Discrete Dynamics in Nature and Society http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. New Results on Reachable Set Estimation and Controller Design for Linear Systems with Mixed Delays via Triple Integral Functionals Thu, 02 Jul 2015 09:25:55 +0000 http://www.hindawi.com/journals/ddns/2015/935920/ This paper is concerned with the problem of reachable set estimation and controller design for a class of linear systems with mixed delays and bounded disturbance inputs. By constructing a newly augmented Lyapunov-Krasovskii functional, combining with triple integral technique and reciprocally convex approach, some new reachable set estimation conditions are derived in terms of linear matrix inequalities. Based on these conditions, a state-feedback controller has been designed to ensure the reachable set of the closed-loop system bounded by a given ellipsoid. Finally, two numerical examples are given to illustrate the effectiveness of the proposed analysis and designed method. Wei Kang and Shouming Zhong Copyright © 2015 Wei Kang and Shouming Zhong. All rights reserved. Impulsive Multiorders Riemann-Liouville Fractional Differential Equations Sun, 28 Jun 2015 12:26:18 +0000 http://www.hindawi.com/journals/ddns/2015/603893/ Impulsive multiorders fractional differential equations are studied. Existence and uniqueness results are obtained for first- and second-order impulsive initial value problems by using Banach’s fixed point theorem in an appropriate weighted space. Examples illustrating the main results are presented. Weera Yukunthorn, Sotiris K. Ntouyas, and Jessada Tariboon Copyright © 2015 Weera Yukunthorn et al. All rights reserved. Dynamic Analysis of General Integrated Pest Management Model with Double Impulsive Control Sun, 28 Jun 2015 08:09:16 +0000 http://www.hindawi.com/journals/ddns/2015/839097/ A general predator-prey model with disease in the prey and double impulsive control is proposed and investigated for the purpose of integrated pest management. By using the Floquet theory, the comparison theorem of impulsive differential equations, and the persistence theory of dynamical systems, we obtain that if threshold value , then the susceptible pest eradication periodic solution is globally asymptotically stable and if , then the model is permanent. The numerical examples not only illustrate the theoretical results, but also show that when the model is permanent, then it may possess a unique globally attractive -periodic solution. Yingke Li, Zhidong Teng, Kai Wang, and Ahmadjan Muhammadhaji Copyright © 2015 Yingke Li et al. All rights reserved. A PD-Type Iterative Learning Control for a Class of Switched Discrete-Time Systems with Model Uncertainties and External Noises Thu, 25 Jun 2015 10:57:28 +0000 http://www.hindawi.com/journals/ddns/2015/410292/ A PD-type iterative learning control algorithm is applied to a class of linear discrete-time switched systems for tracking desired trajectories. The application is based on assumption that the switched systems repetitively operate over a finite time interval and the switching rules are arbitrarily prespecified. By taking advantage of the super-vector approach, a sufficient condition of the monotone convergence of the algorithm is deduced when both the model uncertainties and the external noises are absent. Then the robust monotone convergence is analyzed when the model uncertainties are present and the robustness against the bounded external noises is discussed. The analysis manifests that the proposed PD-type iterative learning control algorithm is feasible and effective when it is imposed on the linear switched systems specified by the arbitrarily preset switching rules. The attached simulations support the feasibility and the effectiveness. Xuan Yang Copyright © 2015 Xuan Yang. All rights reserved. Fuzzy Availability Assessment for a Repairable Multistate Series-Parallel System Thu, 25 Jun 2015 10:45:32 +0000 http://www.hindawi.com/journals/ddns/2015/156059/ This paper considers a repairable multistate series-parallel system (RMSSPS) with fuzzy parameters. It is assumed that the system components are independent, and their state transition rates and performance rates are fuzzy values. The fuzzy universal generating function technique is adopted to determine fuzzy state probability and fuzzy performance rate of the system. On the basis of α-cut approach and the extension principle, parametric programming technique is employed to obtain the α-cuts of some indices for the system. The system fuzzy availability is defined as the ability of the system to satisfy fuzzy consumer demand. A special assessment approach is developed for evaluating the fuzzy steady-state availability of the system with the fuzzy demand. A flow transmission system with three components is presented to demonstrate the validity of the proposed method. Linmin Hu, Dequan Yue, and Ruiling Tian Copyright © 2015 Linmin Hu et al. All rights reserved. The Effect of Pulse Vaccination and Treatment on SIR Epidemic Model with Media Impact Thu, 25 Jun 2015 07:13:18 +0000 http://www.hindawi.com/journals/ddns/2015/532494/ We propose a novel SIR epidemic dynamical control model with media impact, where the state dependent pulse vaccination and medication treatment control strategies are being introduced to prevent the spread of disease at different control threshold values. By using the geometry theory of differential equation and method of successor function, the existence of positive order-1 periodic solution is studied. Further, some sufficient conditions of the orbitally asymptotical stability for positive order-1 periodic solution are given by the analog Poincaré criterion. Furthermore, numerical simulations are carried to illustrate the feasibility of our main results presented here. Zhi-Long He and Lin-Fei Nie Copyright © 2015 Zhi-Long He and Lin-Fei Nie. All rights reserved. Stabilization of the FO-BLDCM Chaotic System in the Sense of Lyapunov Tue, 23 Jun 2015 05:57:17 +0000 http://www.hindawi.com/journals/ddns/2015/750435/ Based on an integer-order Brushless DC motors (IO-BLDCM) system, we give a fractional-order Brushless DC motors (FO-BLDCM) system in this paper. There exists a chaotic attractor for fractional-order in the FO-BLDCM system. Furthermore, using the Lyapunov direct method for fractional-order system, a control scheme is proposed to stabilize the FO-BLDCM chaotic system in the sense of Lyapunov. Numerical simulation shows that the control scheme in this paper is valid for the FO-BLDCM chaotic system. Ping Zhou, Rongji Bai, and Hao Cai Copyright © 2015 Ping Zhou et al. All rights reserved. Simulation of a Vibrant Membrane Using a 2-Dimensional Cellular Automaton Thu, 18 Jun 2015 11:51:16 +0000 http://www.hindawi.com/journals/ddns/2015/542507/ This paper proposes a 2-dimensional cellular automaton (CA) model and how to derive the model evolution rule to simulate a two-dimensional vibrant membrane. The resulting model is compared with the analytical solution of a two-dimensional hyperbolic partial differential equation (PDE), linear and homogeneous. This models a vibrant membrane with specific conditions, initial and boundary. The frequency spectrum is analysed as well as the error between the data produced by the CA model. Then it is compared to the data provided by the solution evaluation to the differential equation. This shows how the CA obtains a behavior similar to the PDE. Moreover, it is possible to simulate nonclassical initial conditions for which there is no exact solution using PDE. Very interesting information could be obtained from the CA model such as the fundamental frequency. I. Huerta-Trujillo, J. C. Chimal-Eguía, L. Muñoz-Salazar, and J. A. Martinez-Nuño Copyright © 2015 I. Huerta-Trujillo et al. All rights reserved. Random Vibration Analysis of Train Moving over Slab Track on Bridge under Track Irregularities and Earthquakes by Pseudoexcitation Method Wed, 17 Jun 2015 12:55:59 +0000 http://www.hindawi.com/journals/ddns/2015/436567/ This paper investigates the random vibration and the dynamic reliability of operation stability of train moving over slab track on bridge under track irregularities and earthquakes by the pseudoexcitation method (PEM). Each vehicle is modeled by multibody dynamics. The track and bridge is simulated by a rail-slab-girder-pier interaction finite element model. The coupling equations of motion are established based on the wheel-rail interaction relationship. The random excitations of the track irregularities and seismic accelerations are transformed into a series of deterministic pseudoexcitations by PEM. The time-dependent power spectral densities (PSDs) of the random vibration of the system are obtained by step-by-step integration method, and the corresponding dynamic reliability is estimated based on the first-passage failure criterion. A case study is then presented in which a high-speed train moves over a slab track resting on a simply supported girder bridge. The PSD characteristics of the random vibration of the bridge and train are analyzed, the influence of the wheel-rail-bridge interaction models on the random vibration of the bridge and train is discussed, and furthermore the influence of train speed, earthquake intensity, and pier height on the dynamic reliability of train operation stability is studied. Zhiping Zeng, Kunteng Zhu, Xianfeng He, Wentao Xu, Lingkun Chen, and Ping Lou Copyright © 2015 Zhiping Zeng et al. All rights reserved. A Mathematical Model of the Formation of Lanes in Crowds of Pedestrians Moving in Opposite Directions Wed, 17 Jun 2015 12:48:32 +0000 http://www.hindawi.com/journals/ddns/2015/872807/ In crowded environments, pedestrians moving in opposite directions segregate into lanes of individuals moving in the same direction. It is believed that this formation of lanes that facilitates the flow results from the individuals acting on their behalf, responding to local stimuli, without the intention of benefiting the crowd as a whole. We give evidence that this is true by developing and analyzing a simple mathematical model. Our results suggest that the simple behavior of moving out of the way to avoid imminent collisions leads to the formation of lanes of individuals moving in the same direction. Guillermo H. Goldsztein Copyright © 2015 Guillermo H. Goldsztein. All rights reserved. Multilevel Bloom Filters for P2P Flows Identification Based on Cluster Analysis in Wireless Mesh Network Tue, 16 Jun 2015 09:40:50 +0000 http://www.hindawi.com/journals/ddns/2015/801934/ With the development of wireless mesh networks and distributed computing, lots of new P2P services have been deployed and enrich the Internet contents and applications. The rapid growth of P2P flows brings great pressure to the regular network operation. So the effective flow identification and management of P2P applications become increasingly urgent. In this paper, we build a multilevel bloom filters data structure to identify the P2P flows through researches on the locality characteristics of P2P flows. Different level structure stores different numbers of P2P flow rules. According to the characteristics values of the P2P flows, we adjust the parameters of the data structure of bloom filters. The searching steps of the scheme traverse from the first level to the last level. Compared with the traditional algorithms, our method solves the drawbacks of previous schemes. The simulation results demonstrate that our algorithm effectively enhances the performance of P2P flows identification. Then we deploy our flow identification algorithm in the traffic monitoring sensors which belong to the network traffic monitoring system at the export link in the campus network. In the real environment, the experiment results demonstrate that our algorithm has a fast speed and high accuracy to identify the P2P flows; therefore, it is suitable for actual deployment. Xia-an Bi, Xiaohui Wang, Luyun Xu, Sheng Chen, and Hong Liu Copyright © 2015 Xia-an Bi et al. All rights reserved. Stabilizing Solution for a Discrete-Time Modified Algebraic Riccati Equation in Infinite Dimensions Tue, 16 Jun 2015 08:24:12 +0000 http://www.hindawi.com/journals/ddns/2015/293930/ We provide necessary and sufficient conditions for the existence of stabilizing solutions for a class of modified algebraic discrete-time Riccati equations (MAREs) defined on ordered Banach spaces of sequences of linear and bounded operators. These MAREs arise in the study of linear quadratic (LQ) optimal control problems for infinite-dimensional discrete-time linear systems (DTLSs) affected simultaneously by multiplicative white noise (MN) and Markovian jumps (MJs). Unlike most of the previous works, where the detectability and observability notions are key tools for studying the global solvability of MAREs, in this paper the conditions of existence of mean-square stabilizing solutions are given directly in terms of system parameters. The methods we have used are based on the spectral theory of positive operators and the properties of trace class and compact operators. Our results generalise similar ones obtained for finite-dimensional MAREs associated with stochastic DTLSs without MJs. Also they complete and extend (in the autonomous case) former investigations concerning the existence of certain global solutions (as minimal, maximal, and stabilizing solutions) for generalized discrete-time Riccati type equations defined on infinite-dimensional ordered Banach spaces. Viorica Mariela Ungureanu Copyright © 2015 Viorica Mariela Ungureanu. All rights reserved. Multiscale Discrete Simulation of Complex Systems Tue, 16 Jun 2015 08:08:44 +0000 http://www.hindawi.com/journals/ddns/2015/383084/ Qingang Xiong, Jingsen Ma, Hao Zhou, and Giulio Lorenzini Copyright © 2015 Qingang Xiong et al. All rights reserved. On Global Attractors for a Class of Reaction-Diffusion Equations on Unbounded Domains with Some Strongly Nonlinear Weighted Term Sun, 14 Jun 2015 12:32:11 +0000 http://www.hindawi.com/journals/ddns/2015/251614/ We consider the existence and properties of the global attractor for a class of reaction-diffusion equation ,  in  ;  ,  in  . Under some suitable assumptions, we first prove that the problem has a global attractor in . Then, by using the -index theory, we verify that is an infinite dimensional set and it contains infinite distinct pairs of equilibrium points. Jin Zhang and Chengkui Zhong Copyright © 2015 Jin Zhang and Chengkui Zhong. All rights reserved. Mathematical Development and Evaluation of Forecasting Models for Accuracy of Inflation in Developing Countries: A Case of Vietnam Thu, 11 Jun 2015 07:41:01 +0000 http://www.hindawi.com/journals/ddns/2015/858157/ Inflation is a key element of a national economy, and it is also a prominent and important issue influencing the whole economy in terms of marketing. This is a complex problem requiring a large investment of time and wisdom to attain positive results. Thus, appropriate tools for forecasting inflation variables are crucial significant for policy making. In this study, both clarified value calculation and use of a genetic algorithm to find the optimal parameters are adopted simultaneously to construct improved models: ARIMA, GM(1,1), Verhulst, DGM(1,1), and DGM(2,1) by using data of Vietnamese inflation output from January 2005 to November 2013. The MAPE, MSE, RMSE, and MAD are four criteria with which the various forecasting models results are compared. Moreover, to see whether differences exist, Friedman and Wilcoxon tests are applied. Both in-sample and out-of-sample forecast performance results show that the ARIMA model has highly accurate forecasting in Raw Materials Price (RMP) and Gold Price (GP), whereas, the calculated results of GM(1,1) and DGM(1,1) are suitable to forecast Consumer Price Index (CPI). Therefore, the ARIMA, GM(1,1), and DGM(1,1) can handle the forecast accuracy of the issue, and they are suitable in modeling and forecasting of inflation in the case of Vietnam. Nhu-Ty Nguyen and Thanh-Tuyen Tran Copyright © 2015 Nhu-Ty Nguyen and Thanh-Tuyen Tran. All rights reserved. Stability and Convergence of Solutions to Volterra Integral Equations on Time Scales Wed, 10 Jun 2015 13:41:38 +0000 http://www.hindawi.com/journals/ddns/2015/612156/ We consider Volterra integral equations on time scales and present our study about the long time behavior of their solutions. We provide sufficient conditions for the stability and investigate the convergence properties when the kernel of the equations vanishes at infinity. Eleonora Messina and Antonia Vecchio Copyright © 2015 Eleonora Messina and Antonia Vecchio. All rights reserved. Research on the Development Approach for Reusable Model in Parallel Discrete Event Simulation Wed, 10 Jun 2015 13:31:38 +0000 http://www.hindawi.com/journals/ddns/2015/580328/ Model reuse is an essential means to meet the demand of model development in complex simulation. An effective approach to realize the model reusability is to establish standard model specification including interface specification and representation specification. By standardizing model’s external interfaces, Reusable Component Model Framework (RCMF) achieves the model reusability acting as an interface specification. However, the RCMF model is presently developed just through manual programing. Besides implementing model’s business logic, modeler should also ensure the model strictly following the reusable framework, which is very distracting. And there lacks model description information for instructing model reuse or integration. To address these issues, we first explored an XML-based model description file which completed RCMF as the model representation and then proposed a RCMF model development tool—SuKit. Model description file describes a RCMF model and can be used for regenerating a model and instructing model integration. SuKit can generate a skeleton RCMF model together with a model-customized description file with the configured information. Modeler then just needs to concentrate on the model processing logic. The case study indicates that SuKit has good capability of developing RCMF models and the well-formed description file can be used for model reuse and integration. Jianbo Li, Yiping Yao, Wenjie Tang, and Feng Zhu Copyright © 2015 Jianbo Li et al. All rights reserved. Dynamics of a Discrete Host-Parasitoid System with Stocking Wed, 10 Jun 2015 06:56:36 +0000 http://www.hindawi.com/journals/ddns/2015/905957/ Motivated by the biological control of pests, we present discrete-time models of host-parasitoid interactions to study the effects of external stocking upon the systems. It is assumed that density dependence of the hosts occurs first followed by parasitism. We prove that the constant stocking can eliminate the pest population if the stocking is sufficiently large. Furthermore, stocking can simplify the dynamics of the interaction by stabilizing the coexisting steady state. Sophia R.-J. Jang Copyright © 2015 Sophia R.-J. Jang. All rights reserved. Nonautonomous Discrete Neuron Model with Multiple Periodic and Eventually Periodic Solutions Wed, 10 Jun 2015 06:33:38 +0000 http://www.hindawi.com/journals/ddns/2015/147282/ We introduce a nonautonomous discrete neuron model based on the Rulkov map and investigate its dynamics. Using both the linear stability and bifurcation analyses of the system of piecewise difference equations, we determine dynamical bifurcations and parameter regions of steady-state and periodic solutions. Alexander N. Pisarchik, Michael A. Radin, and Ryan Vogt Copyright © 2015 Alexander N. Pisarchik et al. All rights reserved. Stability Analysis and Design of a Nonlinear Controller for Hot Rolling Coiler Tue, 09 Jun 2015 14:28:42 +0000 http://www.hindawi.com/journals/ddns/2015/938287/ For the new style hot rolling coiler which adopt AC asynchronous motor as the driving force and with using the algorithm based on differential geometry design nonlinear controller, precise coiling tension control in the rolling process of strip steel is achieved. In this paper, under the rotating orthogonal coordinate system, the fifth-order nonlinear motor model is selected as the controlled plant. By multi-input multioutput (MIMO) exact feedback linearization (EFL) algorithm, the nonlinear model is transformed to a linear one. In terms of small-gain theorem, it is the first to prove that the nonlinear coiler engine that contains the controller has characteristics of input-to-state stability. Experimental results show that the algorithm can be used for high order tracking control system with time-varying parameters. Even without the traditional flux orientation calculation, the output signals are decoupled. With this controller, the tension deviation is restricted to less than 3% and average rotational speed bias was decreased from 0.5% to 0.1% that ensure high-quality plate cut and surface of strip products. Rui Li, Chao-nan Tong, and Xu Yang Copyright © 2015 Rui Li et al. All rights reserved. Algorithms for Routing Optimization in Multipoint to Multipoint 4PL System Tue, 09 Jun 2015 13:57:16 +0000 http://www.hindawi.com/journals/ddns/2015/426947/ Fourth party logistics (4PL) has been receiving great attention and studied by researchers. This paper studies multipoint to multipoint 4PL system routing optimization with reliability constraints. Objective factors which cause disturbances of transportation time are taken into consideration. The mathematical model of the multipoint to multipoint multitask routing optimization in 4PL system with reliability constraints is set up. To solve the model, a Messy Genetic Algorithm (Messy GA) with double arrays encoding method is designed. The experimental result is compared with the Enumeration Algorithm (EA), and it shows that this algorithm can find the satisfactory solution and is a powerful optimization method for solving the problem. Jia Li, Yanqiu Liu, Ying Zhang, and Shida Xu Copyright © 2015 Jia Li et al. All rights reserved. Dynamic Modeling and Optimal Control for Complex Systems with Statistical Trajectory Tue, 09 Jun 2015 13:32:18 +0000 http://www.hindawi.com/journals/ddns/2015/245685/ This paper is concerned with the problem of the working state class dynamic modeling and control of the complex system with statistical trajectory. Firstly, a novel discrete-time nonlinear working state class dynamic mathematical model of sintering machine is constructed by -means cluster method for the local data, which overcomes difficulties of modeling by mechanism and describes the class change against the point movement. Then, based on the working state class dynamic modeling, the optimal control method which is significant to achieve trajectory tracking for sintering machine is developed by constructing the quadratic performance indicator. More importantly, the method facilitates control process realization from one class to another. Finally, the simulation is provided to illustrate the effectiveness of the proposed method. Lingli Guo, Zhengguang Xu, and Ye Wang Copyright © 2015 Lingli Guo et al. All rights reserved. Cognitive Emotional Regulation Model in Human-Robot Interaction Tue, 09 Jun 2015 13:28:44 +0000 http://www.hindawi.com/journals/ddns/2015/829387/ This paper integrated Gross cognitive process into the HMM (hidden Markov model) emotional regulation method and implemented human-robot emotional interaction with facial expressions and behaviors. Here, energy was the psychological driving force of emotional transition in the cognitive emotional model. The input facial expression was translated into external energy by expression-emotion mapping. Robot’s next emotional state was determined by the cognitive energy (the stimulus after cognition) and its own current emotional energy’s size and source’s position. The two random quantities in emotional transition process—the emotional family and the specific emotional state in the AVS (arousal-valence-stance) 3D space—were used to simulate human emotion selection. The model had been verified by an emotional robot with 10 degrees of freedom and more than 100 kinds of facial expressions. Experimental results show that the emotional regulation model does not simply provide the typical classification and jump in terms of a set of emotional labels but that it operates in a 3D emotional space enabling a wide range of intermediary emotional states to be obtained. So the robot with cognitive emotional regulation model is more intelligent and real; moreover it can give full play to its emotional diversification in the interaction. Xin Liu, Lun Xie, Anqi Liu, and Dan Li Copyright © 2015 Xin Liu et al. All rights reserved. Forecasting Beijing Transportation Hub Areas’s Pedestrian Flow Using Modular Neural Network Tue, 09 Jun 2015 13:16:05 +0000 http://www.hindawi.com/journals/ddns/2015/749181/ Along with the increasing proportion of urban public transportation trip, pedestrian flow in transportation hub areas increased. For effectively improving the emergency handling ability of related management apartments and preventing the incident of pedestrian congestion, this paper studied the method of pedestrian flow forecast in Beijing transportation hub areas. Firstly, 34 typical sidewalks in Beijing transportation hub areas were surveyed to obtain 2200 valid data. Secondly, correlation analysis was used to analyze the relationship between pedestrian flow and its influential factors. 11 significant influential factors were extracted. Thirdly, forecasting model was established with modular neural network. The surveyed pedestrian flow sample was fuzzy clustered according to the regional land use where the transportation hub existed. Then, membership function based on the distance measure was constructed. Through fuzzy discrimination, online selection for the subnetwork of the information can be achieved. Consequently, the self-adaptation of the neural network on information processing was improved. Finally, this paper tested the pedestrian flow sample of a transportation hub in Beijing. It was concluded that the accuracy of pedestrian flow forecasting model using modular neural network was higher than other neural network models. There was also improvement in the adaptability to environment. Shuwei Wang, Ronggui Zhou, and Lin Zhao Copyright © 2015 Shuwei Wang et al. All rights reserved. System Dynamics Simulation of Large-Scale Generation System for Designing Wind Power Policy in China Tue, 09 Jun 2015 13:14:05 +0000 http://www.hindawi.com/journals/ddns/2015/475461/ This paper focuses on the impacts of renewable energy policy on a large-scale power generation system, including thermal power, hydropower, and wind power generation. As one of the most important clean energy, wind energy has been rapidly developed in the world. But in recent years there is a serious waste of wind power equipment and investment in China leading to many problems in the industry from wind power planning to its integration. One way overcoming the difficulty is to analyze the influence of wind power policy on a generation system. This paper builds a system dynamics (SD) model of energy generation to simulate the results of wind energy generation policies based on a complex system. And scenario analysis method is used to compare the effectiveness and efficiency of these policies. The case study shows that the combinations of lower portfolio goal and higher benchmark price and those of higher portfolio goal and lower benchmark price have large differences in both effectiveness and efficiency. On the other hand, the combinations of uniformly lower or higher portfolio goal and benchmark price have similar efficiency, but different effectiveness. Finally, an optimal policy combination can be chosen on the basis of policy analysis in the large-scale power system. Linna Hou Copyright © 2015 Linna Hou. All rights reserved. Automation Countermeasure System for Intersection Optimization Tue, 09 Jun 2015 13:10:57 +0000 http://www.hindawi.com/journals/ddns/2015/893872/ To satisfy the demand of congestion problem solving in intersections, this paper studies the method of automation countermeasure system for intersection optimization (ACSIO). Taking into account the extensive contents and objectives of intersection optimization, this paper puts forward the functions and architecture of ACSIO based on intersection optimization problem statement. Seeking optimal design of intersection channelization and signal control, the main goal of ACSIO is to achieve dynamic and coordination management of intersection. The problem is formulated as a multiobjective program, with each objective corresponding to a different player in the system. Moreover, it presents system design of ACSIO. A case study based on a real-world intersection is implemented to test the efficiency and applicability of the proposed modeling and computing methods. Hua-pu Lu, Zhi-yuan Sun, Wen-cong Qu, and Yue Li Copyright © 2015 Hua-pu Lu et al. All rights reserved. Existence and Convergence of the Positive Solutions of a Discrete Epidemic Model Thu, 04 Jun 2015 08:12:02 +0000 http://www.hindawi.com/journals/ddns/2015/434537/ We consider a class of system of nonlinear difference equations arising from mathematical models describing a discrete epidemic model. Sufficient conditions are established that guarantee the existence of positive solutions, the existence of a unique nonnegative equilibrium, and the convergence of the positive solutions to the nonnegative equilibrium of the system of difference equations. The obtained results are new and they complement previously known results. Zhijian Wei and Meitao Le Copyright © 2015 Zhijian Wei and Meitao Le. All rights reserved. Hybrid Dynamic Network Data Envelopment Analysis Thu, 04 Jun 2015 07:10:06 +0000 http://www.hindawi.com/journals/ddns/2015/989581/ Conventional DEA models make no hypothesis concerning the internal operations in a static situation. To open the “black box” and work with dynamic assessment issues synchronously, we put forward a hybrid model for evaluating the relative efficiencies of a set of DMUs over an observed time period with a composite of network DEA and dynamic DEA. We vertically deal with intermediate products between divisions with assignable inputs in the network structure and, horizontally, we extend network structure by means of a dynamic pattern with unrelated activities between two succeeding periods. The hybrid dynamic network DEA model proposed in this paper enables us to (i) pry into the internal operations of DEA by another network structure, (ii) obtain dynamic change of period efficiency, and (iii) gain the overall dynamic efficiency of DMUs over the entire observed periods. We finally illustrate the calculation procedure of the proposed approach by a numerical example. Ling Li and Fengshan Wang Copyright © 2015 Ling Li and Fengshan Wang. All rights reserved. Modeling and Verification of Reconfigurable and Energy-Efficient Manufacturing Systems Tue, 02 Jun 2015 06:14:41 +0000 http://www.hindawi.com/journals/ddns/2015/813476/ This paper deals with the formal modeling and verification of reconfigurable and energy-efficient manufacturing systems (REMSs) that are considered as reconfigurable discrete event control systems. A REMS not only allows global reconfigurations for switching the system from one configuration to another, but also allows local reconfigurations on components for saving energy when the system is in a particular configuration. In addition, the unreconfigured components of such a system should continue running during any reconfiguration. As a result, during a system reconfiguration, the system may have several possible paths and may fail to meet control requirements if concurrent reconfiguration events and normal events are not controlled. To guarantee the safety and correctness of such complex systems, formal verification is of great importance during a system design stage. This paper extends the formalism reconfigurable timed net condition/event systems (R-TNCESs) in order to model all possible dynamic behavior in such systems. After that, the designed system based on extended R-TNCESs is verified with the help of a software tool SESA for functional, temporal, and energy-efficient properties. This paper is illustrated by an automatic assembly system. Jiafeng Zhang, Mohamed Khalgui, Wassim Mohamed Boussahel, Georg Frey, ChiTin Hon, Naiqi Wu, and Zhiwu Li Copyright © 2015 Jiafeng Zhang et al. All rights reserved. A New Approach to Global Stability of Discrete Lotka-Volterra Predator-Prey Models Mon, 01 Jun 2015 11:57:29 +0000 http://www.hindawi.com/journals/ddns/2015/674027/ An Euler difference scheme for a three-dimensional predator-prey model is considered and we introduce a new approach to show the global stability of the scheme. For this purpose, we partition the three-dimensional space and calculate the sign of the rate change of population of species in each partitioned region. Our method is independent of dimension and then can be applicable to other dimensional discrete models. Numerical examples are presented to verify the results in this paper. Young-Hee Kim and Sangmok Choo Copyright © 2015 Young-Hee Kim and Sangmok Choo. All rights reserved.