{"title":"We Are Legion: High Probability Regret Bound in Adversarial Multiagent Online Learning","authors":"Sri Jaladi;Ilai Bistritz","doi":"10.1109/LCSYS.2024.3519637","DOIUrl":"https://doi.org/10.1109/LCSYS.2024.3519637","url":null,"abstract":"We study a large-scale multiagent online learning problem where the number of agents N is significantly larger than the number of arms K. The agents face the same adversarial online learning problem with K arms over T rounds, where the adversary chooses the cost vectors <inline-formula> <tex-math>$boldsymbol {l}(1), ldots ,boldsymbol {l}(T)$ </tex-math></inline-formula> before the game begins. Each round t, each agent n picks an arm <inline-formula> <tex-math>$a_{n}$ </tex-math></inline-formula>(t) and incurs a cost of <inline-formula> <tex-math>$l_{a_{n}(t)}$ </tex-math></inline-formula> (t). Then, at the end of the round, all agents observe the costs of all arms <inline-formula> <tex-math>$l_{1}(t), ldots ,l_{K}(t)$ </tex-math></inline-formula>. The exponential weights algorithm achieves an order-wise optimal expected regret of <inline-formula> <tex-math>$O(sqrt {T})$ </tex-math></inline-formula> for each agent. However, the variance of the sum of regrets scales linearly with the number of agents, which is unacceptable for a large-scale multi-agent system. To mitigate this, we propose a simple fully distributed algorithm that achieves the same optimal expected sum of regrets but reduces the variance of the sum of regrets from O(N) to <inline-formula> <tex-math>$O(min (N,K))$ </tex-math></inline-formula> with no communication required between the agents.","PeriodicalId":37235,"journal":{"name":"IEEE Control Systems Letters","volume":"8 ","pages":"2985-2990"},"PeriodicalIF":2.4,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142975927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Fast-and-Flexible Decision-Making With Modulatory Interactions","authors":"Rodrigo Moreno-Morton;Anastasia Bizyaeva;Naomi Ehrich Leonard;Alessio Franci","doi":"10.1109/LCSYS.2024.3519445","DOIUrl":"https://doi.org/10.1109/LCSYS.2024.3519445","url":null,"abstract":"Multi-agent systems in biology, society, and engineering are capable of making decisions through the dynamic interaction of their elements. Nonlinearity of the interactions is key for the speed, robustness, and flexibility of multi-agent decision-making. In this work we introduce modulatory, that is, multiplicative, in contrast to additive, interactions in a nonlinear opinion dynamics model of fast-and-flexible decision-making. The original model is nonlinear because network interactions, although additive, are saturated. Modulatory interactions introduce an extra source of nonlinearity that greatly enriches the model’s decision-making behavior in a mathematically tractable way. Modulatory interactions are widespread in both biological and social decision-making networks; our model provides new tools to understand the role of these interactions in networked decision-making and to engineer them in artificial systems.","PeriodicalId":37235,"journal":{"name":"IEEE Control Systems Letters","volume":"8 ","pages":"3333-3338"},"PeriodicalIF":2.4,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143184272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Data-Driven Predictive Control of Bilinear HVAC Dynamics—An Experimental Case Study","authors":"Deborah Bilgic;Alexander Harding;Timm Faulwasser","doi":"10.1109/LCSYS.2024.3519224","DOIUrl":"https://doi.org/10.1109/LCSYS.2024.3519224","url":null,"abstract":"Buildings are responsible for around 40% of the global energy demand. In order to effectively reduce the high energy consumption of HVAC systems while maintaining comfortable indoor climate, tailored control schemes are promising. Since the derivation of physical models of individual HVAC systems is time consuming, data-driven methods are a promising alternative. This letter proposes a framework for data-driven predictive control of HVAC system with bilinear system dynamics, which compensates for prediction errors via constraint adaptation through a bias term. The proposed scheme combines an extension of Willems’ fundamental lemma to bilinear systems with the consideration of multiple data-sets. To evaluate the efficacy of the data-driven control scheme, an experimental case study is performed under realistic conditions. In comparison with an existing simple control scheme, our results demonstrate energy efficient operation and successful compensation of prediction errors.","PeriodicalId":37235,"journal":{"name":"IEEE Control Systems Letters","volume":"8 ","pages":"3009-3014"},"PeriodicalIF":2.4,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142912383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Adversarial Sensor Attacks Against Uncertain Cyber-Physical Systems: A Dynamic Output Feedback Approach","authors":"Kartik A. Pant;Shiraz Khan;Inseok Hwang","doi":"10.1109/LCSYS.2024.3519435","DOIUrl":"https://doi.org/10.1109/LCSYS.2024.3519435","url":null,"abstract":"The design of sensor spoofing attacks for cyber-physical systems (CPSs) has received considerable attention in the literature, as it can reveal the underlying vulnerabilities of the CPS. We present a dynamic output feedback approach for designing stealthy sensor spoofing attacks against CPSs. Unlike the existing works, we consider the case where the attacker has limited knowledge of the victim CPS’s dynamical model, characterized by polytopic uncertainty. It is shown that despite the limited knowledge of the attacker, the proposed stealthy sensor spoofing attack method can provably avoid detection by the onboard detection mechanism, even in the presence of model uncertainties, measurement noises, and disturbances. Furthermore, we show that the resulting attack design is recursively feasible, i.e., the designed attack at the current time step ensures persistent detection constraint satisfaction throughout the attack. Finally, we demonstrate the effectiveness of our approach through an illustrative numerical simulation of a sensor spoofing attack on a quadrotor.","PeriodicalId":37235,"journal":{"name":"IEEE Control Systems Letters","volume":"8 ","pages":"2997-3002"},"PeriodicalIF":2.4,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142962892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mikihisa Yuasa;Huy T. Tran;Ramavarapu S. Sreenivas
{"title":"On Generating Explanations for Reinforcement Learning Policies: An Empirical Study","authors":"Mikihisa Yuasa;Huy T. Tran;Ramavarapu S. Sreenivas","doi":"10.1109/LCSYS.2024.3519301","DOIUrl":"https://doi.org/10.1109/LCSYS.2024.3519301","url":null,"abstract":"Explaining reinforcement learning policies is important for deploying them in real-world scenarios. We introduce a set of linear temporal logic formulae designed to provide such explanations, and an algorithm for searching through those formulae for the one that best explains a given policy. Our key idea is to compare action distributions from the target policy with those from policies optimized for candidate explanations. This comparison provides more insight into the target policy than existing methods and avoids inference of “catch-all” explanations. We demonstrate our method in a simulated game of capture-the-flag, a car-parking environment, and a robot navigation task.","PeriodicalId":37235,"journal":{"name":"IEEE Control Systems Letters","volume":"8 ","pages":"3027-3032"},"PeriodicalIF":2.4,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142962832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ahmet Kaan Aydin;Md Zulfiqur Haider;Ahmet Özkan Özer
{"title":"A New Semi-Discretization of the Fully Clamped Euler-Bernoulli Beam Preserving Boundary Observability Uniformly","authors":"Ahmet Kaan Aydin;Md Zulfiqur Haider;Ahmet Özkan Özer","doi":"10.1109/LCSYS.2024.3519379","DOIUrl":"https://doi.org/10.1109/LCSYS.2024.3519379","url":null,"abstract":"This letter extends a Finite Difference model reduction method to the Euler-Bernoulli beam equation with fully clamped boundary conditions. The corresponding partial differential equation (PDE) is exactly observable in the energy space with a single boundary observer in arbitrarily short observation times. However, standard Finite Difference spatial discretization fails to achieve uniform exact observability as the mesh parameter approaches zero, with minimal observation time potentially depending on the filtering parameter. To address this, we propose a Finite Difference algorithm incorporating an averaging operator and discrete multipliers, leveraging Haraux’s theorem on the spectral gap to ensure uniform observability. This approach eliminates the need for artificial viscosity or Fourier filtering. Our method achieves uniform observability for arbitrarily small times with dual observers-the tip moment and average tip velocity-mirroring results from mixed Finite Elements applied to the wave equation with homogeneous Dirichlet boundary conditions, where dual controllers converge to the single controller of the PDE model [Castro, Micu-Numerische Mathematik’06]. Our reduced model is applicable to more complex systems involving Euler-Bernoulli beam equations.","PeriodicalId":37235,"journal":{"name":"IEEE Control Systems Letters","volume":"8 ","pages":"2955-2960"},"PeriodicalIF":2.4,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142975846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"On the O(1/k) Convergence of Distributed Gradient Methods Under Random Quantization","authors":"Amit Dutta;Thinh T. Doan","doi":"10.1109/LCSYS.2024.3519013","DOIUrl":"https://doi.org/10.1109/LCSYS.2024.3519013","url":null,"abstract":"We revisit the so-called distributed two-time-scale stochastic gradient method for solving a strongly convex optimization problem over a network of agents in a bandwidth-limited regime. In this setting, the agents can only exchange the quantized values of their local variables using a limited number of communication bits. Due to quantization errors, the existing best-known convergence results of this method can only achieve a suboptimal rate <inline-formula> <tex-math>$mathcal {O}$ </tex-math></inline-formula>(<inline-formula> <tex-math>$1/sqrt {k}$ </tex-math></inline-formula>), while the optimal rate is <inline-formula> <tex-math>$mathcal {O}$ </tex-math></inline-formula>(<inline-formula> <tex-math>$1/k$ </tex-math></inline-formula>) under no quantization, where k is the time iteration. The main contribution of this letter is to address this theoretical gap, where we study a sufficient condition and develop an innovative analysis and step-size selection to achieve the optimal convergence rate <inline-formula> <tex-math>$mathcal {O}$ </tex-math></inline-formula>(<inline-formula> <tex-math>$1/k$ </tex-math></inline-formula>) for the distributed gradient methods given any number of quantization bits. We provide numerical simulations to illustrate the effectiveness of our theoretical results.","PeriodicalId":37235,"journal":{"name":"IEEE Control Systems Letters","volume":"8 ","pages":"2967-2972"},"PeriodicalIF":2.4,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142975932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"From a Single Trajectory to Safety Controller Synthesis of Discrete-Time Nonlinear Polynomial Systems","authors":"Behrad Samari;Omid Akbarzadeh;Mahdieh Zaker;Abolfazl Lavaei","doi":"10.1109/LCSYS.2024.3519017","DOIUrl":"https://doi.org/10.1109/LCSYS.2024.3519017","url":null,"abstract":"This letter is concerned with developing a data-driven approach for learning control barrier certificates (CBCs) and associated safety controllers for discrete-time input-affine nonlinear systems with polynomial dynamics with (partially) unknown mathematical models, guaranteeing system safety over an infinite time horizon. The proposed approach leverages measured data acquired through an input-state observation, referred to as a single trajectory, collected over a specified time horizon. By fulfilling a certain rank condition, which ensures the unknown system is persistently excited by the collected data, we design a CBC and its corresponding safety controller directly from the finite-length observed data, without explicitly identifying the unknown dynamical system. This is achieved through proposing a data-based sum-of-squares optimization (SOS) program to systematically design CBCs and their safety controllers. We validate our data-driven approach over two physical case studies including a jet engine and a Lorenz system, demonstrating the efficacy of our proposed method.","PeriodicalId":37235,"journal":{"name":"IEEE Control Systems Letters","volume":"8 ","pages":"3123-3128"},"PeriodicalIF":2.4,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142962890","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Finite-Dimensional Observer-Based Boundary Control of 1-D Linear Parabolic-Elliptic Systems","authors":"Pengfei Wang;Emilia Fridman","doi":"10.1109/LCSYS.2024.3518396","DOIUrl":"https://doi.org/10.1109/LCSYS.2024.3518396","url":null,"abstract":"This letter investigates the finite-dimensional observer-based boundary control for 1D linear parabolic-elliptic systems via the modal decomposition method. To address the potential multiple eigenvalues arising from the elliptic equation, we implement bilateral actuations (one Dirichlet and one Neumann) on the boundary of the parabolic equation with two point measurements. When the eigenvalues are simple, one boundary actuation and one point measurement are sufficient, but the second input and output may reduce the observer dimension. We present efficient LMI conditions for finding observer dimension, as well as controller and observer gains, ensuring the <inline-formula> <tex-math>${mathrm { H}}^{1}$ </tex-math></inline-formula> exponential stability with any desirable decay rate. We show that the LMIs are always feasible for large enough values of the observer dimension. Numerical examples demonstrate the efficiency of the method.","PeriodicalId":37235,"journal":{"name":"IEEE Control Systems Letters","volume":"8 ","pages":"2943-2948"},"PeriodicalIF":2.4,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142975929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Investigating Bistable Dynamics of Coupled Oscillators With Similarities to Neural Activity in Epilepsy","authors":"Nilay Kant;Ranjan Mukherjee","doi":"10.1109/LCSYS.2024.3519014","DOIUrl":"https://doi.org/10.1109/LCSYS.2024.3519014","url":null,"abstract":"The dynamics of an oscillator, which exhibits a stable equilibrium and a stable limit cycle, is investigated. We refer to it as a bistable oscillator unit (BOU) and show that two coupled BOUs (CBOUs) exhibit dynamics analogous to neural activity patterns in epilepsy, including healthy, localized, and fully spread epileptic states. By treating each CBOU as an independent system influenced by the state of the other, we establish local input-to-state stability near the equilibrium and the limit cycle, and estimate the ultimate bounds of the trajectories. Our analysis identifies the domain of the initial conditions and estimates the coupling parameter critical in determining the epileptic behavior of the CBOUs. The actual value of the coupling parameter, above which the dynamics transition from localized to fully spread epileptic states, is determined through simulations; the results closely match the derived analytical estimate.","PeriodicalId":37235,"journal":{"name":"IEEE Control Systems Letters","volume":"8 ","pages":"2919-2924"},"PeriodicalIF":2.4,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142976173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}