Weiterentwicklung analytischer Datenbanksysteme

This thesis contributes to the state of the art in analytical database systems. First, we identify and explore extensions to better support analytics on event streams. Second, we propose a novel polygon index to enable efficient geospatial data processing in main memory. Third, we contribute a new deep learning approach to cardinality estimation, which is the core problem in cost-based query optimization.Diese Arbeit trägt zum aktuellen Forschungsstand von analytischen Datenbanksystemen bei. Wir identifizieren und explorieren Erweiterungen um Analysen auf Eventströmen besser zu unterstützen. Wir stellen eine neue Indexstruktur für Polygone vor, die eine effiziente Verarbeitung von Geodaten im Hauptspeicher ermöglicht. Zudem präsentieren wir einen neuen Ansatz für Kardinalitätsschätzungen mittels maschinellen Lernens

Heterogeneity in IT Landscapes and Monopoly Power of Firms: A Model to Quantify Heterogeneity

The term heterogeneity is widely used to describe complex IT systems and can refer to various characteristics, such as vendor, technology, or semantic diversity of the systems components. However, no commonly accepted definition or quantification of this “diversity” can be found in IS literature. In this article we transfer well-studied measures from other disciplines (especially economics and the anti-monopoly legislation) to heterogeneity in IT landscapes. The two main contributions of this article are A) the definition of heterogeneity in an IT landscape as a statistical property – which therefore can be measured by statistical indexes and B) a generic approach to quantify heterogeneity in IT landscapes. The applicability of the conceptualization and the approach to quantify heterogeneity is demonstrated in two real IT organizations

The cloud-to-edge-to-IoT continuum as an enabler for search and rescue operations

When a natural or human disaster occurs, time is critical and often of vital importance. Data from the incident area containing the information to guide search and rescue (SAR) operations and improve intervention effectiveness should be collected as quickly as possible and with the highest accuracy possible. Nowadays, rescuers are assisted by different robots able to fly, climb or crawl, and with different sensors and wireless communication means. However, the heterogeneity of devices and data together with the strong low-delay requirements cause these technologies not yet to be used at their highest potential. Cloud and Edge technologies have shown the capability to offer support to the Internet of Things (IoT), complementing it with additional resources and functionalities. Nonetheless, building a continuum from the IoT to the edge and to the cloud is still an open challenge. SAR operations would benefit strongly from such a continuum. Distributed applications and advanced resource orchestration solutions over the continuum in combination with proper software stacks reaching out to the edge of the network may enhance the response time and effective intervention for SAR operation. The challenges for SAR operations, the technologies, and solutions for the cloud-to-edge-to-IoT continuum will be discussed in this paper

An IoT Platform for Epilepsy Monitoring and Supervising

Epilepsy is a chronic neurological disorder with several different types of seizures, some of them characterized by involuntary recurrent convulsions, which have a great impact on the everyday life of the patients. Several solutions have been proposed in the literature to detect this type of seizures and to monitor the patient; however, these approaches lack in ergonomic issues and in the suitable integration with the health system. This research makes an in-depth analysis of the main factors that an epileptic detection and monitoring tool should accomplish. Furthermore, we introduce the architecture for a specific epilepsy detection and monitoring platform, fulfilling these factors. Special attention has been given to the part of the system the patient should wear, providing details of this part of the platform. Finally, a partial implementation has been deployed and several tests have been proposed and carried out in order to make some design decisions

Methodology for sizing and optimising a Blended Wing-Body with distributed electric ducted fans

The increase of air traffic in the last decades and its projections pose a key challenge towards the carbon neutral growth objective. To cope with this societal goal, there is a need for disruptive air transport aircraft concepts featuring new technologies with low environmental impact. Such future air vehicle relies on the various interactions between systems, disciplines and components. This Ph.D. research thus focuses on the development of a methodology dedicated to the exploration and performance evaluation of unconventional configurations using innovative propulsion concepts. The use case to be considered is the optimisation at conceptual level of a Blended Wing-Body with distributed electric propulsion, a promising concept which combines high aerodynamic performances and benefits from electric propulsion. The optimisation process based on FAST, the ISAE-SUPAERO / ONERA aircraft sizing tool, has been implemented within OpenMDAO, the NASA open-source multidisciplinary analysis and optimisation framework. With the idea of a progressive enhancement of the multidisciplinary design analysis and a better capture of the different effects, the two pioneering elements have been studied separately. First, the classical process has been revised to take into account the new hybrid powerplant. Second, a methodology has been revised to consider a radically new airframe design. Last, a design process featuring both innovative aspects has been developed to investigate a Blended Wing Body concept with distributed electric propulsion. Concerning the design process, results show that the use of gradients in the optimisation procedure speeds up the process against a gradient-free method up to 70%. This is an important gain in time that facilitates designer’s tasks. For the disruptive concept performances, results have been compared to the ones obtained for a conventional A320 type aircraft based on the same top level requirements and technological horizon. Overall, the hybrid electric propulsion concept is interesting as it allows zero emissions for Landing/Take-Off operations, improving the environmental footprint of the aircraft: fuel can be saved for missions below a certain range. This limitation is associated to the presence of batteries: indeed they introduce indeed a relevant penalty in weight that cannot be countered by benefits of electrification for longer range. Additional simulations indicate that a Blended Wing-Body concept based on a turbo-electric only architecture is constantly performing better than the baseline within the limits of the assumptions

Righteous Remixes, Sacred Mashups: Rethinking Authority, Authenticity, and Originality in the Study of Religion

This dissertation sets out to place emergent theories of “remix” in conversation with scholarship exploring changes in the definitions and practices associated with the word “religion.” Through particular case studies, the dissertation analyzes the ways that certain contemporary creators, writers, and influencers have emerged as constructors of contemporary Buddhism. Specifically building upon the critiques of religion put forth by Jonathan Z. Smith, Russell T. McCutcheon, Brent Nongbri, Jane Iwamura, and others, I am concerned with how individuals who are not part of the religious studies scholarly community participate in the processes of constructing religion, and in this case, in constructing and contributing to changes in a specifically North American and European understanding of Buddhism. Utilizing an approach that centers on the art of metaphor, and employing a model for specifically studying cultural constructs via remix theory that I term Remix+/-, I explore the ways that a few influential leaders, including Stephen Batchelor, Osamu Tezuka, and Jon Kabat-Zinn, express and advocate for certain approaches to practices, rituals, and beliefs that are ostensibly related to historic forms of Buddhism. I argue that the ways they make their claims are best understood in relation to patterned metaphorical assumptions about religion. I further highlight the ways that these individuals are able to leverage technologies, rhetorics, and techniques in order to lay their claim – directly or indirectly – to authority, originality, and authenticity. Finally, I argue that these emergent leaders may be understood as exemplars not only of changes to Buddhism that are occurring today, but of what is likely to happen in the future with increasing speed. This speed and direction of change in “religion” is due to the affordances of digital technologies that intensify existing relations of power and amplify the views of those positioned, as these leaders are, to lay claim to certain linguistic, cultural, geographic, and technological resources as they participate in the construction of an emergent form of what they argue is Buddhism