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 Development of a vendor independent quantum computing transpiler(2020) Wangler, ThomasIn 2019 a quantum computer took 200 seconds for a task for which a state-of-the-art classical supercomputer would need roughly 10,000 years. Quantum supremacy was shown and the development of quantum technology proceeds quickly. However, several aspects limit the implementation and execution of quantum circuits. The vendors of quantum computers provide their own proprietary software development kit (SDK) to execute quantum circuits on their quantum processing units (QPUs). Furthermore, the computers differ regarding various properties like the native gate set and the qubit connectivity. Therefore, quantum circuits cannot be executed on arbitrary QPUs, but there exists a tight coupling between a QPU and a quantum algorithm implementation. To decouple the development of a circuit from the QPU, this thesis proposes a quantum circuit analysis and transpilation framework that integrates quantum SDKs and enables the comparison and analysis of quantum circuits, as well as the export of executable circuits in the respective assembly language of QPUs from different vendors. Currently existing QPUs, also called Noisy Intermediate-Scale Quantum (NISQ) machines, have a very limited number of qubits and are prone to failure. Thus, the integration of different QPUs enhances the possibilities of quantum circuit developers and avoids the SDK lock-in. Additionally, a graphical user interface is developed to support the user in the whole process of importing, visualizing, editing, and simulating a quantum circuit, as well as, choosing a suitable QPU to execute the circuit.Item Open Access Evaluation of complex typological universals with language vectors and real-valued logics(2020) Dönicke, TillmannLanguage representations and typological universals have received increasing attention in computational linguistics over the past few years. Most approaches make use of binary language vectors from typological databases and/or focus on the correlation of only two typological variables at the same time. This thesis shows that real-valued logics can be used to evaluate even more complex formulae, as they are formulated by typologists, on continuous vectors from existing corpora. Syntactic language vectors are extracted from the Universal Dependencies treebanks (Nivre et al., 2016) and serve as the basis for the evaluation of word-order universals.Item Open Access Enabling multi-tenant scalable IoT platforms(2020) Ismaiel, MuhammadInternet of Things (IoT) platforms have multi-layer architectures that facilitate the provisioning, automation of connected devices, and monitoring. These platforms simplify development because they solve a lot of the problems and complexities in building an IoT application. IoT platforms are typically central components with many heterogeneous users, which leads to the effect that these platforms are essential for IoT scenarios and must not become a single point of failure. Furthermore, since many users access these platforms, scalability and multi-tenancy are crucial. The scalability of IoT platforms makes user applications stable and more comfortable to extend. In contrast, the multi-tenancy trait allows multiple tenants to access user applications at the same time. In this thesis, we examine every software stack layer of an IoT platform and explain different methods to make each layer scalable. Enabling multi-tenancy at the application layer and attaining scalability of message brokers, databases, the middleware as a whole, network layer, and device layer are the primary tasks for enabling multi-tenant scalable IoT platforms. To provide a solution to these tasks, we go through the research work already done in the area of scalability and multi-tenancy. We address multiple solutions for each task and also provide the best suitable solution for each task at the corresponding layer of an IoT platform.Item Open Access Travel service composition under temporal contraints(2020) Munawar, JavadanWeb service can be a software, application or a document available over the internet, the ever-rising use of these services have built immense trust for the general public, thus resulting in the need to make better, smart and efficient web services that can help cater the needs of the online community. A high number of services are on offer for a specific task makes it very competitive for the service providers to have an edge. When users start to make online requests for services it can result in rather complex queries which might not be solved by a single service and then service composition comes to play. There can be several methods, criterion and constraints which can be the basis of service composition. This Masters thesis was about composing services to solve queries that had some element of time, most of the times when a user makes a request to Virtual Personal Assistants like 'SIRI', these requests are simple and can be managed with ease using one service but sometimes if a user enters a complex request, it makes it a lot more demanding. Initially, the aim was to get the familiarity with the operations of how the assistants work, then get to know how the services are rendered for the user requests, then to get deep insight on how the services are composed and finally to set up an environment where some of the selected queries can be implemented. There were two options to have temporal reasoning based on the user queries, once after the query has been entered and secondly when the response from the service provider is received. After the research part, during the implementation phase, all the proposed and chosen queries were realised.Item Open Access About the design changes required for enabling ECM systems to exploit cloud technology(2020) Shao, GangSince the late 1980s, Enterprise Content Management Systems (ECM systems) have been used to store, manage, distribute all kinds of documents, media content, and information in enterprises. ECM systems also enable enterprises to integrate their business processes with contents, employing corporate information lifecycle and governance as well as automation of contents processing. The ever-changing business models and increasing demands have pushed ECM systems to evolve into a very active content repository with expectations such as high availability, high scalability, high customizability. These expectations soon became a costly financial burden for enterprises. The on-going hype around cloud computing has raised attention with its claims on improved manageability, less maintenance, and cost-effectiveness. Embracing the cloud might be a good solution for the next high-performance ECM system at an affordable price. To achieve such a goal, the designs of ECM systems must be changed before deployment into the cloud. Thus, this thesis aims to analyze the architecture design of legacy ECM systems, determine its shortcomings, and propose design changes required for embracing cloud technologies. The main proposal to design changes are i) decomposing an ECM system to its constituent components, ii) containerizing those components and create standard images, iii) decoupling the physical link between the data storage device from the applications container by utilizing docker volumes in dedicated persistent data containers instead, iv) utilizing software-defined network infrastructure where possible. These design changes then were tested with a proof-of-concept prototype, where an ECM product was successfully deployed and tested using Docker in a cloud environment backed by OpenStack.Item Open Access Using software-performance-antipatterns and profiling traces to perform code-refactorings(2020) Stadelmaier, NikoToday, usability, user satisfaction, as well as enterprise adoption of a software application, are highly influenced by the performance of the software application. Therefore, it is required to resolve performance issues as early as possible during the development of the software. Many issues can be resolved during the planning and design phase by integrating a model-based antipattern detection. Such approaches can be easily integrated with continuous development and integration pipelines, which are often used in modern software development following an agile development methodology. The focus of this thesis is to develop an approach that can automatically detect performance antipatterns and suggest refactorings for the found problems. In contrast to model-based approaches, the intention is to detect the problems on the code-level. To tackle the problem, we make use of profiling traces that record the execution of an application. After the initial research on antipatterns in Go, we introduce the identified code-based antipatterns. We then present the benchmark application, where we implemented the problems. This benchmark is then used to generate the profile traces. Now, we analyze how the problems can be detected in the profiles. We then extract our novel code- and profile-patterns from the profiling information. These patterns are then used by our detection tool to identify the problems in the profiles and suggest the respective refactorings. Our results show that our approach can automatically detect performance antipatterns in the profiling data. However, more tests need to be conducted to conclude if the approach can detect antipatterns in the data of other systems.Item Open Access PISM Performance Profiling - Analyse einer Eisschild Simulation(2020) Van Craen, AlexanderIn der vorliegenden Masterarbeit wird der aktuelle Performancestand des Parallel Ice Sheet Model (PISM) evaluiert. Eine allgemeine Übersichtsanalyse ergibt, dass die Performance von PISM sowohl durch die Speicherbandbreite, also auch Netzwerkbandbreite und -latenz limitiert ist. Auf dieser Analyse aufbauend, werden ebenfalls mittels, sowohl automatisch generierten, als auch theoretisch hergeleiteten, Roofline Modellen, sowie Laufzeitmessungen einzelner Programmabschnitte die laufzeitkritischen Abschnitte identifiziert und analysiert. Für die herauskristallisierten Flaschenhälse und Hotspots, werden verschiedene Verbesserungsansätze dargelegt und diskutiert. Die detaillierte Analyse der Stressgleichungen ergibt beispielsweise eine mögliche Laufzeitreduzierung eben dieser um über 80 %. Anhand einer Implementierung wird die Umsetzbarkeit ausgewählter Verbesserungsansätze überprüft. Die Ergebnisse dieser Masterarbeit sind dabei von primärem Interesse für die PISM Entwickler. Das Vorgehen in dieser Arbeit ist exemplarisch für eine Performanceanalyse großer und kleiner Projekte und kann damit als Grundlage für weitere Analysen dienen, sodass die Masterarbeit auch für Leute interessant ist, die sich mit der Performance von wissenschaftlichem Programmcode auseinandersetzen.Item Open Access Service-oriented design of energy management systems for microgrids(2020) Hossain, AmimulMicrogrids are low-voltage, reliable, economic, renewable energy resources that help to reduce the increasing demand of energy. Microgrids are environmentally friendly because of their renewable energy resources. The installations of various renewable energy resources are increasing day by day to produce vast amounts of energy. The management of produced energy is operated by a central software system, called Energy Management System (EMS). According to our literature review of microgrid EMSs, we notice that the capabilities of traditional EMSs are limited, and these are tightly coupled with the EMSs. This is considered as an obstacle for sustainable development of microgrid EMSs. We need EMSs whose capabilities have to be flexible, reusable, and interoperable against the traditional EMSs that ensure the sustainability of EMSs. Based on our literature review, we find that the Service-Oriented Computing (SOC) is a computing paradigm that helps to develop a flexible, reusable, and interoperable EMS. In this thesis, we propose to design EMS based on the design principles of SOC. We design five categories of RESTful Web services to develop service-oriented EMSs for microgrids. By using these RESTful Web services a sustainable micorgrid EMS can be developed. We design and implement a small service-oriented microgrid EMS by using our designed Web services that simulate distributed energy resources (wind turbine, photovoltaic) and distributed energy storage (battery). We use real energy consumption data with the simulated data to make the system operational.Item Open Access Property-based testing : evaluating its applicability and effectiveness for AUTOSAR basic software(2020) Bose, AparnaPrevious work has shown that Property-based Testing (PBT) can be successfully applied to testing synchronous software. For example, it has been demonstrated that PBT can be applied to testing cloud services, web services and telecoms software. But less research has been carried out to evaluate this approach to testing asynchronous code as in automotive software. In the work presented in this Master thesis, the data generation feature of PBT is exploited to test the functionality of a software module based on the AUTOSAR Adaptive Platform. Properties are defined considering the system as a black-box targeting its functionality on an abstract level. First, we apply stateless properties to test a single functionality and thereby find the communication delay needed to incorporate in our testing at system level. Later, we implement a test infrastructure based on stateful properties using the Python tool Hypothesis for the demonstration of research based on PBT. The testing framework is interfaced with the runtime environment to integrate the former with the system being tested. The test inputs generated in this approach are evaluated for their effectiveness and efficiency in testing the software module under test. Finally, experts in the testing field have been interviewed to draw comparisons between PBT and traditional methods of testing.Item Open Access An analytics framework for the IoT platform MBP(2020) Kumar, AbishekThe emergence of IoT has introduced a huge amount of applications that generate massive amounts of data at a high rate. This data stream needs intelligent data processing and analysis. The evolution of Smart cities and Smart industries has resulted into an ocean of data from millions of sensors and devices. Surveillance systems, telecommunication systems, smart devices, and smart cars are some examples of such systems. However, this data itself doesn’t provide any information unless it is analysed. This results into a need of analytics tools and frameworks which can efficiently analyse this data and provide with useful information. Analytics is all about inspection, transformation and modelling of data to achieve information that further suggests and assists in decision making. In a world of IoT, analytics has a crucial role to play to improve life and better manage the infrastructure in a secure, sustainable and cost effective manner. The smart sensor network serves as the base for IoT. In this context, one of the major tasks is to develop advanced analytics frameworks for the interpretation of data provided by the sensors. MBP is a platform for managing IoT environments. Sensors and devices can be registered to this platform and the status of sensors can be viewed and modified from the platform. This platform will be used to collect data from the sensors and devices connected to the platform. There are two types of mining that can be performed on raw data, one technique analyses the data on the fly as it is received (Data Stream Mining) and the other can be performed on demand on the data collected for a longer period of time (Batch Processing). Both types of analysis has its own advantages. Lambda architecture is a data analytics architecture which allows us to perform both stream analysis and batch processing on the same data. This architecture defines some practical and well versed principles of handling big data. The pattern allows us to deal with both real time and historical data, but the analysis is performed separately and does not affect each other. In this thesis, we will create an analytics framework for the MBP IoT platform based on the lambda architecture.