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Dependency Tasks Offloading and Communication Resource Allocation in Collaborative UAVs Networks: A Meta-Heuristic Approach

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arXiv 2022年

作者： Nguyen, Loc X. Tun, Yan Kyaw Dang, Tri Nguyen Park, Yu Min Han, Zhu Hong, Choong Seon The Department of Computer Science and Engineering Kyung Hee University Gyeonggi-do Yongin-si17104 Korea Republic of Division of Network and Systems Engineering School of Electrical Engineering and Computer Science KTH Royal Institute of Technology Brinellvägen 8 Stockholm114 28 Sweden The Electrical and Computer Engineering Department University of Houston HoustonTX77004 United States

In recent years, unmanned aerial vehicles (UAVs) assisted mobile edge computing systems have been exploited by researchers as a promising solution for providing computation services to mobile users outside of terrestrial infrastructure coverage. However, it remains challenging for the standalone MEC-enabled UAVs in order to meet the computation requirement of numerous mobile users due to the limited computation capacity of their onboard servers and battery lives. Therefore, we propose a collaborative scheme among UAVs so that UAVs can share the workload with idle UAVs. Moreover, current task offloading strategies frequently overlook task topology, which may result in poor performance or even system failure. To address the problem, we consider offloading tasks consisting of a set of subtasks, and each sub-task has dependencies on other sub-tasks, which is practical in the real world. Sub-tasks with dependencies need to wait for the resulting signal from preceding sub-tasks before being executed. This mechanism has serious effects on the offloading strategy. Then, we formulate an optimization problem to minimize the average latency experienced by users by jointly controlling the offloading decision for dependent tasks and allocating the communication resources of UAVs. The formulated problem appears to be NP-hard and cannot be solved in polynomial time. Therefore, we divide the problem into two sub-problems: the offloading decision problem and the communication resource allocation problem. Then a meta-heuristic method is proposed to find the sub-optimal solution of the task offloading problem, while the communication resource allocation problem is solved by using convex optimization. Finally, we perform substantial simulation experiments, and the result shows that the proposed offloading technique effectively minimizes the average latency of users, compared with other benchmark schemes. Copyright © 2022, The Authors. All rights reserved.

关键词： Convex optimization

Network topology detection via uncertainty analysis of an identified static model

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IFAC-PapersOnLine 2021年第7期54卷 595-600页

作者： X. Bombois H. Hjalmarsson Laboratoire Ampére Ecole Centrale de Lyon Université de Lyon Ecully France Centre National de la Recherche Scientifique (CNRS) France Centre for Advanced Bio Production and Division of Decision and Control Systems School of Electrical Engineering and Computer Science KTH Stockholm Sweden

In this paper, we propose a methodology to detect the topology of a dynamic network that is based on the analysis of the uncertainty of the static characteristic of the matrix of transfer functions between the externa... 详细信息

关键词： Dynamic network identification topology detection

Cooperative system identification via correctional learning

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arXiv 2020年

作者： Lourenço, Inês Mattila, Robert Rojas, Cristian R. Wahlberg, Bo Division of Decision and Control Systems School of Electrical Engineering and Computer Science KTH Royal Institute of Technology Stockholm Sweden

We consider a cooperative system identification scenario in which an expert agent (teacher) knows a correct, or at least a good, model of the system and aims to assist a learner-agent (student), but cannot directly transfer its knowledge to the student. For example, the teacher’s knowledge of the system might be abstract or the teacher and student might be employing different model classes, which renders the teacher’s parameters uninformative to the student. In this paper, we propose correctional learning as an approach to the above problem: Suppose that in order to assist the student, the teacher can intercept the observations collected from the system and modify them to maximize the amount of information the student receives about the system. We formulate a general solution as an optimization problem, which for a multinomial system instantiates itself as an integer program. Furthermore, we obtain finite-sample results on the improvement that the assistance from the teacher results in (as measured by the reduction in the variance of the estimator) for a binomial system. In numerical experiments, we illustrate the proposed algorithms and verify the theoretical results that have been derived in the paper. Copyright © 2020, The Authors. All rights reserved.

关键词： Students

On the confidentiality of controller states under sensor attacks

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arXiv 2020年

作者： Umsonst, David Sandberg, Henrik Division of Decision and Control Systems School of Electrical Engineering and Computer Science KTH Royal Institute of Technology Stockholm Sweden

With the emergence of cyber-attacks on control systems it has become clear that improving the security of control systems is an important task in today's society. We investigate how an attacker that has access to the measurements transmitted from the plant to the controller can perfectly estimate the internal state of the controller. This attack on sensitive information of the control loop is, on the one hand, a violation of the privacy, and, on the other hand, a violation of the security of the closed-loop system if the obtained estimate is used in a larger attack scheme. Current literature on sensor attacks often assumes that the attacker has already access to the controller's state. However, this is not always possible. We derive conditions for when the attacker is able to perfectly estimate the controller's state. These conditions show that if the controller has unstable poles a perfect estimate of the controller state is not possible. Moreover, we propose a defence mechanism to render the attack infeasible. This defence is based on adding uncertainty to the controller dynamics. We also discuss why an unstable controller is only a good defence for certain plants. Finally, simulations with a three-tank system verify our results. Copyright © 2020, The Authors. All rights reserved.

关键词： Linear control systems

Actuator Security Index for Structured systems

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Actuator Security Index for Structured Systems

American control Conference

作者： Sebin Gracy Jezdimir Milosevic Henrik Sandberg Division of Decision and Control Systems School of Electrical Engineering and Computer Science KTH Royal Institute of Technology Stockholm Sweden

ISBN: (数字)9781538682661

ISBN: (纸本)9781538682678

Given a network with a set of vulnerable actuators (and sensors), the security index of an actuator equals the minimum number of sensors and actuators that needs to be compromised so as to conduct a perfectly undetectable attack using the said actuator. This paper deals with the problem of computing actuator security indices for discrete-time LTI network systems, using a structured systems framework. We show that the actuator security index is generic, that is for almost all realizations the actuator security index remains the same. We refer to such an index as generic security index (generic index) of an actuator. Given that the security index quantifies the vulnerability of a network, the generic index is quite valuable for large scale energy systems. Our second contribution is to provide graph-theoretic conditions for computing the generic index. The said conditions are in terms of existence of linkings on appropriately-defined directed (sub)graphs. Based on these conditions, we present an algorithm for computing the generic index.

关键词： actuators Indexes Security

Finite-time consensus protocols for multi-dimensional multi-agent systems

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control Theory and Technology 2020年第4期18卷 419-430页

作者： Jieqiang Wei Bart Besselink Junfeng Wu Henrik Sandberg Karl H.Johansson Ericsson Global AI Accelerator Torshamnsgatan 21StockholmSweden Bernoulli Institute for Mathematics Computer Science and Artificial IntelligenceUniversity of GroningenP.O.Box 4079700 GroningenAKThe Netherlands College of Control Science and Engineering Zhejiang University310027 HangzhouChina Division of Decision and Control Systems KTH Royal Institute of Technology10044 StockholmSweden

A fnite.-time consensus protocol is proposed for multi -dimensional multi- agent systems, using direction peserving signumcontrols. Flipp solutions and nonsmooh analysis tehniques are adopted to handle discontinuities. Suficient and ncessaryconditions are provided to guarantee infinte time convergence and boundedness of the solutions. It turns out that the numberof agents which have cotinuous contol law plays an ssenan role in fnite-tine conerence In adidio it is shown thatthe unit bals itoduced bylp, norms. where p ∈[1,∞] , are inariat for the closed lop.

关键词： Multi-agent systems Network consensus Finite time convergence Nonsmooth analysis

Compositional Synthesis of Signal Temporal Logic Tasks via Assume-Guarantee Contracts

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arXiv 2022年

作者： Liu, Siyuan Saoud, Adnane Jagtap, Pushpak Dimarogonas, Dimos V. Zamani, Majid Department of Electrical and Computer Engineering Technical University of Munich Germany Computer Science Department LMU Munich Germany Laboratoire des Signaux et Systèmes CentraleSupélec Univ. Paris Saclay Gif sur Yvette France Robert Bosch Center for Cyber-Physical Systems in Indian Institute of Science Bangalore India Division of Decision and Control Systems KTH Royal Institute of Technology Stockholm Sweden Computer Science Department University of Colorado Boulder United States

In this paper, we focus on the problem of compositional synthesis of controllers enforcing signal temporal logic (STL) tasks over a class of continuous-time nonlinear interconnected systems. By leveraging the idea of funnel-based control, we show that a fragment of STL specifications can be formulated as assume-guarantee contracts. A new concept of contract satisfaction is then defined to establish our compositionality result, which allows us to guarantee the satisfaction of a global contract by the interconnected system when all subsystems satisfy their local contracts. Based on this compositional framework, we then design closed-form continuous-time feedback controllers to enforce local contracts over subsystems in a decentralized manner. Finally, we demonstrate the effectiveness of our results on two numerical examples. Copyright © 2022, The Authors. All rights reserved.

关键词： Continuous time systems

Finite-time Identification of Stable Linear systems Optimality of the Least-Squares Estimator

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Finite-time Identification of Stable Linear Systems Optimali...

IEEE Conference on decision and control

作者： Yassir Jedra Alexandre Proutiere Division of Decision and Control Systems School of Electrical Engineering and Computer Science Royal institute of Technology (KTH) Stockholm Sweden

ISBN: (数字)9781728174471

ISBN: (纸本)9781728174488

We present a new finite-time analysis of the estimation error of the Ordinary Least Squares (OLS) estimator for stable linear time-invariant systems. We characterize the number of observed samples (the length of the observed trajectory) sufficient for the OLS estimator to be (ε, δ)-PAC, i.e., to yield an estimation error less than ε with probability at least 1 - δ. We show that this number matches existing sample complexity lower bounds [1], [2] up to universal multiplicative factors (independent of (ε, δ) and of the system). This paper hence establishes the optimality of the OLS estimator for stable systems, a result conjectured in [1]. Our analysis of the performance of the OLS estimator is simpler, sharper, and easier to interpret than existing analyses. It relies on new concentration results for the covariates matrix.

关键词： Complexity theory Upper bound Trajectory Linear systems Estimation error Covariance matrices Matrix decomposition

Finite sample guarantees for quantile estimation: An application to detector threshold tuning

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arXiv 2021年

作者： Umsonst, David Ruths, Justin Sandberg, Henrik The Division of Decision and Control Systems The School of Electrical Engineering and Computer Science The KTH Royal Institute of Technology Stockholm10044 Sweden The Department of Mechanical Engineering The University of Texas at Dallas 800 W. Campbell Rd RichardsonTX United States

In threshold-based anomaly detection, we want to tune the threshold of a detector to achieve an acceptable false alarm rate. However, tuning the threshold is often a non-trivial task due to unknown detector output distributions. A detector threshold that provides an acceptable false alarm rate is equivalent to a specific quantile of the detector output distribution. Therefore, we use quantile estimators based on order statistics to estimate the detector threshold. The estimation of quantiles from sample data has a more than a century long tradition and we provide three different distribution-free finite sample guarantees for a class of quantile estimators. The first is based on the Dworetzky-Kiefer-Wolfowitz inequality, the second utilizes the Vysochanskij-Petunin inequality, and the third is based on exact confidence intervals for a beta distribution. These guarantees are then compared and used in the detector threshold tuning problem. We use both simulated data as well as data obtained from an experimental setup with the Temperature control Lab to validate the guarantees provided. Copyright © 2021, The Authors. All rights reserved.

关键词： Sampling