• 한국정보시스템학회지:정보시스템연구
• /
• 제25권4호
• /
• pp.105-119
• /
• 2016

Purpose 생산 일정계획 문제의 해법들은 일반적으로 총처리시간이 짧은 active 스케줄에 초점을 맞추어 해를 탐색하는 경우가 많다. 그러나 active 스케줄은 semi active 스케줄에 비해 생성하는 것이 까다롭기 때문에, 일정계획을 생성하는데 소요되는 계산 비용을 감안하면 semi active 스케줄을 적절히 활용하는 것이 도움이 될 수 있다. 이에, 본 논문에서는 동일한 생산 일정계획 문제에 active 스케줄기반 탐색 방법과 semi active 스케줄 기반 탐색 방법을 적용함으로써 이들의 성능을 비교해보고자 하였다. Design/methodology/approach 각 공정들의 작업장 할당 순서를 의미하는 permutation encoding 기반 유전 알고리즘을 고전적인 job shop 일정계획 문제에 적용하기 위해 본 논문에서는 active 스케줄 복호화 및 semi active 스케줄 복호화의 두 가지 복호화 방법을 소개하였으며, 이들은 공정들의 순열로부터 실행가능한 스케줄을 얻는데 사용되었다. Findings semi active 스케줄 기반 유전 알고리즘은 active 스케줄 기반 유전 알고리즘에 비해 최적해를 탐색하는데 소요되는 반복 횟수가 좀 더 많은 경향이 있었으나, 알고리즘 실행 시간을 훨씬 짧았다. 나아가, semi active 스케줄 복호화는 그 절차가 단순하여 이해하고 구현하기 용이하다는 장점이 있었다. 따라서, 효과적인 해 탐색 전략이 주어지는 경우에는 semi active 스케줄에 기반한 해법이 일정계획 문제 풀이에 도움이 될 수도 있을 것으로 보여진다.

• 산업공학
• /
• 제12권4호
• /
• pp.617-624
• /
• 1999

In order to maximize an availability of machine and utilization of space, the parallel machines scheduling problem with space limit is frequently discussed in the industrial field. In this paper, we consider a scheduling problem for assembly machine in ship engine assembly shop. This paper considers the parallel machine scheduling problem in which n jobs having different release times, due dates and space limits are to be scheduled on m parallel machines. The objective function is to minimize the sum of earliness and tardiness. To solve this problem, a heuristic is developed. The proposed heuristic is divided into three modules hierarchically: job selection, machine selection and job sequencing, solution improvement. To illustrate its effectiveness, a proposed heuristic is evaluated with a large number of randomly generated test problems based on the field situation. Through the computational experiment, we determine the job selection rule that is suitable to the problem situation considered in this paper and show the effectiveness of our heuristic.

• Industrial Engineering and Management Systems
• /
• 제4권1호
• /
• pp.1-22
• /
• 2005

This paper presents new scheduling heuristics, namely Mean Progressive Weighted Tardiness Estimator (MPWT) Heuristic Method and modified priority rules with sequence-dependent setup times consideration. These are designed to solve job shop scheduling problems with new performance measures - progressive weighted tardiness penalties. More realistic constraints, which are inter-machine overlapping sequence-dependent setup times, are considered. In real production environments, inter-machine overlapping sequence-dependent setups are significant. Therefore, modified scheduling generation algorithms of active and nondelay schedules for job shop problems with inter-machine overlapping sequence-dependent setup times are proposed in this paper. In addition, new customer-based measures of performance, which are total earliness and progressive weighted tardiness, and total progressive weighted tardiness, are proposed. The objective of the first experiment is to compare the proposed priority rules with the consideration of sequence-dependent setup times and the standard priority rules without setup times consideration. The results indicate that the proposed priority rules with setup times consideration are superior to the standard priority rules without the consideration of setup times. From the second experiment and the third experiment to compare the proposed MPWT heuristic approach with the efficient priority rules with setup times consideration, the MPWT heuristic method is significantly superior to the Batched Apparent Tardiness Cost with Sequence-dependent Setups (BATCS) rule, and other priority rules based on total earliness and progressive weighted tardiness, and total earliness and tardiness.

• 산업공학
• /
• 제11권3호
• /
• pp.1-13
• /
• 1998

This paper addresses a scheduling scheme for Flexible Flow Shop(FFS) in the case that a factory is a sub-plant of an electronic device manufacturing plant. Under this environment, job orders for the sub-plants in the production route are generated together with job processing time bucket when the customer places orders for final product. The processing time bucket for each job is a duration from possible release date to permissible due date. A sub-plant modeled FFS should schedule these jobs orders within time bucket. Viewing a Printed Circuit Board(PCB) assembly line as a FFS, the developed scheme schedules an incoming order along with the orders already placed on the scheduled. The scheme consists of the four steps, 1)assigning operation release date and due date to each work cells in the FFS, 2)job grouping, 3)dispatching and 4)machine allocation. Since the FFS scheduling problem is NP-complete, the logics used are heuristic. Using a real case, we tested the scheme and compared it with the John's algorithm and other dispatching rules.

• 품질경영학회지
• /
• 제16권1호
• /
• pp.32-42
• /
• 1988

The general n/m job-shop problem is easy to state what is required, but it is extremely difficult to make any progress whatever toward a solution. This paper was first to examine a heuristic procedure of general n/m scheduling generation focused on the procedure of MWRK (Most Work Remaining) presented by Giffler and Thompson (1960) among others. Then modified procedure was proposed to obtain better solution in light of the key measure of performance compared with that of the literature presented by Baker (1974). The modified procedure then has been extended to other example problem to test the better results and to assure the properness of application.

• 산업경영시스템학회지
• /
• 제16권28호
• /
• pp.165-171
• /
• 1993

The algorithm of Giffler and Thompson is modified for solving job shop scheduling problems related to the overlapping production The start-lag and stop-lag are also applied New priority rules for the overlapping production are proposed and the efficiency of them is compared with that of the classical priority rules.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2011년도 춘계학술대회 논문집
• /
• pp.729-730
• /
• 2011

• Industrial Engineering and Management Systems
• /
• 제12권2호
• /
• pp.151-160
• /
• 2013

In the past decades, several algorithms based on evolutionary approaches have been proposed for solving job shop scheduling problems (JSP), which is well-known as one of the most difficult combinatorial optimization problems. Most of them have concentrated on finding optimal solutions of a single objective, i.e., makespan, or total weighted tardiness. However, real-world scheduling problems generally involve multiple objectives which must be considered simultaneously. This paper proposes an efficient particle swarm optimization based approach to find a Pareto front for multi-objective JSP. The objective is to simultaneously minimize makespan and total tardiness of jobs. The proposed algorithm employs an Elite group to store the updated non-dominated solutions found by the whole swarm and utilizes those solutions as the guidance for particle movement. A single swarm with a mixture of four groups of particles with different movement strategies is adopted to search for Pareto solutions. The performance of the proposed method is evaluated on a set of benchmark problems and compared with the results from the existing algorithms. The experimental results demonstrate that the proposed algorithm is capable of providing a set of diverse and high-quality non-dominated solutions.

• Management Science and Financial Engineering
• /
• 제15권2호
• /
• pp.69-100
• /
• 2009

In this paper, we consider a relatively new two-machine flow shop scheduling problem where the unit time WIP cost increases as a job passes through various stages in the production process, and the objective is to minimize the total WIP (work-in-process) cost. Specifically, we study three special cases of the problem. First, we consider the problem where processing times on machine 1 are identical. Second, the problem with identical processing times on machine 2 is examined. The recognition version of the both problems is unary NP-complete (or NP-complete in strong sense). For each problem, we suggest two simple and intuitive heuristics and find the worst case bound on relative error. Third, we consider the problem where the processing time of a job on each machine is proportional to a base processing time. For this problem, we show that a known heuristic finds an optimal schedule.

• 산업경영시스템학회지
• /
• 제24권64호
• /
• pp.63-76
• /
• 2001

This paper presents a job-shop type flexible manufacturing system(FMS) scheduling problem and examines the effects of scheduling rules on the performance of FMS. Several machine and AGV scheduling rules are tested against the mean flow-time criterion. In this paper, I compare the rules under various experimental conditions by using an FMS simulation model. One of the objectives of this study is to discuss how the simulation-based scheduling problem can be operated. The other is to measure sensitivity of the rules to changes at inter arrival time, queue capacity, breakdown rates for machines and AGV, and AGV speed. Therefore, the results of simulation experiments were considered on FMS design and operating stages. A comprehensive bibliograph? is also presented in the paper.