• 제목/요약/키워드: Customer Waiting Cost

검색결과 23건 처리시간 0.023초

계층적(階層的) 네트웍 대기구조(待機構造)를 갖는 조직(組織)의 생산함수(生産函數)에 대한 연구(硏究) (A Production Function for the Organization with Hierarchical Network Queue Structure)

  • 강석현;김성인
    • 대한산업공학회지
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    • 제12권1호
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    • pp.63-71
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    • 1986
  • In the organization with a hierarchical network queue structure a production function is derived whose input factors are the numbers of servers at nodes and output is the number of served customers. Its useful properties are investigated. Using this production function, the contributions of servers to the number of served customers are studied. Also given an expected waiting time in the system for each customer, the optimal numbers of servers at nodes are obtained minimizing a cost function.

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휴가가 존재하는 M/M/2 대기 시스템의 한계치를 이용한 제어정책 (The Threshold Policy in the M/M/2 Queue with Server Vacation)

  • 이효성
    • 한국경영과학회지
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    • 제20권2호
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    • pp.1-10
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    • 1995
  • In this study, a threshold policy is considered for the M/M/2 queueing system with server vacations. The probability generating function for the number of customers present in the system is derived using an embedded Markov chain approach. Then, assuming a linear cost structure, an efficient procedure to find an optimal threshold policy is presented. The Laplace-Stieltjes transofrm for th waiting time of an arbitrary customer under a "FIFO" discipline is also derived.o derived.

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Optimal Dynamic Operating Policies for a Tandem Queueing Service System

  • Hwang, Dong-Joon
    • 한국경영과학회지
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    • 제4권1호
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    • pp.51-67
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    • 1979
  • This paper considers the problem of determining an optimal dynamic operating policy for a two-stage tandem queueing service system in which the service facilities (or stages) can be operated at more than one service rate. At each period of the system's operation, the system manager must specify which of the available service rates is to be employed at each stage. The cost structure includes an operating cost for running each stage and a service facility profit earned when a service completion occurs at Stage 2. We assume that the system has a finite waiting capacity in front of each station and each customer requires two services which must be done in sequence, that is, customers must pass through Stage 1 and Stage 2 in that order. Processing must be in the order of arrival at each station. The objective is to minimize the total discounted expected cost in a two-stage tandem queueing service system, which we formulate as a Discrete-Time Markov Decision Process. We present analytical and numerical results that specify the form of the optimal dynamic operating policy for a two-stage tandem queueing service system.

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역 매표창구 최적화를 위한 시뮬레이션 설계 연구 (A Study on Simulation Design for the Optimum Number of Ticket Booth)

  • 김익희;이경태;박수명
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2009년도 춘계학술대회 논문집
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    • pp.1851-1858
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    • 2009
  • As the ticket issuing methods have been diversified for the convenience of the passengers such as ticketless service(SMS ticket, e-ticket, home ticket), automatic ticket issuing machine and consignment ticket sale, maintaining the current number of ticket booth has been becoming a issue. This study is designed to simulation for the optimum number of ticket booth and which can affect an efficient operation of train station and improvement of customer convenience. This study is proceeding and will contribute to minimize customer waiting time at the ticket booth. In addition, presenting the optimum number of booth is expected to have an effect on the increase of productivity and cost savings.

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M/M(a, b ; ${\mu}_k$)/1 배치 서비스 대기모델에 대한 연구 (A Study on M / M (a, b ; ${\mu}_k$) / 1 Batch Service Queueing Model)

  • 이화기;정경일
    • 대한산업공학회지
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    • 제21권3호
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    • pp.345-356
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    • 1995
  • The aim of this paper is to analyze the batch service queueing model M/M(a, b ; ${\mu}_k/1$) under general bulk service rule with mean service rate ${\mu}_k$ for a batch of k units, where $a{\leq}k{\leq}b$. This queueing model consists of the two-dimensional state space so that it is characterized by two-dimensional state Markov process. The steady-state solution and performane measure of this process are derived by using Matrix Geometric method. Meanwhile, a new approach is suggested to calculate the two-dimensional traffic density R which is used to obtain the steady-state solution. In addition, to determine the optimal service initiation threshold a, a decision model of this queueing system is developed evaluating cost of service per batch and cost of waiting per customer. In a job order production system, the decision-making procedure presented in this paper can be applicable to determining when production should be started.

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Travel-Time 모델을 이용(利用)한 최적(最適) 서어비스 수준(水準) 결정(決定)에 관한 연구(硏究) (A Study on the Determination of the Optimal Service Level by the Travel-Time Models)

  • 박병기;정종식
    • 품질경영학회지
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    • 제17권2호
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    • pp.142-148
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    • 1989
  • In order to determine the level of service which minimizes the total of expected cost of service and the expected cost of waiting for that service, the important considerations are to evaluate the distance traveled to and from a service facility (D) and the expected number of mechanics in queueing system (L). The travel-time models are very useful when the servers must travel to the customer from the service facility. Thus, in this paper we studied on the determination of the optimal service level by the travel-time models. In order to decide the optimal service level, (D) has been introduced as a uniform distribution and (L) has been introduced as M/M/S model of queueing theory.

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역 매표창구수 최적화 시뮬레이션 설계 연구 (A Study on Simulation Design for the Optimum Number of Ticket Booth)

  • 김익희;이경태;김창훈;금기정
    • 대한교통학회지
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    • 제28권2호
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    • pp.77-85
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    • 2010
  • 승차권 발매 유형의 다변화 및 무인 발권 비율이 증가됨에 따라 효율적 역 운영을 위해 역사내 매표창구수 최적화 문제가 제기되고 있다. 기존 선행 연구에서 고객 발권특성 및 서비스 시간 특성, 발권 현황 등에 대해 분석 제시한 바 있으나, 향후 발권 환경 변화에 따른 정책 의사결정을 위해 보다 객관적이고 신뢰할 수 있는 결과 도출이 요구되었다. 이에 본 연구에서는 현재 운영중인 주요 역의 매표창구 발권 현황 Data를 근거로 하여 역 매표창구수 최적화 및 민감도 분석을 위한 시뮬레이션을 구현하였으며, 매표창구수 변화에 따른 민감도 분석 결과 역별 발권 및 운영 특성에 따라 다소 차이는 있으나 최소 1개~7개까지 축소 운영이 가능할 것으로 검토되었다. 향후 매표창구 변화 운영에 따른 발권 실적 분석을 통해 시뮬레이션 결과에 대한 지속적 검증을 수행할 계획이며 역 매표창구에서의 고객 대기시간 최소화 및 운영비용 절감을 위한 효율적 매표창구 운영 방안 수립시 기여할 것으로 기대된다.

Which Node of Supply Chain Suffers Mostly to Disruption in the Pandemic?

  • NGUYEN, Tram Thi Bich
    • 유통과학연구
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    • 제19권11호
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    • pp.59-68
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    • 2021
  • Purpose: The Covid-19 pandemic has had excessively severe impacts on all the nodes and edges of any supply chain due to changes in consumer behaviours and lockdown restrictions from governments among countries. This article aims to provide a simulating experiment on how a supply chain deals with supply disruption risks by flexibility in the inventory level of each sector as a buffer considering the overall cost to fulfil demand in the market. Research design, data and methodology: Agent-based simulation techniques are used to determine the cost-efficiency and customer waiting time related to varying inventory levels of each member in the supply chain when using inventory buffers. Findings: This study has shown that any sudden changes in the inventory level of each sector are likely to impact the rest of the supply chain. Among all sectors, the wholesaler will be impacted more severely than others. Also, the manufacturing sector is the most suitable node to adjust inventory depending on its manufacturing ability. Conclusion: The findings of the study provide insightful implications for decision-makers to adjust inventory levels and policymakers to maintain manufacturing activities in the context of the pandemic restrictions to deal with the excessive demand and potential supply disruption risks.

위탁급식업체에서의 조리사 근무 스케줄에 대한 효율적 관리방안에 관한 연구 -'K' 업장의 사례를 중심으로- (A Study on Effective Management Plans for Work Schedule of Cooks in Contracted Foodservice Companies)

  • 김하윤;반주원;천희숙
    • 한국조리학회지
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    • 제12권1호
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    • pp.188-202
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    • 2006
  • With large corporations entering into the foodservice market, competitions among those foodservice providers became intense, leading to differentiated quality services in terms of portioning out the meal, its portion and waiting time, not to mention food quality. The purpose of providing foodservice is to satisfy its customers, to secure optimum level of profits, and attain continuous quality improvement. To have such purpose attained, all other factors affecting the foodservice should be allowed to play a role. The intensity of the work performed by the employees should be maintained at a steady level and systematically controlled. 'Service First’ principles upholding that customer satisfaction comes from good service should be applied at all times; customer satisfaction comes from the satisfaction of the employees. Customer satisfaction through good service will contribute to an increase in revenue which we get by subtracting operating expenses from the total sales, as it will lead to concluding a long-term supply contract or renewing the existing contract. To keep the operating expenses to the minimum level, it is important to effectively perform the cost control. Since personnel expenses occupy a large portion of the operating expenses, it is imperative to effectively control the labor costs. For this reason, this study will present an effective program for disposition of men with a large organization being centered around, where the number of people served at the mess hall varies greatly depending on a day of the week and a mealtime of the day.

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특송소화물 배송완료시간 최소화를 위한 차량경로문제 연구 (Study on Vehicle Routing Problem with Minimum Delivery Completion Time)

  • 이상헌
    • 대한교통학회지
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    • 제22권7호
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    • pp.107-117
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    • 2004
  • 특송 소화물 수송은 상품의 생산과 소비에 직결되어 있으며 소비자에 대한 원활한 소화물 수송이 경제에 미치는 영향이 지대하므로 그 중요성은 날로 증대하고 있다. 특히, 소비자 중심의 다 빈도 소량 운송시대로의 전환과 택배 등 특송 소화물 운송 산업의 활성화에 대한 화물수송 증가추세에 비해 적절한 계획 및 정책이 결여되어 있는 실정이다. 본 논문에서는 물류센터(단지)에서 모든 고객에게 수 배송을 가장 빠른 시간 내에 완료하여 고객이 서비스를 받기 위해 대기하는 시간을 최소화하는 차량경로를 결정하는 배송완료시간 최소화를 위한 차량경로모형을 제시한다. 본 연구에서는 마지막으로 방문을 받는 수요자의 대기시간을 최소화하는 개념으로서 생산문제와 비교하면 단위시간당 동일한 비용이 지출된다고 가정 할 때 모든 제품의 생산 및 판매까지의 총 비용을 최소화하는 것이 고전적인 차량경로문제라고 본다면 모든 제품의 생산완료 시점을 최소화하여 납기일을 단축시키는 것이 특징으로 볼 수 있다. 본 수리모형이 고전적인 차량경로문제와 구별되는 개념 중 하나는 각 차량의 마지막 방문수요지에서 물류센터로 복귀하는 시간은 고려하지 않으며 이에 따라 동일한 수요자를 방문하더라도 방문순서에 따라서 이동시간이 상이한 것과 또한 차량들이 방문하는 총 이동시간이 동일하더라도 경로 변경에 따라 모든 수요자 중 가장 마지막에 방문을 받는 수요자의 대기시간을 단축할 수 있다. 일반적으로 이러한 모형은 배송을 완료하는 시점이 중요시 되는 특송 소화물, 신문배송 문제, 신선함을 요하는 상품 또는 퀵 서비스 등 다양한 서비스 문제에 확대 적용할 수 있다. 제시된 모형은 ILOG Cplex 및 Solver를 활용하여 기존 차량경로문제와 비교하여 다양한 고객 및 차량 수에 대하여 최적해에 근접한 해를 쉽게 구할 수 있다.