Feedback control is increasingly being applied in server systems to make them more robust and efficient. This includes managing quality of service, minimizing power consumption, and adapting to varying workloads. Successful adaptation and control in turn relies on accurate tracking of workload variations and timely detection of changes in the computing infrastructure. Given that server systems are inherently event based, it is natural to consider event-based control and estimation schemes for them. As a prototypical problem, we study a single server system with time-varying arrival rate and derive optimal switching rules for the service rate. The goal is to keep the response time within bounds while minimizing the energy consumption of the server. We also design an event-based estimator of the server states based using a particle filter approach. Finally, we outline some of the broader research challenges related to event-based control and information fusion in server systems.
Anton Cervin received his Master's degree in Computer Science and Engineering in 1998 and his PhD degree in Automatic Control in 2003, both from Lund University, Sweden. Since 2007 he is an Associate Professor at the Department of Automatic Control at Lund University. Between 2012 and 2014 he was on leave to work in industry as a control engineering consultant.
Anton Cervin has broad research interests in analysis, simulation, design, and implementation of cyber-physical systems. He has done research in event-based and networked control, real-time scheduling and cloud control, and he has developed two popular tools for analysis and simulation of controller timing (Jitterbug and TrueTime). Recently, he is exploring event-based control and estimation of cloud server systems and currently has two PhD students working in that area.
Whatever the systems - large, small, embedded, autonomous… - filters are widely spread and very often mandatory building blocks. However, with the advent of autonomous systems supplied by batteries or harvesters and the popular Internet of Things (IoT) appeared strong power requirements. In order to circumvent this problem, reducing the amount of processed data appears as a good strategy. Indeed, digital equipment already exchange huge data flows and the future promises even more data and extra communications between humans and technological equipment such as robots, cars, planes, etc. Even if there already exists design solutions to enhance the energetic performances of the electronic filters and systems, non-uniform and sparse sampling appears as a relevant solution to drastically reduce the amount of useless data and to go beyond one order of magnitude in terms of power reduction. Indeed, having a reduced number of data limits the computation, the storage capacity, the communications and thus the power consumption. Such an analog-to- digital conversion requires specific skills when designing filters. This talk will present how to address the filter design and synthesis when a non-conventional sampling is applied. This will be illustrated by filter design examples based on level-crossing sampling schemes. Finally, as such sampling techniques are well-suited and compliant with asynchronous logic, some guidelines will be presented for implementing a fully event-driven filter circuit.
Laurent Fesquet (IEEE M’99, S’09), received the Ph.D. degree in electrical engineering from Paul Sabatier University, Toulouse, France, in 1997. In 1995, he was a Lecturer in charge of electronics and inertial navigation systems with the French Navy Instruction Center. In 1999, he joined the Grenoble Institute of Technology, Grenoble, France, as an Associate Professor. Since 2008, he has been Deputy Director of CIME Nanotech, an academic center that supports microelectronic teaching and research activities. His research, initially focused on asynchronous circuit design, has been extended in 2000 to non-uniform sampling techniques in order to enhance the analog-to- digital conversion. Since, he has been general chair in 2009 and program chair in 2011 and 2013 of the Sampling Theory and applications conference (SampTA). He has also been the program chair of the two first editions of the Event-based Control, Communication and Signal Processing conference (EBCCSP). His current research at the TIMA Laboratory today covers asynchronous circuit design, computer-aided design (CAD) for event-based systems and non-uniform signal processing. He is currently an invited professor at EPFL in Switzerland.
Marcelo Masera is Head of the Unit “Energy Security, Distribution and Markets” at the Directorate “Energy, Transportation and Climate” of the Joint Research Centre of the European Commission.
He studied Electronics and Electricity Engineering. Between 1981 and 1989 he was grantholder and research of CONICET (Argentina’s National Scientific and Technological Research Council). His research work was centred on reliability and risk of complex engineering systems. He was visiting scientist at the Joint Research Centre between 1990 and 1992, working on the assessment of industrial risk.
Between 1992 and 2000 he acted as private consulting, mainly working in research and development projects for petrochemical and other engineering companies. Since 2000 he is officer of the European Commission, working at the Joint Research Centre. Between 2000 and 2010 he was responsible for the group dealing with Critical Infrastructure Protection, theory of failures in cyber-physical systems and cybersecurity related aspects. Since 2011 he is Head of Unit responsible for security of supply, energy infrastructure and energy markets, based at the JRC site in Petten, the Netherlands.
Thierry Talbert, received the Ph.D. degree in electrical engineering from Sciences et Techniques du Languedoc University, Montpellier, France, in 2001. In 2002, he was working for Intelligent Electronics System for the development of a fan-less charger for Fenwick. In 2003, he was working for APEX-BP Solar division of British Petroleum for the development of autonomous inverter for African countries. In 2003, he joined the Laboratoire de Physique Appliquée et d'Automatique (LP2A), Perpignan Via Domitia University, Perpignan, France, as an Associate Professor. In 2011, LP2A laboratory join the PROMES-CNRS laboratory. In 2017, the Supervision, Solar Energy, Electrical System team (SEnSE) is created and takes the lead. After working on electromagnetic behavior and reliability of capacitors in power electronics, his current research covers development of DC/DC converters for concentrated cell (CPV) under 1000 suns and energy management of micro-grids (resource forecasting, V2G, distributed storage, modeling of power plant ...).