A survey on delayed feedback control of chaos

This paper introduces the basic idea and provides the mathematical formulation of the delayed feedback control （DFC） methodology, which has been widely used in chaos control. Stability analysis including the well-known odd number linfitation of the DFC is reviewed. Some new developments in characterizing the limitation of the DFC are presented. Various modified DFC methods, which are developed in order to overcome the odd number limitation, are also described. Finally, some open problems in this research field are discussed.     

Neural network solution for finite-horizon H ∞ state feedback control of nonlinear systems

In this article, neural networks are used to approximately solve the finite-horizon optimal H _∞ state feedback control problem. The method is based on solving a related Hamilton–Jacobi–Isaacs equation of the corresponding finite-horizon zero-sum game. The neural network approximates the corresponding game value function on a certain domain of the state-space and results in a control computed as the output of a neural network. It is shown that the neural network approximation converges uniformly to the game-value function and the resulting controller provides closed-loop stability and bounded L ₂ gain. The result is a nearly exact H _∞ feedback controller with time-varying coefficients that is solved a priori offline. The results of this article are applied to the rotational/translational actuator benchmark nonlinear control problem.     

Implementation of digital controllers—A survey

Stimulated by microprocessor technology there is increasing interest in the issues of digital control implementation. This paper reviews these issues, from algorithms through current hardware up to the various problems arising with non-ideal behaviour of digital controllers.     

A stabilizing control for a class of uncertain linear delayed systems via state feedback—Development of the results

Stabilization of uncertain delayed systems via linear state feedback including no delays is considered. The present report is a development of the previous results. It is shown that the obtained condition is fundamentally equivalent to Wei's results called antisymmetric stepwise configuration. He constructed his results for the stabilization of a linear system including no delays.     

The current state of control loop performance monitoring – A survey of application in industry

Control loop performance monitoring (CPM) in industrial production processes is an established area of research for which many methods to detect malfunctioning loops have been developed. However, it is unclear which methods are successful in an industrial environment. Often, there are additional aspects such as organizational issues, data availability and access that can compromise the use of CPM. In this paper, we are reporting on the results of a survey amongst CPM users. The survey takes stock of existing methods and their use in industry as well as which faults are most frequent and can be detected. Organizational as well as implementation issues are investigated and discussed. This paper aims to identify open research topics and the direction of development of CPM in industrial production processes.     

Decomposition of binary images—A survey and comparison

We present an overview of the most important methods that decompose an arbitrary binary object into a union of rectangles. We describe a run-length encoding and its generalization, decompositions based on quadtrees, on mathematical morphology, on the distance transform, and a theoretically optimal decomposition based on a maximal matching in bipartite graphs. We compare their performance in image compression, in moment computation and in linear filtering. We show that the choice is always a compromise between the complexity and time/memory consumption. We give advice how to select an appropriate method in particular cases.     

A survey of applications of threshold cryptography—proposed and practiced

ABSTRACT

Threshold cryptography is a secret sharing technique that finds applications in many fields including cloud computing, authentication, the Internet of Things, ad-hoc and sensor networks, digital signatures, and electronic voting. The technique can effectively reduce the total number of cryptographic keys used for encryption in a group. The article surveys the multifaceted applications of threshold cryptography, portraying the techniques and the secret sharing schemes used. The article also emphasizes the immediate need for reviving the expired Internet Engineering Task Force (IETF) draft of 2010 to establish a threshold cryptography standard.     

Microcomputer control of high dynamic performance ac-drives—A survey

Alternating current machines, in particular induction motors, are of simple mechanical construction but have a nonlinear, highly interacting multivariable control structure. This has made it difficult in the past to design controlled ac-drives with high dynamic performance, similar to converter-fed dcdrives. A satisfactory solution of this problem has not been available until Blaschke formulated the principle of field orientation, where the machine is controlled in a moving frame of reference. This paper presents a survey of controlling acmachines for use in high dynamic performance drives including different types of machines and converters with their specific control characteristics. It is shown that by combining a suitable machine model with the principle of rotor- or field-orientation a unifying basis for the design of ac-drives is created. The complicated signal structure of the control systems can very effectively be handled by microelectronics, i.e. by using software instead of elaborate hardware. This is shown in the paper with the help of examples.     

Two decades of Web application testing—A survey of recent advances

Since its inception of just over two decades ago, the World Wide Web has become a truly ubiquitous and transformative force in our life, with millions of Web applications serving billions of Web pages daily. Through a number of evolutions, Web applications have become interactive, dynamic and asynchronous. The Web׳s ubiquity and our reliance on it have made it imperative to ensure the quality, security and correctness of Web applications. Testing is a widely used technique for validating Web applications. It is also a long-standing, active and diverse research area. In this paper, we present a broad survey of recent Web testing advances and discuss their goals, targets, techniques employed, inputs/outputs and stopping criteria.     

A structure-preserving algorithm for the minimum H ∞ norm computation of finite-time state feedback control problem

The algorithm being developed here is based on the generating function approach for finite-time H _∞ control and application of canonical transformation of linear Hamiltonian system. First, an equivalent finite-time H _∞ control law in terms of the third-type generating function is derived. Then, by using symplectic structure of the Hamiltonian system's state transition matrix, a group of matrix recursive formulae are deduced for the evaluation of the finite-time H _∞ control law. Combining with a matrix singularity testing procedure, this recursive algorithm verifies the existence condition of sub-optimal H _∞ controllers and gives the minimum H _∞ norm of finite-time control systems. Inherited from the canonical transformation, the matrix recursive formulae have a standard symplectic form; this structure-preserving property helps facilitate reliable and effective computation. Numerical results show the effectiveness of the proposed algorithm.     

Dual arm manipulation—A survey

Recent advances in both anthropomorphic robots and bimanual industrial manipulators had led to an increased interest in the specific problems pertaining to dual arm manipulation. For the future, we foresee robots performing human-like tasks in both domestic and industrial settings. It is therefore natural to study specifics of dual arm manipulation in humans and methods for using the resulting knowledge in robot control. The related scientific problems range from low-level control to high level task planning and execution. This review aims to summarize the current state of the art from the heterogenous range of fields that study the different aspects of these problems specifically in dual arm manipulation.     

Intelligent visual surveillance — A survey

Detection, tracking, and understanding of moving objects of interest in dynamic scenes have been active research areas in computer vision over the past decades. Intelligent visual surveillance (IVS) refers to an automated visual monitoring process that involves analysis and interpretation of object behaviors, as well as object detection and tracking, to understand the visual events of the scene. Main tasks of IVS include scene interpretation and wide area surveillance control. Scene interpretation aims at detecting and tracking moving objects in an image sequence and understanding their behaviors. In wide area surveillance control task, multiple cameras or agents are controlled in a cooperative manner to monitor tagged objects in motion. This paper reviews recent advances and future research directions of these tasks. This article consists of two parts: The first part surveys image enhancement, moving object detection and tracking, and motion behavior understanding. The second part reviews wide-area surveillance techniques based on the fusion of multiple visual sensors, camera calibration and cooperative camera systems.     

Structural shape optimization—A survey

This paper is a survey of structural shape optimization with an emphasis on techniques dealing with shape optimization of the boundaries of two- and three-dimensional bodies. Attention is focused on the special problems of structural shape optimization which are due to a finite element model which must change during the optimization process. These problems include the requirement for sophisticated automated mesh generation techniques and careful choice of design variables. They also include special problems in obtaining sufficiently accurate sensitivity derivatives.     

Stability impact of small delays in proportional–derivative state feedback

This paper points out specific stability problems of the state derivative and proportional–derivative state feedback which may result from the presence of otherwise negligible delays in the control loops. It is shown that the stability problems arise from the neutral character of the closed-loop system with the state derivative action under small delay perturbations. As the main result, a stability criterion is derived for a safe implementation of the state derivative feedback. Furthermore, a scheme including filtered state derivative feedback is proposed to overcome the destabilizing effects of small feedback delays. Two application examples are presented. From a theoretical point of view, the main contribution of the paper lies in the stability theory of linear neutral equations with dependent delays, subjected to delay perturbations.     

Application of facial reduction to H ∞ state feedback control problem

One often encounters numerical difficulties in solving linear matrix inequality (LMI) problems obtained from H _∞ control problems. For semidefinite programming (SDP) relaxations for combinatorial problems, it is known that when either an SDP relaxation problem or its dual is not strongly feasible, one may encounter such numerical difficulties. We discuss necessary and sufficient conditions to be not strongly feasible for an LMI problem obtained from H _∞ state feedback control problems and its dual. Moreover, we interpret the conditions in terms of control theory. In this analysis, facial reduction, which was proposed by Borwein and Wolkowicz, plays an important role. We show that the dual of the LMI problem is not strongly feasible if and only if there exist invariant zeros in the closed left-half plane in the system, and present a remedy to remove the numerical difficulty with the null vectors associated with invariant zeros in the closed left-half plane. Numerical results show that the numerical stability is improved by applying it.     

Global stabilizer of a general class of feedback nonlinear systems and its exponential convergence

1IntroductionThe problem of stabilizing feedback system has beenstudied extensively,such as[1~3],etc.For a generalfeedback nonlinear systems,there’s no workablestabilization theory when priori information on systemnonlinearities is known.However,inthis paper,we proposean universal global stabilizer for a general class of feedbacksystems,which does not require any priori knowledge ofsystemnonlinearities.We consider a general class of feedback nonlinearsystems:dx1dt=f1(u),dx2dt=f2(x1,u),┇dxn-1…     

H∞ output feedback control for large-scale nonlinear systems with time delay in both state and input

The H∞ output feedback control problem for a class of large-scale nonlinear systems with time delay in both state and input is considered in this paper. It is assumed that the interconnected nonlinearities are limited by constant multiplied by unmeasured states, delayed states and external disturbances. Different from existing methods to study the H∞ control of large-scale nonlinear systems, the static gain control technique is utilized to obtain an observer-based output feedback control strategy, which makes the closed-loop system globally asymptotically stable and attenuates the effect of external disturbances. An example is finally carried out to show the feasibility of the proposed control strategy.