The main goal of the Aggreg project is to develop efficient algorithms for answering aggregate queries for databases and data streams of various kinds. Aggregate queries are central for computing statistics on data collections: Rdf stores, NoSql databases, streams of data trees in Xml or Json format, uncertain databases, relational databases, and datawarehouses. Considering that counting is the basis of aggregate queries the principal difficulty here is to overcome the inherent computational hardness of many counting problems, which precludes general and efficient solutions. Instead, we propose to: study the complexity of expressive fragments of the class of aggregate queries, search for efficient algorithms on tractable fragments, identify which parameters can be fixed in order to obtain tractability, find general algorithms that are gracefully degrading, and also efficient approximation algorithms. We apply methods from algebra, automata, probability, algorithmics and complexity theory.

The objectives of this project can be divided into two main parts: the first one concerns the design of new methodologies of high order and discrete-time sliding mode controllers, in order to reduce chattering and improve disturbance rejection. The efficiency of these novel algorithms will be evaluated thanks to their application to several electromechanical experimental set-ups which are available. The second aspect concerns the development of softwares dedicated to sliding mode control design: first of all, formal computation software, based on IRCCyN software NOLIACPA, will be developed allowing to formally compute the sliding mode control (SMC) solution for the uploaded system. Then, an efficient simulation tool using the INRIA/SICONOS library for the simulation of nonsmooth dynamical systems will be developed, in order to obtain a prototype toolbox for the design and the simulation of sliding-mode controllers. The second aspect will lead to the production of the very first free software especially dedicated to SMC. This project will be also the frame for the promotion of sliding-mode control theory through two major events: 1) International Workshop on Variable Structure Systems – IRCCyN will be candidate for the organisation of this major international event in 2014 (it will be the 13th workshop on this topic). The aim of this workshop is to bring together international researchers and practitionners interested in variable structure and sliding mode control. 2) International Summer School on Variable Structure and Sliding Mode Systems. The objective is to bring together Ph.D. students, faculty members, industry engineers, … and to expose not only fundamental notions of VSS/Sliding Mode Control, but also more recent results (as high order, adaptive, and discrete-time sliding mode controllers)), as well as labs on the SMC toolbox developed by the project.

The potential offered by the abundance of sensors, actuators and communications in IoT era is hindered by the limited computational capacity of local nodes, making the distribution of computing in time and space a necessity. Several key challenges need to be addressed in order to optimally and jointly exploit the network, computing, and storage resources, guaranteeing at the same time feasibility for time-critical and mission-critical tasks. Our research takes upon these challenges by dynamically distributing resources when the demand is rapidly time varying. We first propose an analytic mathematical dynamical modelling of the resources, offered workload, and networking environment, that incorporates phenomena met in wireless communications, mobile edge computing data centres, and network topologies. We also propose a new set of estimators for the workload and resources time-varying profiles that continuously update the model parameters. Building on this framework, we aim to develop novel resource allocation mechanisms that take explicitly into account service differentiation and context-awareness, and most importantly, provide formal guarantees for well-defined QoS/QoE metrics. Our research goes well beyond the state of the art also in the design of control algorithms for cyber-physical systems (CPS), by incorporating resource allocation mechanisms to the decision strategy itself. We propose a new generation of controllers, driven by a co-design philosophy both in the network and computing resources utilization. This paradigm has the potential to cause a quantum leap in crucial fields in engineering, e.g., Industry 4.0, collaborative robotics, logistics, multi-agent systems etc. To achieve these breakthroughs, we utilize and combine tools from Automata and Graph theory, Machine Learning, Modern Control Theory and Network Theory, fields where the consortium has internationally leading expertise. Although researchers from Computer and Network Science, Control Engineering and Applied Mathematics have proposed various approaches to tackle the above challenges, our research constitutes the first truly holistic, multidisciplinary approach that combines and extends recent, albeit fragmented results from all aforementioned fields, thus bridging the gap between efforts of different communities. Our developed theory will be extensively tested on available experimental testbed infrastructures of the participating entities. The efficiency of the overall proposed framework will be tested and evaluated under three complex use cases involving mobile autonomous agents in IoT environments: (i) distributed remote path planning of a group of mobile robots with complex specifications, (ii) rapid deployment of mobile agents for distributed computing purposes in disaster scenarios and (iii) mobility-aware resource allocation for crowded areas with pre-defined performance indicators to reach.