• Journal of Korean Society of Industrial and Systems Engineering
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• v.25 no.3
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• pp.41-49
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• 2002

In the study, for the practical approaches of job shop scheduling, we propose the new dispatching rules of job shop scheduling in order to complement the practical applications in the existing researches. The assumed situation for the practical approaches considers the following; relaxation of assumption for capacity constraint by machine flexibility, the addition of the common use of jig and fixture, unbalanced machine workloads and duedate tightness, and produces fast rescheduling that reflects unexpected situations. The performance of the new dispatching rules is compared and analyzed with the existing methods through the computer experiments in the assumed conditions. The results can be useful to improving a field application of the job shop scheduling.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.14 no.24
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• pp.169-177
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• 1991

The Existing Protect schedulings are mathematical nodes upon which probability control is based. In fact, under the mechatronics environment in the new product design and development, statistical information is very poor or sometimes non-existent. Probabilistic PERT/CPM methods are not always satisfying because those methods suppose that it is possible to apply central- limit theorem and there exists a critical path which is much mart critical than all the other paths. Fuzzy project scheduling is possibility based scheduling. For this reason, the Fuzzy Project Scheduling essential to design, development and control the new product under the mechatranics environment. This paper deals with a modeling on the project scheduling which use fuzzy set theory. Fuzzy concepts in the project scheduling are shown to be very useful and easy to work with in the R & D system.

• Journal of Korean Institute of Industrial Engineers
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• v.35 no.4
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• pp.266-279
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• 2009

This paper focuses on the problem of scheduling wafer lots with limited waiting times between pairs of consecutive operations in a semiconductor wafer fabrication facility. For the problem of minimizing total tardiness of orders, we develop a priority rule based scheduling method in which a scheduling decision for an operation is made based on the states of workstations for the operation and its successor or predecessor operation. To evaluate performance of the suggested scheduling method, we perform simulation experiments using real factory data as well as randomly generated data sets. Results of the simulation experiments show that the suggested method performs better than a method suggested in other research and the one that has been used in practice.

• Journal of Intelligence and Information Systems
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• v.2 no.1
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• pp.75-91
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• 1996

제철소에서의 원료 운송 작업은, 선박에 선적된 원료를 하역하여 야드에 적치한 후, 제반 원료 소요공장까지의 벨트 컨베이어를 통한 원료 수송 작업을 의미한다. 본 연구에서는 원료 운송과 관련한 선박 접안, 원료 하역 및 벨트 컨베이어 수송 일정 계획을 효과적으로 수립하기 위하여 이단계 계획적 구조를 이용한 일정계획 휴리스틱을 개발하고 이를 구현하기 위한 전문가 시스템을 개발하였다. 이단계 계층적 구조는 상위 단계의 Scheduler 와 하위 단계의 복수개의 Dispatcher 로 구성되어 있다. 하위 단계의 Dispatcher는 주어진 제약조건하에서 단위 문제를 해결하고 이를 상위 단계의 Scheduler에게 보고하게 된다. 상위 단계의 Scheduler 는 전체적인 문제 해결의 우선 순위 결정 및 Dispatcher 간의 상층을 해결하는 역할을 맡게 된다. 이러한 계층적 구조를 이용한 분산처리를 통해 문제의 복잡성을 줄이고, 시스템 설계의 모듈화 및 유연성있는 시스템 구축이 가능하게 되었다. 본 시스템은 실시간 전문가 시스템 도구인 G2를 이용하여 SUN Workstation에서 개발되었다.

• Journal of Korean Institute of Industrial Engineers
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• v.24 no.3
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• pp.345-357
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• 1998

This paper focuses on production planning and scheduling problems in an assembly system operating on a make-to-order basis. Due dates are considered as constraints in the problems, that is, tardiness is not allowed. Since the planning problem is a higher-level decision making than the scheduling problem, the scheduling problem is solved using a production plan obtained by solving the planning problem. We suggest heuristic procedures in which aggregated information is used when the production planning problem is solved while more detailed information is used when the scheduling problem is solved. Since a feasible schedule may not be obtained from a production plan, an iterative approach is employed in the two procedures to obtain a solution that is feasible for both the production planning and scheduling problems. Computational tests on randomly generated test problems are done to show the performance of these algorithms, and results are reported.

• Journal of Korean Institute of Industrial Engineers
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• v.18 no.1
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• pp.91-104
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• 1992

Flowshop scheduling problem is known to be NP-complete. Since the optimization apporach like branch-and-bound is limited by exponentially growing computation time, many heuristic methods have been developed. Total tardiness is one of the criteria that the researchers have recently considered in flowshop scheduling. There, however, are few literatures which studied the general (m machine)-flowshop scheduling under the total tardiness criterion. In this paper, a heuristic scheduling method to minimize total tardiness at the (m machine, n job)-flowshop is presented. A heuristic value function is proposed to be used as a dispatching criterion in initial schedule generation. And the schedule improving procedure, by pairwise interchange of tardy job with the job right ahead of it, is introduced. Illustrative examles and simulated results are presented.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.19 no.39
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• pp.275-284
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• 1996

It can be made a definition that scheduling is a imposition of machinery and equipment to perform a collection of tasks. Ultimately scheduling is an assessment of taking order for which would be perform. So it is called "sequencing" in other words. In a job shop scheduling, the main object is to making delivery in accordance with the due date and order form customer, not to producing lots of quantity with minimizing mean flow time in a given time. Actually, in a company, they concentrate more in the delivery than minimizing the mean flow time. Therefore this paper suggest a new priority dispatching rule under consideration as below in a n/m job shop scheduling problem with due date. 1. handling/transportation time, 2. the size of customer order With this algorithm, we can make a scheduling for minimizing the tardiness of delivery which satisfy a goal of production.roduction.

• IEMEK Journal of Embedded Systems and Applications
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• v.6 no.1
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• pp.41-47
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• 2011

The Pfair scheduling algorithm, which is an optimal scheduling algorithm in the hard real-time multiprocessor environments, propose the necessary and sufficient condition for the schedulability and is based on the fixed quantum size. Recently, several methods that determine the optimal quantum size dynamically were proposed in the mode change environments. But these methods considered only the case in which the period of a task is increased or decreased. In this paper, we also consider the case in which the execution time of a task is increased or decreased, and propose new methods that determine the optimal quantum size dynamically.

• Journal of Korea Multimedia Society
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• v.22 no.4
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• pp.515-526
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• 2019

DOOH(Digital Out Of Home) advertising targets for reaching consumers through outdoor digital display medias. Traditionally, scheduling of advertisement contents over DOOH medias is usually done by operator's strategy, but an efficient ad scheduling strategy is not easy to find under various advertising contexts. In this paper, we present a context-aware factorization machine-based recommendation model for the scheduling under various advertising contexts, and provide analysis for understanding of the contexts' effects on advertising based on the recommendation model. Through simulation results on the dataset adapted from a real dataset of RecSys challenge 2015, it is shown that the proposed model and analysis based on the model will be effective for better scheduling of ad contents under advertising contexts over DOOH networks.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.735-737
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• 2009

Efficient scheduling for project is a major concern for software engineers. Industries simultaneously try to perform a variety method of projects with the resource-constrained scheduling. In this paper, genetic algorithm is presented to solve the scheduling problem of the resource-constrained scheduling and is substantiated with results.