Journal of Japan Industrial Management Association
Online ISSN : 2187-9079
Print ISSN : 1342-2618
ISSN-L : 1342-2618
Volume 58 , Issue 5
Showing 1-15 articles out of 15 articles from the selected issue
  • Type: Cover
    2007 Volume 58 Issue 5 Pages Cover9-
    Published: December 15, 2007
    Released: November 01, 2017
    JOURNALS FREE ACCESS
    Download PDF (1810K)
  • Type: Cover
    2007 Volume 58 Issue 5 Pages Cover10-
    Published: December 15, 2007
    Released: November 01, 2017
    JOURNALS FREE ACCESS
    Download PDF (1810K)
  • Type: Index
    2007 Volume 58 Issue 5 Pages Toc5-
    Published: December 15, 2007
    Released: November 01, 2017
    JOURNALS FREE ACCESS
    Download PDF (44K)
  • Koji Watanabe, Kazuya Toizumi, Takashi Irohara
    Type: Article
    2007 Volume 58 Issue 5 Pages 333-341
    Published: December 15, 2007
    Released: November 01, 2017
    JOURNALS FREE ACCESS
    In this paper, we propose a heuristic algorithm for unrelated parallel machine scheduling problems. In an unrelated parallel machine, there is no particular relationship among processing times for each job since they are different depending on the machine. The processing times for the jobs assigned to one machine are not proportional to the processing times that correspond to another. The objective function is to minimize the total weighted tardiness and earliness for each job. An unrelated parallel machine scheduling problem can be divided into two problems: one is the assignment problem, which is to assign the jobs to machine types; and the other is the scheduling problem, which is to schedule the jobs on each machine type. In the proposed method, the former problem is solved by making a random initial solution at first. In the latter problem, we apply the Lagrangian decomposition and coordination method to each machine type. In the relaxed problem using the Lagrangian decomposition and coordination method, the machine capacity constraints are relaxed and the optimal values of the Lagrangian multipliers are searched by solving the Lagrangian dual problem using a subgradient algorithm. Then we solve the former problem again using the Lagrangian multiplier. The Lagrangian multiplier helps to solve the former problem because it represents the degree of congestion of jobs on the term. The series of operations is iterated to search for better solutions. Finally, computational experiments show that this approach can find better solutions than the comparative method based on Genetic Algorithm in various environments.
    Download PDF (1010K)
  • Hideki NAGATSUKA, Hisashi YAMAMOTO, Toshinari KAMAKURA
    Type: Article
    2007 Volume 58 Issue 5 Pages 342-352
    Published: December 15, 2007
    Released: November 01, 2017
    JOURNALS FREE ACCESS
    The gamma distribution, having location (threshold), scale and shape parameters, is used as a model for distributions of life spans, reaction time, and for other types of non-symmetrical data. It has been said that the inference for the three-parameter gamma distribution is difficult because of the nonregularity in maximum likelihood estimation in spite of the numerous papers have appeared over the years. On the other hand, the methodology for inference for the two-parameter gamma distribution has been established over the years. It is usual to avoid fitting the three-parameter gamma distribution and two-parameter gamma distribution to data in practice. In this article, we propose a new method for estimating the shape parameter of the gamma distribution based on data transformation free from location and scale parameters. The method is easily implemented with the aid of a table or graph. A simulation study shows that the proposed estimator performs better than the maximum likelihood estimator of the shape parameter of the two-parameter gamma distribution when the threshold exists even when it is close to zero.
    Download PDF (987K)
  • Masatoshi TANAKA, Shin'ichi YOSHIKAWA, Chhaing HUY, Eiji TAKEDA
    Type: Article
    2007 Volume 58 Issue 5 Pages 353-360
    Published: December 15, 2007
    Released: November 01, 2017
    JOURNALS FREE ACCESS
    To gain cost advantage and market share, many firms implement various initiatives such as outsourced manufacturing and product variety. These initiatives are effective in a stable environment, but they could make a supply chain more vulnerable to various types of disruption caused by uncertain economic cycles, consumer demands, and natural and man-made disasters. In recent years, manufacturers and retailers are implementing various policies to coordinate distribution channels more effectively. For example, there are buy-back policy, revenue-sharing policy, quantity-discount policy and so on. We consider a standard newsvendor problem in a single manufacturer and retailer, and deal with a mathematical programming problem to maximize the overall expected profit in the supply chain. It is shown that our model's policy can be completely eliminated "double marginalization". In previous papers, they were limited to only one policy. But in general, we must consider many contract policies to coordinate the overall expected profit in all domains of each member's expected profit. On the other hand, in previous papers, when all of the members in the supply chain applied the policy for uncertainty, they completely guarantee each other. However, we need not guarantee 100% for uncertainty. In this paper, we discuss supply chain coordination with gradual buy-back and revenue-sharing occurring simultaneously. The main results are obtained and illustrated by numerical examples.
    Download PDF (929K)
  • Shigenori KOTANI
    Type: Article
    2007 Volume 58 Issue 5 Pages 361-374
    Published: December 15, 2007
    Released: November 01, 2017
    JOURNALS FREE ACCESS
    There exist many studies for mixed-model sequencing problems. The goal of many of these studies is to level the workload at each workstation on the assembly line in order to minimize the line stoppage time. The sequencing method of the real mixed-model assembly lines of vehicles uses the total workload of each vehicle in order to level the workload at each workstation. This is the same as an assembly line having only one workstation. The reason for assuming the number of workstations in the vehicle assembly line is only one is as follows. It is very difficult to maintain the data for all of the processing time of each workstation because: (1) There are many workstations in vehicle assembly lines. Moreover, the number of specifications for a vehicle is very large. (2) Improvements in the operation of workstations and assembly line balancing are ongoing. Therefore, assembly line balancing is usually performed such that the workload at each workstation for each specification of a vehicle is kept constant as much as possible. As a result, the workload at each workstation can be leveled approximately, though the sequencing method uses the total workload of each specification for a vehicle, not the workload at each workstation. Consequently, we approach a sequencing problem for mixed-model assembly lines with only one workstation. There have been very few studies regarding this problem. Therefore, we have investigated it and obtained related characteristics. Specifically, we have obtained the necessary condition for an optimal solution. We propose an approximation algorithm using this condition. It is shown by numerical examples that the proposed algorithm can find an optimal solution for almost all sequencing problems.
    Download PDF (1517K)
  • Zhong LIN, Qunzhi WANG, De-bi CAO
    Type: Article
    2007 Volume 58 Issue 5 Pages 375-382
    Published: December 15, 2007
    Released: November 01, 2017
    JOURNALS FREE ACCESS
    This paper considers a supply contract in a two-stages supply chain consisting of a supplier and a buyer. Market demands are stochastic and have a short selling season. The leadtime of production and delivery is longer than the length of the selling season, and therefore the supplier has only one opportunity for production. The buyer commits an initial order at the beginning of production, purchasing a quantity of options, and later the buyer exercises and finalizes the option at the beginning of the selling season. A supply contract model maximizing the buyer's expected profits was proposed. In the model, a two-phase backward optimization process was introduced to obtain (1) the optimal excise quantity of the option at the beginning of selling season, and (2) the optimal initial order quantity and option quantity at the beginning of production. Closed forms of the solutions were derived analytically under the condition of uniform demand distribution, and performance was evaluated comparing expected profits with the well-known newsvendor model without options. The profitability of the model was analyzed under various parameter settings, and the results show that the proposed model always gives better performance compare to the traditional newsvendor model.
    Download PDF (875K)
  • JiaHua WENG, Masaharu BANNO, Hiroki OKUBO, Hisashi ONARI
    Type: Article
    2007 Volume 58 Issue 5 Pages 383-394
    Published: December 15, 2007
    Released: November 01, 2017
    JOURNALS FREE ACCESS
    The assembly line in question is a single-product line consisting of a set of workstations. In order to complete a product, various operations have to be processed, and technological precedence requirements exist among operations. Moreover, the processing time of a given operation differs largely among workers according to their work experience. Process planning for an assembly line includes not only operation assignment to line workstations (operation assignment sub-problem), but also worker allocation to the workstations (worker allocation sub-problem). The purpose of line process planning is to minimize the cycle time. In related research, we proved that a method where these sub-problems are considered separately cannot obtain a good result. In this paper, an integrated method based on a genetic algorithm is proposed to simultaneously solve these sub-problems. In order to improve solution searching efficiency through crossover, we propose a method which focuses on the operations/workers that are assigned/allocated to the workstations with high or low workloads. At the same time, in order to obtain a good local optimum, we also propose two logics to avoid searching within a narrow solution area so that good solutions may be found. They are the gene similarity checking logic for parent chromosomes, and the gene correction logic for the defective child chromosomes. Compared to the separate method, the effects of our integrated proposal are confirmed for both shortening cycle time and decreasing line balance loss.
    Download PDF (1421K)
  • Mitsumasa KUMAZAWA
    Type: Article
    2007 Volume 58 Issue 5 Pages 395-404
    Published: December 15, 2007
    Released: November 01, 2017
    JOURNALS FREE ACCESS
    Employee work satisfaction and fatigue feeling are important for companies to improve productivity. Recently, the problem of employees leaving their jobs early has become clear. In this study, the relation between female employee's work satisfaction and fatigue feeling was researched and analyzed. The subjects of this study were 30 newly employed women, who had graduated senior high school, and 28 experienced women in three companies. The objective works were sawing and fiber processing. Questionnaires given included an original questionnaire for work satisfaction consisting of 13 items, a questionnaire regarding "ikigai" feeling consisting of four items and the Questionnaire for Subjective Fatigue Feeling from the Industrial Fatigue Research Committee of Japan Association of Industrial Health. As a result, most subjective persons investigated tended to reply that the works were hard. As for the relationship between work satisfaction and fatigue feeling, it is presumed that the vision for the future of working life concerns with fatigue feeling. As for newly employed female employees, as a result of the classification of satisfied group and dissatisfied group of work, the former group felt less fatigue than the latter. As for experienced female employees who have visions for the future or "ikigai" of work felt less fatigue than others.
    Download PDF (1121K)
  • Yasunori Fujita
    Type: Article
    2007 Volume 58 Issue 5 Pages 405-408
    Published: December 15, 2007
    Released: November 01, 2017
    JOURNALS FREE ACCESS
    Studies on product switching have taken some important steps since Mori and Goto (2003) proposed a new model to help managers to decide product switching actions in a market where the product has a short lifecycle. The present study, assuming firms are in a duopolistic market with uncertainty, attempts to shed new light on this field. That is, utilizing the optimal stopping theory, a firm's product switching strategy for a duopolistic market is formulated and the property of the optimal timing for switching product is examined. Specifically, consideration is given to preventing imitations and the competitive advantages of the product. Our analysis reveals that the harder it is to imitate a product and the larger the competitive advantage, the longer the product cycle.
    Download PDF (536K)
  • Type: Appendix
    2007 Volume 58 Issue 5 Pages App23-
    Published: December 15, 2007
    Released: November 01, 2017
    JOURNALS FREE ACCESS
    Download PDF (57K)
  • Type: Appendix
    2007 Volume 58 Issue 5 Pages App24-
    Published: December 15, 2007
    Released: November 01, 2017
    JOURNALS FREE ACCESS
    Download PDF (57K)
  • Type: Appendix
    2007 Volume 58 Issue 5 Pages App25-
    Published: December 15, 2007
    Released: November 01, 2017
    JOURNALS FREE ACCESS
    Download PDF (57K)
  • Type: Appendix
    2007 Volume 58 Issue 5 Pages App26-
    Published: December 15, 2007
    Released: November 01, 2017
    JOURNALS FREE ACCESS
    Download PDF (57K)
feedback
Top