Prof. Xavier Mestre | February 25, 2019 | 11:00 | S.1.42

Abstract:

Conventional tools in array signal processing have traditionally relied on the availability of a large number of samples acquired at each sensor or array element (antenna, hydrophone, microphone, etc.). Large sample size assumptions typically guarantee the consistency of estimators, detectors, classifiers and multiple other widely used signal processing procedures. However, practical scenario and array mobility conditions, together with the need for low latency and reduced scanning times, impose strong limits on the total number of observations that can be effectively processed. When the number of collected samples per sensor is small, conventional large sample asymptotic approaches are not relevant anymore. Recently, large random matrix theory tools have been proposed in order to address the small sample support problem in array signal processing. In fact, it has been shown that the most important and longstanding problems in this field can be reformulated and studied according to this asymptotic paradigm. By exploiting the latest advances in large random matrix theory and high dimensional statistics, a novel and unconventional methodology can be established, which provides an unprecedented treatment of the finite sample-per-sensor regime. In this talk, we will see that random matrix theory establishes a unifying framework for the study of array signal processing techniques under the constraint of a small number of observations per sensor, which has radically changed the way in which array processing methodologies have been traditionally established. We will show how this unconventional way of revisiting classical array processing has lead to major advances in the design and analysis of signal processing techniques for multidimensional observations.

Bio:

Xavier Mestre received the MS and PhD in Electrical Engineering from the Technical University of Catalonia (UPC) in 1997 and 2002 respectively and the Licenciate Degree in Mathematics in 2011. During the pursuit of his PhD, he was recipient of a 1998-2001 PhD scholarship (granted by the Catalan Government) and was awarded the 2002 Rosina Ribalta second prize for the best doctoral thesis project within areas of Information Technologies and Communications by the Epson Iberica foundation. From January 1998 to December 2002, he was with UPC’s Communications Signal Processing Group, where he worked as a Research Assistant and participated actively in several European-funded projects. In January 2003 he joined the Telecommunications Technological Center of Catalonia (CTTC), where he currently holds a position as a Senior Research Associate and head of the Advanced Signal and Information Processing Department. During this time, he has actively participated in 8 European projects and two ESA contracts. He has been coordinator of the European ICT project EMPhAtiC (2012-15) and has participated in 6 industrial contracts, some of which have lead to commercialized products. He is author of three granted patents, 9 book chapters, 41 international journal papers and more than 90 articles in international conferences. He has been associate editor of the IEEE Transactions on Signal Processing (2008-11, 2015-present) and associate co-editor of the special issue on Cooperative Communications in Wireless Networks at the EURASIP Journal on Wireless Communications and Networking. He is IEEE Senior member and elected member of the IEEE Sensor Array and Multi-channel Signal Processing technical committee (2013-2018) and the EURASIP Special Area Teams on “Theoretical and  Methodological Trends in Signal Processing” (2015-present) and “Signal Processing in Communications” (2018-present). He has participated in the organization of multiple conferences and scientific events, such as the “IEEE Wireless Communications and Networking Conference 2018″ (general vice-chair), the “IEEE International Symposium on Power Line Communications” (technical chair), the “European Wireless 2014″ (general co-chair), the “European Signal Processing Conference 2011″ (general technical chair), the “IEEE Winter School on Information Theory” 2011 (general co-chair), the “Summer School on Random Matrix Theory for Wireless Communications” 2006 (general chair). He is general chair of the IEEE International Conference on Acoustics, Speech and Signal Processing 2020.

Priv.-Doz. Dr. Rick Rabiser | February 7, 2019 | 10:00 | S.2.42

Abstract

Complex software-intensive systems are often described as systems of systems (SoS) due to their heterogeneous architectural elements. As SoS behavior is often only understandable during operation, runtime monitoring is needed to detect deviations from requirements. Today, while diverse monitoring approaches exist, most do not provide what is needed to monitor SoS, e.g., support for dynamically defining and deploying diverse checks across multiple systems. In this talk, I will describe our experiences of developing, applying, and evolving an approach for monitoring an SoS in the domain of industrial automation software, that is based on a domain-specific language (DSL). I will first describe our initial approach to dynamically define and check constraints in SoS at runtime, including a demo of our monitoring tool REMINDS, and then motivate and describe its evolution based on requirements elicited in an industry collaboration project. I will furthermore describe solutions we have developed to support the evolution of our approach, i.e., a code generation approach and a framework to automate testing the DSL after changes. We evaluated the expressiveness and scalability of our new DSL-based approach using an industrial SoS. At the end of the talk, I will also present general lessons we learned and give an overview of other projects in the area of software monitoring as well as other areas such as software product lines, that I am currently involved in.

Bio

Rick Rabiser (http://mevss.jku.at/rabiser) is currently a senior researcher at the Christian Doppler Laboratory for Monitoring and Evolution of Very-Large-Scale Software Systems (VLSS) at Johannes Kepler University Linz, Austria. In this lab, he heads the research module on requirements-based monitoring and diagnosis in VLSS evolution, with Primetals Technologies Austria as industry partner. He holds a Master’s and a Ph.D. degree in Business Informatics as well as the venia docendi (Habilitation) in Practical Computer Science from Johannes Kepler University Linz. His research interests include but are not limited to variability management, software maintenance and evolution, systems and software product lines, automated software engineering, requirements engineering, requirements monitoring, and usability and user interface design. Dr. Rabiser co-authored over 120 (peer-reviewed) publications; served in 80+ program committees and 25+ conference and workshop organization committees; and frequently reviews articles for several international journals like IEEE TSE, IEEE TSC, ACM CSUR, EMSE, JSS, and IST. He is also a member of the steering committee of the Euromicro SEAA conference series and a member of the Euromicro Board of Directors (Director for Austria) and the Euromicro Executive Office (Publicity Secretary). He is also an elected member of the steering committee of the International Systems and Software Product Line Conference (SPLC). He currently is the speaker of computer scientists at JKU Linz, who are not full professors (Fachbereichssprecher Mittelbau Informatik).

Prof. Giorgio Brajnik | January 23, 2019 | 11:00 | N.1.42 (Germanistik)

Abstract

Testing lies at the heart of software development. Tightly woven with requirements engineering, the testing process influences how software is developed and its quality.  With adoption of agile and devops approaches, the continuous testing process has to rely on a testing strategy that is multi-level and has to balance test automation and exploratory testing.  Because so many things need to be tested, and because the system under test changes very often and rapidly, effectiveness and sustainability of the testing process is a must.

I will present an approach for automating end-to-end testing that is based on UML specifications of the behavior of the system and a toolkit that automatically generates source code supporting definition of high level test cases and related artifacts. In this way, a software development team can avoid dealing with low level details and focus instead on what needs to be tested, what test conditions need to be covered, how test results affect requirements coverage. This kind of information constitutes then a living documentatio of the system specification which can be used to guide exploratory testing. Such an approach is currently being used in mobile apps (in the area of workforce management) and web apps (in the financial domain).

Bio

Giorgio Brajnik is associate professor at the Computer Science Department of the University of Udine, Italy. He holds a degree in Computer Science (from the University of Udine) and a PhD in Computer Science (from the University of Manchester). After working on information search systems, since 1999 his focus is on methods for effective assessment of accessibility and quality of websites and web applications and more recently on model-based techniques for analysis of user interfaces.

At the university he teaches courses on object oriented programming and accessibility and user centered web development.  In ’92 and ’95-’96 he was visiting scholar at the University of Texas at Austin. He has been invited lecturer, panelist and visiting professor in Europe, the U.S. and New Zealand. He participated to several of the W3C working groups dealing with accessibility. He also supervised the development of accessibility testing tools when he was working with a company he cofounded, Usablenet Inc.  Currently he is scientific advisor for Interaction Design Solutions, a startup company he co-founded that is specialized on model-driven techniques for software system testing.

He is program committee member of several conferences, including the International Cross-Disciplinary Conference on Web Accessibility and ACM Assets, for which he was co-chair of the Doctoral Consortium  and also General Chair; he is regular reviewer for several journals. Additional details are available at www.dimi.uniud.it/giorgio/vitae.html.

The review of the TEWI colloquium of Abdelhak Bentaleb from December 13, 2018 comprises the slides (below):

Abstract: Past research has shown that concurrent HTTP adaptive streaming (HAS) players behave selfishly and the resulting competition for shared resources leads to underutilization or oversubscription of the network, presentation quality instability and unfairness among the players, all of which adversely impact the viewer experience. While coordination among the players, as opposed to all being selfish, has its merits and may alleviate some of these issues. A fully distributed architecture is still desirable in many deployments and better reflects the design spirit of HAS. In this study, we focus on and propose a distributed bitrate adaptation scheme for HAS that borrows ideas from consensus and game theory frameworks. Experimental results show that the proposed distributed approach provides significant improvements in terms of viewer experience, presentation quality stability, fairness and network utilization, without using any explicit communication between the players.

Bio: Abdelhak Bentaleb is a PhD candidate in Computer Science at School of Computing, National University of Singapore (NUS). He is advised by Prof. Roger Zimmermann and his work interest is on Video Streaming Architecture, Content Delivery, Multimedia Systems, and Computer Networks. He is a member of Media Management Research Lab and working on Streaming Media project. He designed and developed a novel suite of Adaptive Bitrate (ABR) solutions to address the key challenges of video delivery including quality instability, unfairness, and network resources under/over utilization for HTTP Adaptive Streaming (HAS) and HAS-like (DASH) systems.