Discrete Dynamics in Nature and Society http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Stability Analysis of a System of Exponential Difference Equations Thu, 24 Jul 2014 08:08:56 +0000 http://www.hindawi.com/journals/ddns/2014/375890/ We study the boundedness character and persistence, existence and uniqueness of positive equilibrium, local and global behavior, and rate of convergence of positive solutions of the following system of exponential difference equations: , , where the parameters , and for and initial conditions , and are positive real numbers. Furthermore, by constructing a discrete Lyapunov function, we obtain the global asymptotic stability of the positive equilibrium. Some numerical examples are given to verify our theoretical results. Q. Din, K. A. Khan, and A. Nosheen Copyright © 2014 Q. Din et al. All rights reserved. Note on the Persistence of a Nonautonomous Lotka-Volterra Competitive System with Infinite Delay and Feedback Controls Thu, 24 Jul 2014 07:03:03 +0000 http://www.hindawi.com/journals/ddns/2014/682769/ We study a nonautonomous Lotka-Volterra competitive system with infinite delay and feedback controls. We establish a series of criteria under which a part of -species of the systems is driven to extinction while the remaining part of the species is persistent. Particularly, as a special case, a series of new sufficient conditions on the persistence for all species of system are obtained. Several examples together with their numerical simulations show the feasibility of our main results. Chunling Shi, Yiqin Wang, Xiaoying Chen, and Yuli Chen Copyright © 2014 Chunling Shi et al. All rights reserved. Improvement of Power Flow Calculation with Optimization Factor Based on Current Injection Method Thu, 24 Jul 2014 00:00:00 +0000 http://www.hindawi.com/journals/ddns/2014/437567/ This paper presents an improvement in power flow calculation based on current injection method by introducing optimization factor. In the method proposed by this paper, the PQ buses are represented by current mismatches while the PV buses are represented by power mismatches. It is different from the representations in conventional current injection power flow equations. By using the combined power and current injection mismatches method, the number of the equations required can be decreased to only one for each PV bus. The optimization factor is used to improve the iteration process and to ensure the effectiveness of the improved method proposed when the system is ill-conditioned. To verify the effectiveness of the method, the IEEE test systems are tested by conventional current injection method and the improved method proposed separately. Then the results are compared. The comparisons show that the optimization factor improves the convergence character effectively, especially that when the system is at high loading level and R/X ratio, the iteration number is one or two times less than the conventional current injection method. When the overloading condition of the system is serious, the iteration number in this paper appears 4 times less than the conventional current injection method. Lei Wang, Chen Chen, and Tao Shen Copyright © 2014 Lei Wang et al. All rights reserved. Research on MAS-Based Supply Chain Resilience and Its Self-Organized Criticality Wed, 23 Jul 2014 11:40:12 +0000 http://www.hindawi.com/journals/ddns/2014/621341/ Building resilient supply chain is an effective way to deal with uncertain risks. First, by analyzing the self-organization of supply chain, the supply chain resilience is described as a macroscopic property that generates from self-organizing behavior of each enterprise on the microlevel. Second, a MAS-based supply chain resilience model is established and its local fitness function, neighborhood structure, and interaction rules that are applicable to supply chain system are designed through viewing the enterprise as an agent. Finally, with the help of a case, we find that there is an agglomeration effect and a SOC characteristic in supply chain and the evolution of supply chain is controlled by parameters of MAS. Managers can control the supply chain within the resilient range and choose a good balance between interest and risk by controlling enterprises’ behavior. Liang Geng, Renbin Xiao, and Xing Xu Copyright © 2014 Liang Geng et al. All rights reserved. Functional Principal Components Analysis of Shanghai Stock Exchange 50 Index Tue, 22 Jul 2014 11:35:22 +0000 http://www.hindawi.com/journals/ddns/2014/365204/ The main purpose of this paper is to explore the principle components of Shanghai stock exchange 50 index by means of functional principal component analysis (FPCA). Functional data analysis (FDA) deals with random variables (or process) with realizations in the smooth functional space. One of the most popular FDA techniques is functional principal component analysis, which was introduced for the statistical analysis of a set of financial time series from an explorative point of view. FPCA is the functional analogue of the well-known dimension reduction technique in the multivariate statistical analysis, searching for linear transformations of the random vector with the maximal variance. In this paper, we studied the monthly return volatility of Shanghai stock exchange 50 index (SSE50). Using FPCA to reduce dimension to a finite level, we extracted the most significant components of the data and some relevant statistical features of such related datasets. The calculated results show that regarding the samples as random functions is rational. Compared with the ordinary principle component analysis, FPCA can solve the problem of different dimensions in the samples. And FPCA is a convenient approach to extract the main variance factors. Zhiliang Wang, Yalin Sun, and Peng Li Copyright © 2014 Zhiliang Wang et al. All rights reserved. Analysis on the Impact of the Fluctuation of the International Gold Prices on the Chinese Gold Stocks Mon, 21 Jul 2014 12:02:07 +0000 http://www.hindawi.com/journals/ddns/2014/308626/ Five gold stocks in Chinese Shanghai and Shenzhen A-share and Comex gold futures are chosen to form the sample, for the purpose of analysing the impact of the fluctuation of the international gold prices on the gold stocks in Chinese Shanghai and Shenzhen A-share. Using the methods of unit root test, Granger causality test, VAR model, and impulse response function, this paper has analysed the relationship between the price change of the international gold futures and the price fluctuation of gold stocks in Chinese Shanghai and Shenzhen comprehensively. The results suggest the fluctuation of the international gold futures has a strong influence on the domestic futures. Jiankang Jin, Chen Jie, and Quanda Zhang Copyright © 2014 Jiankang Jin et al. All rights reserved. Lyapunov Functions for a Class of Discrete SIRS Epidemic Models with Nonlinear Incidence Rate and Varying Population Sizes Mon, 21 Jul 2014 08:44:34 +0000 http://www.hindawi.com/journals/ddns/2014/472746/ We investigate the dynamical behaviors of a class of discrete SIRS epidemic models with nonlinear incidence rate and varying population sizes. The model is required to possess different death rates for the susceptible, infectious, recovered, and constant recruitment into the susceptible class, infectious class, and recovered class, respectively. By using the inductive method, the positivity and boundedness of all solutions are obtained. Furthermore, by constructing new discrete type Lyapunov functions, the sufficient and necessary conditions on the global asymptotic stability of the disease-free equilibrium and endemic equilibrium are established. Ying Wang, Zhidong Teng, and Mehbuba Rehim Copyright © 2014 Ying Wang et al. All rights reserved. Local Fractional Laplace Variational Iteration Method for Solving Linear Partial Differential Equations with Local Fractional Derivative Thu, 17 Jul 2014 09:19:00 +0000 http://www.hindawi.com/journals/ddns/2014/365981/ The local fractional Laplace variational iteration method was applied to solve the linear local fractional partial differential equations. The local fractional Laplace variational iteration method is coupled by the local fractional variational iteration method and Laplace transform. The nondifferentiable approximate solutions are obtained and their graphs are also shown. Ai-Min Yang, Jie Li, H. M. Srivastava, Gong-Nan Xie, and Xiao-Jun Yang Copyright © 2014 Ai-Min Yang et al. All rights reserved. Estimation of the Treatment Effects of Ownership on the Indirect Financing of Small- and Medium-Sized Enterprises Wed, 16 Jul 2014 12:04:48 +0000 http://www.hindawi.com/journals/ddns/2014/453458/ Small- and medium-sized enterprises (SMEs) are the important driving forces for the growth of China’s economy. However, financing difficulty has always been the important problem besetting the development of SMEs for a long time. In particular, in recent years, US subprime crisis in 2008 caused a heavy blow to the development of some externally oriented SMEs. Thus, how to effectively overcome financing predicament for the SMEs is crucial for Chinese government. In this paper, based on microdata from China Industrial Enterprise Database, propensity score matching (PSM) method is adopted to conduct empirical analysis about the treatment effects of indirect financing level of SMEs under different systems. Empirical results reveal that state-owned enterprises enjoy indirect financing advantages compared with other enterprises and there is certain ownership discrimination against foreign-funded enterprises and private enterprises. In particular, the indirect financing rate of state-owned enterprises is 1.4% higher than that of other enterprises, and the indirect financing rate of foreign-funded enterprises is 6% lower than that of other enterprises; private enterprises are advantageous in indirect financing compared with other enterprises; however, indirect financing rate of private enterprises is 1.8% lower than that of state-owned enterprises, which also reveals ownership discrimination to certain extent. Xiuzhen Wang, Yi Hu, Xiaohua Xia, and Ying Deng Copyright © 2014 Xiuzhen Wang et al. All rights reserved. An Extended SISa Model for Sentiment Contagion Wed, 16 Jul 2014 08:02:38 +0000 http://www.hindawi.com/journals/ddns/2014/262384/ One of the main differences between sentiment and infectious diseases is that the former one has two opposite infectious states: positive (optimistic) and negative (pessimistic), while the latter one has not. In this paper, based on the SISa model, we consider this issue and propose a new model of sentiment contagion called the SOSa-SPSa model. The results of both numerical and agent-based simulations show that our model could explain the process of sentiment contagion better than that of Hill et al. (2010). Further analysis shows that both the numbers of optimistic and pessimistic individuals will increase with the probability of spontaneity or contagion and decrease with the probability of recovery. Potential applications of this model in financial market have also been discussed. Zhifeng Liu, Tingting Zhang, and Qiujun Lan Copyright © 2014 Zhifeng Liu et al. All rights reserved. Pricing Options Based on Trinomial Markov Tree Wed, 16 Jul 2014 07:31:26 +0000 http://www.hindawi.com/journals/ddns/2014/624360/ A trinomial Markov tree model is studied for pricing options in which the dynamics of the stock price are modeled by the first-order Markov process. Firstly, we construct a trinomial Markov tree with recombining nodes. Secondly, we give an algorithm for estimating the risk-neutral probability and provide the condition for the existence of a validation risk-neutral probability. Thirdly, we propose a method for estimating the volatilities. Lastly, we analyze the convergence and sensitivity of the pricing method implementing trinomial Markov tree. The result shows that, compared to binomial Markov tree, the proposed model is a natural combining tree and, while changing the probability of the node, it is still combining, so the computation is very fast and very easy to be implemented. Hu Xiaoping, Guo Jiafeng, Du Tao, Cui Lihua, and Cao Jie Copyright © 2014 Hu Xiaoping et al. All rights reserved. Canard Limit Cycle of the Holling-Tanner Model Wed, 16 Jul 2014 00:00:00 +0000 http://www.hindawi.com/journals/ddns/2014/856475/ By using the singular perturbation theory on canard cycles, we investigate the canard phenomenon for the Holling-Tanner model with the intrinsic growth rate of the predator small enough. The obtained result shows that there may be at most one canard limit cycle, and the range of small parameters is estimated. The phenomenon of outbreak is explained. Chongwu Zheng, Fengqin Zhang, and Jianquan Li Copyright © 2014 Chongwu Zheng et al. All rights reserved. Joint Optimal Production Planning for Complex Supply Chains Constrained by Carbon Emission Abatement Policies Wed, 16 Jul 2014 00:00:00 +0000 http://www.hindawi.com/journals/ddns/2014/361923/ We focus on the joint production planning of complex supply chains facing stochastic demands and being constrained by carbon emission reduction policies. We pick two typical carbon emission reduction policies to research how emission regulation influences the profit and carbon footprint of a typical supply chain. We use the input-output model to capture the interrelated demand link between an arbitrary pair of two nodes in scenarios without or with carbon emission constraints. We design optimization algorithm to obtain joint optimal production quantities combination for maximizing overall profit under regulatory policies, respectively. Furthermore, numerical studies by featuring exponentially distributed demand compare systemwide performances in various scenarios. We build the “carbon emission elasticity of profit (CEEP)” index as a metric to evaluate the impact of regulatory policies on both chainwide emissions and profit. Our results manifest that by facilitating the mandatory emission cap in proper installation within the network one can balance well effective emission reduction and associated acceptable profit loss. The outcome that CEEP index when implementing Carbon emission tax is elastic implies that the scale of profit loss is greater than that of emission reduction, which shows that this policy is less effective than mandatory cap from industry standpoint at least. Longfei He, Zhaoguang Xu, and Zhanwen Niu Copyright © 2014 Longfei He et al. All rights reserved. Game Theoretic Analysis of Carbon Emission Reduction and Sales Promotion in Dyadic Supply Chain in Presence of Consumers’ Low-Carbon Awareness Tue, 15 Jul 2014 07:24:26 +0000 http://www.hindawi.com/journals/ddns/2014/837376/ The paper studies how the combination of the manufacturer’s carbon emission reduction and the retailer’s emission reduction relevant promotion impacts the performances of a dyadic supply chain in low-carbon environment. We consider three typical scenarios, that is, centralized and decentralized without or with side-payment. We compare measures of supply chain performances, such as profitabilities, emission reduction efficiencies, and effectiveness, in these scenarios. To improve chain-wide performances, a new side-payment contract is designed to coordinate the supply chain and numerical experiments are also conducted. We find the following. (1) In decentralized setting, the retailer will provide emission cutting allowance to the manufacturer only if their unit product profit margin is higher enough than the manufacturer’s, and the emission reduction level of per unit product is a monotonically increasing function with respect to the cost pooling proportion provided by the retailer; (2) the new side-payment contract can coordinate the dyadic supply chain successfully due to its integrating sales promotion effort and emission reduction input, which results in system pareto optimality under decentralized individual rationality but achieves a collective rationality effect in the centralized setting; (3) when without external force’s regulation, consumers’ low-carbon awareness is to enhance consumers’ utility and decrease profits of supply chain firms. Liangjie Xia and Longfei He Copyright © 2014 Liangjie Xia and Longfei He. All rights reserved. Dynamics of Third-Order Nonlinear Neutral Equations Mon, 14 Jul 2014 11:22:01 +0000 http://www.hindawi.com/journals/ddns/2014/917913/ The aim of this paper is to study oscillatory and asymptotic properties of the third-order nonlinear neutral equation with continuously distributed delays of the form . Applying suitable generalized Riccati transformation and integral averaging technique, we present new criteria for oscillation or certain asymptotic behavior of nonoscillatory solutions of this equation. Obtained results essentially improve and complement earlier ones. Hua Wang, Li Liu, and Yanxiang Tan Copyright © 2014 Hua Wang et al. All rights reserved. Stability of Nonlinear Fractional Neutral Differential Difference Systems Mon, 14 Jul 2014 10:03:04 +0000 http://www.hindawi.com/journals/ddns/2014/514631/ We study the stability of a class of nonlinear fractional neutral differential difference systems equipped with the Caputo derivative. We extend Lyapunov-Krasovskii theorem for the nonlinear fractional neutral systems. Conditions of stability and instability are obtained for the nonlinear fractional neutral systems. Kewei Liu and Wei Jiang Copyright © 2014 Kewei Liu and Wei Jiang. All rights reserved. Dynamic Prediction of Financial Distress Based on Kalman Filtering Thu, 10 Jul 2014 10:29:29 +0000 http://www.hindawi.com/journals/ddns/2014/370280/ The widely used discriminant models currently for financial distress prediction have deficiencies in dynamics. Based on the dynamic nature of corporate financial distress, dynamic prediction models consisting of a process model and a discriminant model, which are used to describe the dynamic process and discriminant rules of financial distress, respectively, is established. The operation of the dynamic prediction is achieved by Kalman filtering algorithm. And a general -step-ahead prediction algorithm based on Kalman filtering is deduced in order for prospective prediction. An empirical study for China’s manufacturing industry has been conducted and the results have proved the accuracy and advance of predicting financial distress in such case. Qian Zhuang and Lianghua Chen Copyright © 2014 Qian Zhuang and Lianghua Chen. All rights reserved. Periodic Solutions of Second Order Nonlinear Difference Equations with Singular -Laplacian Operator Thu, 10 Jul 2014 09:53:25 +0000 http://www.hindawi.com/journals/ddns/2014/637242/ We obtain some existence results of solutions for discrete periodic boundary value problems with singular -Laplacian operator , , , and by using the upper and lower solutions method and Brouwer degree theory, where is a constant, , , , and is a parameter. We also give some examples with singular nonlinearities to illustrate our main results. Ruyun Ma and Yanqiong Lu Copyright © 2014 Ruyun Ma and Yanqiong Lu. All rights reserved. Forecasting Return Volatility of the CSI 300 Index Using the Stochastic Volatility Model with Continuous Volatility and Jumps Wed, 09 Jul 2014 08:01:38 +0000 http://www.hindawi.com/journals/ddns/2014/964654/ The logarithmic realized volatility is divided into the logarithmic continuous sample path variation and the logarithmic discontinuous jump variation on the basis of the SV-RV model in this paper, which constructs the stochastic volatility model with continuous volatility (SV-CJ model). Then, we use high-frequency transaction data for five minutes of the CSI 300 stock index as the study sample, which, respectively, make parameter estimation on the SV, SV-RV, and SV-CJ model. We also comparatively analyze these three models' prediction accuracy by using the loss functions and SPA test. The results indicate that the prior logarithmic realized volatility and the logarithmic continuous sample path variation can be used to predict the future return volatility in China's stock market, while the logarithmic discontinuous jump variation is poor at its prediction accuracy. Besides, the SV-CJ model has an obvious advantage over the SV and SV-RV model as to the prediction accuracy of the return volatility, and it is more suitable for the research concerning the problems of financial practice such as the financial risk management. Xu Gong, Zhifang He, Pu Li, and Ning Zhu Copyright © 2014 Xu Gong et al. All rights reserved. Using Improved Ant Colony Algorithm to Investigate EMU Circulation Scheduling Problem Mon, 07 Jul 2014 12:41:57 +0000 http://www.hindawi.com/journals/ddns/2014/767429/ High-speed railway is one of the most important ways to solve the long-standing travel difficulty problem in China. However, due to the high acquisition and maintenance cost, it is impossible for decision-making departments to purchase enough EMUs to satisfy the explosive travel demand. Therefore, there is an urgent need to study how to utilize EMU more efficiently and reduce costs in the case of completing a given task in train diagram. In this paper, an EMU circulation scheduling model is built based on train diagram constraints, maintenance constraints, and so forth; in the model solving process, an improved ACA algorithm has been designed. A case study is conducted to verify the feasibility of the model. Moreover, contrast tests have been carried out to compare the efficiency between the improved ACA and the traditional approaches. The results reveal that improved ACA method can solve the model with less time and the quality of each representative index is much better, which means that efficiency of the improved ACA method is higher and better scheduling scheme can be obtained. Yu Zhou, Leishan Zhou, and Yun Wang Copyright © 2014 Yu Zhou et al. All rights reserved. Motivation Mechanism Prevents Adverse Selection in Industrial Technology Innovation Strategic Alliance Mon, 07 Jul 2014 07:09:46 +0000 http://www.hindawi.com/journals/ddns/2014/463956/ Choosing proper partners is the key to the success of the alliance. Based on the analysis of the characters of the Industrial Technology Innovation Strategic Alliance, a new kind of cooperative organization occurred in China in recent years. The problem of “adverse selection” at the stage of the its establishment is discussed in this paper. The game model is built based on motivation theory and the principle-agent theory and then proved by examples. The conclusions can be got from the model. By setting the ranges of funds, preferential policy, and sharable profits and designing membership rules, the organizer of the Industrial Technology Innovation Strategic Alliance can motivate the risk neutral applicant to reveal his real capacity and the one with higher capacity to participate intothe alliance more actively and even can set capacity threshold for applicants implicitly. Mingxia Zhao and Changhong Li Copyright © 2014 Mingxia Zhao and Changhong Li. All rights reserved. Multiobjective Network Optimization for Soil Monitoring of the Loess Hilly Region in China Sun, 06 Jul 2014 11:32:55 +0000 http://www.hindawi.com/journals/ddns/2014/805175/ The soil monitoring network plays an important role in detecting the spatial distribution of soil attributes and facilitates sustainable land-use decision making. Reduced costs, higher speed, greater scope, and a loss of accuracy are necessary to design a regional monitoring network effectively. In this paper, we present a stochastic optimization design method for regional soil carbon and water content monitoring networks with a minimum sample size based on a modified particle swarm optimization algorithm equipped with multiobjective optimization technique. Our effort is to reconcile the conflicts between various objectives, that is, kriging variance, survey budget, spatial accessibility, spatial interval, and the amount of monitoring sites. We applied the method to optimize the soil monitoring networks in a semiarid loess hilly area located in northwest China. The results reveal that the proposed method is both effective and robust and outperforms the standard binary particle swarm optimization and spatial simulated annealing algorithm. Dianfeng Liu, Yaolin Liu, Mingze Wang, and Xiang Zhao Copyright © 2014 Dianfeng Liu et al. All rights reserved. Optimal Control of a Make-to-Stock System with Outsourced Production and Price-Sensitive Demand Sun, 06 Jul 2014 09:22:53 +0000 http://www.hindawi.com/journals/ddns/2014/301309/ We consider a make-to-stock system with controllable demand rate (by varying product selling price) and adjustable service rate (by outsourcing production). With one outsourcing alternative and a choice of either high or low price, the system decides at any point in time whether to produce or even outsource for additional capacity as well as which price to sell the product at. We show in the paper that the optimal control policy is of dynamic threshold type: all decisions are based on the product inventory position which represents the state of the system; there is a state dependent base stock level to decide on production and a higher level on outsourcing; and there is a state dependent threshold which divides the choice of high and low prices. Liuxin Chen, Gang Hao, and Huimin Wang Copyright © 2014 Liuxin Chen et al. All rights reserved. Agent-Based Modeling and Simulation for the Bus-Corridor Problem in a Many-to-One Mass Transit System Sun, 06 Jul 2014 07:32:57 +0000 http://www.hindawi.com/journals/ddns/2014/652869/ With the growing problem of urban traffic congestion, departure time choice is becoming a more important factor to commuters. By using multiagent modeling and the Bush-Mosteller reinforcement learning model, we simulated the day-to-day evolution of commuters’ departure time choice on a many-to-one mass transit system during the morning peak period. To start with, we verified the model by comparison with traditional analytical methods. Then the formation process of departure time equilibrium is investigated additionally. Seeing the validity of the model, some initial assumptions were relaxed and two groups of experiments were carried out considering commuters’ heterogeneity and memory limitations. The results showed that heterogeneous commuters’ departure time distribution is broader and has a lower peak at equilibrium and different people behave in different pattern. When each commuter has a limited memory, some fluctuations exist in the evolutionary dynamics of the system, and hence an ideal equilibrium can hardly be reached. This research is helpful in acquiring a better understanding of commuter’s departure time choice and commuting equilibrium of the peak period; the approach also provides an effective way to explore the formation and evolution of complicated traffic phenomena. Qinmu Xie, Shoufeng Ma, Ning Jia, and Yang Gao Copyright © 2014 Qinmu Xie et al. All rights reserved. Incorporating Overconfidence into Real Option Decision-Making Model of Metal Mineral Resources Mining Project Thu, 03 Jul 2014 10:10:43 +0000 http://www.hindawi.com/journals/ddns/2014/232516/ As for uncertainties and decision-makers’ overconfidence psychological bias, overconfidence has been incorporated into real option decision-making model of metal mineral resources mining to estimate its effect on decision-making of the project and thus a behavioral real option decision-making model of metal mineral resources mining based on overconfidence has been established. Furthermore, numerical simulation and sensitivity analysis have been conducted to verify the practicality of the model. Results show that model in this paper has greatly changed trigger value and option value of mineral resources mining project compared with traditional real option model, thus greatly changing optimal decision results. Incorporating overconfidence into real option decision-making model of metal mineral resources development is a crucial extension of project evaluation theory. Jian-bai Huang, Na Tan, and Mei-rui Zhong Copyright © 2014 Jian-bai Huang et al. All rights reserved. Group Consensus with a Dynamic Leader for Multiagent Systems via Sampled-Data Control Thu, 03 Jul 2014 09:50:05 +0000 http://www.hindawi.com/journals/ddns/2014/129410/ This paper considers a group consensus problem with a dynamic leader for multiagent systems in a sampled-data setting. With the leader’s state available to only a fraction of the followers, a distributed linear protocol based on sampled-data control is proposed for group consensus under fixed directed topology. On basis of -matrix theory, we derive a sufficient condition on the sampling period and the control parameter for ultimate boundedness of the tracking errors. Furthermore, simulation examples are provided to demonstrate the effectiveness of the theoretical results. Hong Xia, Ting-Zhu Huang, Jin-Liang Shao, and Jun-Yan Yu Copyright © 2014 Hong Xia et al. All rights reserved. Options Procurement Policy for Option Contracts with Supply and Spot Market Uncertainty Tue, 01 Jul 2014 12:05:31 +0000 http://www.hindawi.com/journals/ddns/2014/906739/ Supplier’s reliability is a major issue in procurement management. In this paper, we establish a decision making model from the perspective of the firm who will procure from the multiple suppliers and the spot markets. The suppliers are unreliable and provide different types of option-type supply contracts which should be made before demand realization, while the spot market can only be used after demand realization and has both the price and liquidity risks. We establish the optimal portfolio policies for the firm with conditions to find the qualified suppliers. By defining a new function which contains the demand risk, the supplier’s risk, and the liquidity risk, we find that the optimal policy is to allocate different curves of this function to different suppliers. We also study some special cases to derive some managerial insights. At last, we numerically study how the various risks affect the choice of suppliers and the value of the option contract. Weili Xue, Xiaolin Xu, and Lijun Ma Copyright © 2014 Weili Xue et al. All rights reserved. Partitioning Technique for Relaxed Stability Criteria of Discrete-Time Systems with Interval Time-Varying Delay Mon, 30 Jun 2014 11:14:53 +0000 http://www.hindawi.com/journals/ddns/2014/297324/ We demonstrate an improved stability analysis based on a partition oriented technique for discrete-time systems with interval time-varying delay. The partition oriented technique introduces beneficial terms contributing to the negative definiteness of the Lyapunov function difference, meanwhile completely avoiding traditional inequality based approaches. In contrast, nonpartitioning oriented techniques do not put emphasis on further dividing the interval of the summation in the Lyapunov function. Herein, we demonstrate that the advantages of exploiting partitioning techniques manifest the relaxed stability criteria, as well as the flexibility to tune tradeoff between allowable timedelay range performance and computational load. Simulation carried out on a benchmark discrete-time system reveals the significant improvement in terms of maximum allowable upper bound in comparison. Kuang-Yow Lian, Wen-Tsung Yang, and Peter Liu Copyright © 2014 Kuang-Yow Lian et al. All rights reserved. Cluster Synchronization of Stochastic Complex Networks with Markovian Switching and Time-Varying Delay via Impulsive Pinning Control Thu, 26 Jun 2014 06:50:25 +0000 http://www.hindawi.com/journals/ddns/2014/835867/ This paper studies the cluster synchronization of a kind of complex networks by means of impulsive pinning control scheme. These networks are subject to stochastic noise perturbations and Markovian switching, as well as internal and outer time-varying delays. Using the Lyapunov-Krasovskii functional, Itö’s formula, and some linear matrix inequalities (LMI), several novel sufficient conditions are obtained to guarantee the desired cluster synchronization. At the end of this writing, a numerical simulation is given to demonstrate the effectiveness of those theoretical results. Xuan Zhou and Kui Luo Copyright © 2014 Xuan Zhou and Kui Luo. All rights reserved. Optimal Time-Consistent Investment Strategy for a DC Pension Plan with the Return of Premiums Clauses and Annuity Contracts Tue, 24 Jun 2014 12:53:36 +0000 http://www.hindawi.com/journals/ddns/2014/862694/ Defined contribution and annuity contract are merged into one pension plan to study both accumulation phase and distribution phase, which results in such effects that both phases before and after retirement being “defined”. Under the Heston’s stochastic volatility model, this paper focuses on mean-variance insurers with the return of premiums clauses to study the optimal time-consistent investment strategy for the DC pension merged with an annuity contract. Both accumulation phase before retirement and distribution phase after retirement are studied. In the time-consistent framework, the extended Hamilton-Jacobi-Bellman equations associated with the optimization problem are established. Applying stochastic optimal control technique, the time-consistent explicit solutions of the optimal strategies and the efficient frontiers are obtained. In addition, numerical analysis illustrates our results and also deepens our knowledge or understanding of the research results. De-Lei Sheng and Ximin Rong Copyright © 2014 De-Lei Sheng and Ximin Rong. All rights reserved.