Showing papers in "International Journal of Systems Science in 2012"
TL;DR: A novel consensus protocol is designed to solve the group consensus problem in networks of dynamic agents where the agents in a sub-network share a consistent value while there is no agreement between any two sub-nets.
Abstract: We discuss a new consensus problem – a group consensus problem – in networks of dynamic agents. For a complex network consisting of several sub-networks owing to physical quantities or task distributions, it is concerned with this case that the agents in a sub-network share a consistent value while there is no agreement between any two sub-networks. When the information exchange is directed, a novel consensus protocol is designed to solve the group consensus problem. The convergence analysis is discussed and several criteria are established based on graph theories and matrix theories. Simulation results are presented to demonstrate the effectiveness of the theoretical results.
167 citations
TL;DR: A new design is presented for globally finite-time stabilising feedback, extending the results obtained in Huang, Lin, and Yang (2005) and may achieve accelerated convergence speed and reduced settling time.
Abstract: Finite-time stability is investigated for a class of nonlinear systems and a new design is presented for globally finite-time stabilising feedback, extending the results obtained in Huang, Lin, and Yang (2005) [‘Global Finite-time Stabilization of a Class of Uncertain Nonlinear Systems’, Automatica, 41, 881–888]. The new method may achieve accelerated convergence speed and reduced settling time. An example verifies the feasibility and effectiveness of the proposed design.
128 citations
TL;DR: The experimental results have demonstrated that the combination of the proposed weighting method called FCMFW and k-NN classifier has obtained very promising results on the classification of PD.
Abstract: This study presents the application of fuzzy c-means (FCM) clustering-based feature weighting (FCMFW) for the detection of Parkinson's disease (PD). In the classification of PD dataset taken from University of California – Irvine machine learning database, practical values of the existing traditional and non-standard measures for distinguishing healthy people from people with PD by detecting dysphonia were applied to the input of FCMFW. The main aims of FCM clustering algorithm are both to transform from a linearly non-separable dataset to a linearly separable one and to increase the distinguishing performance between classes. The weighted PD dataset is presented to k-nearest neighbour (k-NN) classifier system. In the classification of PD, the various k-values in k-NN classifier were used and compared with each other. Also, the effects of k-values in k-NN classifier on the classification of Parkinson disease datasets have been investigated and the best k-value found. The experimental results have demonstr...
102 citations
TL;DR: Building on the theory of finite-time Lyapunov stability, sufficient criteria are proposed which guarantee the system to reach a consensus in finite time, provided that the underlying directed network contains a spanning tree.
Abstract: In this article, we study finite-time state consensus problems for continuous multi-agent systems with nonlinear protocols. Building on the theory of finite-time Lyapunov stability, we propose sufficient criteria which guarantee the system to reach a consensus in finite time, provided that the underlying directed network contains a spanning tree. Novel finite-time consensus protocols are introduced as examples for applying the criteria. Simulations are also presented to illustrate our theoretical results.
96 citations
TL;DR: It is proved that the proposed design method is able to guarantee semi-global uniform ultimate boundedness (SGUUB) of all signals in the closed-loop system.
Abstract: In this article, two robust adaptive control schemes are investigated for a class of completely non-affine pure-feedback non-linear systems with input non-linearity and perturbed uncertainties using radial basis function neural networks (RBFNNs). Based on the dynamic surface control (DSC) technique and using the quadratic Lyapunov function, the explosion of complexity in the traditional backstepping design is avoided when the gain signs are known. In addition, the unknown virtual gain signs are dealt with using the Nussbaum functions. Using the mean value theorem and Young's inequality, only one learning parameter needs to be tuned online at each step of recursion. It is proved that the proposed design method is able to guarantee semi-global uniform ultimate boundedness (SGUUB) of all signals in the closed-loop system. Simulation results verify the effectiveness of the proposed approach.
80 citations
TL;DR: This article is devoted to the consensus control problem of a network of autonomous agents with linear coupling dynamics, subject to external disturbances and communication delays, and proposes a distributed state feedback protocol that is derived from H ∞ theory of linear systems.
Abstract: This article is devoted to the consensus control problem of a network of autonomous agents with linear coupling dynamics, subject to external disturbances and communication delays, and proposes a distributed state feedback protocol. By applying H ∞ theory of linear systems, delay-independent and -dependent conditions in terms of linear matrix inequalities (LMIs) are both derived to ensure consensus of the multi-agent system with a prescribed H ∞ disturbance attenuation index, and the undetermined feedback matrix of the proposed protocol is further solved accordingly. A simulation example is included to validate the theoretical results.
71 citations
TL;DR: A new finite-time synchronised approach is developed for multiple mobile robots formation control based on terminal sliding mode control principle and system synchronisation theory.
Abstract: In this study, a new finite-time synchronised approach is developed for multiple mobile robots formation control based on terminal sliding mode control principle and system synchronisation theory. Associated stability analysis is presented to lay a foundation for analytical understanding in generic theoretical aspects and safe operation for real systems. An illustrative example of multiple mobile robots formation control is bench tested to validate the effectiveness of the proposed approach.
61 citations
TL;DR: In this article, a novel time-delay switched descriptor state observer is proposed to estimate both the state and sensor fault, and an efficient fault-tolerant operation can be realised via sensor fault compensation.
Abstract: In this article, the problems of sensor fault estimation and compensation approaches for time-delay switched systems are investigated based on a switched descriptor observer approach. First, a novel time-delay switched descriptor state observer is proposed to estimate both the state and sensor fault. The proposed observer technique is also extended to systems with nonlinearities. Then, based on the estimation of the sensor fault, an efficient fault-tolerant operation can be realised via sensor fault compensation. Finally, an example is given to show the efficiency of the developed techniques.
59 citations
TL;DR: This study uses both analytic hierarchy process (AHP) and decision-making trial and evaluation laboratory (DEMATEL) methods to evaluate the criteria in auto spare parts industry in Taiwan to improve suppliers’ performance from both short-term and long-term viewpoints.
Abstract: This study uses both analytic hierarchy process AHP and decision-making trial and evaluation laboratory DEMATEL methods to evaluate the criteria in auto spare parts industry in Taiwan. Traditionally, AHP does not consider indirect effects for each criterion and assumes that criteria are independent without further addressing the interdependence between or among the criteria. Thus, the importance computed by AHP can be viewed as short-term improvement opportunity. On the contrary, DEMATEL method not only evaluates the importance of criteria but also depicts the causal relations of criteria. By observing the causal diagrams, the improvement based on cause-oriented criteria might improve the performance effectively and efficiently for the long-term perspective. As a result, the major advantage of integrating AHP and DEMATEL methods is that the decision maker can continuously improve suppliers’ performance from both short-term and long-term viewpoints.
59 citations
TL;DR: A sufficient criterion is presented towards the existence and global asymptotic stability of an equilibrium point (EP), by employing the Leray–Schauder alternative theorem, linear matrix inequality technique and generalised Lyapunov function method.
Abstract: In this article, the issue of global stability is discussed for competitive neural networks with time-varying delay and discontinuous activation functions. First, a sufficient criterion is presented towards the existence and global asymptotic stability of an equilibrium point (EP), by employing the Leray–Schauder alternative theorem, linear matrix inequality technique and generalised Lyapunov function method. In particular, for the case where the activation functions are monotonic increasing, the above criterion also ensures the global exponential stability of an EP. Second, based on the properties of M-matrix, topological degree theory of set-valued map and generalised Lyapunov function method, some sufficient conditions are derived for checking the existence and global exponential stability of an EP. In doing so, the viability problem is investigated and the obtained results are delay-dependent and independent of each other. Finally, two examples with simulations are provided to demonstrate the effectiv...
58 citations
TL;DR: An inventory model for exponentially deteriorating items under conditions of permissible delay in payments is developed to determine the optimal replenishment policies in order to maximise the system's average profit per unit of time.
Abstract: This article develops an inventory model for exponentially deteriorating items under conditions of permissible delay in payments. Unlike the existing related models, we assume that the items are replenished at a finite rate and the demand rate of the items is dependent on the current inventory level. The objective is to determine the optimal replenishment policies in order to maximise the system's average profit per unit of time. A simple method is shown for finding the optimal solution of the model based on the derived properties of the objective function. In addition, we deduce some previously published results as the special cases of the model. Finally, numerical examples are used to illustrate the proposed model. Some managerial insights are also inferred from the sensitive analysis of model parameters.
TL;DR: A pattern recognition method based on grouping by linear relationship a set of faults, using current and force signals in normal-to-reverse and reverse- to-normal directions, for detecting and identifying the faults.
Abstract: This article presents a pattern recognition method based on grouping by linear relationship a set of faults. The majority of faults can be detected, but only a few experiments can be identified. The algorithm called Principal Component Analysis (PCA) is employed together with the statistical parameters of the signals for detecting and identifying the faults. PCA technique is utilised for modifying dataset reducing the coordinate system, which must be correlated, by linear transformation, into a smaller set of uncorrelated variables called ‘principal components’. The signals analysed were the current and force signals in normal-to-reverse and reverse-to-normal directions of the system.
TL;DR: A rigorous performance analysis shows that the distributed fusion algorithm with feedback is also an optimal distributed Kalman filtering fusion algorithm; the P matrices are still the estimate error covariance matrices for local filters; the feedback does reduce the estimateerror covariance of each local filter.
Abstract: In this article, we study the distributed Kalman filtering fusion problem for a linear dynamic system with multiple sensors and cross-correlated noises. For the assumed linear dynamic system, based on the newly constructed measurements whose measurement noises are uncorrelated, we derive a distributed Kalman filtering fusion algorithm without feedback, and prove that it is an optimal distributed Kalman filtering fusion algorithm. Then, for the same linear dynamic system, also based on the newly constructed measurements, a distributed Kalman filtering fusion algorithm with feedback is proposed. A rigorous performance analysis is dedicated to the distributed fusion algorithm with feedback, which shows that the distributed fusion algorithm with feedback is also an optimal distributed Kalman filtering fusion algorithm; the P matrices are still the estimate error covariance matrices for local filters; the feedback does reduce the estimate error covariance of each local filter. Simulation results are provided t...
TL;DR: New delay-dependent stability criteria for linear systems with interval time-varying delays is provided, which has an advantage over some existing ones in the literature due to the fact that it involves fewer matrix variables and is less conservative, which is established theoretically.
Abstract: This article provides new delay-dependent stability criteria for linear systems with interval time-varying delays. With a new Lyapunov–Krasovskii functional constructed, a tighter upper bound of its derivative is estimated. The resulting criterion has an advantage over some existing ones in the literature due to the fact that it involves fewer matrix variables and is less conservative, which is established theoretically. Two numerical examples are given to demonstrate the reduced conservatism of the proposed results.
TL;DR: A price-dependent demand with stochastic selling price into the classical Newsboy problem is introduced and the proposed model analyses the expected average profit for a general distribution function of p and obtains an optimal order size.
Abstract: Up to now, many newsboy problems have been considered in the stochastic inventory literature. Some assume that stochastic demand is independent of selling price (p) and others consider the demand as a function of stochastic shock factor and deterministic sales price. This article introduces a price-dependent demand with stochastic selling price into the classical Newsboy problem. The proposed model analyses the expected average profit for a general distribution function of p and obtains an optimal order size. Finally, the model is discussed for various appropriate distribution functions of p and illustrated with numerical examples.
TL;DR: This article shows that a directed delayed networked multi-agent system can achieve average consensus globally exponentially with suitable impulsive gain and impulsive interval, and proposes a simple impulsive consensus protocol for such networks.
Abstract: In this article, we consider average consensus problem in directed delayed networked multi-agent systems having impulsive effects with fixed topology and stochastic switching topology. A simple impulsive consensus protocol for such networks is proposed, and some generic criteria for solving the average consensus problem are analytically derived. It is shown that a directed delayed networked multi-agent system can achieve average consensus globally exponentially with suitable impulsive gain and impulsive interval. Subsequently, two typical illustrative examples, along with computer simulation results, are provided to visualise the effectiveness and feasibility of our theoretical results.
TL;DR: A new delay-range-dependent bounded real lemma for the solvability of the jump system is obtained based on the Lyapunov–Krasovskii functional, which is in terms of strict linear matrix inequalities (LMIs).
Abstract: The problem of H ∞ filtering for nonlinear singular Markovian jumping systems with interval time-varying delays is investigated. The delay factor is assumed to be time-varying and belongs to a given interval, which means that the lower and upper bounds of the interval time-varying delays are available. Furthermore, the derivative of the time-varying delay function can be larger than one. With partial knowledge of the jump rates of the Markov process, a new delay-range-dependent bounded real lemma for the solvability of the jump system is obtained based on the Lyapunov–Krasovskii functional, which is in terms of strict linear matrix inequalities (LMIs). When these LMIs are feasible, an expression of a desired H ∞ filter is given. Numerical examples are given to illustrate the effectiveness of the developed techniques.
TL;DR: This article considers a single machine scheduling problem with a time-dependent learning effect and deteriorating jobs, and shows that an optimal schedule of the problem is V-shaped with respect to job normal processing times.
Abstract: In this article, we consider a single machine scheduling problem with a time-dependent learning effect and deteriorating jobs. By the effects of time-dependent learning and deterioration, we mean that the job processing time is defined by a function of its starting time and total normal processing time of jobs in front of it in the sequence. The objective is to determine an optimal schedule so as to minimize the total completion time. This problem remains open for the case of −1 < a < 0, where a denotes the learning index; we show that an optimal schedule of the problem is V-shaped with respect to job normal processing times. Three heuristic algorithms utilising the V-shaped property are proposed, and computational experiments show that the last heuristic algorithm performs effectively and efficiently in obtaining near-optimal solutions.
TL;DR: The single-vehicle cyclic inventory routing problem (SV-CIRP) consists of a repetitive distribution of a product from a single depot to a selected subset of customers and an exact algorithm for its solution is proposed.
Abstract: The single-vehicle cyclic inventory routing problem SV-CIRP consists of a repetitive distribution of a product from a single depot to a selected subset of customers. For each customer, selected for replenishments, the supplier collects a corresponding fixed reward. The objective is to determine the subset of customers to replenish, the quantity of the product to be delivered to each and to design the vehicle route so that the resulting profit difference between the total reward and the total logistical cost is maximised while preventing stockouts at each of the selected customers. This problem appears often as a sub-problem in many logistical problems. In this article, the SV-CIRP is formulated as a mixed-integer program with a nonlinear objective function. After a thorough analysis of the structure of the problem and its features, an exact algorithm for its solution is proposed. This exact algorithm requires only solutions of linear mixed-integer programs. Values of a savings-based heuristic for this problem are compared to the optimal values obtained for a set of some test problems. In general, the gap may get as large as 25%, which justifies the effort to continue exploring and developing exact and approximation algorithms for the SV-CIRP.
TL;DR: This article considers the problem of delay-dependent stability analysis for a class of discrete-time singular systems with Markovian jump and time-varying delay and proposesdelay-dependent criteria to ensure the underlying system to be regular, causal and stochastically stable.
Abstract: This article considers the problem of delay-dependent stability analysis for a class of discrete-time singular systems with Markovian jump and time-varying delay. The transition probabilities in Markov chain are assumed to be partially unknown. In terms of linear matrix inequality approach, the delay-dependent criteria are proposed to ensure the underlying system to be regular, causal and stochastically stable. Several numerical examples are given to demonstrate the effectiveness and less conservatism of the obtained results.
TL;DR: This article proposes two new iterative methods for computing the generalised bisymmetric (containing symmetric solution as a special case) and skew-symmetric solutions of the generalising Sylvester matrix equation (including Sylvesters and Lyapunov matrix equations as special cases) which is encountered in many systems and control applications.
Abstract: A matrix P is called a symmetric orthogonal if P = P T = P −1. A matrix X is said to be a generalised bisymmetric with respect to P if X = X T = PXP . It is obvious that any symmetric matrix is also a generalised bisymmetric matrix with respect to I identity matrix. By extending the idea of the Jacobi and the Gauss–Seidel iterations, this article proposes two new iterative methods, respectively, for computing the generalised bisymmetric containing symmetric solution as a special case and skew-symmetric solutions of the generalised Sylvester matrix equation including Sylvester and Lyapunov matrix equations as special cases which is encountered in many systems and control applications. When the generalised Sylvester matrix equation has a unique generalised bisymmetric skew-symmetric solution, the first second iterative method converges to the generalised bisymmetric skew-symmetric solution of this matrix equation for any initial generalised bisymmetric skew-symmetric matrix. Finally, some numerical results are given to illustrate the effect of the theoretical results.
TL;DR: It is shown that there exists a unique optimal policy which minimises the expected cost rate under certain conditions and an approach which using the concept of virtual age is adopted.
Abstract: A system is subject to shocks that arrive according to a non-homogeneous Poisson process. As shocks occur, the system has two types of failures: type 1 failure (minor failure) is removed by a minimal repair, whereas type 2 failure (catastrophic failure) is removed by overhaul or replacement. The cost of minimal repair depends on age. A system is overhauled when the occurrence of a type 2 failure or at age T, whichever occurs first. At the N-th overhaul, the system is replaced rather than overhauled. A maintenance policy for determining optimal number of overhauls and optimal interval between overhauls which incorporate minimal repairs, overhauls and replacement is proposed. Under such a policy, an approach which using the concept of virtual age is adopted. It is shown that there exists a unique optimal policy which minimises the expected cost rate under certain conditions. Various cases are considered.
TL;DR: This article consider the flocking of multi-agents with time delay, and a set of control laws that relies on the state information and the external signal is proposed.
Abstract: This article consider the flocking of multi-agents with time delay. Both leader free and virtual leader available are considered. For leader free, a set of control laws is proposed, and it is proved that the agent velocities become the same asymptotically, and avoidance of collisions between the agents is ensured. For virtual leader available, a set of control laws that relies on the state information and the external signal is proposed. With the control laws all agents can follow the virtual leader.
TL;DR: By decoupling the unknown transition probabilities from the Lyapunov matrices, new sufficient conditions for the H 2 performance analysis of the considered systems are derived in terms of linear matrix inequalities (LMIs).
Abstract: This article addresses the H 2 control problem for continuous Markov jump linear systems with partly known information. The considered partly known transition probabilities cover the cases where the transition probabilities are exactly known, unknown and unknown but with known bounds. By decoupling the unknown transition probabilities from the Lyapunov matrices, new sufficient conditions for the H 2 performance analysis of the considered systems are derived in terms of linear matrix inequalities (LMIs). Based on the result, an LMI-based method for designing H 2 controllers is given. Two numerical examples are presented to illustrate the effectiveness of the proposed methods.
TL;DR: A delay-dependent condition is developed for the existence of the desired state estimator via a novel Lyapunov functional, which has less conservativeness than the existing ones, which is demonstrated by a numerical example.
Abstract: This article deals with the problem of delay-dependent state estimation for discrete-time neural networks with time-varying delay. Our objective is to design a state estimator for the neuron states through available output measurements such that the error state system is guaranteed to be globally exponentially stable. Based on the linear matrix inequality approach, a delay-dependent condition is developed for the existence of the desired state estimator via a novel Lyapunov functional. The obtained condition has less conservativeness than the existing ones, which is demonstrated by a numerical example.
TL;DR: This article considers three basic preventive maintenance policies for a used system: the system with initial variable damage begins to operate at time 0, and suffers damage due to shocks, and optimal policies which minimise them are derived analytically and discussed numerically.
Abstract: In some practical situations, it may be more economical to work a used system than do a new one. From this viewpoint, this article considers three basic preventive maintenance PM policies for a used system: the system with initial variable damage Y 0 begins to operate at time 0, and suffers damage due to shocks. It fails when the total damage exceeds a failure level K and corrective maintenance is made immediately. To prevent such failure, it undergoes PM at a planned time T , a shock number N and a damage level k , but maintenances are imperfect. However, failure rate of a used system maybe higher than that of a new one, so some maintenance is applied to the policies at each shock in the extended models. Using the theory of cumulative processes, expected cost rate models are obtained, optimal policies which minimise them are derived analytically and discussed numerically.
TL;DR: An order-level inventory system for deteriorating items has been developed with demand rate as a function of selling price and the demand and the deterioration rate are price dependent and time proportional, respectively.
Abstract: In this article, an order-level inventory system for deteriorating items has been developed with demand rate as a function of selling price. The demand and the deterioration rate are price dependent and time proportional, respectively. We have considered a perishable item that follows a three-parameter Weibull distribution deterioration. Shortages are not permitted in our model. The optimal solution is illustrated with a numerical example and the sensitivity analysis of parameters is carried out.
TL;DR: This article investigates a memetic computing approach based on particle swarm optimisation for dynamic multi-modal optimisation problems (DMMOPs) and investigates the performance of the proposed algorithm in comparison with several state-of-the-art algorithms taken from the literature.
Abstract: Many real-world optimisation problems are both dynamic and multi-modal, which require an optimisation algorithm not only to find as many optima under a specific environment as possible, but also to track their moving trajectory over dynamic environments. To address this requirement, this article investigates a memetic computing approach based on particle swarm optimisation for dynamic multi-modal optimisation problems DMMOPs. Within the framework of the proposed algorithm, a new speciation method is employed to locate and track multiple peaks and an adaptive local search method is also hybridised to accelerate the exploitation of species generated by the speciation method. In addition, a memory-based re-initialisation scheme is introduced into the proposed algorithm in order to further enhance its performance in dynamic multi-modal environments. Based on the moving peaks benchmark problems, experiments are carried out to investigate the performance of the proposed algorithm in comparison with several state-of-the-art algorithms taken from the literature. The experimental results show the efficiency of the proposed algorithm for DMMOPs.
TL;DR: A generic method for fault detection and isolation in manufacturing systems considered as discrete event systems (DES) is presented, using an identified model of the closed-loop of plant and controller built on the basis of observed fault-free system behaviour.
Abstract: In this article a generic method for fault detection and isolation FDI in manufacturing systems considered as discrete event systems DES is presented. The method uses an identified model of the closed-loop of plant and controller built on the basis of observed fault-free system behaviour. An identification algorithm known from literature is used to determine the fault detection model in form of a non-deterministic automaton. New results of how to parameterise this algorithm are reported. To assess the fault detection capability of an identified automaton, probabilistic measures are proposed. For fault isolation, the concept of residuals adapted for DES is used by defining appropriate set operations representing generic fault symptoms. The method is applied to a case study system.
TL;DR: Two EPQ models of uniform distribution and exponential distribution of corrective and maintenance times are developed and it is shown that the corrective time parameter is one of the most sensitive parameters to the optimal total cost.
Abstract: In recent years, many researches on economic production quantity EPQ models with machine breakdown and preventive maintenance have been developed, but few of them have developed integrated models for deteriorating items. In this study, we develop EPQ models for deteriorating items with preventive maintenance, random machine breakdown and immediate corrective action. Corrective and preventive maintenance times are assumed to be stochastic and the unfulfilled demands are lost sales. Two EPQ models of uniform distribution and exponential distribution of corrective and maintenance times are developed. An example and sensitivity analysis is given to illustrate the models. For the exponential distribution model, it is shown that the corrective time parameter is one of the most sensitive parameters to the optimal total cost.