ON IMPROVING AN INTEGRATED INVENTORY MODEL FOR A SINGLE VENDOR AND MULTIPLE BUYERS WITH A RELAXED MATERIAL ORDERING CYCLE POLICY

1. Introduction With the development of information technology and the increasing market competition, simultaneously reducing inventory costs of raw materials, work-in-process, and finished items in different stages has become a major focus for supply chain management. Industrial practice and academic research have shown that VMI (Vendor Managed Inventory) can improve supply chain performance by decreasing inventory levels and costs. VMI is a collaborative business initiative where the vend…     

Technical Note ：SINGLE-PERIOD TWO-PRODUCT INVENTORY MODEL WITH SUBSTITUTION： SOLUTION AND PROPERTIES

In this paper, we study a single-period two-product inventory model with stochastic demands and downward substitution. The optimal order quantities are presented and some properties are provided. Comparing with newsboy model, we prove that both the profit and the fill rate can be improved by using the substitution policy. This work was supported partly by NSFC/RGC Joint Research Program under grant 79910161987 and the National Science Foundation of China (79825102, 70231010, 70321001). Lianqiao CAI is lecturer of School of International Business, Beijing Foreign Studies University. He received his B.S. and M.S. from School of Economics and Management, Tsinghua University, in 1995 and 1998, and Ph.D of Management Science from Tsinghua University in 2002. His research areas include supply chain management, optimization techniques. Jian Chen is Professor and Chairman of the Management Science Department and co-director of the Research Center for Contemporary Management, Tsinghua University. He has over 80 papers published in some leading international journals and first class Chinese journals, and has been a principal investigator for over 20 grants or research contracts with National Science Foundation of China, governmental organizations, and companies. His main research interests include supply chain management, E-commerce, modeling and control for complex systems, decision support systems and information systems, and forecast and optimization techniques. He serves as associate editor of the “IEEE Transactions on Systems, Man and Cybernetics: Part A” and “IEEE Transactions on Systems, Man and Cybernetics: Part C”, and on the Editorial Board of “The International Journal of Electronic Business” and “System Research and Behavioral Science”. He is the recipient of the Outstanding Contribution Award of IEEE Systems, Man, and Cybernetics Society in 1996, and the Young Scientist Award of China in 1992. He was Secretary General of the 1996 IEEE International Conference on Systems, Man, and Cybernetics in Beijing, Co-chair of the IPC of 1998 International Conference on Systems Science and Systems Engineering, Chair of the First Asian eBiz Workshop in 2001, Co-chair of the Asian eBiz Workshop in 2002 and 2003, and Co-chair of the international conference on Global Supply Chain Management in 2002. Houmin Yan received his B.S. and M.S. from the Department of Automation, Tsinghua University, in 1982 and 1985, respectively, and his Ph.D. from the Faculty of Management, University of Toronto in 1993. From Jan. 1994, he is with the Department of Systems Engineering and Engineering Management, the Chinese University of Hong Kong as an Assistance, Associate and Full Professor. He was a tenured Associate Professor at School of Management, the Univ. of Texas at Dallas. His main research areas are operations management, stochastic models, simulations, and supply chain management. He has published in journals such as Operations Research, Manufacturing and Service Operations Management, Production and Operations Management, Journal of Optimization: Theory and Applications, IIE Transactions and IEEE Transactions. He consults several high-tech companies, such as Motorola, C&K Systems, and Oriental Power, on issues spanning from production planning and scheduling, supply chain management to business process re-engineering. He is a member of INFORMS.     

Comparative analysis on traditional procurement and e-procurement strategy of supply chain

With increasingly intense competition between enterprises, the realization of advanced supply chain management has become an exquisite premise for the survival of firms. Procurement management is an important means to reduce costs and to enhance the competitive advantage. By exploiting the single period newsvendor model, this paper analyses and compares the benefit mechanisms of e-procurement and traditional procurement to quantify the effect of the Internet on supply chain procurement management in a neutral e-market. This work was partly supported by the National Natural Science Foundation of China under Grant No. 70125004 and 70572050. Guangshu Chang is a lecturer of Zhengzhou Institute of Aeronautics. He received his master degree from Zhengzhou University in 2000. His research interests include e-commerce, supply chain management and quality management. Jichao Xu is a professor of Zhengzhou Institute of Aeronautics. His research interests include quality management and quality engineering. Jianfeng Yang is a PhD student of Management School, Northwestern Polytechnical University. His research interest includes quality management. Jinfeng He is a PhD student of Management School, Northwestern Polytechnical University. Her research interest includes quality management. Li Zhang is a PhD student of Management School, Northwestern Polytechnical University. Her research interest includes quality management.     

Simulating the supply disruption for the coordinated supply chain

There are many disruptive accidents in the supply chain operations system and achieving the coordination of supply chain is main objective for supply chain research. While disruptive accidents have increasingly influenced the coordinated operation of the supply chain, existing research literature on the supply chain coordination is setting in a stationary environment. The answer for how the disruptive accidents affect the coordinated supply chain is given in this paper. Based on the benchmark supply chain which is coordinated by the negative incentive mechanism, we study the impacts of supply disruption on the supply chain system by using simulation approach in which two different distribution function of random variable are used to express the supply disruption. Comparison between these two simulation results and possible coordination mechanism under the supply disruption are proposed. From the perspective of supply chain risk management, we provide the inspiration for the manager.     

STUDIES ON HORIZONTAL COMPETITION AMONG HOMOGENOUS RETAILERS THROUGH AGENT-BASED SIMULATION

1. Introduction A supply chain is a network composed osuppliers, manufacturers, retailers, etc., whichcooperate to offer a kind of goods or servicesThese supply chain members cooperate andcompete with each other to maximize theiown profits. For example,…     

PERSPECTIVES ON URBAN WATER INFRASTRUCTURE IN CHINA FOR THE 21^ST C0ENTURY： SDMUWEIC MODEL

Based on system dynamics approach, SDMUWEIC model is developed in order to evaluatefuture dynamics of urban water infrastructure development in China. Firstly, this paper presents thebasic structure and characteristics of the model, focusing on water infrastructure‘s dynamicrelationships with population increase, economic development, water resources shortage and waterconservation practices. Secondly, model veracity and robustness tests based on behavior reproductionand uncertainty analyses are illustrated. Thirdly, based on the model, future pattems of China‘s urbanwater infrastructure investment requirements are simulated, and effectiveness of two different policyscenarios are evaluated. Finally, conclusion,; and policy implications are drawn, allowing insights intoChina‘s sustainable water infrastructure policies and managements.     

ON INVENTORY STRATEGIES OF ONLINE RETAILERS

1.Introduction This research focuses on online retailers(etailers,hereafter)who engage in the sale of physical goods.In general,the order fulfillment process of such an etailer can be depicted by Figure1.As presented in Figure1,a customer will place an order at the etailer’s website.Upon receipt of each order,the etailer will confirm whether or not stock is available to fulfill the order.Assuming that inventory is indeed available,the order will be packaged,after which it will be delivered …     

A NOTE ON THE STOCHASTIC ROOTS OF STOCHASTIC MATRICES

In this paper, we study the stochastic root matrices of stochastic matrices. All stochastic roots of2×2 stochastic matrices are found explicitly.A method based on characteristic polynomial of matrix isdeveloped to find all real root matrices that are functions of the original 3×3 matrix, including allpossible(function)stochastic root matrices. In addition, we comment on some numerical methods forcomputing stochastic root matrices of stochastic matrices.     

A situation calculus based approach to dynamic management of e-business services

In the era of e-businesses, the traditional business services are greatly challenged by the ever-increasing demands from customers with various backgrounds and personalities. Large numbers of new e-businesses are driven by the needs of customers. The existing dynamics inherent in the customer needs require the corresponding dynamic management of services. Attempting to respond to customers in a rapid and intelligent way, this paper proposes a situation calculus based approach for dynamically managing e-Business services in the ubiquitous environment. By employing the formalism of the situation calculus to enable intelligence and automation, the approach can implement. the functions of service automatic composition and model verification. These functions will improve the degree of customer-orientation and enable fast responsiveness in the emerging e-service systems.     

A perishable inventory system with service facilities, <Emphasis Type="Italic">MAP</Emphasis> arrivals and <Emphasis Type="Italic">PH</Emphasis> — Service times

We consider a continuous review perishable （s,S） inventory system with a service facility consisting of a waiting hall of finite capacity and a single server. We assume two types of customers, ordinary and negative, arrive according to a Markovian Arrival Process （MAP）. An ordinary customer joins the queue and a negative customer instead of joining the queue removes one ordinary customer from the queue. The removal rule adopted in this paper is RCE （removal of a customer from the end）. The individual customer＇s unit demand is satisfied after a random time of service which is assumed to have a phase-type distribution. The life time of each item and the lead time of the reorders have been assumed to be independent exponential distributions. The joint probability distribution of the number of customers in the system and the inventory level is obtained for the steady state case. Various stationary system performance measures are computed and the total expected cost rate is calculated. The results are illustrated numerically.     

电子市场环境下需求不确定供应链多目标鲁棒运作模型

建立电子市场环境下由多个供应商，多个具有不确定需求的顾客构成的供应链运作模型。供应链中的供应商既可以通过电子市场又可以直接将多种产品供应给不同的顾客。采用已知概率的情景集合描述顾客的不确定需求，利用基于情景分析的鲁棒优化方法建立供应链的运作模型。该模型为一个多目标规划问题，满足诸如尽可能达到顾客需求，系统的总成本最小，供应商的加工能力使用率不低于某一指定水平，对应于不确定需求的决策的鲁棒性等多个相互冲突的目标。数值仿真结果表明，模型的解是最保守的，但却能够有效地保证供应链运作的鲁棒性。     

AN AHP MODEL FOR BRINGING EXPERTS TO CONSENSUS ON MEDICAL PAYMENT STANDARDS

1. Introduction Many countries with health insurance systems conduct periodic payment standardsadjustments. The main reasons are to address continually rising health care costs and to ensure an equitable allocation of resources. From the248 JOURNAL OF SYSTEMS SCIENCE AND SYSTEMS ENGINEERING data of the Organization for Economic Co-operation and Development (OECD) countries, the proportion of health care costs as a percentage of Gross Domestic Product (GDP) continues to r…     

面向重要供应商和客户的供应链设计方法

与重要供应商和高价值客户建立良好的关系，已经成为企业获得竞争优势的必然选择。本文从供应链核心企业的角度出发，提出了一种面向重要供应商和客户的供应链设计方法。该方法将供应链设计分成两个阶段。首先，利用模糊综合评判法对核心企业的供应商和客户进行评价，获得它们的重要度。然后，建立一个多目标混合整数规划模型来描述供应链设计问题。与基于成本最小化或利润最大化的传统供应链设计模型相比，该模型体现了关系管理的思想，考虑（1）优先向具有较高重要度的供应商采购原料，以建立长期稳定的合作关系。（2）分销中心的选址要尽量接近重要的客户或客户区，以缩短订货的提前期，提高客户服务水平。     

MULTILATERAL COMPARISON ON CHINESE MANUFACTURING＇S INTERNATIONAL COMPETITIVENESS

This paper analyses Chinese manufacturing performance from a multilateral perspective in 1980–2004. The PPPs, relative price levels, labor productivity and ULCs in multilateral comparison are used to explore Chinese manufacturing competitiveness. The PPPs are based on the benchmark year 1997. These results are compared to the previous estimates based on the 1987 benchmark. The findings are as follows: the PPPs derived by the different approaches in the base year 1997 in Chinese manufacturing are approximately 3.7 yuan/international $. Since the middle 1980s, China’s relative price level has been the lowest among all five countries and declined during the period of time. Its ULC has also been declining with some fluctuation. In the 1980s, there was “no catch-up rapid growth” in its labor productivity. However, after 1992, a beginning has been made with catch up distinctly, though from a very low level. This work was supported by the National Natural Science Foundation of China under Grant 70173029, 70571004 and 70531010. Ruoen Ren Professor of School of Economics & Management in Beihang University received Ph.D. in Economics in Renmin University of China in 1987. As one who enjoys the Government Special Allowance, he specializes in the study of international competitiveness, macroeconomics analysis, input-output table research, and credit risk management etc. His primary academic achievements are as follows: ICP in China, ICOP in China, KLEMS in China, Credit risk management in China commercial bank. In addition to his teaching and research at school, he is a chief economist in China Development Bank, a member in Science & Technical committee in Ministry of Education, and an executive director in China’s Input-output Association, etc. Haitao Zheng Doctorial candidate of School of Economics & Management in Beihang University, majors in the study on international competitiveness and insurance actuary. Meanwhile, he is an Associate of Society of Chinese Actuary.     

Data crystallization applied for designing new products

It is only the observable part of the real world that can be stored in data. For such incomplete and ill-structured data, data crystallizing aims at presenting the hidden structure among events including unobservable events. This is realized by data crystallization, where dummy items, corresponding to potential existence ofunobservable events, are inserted to the given data. These dummy items and their relations with observable events are visualized by applying KeyGraph to the data with dummy items, like the crystallization of snow where dusts are involved in the formation of crystallization of water molecules. For tuning the granularity level of structure to be visualized, the tool of data crystallization is integrated with human＇s process of understanding significant scenarios in the real world. This basic method is expected to be applicable for various real world domains where previous methods of chance-discovery lead human to successful decision making. In this paper, we apply the data crystallization with human-interactive annealing （DCHA） to the design of products in a real company. The results show its effect to industrial decision making.     

The M/M/1 queue with working vacations and vacation interruptions

In this paper, we study the M/M/1 queue with working vacations and vacation interruptions. The working vacation is introduced recently, during which the server can still provide service on the original ongoing work at a lower rate. Meanwhile, we introduce a new policy：, the server can come back from the vacation to the normal working level once some indices of the system, such as the number of customers, achieve a certain value in the vacation period. The server may come back from the vacation without completing the vacation. Such policy is called vacation interruption. We connect the above mentioned two policies and assume that if there are customers in the system after a service completion during the vacation period, the server will come back to the normal working level. In terms of the quasi birth and death process and matrix-geometric solution method, we obtain the distributions and the stochastic decomposition structures for the number of customers and the waiting time and provide some indices of systems.     

CUSTOMER EQUITY： MAKING MARKETING STRATEGY FINANCIALLY ACCOUNTABLE

1. Introduction The long-term value of a firm is largelydetermined by the value of the company’scustomer relationships, which result in thefirm’s ‘customer equity’ (Blattberg andDeighton 1996), defined by Rust, Lemon andZeithaml (2000, p.4…     

INCREASING RETURNS TO SCALE,DYNAMICS OF INDUSTRIAL STRUCTURE AND SIZE DISTRIBUTION OF FIRMS

1. Introduction In the past decades, the evolutionary perspective has contributed lot to the economics (Arthur and Durlauf et al 1997, Dosi and Nelson 1994, Aruka 2001). The economy is studied as an evolving complex system with many features in complexity such as nonlinear interactions and emergent properties. In reality, the economic system consists of many adaptive agents. They learn from each other, and their values may be influenced by others’ values and actions. These interactions amo…     

MODELING JUMPS IN RETURNS OF FINANCIAL ASSETS AS M4 PROCESSES： MEASURED EXCHANGE RATE EXPOSURE OF ASIAN EQUITY PORTFOLIO

1. Introduction An early analysis of exchange rate changes and share prices found that the general stock market index tended to move up (down) immediately after a devaluation (revaluation) of the local currency (Giddy 1974). It is surprising that previous researches (Jorion 1990; Amihud 1993; Bodnar and Gentry 1993) find that no contemporaneous relationship between exchange rate changes and excess equity market returns of largest U.S. exporting firms. Recently, it has argued that there is a…     

Estimation of chain reaction bankruptcy structure by chance discovery method — With time order method and directed KeyGraph

Chain reaction bankruptcy is regarded as common phenomenon and its effect is to be taken into account when credit risk portfolio is analyzed. But consideration and modeling of its effect leave much room for improvement. That is mainly because method for grasping relations among companies with limited data is underdeveloped. In this article, chance discovery method is applied to estimate industrial relations that are to include companies＇ relations that transmit chain reaction of bankruptcy. Time order method and directed KeyGraph are newly introduced to distinguish and express the time order among defaults that is essential information for the analysis of chain reaction bankruptcy. The steps for the data analysis are introduced and result of example analysis with default data in Kyushu, Japan, 2005 is presented. The structure estimated by the new method is compared with the structure of actual account receivable holders of bankrupted companies for evaluation.