Journal of the Operations Research Society of Japan

[title in Japanese]

Article type: Cover
1983 Volume 26 Issue 1 Pages Cover1-
Published: 1983
Released on J-STAGE: June 27, 2017

DOIhttps://doi.org/10.15807/jorsj.26.Cover1

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[title in Japanese]

Article type: Appendix
1983 Volume 26 Issue 1 Pages App1-
Published: 1983
Released on J-STAGE: June 27, 2017

DOIhttps://doi.org/10.15807/jorsj.26.App1

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OPTIMUM INSPECTION POLICY FOR A PROTECTIVE DEVICE

Etsuro SHIMA, Toshio NAKAGAWA, Yoshiya SAWA

Article type: Article
1983 Volume 26 Issue 1 Pages 1-11
Published: 1983
Released on J-STAGE: June 27, 2017

DOIhttps://doi.org/10.15807/jorsj.26.1

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Almost all systems install a protective device to prevent shocks which occur suddenly from outside or inside. A typical example is transformers with a surge absorber and computer systems with a C.V.C.F. device. It is extremely serious If the device has failed when a shock occurs. To avoid such an unfavourable situation, we need to check whether the device is good or not. This paper considers a system with the device which fails by shock or by myself. The device has a failure time distribution F(t), and shocks occur o;t randomly in time, i.e., according to an exponential distribution (1 - e^<-αt> ) . If the device is good, then it prevents shocks with probability 1 - p, other-wise a system becomes failure by any shock. We inspect the device at periodic times kl (k = 1, 2, ...) under these assumptions. Costs c_l and c_2 are suffered for failures of both system and device and of only device, respectively, and c_3 is for one inspection. Then, using the usual calculus method of probability, the expected cost rate is [numerical formula] where F^^- ≡ 1 - F. It is difficult to compute an optimum inspection time l* which minimizes C(l;p) . In particular case of F(t) = I - e^<-λt>, we discuss an optimum inspection policy for 0 ≦ p ≦ I . We finally show figures which give an optimum time l* and its effect [C(∞;p) - C(l*;p)]/C(∞;p), for two cases where the mean failure time (1/λ) of the device and the mean interval (1/α) of shocks are changed.

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ALGORITHMIC METHODS FOR PH/PH/1 QUEUES WITH BATCH ARRIVALS OR SERVICES

Yutaka Baba

Article type: Article
1983 Volume 26 Issue 1 Pages 12-32
Published: 1983
Released on J-STAGE: June 27, 2017

DOIhttps://doi.org/10.15807/jorsj.26.12

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We discuss algorithms for the computation of the steady state features of PH/PH/1 queues with bounded batch arrivals or batch services. Many characteristic quantities such as the mean and variance of queue length in continuous time, the mean waiting time, the waiting probability, etc. are obtained in computationally tractable forms. We also show various numerical values.

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AN ALGORITHMIC SOLUTION TO THE M/PH/c QUEUE WITH BATCH ARRIVALS

Yutaka Baba

Article type: Article
1983 Volume 26 Issue 1 Pages 33-50
Published: 1983
Released on J-STAGE: June 27, 2017

DOIhttps://doi.org/10.15807/jorsj.26.33

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This paper discusses algorithms for deriving the steady state features of the M/PH/c queue with batch arrivals. Many characteristic quantities such as the mean and variance of queue length in continuous time, the mean waiting time, the waiting probability, etc. are obtained in computationally tractable form. Numerical examples show that the effects of changing various parameters of queueing model may be examined at a small computational cost.

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AN APPLICATION OF THE LUMPING METHOD TO A LOSS SYSTEM WITH TWO TYPES OF CUSTOMERS

Tsukasa Sato, Masao Mori

Article type: Article
1983 Volume 26 Issue 1 Pages 51-60
Published: 1983
Released on J-STAGE: June 27, 2017

DOIhttps://doi.org/10.15807/jorsj.26.51

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This paper applies the lumping method, proposed by Takahashi [4], to get stationary probabilities numerically for a loss system with two types of input streams. By using the method we can evaluate numerically the effect of introducing several servers who are capable to serve both types of customers.

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ON THE PRACTICAL EFFICIENCY OF VARIOUS MAXIMUM FLOW ALGORITHMS

Hiroshi Imai

Article type: Article
1983 Volume 26 Issue 1 Pages 61-83
Published: 1983
Released on J-STAGE: June 27, 2017

DOIhttps://doi.org/10.15807/jorsj.26.61

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We investigate the practical efficiency of various maximum flow algorithms by a great number of systematically-designed computational experiments, where we develop and summarize the techniques useful for solving the problem in practice. The methods implemented are depth-first search, breadth-first search, Dinic's, Karzanov's, three Indians' and Galil and Naamad's. We conclude that, among the implemented methods, Dinic's method and Karzanov's are the most efficient. In these two methods, Dinic's method is so simple that we can code it quite easily, and takes rather small memory storages. Karzanov's method is superior from the viewpoint of the complexity in the worst case.

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[title in Japanese]

Article type: Appendix
1983 Volume 26 Issue 1 Pages App2-
Published: 1983
Released on J-STAGE: June 27, 2017

DOIhttps://doi.org/10.15807/jorsj.26.App2

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[title in Japanese]

Article type: Cover
1983 Volume 26 Issue 1 Pages Cover2-
Published: 1983
Released on J-STAGE: June 27, 2017

DOIhttps://doi.org/10.15807/jorsj.26.Cover2

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[title in Japanese]

Article type: Cover
1983 Volume 26 Issue 1 Pages Cover3-
Published: 1983
Released on J-STAGE: June 27, 2017

DOIhttps://doi.org/10.15807/jorsj.26.Cover3

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