Journal of Japan Industrial Management Association
Online ISSN : 2187-9079
Print ISSN : 1342-2618
ISSN-L : 1342-2618
Volume 57 , Issue 1
Showing 1-17 articles out of 17 articles from the selected issue
  • Type: Cover
    2006 Volume 57 Issue 1 Pages Cover1-
    Published: April 15, 2006
    Released: November 01, 2017
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  • Type: Cover
    2006 Volume 57 Issue 1 Pages Cover2-
    Published: April 15, 2006
    Released: November 01, 2017
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  • Type: Index
    2006 Volume 57 Issue 1 Pages Toc1-
    Published: April 15, 2006
    Released: November 01, 2017
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  • Yasuhiko Murase, Shiro Masuda, Shuichi Fukuda
    Type: Article
    2006 Volume 57 Issue 1 Pages 1-9
    Published: April 15, 2006
    Released: November 01, 2017
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    Conveyer production systems aiming at mass production were widely used during the high-growth era. In recent years, as a next-generation production system, cellular manufacturing systems are anticipated and many case studies have been reported, but little attention has been paid to the mathematical model for cellular manufacturing systems. Basically, the cellular manufacturing system is a method that brings individuals into focus. Although operator skill is an important factor when two systems are compared, in the previous paper, the work element times were only applied as a random variable for stochastic assembly line balancing. Therefore, in this paper, the mechanism of the improvement in the productivity of the conveyer production system and the cellular manufacturing system are studied by a newly proposed mathematical model introduced from the inventory theory. The main features of the model are as follows. The Ordering Point model in the inventory theory is applied by replacing "Lead Time and Ordering Point" with "work period and required man-hours", respectively. Then, the work element times and operator skills can be dealt with as random variables by applying the "deviation of the sum of random variables" and "random sum". Moreover, since productivity is affected by the amount of work for the operator, we rectify the influence by deriving an operator service factor based on the theorem of the memorization of amount of information such as the Magical Number Seven and USAF examination. Furthermore, the validity of the proposed models are examined through numerical simulations compared with a case study.
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  • Masanori Horio, Atsuo Suzuki
    Type: Article
    2006 Volume 57 Issue 1 Pages 10-22
    Published: April 15, 2006
    Released: November 01, 2017
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    RCPSP/τ (Resource-Constrained Project Scheduling Problem with Time-dependent resource parameters) is one of the most useful variations of RCPSP, which was named by Hartmann. In RCPSP/τ, resource consumption and available resources change depending on time. Since scheduling conditions are extended, RCPSP/τ can deal with many more types of scheduling problems than RCPSP. On the other hand, RCPSP/τ is more complicated than standard scheduling problems. It is difficult to obtain optimal solutions for large-scale RCPSP/τ. Actually, it is proved to be NP-hard. We have proposed a new method for solving the problems effectively, and developed a general project scheduler which had a framework of RCPSP/τ using the method. The scheduler has been applied to many types of problems, such as PSPLIB, school time-table generation problems, and nurse scheduling problems. The scheduler needs a new quantitative evaluation method to measure its abilities. In this research, we created new benchmark problems for RCPSP/τ, because there are no appropriate benchmark problems for RCPSP/τ even in PSPLIB. Using the problems, we evaluated quantitatively the ability of the scheduler. We compared the solutions of our scheduler with the optimal solutions obtained using general optimization software (Xpress-MP). As a result, our scheduler obtained good approximate solutions to almost all problems within reasonable CPU time.
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  • Hisashi YAMAMOTO, Masayuki MATUI, Jun LIU
    Type: Article
    2006 Volume 57 Issue 1 Pages 23-31
    Published: April 15, 2006
    Released: November 01, 2017
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    We consider the following situation. There exists an object with some constraints (e.g., processing time with a target), these constraints produce a risk and the object occurs repeatedly for multiple periods. In this paper, the problem of minimizing the expected risk in such a situation called a "limit-cycle problem with multiple periods", and we consider how to resolve it. First, we classify the limit-cycle problem with multiple periods into some classes and propose, as this type of problem, "a limit-cycle problem with dependent multiple periods", in which the occurrence of an object in a period depends on the occurrences of other objects in the other periods. Next, we propose a mathematical model for the limit-cycle problem with dependent multiple periods, and an efficient algorithm for expected risk (cost) is obtained by using some constraints. Finally, we conduct some numerical experiments to research the optimal assignments aimed at the minimum expected risk. Our proposed algorithm is based on recursive formulas, and the order of computing time is polynomial for the number of periods. From the results of the numerical experiments, it is found out that there exists a similar property to the "Bowl phenomenon" in a series manufacturing line, with simple assumptions. The results obtained in this paper are useful for the design of a production seat system.
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  • Shin'ichi YOSHIKAWA, Masatoshi TANAKA, Yoshio TABATA
    Type: Article
    2006 Volume 57 Issue 1 Pages 32-38
    Published: April 15, 2006
    Released: November 01, 2017
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    Inventory management has a significant impact on the costs and profitability of an organization. The economic order quantity (EOQ) model is still widely used to guide the management of inventories in many industiral enterprises and service organizations. EOQ captures the trade-off between inventory carrying cost and ordering cost for a single item. In practice, however, it is very difficult to identify the relevant ordering cost for each item with accuracy. When the parameters of each item are known, the optimal policy can be applied easily. But, in general, it cannot be adopted easily because the parameters are unknown. In the past, the method for minimizing the order frequencies of a group of items with unknown cost parameters in the EOQ model was reported by Kailash et al. However, their proposed method gives the order frequencies as positive real numbers. In actual inventory problems, it is desirable that item order frequencies are obtained as discrete integers. In our model, we propose a practical method where the order frequency is a positive integer. Here, we emphasize treating two kinds of problems. One is the method of minimizing the inventory carrying costs subject to the given total of order frequency. The main problem is to develop a method for minimizing the total of all orders subject to restricted inventory carrying costs. First of all, we investigate the formulation of the problems and a solution algorithm. Additionally, we show the numerical examples to illustrate and prove our proposed methods.
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  • Takuya Yamada, Takashi Irohara
    Type: Article
    2006 Volume 57 Issue 1 Pages 39-50
    Published: April 15, 2006
    Released: November 01, 2017
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    It is generally known that the facility layout problem (FLP) is to find an optimal layout with respect to the minimization of material handling costs (MHC) between departments. In most studies on FLP, the existence of aisles and I/O locations in each department are ignored. While there are some layout techniques that consider the aisle structure and I/O location, they have many problems. There are not any techniques that consider the I/O type of a department. Additionally in most studies, the FLP is modeled as a combinatorial optimization problem. When solving a FLP model, only the relative location of departments, aisles and I/O can be decided, not a detailed layout. In this paper, a new layout design methodology is proposed, in which a detailed layout including the aisle structure and I/O locations of departments can be decided using the hybrid approach of combinatorial optimization and mathematical programming approaches. In addition, a new layout expression is proposed based on a revised location matrix that enables one to consider not only the guillotine-cut type layout but also the spiral type layout. The proposed algorithm is based on Simulated Annealing combined with some local search. The objective function is the minimization of materials handling cost between the I/O points of departments along the aisle with the shortest distance. The results of computational experiments show the effectiveness of the proposed algorithm.
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  • Yasuhiko TAKEMOTO, Ikuo ARIZONO
    Type: Article
    2006 Volume 57 Issue 1 Pages 51-58
    Published: April 15, 2006
    Released: November 01, 2017
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    The quality of a lot has sometimes been evaluated based on attribute properties such as the percentage of nonconforming items or the number of nonconforming items in the lot. On the other hand, Taguchi has proposed the concept of "quality loss" as the evaluation measure of quality of items based on variable properties. Concretely, Taguchi's loss function has been defined as a quadratic function based on the departure from the target value of an item. Recently, from the viewpoint of assuring the quality loss based on Taguchi's loss function, a single sampling inspection plan based on operating characteristics has been proposed. This sampling procedure has been designed for the purpose of assuring both the specified producer's risk for the lot with an acceptable quality loss limit and the consumer's risk for the lot with a rejectable quality loss limit. However, the disposition of the rejected lot isn't specifically declared in the sampling inspection plan mentioned above. While, there is a sampling inspection plan with screening by attribute in which the rejected lot in the sampling inspection is thoroughly inspected and nonconforming items are exchanged for conforming items or repaired. In this sampling procedure, the sampling plans have been designed for the purpose of assuring the percentage of nonconforming items in every lot and the upper limit of the average outgoing quality level as the average outgoing percentage of nonconforming items. In this article, the quality evaluation based on Taguchi's loss function is adopted instead of the quality evaluation based on the percentage of nonconforming items as lot quality. Then, we propose a single sampling inspection plan with screening by variable indexed by Taguchi's loss function for the purpose of assuring the upper limit of the maximum expected surplus loss.
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  • Yoshiaki ISHIHARA, Shusaku HIRAKI
    Type: Article
    2006 Volume 57 Issue 1 Pages 59-67
    Published: April 15, 2006
    Released: November 01, 2017
    JOURNALS FREE ACCESS
    This paper aims to propose the heuristics for a vehicle routing problem in a package reuse system. Recently, from the viewpoint of environmental protection, many manufacturers construct reuse and/or recycling systems for disposed products. With the operations of reuse and/or recycling systems, effective systems for reverse logistics where disposed products are collected from customers are needed. In this paper, a vehicle routing problem for a package reuse system is considered, where disposed packages are transported by filling the empty capacities of many vehicles traveling to pick-up destinations or returning to their points of origin. We formulate a vehicle routing model for a mathematical programming problem, which maximizes the total transportation quantity of disposed packages, propose a heuristics using the column generation method for solving a Lagrangian dual, and clarify the effectiveness of the proposed heuristics using some numerical examples.
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  • Hiroshi SAKAI, Yutaka WATANABE
    Type: Article
    2006 Volume 57 Issue 1 Pages 68-79
    Published: April 15, 2006
    Released: November 01, 2017
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    The globalization of economic activities and the development of IT in recent years are promoting the expansion of international, interactive transportation. Therefore, the concentration of cargo at container terminals continues, and the role of ports in distribution is becoming more important. On the other hand, contributing to reductions in environmental burden and establishing a sustainable society are important issues in the transportation field. In this paper, we propose a system model for estimating the carbon dioxide emission at a container terminal. It consists of a decision process to select the evaluation level of accuracy according to the availability of information and data needed to evaluate it, and sub-models for calculating the carbon dioxide emissions. Using this system model, the carbon dioxide emissions from sea transportation, land transportation and cargo handling within the port area can be evaluated on the micro level, hybrid level or macro level. The amounts of carbon dioxide emissions at container terminals of major ports in Japan were calculated applying this model. As a result, the validity and the adaptability of the proposed procedure were clarified. This system model is generally applicable for investigating carbon dioxide emissions when several kinds of transportation activities exist at the same time.
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  • Takashi Kawanami, Takakazu Ishimatu
    Type: Article
    2006 Volume 57 Issue 1 Pages 80-87
    Published: April 15, 2006
    Released: November 01, 2017
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    In this paper, a technique for evaluating productivity in a flow shop based on the in-process inventories generated by an unbalance workload is proposed. Using this technique, an efficient improvement strategy can be obtained. There are two kinds of waiting in the production process: the first one is "machining wait", which means the products in the previous process have to wait because the following machining process is busy; and the other one is "arrival wait", which means the workers await the arrival of the product from the previous process. In-process inventory is generated by "machining wait". In most production systems, these two kinds of waiting phenomena have fuzzy characteristics since they are indefinitely or intentionally determined depending on the workers' situations. Considering that the employment of a push system determines these waiting phenomena uniquely, we propose an efficient production process improvement technique. A feature of our technique is that stagnation time in the in-process inventories is introduced as an index to evaluate the efficiency of the production process. The proposed technique is achieved as follows. Firstly, the proposed technique calculates the stagnation time at each process. Secondly, the technique determines the processes that should be improved by priority. Once the improvement of a process is achieved, the same technique is applied to find the next process to be improved. An efficient production system can be designed by repeating these procedures. In order to apply this technique effectively, a program that calculates the stagnation time of the focused production process was developed. This program was used at several medium and small companies in Nagasaki and the productivity was remarkably improved.
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  • Type: Appendix
    2006 Volume 57 Issue 1 Pages App1-
    Published: April 15, 2006
    Released: November 01, 2017
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  • Type: Appendix
    2006 Volume 57 Issue 1 Pages App2-
    Published: April 15, 2006
    Released: November 01, 2017
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  • Type: Appendix
    2006 Volume 57 Issue 1 Pages App3-
    Published: April 15, 2006
    Released: November 01, 2017
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  • Type: Appendix
    2006 Volume 57 Issue 1 Pages App4-
    Published: April 15, 2006
    Released: November 01, 2017
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  • Type: Appendix
    2006 Volume 57 Issue 1 Pages App5-
    Published: April 15, 2006
    Released: November 01, 2017
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