein und definiert Ziele für das Protokoll, welche in Form der Referenzimplementierung umgesetzt werden. Sowohl das Protokoll als auch die Implementierung werden im Detail beschrieben und durch eine Erweiterung der Anwendung ergänzt, welche es Nutzenden in Regionen ohne direkte Internetverbindung ermöglicht, an ebenjenen Verträgen teilnehmen zu können. Weiterhin betrachtet die Evaluation die rechtlichen Rahmenbedinungen, die Übertragung des Protokolls auf Smart Contracts und die Performanz der Implementierung.
This dissertation focusses on research into the personality construct of action vs. state orientation. Derived from the Personality-Systems-Interaction Theory (PSI Theory), state orientation is defined as a low ability to self-regulate emotions and associated with many adverse consequences – especially under stress. Because of the high prevalence of state orientation, it is a very important topic to investigate factors that help state-oriented people to buffer these adverse consequences. Action orientation, in contrast, is defined as a high ability to self-regulate own emotions in a very specific way: through accessing the self. The present dissertation demonstrates this theme in five studies, using a total of N = 1251 participants with a wide age range, encompassing different populations (students, non-student population (people from the coaching and therapy sector), applying different operationalisations to investigate self-access as a mediator or an outcome variable. Furthermore, it is tested whether the popular technique of mindfulness - that is advertised as a potent remedy for bringing people closer to the self -really works for everybody. The findings show that the presumed remedy is rather harmful for state-oriented individuals. Finally, an attempt to ameliorate these alienating effects, the present dissertation attempts to find theory-driven, and easy-to-apply solution how mindfulness exercises can be adapted.
Knowledge acquisition comprises various processes. Each of those has its dedicated research domain. Two examples are the relations between knowledge types and the influences of person-related variables. Furthermore, the transfer of knowledge is another crucial domain in educational research. I investigated these three processes through secondary analyses in this dissertation. Secondary analyses comply with the broadness of each field and yield the possibility of more general interpretations. The dissertation includes three meta-analyses: The first meta-analysis reports findings on the predictive relations between conceptual and procedural knowledge in mathematics in a cross-lagged panel model. The second meta-analysis focuses on the mediating effects of motivational constructs on the relationship between prior knowledge and knowledge after learning. The third meta-analysis deals with the effect of instructional methods in transfer interventions on knowledge transfer in school students. These three studies provide insights into the determinants and processes of knowledge acquisition and transfer. Knowledge types are interrelated; motivation mediates the relation between prior and later knowledge, and interventions influence knowledge transfer. The results are discussed by examining six key insights that build upon the three studies. Additionally, practical implications, as well as methodological and content-related ideas for further research, are provided.
Information in der vorvertraglichen Phase – das heißt, Informationspflichten sowie Rechtsfolgen von Informationserteilung und -nichterteilung – in Bezug auf Kaufvertrag und Wahl des optionalen Instruments hat im Vorschlag der Europäischen Kommission für ein Gemeinsames Europäisches Kaufrecht (GEK; KOM(2011) 635) vielfältige Regelungen erfahren. Die vorliegende Arbeit betrachtet diese Regelungen auch in ihrem Verhältnis zu den Textstufen des Europäischen Privatrechts – Modellregeln und verbraucherschützende EU-Richtlinien – und misst sie an ökonomischen Rahmenbedingungen, die die Effizienz von Transaktionen gebieten und Grenzen des Nutzens von (Pflicht-)Informationen aufzeigen.
Vom Grundsatz der Vertragsfreiheit ausgehend ist jeder Partei das Risiko zugewiesen, unzureichend informiert zu sein, während die Gegenseite nur punktuell zur Information verpflichtet ist. Zwischen Unternehmern bleibt es auch nach dem GEK hierbei, doch zwischen Unternehmer und Verbraucher wird dieses Verhältnis umgekehrt. Dort gelten, mit Differenzierung nach Vertragsschlusssituationen, umfassende Kataloge von Informationspflichten hinsichtlich des Kaufvertrags. Als Konzept ist dies grundsätzlich sinnvoll; die Pflichten dienen dem Verbraucherschutz, insbesondere der Informiertheit und Transparenz vor der Entscheidung über den Vertragsschluss. Teilweise gehen die Pflichten aber zu weit. Die Beeinträchtigung der Vertragsfreiheit des Unternehmers durch die Pflichten und die Folgen ihrer Verletzung lässt sich nicht vollständig mit dem Ziel des Verbraucherschutzes rechtfertigen. Durch das Übermaß an Information fördern die angeordneten Pflichten den Verbraucherschutz nur eingeschränkt; sie genügen nicht verhaltensökonomischen Maßstäben. Es empfiehlt sich daher, zwischen Unternehmern und Verbrauchern bestimmte verpflichtende Informationsinhalte ganz zu streichen, auf im konkreten Fall nicht erforderliche Information zu verzichten, erst nach Vertragsschluss relevante Informationen auf diese Zeit zu verschieben und die verbleibenden vorvertraglichen Pflichtinformationen in einer für den Verbraucher besser zu verarbeitenden Weise zu präsentieren. Von den einem Verbraucher zu erteilenden Informationen sollte stets verlangt werden, dass sie klar und verständlich sind; die Beweislast für ihre ordnungsgemäße Erteilung sollte generell dem Unternehmer obliegen.
Neben die ausdrücklich angeordneten Informationspflichten treten ungeachtet der Verbraucher- oder Unternehmereigenschaft sowie der Käufer- oder Verkäuferrolle stark einzelfallabhängige Informationspflichten nach Treu und Glauben, die im Recht der Willensmängel niedergelegt sind. Hier ist der Grundsatz verwirklicht, dass mangelnde Information zunächst das eigene Risiko jeder Partei ist; berechtigtes Vertrauen und freie Willensbildung werden geschützt. Diese Pflichten berücksichtigen auch das Ziel der Effizienz und achten die Vertragsfreiheit. Das Vertrauen auf jegliche erteilten Informationen wird zudem dadurch geschützt, dass sie den Vertragsinhalt – allerdings in Verbraucherverträgen nicht umfassend genug – mitbestimmen können und dass ihre Unrichtigkeit sanktioniert wird.
Die Verletzung jeglicher Arten von Informationspflichten kann insbesondere einen Schadensersatzanspruch sowie – über das Recht der Willensmängel – die Möglichkeit zur Lösung vom Vertrag nach sich ziehen. Das Zusammenspiel der unterschiedlichen Mechanismen führt allerdings zu Friktionen sowie zu Lücken in den Rechtsfolgen von Informationspflichtverletzungen. Daher empfiehlt sich die Schaffung eines Schadensersatzanspruchs für jede treuwidrig unterlassene Informationserteilung; hierdurch wird das Gebot von Treu und Glauben auch außerhalb des Rechts der Willensmängel zu einer eigentlichen einzelfallabhängigen Informationspflicht aufgewertet.
Today, almost every modern computing device is equipped with multicore processors capable of efficient concurrent and parallel execution of threads. This processor feature can be leveraged by concurrent programming, which is a challenge for software developers for two reasons: first, it introduces a paradigm shift that requires a new way of thinking. Second, it can lead to issues that are unique to concurrent programs due to the non-deterministic, interleaved execution of threads. Consequently, the debugging of concurrency and related performance issues is a rather difficult and often tedious task. Developers still lack on thread-aware programming tools that facilitate the understanding of concurrent programs. Ideally, these tools should be part of their daily working environment, which typically includes an Integrated Development Environment (IDE). In particular, the way source code is visually presented in traditional source-code editors does not convey much information on whether the source code is executed concurrently or in parallel in the first place.
With this dissertation, we pursue the main goal of facilitating and supporting the understanding and debugging of concurrent programs. To this end, we formulate and utilize a visualization paradigm that particularly includes the display of interactive glyph-based visualizations embedded in the source-code editor close to their corresponding artifacts (in-situ).
To facilitate the implementation of visualizations that comply with our paradigm as plugins for IDEs, we designed, implemented and evaluated a programming framework called CodeSparks. After presenting the design goals and the architecture of the framework, we demonstrate its versatility with a total of fourteen plugins realized by different developers using the CodeSparks framework (CodeSparks plugins). With focus group interviews, we empirically investigated how developers of the CodeSparks plugins experienced working with the framework. Based on the plugins, deliberate design decisions and the interview results, we discuss to what extent we achieved our design goals. We found that the framework is largely target programming-language independent and that it supports the development of plugins for a wide range of source-code-related tasks while hiding most of the details of the underlying plugin development API.
In addition, we applied our visualization paradigm to thread-related runtime data from concurrent programs to foster the awareness of source code being executed concurrently or in parallel. As a result, we developed and designed two in-situ thread visualizations, namely ThreadRadar and ThreadFork, with the latter building on the former. Both thread visualizations are based on a debugging approach, which combines statistical profiling, thread-aware runtime metrics, clustering of threads on the basis of these metrics, and finally interactive glyph-based in-situ visualizations. To address scalability issues of the ThreadRadar in terms of space required and the number of displayable thread clusters, we designed a revised thread visualization. This revision also involved the question of how many thread clusters k should be computed in the first place. To this end, we conducted experiments with the clustering of threads for artifacts from a corpus of concurrent Java programs that include real-world Java applications and concurrency bugs. We found that the maximum k on the one hand and the optimal k according to four cluster validation indices on the other hand rarely exceed three. However, occasionally thread clusterings with k > 3 are available and also optimal. Consequently, we revised both the clustering strategy and the visualization as parts of our debugging approach, which resulted in the ThreadFork visualization. Both in-situ thread visualizations, including their additional features that support the exploration of the thread data, are implemented in a tool called CodeSparks-JPT, i.e., as a CodeSparks plugin for IntelliJ IDEA.
With various empirical studies, including anecdotal usage scenarios, a usability test, web surveys, hands-on sessions, questionnaires and interviews, we investigated quality aspects of the in-situ thread visualizations and their corresponding tools. First, by a demonstration study, we illustrated the usefulness of the ThreadRadar visualization in investigating and fixing concurrency bugs and a performance bug. This was confirmed by a subsequent usability test and interview, which also provided formative feedback. Second, we investigated the interpretability and readability of the ThreadFork glyphs as well as the effectiveness of the ThreadFork visualization through anonymous web surveys. While we have found that the ThreadFork glyphs are correctly interpreted and readable, it remains unproven that the ThreadFork visualization effectively facilitates understanding the dynamic behavior of threads that concurrently executed portions of source code. Moreover, the overall usability of CodeSparks-JPT is perceived as "OK, but not acceptable" as the tool has issues with its learnability and memorability. However, all other usability aspects of CodeSparks-JPT that were examined are perceived as "above average" or "good".
Our work supports software-engineering researchers and practitioners in flexibly and swiftly developing novel glyph-based visualizations that are embedded in the source-code editor. Moreover, we provide in-situ thread visualizations that foster the awareness of source code being executed concurrently or in parallel. These in-situ thread visualizations can, for instance, be adapted, extended and used to analyze other use cases or to replicate the results. Through empirical studies, we have gradually shaped the design of the in-situ thread visualizations through data-driven decisions, and evaluated several quality aspects of the in-situ thread visualizations and the corresponding tools for their utility in understanding and debugging concurrent programs.