• 대한전기학회논문지
• /
• 제39권5호
• /
• pp.527-537
• /
• 1990

This paper describes an intelligent control-based job scheduler, named ESIJOBS, for flexible manufacturing system. In order to construct rulebase of this system, traditional rules of job scheduling in FMS are examined and evaluated. This result and the repetitional simulations with graphic monitoring system are used to form the rulebase of ESIJOBS, which is composed of three parts:six part selection rules, four machine center selection rules, and twenty-one metarules. Appropriate scheduling rule sets are selected by this rulebase and manufacturing system status. The performances of all simulations are affected by random breakdowns of major FMS components during each simulation. Six criteria are used to evaluate the performance of each scheduling. The two modes of ESIJOBS are simulated and compared with combinational 24 rule-set simulations. In this comparison ESIJOBS dominated the other rule-set simulations and showed the most excellent performance particularly in three criteria.

• 산업경영시스템학회지
• /
• 제21권48호
• /
• pp.213-222
• /
• 1998

The objective of this study is to develop a knowledge-based scheduler applying simulation and knowledge base. This study utilizes a machine induction to build knowledge base which enables knowledge acquisition without domain expert. In this study, the best job dispatching rule for each order is selected according to the specifications of the order information. And these results are built to the fact base and knowledge base using the attribute-oriented induction method and simulation. When a new order enters in the developed system, the scheduler retrieves the knowledge base in order to find a matching record. If there is a matching record, the scheduling will be carried out by using the job dispatching rule saved in the knowledge base. Otherwise the best rule will be added to the knowledge base as a new record after scheduling to all the rules. When all these above steps finished the system will furnish a learning function.

• International journal of advanced smart convergence
• /
• 제7권4호
• /
• pp.10-18
• /
• 2018

For the information services supporting requests of data items from a great number of mobile clients, wireless data broadcasting is an effective way because it can accommodate any number of clients. In the wireless data broadcasting, various air indexing schemes and data scheduling schemes have been developed in order to enable the clients to access their desired data items efficiently. The broadcasting system needs a method to simulate newly designed air indexing and scheduling schemes of the system, and to evaluate the performance parameters of the schemes. In this paper, we design an expandable and efficient simulation framework for the wireless data broadcasting based on the partition of data ID space. The framework can adopt regular and irregular space partition and evaluate various performance parameters of the broadcasting system. We implement a testbed of the broadcasting system using the framework, that adopts IIP, GDI and EXP as its air indexing schemes. We simulate the system using the testbed and evaluate the performance parameters of the system. Thus, we show the efficiency and expandability of the designed and implemented framework.

• 한국시뮬레이션학회논문지
• /
• 제28권4호
• /
• pp.45-56
• /
• 2019

장치장 운영전략을 주제로 한 많은 선행연구들은 장치장에 도착한 트럭들을 대상으로 야드 크레인의 작업시간을 최소화할 수 있는 작업순서를 결정했다. 하지만 실제 현장에서는 이미 장치장에 도착한 트럭들의 작업순서를 바꾸는 것은 거의 불가능하여, 도착순서에 따라 작업을 처리해주는 비교적 단순한 전략을 주로 적용해왔다. 이 방식은 작업순서에 대한 혼잡을 줄일 수 있고 관리가 편하다는 장점이 존재하지만, 간섭대기시간과 공차시간의 증가로 작업시간이 증가하는 문제점이 있다. 본 연구에서는 트럭이 야드 장치장에 도착하기 이전에 트럭의 작업 순서를 결정하는 스케줄링 방법을 제안했다. 트럭 도착 이전에 작업을 할당해 주기 위해 트럭의 도착 예정 시간을 추정할 수 있는 Container Pre-Information Notice 정보를 활용하였다. 연구에서 제안하는 스케줄링 방법의 효과성을 검증하기 위해 실제 부산컨테이너터미널의 설비 레이아웃 및 데이터를 이용하여 현업의 방식과 본 연구의 스케줄링 방식을 비교하였다. 그 결과 크레인 작업 시간에 영향을 미치는 공차이동 및 간섭 대기시간이 감소하여 평균 작업 처리 시간이 감소한 것을 확인하였으며, 또한 내부트럭의 대기시간과 외부트럭의 체감 대기시간이 감소하는 효과가 있었다.

• 인터넷정보학회논문지
• /
• 제6권2호
• /
• pp.25-35
• /
• 2005

실시간 스케줄링 알고리즘에서는 비율단조(RM) 스케줄링 알고리즘과 마감시한(EDF) 스케줄링 알고리즘이 가장 일반적으로 사용되고 있다. 이러한 알고리즘에서는 태스크 집합의 전체 이용율 값을 가지고 수행 가능성을 판별하였다. 그러나 임의의 태스크에서 이용율 값이 초과되면 개별 태스크의 한계성을 전혀 예측할 수 없는 문제점이 있었다. 본 논문에서 제안한 알고리즘은 이용율 값이 초과한 태스크를 예측하고, 개별 태스크의 이용율 값을 기반으로 스케줄링 가능성 여부를 판단하는 방법을 제시하였다. 또한, 실시간 시스템에서 스케줄링 가능성 검사의 한계성을 시뮬레이션을 통해 예측하고 결과를 분석하였다.

• 한국경영과학회:학술대회논문집
• /
• 대한산업공학회/한국경영과학회 1994년도 춘계공동학술대회논문집; 창원대학교; 08월 09일 Apr. 1994
• /
• pp.250-250
• /
• 1994

• 한국경영과학회:학술대회논문집
• /
• 대한산업공학회/한국경영과학회 1996년도 춘계공동학술대회논문집; 공군사관학교, 청주; 26-27 Apr. 1996
• /
• pp.316-316
• /
• 1996

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제12권12호
• /
• pp.5800-5818
• /
• 2018

Interference may occur when several co-located wireless body area networks (WBANs) share the same channel simultaneously, which is compressed by resource scheduling generally. In this paper, a QoS-aware Adaptive Coloring (QAC) scheduling algorithm is proposed, which contains two components: interference sets determination and time slots assignment. The highlight of QAC is to determine the interference graph based on the relay scheme and adapted to the network QoS by multi-coloring approach. However, the frequent resource assignment brings in extra energy consumption and packet loss. Thus we come up with a launch condition for the QAC scheduling algorithm, that is if the interference duration is longer than a threshold predetermined, time slots rescheduling is activated. Furthermore, based on the relative distance and moving speed between WBANs, a prediction model for interference duration is proposed. The simulation results show that compared with the state-of-the-art approaches, the QAC scheduling algorithm has better performance in terms of network capacity, average delay and resource utility.

• Journal of Electrical Engineering and information Science
• /
• 제2권6호
• /
• pp.1-6
• /
• 1997

The scheduling problem of satisfying both 0/1 constraint and the timing constraint while minimizing the total error is NP-complete when the optional parts have arbitrary processing times. In this paper, we present a heuristic scheduling algorithm for 0/1 constraint imprecise systems which consist of communicating tasks running on multiple processors. The algorithm is based on the program graph which is similar to the one presented in[4]. To check the schedulability, we apply Lawler and Moore's theorem. To analyze the performance of the proposed algorithm, intensive simulation is done. The results of the simulation shows that the longest processing first selection strategy outperforms random or minimal laxity policies.

• 경영과학
• /
• 제13권2호
• /
• pp.147-161
• /
• 1996

Due-date is an important factor in Flexible Manufacturing System scheduling. Even though most of researchers have focused part selection and loading problem using fixed due-date assignment rules, FMSs consist of multi-function machines which facilitate alternative processes. This research investigates interactions of three dispatching mechanisms, three NSS (Next Station Selection) rules and four due-date assignment rules using simulation. Both cost-based and time-based performance measures are considered in this research.