• Title/Summary/Keyword: N-Policy

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An Analysis of M/G/1 System with N and T-Policy (N-정책과 T-정책이 적용되는 M/G/1 시스템의 분석)

  • Hur, Sun;Lee, Hun-Gyu;Kim, Jong-Soo
    • Journal of Korean Institute of Industrial Engineers
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    • v.26 no.2
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    • pp.81-87
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    • 2000
  • As for M/G/1 queueing system, we use various control policies, with which we can optimize the system. Up to now the most widely adopted policies are N-Policy, T-Policy, D-Policy, and so on. The existing researches are largely concerned to find an optimal operation condition or to optimize the system under single policy in M/G/1 system. There are, however, few literatures dealing with multiple control policies at once to enhance the flexibility of the model. In this study, we consider M/G/1 system adopting N-Policy and T-Policy simultaneously. If one of two conditions is satisfied, then, the server starts the service. We call this Min(N,T)-Policy. We find the probability distribution of the number of customers and mean waiting time in steady state and derive a cost function. Next, we seek the $N^*$, optimal threshold under various N values. Finally, we reveal the characteristics of cost function.

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Analysis of a Maintenance·Repair Service Center Model Operating under Alternating Complementary Dyadic Policies (상호보완적인 이변수 운영정책이 교대로 적용되는 정비서비스센터 모형분석)

  • Rhee, Hahn-Kyou
    • Journal of Applied Reliability
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    • v.17 no.1
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    • pp.58-65
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    • 2017
  • Different from general operating policies applied for various waiting line situations, two complementary dyadic operating policies are applied alternatingly to a single server maintenance service center model. That is, either of the two dyadic Min (N, T) or Max (N, T) policy is applied to operate such center first and the other operating policy should be applied later, and then the same sequence of both operating policies is followed repeatedly. This operating policy is denoted by the Minimax (N, T) policy. Purpose: Because of the newly introduced operating policy, important system characteristics of the considered service center model such as the expected busy and idle periods, the expected number of customers in the service center and so on should be derived to provide necessary information for determination of the optimal operating policy. Methods: Based on concepts of the newly introduced Minimax (N, T) policy, all necessary system characteristics should be redefined and then derived by constructing appropriate relations between complementary two dyadic operating policies. Results: Desired system characteristics are obtained successfully using simple procedures developed by utilizing peculiar structure of the Minimax (N, T) policy. Conclusion: Applying Minimax (N, T) operating policy is equivalent to applying the simple N and T operating policies alternatingly.

A TRIAL SOLUTION APPROACH TO THE GI/M/1 QUEUE WITH N-POLICY AND EXPONENTIAL VACATIONS

  • Chae, Kyung-Chul;Lee, Sang-Min;Kim, Nam-Ki;Kim, Jin-Dong;Lee, Ho-Woo
    • Journal of the Korean Statistical Society
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    • v.33 no.3
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    • pp.283-298
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    • 2004
  • We present a trial solution approach to GI/M/l queues with generalized vacations. Specific types of generalized vacations we consider are N -policy and a combination of N-policy and exponential multiple vacations. Discussions about how to find trial solutions are given.

N-POILCY FOR (s,S) PERISHABLE INVENTORY SYSTEM WITH POSITIVE LEAD TIME

  • Krishnamoorthy, A.;Raju, N.
    • Journal of applied mathematics & informatics
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    • v.5 no.1
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    • pp.253-261
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    • 1998
  • (s,S) inventrory system of a perishable item with positive lead times and finite backlogs under N-policy Under this policy as and when the inventory level drops to s-N during a lead time local purchase is made. Three models are con-sidered. The limiting distribution on the inventory level is obtained and an associated cost analysis is made. Results ae numerically illustrated.

Subjectivity about Policy of Dental Treatment (치과진료 정책에 관한 주관성 연구 -치과 관련 전공자 중심으로-)

  • Lee, Jei-Young;Jeong, Mi-Ae
    • The Journal of the Korea Contents Association
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    • v.12 no.1
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    • pp.386-399
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    • 2012
  • This study was carried out by practical method in a subjectivity study accessible in-depth, in sloughing off old habit of functional quantity analysis about policy of dental treatment. The perception pattern come out in this study were divided into four types in Q-methodology. The result is as follows ; it is divided into 1[(N=11) : Extension Policy Type], 2[(N=13) : Institutional Improvement Type], 3[(N=5) : Image Improvement Type], 4[(N=14) : Treatment Focus Type], 5[(N=5) : Efficient Access Type], 6[(N=10) : Developmental Demand Type]. There are four types of fire fighter images. In conclusion, this study is to ascertain acceptance behavior about Reception Type on policy of dental treatment ; to offer a developmental suggestion about it.

Derivations of Upper and Lower Bounds of the Expected Busy Periods for a Controllable M/G/1 Queueing Model Operating Under the Triadic Max(N, T, D) Policy (삼변수 Max(N, T, D) 운용방침이 적용되는 조정가능한 M/G/1 대기모형의 busy period 기대값의 상한과 하한 유도)

  • Rhee, Hahn-Kyou
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.34 no.1
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    • pp.67-73
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    • 2011
  • Using the known result of the expected busy period for a controllable M/G/1 queueing model operating under the triadic Max (N, T, D) policy, its upper and lower bounds are derived to approximate its corresponding actual value. Both bounds are represented in terms of the expected busy periods for the dyadic Min (N, T), Min (N, D) and Min (T, D) and simple N, T and D operating policies. All three input variables N, T and D are equally contributed to construct such bounds for better estimation.

Analysis of the Push-Pull Queueing System under the N-Policy (N-정책을 갖는 Push-Pull 대기행렬 시스템의 분석)

  • Kim, Soo Yeon;Kim, Nam Ki;Kim, Jin Dong;Lee, Sang Min;Chae, Kyung Chul
    • Journal of Korean Institute of Industrial Engineers
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    • v.31 no.4
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    • pp.297-302
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    • 2005
  • Kopzon and Weiss adopted the notion of push-pull into the queueing system recently. We extend this queueing system to the ($N_1,N_2$)-policy version such that the original system corresponds to the special case $N_1=N_2=1$. For the extended system, we perform the cycle analysis and obtain the PGF of the stationary number of customers in the system.

Derivations of Upper and Lower Bounds of the Expected Busy Periods for the Triadic Min(N, T, D) Operating Policy applied to a Controllable M/G/1 Queueing Model (조정가능한 M/G/1 대기모형에 삼변수 Min(N, T, D) 운용방침이 적용될 때 busy period 기댓값의 상한과 하한 유도)

  • Rhee, Hahn-Kyou
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.33 no.2
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    • pp.97-104
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    • 2010
  • Using the known result of the expected busy period for the triadic Min (N, T, D) operating policy applied to a controllable M/G/1 queueing model, its upper and lower bounds are derived to approximate its corresponding actual value. Both bounds are represented in terms of the expected busy periods for the dyadic Min (N, T), Min (N, D) and Min (T, D) and simple N, T and D operating policies. All three input variables N, T and D are equally contributed to construct such bounds for better approximations.

A System Analysis of a Controllable Queueing Model Operating under the {T:Min(T,N)} Policy (조정가능한 대기모형에 {T:Min(T,N)} 운용방침이 적용되었을 때의 시스템분석)

  • Rhee, Hahn-Kyou
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.38 no.1
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    • pp.21-29
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    • 2015
  • A steady-state controllable M/G/1 queueing model operating under the {T:Min(T,N)} policy is considered where the {T:Min(T,N)} policy is defined as the next busy period will be initiated either after T time units elapsed from the end of the previous busy period if at least one customer arrives at the system during that time period, or after T time units elapsed without a customer' arrival, the time instant when Nth customer arrives at the system or T time units elapsed with at least one customer arrives at the system whichever comes first. After deriving the necessary system characteristics including the expected number of customers in the system, the expected length of busy period and so on, the total expected cost function per unit time for the system operation is constructed to determine the optimal operating policy. To do so, the cost elements associated with such system characteristics including the customers' waiting cost in the system and the server's removal and activating cost are defined. Then, procedures to determine the optimal values of the decision variables included in the operating policy are provided based on minimizing the total expected cost function per unit time to operate the queueing system under considerations.

A Stochastic Model for Maximizing the Lifetime of Wireless Sensor Networks (확률모형을 이용한 무선센서망 수명 최대화에 관한 분석)

  • Lee, Doo-Ho;Yang, Won-Seok
    • Journal of the Korean Operations Research and Management Science Society
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    • v.37 no.3
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    • pp.69-78
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    • 2012
  • Reduction of power consumption has been a major issue and an interesting challenge to maximize the lifetime of wireless sensor networks. We investigate the practical meaning of N-policy in queues as a power saving technique in a WSN. We consider the N-policy of a finite M/M/1 queue. We formulate the optimization problem of power consumption considering the packet loss probability. We analyze the trade-off between power consumption and the packet loss probability and demonstrate the operational characteristics of N-policy as a power saving technique in a WSN with various numerical examples.