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Optimal weight allocation of dynamic distribution networks and positive semi-definiteness of signed laplacians

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arXiv 2018年

作者： Wei, Jieqiang Johansson, Alexander Sandberg, Henrik Johansson, Karl H. Chen, Jie Department of Automatic control School of Electrical Engineering and Computer Science KTH Royal Institute of Technology StockholmSE-100 44 Sweden Department of Electronic Engineering City University of Hong Kong Hong Kong Hong Kong

In this paper, we consider the robustness of a basic model of a dynamical distribution network. In the first problem, i.e., optimal weight allocation, we minimize the H∞- norm of the dynamical distribution network subject to allocation of the weights on the edges. It is shown that this optimization problem can be formulated as a semi-definite program. Next we consider the semi-definiteness of the weighted graph Laplacian matrix with negative weights on the edges. A necessary and sufficient condition, using the effective resistance matrix, is established to guarantee the positive semi-definiteness of the Laplacian matrix. Furthermore, the bounded real lemma is derived for state-space symmetric systems. Copyright © 2018, The Authors. All rights reserved.

关键词： Laplace transforms

Alternating iterative secure structure between beamforming and power allocation for UAV-aided directional modulation networks

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arXiv 2018年

作者： Shu, Feng Lu, Zaoyu Lin, Jinyong Sun, Linlin Zhou, Xiaobo Liu, Tingting Zhang, Shuo Cai, Wenlong Lu, Jinhui Wang, Jin School of Electronic and Optical Engineering Nanjing University of Science and Technology 210094 China School of Computer and information Fujian Agriculture and Forestry University Fuzhou350002 China Beijing Aerospace Automatic Control Institute Beijing100854 China

In unmanned aerial vehicle (UAV) networks, directional modulation (DM) is adopted to improve the secrecy rate (SR) performance. Alice, a ground base station, behaves as a control center, and Bob is a UAV of flying along a linear flight trajectory who optimizes its SR performance by dynamically adjusting its beamforming vectors and power allocation (PA) strategy. Per fixed time interval during the Bob’s flight process, the transmit beamforming vectors for useful messages and AN projection are given by the rule of maximizing signal-to-leakage- and-noise ratio (Max-SLNR) and maximizing AN-and-leakage-to-noise ratio (ANLNR), and the optimal PA strategy is based on maximizing SR (Max-SR). More importantly, an alternating iterative structure (AIS) between beamforming and PA is proposed to further improve the SR performance. Simulation results show that the proposed AIS converges rapidly, and can achieve substantial SR gains over Max-SLNR plus Max-ANLNR with fixed PA such as PA factor β = 0.5, and 0.9. In particular, in the case of small-scale antenna array, the SR performance gain achieved by the proposed AIS is more attractive. Additionally, as the number of antennas tends to be large-scale, the average SR performance of the proposed AIS approaches an SR ceil. Copyright © 2018, The Authors. All rights reserved.

关键词： Beamforming

Mask-aware networks for crowd counting

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arXiv 2018年

作者： Jiang, Shengqin Lu, Xiaobo Lei, Yinjie Liu, Lingqiao School of Computer Science University of Adelaide AdelaideSA5005 Australia Key Laboratory of Measurement and Control of Complex Systems of Engineering Ministry of Education Nanjing210096 China School of Automatic Southeast University Nanjing210096 China Control of Complex Systems of Engineering Ministry of Education Nanjing210096 China College of Electronics and Information Engineering Sichuan University Chengdu610064 China School of Computer Science University of Adelaide AdelaideSA5005 Australia

Crowd counting problem aims to count the number of objects within an image or a frame in the videos and is usually solved by estimating the density map generated from the object location annotations. The values in the density map, by nature, take two possible states: zero indicating no object around, a non-zero value indicating the existence of objects and the value denoting the local object density. In contrast to traditional methods which do not differentiate the density prediction of these two states, we propose to use a dedicated network branch to predict the object/non-object mask and then combine its prediction with the input image to produce the density map. Our rationale is that the mask prediction could be better modeled as a binary segmentation problem and the difficulty of estimating the density could be reduced if the mask is known. A key to the proposed scheme is the strategy of incorporating the mask prediction into the density map estimator. To this end, we study five possible solutions, and via analysis and experimental validation we identify the most effective one. Through extensive experiments on five public datasets, we demonstrate the superior performance of the proposed approach over the baselines and show that our network could achieve the state-of-the-art performance. Copyright © 2018, The Authors. All rights reserved.

关键词： Forecasting

A poincaré-bendixson theorem for hybrid systems

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arXiv 2018年

作者： Clark, William Bloch, Anthony Colombo, Leonardo Department of Mathematics University of Michigan 530 Church Street Ann ArborMI United States Department of Automatic Control School of Electrical Engineering and Computer Sciences KTH Royal Institute of Technology StockholmSE-100 44 Sweden

The Poincaré-Bendixson theorem plays an important role in the study of the qualitative behavior of dynamical systems on the plane;it describes the structure of limit sets in such systems. We prove a version of the Poincaré-Bendixson Theorem for two dimensional hybrid dynamical systems and describe a method for computing the derivative of the Poincaré return map, a useful object for the stability analysis of hybrid systems. We also prove a Poincaré-Bendixson Theorem for a class of one dimensional hybrid dynamical systems.34A38, 34C25, 34D20, 70K05, 70K20, 70K42 Copyright © 2018, The Authors. All rights reserved.

关键词： Hybrid systems

Two practical random-subcarrier-selection methods for secure precise wireless transmission

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arXiv 2018年

作者： Shen, Tong Zhang, Shuo Chen, Riqing Wang, Jin Hu, Jinsong Shu, Feng Wang, Jiangzhou School of Electronic and Optical Engineering Nanjing University of Science and Technology 210094 China School of Computer and information Fujian Agriculture and Forestry University Fuzhou350002 China National Key Laboratory of Science and Technology on Aerospace Intelligence Control Beijing Aerospace Automatic Control Institute Beijing100854 China School of Engineering and Digital Arts University of Kent CanterburyCT2 7NT United Kingdom

In directional modulation (DM) networks, two practical random-subcarrier-selection (RSS) methods are proposed to transmit confidential message to the desired user per orthogonal frequency division multiplexing (OFDM) symbol with only single receive power peak formed by constructing random subcarrier set and performing a randomization procedure. This scheme completely addresses the crucial problem facing secure precise wireless transmission (SPWT), how to achieve the SPWT per OFDM symbol while the traditional SPWT holds only in the statistically average sense. Several necessary conditions for SPWT per OFDM is derived and proposed: random, distributed, and distinct subcarrier spacing pattern mapped onto transmit antenna array. Two random subcarrier index sets, quadratic subcarrier set (QSS) and prime subcarrier set (PSS), are constructed. Subsequently, a random metric is defined, and a randomization procedure (RP) is proposed. Its detailed process includes the following steps: integer mod, ordering, blocking, and block interleaving (BI) where BI is repeated until the random metric is greater than the predefined value. This yields a single high energy main peak (SHEMP) at the desired position with other positions, outside the main peak, harvesting only weak receive energy seriously corrupted by AN. Simulation results confirm that our proposed two methods, QSS plus RP and PSS plus RP, perform significantly better than conventional methods such as linear subcarrier set (LSS) plus RP. They actually form a SHEMP at desired position, and generate only extremely small leakage outside the main peak. Copyright © 2018, The Authors. All rights reserved.

关键词： Orthogonal frequency division multiplexing

A decision-making framework for robust multi-agent systems in risky communication scenarios

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A decision-making framework for robust multi-agent systems i...

AIAA Information Systems-AIAA Infotech at Aerospace, 2018

作者： Samiei, Arezoo Hu, Bin Zhao, Shiyu Sun, Liang Klipsch School of Electrical and Computer Engineering New Mexico State University Thomas & Brown Hall 1125 Frenger Mall Las CrucesNM88003 United States Department of Engineering Technology Old Dominion University Kaufman Hall 211C NorfolkVA23529 United States Department of Automatic Control and Systems Engineering University of Sheffield Mappin Street SheffieldS1 3JD United Kingdom Department of Mechanical and Aerospace Engineering New Mexico State University Jett Hall Rm. 104 1040 S. Horseshoe Street Las CrucesNM88003 United States

ISBN: (数字)9781624105272

ISBN: (纸本)9781624105272

In this paper, we present a novel decision-making framework to characterize the communication status of a distributed multi-agent system. The theoretical package dropout probability (PDP) in communication is formulated as a function of the inter-distance between agents. A statistical representation is adopted to describe the actual value of the PDP. The communication status, formulated as a binary variable, is then determined by the comparison between the theoretical PDP and its statistical representation. To handle the unexpected degradation/loss of the communication network, an algorithm is proposed to quickly examine the robustness of the communication network in the case of single-node failure, i.e., the biconnectivity of a graph. The proposed framework is tested in scenarios of changing formation and temporary- and permanent-loss of communication. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

关键词： Multi agent systems

Robust Self-tuning control Based on Discrete-time Sliding Mode for Auto-regressive Mathematical Model in the Presence of Unmodelled Dynamics

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International Journal of Automation and computing 2016年第3期13卷 277-284页

作者： Nabiha Touijer Samira Kamoun Laboratory of Sciences and Techniques of Automatic Control and Computer Engineering (Lab-STA) National School of Engineering of SfaxUniversity of Sfax

In this paper, we propose a new robust selfbtuning control, called the generalized minimum variance a/-equivalent self- tuning control （GMVSTC-a/） for the linear timevarying （LTV） systems, which can be described by the discrete-time auto-regressive exogenous （ARX） mathematical model in the presence of unmodelled dynamics. The estimation of the parameters contained in this mathematical model is made on the basis of the proposed modified recursive least squares （m-RLS） parametric estimation algorithm with dead zone and forgetting factor. The stability analysis of the proposed parametric estimation algorithm m-RLS is treated on the basis of a Lyapunov function. A numerical simulation example is used to prove the performances and the effectiveness of the explicit scheme of the proposed robust self-tuning control GMVSTC-a/.

关键词： Discrete-time systems parametric uncertainty robust estimation robust self-tuning control sliding mode control sta-bility.

Distributed Optimization for Second-Order Multi-Agent Systems with Dynamic Event-Triggered Communication

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arXiv 2018年

作者： Yi, Xinlei Yao, Lisha Yang, Tao George, Jemin Johansson, Karl H. Department of Automatic Control Kth Royal Institute of Technology School of Electrical Engineering and Computer Science Stockholm100 44 Sweden Department of Electrical Engineering University of North Texas DentonTX76203 United States U.S. Army Research Laboratory AdelphiMD20783 United States

In this paper, we propose a fully distributed algorithm for second-order continuous-time multi-agent systems to solve the distributed optimization problem. The global objective function is a sum of private cost functions associated with the individual agents and the interaction between agents is described by a weighted undirected graph. We show the exponential convergence of the proposed algorithm if the underlying graph is connected, each private cost function is locally gradient-Lipschitz-continuous, and the global objective function is restricted strongly convex with respect to the global minimizer. Moreover, to reduce the overall need of communication, we then propose a dynamic event-triggered communication mechanism that is free of Zeno behavior. It is shown that the exponential convergence is achieved if the private cost functions are also globally gradient-Lipschitz-continuous. Numerical simulations are provided to illustrate the effectiveness of the theoretical results. Copyright © 2018, The Authors. All rights reserved.

关键词： Multi agent systems

Machine-Learning-based High-resolution DOA Measurement and Robust DM for Hybrid Analog-Digital Massive MIMO Transceiver

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arXiv 2018年

作者： Shu, Feng Xu, Ling Lin, Jinyong Hu, Jingsong Gui, Linqing Li, Jun Wang, Jiangzhou School of Electronic and Optical Engineering Nanjing University of Science and Technology 210094 China College of Computer and Information Sciences Fujian Agriculture and Forestry University Fuzhou350002 China Beijing Aerospace Automatic Control Institute Beijing100854 China School of Engineering and Digital Arts University of Kent CanterburyCT2 7NT United Kingdom

—At hybrid analog-digital (HAD) transceiver, an improved HAD rotational invariance techniques (ESPRIT), called I-HAD-ESPRIT, is proposed to measure the direction of arrival (DOA) of desired user, where the phase ambiguity due to HAD structure is addressed successfully. Subsequently, a machine-learning (ML) framework is proposed to improve the precision of measuring DOA. In the training stage, the HAD transceiver works as a receiver and repeatedly measures the values of DOA via I-HAD-ESPRIT to form a slightly large training data set (TDS) of DOA. From TDS, we find that the probability density function (PDF) of DOA measurement error (DOAME) is approximated as a Gaussian distribution by the histogram method in ML. This TDS is used to learn the mean of DOA and the variance of DOAME, which are utilized to infer their values and improve their precisions in the real-time stage. The HAD transceiver rapidly measures the real-time value of DOA some times to form a relatively small real-time set (RTS), which is used to learn the real-time mean and variance of DOA/ DOAME. Then, three weight combiners are proposed to combine the-maximum-likelihood-learning outputs of TDS and RTS. Their weight factors depend intimately on the numbers of elements in TDS and RTS, and signal-to-noise ratios during the two stages. Using the mean and variance of DOA/DOAME, their PDFs can be given directly, and we propose a robust beamformer for directional modulation (DM) transmitter with HAD by fully exploiting the PDF of DOA/DOAME, especially a robust analog beamformer on RF chain. Simulation results show that: 1) The proposed I-HAD-ESPRIT can achieve the HAD CRLB;2) The proposed ML framework performs much better than the corresponding real-time one without training stage, 3) The proposed robust DM transmitter can perform better than the corresponding nonrobust ones in terms of bit error rate and secrecy rate. Copyright © 2018, The Authors. All rights reserved.

关键词： Direction of arrival