Many systems exhibit rule-based behavior that can be modeled very well by means of graph transformation. In this thesis, a new graph transformation theory is introduced for a more expressive kind of graph transformation than the usual one. This kind of graph transformation not only allows positive pre- and post-conditions to be expressed in rules, but also allows so-called negative application conditions. Present analysis techniques are extended for this more expressive kind of graph transformation. These techniques allow, amongst other things, the static detection of potential conflicts and causal dependencies between transformations, and the detection of local confluence in cases of conflicts. For this purpose, the theory of critical pairs is extended. Moreover, new kinds of analysis techniques are introduced and present techniques are improved. One new technique enables, for example, the static analysis of applicability (resp. non-applicability) of rule sequences. The main part of the newly developed theory in this thesis does not only apply to graph transformation. In addition, it is formulated in the more abstract adhesive high-level-transformation framework. Consequently, the analysis techniques can be applied not only to graphs, but also to other complex structures such as, for example, Petri nets and attributed graphs. Finally, a general road map is presented leading to the certification of a selection of properties in rule-based models. The certification, based on graph transformation analysis techniques, is illustrated by a case study of an elevator control system. Moreover, the current tool support for certification of rule-based models using graph transformation provided by AGG is outlined.

Geospatial data has become a natural part of a growing number of information systems and services in the economy, society, and people's personal lives. In particular, virtual 3D city and landscape models constitute valuable information sources within a wide variety of applications such as urban planning, navigation, tourist information, and disaster management. Today, these models are often visualized in detail to provide realistic imagery. However, a photorealistic rendering does not automatically lead to high image quality, with respect to an effective information transfer, which requires important or prioritized information to be interactively highlighted in a context-dependent manner. Approaches in non-photorealistic renderings particularly consider a user's task and camera perspective when attempting optimal expression, recognition, and communication of important or prioritized information. However, the design and implementation of non-photorealistic rendering techniques for 3D geospatial data pose a number of challenges, especially when inherently complex geometry, appearance, and thematic data must be processed interactively. Hence, a promising technical foundation is established by the programmable and parallel computing architecture of graphics processing units. This thesis proposes non-photorealistic rendering techniques that enable both the computation and selection of the abstraction level of 3D geospatial model contents according to user interaction and dynamically changing thematic information. To achieve this goal, the techniques integrate with hardware-accelerated rendering pipelines using shader technologies of graphics processing units for real-time image synthesis. The techniques employ principles of artistic rendering, cartographic generalization, and 3D semiotics—unlike photorealistic rendering—to synthesize illustrative renditions of geospatial feature type entities such as water surfaces, buildings, and infrastructure networks. In addition, this thesis contributes a generic system that enables to integrate different graphic styles—photorealistic and non-photorealistic—and provide their seamless transition according to user tasks, camera view, and image resolution. Evaluations of the proposed techniques have demonstrated their significance to the field of geospatial information visualization including topics such as spatial perception, cognition, and mapping. In addition, the applications in illustrative and focus+context visualization have reflected their potential impact on optimizing the information transfer regarding factors such as cognitive load, integration of non-realistic information, visualization of uncertainty, and visualization on small displays.

Database systems have been vital in all forms of data processing for a long time. In recent years, the amount of processed data has been growing dramatically, even in small projects. Nevertheless, database management systems tend to be static in terms of size and performance which makes scaling a difficult and expensive task. Because of performance and especially cost advantages more and more installed systems have a shared nothing cluster architecture. Due to the massive parallelism of the hardware programming paradigms from high performance computing are translated into data processing. Database research struggles to keep up with this trend. A key feature of traditional database systems is to provide transparent access to the stored data. This introduces data dependencies and increases system complexity and inter process communication. Therefore, many developers are exchanging this feature for a better scalability. However, explicitly managing the data distribution and data flow requires a deep understanding of the distributed system and reduces the possibilities for automatic and autonomic optimization. In this thesis we present an approach for database system scaling and allocation that features good scalability although it keeps the data distribution transparent. The first part of this thesis analyzes the challenges and opportunities for self-scaling database management systems in cluster environments. Scalability is a major concern of Internet based applications. Access peaks that overload the application are a financial risk. Therefore, systems are usually configured to be able to process peaks at any given moment. As a result, server systems often have a very low utilization. In distributed systems the efficiency can be increased by adapting the number of nodes to the current workload. We propose a processing model and an architecture that allows efficient self-scaling of cluster database systems. In the second part we consider different allocation approaches. To increase the efficiency we present a workload-aware, query-centric model. The approach is formalized; optimal and heuristic algorithms are presented. The algorithms optimize the data distribution for local query execution and balance the workload according to the query history. We present different query classification schemes for different forms of partitioning. The approach is evaluated for OLTP and OLAP style workloads. It is shown that variants of the approach scale well for both fields of application. The third part of the thesis considers benchmarks for large, adaptive systems. First, we present a data generator for cloud-sized applications. Due to its architecture the data generator can easily be extended and configured. A key feature is the high degree of parallelism that makes linear speedup for arbitrary numbers of nodes possible. To simulate systems with user interaction, we have analyzed a productive online e-learning management system. Based on our findings, we present a model for workload generation that considers the temporal dependency of user interaction.

This thesis is about real-time rendering algorithms that can render 3D-geometry with quality and design features beyond standard display. Examples include algorithms to render shadows, reflections, or transparency. Integrating these algorithms into 3D-applications using today’s rendering libraries for real-time computer graphics is exceedingly difficult: On the one hand, the rendering algorithms are technically and algorithmically complicated for their own, on the other hand, combining several algorithms causes resource conflicts and side effects that are very diffi-cult to handle. Scene graph libraries, which intend to provide a software layer to abstract from computer graphics hardware, currently offer no mechanisms for using these rendering algo-rithms, either. The objective of this thesis is to design and to implement a software architecture for a scene graph library that models real-time rendering algorithms as software components allowing an effective usage of these algorithms for 3D-application development within the scene graph li-brary. An application developer using the scene graph library controls these components with elements in a scene description that describe the effect of a rendering algorithm for some geo-metry in the scene graph, but that do not contain hints about the actual implementation of the rendering algorithm. This allows for deploying rendering algorithms in 3D-applications even for application developers that do not have detailed knowledge about them. In this way, the com-plexity of development of rendering algorithms can be drastically reduced. In particular, the thesis focuses on the feasibility of combining several rendering algorithms within a scene at the same time. This requires to classify rendering algorithms into different categories, which are, each, evaluated using different approaches. In this way, components for different rendering algorithms can collaborate and adjust their usage of common graphics re-sources. The possibility of combining different rendering algorithms can be limited in several ways: The graphical result of the combination can be undefined, or fundamental technical restrictions can render it impossible to use two rendering algorithms at the same time. The software architecture described in this work is not able to remove these limitations, but it allows to combine a lot of different rendering algorithms that, until now, could not be combined due to the high complexi-ties of the required implementation. The capability of collaboration, however, depends on the kind of rendering algorithm: For instance, algorithms for rendering transparent geometry can be combined with other algorithms only with a complete redesign of the algorithm. Therefore, components in the scene graph library for displaying transparency can be combined with com-ponents for other rendering algorithms in a limited way only. The system developed in this work integrates and combines algorithms for displaying bump mapping, several variants of shadow and reflection algorithms, and image-based CSG algo-rithms. Hence, major rendering algorithms are available for the first time in a scene graph li-brary as components with high abstraction level. Despite the required additional indirections and abstraction layers, the system, in principle, allows for using and combining the rendering algorithms in real-time.

This thesis introduces a collection of new real-time rendering techniques and applications for focus+context visualization of interactive 3D geovirtual environments such as virtual 3D city and landscape models. These environments are generally characterized by a large number of objects and are of high complexity with respect to geometry and textures. For these reasons, their interactive 3D rendering represents a major challenge. Their 3D depiction implies a number of weaknesses such as occlusions, cluttered image contents, and partial screen-space usage. To overcome these limitations and, thus, to facilitate the effective communication of geo-information, principles of focus+context visualization can be used for the design of real-time 3D rendering techniques for 3D geovirtual environments (see Figure). In general, detailed views of a 3D geovirtual environment are combined seamlessly with abstracted views of the context within a single image. To perform the real-time image synthesis required for interactive visualization, dedicated parallel processors (GPUs) for rasterization of computer graphics primitives are used. For this purpose, the design and implementation of appropriate data structures and rendering pipelines are necessary. The contribution of this work comprises the following five real-time rendering methods: The rendering technique for 3D generalization lenses enables the combination of different 3D city geometries (e.g., generalized versions of a 3D city model) in an single image in real time. The method is based on a generalized and fragment-precise clipping approach, which uses a compressible, raster-based data structure. It enables the combination of detailed views in the focus area with the representation of abstracted variants in the context area. The rendering technique for the interactive visualization of dynamic raster data in 3D geovirtual environments facilitates the rendering of 2D surface lenses. It enables a flexible combination of different raster layers (e.g., aerial images or videos) using projective texturing for decoupling image and geometry data. Thus, various overlapping and nested 2D surface lenses of different contents can be visualized interactively. The interactive rendering technique for image-based deformation of 3D geovirtual environments enables the real-time image synthesis of non-planar projections, such as cylindrical and spherical projections, as well as multi-focal 3D fisheye-lenses and the combination of planar and non-planar projections. The rendering technique for view-dependent multi-perspective views of 3D geovirtual environments, based on the application of global deformations to the 3D scene geometry, can be used for synthesizing interactive panorama maps to combine detailed views close to the camera (focus) with abstract views in the background (context). This approach reduces occlusions, increases the usage the available screen space, and reduces the overload of image contents. The object-based and image-based rendering techniques for highlighting objects and focus areas inside and outside the view frustum facilitate preattentive perception. The concepts and implementations of interactive image synthesis for focus+context visualization and their selected applications enable a more effective communication of spatial information, and provide building blocks for design and development of new applications and systems in the field of 3D geovirtual environments.

Raumbezogene Informationen stehen im Mittelpunkt vieler kommerzieller und wissenschaftli-cher Anwendungsfelder, wie zum Beispiel dem Bereich der mobilen Kommunikation, des Transports und Verkehrs, der Energieversorgung, der Geographie oder der Kartographie. Die technischen Fortschritte in der Datenerfassung, wie zum Beispiel durch Satellitenbeobachtung oder Laser-Scanning, erlauben die Sammlung immer größerer Mengen an raumbezogenen Da-ten in zunehmend hoher Qualität und Geschwindigkeit. Um diese Flut an raumbezogenen Daten zu bewältigen und aus ihnen Informationen zu gewin-nen bedarf es besonderer Verfahren und Strategien zur ihrer Verarbeitung und Visualisierung. Mit Visualisierung wird versucht, Einsicht in Daten, in ihre Struktur und in ihre Zusammenhän-ge zu erhalten. Hierbei dient Visualisierung als Instrument zur Präsentation, Exploration und Analyse von meist hochdimensionalen Datenräumen. Die computergestützte Visualisierung zieht in besonderem Maße von dem rapiden technischen Fortschritt der Computergraphik-Hardware Nutzen. Jedoch müssen für einzelne Anwendungs-felder, wie z. B. der Geovisualisierung, Verfahren, Werkzeuge und Systeme entwickelt werden, die den spezifischen Merkmalen des jeweiligen Gebiets Rechnung tragen, um dieses Potential voll auszuschöpfen. Als adäquate Medien zur Kommunikation räumlicher Informationen dienen seit Jahrhunderten kartographische Darstellungen, allen voran die Karte. Sie hat sich in den vergangenen Jahren vom statischen Medium hin zum interaktiven, dynamischen Medium entwickelt, ebenfalls durch den rasanten technischen Fortschritt, wie z. B. im Bereich der Geoinformationssysteme. Durch die Möglichkeit Informationsdichten und Darstellungsformen dynamisch an die jeweiligen Nut-zergruppen und Aufgabenanforderungen anzupassen, ergeben sich neue Formen der Kommuni-kation raumbezogener Information. Häufig werden dabei virtuelle, dreidimensionale Umgebun-gen zur Darstellung räumlicher Information genutzt, die in vielen Anwendungsfällen dem Men-schen vertrauter sind als orthographisch zweidimensionale Darstellungen, weil sie der natürli-chen Sehgewohnheit des Menschen näher kommen und bezüglich Raum und Zeit größere Frei-heitsgrade aufweisen. In dieser Arbeit werden Konzepte für 3D-Karten sowie Entwurf und Implementierung eines 3D-Kartensystems vorgestellt. 3D-Karten repräsentieren ein interaktives, dynamisches Medium zur Kommunikation raumbezogener Information, das auf interaktive dreidimensionaler Visualisie-rung beruht. Konkret beschreibt diese Arbeit das zugrundeliegende Softwaresystem, ausgewähl-te Visualisierungsstrategien und -verfahren sowie ausgewählte Anwendungsbeispiele für 3D-Karten.

Im Allgemeinen liegen Geodaten und georeferenzierte Daten verteilt vor, sind heterogen in ihrem Inhalt und ihrer Form, umfassen sehr große Datenmengen und müssen in verschiedenen IT-Informationssystemen integriert und in verschiedenen Anwendungskontexten genutzt werden. Im Mittelpunkt dieser Arbeit stehen deshalb Konzepte und Techniken für die Integration, Visualisierung, Analyse, Bereitstellung und Nutzung von 2D- und 3D-Geodaten sowie georeferenzierten Daten. Hierbei wird ein Ansatz verfolgt, der zum einen virtuelle 3D-Umgebungen als konzeptionellen und technischen Rahmen nutzt und zum anderen auf serviceorientierten Softwarearchitekturen und Geo-Standards basiert. Die vorgestellten Konzepte und Verfahren stellen damit Schlüsselbausteine dar, um neuartige IT-Lösungen und Anwendungen für 3D-Geoinformationen, z.B. als Bestandteile von Geodateninfrastrukturen, zu realisieren. Im Bereich der servicebasierten 3DGeovisualisierung beschreibt diese Arbeit, wie virtuelle 3D-Stadtmodelle für die Integration heterogener und verteilter Geodatenquellen genutzt werden können. Dazu werden Anforderungen für die Integration identifiziert und ein Konzept für die Integration auf Datenebene und die Integration auf Visualisierungsebene entworfen und deren Umsetzung am Beispiel komplexer 3D-Bauwerksinformationsmodelle beschrieben und demonstriert. Im Bereich servicebasierter, bildbasierter 3DPortrayal-Services wird mit dem Web View Service (WVS) ein spezialisierter SoftwareService für die Visualisierung, Interaktion und Analyse von geovirtuellen 3D-Umgebungen konzipiert und entwickelt. Kernkonzept dieses Services sind die serverseitige Datenintegration und -verwaltung sowie die ebenfalls serverseitige Bilderzeugung. Mit diesem durchgehend serverseitigen Ansatz können sehr große Mengen an 3D-Geodaten auch auf solchen Endgeräte bereitgestellt werden, die nicht über ausreichend Speicher und Rechenleistung für die Vorhaltung, die Verarbeitung und das Rendering von 3D-Modellen verfügen. Der entwickelte WVS ermöglicht so u.a. auch auf Tablet-PCs und im Webbrowser die interaktive Erkundung und Analyse von 3D-Geodaten. Anhand einer Referenzimplementierung des WVS und einer Client-Anwendung wird die praktische Anwendung des WVS demonstriert. Im Bereich der Komposition von Web View Services wird untersucht, wie der WVS als Baustein einer komplexen, verteilten Visualisierungs- und Renderingpipeline eingesetzt werden kann. Durch die Komposition des WVS mit anderen Darstellungs- und Verarbeitungsservices können z. B. komplexe Renderingeffekte erzielt oder einzelne 3D-Objekte nachträglich in eine 3D-Ansicht integriert werden. Hierzu wird ein Konzept zur servicebasierten, Tiefenbildbasierten Bildkomposition beschrieben und am Beispiel der verdeckungsfreien Annotation von 3D-Ansichten umgesetzt und demonstriert. Im Bereich der Interaktion mit Web View Services liefert diese Arbeit Grundlagen, Konzept und Umsetzung für intelligente, assistierende und automatisierte Interaktions- und Navigationstechniken, die auf dem Angebotscharakter (der Affordanz) von 3D-Szenenobjekten sowie auf der skizzen- und gestenbasierten Eingabe von Nutzerintentionen basiert. Diese Eingaben werden hinsichtlich ihrer Form und unter Berücksichtigung der Semantik der 3DSzenenobjekte ausgewertet und interpretiert und anschließend in anwendungsspezifische Navigationskommandos übersetzt, aus denen teilautomatische Kamerafahrten abgeleitet werden.

Drawings of graphs are often used to represent a given data set in a human-readable way. In this thesis, we consider different classic algorithmic problems that arise when automatically generating graph drawings. More specifically, we solve some open problems in the context of orthogonal drawings and advance the current state of research on the problems clustered planarity and simultaneous planarity.

For large distributed systems, the initial design of a stable software architecture has been identified as essential. Software architectures often emphasize behavior to ensure a suitable coarse-grain design, whilst the notations for object-oriented design concentrate on structural fine-grain domain models. Accordingly, integration of both strategies in the form of object-oriented design and architecture of distributed systems promises to enable a systematic development process that can cope with the inherent complexity of distributed systems. The presented Object Coordination Net (OCoN) approach provides such an integration by extending the UML with a set of behavioral views. Such can be applied in the exploration of design alternatives for distributed systems at an architectural level. The behavioral contract notion is one of the main concepts of the OCoN approach. An efficiently manageable behavioral subtyping notion is developed which supports even the design of open systems, not only can it express reactive but also autonomous forms of behavior. These contracts abstract from realization details and therefore improve design and modularity. The OCoN formalism that permits mixed event- and state-based true concurrent modeling is presented in this thesis. It will be demonstrated how such can be applied to describe contracts, object scheduling, resource handling and the abstract data and control flow of services. The seamless integration of contract specifications into service and object scheduling specifications is also demonstrated. Although abstract, the OCoN formalism remains operational which permits early evaluation via abstract simulation and guarantees a feasible implementation. % The presented contract notion supports open system design by dynamic type matching for independently evolved type systems based upon a behavioral protocol, compound types and structural subtyping. A formal semantics of the language that integrates typing and concurrent behavior is also presented.

This thesis addresses real-time non-photorealistic rendering techniques and their applications in interactive visualization. Real-time rendering has emerged as an important discipline within computer graphics developing a broad variety of rendering and optimization techniques along with dramatic advances in computer graphics hardware. While many applications of real-time rendering techniques concentrate on achieving photorealistic imagery, non-photorealistic computer graphics is investigating concepts and techniques that deliberately abstract from reality using expressive, stylized, or illustrative rendering, major goals include visual clarity, attractiveness, comprehensibility, and perceptibility in depictions. Non-photorealistic rendering techniques often rely on the concepts and principles found in traditional illustrations, graphics design, and art. The contributions of this thesis include three general-purpose real-time non-photorealistic rendering techniques: The edge-enhancement rendering technique accentuates visually important edges of 3D models facilitating the effective communication of their shape. The technique takes an image-space approach for edge detection and encodes the resulting edge intensities as texture, called edge map, to enhance 3D models on a per-object basis. The blueprint rendering technique extends the edge-enhancement technique to the 3D models’ occluded parts to accentuate their visible as well as their occluded visually important edges. Vivid and expressive depictions of complex aggregate objects become possible that facilitate the visual perception of spatial relationships and let viewers obtain insights into the models. The sketchy drawing rendering technique stylizes visually important edges of 3D models. Depicting 3D models in a sketchy manner allows us to express vagueness and is vitally important for communicating ideas and for presenting a preliminary, incomplete state. Two applications based on these real-time non-photorealistic rendering techniques in the fields of visualization demonstrate their ability to build compelling, interactive visual interfaces: Illustrative 3D city models apply non-photorealism to represent virtual spatial 3D environments together with associated thematic information. The abstracted, stylized depiction emphasizes components of 3D city models and thereby eases recognition, facilitates navigation, exploration, and analysis of spatial information. Illustrative CSG models apply non-photorealism to image-based CSG rendering. They enable us to visualize the design and assembly of complex CSG models in a comprehensible fashion. It also simplifies the interactive construction of CSG models. Finally, the thesis investigates an automated approach to depict dynamics as a complementary, important dimension in information contents by means of non-photorealistic rendering: The smart depiction system automatically generates compelling images of a 3D scene’s related dynamics following the traditional design principles found in comic books and storyboards. The system symbolizes past, ongoing, and future activities and events taking place in and related to 3D scenes. The non-photorealistic rendering techniques and exemplary applications presented in this thesis demonstrate that non-photorealistic rendering serves as a fundamental technology for expressive and effective visual communication and facilitates the implementation of user interfaces based on illustrating 3D scenes and their related dynamics in an informative and comprehensible way.

An increasing number of applications requires user interfaces that facilitate the handling of large geodata sets. Using virtual 3D city models, complex geospatial information can be communicated visually in an intuitive way. Therefore, real-time visualization of virtual 3D city models represents a key functionality for interactive exploration, presentation, analysis, and manipulation of geospatial data. This thesis concentrates on the development and implementation of concepts and techniques for real-time city model visualization. It discusses rendering algorithms as well as complementary modeling concepts and interaction techniques. Particularly, the work introduces a new real-time rendering technique to handle city models of high complexity concerning texture size and number of textures. Such models are difficult to handle by current technology, primarily due to two problems: 1) Limited texture memory: The amount of simultaneously usable texture data is limited by the memory of the graphics hardware. 2) Limited number of textures: Using several thousand different textures simultaneously causes significant performance problems due to texture switch operations during rendering. The multiresolution texture atlases approach, introduced in this thesis, overcomes both problems. During rendering, it permanently maintains a small set of textures that are sufficient for the current view and the screen resolution available. The efficiency of multiresolution texture atlases is evaluated in performance tests. To summarize, the results demonstrate that the following goals have been achieved: a) Real-time rendering becomes possible for 3D scenes whose amount of texture data exceeds the main memory capacity. b) Overhead due to texture switches is kept permanently low, so that the number of different textures has no significant effect on the rendering frame rate. Furthermore, this thesis introduces two new approaches for real-time city model visualization that use textures as core visualization elements: 1) An approach for visualization of thematic information. 2) An approach for illustrative visualization of 3D city models. Both techniques demonstrate that multiresolution texture atlases provide a basic functionality for the development of new applications and systems in the domain of city model visualization.

Massive Open Online Courses (MOOCs) open up new opportunities to learn a wide variety of skills online and are thus well suited for individual education, especially where proffcient teachers are not available locally. At the same time, modern society is undergoing a digital transformation, requiring the training of large numbers of current and future employees. Abstract thinking, logical reasoning, and the need to formulate instructions for computers are becoming increasingly relevant. A holistic way to train these skills is to learn how to program. Programming, in addition to being a mental discipline, is also considered a craft, and practical training is required to achieve mastery. In order to effectively convey programming skills in MOOCs, practical exercises are incorporated into the course curriculum to offer students the necessary hands-on experience to reach an in-depth understanding of the programming concepts presented. Our preliminary analysis showed that while being an integral and rewarding part of courses, practical exercises bear the risk of overburdening students who are struggling with conceptual misunderstandings and unknown syntax. In this thesis, we develop, implement, and evaluate different interventions with the aim to improve the learning experience, sustainability, and success of online programming courses. Data from four programming MOOCs, with a total of over 60,000 participants, are employed to determine criteria for practical programming exercises best suited for a given audience. Based on over five million executions and scoring runs from students' task submissions, we deduce exercise difficulties, students' patterns in approaching the exercises, and potential flaws in exercise descriptions as well as preparatory videos. The primary issue in online learning is that students face a social gap caused by their isolated physical situation. Each individual student usually learns alone in front of a computer and suffers from the absence of a pre-determined time structure as provided in traditional school classes. Furthermore, online learning usually presses students into a one-size-fits-all curriculum, which presents the same content to all students, regardless of their individual needs and learning styles. Any means of a personalization of content or individual feedback regarding problems they encounter are mostly ruled out by the discrepancy between the number of learners and the number of instructors. This results in a high demand for self-motivation and determination of MOOC participants. Social distance exists between individual students as well as between students and course instructors. It decreases engagement and poses a threat to learning success. Within this research, we approach the identified issues within MOOCs and suggest scalable technical solutions, improving social interaction and balancing content difficulty. Our contributions include situational interventions, approaches for personalizing educational content as well as concepts for fostering collaborative problem-solving. With these approaches, we reduce counterproductive struggles and create a universal improvement for future programming MOOCs. We evaluate our approaches and methods in detail to improve programming courses for students as well as instructors and to advance the state of knowledge in online education. Data gathered from our experiments show that receiving peer feedback on one's programming problems improves overall course scores by up to 17%. Merely the act of phrasing a question about one's problem improved overall scores by about 14%. The rate of students reaching out for help was significantly improved by situational just-in-time interventions. Request for Comment interventions increased the share of students asking for help by up to 158%. Data from our four MOOCs further provide detailed insight into the learning behavior of students. We outline additional significant findings with regard to student behavior and demographic factors. Our approaches, the technical infrastructure, the numerous educational resources developed, and the data collected provide a solid foundation for future research.