05 Fakultät Informatik, Elektrotechnik und Informationstechnik
Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/6
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Item Open Access Strukturierte Modellierung von Affekt in Text(2020) Klinger, Roman; Padó, Sebastian (Prof. Dr.)Emotionen, Stimmungen und Meinungen sind Affektzustände, welche nicht direkt von einer Person bei anderen Personen beobachtet werden können und somit als „privat“ angesehen werden können. Um diese individuellen Gefühlsregungen und Ansichten dennoch zu erraten, sind wir in der alltäglichen Kommunikation gewohnt, Gesichtsausdrücke, Körperposen, Prosodie, und Redeinhalte zu interpretieren. Das Forschungsgebiet Affective Computing und die spezielleren Felder Emotionsanalyse und Sentimentanalyse entwickeln komputationelle Modelle, mit denen solche Abschätzungen automatisch möglich werden. Diese Habilitationsschrift fällt in den Bereich des Affective Computings und liefert in diesem Feld Beiträge zur Betrachtung und Modellierung von Sentiment und Emotion in textuellen Beschreibungen. Wir behandeln hier unter anderem Literatur, soziale Medien und Produktbeurteilungen. Um angemessene Modelle für die jeweiligen Phänomene zu finden, gehen wir jeweils so vor, dass wir ein Korpus als Basis nutzen oder erstellen und damit bereits Hypothesen über die Formulierung des Modells treffen. Diese Hypothesen können dann auf verschiedenen Wegen untersucht werden, erstens, durch eine Analyse der Übereinstimmung der Annotatorinnen, zweitens, durch eine Adjudikation der Annotatorinnen gefolgt von einer komputationellen Modellierung, und drittens, durch eine qualitative Analyse der problematischen Fälle. Wir diskutieren hier Sentiment und Emotion zunächst als Klassifikationsproblem. Für einige Fragestellungen ist dies allerdings nicht ausreichend, so dass wir strukturierte Modelle vorschlagen, welche auch Aspekte und Ursachen des jeweiligen Gefühls beziehungsweise der Meinung extrahieren. In Fällen der Emotion extrahieren wir zusätzlich Nennungen des Fühlenden. In einem weiteren Schritt werden die Verfahren so erweitert, dass sie auch auf Sprachen angewendet werden können, welche nicht über ausreichende annotierte Ressourcen verfügen. Die Beiträge der Habilitationsarbeit sind also verschiedene Ressourcen, für deren Erstellung auch zugrundeliegende Konzeptionsarbeit notwendig war. Wir tragen deutsche und englische Korpora für aspektbasierte Sentimentanalyse, Emotionsklassifikation und strukturierte Emotionsanalyse bei. Des Weiteren schlagen wir Modelle für die automatische Erkennung und Repräsentation von Sentiment, Emotion und verwandten Konzepten vor. Diese zeigen entweder bessere Ergebnisse, als bisherige Verfahren oder modellieren Phänomene erstmalig. Letzteres gilt insbesondere bei solchen Methoden, welche auf durch uns erstellte Korpora ermöglicht wurden. In den verschiedenen Ansätzen werden wiederkehrend Konzepte gemeinsam modelliert, sei es auf der Repräsentations- oder der Inferenzebene. Solche Verfahren, welche Entscheidungen im Kontext treffen, zeigen in unserer Arbeit durchgängig bessere Ergebnisse, als solche, welche Phänomene getrennt betrachten. Dies gilt sowohl für den Einsatz künstlicher neuronaler Netze, als auch für die Verwendung probabilistischer graphischer Modelle.Item Open Access Performance measurements for personalizable route planning for uncorrelated edge costs(2021) Bühler, FelixNowadays, ordinary route planners compute paths by choosing the shortest or fastest route. However, there exist additional metrics from which users with varying preferences could benefit. Personalized route planning offers the possibility to combine different metrics with personal preferences. Nevertheless, personalized route planning has mainly been tested with correlated metrics. But when including uncorrelated metrics, the computing time increases significantly. Previous work found that the speedup technique “Customizable Route Planning” can lead to feasible speedups for single metric calculations. Thus, in this work, we investigate how this speedup technique for Dijkstra improves the query performances of “Personalizable Route Planning” compared to “Personalizable Contraction Hierarchies”. Furthermore, we study the performances on uncorrelated metrics. We introduce a graph structure to compare the personalized speedup techniques “Personalizable Contraction Hierarchies”, “Personalizable Customizable Route Planning” and “Personalizable Route Planning”. Three graph partitioning algorithms have been implemented to realize “Customizable Route Planning”: K-means, Gonzales, and Merge. Our experiments show that Merge works well in combination with “Personalizable Contraction Hierarchies” preprocessing. We found that “Personalizable Customizable Route Planning” is a good alternative, as it uses much fewer edges for finding the costs of the shortest path. For uncorrelated metrics, “Personalizable Customizable Route Planning” and “Personalizable Route Planning” achieved speedups higher than “Personalizable Contraction Hierarchies”. Our contribution comprises a novel graph structure for comparing different Dijkstra variants. With our experiments, we provide a deeper understanding of the personalized route planning problem. Additionally, we propose improvements for “Personalizable Contraction Hierarchies” for less contracted graphs with uncorrelated metrics.Item Open Access Developing a multimodal feedback motion guidance system in VR for people with motion disabilities(2021) Wennrich, KevinMotion is an important aspect in the area of physiotherapy. The correctness of those motions is even more important, especially in the home exercises. In this thesis, the prototype of a multimodal guidance system in virtual reality, which tracks the movements of the users and compares it to the correct position in the field of physiotherapy exercises was created. The get the requirements for the system, people who needed to go to physiotherapy, because of an injury or a disability (stroke, MS, NPC), were interviewed, as well as a physiotherapist. Based on the results, we have implemented a virtual physiotherapist and the auditory guidance as two modalities. Further modalities have been the ghostarm and the haptic guidance as vibration bands. The prototype in which the user can choose and combine the guidances have been developed. The system, the modalities and its limits have been evaluated in a online study and a pilot study, with the results, that until now the ghostarm and virtual physiotherapist are the most liked guidances. A user study is planned for the future.Item Open Access Adaption des Systems XSTAMPP 4 an die Analysemethode STAMP/CAST in der Einzelplatzanwendung(2020) Zimmermann, EvaTäglich geschehen Unfälle, die analysiert werden müssen und für die Erklärungen gefunden warden sollten. Dazu gibt es einen Analyseprozess CAST, der auf STAMPP aufbauend, existierende Unfälle betrachtet und durch dessen Erkenntnisse weitere Unfälle verhindert werden sollen. Um diesen Prozess zu unterstützen, wird in dieser Bachelorarbeit eine Einzelplatzanwendung umgesetzt, die den Anwender bei der Analyse von Unfällen unterstützt. Dafür wurde aufbauend auf der Theorie und den existierenden Arbeiten, eine Anforderungsanalyse durchgeführt, auf dessen Grundlage dann die Einzelplatzanwendung implementiert wurde. Als Ergebnis der Arbeit wurde eine Software fertiggestellt, die es dem Analyst ermöglicht, alle Schritte von CAST durchzuführen.Item Open Access Task-oriented specialization techniques for entity retrieval(2020) Glaser, Andrea; Kuhn, Jonas (Prof. Dr.)Finding information on the internet has become very important nowadays, and online encyclopedias or websites specialized in certain topics offer users a great amount of information. Search engines support users when trying to find information. However, the vast amount of information makes it difficult to separate relevant from irrelevant facts for a specific information need. In this thesis we explore two areas of natural language processing in the context of retrieving information about entities: named entity disambiguation and sentiment analysis. The goal of this thesis is to use methods from these areas to develop task-oriented specialization techniques for entity retrieval. Named entity disambiguation is concerned with linking referring expressions (e.g., proper names) in text to their corresponding real world or fictional entity. Identifying the correct entity is an important factor in finding information on the internet as many proper names are ambiguous and need to be disambiguated to find relevant information. To that end, we introduce the notion of r-context, a new type of structurally informed context. This r-context consists of sentences that are relevant to the entity only to capture all important context clues and to avoid noise. We then show the usefulness of this r-context by performing a systematic study on a pseudo-ambiguity dataset. Identifying less known named entities is a challenge in named entity disambiguation because usually there is not much data available from which a machine learning algorithm can learn. We propose an approach that uses an aggregate of textual data about other entities which share certain properties with the target entity, and learn information from it by using topic modelling, which is then used to disambiguate the less known target entity. We use a dataset that is created automatically by exploiting the link structure in Wikipedia, and show that our approach is helpful for disambiguating entities without training material and with little surrounding context. Retrieving the relevant entities and information can produce many search results. Thus, it is important to effectively present the information to a user. We regard this step beyond the entity retrieval and employ sentiment analysis, which is used to analyze opinions expressed in text, in the context of effectively displaying information about product reviews to a user. We present a system that extracts a supporting sentence, a single sentence that captures both the sentiment of the author as well as a supportingfact. This supporting sentence can be used to provide users with an easy way to assess information in order to make informed choices quickly. We evaluate our approach by using the crowdsourcing service Amazon Mechanical Turk.Item Open Access A systematic mapping study on development and use of AI planning tools(2021) Philippsohn, RobertArtificial intelligence (AI) planning is a big area in the AI field with many needs and special problems. Therefore, it needs tools to suit these special problems and request, as well as for trends in the AI planning community. Since 1971 there has been an influx of many tools that assist insolving planning problems and making plans. To give a better overview of the available landscape of AI planning tools this systematic mapping study was conducted and try also to shows what software engineering principles are used in creating the tools. We also try to depict in which industry domains the AI planning tools are used and how many papers mention the tools being used in the industry. In the end, we conclude that there are at least 106 different tools out there, with only a fraction being used in the industry. While only a small part of the tools are talked about being used in the industry, this small part is covering a wide array of industry domains.Item Open Access Verifiable tally-hiding E-voting with fully homomorphic encryption(2020) Hasler, SebastianAn E-voting system is end-to-end verifiable if arbitrary external parties can check whether the result of the election is correct or not. It is tally-hiding if it does not disclose the full election result but rather only the relevant information, such as e.g. the winner of the election. In this thesis we pursue the goal of constructing an end-to-end verifiable tally-hiding E-voting system using fully homomorphic encryption. First we construct an alteration of the GSW levelled fully homomorphic encryption scheme based on the learning with errors over rings assumption. We utilize a key homomorphic property of this scheme in order to augment the scheme by a distributed key generation and distributed decryption. This leads to a passively secure 4-round multi-party computation protocol in the common random string model that can evaluate arithmetic circuits of arbitrary size. The complexity of this protocol is quasi-linear in the number of parties, polynomial in the security parameter and polynomial in the size of the circuit. By using Fiat-Shamir-transformed discrete-log-based zero-knowledge proofs we achieve security against active adversaries in the random oracle model while preserving the number of 4 rounds. Based on this actively secure protocol we construct an end-to-end verifiable tally-hiding E-voting system that has quasi-linear time complexity in the number of voters.Item Open Access Entwicklung einer höchsteffizienten, weichschaltenden Totem-Pole PFC Stufe basierend auf GaN Transistoren(2020) Lu, SiyuanIn der Arbeit wird eine Totem-Pole Power Factor Correction (PFC1)-Stufe vorgestellt, die als die Eingangsstufe für ein zweistufiges Ladegerät für E-Bike mit Nennleistung 180 W arbeitet. Und die Ausgangsspannung ist zwischen 360 V und 400 V einstellbar. Die PFC ist auf GaN2-HEMT3 von TI4 basiert und so aufgebaut, dass sie in zwei unterschiedlichen Modulationsverfahren betreiben kann:Triangular Current Mode(TCM5) und Continuous Current Mode(CCM6). Bei CCM wird die PFC mit konstanter Schaltfrequenz und Hart Switsching betrieben. Dagegen arbeitet sie bei TCM mit variabler Schaltfrequenz und Zero Voltage Switching(ZVS7), die zu besserem Wirkungsgrad und schlechterem Leistungsfaktor(PF8) im Vergleich zu bei CCM führt. Die Hauptaufgabe der Arbeit ist Entwurf, Aufbau und Inbetriebnahme der PFC-Stufe. Und die Messungen für Verläufe der elektrischen Größen, Wirkungsgrad und Temperatur der Bauteile werden bei unterschiedlicher Systemkonfigurationen durchgeführt, um die Entwurf und Aufbau zu validieren und Systemverhalten zu vergleichen. Der maximale Wirkungsgrad des Systems erreicht über 99 % durch die Anwendung von GaN-HEMT und TCM.Item Open Access Elastic parallel systems for high performance cloud computing(2020) Kehrer, Stefan; Blochinger, Wolfgang (Prof. Dr.)High Performance Computing (HPC) enables significant progress in both science and industry. Whereas traditionally parallel applications have been developed to address the grand challenges in science, as of today, they are also heavily used to speed up the time-to-result in the context of product design, production planning, financial risk management, medical diagnosis, as well as research and development efforts. However, purchasing and operating HPC clusters to run these applications requires huge capital expenditures as well as operational knowledge and thus is reserved to large organizations that benefit from economies of scale. More recently, the cloud evolved into an alternative execution environment for parallel applications, which comes with novel characteristics such as on-demand access to compute resources, pay-per-use, and elasticity. Whereas the cloud has been mainly used to operate interactive multi-tier applications, HPC users are also interested in the benefits offered. These include full control of the resource configuration based on virtualization, fast setup times by using on-demand accessible compute resources, and eliminated upfront capital expenditures due to the pay-per-use billing model. Additionally, elasticity allows compute resources to be provisioned and decommissioned at runtime, which allows fine-grained control of an application's performance in terms of its execution time and efficiency as well as the related monetary costs of the computation. Whereas HPC-optimized cloud environments have been introduced by cloud providers such as Amazon Web Services (AWS) and Microsoft Azure, existing parallel architectures are not designed to make use of elasticity. This thesis addresses several challenges in the emergent field of High Performance Cloud Computing. In particular, the presented contributions focus on the novel opportunities and challenges related to elasticity. First, the principles of elastic parallel systems as well as related design considerations are discussed in detail. On this basis, two exemplary elastic parallel system architectures are presented, each of which includes (1) an elasticity controller that controls the number of processing units based on user-defined goals, (2) a cloud-aware parallel execution model that handles coordination and synchronization requirements in an automated manner, and (3) a programming abstraction to ease the implementation of elastic parallel applications. To automate application delivery and deployment, novel approaches are presented that generate the required deployment artifacts from developer-provided source code in an automated manner while considering application-specific non-functional requirements. Throughout this thesis, a broad spectrum of design decisions related to the construction of elastic parallel system architectures is discussed, including proactive and reactive elasticity control mechanisms as well as cloud-based parallel processing with virtual machines (Infrastructure as a Service) and functions (Function as a Service). To evaluate these contributions, extensive experimental evaluations are presented.Item Open Access Evaluating human-computer interfaces for specification and comprehension of transient behavior in microservice-based software systems(2020) Beck, SamuelModern software systems are subject to constant change while operating in production. New agile development methods such as continuous deployment and DevOps enable developers to deploy code changes frequently. Also, failures and self-adaptation through mechanisms such as elastic scaling and resilience patterns introduce changes into a system during runtime. For that reason, these systems that become more complex and distributed continuously exhibit transient behavior, the state that occurs while transitioning from one state to another. To make statements about a system’s reliability and performance, it is imperative that this transient behavior is specified in non-functional requirements and that stakeholders can review whether these requirements are met. However, due to the complexity of this behavior and the accompanying specifications, only experts can achieve this. This thesis aims to make the specification of non-functional requirements for, and the comprehension of, transient behavior in microservice systems more accessible, particularly for stakeholders that lack expert knowledge about transient behavior. To achieve this, novel approaches are explored that utilize modern human-computer interaction methods to facilitate this problem. At first, the state of the art in transient behavior in software systems, human-computer interaction, and software visualization is presented. Subsequently, expert interviews are conducted to understand how transient behavior is handled in practice and which requirements experts have to an envisioned solution. Based on this, a concept for a solution is proposed, which integrates different visualizations with a chatbot, and implemented as a prototype. Finally, the prototype is evaluated in an expert study. The evaluation shows that the approach can support software architects and DevOps engineers to create and verify specifications for transient behavior. However, it also reveals that the prototype can still be improved further. Furthermore, it was shown that the integration of a chatbot into the solution was not helpful for the participants. In conclusion, human-computer interaction and visualization methods can be applied to the problems of specifying and analyzing transient behavior to support software architects and engineers. The developed prototype shows potential for the exploration of transient behavior. The evaluation also revealed many opportunities for future improvements.