Speaker: Paolo Scarabaggio (Politecnico di Bari)
Title: Seeking Nash Equilibria under Nonconvex Coupling Constraints
Abstract: In noncooperative games, a number of self-interested agents with individual dynamics and constraints aim at optimizing their objective functions, possibly in competition with each other, e.g. due to the scarcity of shared resources. Nash games represent the common way to define the solution of these games in many practical applications, from electricity markets to mobile-edge computing. From a control-theoretic perspective, the objective is to develop a coordination mechanism, namely, a discrete-time dynamical system for updating the strategies of the agents towards an equilibrium. This talk will focus on a class of Nash games with nonconvex coupling constraints where a novel notion of local equilibrium is defined leveraging on the theory of tangent cones. The stability properties of these equilibria as well as the conditions for their existence and uniqueness are presented and discussed. Two discrete-time distributed dynamics or fixed-point iterations are proposed to compute these equilibria, while the convergence is show under (strongly) monotone assumptions on the pseudo-gradient mapping of the game. Applications to energy demand management under power flow constraints are shown.
Bio: Paolo Scarabaggio received the B.Sc. degree in Mechanical Engineering, the M.Sc. degree in Management Engineering, and the Ph.D. in Electrical and Information Engineering from Politecnico di Bari, Italy, in 2017, 2019, and 2022, respectively. He is currently a researcher at the Decision and Control Laboratory of Politecnico di Bari (http://dclab.poliba.it/). In 2019, he was a visiting student at the Delft Center for Systems and Control, Technical University of Delft, The Netherlands. His research interests include modeling, optimization, game theory, and control of complex multi-agent systems, with application in energy distribution systems, and social networks. He is author of 20+ printed international publications. He is the recipient of the 2022 IEEE CSS Italy Best Young Author Journal Paper Award.
When: Thrusday February 23rd from 3 pm to 4 pm
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Speaker: Giulia Giordano (Università di Trento)
Title: What we can learn from the system structure in biology and epidemiology
Abstract: Biological, ecological and epidemiological systems can be seen as dynamical networks, namely dynamical systems that are naturally endowed with an underlying network structure, because they are composed of several subsystems that interact according to an interconnection topology. Despite their large scale and complexity, natural systems often exhibit an extraordinary robustness that preserves fundamental properties and qualitative behaviours even in the presence of huge parameter variations and environmental fluctuations.
First, we focus on biochemical reaction networks and look for the source of the amazing robustness that often characterises them, by identifying properties and emerging behaviours that exclusively depend on the system structure (the graph topology along with qualitative information), regardless of parameter values. We introduce the BDC-decomposition to capture the system structure and enable the parameter-free assessment of important properties, including the stability of equilibria and the sign of steady-state input-output influences, thus allowing structural model falsification and structural comparison of alternative mechanisms proposed to explain the same phenomenon.
Then, inspired by the COVID-19 pandemic and the observation that compartmental models for epidemics can be seen as a special class of chemical reaction networks, we consider epidemiological systems describing the spread of infectious diseases within a population, along with control approaches to curb the contagion: we illustrate strategies to cope with the deep uncertainty affecting parameter values and optimally control the epidemic.
Bio: Giulia Giordano received the B.Sc. and M.Sc. degrees in electrical engineering and the Ph.D. degree in systems and control theory from the University of Udine, Italy, in 2010, 2012, and 2016, respectively. She visited the Control and Dynamical Systems Group, California Institute of Technology, Pasadena, CA, USA, in 2012, and the Institute of Systems Theory and Automatic Control, University of Stuttgart, Germany, in 2015. She was a Research Fellow with the LCCC Linnaeus Center and the Department of Automatic Control, Lund University, Sweden, from 2016 to 2017, and an Assistant Professor with the Delft Center for Systems and Control, Delft University of Technology, The Netherlands, from 2017 to 2019; she is currently with the Department of Industrial Engineering, University of Trento, Italy. She has been an Associate Editor for the IEEE Control Systems Letters since 2020 and for Automatica since 2022. She was recognised with the Outstanding Reviewer Letter from the IEEE Transactions on Automatic Control in 2016 and from the Annals of Internal Medicine in 2020, and chosen as Outstanding Associate Editor of the IEEE Control Systems Letters for the year 2021. She received the EECI Ph.D. Award 2016 from the European Embedded Control Institute, the NAHS Best Paper Prize 2017, and the SIAM Activity Group on Control and Systems Theory Prize 2021. Her main research interests include the analysis and the control of dynamical networks, with applications especially to biology and epidemiology.
When: Monday November 7th 2022 from 11 am to 12 am
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Speaker: Karen Rudie (Queen’s University, Canada)
Title: How Discrete-Event Systems Can Keep Secrets Secret
Abstract: The control theory of discrete-event systems (DESs) is a modeling framework for capturing the ordering of events or actions. Discrete-event systems modeling can be complementary to traditional continuous-time systems modeling or can be used alongside or in concert with continuous-time modeling in hybrid systems. Since decision-making is tantamount to prescribing which actions should or should not happen or which actions should happen before others, the body of work in DES theory is well-positioned to allow us to tackle security problems in cyber-physical systems. In this talk we present different approaches in DES control theory that address various problems in the security of systems and networks. In particular, we examine the notion of opacity, which is the property of ensuring that secret states or secret sequences of events are not discernible from non-secret states or events to a hostile agent. We also look at cases where systems are attacked by adversarial agents that manipulate sensor outputs (i.e., event occurrences generated by a plant) so that a supervisor (i.e., a DES controller) is fooled into thinking the system is in some state that it is not in. We discuss the challenges of modeling security and secrecy problems using discrete-event systems.
Bio: Karen Rudie is a Professor at Queen’s University (Canada) in the Department of Electrical and Computer Engineering, with a cross-appointment to the School of Computing. She received her Ph.D. in 1992 from the University of Toronto, in the Systems Control Group, under the supervision of W. Murray Wonham. In 1992-93 she was a postdoctoral researcher at the Institute for Mathematics and its Applications, Minnesota. From 2004-2006 she was an IEEE Control Systems Society Distinguished Lecturer. She has served on the editorial board of the Journal of Discrete Event Dynamic Systems (since 2000), where she is currently a Department Editor, and has served as an Associate Editor for IEEE Transactions on Control Systems Technology (2015-2020), IEEE Transactions on Automatic Control (1996-1999), and IEEE Control Systems Magazine (2003). She is a Fellow of the IEEE. Her research focuses on the control of discrete-event systems.
When: Wednesday May 18th 2022 from 4 pm to 5 pm
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Speaker: Mattia Bianchi (TU Delft, The Netherlands)
Title: Generalized Nash equilibrium problems over networks
Abstract: In recent years, the need has emerged to control large networks of interacting systems to allow for their safe and effective operation, for instance in power distribution, traffic regulation and communication infrastructures. Hand in hand with distributed optimization, Nash games provide powerful tools to ensure coordination, namely the attainment of a desirable equilibrium, especially in the presence of self-interested agents. In this talk we focus on Nash equilibrium seeking under partial-decision information, where each agent can only observe the decisions of some neighbors over a communication network, while its cost function possibly depends on the actions of all the competitors. For this relatively novel scenario, we discuss the limitations of the existing methods, and we propose more efficient algorithms.
Bio: Mattia Bianchi is a Ph.D. candidate in the Delft Center for Systems and Control, TU Delft (NL). He received the Bachelor’s degree in Information Engineering and the Master’s degree in Control Systems Engineering, both from University of L’Aquila (IT), in 2016 and 2018, respectively. In 2018 he visited the Control Systems Technology group, TU Eindhoven (NL). In 2021-2022 he visited the Mechanical and Aerospace Engineering Department, University of California San Diego (USA). His research interests include game theory and operator theory to solve decision and control problems for complex systems of systems, in the presence of network coupling and uncertainty. He is recipient of the 2021 Roberto Tempo Best Paper Award at the IEEE Conference on Decision and Control.
When: Friday March 25th 2022 from 15.00 to 16.00
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Speaker: Prof. Maide Bucolo (University of Catania - Italy)
Title: Control Engineering in Two-Phase Microfluidics for Bio-Chemical Applications
Abstract: The current microfluidic technology allows the reproduction into a single chip of many functionalities of a macro-scale bio-chemical laboratory. Generally the micro-channels dimension is in the range between ten to hundreds micrometer up to one millimeter. Moving from smaller to larger microchannels, on one side speeds-up the process, making it suitable for industrial applications, but on the other side the process evolves in a transition zone between the linear and nonlinear behavior. In our studies we have investigated two-phase microfluidics, generated both by immiscible fluid-fluid interaction (slug flow regime) and micro-particles suspension in a fluid, in irregular micro-channels with diameter greater than hundreds micrometer. In this complex scenario in which the properties of the fluids, the input flow conditions, the channel geometries and the material surface properties can strongly affect the flow dynamics, a data-driven approach for the processes identification and control based on optical technology has been chosen for its potential impact in design of smart micro-optofluidics embedded systems. Managing optical images and signals offers the advantages of being noninvasive and easily embedded in portable devices for real-time applications, but requires an accurate data analysis and interpretation. It Thanks to advanced modeling and control strategies, two platforms have been developed one for the real-time slug flow tracking and the other for the process control. This has been a fundamental step in the design and realization of embedded micro-optofluidic PDMS devices. Different micro-devices will be presented used in both cell flow and slug flow investigations: micro-optical interfaces, realized by soft-lithography and, micro-optofluidics embedded devices realized by 3D printing. The combination between the technological advancement of the 3D printing and the potentiality of a control methodological framework brings a drastic reduction of the cost and the complexity in the micro-optofluidics devices fabrication and experimental set-up, extending their use as a new generation of disposable and portable devices for bio-chemical analyses, easy-to use and widely accessible.
Bio: Maide Bucolo received the M.S. degree in Computer Science Engineering in 1997, and the Ph.D in Electronic and Control Engineering in 2001 from the University of Catania. During the Ph.D. she worked as research scholar at the University of California San Diego (UCSD) and after that, often, she has been hosted as visiting researcher and professor at the Microhemodynamics Lab of the Department of Bioengineering at UCSD. She is currently Associate Professor in Control System at the Department of Electrical, Electronic and Informatics of the University of Catania. Since 2018 she is coordinator of the MSc in Automation Engineering and Control of Complex Systems at the University of Catania. Her research is focused on methodologies and low-cost technologies for bio-microfluidics systems modeling and control. In 2010 she established and became responsible of the 'Bio-Microfluidics Laboratory" at the University of Catania. In the field of Micro-systems Engineering she was visiting professor at the Heriot Watt University and at the Institut National des Sciences Appliquées (INSA) de Toulouse. She has been the coordinator of national projects and international exchange programs. She is IEEE senior member. She has published more than 100 scientific contributions in peer-reviewed International Journals and Conferences
When: Thursday February 3rd 2022 from 10.30 to 11.30
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Speaker: Dr. Catia Trubiani (Gran Sasso Science Institute, L’Aquila - Italy)
Title: Cyber Physical Systems: a software quality perspective on uncertainties
Abstract: Cyber-physical systems are exposed to multiple uncertainties due to mixing software and hardware components that operate in complex and changing environments. Uncertainty can be critical for software quality, especially in the presence of highly dynamic changes, for instance when alterations in the physical space affect the capability of a swarm of robots to complete a task on time. Incorporating uncertainty as a first-class concept in the software development process to identify quality issues is still challenging. This talk presents two ways of handling uncertainty: (i) performance models capturing how different architectural patterns affect the performance characteristics of the evolving physical space; (ii) uncertainty-aware testing strategies to drive the test case generation process. A goal of this research is to provide quantitative evaluation that supports system stakeholders in the identification of software quality issues.
Bio: Catia Trubiani is Assistant Professor at the Gran Sasso Science Institute (GSSI), Italy. Previously she collaborated with various international research institutes like the Karlsruhe Institute of Technology in Germany, and the Imperial College of London in UK. She is principal investigator of the GSSI unit for the MUR-PRIN project SEDUCE (Young Line action) and for the MUR-FISR project MVM-Adapt. In 2021 she received the Exceptional Reviewer Award for the International Conference on Software Architecture (ICSA), and the 10-year most influential paper for the International Conference on Performance Engineering (ICPE). More information is available here: http://cs.gssi.it/catia.trubiani
When: Monday November 22nd 2021 from 15.00 to 16.00
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Speaker: Prof. Romain Postoyan (CNRS, CRAN, Université de Lorraine - France)
Title: Dynamical systems controlled by value iteration: stability, near-optimality and stopping criterion
Abstract: Value iteration (VI) is a ubiquitous algorithm for optimal control, planning, and reinforcement learning schemes. Under the right assumptions, VI is a vital tool to generate inputs with optimal properties for general nonlinear systems and cost functions. However, several important questions remain largely unexplored in the literature in particular: what can we say about the stability of systems whose inputs are obtained by VI? and what about their robustness properties? These properties are fundamental in numerous safety-critical control applications, it is thus of primary importance to make sure that the use of VI to construct the control inputs is done in such a way that robust stability of the closed-loop system is ensured. In this talk, we will provide answer to these questions for the case where the plant dynamics is known, deterministic nonlinear and in discrete-time. We will then see how stability can be exploited to significantly improve existing near-optimality bounds of the literature, i.e., the mismatch between the value function given by VI at each step and the targeted optimal value function. We will also provide some first elements on when to rigorously stop the algorithm and how to implement it.
When: Wednesday July 14th 2021 from 11.00 to 12.00
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Speaker: Prof. Pasquale Palumbo (University of Milano-Bicocca, Italy)
Title: A mathematical model of the G1/S transition for the budding yeast
Abstract: In budding yeast, overcoming of a critical size to enter S phase and the mitosis/mating switch—two central cell fate events—take place in the G1 phase of the cell cycle. Here we present a mathematical model of the basic molecular mechanism controlling the G1/S transition, whose major regulatory feature is multisite phosphorylation of nuclear Whi5. Cln3–Cdk1, whose nuclear amount is proportional to cell size, and then Cln1,2–Cdk1, randomly phosphorylate both decoy and functional Whi5 sites. Full phosphorylation of functional sites releases Whi5 inhibitory activity, activating G1/S transcription. Simulation analysis shows that this mechanism ensures coherent release of Whi5 inhibitory action and accounts for many experimentally observed properties of mitotically growing or conjugating G1 cells. Cell cycle progression and transcriptional analyses of a Whi5 phosphomimetic mutant verify the model prediction that coherent transcription of the G1/S regulon and ensuing G1/S transition requires full phosphorylation of Whi5 functional sites
When: Monday June 28th 2021 from 14.30 to 15.30
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Speaker: Dr. Mirco Giacobbe (University of Oxford, UK)
Title: Neuro-symbolic Liveness Verification
Abstract: Liveness verification answers the question of whether a system always responds with desirable behavior or, dually, never gets stuck without responding at all. For dynamical systems, this relates to the stability question; for computer programs, it relates to the halting problem. I will talk about a novel method for constructing liveness proofs by learning witnesses (Lyapunov and ranking functions) from data using neural networks combined with symbolic reasoning. I will talk about how we apply this neuro-symbolic approach to the stability analysis of dynamical systems, to the termination analysis of Java programs, and to the almost-sure termination analysis of probabilistic programs.
When: Friday June 11th 2021 from 14.30 to 15.30
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