• Journal of Korean Society of Industrial and Systems Engineering
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• v.20 no.42
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• pp.99-109
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• 1997

This paper considers to determine the processing workstation of parts and number of machines at workstations in multi-stage manufacturing system. Several part types are processed simultaneously through multi-stage, which consist of several workstations. The machines in each stage are identical in function, but non-identical in functional performance depending on workstations. Two models are suggested. One is assumed that a part type can be processed at the only one workstation in each processing stage. The other is assumed that a part type can be processed at several workstations. Decision criteria is to minimize the sum of the processing cost, travel cost and machine setup cost. Model formulations are presented, and a numerical example is shown.

• IE interfaces
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• v.7 no.2
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• pp.107-120
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• 1994

This study introduces a scheduling policy to achieve unmanned operations in machining shops representing the feature of both FMS and machining centers. The proposed policy considers the practical constraints in the machining shops such as lot sizes, multiple pallets, and jig/fixtures. In addition, rescheduling to cope with extraordinary events(eg., arrival of high-priority jobs and breakdown of machines) is included. Basically, the scheduling policy consists of four procedures; (1) selection of a job according to dispatching rule, (2) selection of a machine, (3) assignment of jobs to a multiple pallet for the unmanned operation during a certain shift, and (4) prevention of unexpected machine idle caused by constraints on jig/fixture.

• 한국항공운항학회:학술대회논문집
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• 2016.05a
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• pp.68-72
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• 2016

본 연구는 외국인 승무원의 팀 배속이 한국승무원과의 팀웍, 팀만족, 직무성과에 미치는 영향을 밝힘으로써 효율적인 외국인 승무원 관리방안을 모색하고 나아가 한국인 및 외국인 객실승무원의 단합된 팀웍으로 최상의 고객서비스를 제공하는 데 그 목적이 있다. 본 연구는 문헌연구와 실증연구를 바탕으로 진행하였으며 외국인 승무원의 팀 배속이 한국승무원과의 팀웍, 팀만족도, 직무성과에 미치는 영향 관계를 규명하였다. 설문은 K항공사 객실승무원을 대상으로 496부를 설문 조사하였으며 자료를 수집하고 분석한 결과, 외국인 승무원의 팀 배속이 한국승무원과의 팀웍, 팀만족, 직무성과에 긍정적인 영향을 미치는 것으로 나타났다.

• Proceedings of the KAIS Fall Conference
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• 2010.11b
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• pp.959-963
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• 2010

본 연구는 종합병원에서 간호부서의 인사관리에서 부서이동이 전문간호와 간호사의 직무만족에 어떤 영향을 미치는지에 관한 개념적 모형을 제시하고자 한다. 이는 간호부서의 효율적 인사관리로 간호사 자신의 긍정적인 수용자세로 간호사 자신의 발전은 물론 병원조직의 목표달성을 효율적으로 하기 위한 기초자료를 제공할 수 있으며, 추후 진행되는 실증적 분석에 의하여 보다 나은 방향의 부서이동 정책을 지원할 수 있을 것이다.

• Journal of the military operations research society of Korea
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• v.17 no.1
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• pp.43-60
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• 1991

Consider N queues without arrivals and with m identical servers. All jobs are independent and service requirements of jobs in a queue are i.i.d. random variables. At any time only one server may be assigned to a queue and switching between queues are allowed. A unit cost is imposed per job per unit time. The objective is to minimized the expected total cost. An flow approximation model is considered and an upperbound for the percentage error of best nonswitching policies to an optimal policy is found. It is shown that the best nonswitching policy is not worse than $11\%$ of an optimal policy For the stochastic model, we consider the case in which the service requirements of all jobs are i.i.d. with an exponential distribution. A longest first policy is shown to be optimal and a worst case analysis shows that the nonswitching policy which starts with the longest queues is not worse than $11\%$ of the optimal policy.

• IE interfaces
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• v.21 no.3
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• pp.333-342
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• 2008

Warehouses form an important link in a supply chain network. Among a variety of activities in warehouses, order picking is the process of retrieving a number of items out of storage to meet customer orders. Today, as the transactions through direct sales are wide spread, warehouses often receive a large amount of small orders to be handled within tight time windows, which makes fast and efficient order picking more important than ever. This paper examines a new order picking method where the concept of bucket brigade (BB) is applied. Bucket brigade is a way of dynamically coordinating workers who progressively perform a set of operations along a flow line. In bucket brigades, a worker is not assigned his jobs in a static way. Each worker takes a job from his predecessor when he is free. We identify some considerations when bucket brigades are applied to order picking activities. A new BB picking protocol is presented to improve existing BB picking protocols. Through simulation experiments, the performance of BB order picking is evaluated under various logistics environments.

• Journal of Communications and Networks
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• v.6 no.2
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• pp.147-155
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• 2004

In this paper, we propose an efficient sequencing technique, namely minimum Row time scheduling (MFTS), to manage variable-Iength message transmissions for single-hop passive starcoupled WDM optical networks. By considering not only the message length but also the state of the receivers and the tuning latency, the proposed protocol can reduce the average delay of the network greatly. This paper also introduces a new channel assignment technique latency minimizing scheduling (LMS), which aims to reduce the scheduling latency. We evaluate the proposed algorithm, using extensive discrete-event simulations, by comparing its performance with shortest job first (SJF) algorithm. We find that significant improvement in average delay could be achieved by MFTS algorithm. By combining the proposed message sequencing technique with the channel selection technique, the performance of the optical network could be further improved.

• IE interfaces
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• v.22 no.2
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• pp.144-152
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• 2009

Assembly line has been recognized as an efficient production system in mass production. However, the recent production environment characterized as mass customization urges production managers to transform a long assembly line to a number of short assembly cells. To maximize the utilization of resources in an assembly cell, it is important to have the line balanced. This paper presents a bucket brigade-based assembly cell. Bucket brigade is a way of coordinating workers who progressively perform a set of assembly operations on a flow line. Each worker follows a simple rule: perform assembly operations on a product until the next worker downstream takes it over; then go back to the previous worker upstream to take over a new assembly job. In this way, the line balances itself. The bucket brigade assembly cell is analyzed and compared with traditional assembly lines and general assembly cells. The paper also discusses some prerequisite requirements and limitations when the bucket brigade assembly cells are employed.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1955-1963
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• 2008

How can a train move? While a car is driven by a driver who gets the traffic information and takes the road, a train is operated on the designated(or predetermined) track by the operator or the control center. There have been a great deal of changes and evolutions in the railroad environment. Along with these transitions, there have been also a considerable amount of changes in the control center. There has been no detailed analysis for the control center even though its importance has been recognized. It goes without saying that CCC(Central Control Center)'s importance as the core of the train driving system. Such an importance is true for the automated driving system such as the light rail system. Therefore this paper analyzes the CCC of AREX(Airport Express) from the various aspects, i.e., organization, personnel assignment, the way of working, qualification and job analysis for the operator.

• Journal of the Korea Safety Management & Science
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• v.11 no.2
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• pp.111-115
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• 2009

As shown in the accident analysis from 2007, it has been found that causes of accidents on large-scale projects are different from those found in general construction projects. A 300-question survey regarding systematic and practical aspects of safety problems at construction sites was distributed to ten (10) different companies. Participants were to respond subjectively, so that the results could be used to assemble the first formal questionnaire survey. They were collected and compiled by an advisory committee for this study. The resulting surveys were then sent to the division chiefs of the top 100 construction companies in Korea, in order to improve the response rate. The Department of Safety & Health Direction, and the :Ministry of Labor, ROK sent the same sheets to medium and small construction companies that placed within 101-200th of all Korea construction companies. The above safety engineers were classified into four (4) levels, from 1st to 4th, followed by the project dollar amount and risk level. Formulae were developed to assign safety engineers to construction sites by engineer level, the project dollar amount, and the project risk level. Conclusions are summarized as follows: 1) Reviewing the assignment system of experienced safety engineers to large scaled projects - The more experienced the engineers assigned to a project, the higher the level of accident prevention. 2) Enforcing the assignment of advanced level safety engineers to large-scaled sites - At least one advanced-level safety engineer should be assigned to construction sites with projects valued at $15million USD (15,000,000,000). 3) For assigning safety engineers by risk level - Twenty models have been developed to calculate the number of safety engineers to be assigned by risk level. In the future, risk level for each job should be established by the government (as is now the practice in Germany).