Journal of Japan Industrial Management Association
Online ISSN : 2187-9079
Print ISSN : 1342-2618
ISSN-L : 1342-2618
Volume 52 , Issue 4
Showing 1-13 articles out of 13 articles from the selected issue
  • Type: Cover
    2001 Volume 52 Issue 4 Pages Cover7-
    Published: October 15, 2001
    Released: November 01, 2017
    JOURNALS FREE ACCESS
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  • Type: Cover
    2001 Volume 52 Issue 4 Pages Cover8-
    Published: October 15, 2001
    Released: November 01, 2017
    JOURNALS FREE ACCESS
    Download PDF (37K)
  • Type: Index
    2001 Volume 52 Issue 4 Pages Toc4-
    Published: October 15, 2001
    Released: November 01, 2017
    JOURNALS FREE ACCESS
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  • Saburo TENDA, Tatsuo MATSUTOMI, Eiichi TSUDA
    Type: Article
    2001 Volume 52 Issue 4 Pages 191-201
    Published: October 15, 2001
    Released: November 01, 2017
    JOURNALS FREE ACCESS
    A method for designing large scale flexible mixed-product lines is presented. The word"flexible" means product-mix flexibility. The flexible mixed-product line executes various production plans. Each production plan represents the quantity scheduled each product type to assemble in a time period. Our design method consists of a branch and bound method for solving small scale subproblems constructed by decomposing a large scale design problem and a procedure for decomposing the large scale problem. This method searches out a solution of the design problem by assigning tasks (elemental works) to each workstation and selecting one subject (worker, robot, equipment or a complex of those) and the kinds of tools to perform the tasks assigned to each workstation. This design method requires the following data and information. (1)The product types to be assembled on the same line. (2)The various production plans to be executed. (3)The precedence diagram of each product type and the combined precedence diagram. Kinds of subjects and kinds of tools able to perform each task and performance times are written in the diagram. The combination of the subject and the tool able to perform a task determines the task performance time. This design method adopts the goal of minimizing the number of workstations to execute each production plan within a time period. The validity of this method was confirmed by solving problems. The solutions were mainly assessed by the following criteria. (1)Whether the number of workstations on the line that is designed by this method is minimum or not. (2)Whether designing by this method is fast work or not. This method is effective in solving the large scale problem that the other methods can not search out the optimum solution in a short time.
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  • Mitsugu SAWA, Hiroshi UGAJIN, Takao OHKUBO, Shigeru HAGA
    Type: Article
    2001 Volume 52 Issue 4 Pages 202-210
    Published: October 15, 2001
    Released: November 01, 2017
    JOURNALS FREE ACCESS
    This study aims at developing a new subjective assessment index by simply evaluating the effect of work duration on the worker's psycho-physiological state. The method of this study was to examine how the effects of continuous work sessions for 100, 200 and 400 minutes on workers were reflected in the results of a new questionnaire prepared based on multitask tests using a simplified train operation simulator. The test task was the operation for a total of five times, nine times and 17 times at a cycle/route of 23 minutes per cycle (including the measurement time of three minutes) following a timetable. The subjects were total of 19 male university students aged 20-24. As a result, it was found that subjective symptoms that develop during the work can be evaluated from three different factors. The factors are 1) drowsiness and fatigue, 2) effort to overcome strain and 3) weariness and difficulty of concentration. To evaluate the accumulated work strain that develops during the work, it is effective to evaluate the drowsiness and fatigue or weariness and difficulty of concentration. To evaluate the attention and effort to cope with the work stress, the effort to overcome strain is an effective measure. Based on this result, a new subjective assessment index has been developed with two items representing each of the three factors, which is easily applicabl to field surveys.
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  • Katsumi MORIKAWA, Nobuto NAKAMURA
    Type: Article
    2001 Volume 52 Issue 4 Pages 211-220
    Published: October 15, 2001
    Released: November 01, 2017
    JOURNALS FREE ACCESS
    Many researchers have proposed effective makespan minimization methods for deterministic job shops. In actual production environments, however, the assumed and actual processing times of an operation are not necessarily the same. Therefore we must take into account the possible change of processing times even if the scheduling problem is defined by deterministic processing times. In this study we try to obtain a makespan minimum schedule which is less sensitive to the uncertainty of processing times. As the job shop scheduling problem has, in general, many minimum makespan schedules, we have proposed a secondary criterion called instability which is defined as the maximum number of operations of which start time is delayed when the completion time of an operation is delayed by one time unit. The minimum instability schdule is theoretically insensitive only for the one time unit of completion delay in any one operation, and thus, it is not clear that our secondary criterion is reasonable under the conditions such that the delay of completion is more than one time unit, or two or more operations are delayed. For the given length of completion delay, a modified graph based on the disjunctive graph is introduced to obtain the maximum number of operations of which start time will be delayed. By overlapping the modified graphs, the effect of completion delay in two or more operations can be calculated. For fifteen test problems of which the size was 50 or 60 operations, we have compared the effect of the length of completion delay and the number of operations delayed between the minimum and maximum instability schedules. The results show that the minimum instability schedule is genrally insensitive to the uncertainty of processing times when a relatively shorter completion delay will occur in a small number of operations.
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  • Tomotaka ICHIMURA, Hitoshi TSUBONE
    Type: Article
    2001 Volume 52 Issue 4 Pages 221-230
    Published: October 15, 2001
    Released: November 01, 2017
    JOURNALS FREE ACCESS
    In this paper the issue of designing an efficient production system by increasing several types of flexibility is examined. Increasing manufacturing flexibility is a key strategy for efficiently improving market responsiveness in the face of uncertain market demand for final products. The manufacturing system consists of multiple plants, of which individual plants have multiple manufacturing lines which are designed to produce limited types of products in accordance with their size, materials, etc. Imbalance in the workload occurs among plants as well as amog manufacturing lines due to the fluctuations in market demand for final products, thus resulting in idleness of some manufacturing lines and longer lead time in some manufacturing lines due to the high workload. Three types of manufacturing flexibility are considered because they are interrelated : machine flexibility, routing flexibility and process flexibility. Machine flexibility refers to the various types of operations that a machine can perform without requiring the prohibitive effort of switching from one order to another. Routing flexibility is the capability of processing a given set of part types using more than one line(alternative line) in the plant. Process flexibility results from being able to build different types of final products at the same plant. First, we clarify how these types of flexibility affect the manufacturing performance by improving only one type of flexibility or by improving multiple types of flexibility simultaneously. The average lead time and the imbalance in workload are adopted as measures of the manufacturing performance. Second, from these results, we can show some numerical example of relationships between the index values of these flexibility types which can satisfy the expected criteria, if management can provide them.
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  • Kenichi FUNAKI, Kazuho YOSHIMOTO
    Type: Article
    2001 Volume 52 Issue 4 Pages 231-238
    Published: October 15, 2001
    Released: November 01, 2017
    JOURNALS FREE ACCESS
    We propose a periodic preventive maintenance policy for a repairable system assuring a required interval availability. Required interval availability is the fraction of total operating time over a given time interval which is required to accomplish some task by the system. Under the proposed policy, the preventive maintenance interval is determined to minimize the total expected cost per unit time assuring the required interval availability with a given confidence probability. In this paper, we formulate the policy when minimal repair is performed upon failure and derive a condition for existence of the optimal solution. Further we provide a graphical method which is useful when one must analyze the sensitivity of the optimal solution with regard to change of maintenance and minimal repair costs. Some numerical examples are presented in order to illustrate typical results of the policy when time to failure is Weibull distributed and time to repair is gamma distributed, respectively.
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  • Hirofumi KAMEKAWA, Masanobu MATSUMARU
    Type: Article
    2001 Volume 52 Issue 4 Pages 239-255
    Published: October 15, 2001
    Released: November 01, 2017
    JOURNALS FREE ACCESS
    The paper analyzes economic time series data with involved and irregular fluctuations. The daily data employed are the YEN rates against the USD in the foreign exchange markets. In this study, we propose the necessity of dynamic chaos analysis technique against static chaos analysis in previous studies and prove the validity of our technique by an empirical study. To clarify the proposal, the paper analyzes the relationship between economic time series chaos and prediction precision by chaotic time series models, and suggests a technique by which the reliability of prediction precision can be evaluated. It becomes decidedly clear from the empirical study that the domain of time series of the YEN-USD rates consists of two domains. One is the domain that showed the presence of chaos. The other is the domain that doesn't show it. Accordingly analysis of real world data indicates if judgment is based on static chaos analysis, in the previous studies, the forecasting will carry a risk. In this study, we propose both a probability evaluation method and a deterministic evaluation method, and the results of the empirical studies indicate that these methods have a high evaluation power.
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  • Type: Appendix
    2001 Volume 52 Issue 4 Pages 256-
    Published: October 15, 2001
    Released: November 01, 2017
    JOURNALS FREE ACCESS
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  • [in Japanese], [in Japanese]
    Type: Article
    2001 Volume 52 Issue 4 Pages 257-258
    Published: October 15, 2001
    Released: November 01, 2017
    JOURNALS FREE ACCESS
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  • [in Japanese], [in Japanese], [in Japanese]
    Type: Article
    2001 Volume 52 Issue 4 Pages 259-262
    Published: October 15, 2001
    Released: November 01, 2017
    JOURNALS FREE ACCESS
    Download PDF (383K)
  • Type: Appendix
    2001 Volume 52 Issue 4 Pages App4-
    Published: October 15, 2001
    Released: November 01, 2017
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    Download PDF (67K)
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