This paper proposes a new physical distribution model to express a mixed system of direct and relay delivery methods from the manufacturer to the shop. The direct and relay delivery methods should be selected and appropriately applied depending on the situations. However, a system with the intermediate characteristics of these two methods may be effective for some settings in practice and is proposed in this paper. This method is based on an analogy of the milk-run distribution method. Milk-run logistics is a method such that the manufacturer's trucks begin at the factory, move to suppliers, collect parts at each supplier's plant, and return to the factory instead of the usual distribution by suppliers. Though milk-run logistics is an effective method as an inbound logistics system, this paper identifies how an effective distribution system can be constructed for outbound logistics. A basic system model is shown for a distribution model with three layers, including an analysis of the model by Z transform. From the numerical examples, the effectiveness of the proposal is clarified. In the proposed system, the variances of inventories in the relay distribution center and shop can be reduced.

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We propose a new approach to optimize facility layout and buffer space allocation for production systems with a feed-forward configuration and variable processing times. Our objective is to efficiently find Pareto-optimal solutions for both throughput and material handling cost. We assume that work transfer is performed by conveyor belt or unlimited vehicles. Since the facility layout does not affect the throughput under these assumptions, we first calculate the throughput for every buffer space allocation using Markov analysis. Then the set of Pareto optimal facility layouts and buffer space allocations is searched using a genetic algorithm. Numerical examples illustrate the proposed approach.

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In today's business environment, we are faced with some problems from the viewpoint of ecology; one important problem being the reuse of used products. Used products are generally collected and stored as reusable resources. The remanufacturing production system meets the demand by remanufacturing products utilizing reusable resources in addition to the production of new products. In this case, the flow of reusable resources is called reverse-logistics in contrast to the flow of demand. Naturally, the optimal production policy of the remanufacturing production system with reverse-logistics should be considered. In this article, we formulate a build-to-order remanufacturing production system using the open queueing network theory. The production cost, penalty cost for the delay of due date, and holding cost of used products collected as reusable resources are evaluated using the open queueing network theory. Then, the optimal production policy for manufacturing and remanufacturing using the build-to-order remanufacturing production system is investigated.

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To compete successfully in today's marketplace, it has become apparent that success cannot rely solely on improving the efficiency of internal operations, and that collaboration with trading partners can build the foundation for a competitive advantage and substantially improve the bottom line. Companies need to efficiently manage the activities of design, manufacturing, distribution, service and recycling of their products, and services to their customers. The coordination and integration of these flows within and across companies are critical in effective supply chain management (SCM). Demand management is critical in a supply chain involving multiple companies. Often, supply chains are subjected to information distortion as demand information is processed and passed on from one part of the chain to another. The propagation of demand variability up the supply chain, a phenomenon in the industrial world known as the "bullwhip" or "whiplash" effect, is a subject of research interest. In this paper, first, we define a two-stage supply chain model (a retailer and a supplier). Based on the results of simulations, we identify the factors which affect the degree of the bullwhip effect. As a result, we noted that the factors affecting the bullwhip effect are lead time, level of safety stock, and length of period to calculating moving average, whereas demand average and variance do not. Furthermore, when one of the above factors varies, decision makers may alter other factors to adjust to the change. Here, we also investigate how such decisions affect the degree of the bullwhip effect.

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This study evaluates a new business model that realizes cost and benefit sharing in RFID (Radio Frequency Identification) applications. In the model proposed in this study, the author assumes that one supplier sells goods to a retailer that has two identical stores, which share real-time item level inventory information and transship goods in order to meet local customer demands. Assuming that the demand pattern follows a single-period stochastic problem, the author shows that this model increases the optimum quantity that will maximize expected profits to each store and generates more profits for both the supplier and retailer. The author also shows that the profit of the retailer does not improve when he takes handling cost between stores into consideration and the handling cost reaches its upper boundary, but that the profits of both the retailer and supplier improve even in the upper-boundary situation if the supplier covers part of the transshipment cost. The result indicates that RFID implementation benefits all the supply chain channel members and that information sharing among these members is promoted when using the proposed model.

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In recent years investors have began to observe socially responsible investment (SRI) and selecting companies that are evaluated highly in this respect over those performing well in the area of corporate social responsibility (CSR). However, investors' needs or value judgments do not fully reflect present SRI screenings. In this study, the authors clarify the problems related to investment selection and decisions for present SRI screening selection ratios, and introduce a new model the resolves the problems related to determining investment selection ratios. Specifically, assuming a set with an undefined border (fuzzy set), we consider the fuzzy entropy expressing an unspecified amount of information. Then we introduce a model of a multifactor information channel weighted using fuzzy entropy. This model briefly expresses the decision-making process of the investment selection ratios, which reflects investors' value judgments in evaluation weights, thereby showing both sides of the human self-seeking selection action (randomness+fuzziness: fuzzy entropy) and satisfaction (average characteristic value) regarding the quality of the CSR characterized in each investment (alternatives). Using questionnaires, we estimate the SRI selection ratio, and examine and compare the proposed model with actual selection ratios.

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The operation time of multi-step assembly tasks is affected by work difficulties. When an assembly process includes difficult operations, a long processing time is required to complete all operations. Therefore, considering operation difficulties in the task is required to accurately predict the operation time of an assembly task. Our previous paper shows that the operation time in multi-step assembly tasks is affected by a combination of work difficulties such as worker's posture, worker's status of supports for a semi-final product, and the number of bolts required to affix the parts. In this paper, we review a problem for determining the operation sequence of an assembly task and propose a method to search for the optimal sequence by evaluating different types of work difficulties. The proposed method is based on a genetic algorithm and it includes a function to modify a standard operation time obtained using the MODAPTS method. A neural network is introduced to calculate the rating to modify the standard operation time. Evaluations of work difficulties are used as input data of the neural network to calculate the operation time of each operation separated in the sequence. To apply the proposed method, operations and worker motions appearing in an assembly process are categorized and related to each other. Then, the proposed method is applied to an actual assembly process to evaluate its performance. The results show that the best assembly sequences obtained by the proposed method give shorter operation times than the other sequences, and the operation times of the best sequences approximate to the measured operation times.

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A study was made on optimum greenhouse utilization for the production of cut rose flowers by family members and part-time employees. The following were assumed in this study: cut rose flowers are produced using rock wool culturing; year-round cropping (production system) is practiced for harvest mainly in the winter; and the same cropping type is repeated every year. In the data used for this study, heavy oil A is used as a fuel for heating greenhouses. The price of heavy oil A was much higher in the previous autumn as compared to that listed in this data. As the price of heavy oil A markedly increased, attention was paid only to the increment in the cost of heating fuel in this paper. A linear programming model was used to determine how to secure the agricultural income R_<BP> mentioned in the data against the increase in oil price. An optimum utilization plan was examined with respect to planting density, yield per stock, and monthly yield. I also studied how to save heavy oil A while maintaining an adequate temperature for the growth of roses in greenhouses in the winter in oder to secure agricultural income R_<BP>.

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The authors propose a method for improving service operations from the viewpoint of promoting correspondence between customers and service-providing corporations. The paper distinguishes the correspondence of various types of information and physical objects into unavoidable correspondence, correspondence that increases the customer satisfaction level, and correspondence that increases the service provider satisfaction level. Based on these distinctions, we propose a method to design the most efficient operation procedures, comprised solely of unavoidable correspondence, and to identify wasteful correspondence existing in current operation procedures from the viewpoint of gap between the two procedures. We then paper propose a framework to identify various alternative methods for increasing the satisfaction level of both customers and service providers respectively, and to realize these alternatives in the form of correspondence between customers and service providers. The proposed method of this hierarchical improvement framework is then applied to an actual case of a leasing operation at a consumer financing company, and the validity of the proposed method is discussed.

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