Table of Content

30 August 2013, Volume 21 Issue 4 Previous Issue    Next Issue

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Financial Risk Measurement Based on Asymmetric Laplace Distribution DU Hong-jun, WANG Zong-jun 2013, 21 (4):  1-7.  Abstract ( 3040 )   PDF (1275KB) ( 2343 )   Save The actual distribution of asset returns possesses the characters of steep peaks, heavy tails and asymmetry, in this paper, asymmetric laplace distribution is used to fit the data of asset returns and described these features. Then, AL parametric method and AL-MC method are employed to measure VaR and CVaR. The Shanghai Composite Index, Nikkei225 Stock Index and S&P500 Index are selected in the calculation of VaR and CVaR considering actual stocks risk features. Also, the back testing and accuracy assessment of risk are given. The results show that the risk measurement model based on Asymmetric Laplace distribution is reasonable and applicable and can effectively estimated the market risk. References | Related Articles | Metrics

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A Decision Model for Multi-market Advertising Budget Allocation Based on Vidale-Wolfe Model ZHANG Peng, WANG Xing-yuan 2013, 21 (4):  8-16.  Abstract ( 3082 )   PDF (1388KB) ( 2233 )   Save Advertising decision problem has been a hotspot concerned by marketing managers and scholars for a long time. More and more enterprises are facing multi-market with the development of society and economy and it becomes a more important problem for enterprises that how to allocate advertising budget to get the best advertising effect in condition of multi-market and fixed total advertising budget. Vidale-Wolfe model is selected as the advertising response model, based on which the decision model for multi-market advertising budget allocation is proposed. As some marketing strategy requires special sales rate demands in some markets. The proposed model consists of two parts: the latter cares about how to keep certain sales rate, while the former does not. The optimization model is constructed. The method to get arguments value and how to solve the model are discussed. An example is given at last. References | Related Articles | Metrics

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Tail Conditional Variance of Portfolio with Mixture of Elliptically Distributions JIANG Chun-fu, YANG Yu-kuan 2013, 21 (4):  17-26.  Abstract ( 2514 )   PDF (1696KB) ( 2134 )   Save Since downside risk measures such as VaR and CVaR have flaws in characterizing the variance of tail data and measuring extreme financial risk, the tail conditional variance, the variance of loss beyond VaR, motivated by tail conditional expectation is studied in this paper. The explicit solution of the tail conditional variance of portfolio under a mixture of multivariate elliptically distributions and an important heavy tail distribution in modeling financial data are obtained. Some numerical examples and empirical application on the optimal portfolio selection are finally provided to illustrate the proposed method. The results can help investors to better control extreme portfolio risk. References | Related Articles | Metrics

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The Optimization and Decision-making of Principal-agent Problem Based on Time-inconsistency Preference ZOU Zi-ran, CHEN Shou, YANG Yan, ZHANG Hong-hao 2013, 21 (4):  27-34.  Abstract ( 2719 )   PDF (1384KB) ( 2008 )   Save When discounting returns and costs at different points about the principal-agent problem are involved, nearly all existing studies choose exponential discounting function, which is the only discounting function standing for time-consistency. This paper relaxes the time-consistency preference hypothesis, taking quasi-hyperbolic discounting-βδ as the agents' discounting function. How principals inspire agents to work hard is considered in order to maximize their profits when principals' costs and returns occur at different points and returns are determined by the level of efforts and external factors. The findings suggest that the optimal contract is related with the present-biased parameters β and the beliefs about the future present-biased parameter . Principals obtain more expected profits from time-consistency preference agents than time-inconsistency preference agents and obtain more expected profits from sophisticated agent than partially naive and pessimistic agent. However, they obtain equal expected profits from sophisticated agent and partially naive and optimistic agent. References | Related Articles | Metrics

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Dual Sourcing Decisions under Exchange Rate and Supply Risks WEN Yuan, XIAO Yong-bo 2013, 21 (4):  35-43.  Abstract ( 2817 )   PDF (1037KB) ( 2047 )   Save Dual sourcing is an effective way for procurement risk diversification. This paper considers a risk-averse manufacturer that faces two sourcing alternatives: a domestic supplier that is unreliable, and a supplier in the manufacturer's home country that is fully reliable, and actual price of components is affected by fluctuated exchange rate. The joint optimal procurement decision for the risk-averse manufacturer is developed and is compared with the situation of risk neutrality. Modeling analysis shows that the risk-neutral manufacturer only places order to single supplier. The risk-averse manufacturer, however, is influenced by the fluctuations of both exchange rate and supply and their correlation. When the reliability and exchange rate correlates, it may procure from both sources so as to reduce risk. Results from numerical study show that dual sourcing can lower the loss risk. References | Related Articles | Metrics

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On-time Delivery Model In a ‘N to 1’ Assembly System with Inventory Sharing Policy GUAN Xu, MA Shi-hua, YING Dan-feng 2013, 21 (4):  44-52.  Abstract ( 2252 )   PDF (1034KB) ( 2051 )   Save In a assembly system with uncertain demand time, suppliers' uncoordinated deliver times can heavily bring down the manufacturer's and the supply chain's performances. Under such a circumstance, manufacturer has to use some inventory control policies (e.g., VMI) to reduce his inventory cost, while the supplier tries to deliver at the most appropriate time. In this paper, the supplier optimal deliver time and the manufacturer's best inventory holding period in an assemble system with uncertain demand time are studied. To this end, two different models are conducted in N-1 setting: the Nash game among the multi-suppliers, and the Stacklberg game between the manufacturer and the suppliers. The manufacturer's optimal limited inventory holding period under two different conditions is also discussed. One is the manufacturer that sets the same inventory holding period to all the suppliers, and the other is the manufacturer that can choose different inventory holding periods to the different suppliers. The result identifies the suppliers' optimal deliver time and shows that the manufacturer can effectively improve his and the channel's profit by either means. In other words, traditional VMI policy isn't good for neither the manufacturer nor the supply chain. By numerical analysis, the sensitivities of the supplier heterogeneity are identified, and it is shown that the supply chain efficiency increases when the manufacturer is able to choose different inventory holding periods. Moreover, the essential condition for the supply chain coordination is concisely provided. References | Related Articles | Metrics

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Percolation’s Criticality of Moral Hazards in Supply Chain XU Xu-song, ZHENG Xiao-jing, ZHENG Zhan 2013, 21 (4):  53-61.  Abstract ( 2366 )   PDF (1508KB) ( 2064 )   Save To quantify the critical point of controlling moral hazard keeping supply chain from operating normal, a complex networks model of moral hazards in supply chain, with perspective of people in this system, is constructed, and the properties of inducing and transferring moral hazards in supply chain and the law of topological evolution of supply chain moral hazards system are given. By invoking percolation theory and the corresponding methods coupling with the property of transferring character of moral hazards in supply chain, control moral hazards and their transferring process according to random attack and intention attack, respectively, and the minimization number of the employees should be controlled, so as to give the percolation criticality of moral hazards in supply chain. It is concluded that random attack makes moral hazards robustness but intention attack make them vulnerability, Furthermore, the intention attack to moral hazards in supply chain is effective, and the probability of controlling moral hazards of intention attack in supply chain is decided by the configuration of supply chain with perspective of staffs and the property of moral hazards. References | Related Articles | Metrics

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Research of Purchasing Strategy Coordination on Reliefsupply Chain WANG Xi-hui, LIANG Liang 2013, 21 (4):  62-73.  Abstract ( 2223 )   PDF (1304KB) ( 2190 )   Save In relief material management, the purchaser is wrestling with a dilemma in purchase strategy. Reactive purchasing from supermarket implies zero inventory cost but the unit price is high. Proactive purchasing from manufactory is in risk of loss but the unit price is low. By introducing the methodology on supply chain management into relief material management, the supply chain system of a single-purchaser and single-supplier is considered. The research gives out the condition under which, compared with purchasing from supermarket with return policy, proactive purchasing relief material from manufactory with option contract can coordinate the relief material supply chain and achieve Pareto-improvement as well. Moreover, by considering the risk level and risk performance, the profit distribution with an option contract which is acceptable for both the supplier and the purchaser is proposed. References | Related Articles | Metrics

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Empirical Research on Price Impact Factors of Carbon Exchange of Voluntary Market：Evidence from CCX of USA CHEN Xiao-hong, HU Wei, WANG Zhi-yun 2013, 21 (4):  74-81.  Abstract ( 2777 )   PDF (873KB) ( 2784 )   Save China's twelfth five-year plan proposes that the establishment of volunteer emission reduction (VER) carbon market and good trading mechanism is required to underlie sustainable development of the market. This paper focuses on the influential factors of exchange price to discover price formation which is the core issue of exchange mechanism. First, theoretical analysis from three aspects including supply, demand and market effect is conducted. Then, the samples of carbon securities' exchange price (2003-2010) in the Chicago Climate Exchange (CCX) are used to check impact factors by AR(1)-GARCH (1,1) model with panel regression. The research result shows that the primary impact factor of pricing in phaseⅠis quota supply and demand, and there is an upward tendency in the effect degree of different products. In phase Ⅱenergy price has a great effect and gas price becomes a significant factor. The result offers a good reference to the construction of voluntary carbon market in China. References | Related Articles | Metrics

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Supply Chain Coordination Strategy Considering Dual Competition from Price and Quality XIAO Di, YUAN Jing-xia, BAO Xing 2013, 21 (4):  82-88.  Abstract ( 2352 )   PDF (1413KB) ( 2422 )   Save Under the new circumstance with intense competition, the enterprise should balance the relationship between the price and the quality, coordinating its chain members' decision-making to develop the optimally competitive strategy with the full consideration of the behavior of competitors. And it will not meet the need of operational decision making if only the price or the quality are considered. The article examines such questions in a dynamic game of a supply chain system consisting two suppliers and a manufacturer. And it analyzes the equilibriums in four different scenarios, namely, chain cooperating, supplier cooperating, supplier non-cooperating and mixed cooperating; and the impact of price and quality competition exertang on final decision-making such as retail price, quality effort and profit is discussed. The results show that cooperation of suppliers can contribute to quality improvement but it may lead to profit reduction of the whole chain. In most situations, the more intense the quality competition is, the more effort the suppliers make, especially in the cooperative situation. However, the influence of price competition on supplier's quality effort is bounded or even can be ignored. References | Related Articles | Metrics

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A Decision Model for Promotion Time in Multi-products Price Promotion Based on the Profit of Retailers LI Ji, ZHOU Li-chao, WANG Han-sheng 2013, 21 (4):  89-97.  Abstract ( 1936 )   PDF (972KB) ( 1518 )   Save In the mounting competition of the retailing business, price promotion is one of the frequently used strategies and becomes the major part of retailers' marketing budget. Previous researches on price promotion often focus on particular brands or products from manufacturers' perspect. Few are conducted for retailers. To fill the gap in price promotion literature, the present study developed this multi-products promotion model to evaluate the the effects of price promotion on the profit of retailers by simultaneously taking multiple products and their promotion time into consideration. The multi-products promotion model is as followed: where Yi is the retailer's profit in day i, Xi=(Xi1,Xi,…,Xip) and Xij is the promotion degree of j th product in day i, p is the total number of products. Tij is the total promotion days of j th product from the beginning to day i, P1j,P2j,P3j are catagory characteristics varibles, D1j,D2j are product specific varibles,Wi is a dummy variable to denote whether day i is weekend. ω0, ω, γ0, γ1, γ2, γ3, γ4, γ5, γ6, γ7 are the parameters to be estimated. This paper used the daily sales records in 159 days from a large chain supermarket for emprical analysis. The data included the name, id number, price, daily sales volume and promotion price of products which are sold by the surpermarket. Preliminary calculation were conducted to quantify the products characteristics, category characteristics and promation time. By introducing these characteristics variables, we could examine the effects that price promotion of individual product has on the retailer's profit.Results shows that price promotion of individual product can significantly affect the total profit of the retailer. Moreover, the effect of price promotion is segnificantly related to promotion time and whether in weekend or not. As time goes on, the promotion effect decreases and even becomes negtive on retailer's profit. The promotion effect is better in weekend than in weekdays. So determing the proper promotion time for promoting products is critical for retailers. This study extended the previous promotion research by emphasizing on retailers and developing an empirical model to examine the role of individual product's promotion on retailers profit. By employing this model, retailers can develop more scientific and feasible price promotion strategies for individual product. In particular, retailers can dynamically monitor the impact of every product in promotion on the profit of the entire store and accordingly adjust promotion time to maximize their profit. References | Related Articles | Metrics

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Supply Chain Coordination under Market Demand and Production Costs Disruptions by Adjusting Option Contracts WU Zhong-he, CHEN Hong, ZHAO Qian 2013, 21 (4):  98-104.  Abstract ( 2118 )   PDF (866KB) ( 2347 )   Save In recent years, emergency events such as nature disaster, terror attack etc. occur frequently, which affect the normal operation of enterprises and supply chain tremendously. Thus, this question leads to a wide attention about how to coordinate the supply chain to response to disruptions. On the other hand, the option contracts have a wide application in the supply chain coordination because of their good flexibility, but in previous studies,only few of them use the option contract to coordinate the supply chain to response to disruptions and verify its validity, and this is just the field that will be explored in this paper. In this paper, we considering a two-stage supply chain composed of one manufacturer and one retailer, while the disruptions cause the stochastic market demand distribution function and the manufacturer's production cost fluctuated simultaneously, how to coordinate the supply chain to response to the disruption by using the option contract is discussed in this paper. A supply chain coordination model is set up based on option contract firstly. As the disruption may affect the supply chain production plan and furthermore it will cause the manufacturer to adjust the production quantity, the production quantity adjustment need to throw in deviation cost. So in the emergency environment, a supply chain model iset up based on a option contract by drawing (leading) into deviation cost. In addition, the model is analyzed thoroughly. As for the thinking of the question resolvent, firstly the coordination mechanism with the option contract of supply chain in steady environment is studied in this paper. Then, the option contract coordination strategy is researched in the light of the supply chain in the emergency environment. The results show that the supply chain can be coordinated by adjusting the order quantity when stochastic market demand distribution function and production cost fluctuated simultaneously. Furthermore, it is found that only the adjusted option contract can coordinate the supply chain while the origin option contract can't. Thereby it is verified that it is effective and essential to coordinate the supply chain by adjusting the option contract while disruptions occur. Finally, the model in this paper is verified by numerical experiments. In the part of data emulation and analysis, a living example is designed according to the feature of the short life cycle two-stage supply chain. Furthermore, the numeral example combining with four conditions produced is analyzed by stochastic market demand distribution function and production cost fluctuation simultaneously. The numeral example shows that the supply chain emergency coordination model is correct. In brief, this study offers a fundamental train of thought and a frame for coordinating the supply chain to response to disruptions to the other related studies. Moreover, it can be used as reference to the other related studies about how to lead the option contract into coordinating the supply chain to response to disruptions. References | Related Articles | Metrics

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The Study of Multi-stage Supply Chain Cost Distribution Based on GERT Model LI Chong, LIU Si-feng, FANG Zhi-geng, BAI Yang 2013, 21 (4):  105-111.  Abstract ( 2190 )   PDF (1744KB) ( 2057 )   Save Supply chain cost management is an important part in enterprise strategic management. The components and distribution problem of cost in multi-stage supply chain networks is studied in this paper. Based on the graphical evaluation and review technique, a novel stochastic network mathematical model for cost analysis in multi-stage supply chain networks is built. Model structure characteristics and parsing algorithm are provided firstly. Further, to study the effects of cost components (production cost, inventory cost and transportation cost) and cost fluctuations of supply chain members on total cost, we provide algorithms based on the proposed cost analysis model is provided. Finally the effectiveness and flexibility of proposed model and algorithms are verified by simulation study. References | Related Articles | Metrics

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Multi-attribute Bidding Mechanism Design for Warranted Lifetime Products：A case study on Large Medical Equipments MA Ben-jiang, XU Bi-wu, XU Chen 2013, 21 (4):  112-120.  Abstract ( 2402 )   PDF (901KB) ( 2026 )   Save For the life expectancy of single major medical equipment cannot be observed or verified and it is one of the key quality indicators,it has no meaning to directly bid for this quality attribute. To this problem, warranty is introduced into bidding mechanism of hospital procurement as an important decision variable, and a new multi-attribute bidding model with signal transduction function is established based on the auction mechanism design theory. The optimal bidding rules, including best bid for equipment life expectancy,best bid for equipment warranty, and the best price to pay is defined in the model. A mechanism that could identify enterprises' technology types and transmit information about product quality reliability is also established. The results show that: firstly, this mechanism satisfied participation constraint and incentive compatibility constraint.In other words, bidding enterprises can bid for the maximal profits separately according to their own expectations;Secondly, this optimal mechanism ensures a positive correlation between life expectancy and warranty that enterprises committed. It also ensures enterprises, which are the highest technical types and provide maximum product life expectancy (warranty period the longest), win the bidding. It also ensure the successful company create a relatively highest social welfare. A example is used to illustrate the new mechanism which is enforceable and easy to operate. A new idea when the quality dimension can not be observed and verified is provided by the research. References | Related Articles | Metrics

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Imbalance of Economy after Disaster Based on Input-output Model and Path Recovery ZHU Jing 2013, 21 (4):  121-128.  Abstract ( 2424 )   PDF (1028KB) ( 2002 )   Save The existing input-output model can't adequately describe the imbalance of economy after disaster. Introducing the labor market(L=lx)into the open IO model(x=Ax+f)and reestablishing the closed model(x=M·x), it can better describe the imbalance of economic circular flow by the relationship of labor, final demand and total output after the disaster, and set the beginning of reconstruction. Based on the work of predecessors, the calculation method of F matrix in the closed IO model is improved in this paper; the imbalance of economy after the disaster is simulated by introducing the loss coefficient, and the possible recovery paths is searched by the scenario analysis. Then the output loss of Wenchuan Earthquake in 2008 is computed by the IO table of Sichuan in 2007, and the validity of this model is verified by simulating the possible recovery paths. The results shows that this model can help government to find recovery "bottleneck" promptly after the disaster and make scientific decision of reconstruction. References | Related Articles | Metrics

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Signaling Game Model of Government and Enterprise Based on the Subsidy Policy for Energy Saving and Emission Reduction ZHANG Guo-xing, ZHANG Xu-tao, CHENG Su-jie, CHAI Guo-rong, WANG Long-long 2013, 21 (4):  129-136.  Abstract ( 2505 )   PDF (1106KB) ( 3209 )   Save Subsidy policy for energy saving and emission reduction has been widely used in our country, but the high-cost expenditures promote the existence of gaming between enterprise and the government in the process of advancing energy saving and emission reduction. Considering the subsidy policy for energy saving and emission reduction, a signaling game model of enterprise and government on subsidies is constructed in this paper. Owing to information asymmetry and imperfection, three kinds of equilibrium including complete success, partial success and complete failure come to existence, and efficiency of market equilibrium will be influenced by the disguised cost and expected risk cost, therefore, the key to achieve completely successful balance is to improve the camouflage cost of enterprise fraud and the expected cost of risk, and thus appropriate policies should be focused on fields such as refining policies &standards, increasing the efficiency of checks and setting penalties in large. By a simple analysis of collusion between government and enterprises it suggests that building a more comprehensive and multi-dimensional assessment indicators, giving play to inquiry and supervision raised by third parties such as the public and media can constrain the collusion between government and enterprises effectively. References | Related Articles | Metrics

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Study on Dynamic Tag Correlation Web for Open Team Knowledge Innovation LI Xin-miao, LI Jia, XIE Hang, XIE Hong-yu 2013, 21 (4):  137-143.  Abstract ( 1974 )   PDF (1226KB) ( 1718 )   Save Knowledge innovation is the key to improve core competence of enterprises. The global innovation trends have been shrugging off the physical constraints in the context of globalization. In the open environment, cross-organization and cross-region open innovation teams become the main functional bodies for knowledge innovation. Social tagging enables knowledge transition and cooperation between team members according to their own wills and encourages knowledge innovation for open teams. However, due to the freedom of tagging, how to build tag correlation so as to effectively support knowledge management and knowledge innovation in open environment is the critical issue that needs to be solved. In this paper, dynamic tag correlation web for open team knowledge innovation is proposed and studied. This method is applied to case study afterwards. By comparison of results from experimental group and control group, differentiation between strong tag correlation and weak tag correlation can be distinguished. In addition, timeliness with popular tags is explored the tag correlation web. It can be seen that the dynamic tag correlation web for open team knowledge innovation can represent the tag correlation dynamically and support knowledge innovation in open environment. References | Related Articles | Metrics

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The Influence of Check-and-balance Ownership Structure on the M&A Performance under Idiosyncratic Expectations LIU Xin, JIANG Hong 2013, 21 (4):  144-151.  Abstract ( 2341 )   PDF (1364KB) ( 1770 )   Save By a way of theory model establishment, the influence of check-and balance ownership structure on the M&A performance under idiosyncratic expectations is investigated in this paper. The results show that investors' idiosyncratic expectations will lead to the declining adjustment of acquirer's stock price after M&A transaction, and then result in the drop of M&A performance, which is measured by stock price. Under appropriate idiosyncratic expectations, the check-and-balance ownership structure will reduce the extent of M&A performance drop. The higher the check-and-balance degree is, the better the M&A performance will be. However, along with the strengthen of idiosyncratic expectations, the influence of check-and balance ownership structure on the M&A performance will become nonlinear when idiosyncratic expectations go beyond the appropriate range. References | Related Articles | Metrics

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Ownership Concentration, Investment Policy and Agency Costs SONG Xiao-bao 2013, 21 (4):  152-161.  Abstract ( 2529 )   PDF (2181KB) ( 2702 )   Save In this paper, by building the real options model, the impact of controlling shareholder agency over the investment policy, corporate value and agency costs under the ownership concentration is esamined.The research shows that the controlling shareholders-maximizing motivation will lead to over-investment, which cause higher agency costs of debt. The entrenchment of controlling shareholders not only affects the agency conflicts of different shareholders, but also the agency conflicts of stockholder and bondholder. Increasing of ownership of controlling shareholder can lighten the overinvestment, increase corporate value and decrease the agency costs of debt, which shows the incentive effect of corporate governance. Increasing of the separation degree of control from cash flow of controlling shareholder can aggravate overinvestment, decrease corporate value and increase the agency costs of debt, which shows the entrenchment effects of corporate governance. References | Related Articles | Metrics

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The Relationship Between Corporate Social Responsibility Disclosure and Corporate Financial Performance under Media Exposure and its Implications：An Empirical Study Based on the CSR Report of Chinese Listed Firms TAO Wen-jie, JIN Zhan-ming 2013, 21 (4):  162-170.  Abstract ( 3326 )   PDF (877KB) ( 2222 )   Save Nowadays,corporate social responsibility(CSR)and relative infromation disclosure have been hot spots of the public.Using the data on the ranking of Chinese listed firm's CSR reports, which is obtained from an independent institution, the relationship between corporate social responsibility disclosure(CSRD) and corporate financial performance(CFP), and the role played by media exposure, which acts as information distribution medium and the director of "public agenda setting" in the relationship between CSRD and CFP are examined. The results show that the more CSR information is disclosed, the better the CFP will be. However, such relationship is totally mediated by media exposure. This new finding not only enriches and expands the theory framework of CSR and CSRD, but also significantly enlightens business managers who make plan based on principles of strategic CSR during the process of relative strategy development. References | Related Articles | Metrics

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Research on Consumer Decision-Making Relationships and Individual Network Zhou Yan-li, Zhao Bing-xin 2013, 21 (4):  171-177.  Abstract ( 2363 )   PDF (1388KB) ( 2401 )   Save The network effect of consumer decision-making make the consumer decision-making embedded in the network limited by some specific factors, and the network structure will affect the decision-making behavior of consumers and the state of consumer macrostructure. The new analysis method, which called consumer decision-making networks, is to abstract and topology consumer decision-making network with graph, and then studied the differences in the nature of the network topology and their impacts on consumer decision-making. It provides a new framework and model to describe and handling complex consumer decision-making for study the consumer decision-making network effect systematically. In this paper, some intensive research on the relationship between consumers based on a preliminary study is done. The relationship between consumers is the key factor and foundation to the formation of consumer decision making network, and only understand how the consumers relate, then further study about the network's structural characteristics and their impacts can be carried on. Further to describe the relationship of consumer, the consumer decision-making individual network is proposed to studied the connotation and structure indicators of it. Finally, an example of the influence of network size of CDMIN on consumer decision-making and the market is simulated.A theoretical basis and simulation verification method for the follow-up study of consumer decision-making total network, as well as the consumer decision-making network effect are provided in this study. References | Related Articles | Metrics

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Case-based Reasoning with Optimized Weight for Software Cost Estimation Based on Generalized Fuzzy Number Wu Deng-sheng 2013, 21 (4):  178-186.  Abstract ( 2637 )   PDF (1140KB) ( 2180 )   Save In the software development process, accurate estimation of software effort is of great significance for software project and the enterprise. In order to overcome the difficulties that there isn't an accurate number for new software project at early stages according to the attributes of history project dataset and the existing software effort estimation models can't deal with the fuzzy number effectively, case-based reasoning and generalized fuzzy number are integrated, and a case-based reasoning (CBR) model based on generalized fuzzy number is proposed for software effort estimation in this paper. The traditional similarity measure such as Euclidean distance is replaced by a new similarity measure based on generalized fuzzy number in CBR model. Furthermore, the fuzzy c-means clustering is applied to fuzz the accurate number in history project dataset. Moreover, particle swarm optimization (PSO) is employed to further optimize attribute weights of the model. Finally Desharnais data is adopted to examine the validity of the model. It is shown that the proposed generalized fuzzy numbers CBR model can improve the estimation accuracy in comparison with the commonly used Euclidean distance CBR. In addition, it is also shown that the model with optimized weight from PSO can improve the estimation accuracy. References | Related Articles | Metrics

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Research on the Open Vehicle Routing Problemof with Simultaneous Deliveries and Pickups ZHANG Jiang-hua, LI Jin, GAO Min-Gang 2013, 21 (4):  187-192.  Abstract ( 2256 )   PDF (857KB) ( 2342 )   Save Open vehicle routing problem of multiple distribution centers with simultaneous deliveries and pickups is studied, in which the number and working time of the vehicles are limited. Based on the minimum number and travel distance of vehicles, a multi-objective model is proposed. A novel mixed algorithm based on lagrangian relaxation technique and tabu search algorithm is given, which obtains the maximum lower bound of the optimal solution and then adopts the strategy of assignment and adjustment for clients to achieve the feasible solution. For the tabu search algorithm, a random neighborhood ordering and perturbation mechanisms based on four neighborhood search methods are employed. Computational results show that this algorithm is effective to search the satisfactory solutions and the open collaborative arrangement of vehicle routing is more economic and reasonable than the close independent arrangement of vehicle routing. References | Related Articles | Metrics