Journal of Japan Industrial Management Association
Online ISSN : 2187-9079
Print ISSN : 1342-2618
ISSN-L : 1342-2618
Volume 68 , Issue 1
Showing 1-5 articles out of 5 articles from the selected issue
Original Paper (Theory and Methodology)
  • Manabu KUROKI, Haruka YAMASHITA
    2017 Volume 68 Issue 1 Pages 1-12
    Published: April 15, 2017
    Released: May 15, 2017
    JOURNALS FREE ACCESS

    This paper proposes an improved k-planes clustering method to classify a p-dimensional data-set into k subsets that are characterized by k different qj dimensional linear structures (0 ≤ qjp - 1; j = 1, ..., k). The proposed method can be identified with the k-means clustering method when all k subsets can be characterized by the 0 dimensional linear structures, and with the k-planes clustering method when they can be characterized by the same q dimensional linear structures (0 ≤ qp - 1). In addition, the proposed method is more flexible than those proposed by Bezdek et al. (1981a, 1981b), Bradley and Mangasarian (2000) and Kuroki et al. (2004), in the sense that the same dimensional linear structures for some of k data-sets can be introduced if necessary. Furthermore, letting q = max{qj |j = 1, , ..., k}, we provide a procedure for constructing the p - q dimensional visual hyperplane to visualize the analytical results using the improved k- planes clustering method. Finally, through numerical experiments and a case study, we show that the performance of the improved k- planes clustering method is superior to those of the k-means method and the k-planes method.

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  • Kenji HIRANO
    2017 Volume 68 Issue 1 Pages 13-22
    Published: April 15, 2017
    Released: May 15, 2017
    JOURNALS FREE ACCESS

    This study proposes a method of visualizing and analyzing arguments based on the emotional aspects that are discussed during the decision-making process of business in order to determine problems that exist and the causes of failure in the planning process. When difficulties regarding business change occur, they result in emotional opinions being expressed during business meetings. These opinions are useful in identifying difficult situations as well as conflicting view-points that exist between stakeholders. By tracking emotional responses through the decision-making process, it is possible to identify the essential points of success or failure of a business transformation. This paper establishes emotional attributes for analyzing business discussions by arranging aspects of arguments in business meetings. Next, quantification method Type-3 is used to visualize the structure of discussions in terms of categorized aspects of arguments that include emotional attributes expressed by emoticon. This way it is easy to recognize conflicting opinions and the point of breakdown in business meetings, and then steps are taken to resolve the issues. This method also examines some examples that are accumulated in the business system transformation model (BSTM) that proves useful. Finally, operational problems and possibilities of this method are discussed.

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  • Liqun HUANG, Tomoya SHIMIZU, Hiroaki MATSUKAWA
    2017 Volume 68 Issue 1 Pages 23-32
    Published: April 15, 2017
    Released: May 15, 2017
    JOURNALS FREE ACCESS

    This paper considers a supply contract in a two-stage supply chain consisting of one supplier and one buyer. Market demand is stochastic, and there are two opportunities for demand forecasts. With the first forecast at the beginning of production, the buyer puts a firm fixed order Q to the supplier, purchasing a quantity qo of options at the same time. With the second forecast at the beginning of the sales season, the buyer determines execution quantity qe of the option within the purchased quantity of options (qeqo). The supplier determines option price po and option execution price pe, while the buyer determines Q, qo, qe under the given po and pe. Both buyer and supplier try to maximize their own profit; however, the buyer's decision variables Q, qo, qe are dependent on the supplier's decision variables po and pe. The purpose of this research is to determine the optimal po and pe for the supplier. The solution process is two-fold. In the first step, we solve the buyer's optimization problem to determine optimal Q, qo and qe, which can maximize the buyer's profit. The optimal order quantity Q, option quantity qo and execution quantity qe are functions of po and pe. Therefore, in the second step, we solve the supplier's optimization problem to determine the optimal po and pe so as to maximize the supplier's profit. We construct the supplier's profit model and derive an analytical function to determine the optimal option price po and option execution price pe. Since the analytical function consists of seven order implicit system equations, we apply a numerical solution procedure using Mathematica instead of deriving the closed analytical form of po and pe. Through numerical experiments, we show that the optimal option price po and option execution price pe always provide maximum profit to the supplier, while the buyer keeps maximum profit at the same time.

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  • Kentaro HAYASHI, Takashi IROHARA, Yoshihito SASAKI
    2017 Volume 68 Issue 1 Pages 33-46
    Published: April 15, 2017
    Released: May 15, 2017
    JOURNALS FREE ACCESS

    In most distribution centers, order picking is the most labor-intensive and costly activity. Therefore, improving the productivity of order picking system can reduce the order-receiving lead time and lower cost. There are many studies about order picking, however they consider only one picking system; for example, picking items in each zone, picking items by order batch and so on. In this paper, we propose an order picking system in which two picking systems are combined. One picking system is called “multi-pick” which is one of the most popular picking systems and the other picking system is called “category-pick” which is introduced in this paper. Multi-pick is a picking system that picks by order batch, and category-pick is a picking system that picks by item type. We propose an order picking system by adding multi-pick to category-pick. Items are divided into two groups: picked by multi-pick and picked by category-pick; that is, item classification based on customer demand. In multi-pick, we consider the similarity between orders, and in category-pick, we consider customer demand, which is order frequency. In the order picking system we propose, there are three types of order. The first type is picked by only multi-pick. The second type is picked by only category-pick. The last type is picked using both multi-pick and category-pick. We conducted a numerical experiment using some item classification patterns. The experimental results show that combining the two picking systems makes total working time shorter than that of only one picking system.

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Original Paper (Case Study)
  • Seiko TAKI, Ryosuke KAKUTA, Masato TAKANOKURA, Tetsuo YAMADA
    2017 Volume 68 Issue 1 Pages 47-55
    Published: April 15, 2017
    Released: May 15, 2017
    JOURNALS FREE ACCESS

    In the 1950s, Lillian M. Gilbreth et al. carried out research focusing on issues concerning child care in domestic work in order to facilitate improvements in child care. However, in present-day Japan, support for female child care providers is still lacking and there remain problems to be solved. Therefore, in this study, we acquired and analyzed the six-month life logs of mothers raising infants in Japan. We examine the mothers' actions, extent of activity and physically demanding actions (actions requiring much physical effort) in child care, which change according to the monthly age of the child. In addition, a detailed analysis of “outings” among high-intensity activities during childcare was performed.

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