• 대한산업공학회지
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• 제34권3호
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• pp.318-327
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• 2008

This paper considers a single-machine scheduling problem with availability constraints. In many realistic situations, machines may not be always available due to various reasons such as maintenance, breakdown and repair. However, most literature on scheduling assume that the machines are available at all times. This paper deals with a single-machine scheduling problem with periodic maintenance. If the maintenance decision is made jointly with the job scheduling, the system will be more effective. The objective is to minimize the total completion time of jobs. This problem is proved to be NP-hard in the strong sense. The proposed breaking heuristic(BH) algorithm rule is established by some theorems and conditions. Our computational results show that the BH algorithm is much more efficient than existing heuristic.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2007년도 추계학술대회 및 정기총회
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• pp.309-312
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• 2007

We consider a proportionate flow shop problem with controllable processing times. The objective is to minimize the sum of total completion time and total compression cost, in which the cost function of compressing the processing times is non-decreasing concave. We show that the problem can be solved in polynomial time by reducing it to a polynomially solvable 0-1 unconstrained quadratic program.

• 대한산업공학회지
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• 제10권1호
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• pp.41-45
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• 1984

A resource constrained scheduling problem that involves trade-off between resources and time is considered. Models are considered. Models are presented as zero-one integer program and objectives of models include minimum project completion time and minimum total project cost.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1993년도 춘계공동학술대회 발표논문 및 초록집; 계명대학교, 대구; 30 Apr.-1 May 1993
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• pp.343-352
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• 1993

In this study, a modified algorithm for the exchange heuristic is developed and applied to a resource-constrained scheduling problem. The problem involves multiple projects and multiple resource categories and allows flexible resource allocation to each activity. The objective is to minimize the maximum completion time. The exchange heuristkc is a multiple pass algorithm which makes improvements upon a given initial feasible schedule. Four different modified algorithms are proposed. The original algorithm and the new algorithms were compared through an experimental investigation. All the proposed algorithms reduce the maximum completion time much more effectively than the original algorithm. Especially, one of four proposed algorithms obviously outperforms the other three algorithms. The algorithm of the best performance produces significantly shorter schedules than the original algorithm, though it requires up to three times more computation time. However, in most situations, a reduction in schedule length means a significant reduction in the total cost.

• 한국임상수의학회지
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• 제40권6호
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• pp.423-428
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• 2023

The mouse kidney transplantation model serves as an invaluable tool for exploring various aspects of the transplant process, including acute rejection, cellular and humoral rejection, ischemia-reperfusion injury, and the evaluation of novel therapeutic strategies. However, conducting venous anastomosis in this model poses a significant challenge due to the thin and pliable characteristics of the renal vein, which often obstruct clear visualization of the resected vein's edge. This study proposes the adoption of a two stay suture technique to enhance the visualization of the renal vein's edge, thereby facilitating efficient and successful venous anastomosis. A total of 22 mice served as kidney donors in this study. The conventional anchoring suture technique was employed for venous anastomosis in 11 of these mice, while the remaining 11 underwent the two stay suture technique. The anastomosis duration and completion rates were then compared between these two groups. The conventional anchoring suture technique yielded an average anastomosis time of 29 minutes and a completion rate of 64%. In contrast, the two stay suture technique demonstrated a substantial improvement, with an average anastomosis time of 14 minutes and a completion rate of 100%. The two stay suture technique offers a promising solution to enhance visualization during venous anastomosis in murine kidney transplantation. This technique may particularly benefit novices by enabling them to perform venous anastomosis more easily, swiftly, and successfully.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1993년도 춘계공동학술대회 발표논문 및 초록집; 계명대학교, 대구; 30 Apr.-1 May 1993
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• pp.6-15
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• 1993

A generalization of one machine maximum lateness minimization problem is considered. There are one achine with controllable speed and n weighting jobs $J_{j}$, j=1, 2, ..., n with ambiguous duedates. Introducing fuzzy formulation, a membership function of the duedate associated with each job $J_{j}$, which describes the satisfaction level with respect to completion time of $J_{j}$. Thus the duedates are not constants as in conventional scheduling problems but decision variables reflecting the fuzzy circumstance of the job completing. We develop the polynomial time algorithm to find an optimal schedule and jobwise machine speeds, and to minimize the total sum of costs associated with jobwise machine speeds and dissatisfaction with respect to completion times of weighting jobs. jobs.

• 대한산업공학회지
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• 제33권1호
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• pp.76-85
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• 2007

A reliability acceptance sampling plan (RASP) consists of a set of life test procedures and rules for eitheraccepting or rejecting a collection of items based on the sampled lifetime data. Most of the existing RASPs areconcerned with the case where test items are available at the same time. However, as in the early stage ofproduct development, it may be difficult to secure test items at the same time. In such a case, it is inevitable toconduct a life test using sequentially supplied samples.In this paper, it is assumed that test items are sequentially supplied, the lifetimes of test items follow anexponential disthbution, failures are monitored continuously, arrival times of test items are known, and thenumber of test items at each arrival time is given. Under these assumptions, RASPs are developed by deter-mining the test completion time and the critical value for the maximum likelihood estimator of the mean lifetimesuch that the producer and consumer risks are satisfied. Then, the developed plans are compared to thetraditional Type-I censored RASPs in terms of the test completion time. Computational results indicate that thetest completion time of the developed RASP is shorter than that of the traditional Type-I censored plan in mostcases considered. It is also found that the superiority of the developed RASP becomes more prominent as theinter-arrival times of test items increase and/or the total number of test items gets larger.

• 한국산업정보학회논문지
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• 제4권2호
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• pp.81-87
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• 1999

본 연구에서는 단일 공정의 생산시스템을 대상으로 n개 작업에 있어서의 시간/비용의 트레이드-오프에 있어서 작업순서의 평가기준과 자원할당 비용의 평가기준을 동시에 고려한 2목적 스케쥴링 문제들을 제안한다. 우선 가공작업의 총체류시간(total flow time)과 납기(due date)의 평가기준에 관한 2목적의 유효스케쥴을 구하는 해법을 제안한다. 그리고 이러한 평가기준과 이에 관련된 자원할당의 비용을 동시에 최소화하는 2목적의 해법을 제안한다.

• Journal of applied mathematics & informatics
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• 제17권1_2_3호
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• pp.419-432
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• 2005

In this paper we study the no-wait or no-idle permutation flowshop scheduling problem with an increasing and decreasing series of dominating machines. The objective is to minimize one of the five regular performance criteria, namely, total weighted completion time, maximum lateness, maximum tardiness, number of tardy jobs and makespan. We establish that these five cases are solvable by presenting a polynomial-time solution algorithm for each case.

• 한국통신학회논문지
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• 제40권9호
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• pp.1802-1807
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• 2015

클라우드 컴퓨팅 서비스는 가상화 기술을 이용하여 물리적인 IT 자원을 VM 단위로 사용자들에게 비용을 받고 제공하는 서비스이다. 그 중 클라우드 컴퓨팅 기반 가용 자원 경매 모델은 서비스 제공자의 가용 자원을 경매를 통해서 사용자들에게 제공 하는 서비스이다. 서비스 이용자들은 제한 시간 안에 그들의 작업을 처리하기 위해 서비스 제공자에게 자원 이용에 대한 입찰가격을 제시하고 낙찰 가격 보다 높은 경우 자원을 제공 받는다. 본 논문에는 Amazone EC2에서 서비스 이용자의 작업을 완료하는데 요구되는 스팟 인스턴스에 대한 총 경비를 최소화하는 입찰 기법을 제안한다. 일반적으로, 서비스 이용자는 자원을 할당 받기 위해 높은 입찰 가격을 제시할 것이고, 그에 따라 낙찰 가격이 높아짐으로써 서비스 이용자의 실제 작업 비용은 높아지게 된다. 따라서 제안 입찰 기법을 이용하여 낙찰 가격을 낮춤으로써 서비스 이용자의 총 경비를 최소화 할 수 있다. 제안 기법의 성능 분석을 위해 실제 데이터를 이용하여 낙찰 가격과 실제 총 경비를 계산하고, 실제 낙찰 가격 기반의 입찰 기법과 비교함으로써 제안 기법의 성능을 입증하였다.