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Exogenous input and state estimation for a class of nonlinear dynamic systems in the presence of the unknown but bounded disturbances

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International Journal of Dynamics and control 2019年第1期7卷 226-240页

作者： Alirezapouri, M.A. Vali, A.R. Khaloozadeh, H. Arvan, M.R. Faculty of Electrical and Computer Engineering Malek-Ashtar University of Technology Tehran Iran Departments of System and Control Faculty of Electrical Engineering K. N. Toosi University of Technology Tehran Iran

Estimation of the exogenous input is an important topic in various applications. Unknown inputs can dramatically degrade the estimation performance in systems with unknown but bounded (UBB) disturbances. In this study, based on UBB assumption of the input and observation disturbances, a method is proposed for simultaneous estimation of the unknown input, state vector, and disturbance for a class of nonlinear dynamical systems. Based on the affine transformation of convex sets, disturbance and unknown input are considered as new state variables and therefore the nonlinear system of state equations is rearranged. Based on interval mathematics, the linearization error of the process and observation equations are bounded with convex closed sets and then combined with the ellipsoidal sets that representing system disturbance. The augmented state vector is estimated based on extended set value observer. To satisfy the stability of the proposed method, the input to state stability and boundedness of the estimation error is analyzed. The proposed method performance is verified by various numerical simulations and compared with other input estimation methods. Numerical simulations show the acceptable performance of the proposed algorithm in the simultaneously estimation of the unknown input, disturbance, and state vector rather than other unknown input estimation method. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.

关键词： Nonlinear dynamical systems

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Non-linear feature extraction from HRV signal for mortality prediction of ICU cardiovascular patient

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Journal of Medical engineering and Technology 2016年第3期40卷 87-98页

作者： Moridani, Mohammad Karimi Setarehdan, Seyed Kamaledin Motie Nasrabadi, Ali Hajinasrollah, Esmaeil Department of Biomedical Engineering Science and Research Branch Islamic Azad University Tehran Iran Control and Intelligent Processing Centre of Excellence School of Electrical and Computer Engineering College of Engineering University of Tehran Tehran Iran Departments of Biomedical Engineering Shahed University Tehran Iran Loghman Medical Center Shahid Beheshti University of Medical Sciences Tehran Iran

Intensive care unit (ICU) patients are at risk of in-ICU morbidities and mortality, making specific systems for identifying at-risk patients a necessity for improving clinical care. This study presents a new method for predicting in-hospital mortality using heart rate variability (HRV) collected from the times of a patients ICU stay. In this paper, a HRV time series processing based method is proposed for mortality prediction of ICU cardiovascular patients. HRV signals were obtained measuring R-R time intervals. A novel method, named return map, is then developed that reveals useful information from the HRV time series. This study also proposed several features that can be extracted from the return map, including the angle between two vectors, the area of triangles formed by successive points, shortest distance to 45° line and their various combinations. Finally, a thresholding technique is proposed to extract the risk period and to predict mortality. The data used to evaluate the proposed algorithm obtained from 80 cardiovascular ICU patients, from the first 48 h of the first ICU stay of 40 males and 40 females. This study showed that the angle feature has on average a sensitivity of 87.5% (with 12 false alarms), the area feature has on average a sensitivity of 89.58% (with 10 false alarms), the shortest distance feature has on average a sensitivity of 85.42% (with 14 false alarms) and, finally, the combined feature has on average a sensitivity of 92.71% (with seven false alarms). The results showed that the last half an hour before the patients death is very informative for diagnosing the patients condition and to save his/her life. These results confirm that it is possible to predict mortality based on the features introduced in this paper, relying on the variations of the HRV dynamic characteristics. © 2016 Taylor & Francis.

关键词： Forecasting

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PID2018 Benchmark Challenge: Multi-Objective Stochastic Optimization Algorithm

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IFAC-PapersOnLine 2018年第4期51卷 877-881页

作者： Ates, Abdullah Yuan, Jie Dehghan, Sina Zhao, Yang Yeroglu, Celaleddin Chen, YangQuan Inonu University Computer Engineering Department Malatya44280 Turkey School of Automation Southeast University Nanjing210096 China UC Merced Mechanical Engineering Departments MESA Lab MercedCA95301 United States School of Control Science and Engineering at Shandong University Jinan250061 China

This paper presents a multi-objective stochastic optimization method for tuning of the controller parameters of Refrigeration Systems based on Vapour Compression. Stochastic Multi Parameter Divergence Optimization (SMDO) algorithm is modified for minimization of the Multi Objective function for optimization process. System control performance is improved by tuning of the PI controller parameters according to discrete time model of the refrigeration system with multi objective function by adding conditional integral structure that is preferred to reduce the steady state error of the system. Simulations are compared with existing results via many graphical and numerical solutions. © 2018

关键词： Multiobjective optimization

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Internet Congestion control

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IEEE control Systems 2002年第1期22卷 28-43页

作者： Low, Steven H. Paganini, Fernando Doyle, John C. Departments of Computer Science and Electrical Engineering California Institute of Technology Pasadena CA 91125 United States Department of Electrical Engineering University of California Los Angeles CA 90095 United States Departments of Electrical Engineering and Control and Dynamical Systems California Institute of Technology Pasadena CA 91125 United States

This article reviews the current transmission control protocol (TCP) congestion control protocols and overviews recent advances that have brought analytical tools to this problem. We describe an optimization-based framework that provides an interpretation of various flow control mechanisms, in particular, the utility being optimized by the protocol's equilibrium structure. We also look at the dynamics of TCP and employ linear models to exhibit stability limitations in the predominant TCP versions, despite certain built-in compensations for delay. Finally, we present a new protocol that overcomes these limitations and provides stability in a way that is scalable to arbitrary networks, link capacities, and delays.

关键词： Internet Stability control systems Delay Access protocols Size control IP networks Feedback Analytical models Aggregates

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Convexification of optimal power flow problem

Convexification of optimal power flow problem

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48th Annual Allerton Conference on Communication, control, and Computing, Allerton 2010

作者： Lavaei, Javad Low, Steven H. Department of Control and Dynamical Systems California Institute of Technology United States Computer Science and Electrical Engineering Departments California Institute of Technology United States

ISBN: (纸本)9781424482146

The optimal power flow (OPF) problem is nonconvex and generally hard to solve. We provide a sufficient condition under which the OPF problem is equivalent to a convex problem and therefore is efficiently solvable. Specifically, we prove that the dual of OPF is a semidefinite program and our sufficient condition guarantees that the duality gap is zero and a globally optimal solution of OPF is recoverable from a dual optimal solution. This sufficient condition is satisfied by standard IEEE benchmark systems with 14, 30, 57, 118 and 300 buses after small resistance (10-5 per unit) is added to every transformer that originally assumes zero resistance. We justify why the condition might hold widely in practice from algebraic and geometric perspectives. The main underlying reason is that physical quantities such as resistance, capacitance and inductance, are all positive. ©2010 IEEE.

关键词： Electric load flow

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Utility functionals associated with available congestion control algorithms

Utility functionals associated with available congestion con...

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IEEE INFOCOM 2010

作者： Lavaei, Javad Doyle, John C. Low, Steven H. Department of Control and Dynamical Systems California Institute of Technology United States Computer Science and Electrical Engineering Departments California Institute of Technology United States

ISBN: (纸本)9781424458363

This paper is concerned with understanding the connection between the existing Internet congestion control algorithms and the optimal control theory. The available resource allocation controllers are mainly devised to derive the state of the system to a desired equilibrium point and, therefore, they are oblivious to the transient behavior of the closed-loop system. To take into account the real-time performance of the system, rather than merely its steady-state performance, the congestion control problem should be solved by maximizing a proper utility functional as opposed to a utility function. For this reason, this work aims to investigate what utility functionals the existing congestion control algorithms maximize. In particular, it is shown that there exist meaningful utility functionals whose maximization leads to the celebrated primal, dual and primal/dual algorithms. An implication of this result is that a real network problem may be solved by regarding it as an optimal control problem on which some practical constraints, such as a real-time link capacity constraint, are imposed. ©2010 IEEE.

关键词： Closed loop systems

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A Markov process using curvature for filtering curve images 3rd

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3rd International Workshop on Energy Minimization Methods in computer Vision and Pattern Recognition, EMMCVPR 2001

作者： August, Jonas Zucker, Steven W. Center for Computational Vision and Control Departments of Electrical Engineering and Computer Science Yale University 51 Prospect Street New HavenCT06520 United States

ISBN: (纸本)3540425233

A Markov process model for contour curvature is introduced via a stochastic differential equation. We analyze the distribution of such curves, and show that its mode is the Euler spiral, a curve minimizing changes in curvature. To probabilistically enhance noisy and low contrast curve images (e.g., edge and line operator responses), we combine this curvature process with the curve indicator random field, which is a prior for ideal curve images. In particular, we provide an expression for a nonlinear, minimum mean square error filter that requires the solution of two elliptic partial differential equations. Initial computations are reported, highlighting how the filter is curvature-selective, even when curvature is absent in the input. © Springer-Verlag Berlin Heidelberg 2001.

关键词： Markov processes

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PMU based transient stabilization using FACTS

PMU based transient stabilization using FACTS

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2011 IEEE/PES Power Systems Conference and Exposition, PSCE 2011

作者： Cvetković, Miloš Ilić, Marija Department of Electrical and Computer Engineering Carnegie Mellon University Pittsburgh PA 15213 United States Carnegie Mellon University Electrical and Computer Engineering and Engineering and Public Policy Departments Pittsburgh PA United States Control of Future Electricity Network Operations at Delft University of Technology Delft Netherlands

ISBN: (纸本)9781612847870

Phasor Measurement Units (PMU) and Flexible AC Transmission Systems (FACTS) have great potential for stabilizing response of the power grid to the large disturbances. A combination of both technologies can result in very powerful near-real time sensing and control capable of monitoring and counteracting the effects of very fast disturbances. In this paper we propose fast switching of FACTS devices which is guaranteed to transiently stabilize the system using very fast and accurate PMU measurements. The nonlinear control law proposed in this paper is based and designed upon understanding the physical system-wide effects of a fault. The control law can be interpreted in terms of controling stored energy flow dynamics and it is also derived using energy-based high gain control methods for nonlinear systems. As such, it is entirely scalable and applicable to any size system. The location of PMUs and the design of systemwide communications for given locations of FACTS devices is directly determined using the designed control law. FACTS control of this type would not be possible without having the accuracy and sampling rate of PMUs. © 2011 IEEE.

关键词： Phasor measurement units

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Local WMR navigation with monocular data

Local WMR navigation with monocular data

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International Conference on Autonomous Robots and Agents, ICARA

作者： Lluis Pacheco Ningsu Luo Xavier Cufi Javier Cobos Departments of Computer Engineering and Electronics and Control Engineering University of Girona Girona Spain

This article presents recent WMR (wheeled mobile robot) navigation experiences using local perception knowledge provided by monocular and odometer systems. A local narrow perception horizon is used to plan safety trajectories towards the objective. Therefore, monocular data are proposed as a way to obtain real time local information by building two dimensional occupancy grids through a time integration of the frames. The path planning is accomplished by using attraction potential fields, while the trajectory tracking is performed by using model predictive control techniques. The results are faced to indoor situations by using the lab available platform consisting in a differential driven mobile robot.

关键词： Navigation Robot kinematics Mobile robots Trajectory Robot sensing systems Path planning Predictive models Predictive control Robot localization Animals

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Costs and benefits of transmission congestion management

Costs and benefits of transmission congestion management

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2011 IEEE/PES Power Systems Conference and Exposition, PSCE 2011

作者： Ilić, Marija D. Bachovchin, Kevin D. Lewis, Amelia S. Department of Electrical and Computer Engineering Carnegie Mellon University Pittsburgh PA 15213 United States Carnegie Mellon University Pittsburgh PA United States Electrical and Computer Engineering and Engineering and Public Policy Departments United States Control of Future Electricity Network Operations Delft University of Technology Delft Netherlands

ISBN: (纸本)9781612847870

Transmission congestion is a major economic and reliability concern in today's electric power systems. However, as the industry undergoes changes, it becomes critically important to better understand the fundamental role of transmission and its technical and financial effects on the electricity provision. Thermal limits, voltage drop regulation, and voltage stability limits are among the most common causes of transmission congestion. In order to relieve congestion, new transmission can be built or reactive power control can be installed. In this paper, simple power systems are analyzed in order to compare costs of different ways of reducing congestion. The length of a transmission line determines the cause and the most cost effective solution. For short lines, the thermal limit is the limiting factor in determining the maximum power flow and building new transmission is the only effective solution. For longer lines, the voltage drop regulation is the limiting factor and adding a shunt capacitor is the most cost effective solution. © 2011 IEEE.

关键词： Cost effectiveness

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