Small and medium-sized manufacturing enterprises have played an important role in developing Japan's manufacturing industry. However, Japanese small and medium-sized manufacturing enterprises are currently faced with various difficulties in their business environment and are seeking ways to resolve the deadlock. In response, Mitsubishi Research Institute, Inc. has proposed a new methodology called “the management strategy on expert skills,” which regards expert skills as important management resources that bring benefits to each company in terms of not only production but also sales. This paper aims to verify the validity of “the management strategy on expert skills” in small and mediumsized manufacturing enterprises through an analysis of the results of our questionnaire survey of these enterprises. The composition of the factors extracted using factor analysis is consistent with the theoretical procedure of “the management strategy on expert skills,” which was proposed previously. Moreover, the comparative analysis between companies whose sales are increasing and those whose sales are decreasing shows the validity of “the management strategy on expert skills” and clarifies important management actions such as “the appeal of skills accumulated in the company,” “recognition of training and effective use of the skills as a management issue” and “intensive investment in core skills.”

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Outpatients in Japan are generally divided into two groups: scheduled patients and walk-ins. Each scheduled patient arrives at a hospital with an appointment. On the other hand, walk-ins arrive at a hospital unexpectedly. In general, the ratio of walk-ins to all outpatients is considerable. This paper focuses on the average waiting times of both scheduled patients and walk-ins under a fixed set of scheduled patients, and deals with the consultation sequencing problem. Even though the average waiting time for all patients is the same under a set of candidate sequences, the average waiting time of scheduled patients (and also that of walk-ins) usually depends on the sequence. Therefore, to realize the target average waiting times, there is a requirement to appropriately allocate the total waiting time of all patients between the two groups. The relationship between the waiting times of these two groups is approximated by a linear equation of which the coefficient is given by the average number of patients and the mean consultation time of each group. This paper also tries to visualize the planned consultation sequence to alleviate the stress of waiting. The planned sequence may include one or more reserved slots for scheduled but not yet arrived patients, and open slots for walk-ins. Each waiting patient can grasp the minimum and maximum number of patients in front of him or her in the sequence. When a scheduled patient arrives he or she is placed at one of the reserved slots. When a walk-in arrives, an open slot for the patient is selected randomly. The types of slots, however, are invisible to the patients. To evaluate the proposed method, four alternative selection rules are prepared. Each rule selects a patient dynamically when a physician becomes ready for the next consultation. The comparison of the proposed method with alternative dynamic selection rules via simulation experiments indicated that the performance of the proposed method is similar to the alternative rules in terms of the average waiting times.

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This paper addresses a design problem of disassembly and sorting systems in which collected products are disassembled into parts and the parts are sorted into several groups according to the usage method. The disassembly operations are allocated to workstations and the necessary tools are arranged at the workstation. One of the important operations after disassembly is to sort the obtained parts. In general, products consist of many kinds of parts, and the sorting operations are troublesome tasks for the workers. Several boxes are arranged at each workstation and the parts are sorted into the boxes by the workers. The decision variables in the design of the system are the number of stages, the number of workstations in each stage, the allocation of disassembly and sorting operations to the workstations, and the arrangement of disassembly tools and sorting boxes at each workstation. The design problem is formulated as an integer programming problem under a cost-minimization criterion. The problem is solved using the CPLEX optimization software. Numerical experiments are implemented for two types of precedence relationships (the complete serial type and complete parallel type), and the characteristics of the optimal disassembly and sorting system are shown for the precedence relationships. Further, optimal solutions are calculated for the data for cellular phones and personal computers, and it is shown that multistage parallel-station systems are superior to both multistage non-parallel systems and single-stage parallel systems.

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Development and innovations in manufacturing techniques have changed the nature of manufacturing activities from manual to automatic. However, tactile inspection has still not been automated. Tactile inspection requires upper limb work involving repetitively touching the surface of objects. It is important to clarify the factors influencing workload because repetitive upper limb work causes damage to the hands, arms and shoulders. Nevertheless, there are few studies about workload during tactile inspection. In this paper, we investigate the effect of object orientation and scanning direction on upper limb load during tactile inspection. Eleven healthy male subjects participated in this experiment. They were asked to inspect objects using a combination of six object orientations and two scanning directions. The six object orientations were the frontal plane, the sagittal plane, the horizontal plane, the middle orientation between the frontal and sagittal planes, the middle orientation between the sagittal and horizontal planes, and the middle orientation between the horizontal and frontal planes. The scanning directions were the horizontal and vertical directions. The upper limb activities were measured by performing electromyography. We also measured the control force using a load cell. Furthermore, subjective indices for burden, difficulty of the task and inspection were investigated. Electromyography was performed at the upper part of the trapezius muscle, at the clavicular part of the pectoralis major muscle, at the middle part of the deltoid muscle, at the biceps brachii muscle, at the triceps brachii muscle and at the extensor carpi ulnaris muscle. The results showed that tactile inspections in the frontal plane condition and in the middle orientation between the horizontal and frontal plane condition are undesirable because these conditions cause excessive load on the extensor carpi ulnaris muscle due to extension of the wrist. Furthermore, the load on the shoulder and elbow decreases in the horizontal plane condition and in the middle orientation between the horizontal and frontal plane condition, and increases in the sagittal plane condition.

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In this paper, we present a new heuristics for the facility layout problem (FLP). It is known that the FLP can be solved to optimality via mixed integer programming (MIP). The largest problem that has been solved to optimality to date, however, contains only eleven departments, and thus, is not applicable to typical problems where there are many more departments. In this paper, we developed a new force-directed model that enables us to develop good relative locations of departments very quickly by exploiting the special structure of the problem. We used the chaos characteristics of the force-directed model used in the algorithm so that they do not become stuck as a result of the local optima. We use this relative position to formulate the FLP as linear programming. In the computational experiments, we tested our proposed method against several well-known benchmark data sets. Our algorithm shows better or equal cost performance in most of them, and also finishes the computations much faster.

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The classical assignment problem has been widely applied in span manufacturing, personnel scheduling and transportation, to name just a few areas. Generally, the problem seeks to minimize the cost of assigning a given set of jobs (tasks) to a group of machines (worker). Computationally, the assignment problem is considered “easy” because it can be solved in polynomial time using several efficient algorithms. In this paper, we use a limited-cycle model with multiple periods where the risk itself is also affected greatly by the risks which existed in the earlier periods, and we focus on the property of the optimal assignment with minimized total expected risk (cost) in the limited-cycle model. First, the reset model, a simple model of the limited-cycle model, is presented. Then, the optimal assignment problem under the reset model is defined. After that, the property of the optimal assignment with two special workers is proposed. Finally, the property is proved using a mathematical approach and investigated via numerical experiments with a program in which an algorithm based on the branch and bound method is used.

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This paper describes a case study for improving the productivity of distributive processing in a distribution center. The improvement of productivity was required to respond to the growth of the mail-order business. Distributive processing consists of picking, sorting, checking and packing. First, a work analysis was implemented and it was shown that the detailed work of checking had been preventing the distributive processing from boosting output. In this process, items were all checked by hand using bar-code scanners. Two systems, an automatic checking system using RFID and an assortment system, were considered for introduction in order to improve the flow of work at the bottleneck. Field tests were conducted using these two systems. The result of the field tests showed that both systems were able to resolve the bottleneck. However, the assortment system was eventually chosen because it does not overlook items and allows 100% accuracy of assortment. Additionally, reassignment of workers was carried out in order to balance out work load and to resolve the new bottlenecks. In the end, the productivity of the distributive processing was improved 42% three month later.

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Given that the mobile phone market in Japan is mature, it is a constant struggle for mobile phone carriers to prevent loss of their customers to other carriers, a process known as churning. To offer their customers incentives, mobile phone carriers distinguish between profitable customers and unprofitable customers and give preferential treatment, such as large discounts, to profitable customers. However, as of yet, mobile phone carriers have not been able to stop churning completely. Mobile phone carriers can use various types of transaction data such as web access history data and search words. These data are thought to reflect the preferences of customers. However, it is also a fact that carriers still cannot use these data for their own management strategies because of restrictions in the Private Information Protection Law and the Telecommunications Industry Law. In this study, we focus on web access history data and propose a method of effectively finding relationships between websites visited and churning. We also try to improve the accuracy of the prediction model for churning using web access history data.

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This study proposes eight transaction patterns aiming to reduce exceptions causing the executor's “decline” of the initiator's “request” (order). In business organizations, quite a few of these exceptions occur, and quite a lot of time and energy are wasted in coping with such exceptions. Sometimes, the exceptions may also cause a decrease in customer satisfaction due to the deference of the clerks who cope with them. Nonetheless, there seem to have been few useful solution patterns suggested by those working on business process modeling to avoid such exceptions. Hence in this paper, we make an attempt to create transaction patterns to reduce the number of such exceptions. Specifically, eight transaction patterns for avoiding the “decline” of the executor against the “request” (order) of the initiator are theoretically derived from the viewpoint of the relationship between actors who join a transaction, which depends upon the “language action perspective.” Moreover, these eight transaction patterns derived are practically verified through application to a certain service company in Japan. The results show that these eight transaction patterns derived are verified by the existence of all eight patterns in the company. Therefore, this also suggests that the “language action perspective” can be used as a solution to solve the defect of business process flexibility, which is too complicated to understand when described in the context of comprehensive business processes in an enterprise.

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For some production industries, in order to accommodate diversified customer needs and shortened product lifecycles, job-order production and quick delivery are required. In production schedules that determine the amount of production, there is trade-off relationship between the meeting due date and productive efficiency. However, the relationship changes according to daily changes in the work in process in the case of high-mix production companies. This study thus proposed a method to: 1) extract four parameters which affect the balance of both factors, 2) change the parameters and make a production schedule, 3) put the due date and productive efficiency into indices, 4) assess the balance based on a simulation with the parameters and 5) use a graph which shows the results of the production schedule. The four parameters are: 1) the number of days for producing at a given time, 2) how to deal with the same parts for the following ten days, 3) how to deal with unfinished parts in the preceding process and 4) the method of producing at a given time. In addition, the effectiveness of the proposed method is verified using the data of a target company. The results show that the rate of the meeting due date can increase by 23.8% when the rate of productive efficiency decreases by only 1.0%.

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Product functions and structure of parts are ordinarily considered in a process of modular design. If environmental characteristics were evaluated with regard to the parts and structure of products in the process, designed modules could be used for recycling or reuse. However, since modules designed by considering environmental characteristics of products or parts depend on the materials or strength of parts, the modules are naturally different from modules designed by considering product functions. Furthermore, it is difficult to generate modules by considering product functions and environmental characteristics simultaneously.
In this study, a method of modular design including simultaneous evaluation of product functions and environmental characteristics is proposed. The proposed method consists of two processes: a process to cluster parts using information of functions and environmental characteristics independently, and a process of combining modules designed independently. In the modular design including evaluation of product functions, the functions and design structure matrix (FDSM) is introduced and a genetic algorithm is applied to cluster parts. FDSM is a table of relationships of product functions and parts. On the other hand, the self-organizing map (SOM) is applied to cluster parts in modular design including evaluation of environmental characteristics of parts. Several rules and e-BOM are applied to generate modules while comparing these different types of modules as new modules including evaluations of both functions and environmental characteristics. This paper presents characteristics of the proposed method of modular design and a case study of the method applying modular design to a mouse including a ball.

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