• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.2369-2373
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• 2001

Usually the static scheduling algorithms such as DMS (Deadline Monotonic Scheduling) or RMS(Rate Monotonic Scheduling) are used for CAN scheduling due to its ease with implementation. However, due to their inherently low utilization of network media, some dynamic scheduling approaches have been studied to enhance the utilization. In case of dynamic scheduling algorithms, two considerations are needed. The one is a priority inversion due to rough deadline encoding into stricted arbitration fields of CAN. The other is an arbitration delay due to the non-preemptive feature of CAN. In this paper, an extended algorithm is proposed from an existing EDS(Earliest Deadline Scheduling) approach of CAN scheduling algorithm haying a solution to the priority inversion. In the proposed algorithm, the available bandwidth of network media can be checked dynamically by all nodes. Through the algorithm, arbitration delay causing the miss of their deadline can be avoided in advance. Also non real-time messages can be processed with their bandwidth allocation. The proposed algorithm can achieve full network utilization and enhance aperiodic responsiveness, still guaranteeing the transmission of periodic messages.

• 대한산업공학회지
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• 제17권1호
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• pp.83-94
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• 1991

This study is concerned with the scheduling problem for mixed-model assembly lines in Just-In-Time(JIT) production systems. The most important goal of the scheduling for the mixed-model assembly line in JIT production systems is to keep a constant rate of usage for every part used by the systems. In this study, we develop two heuristic algorithms able to keep a constant rate of usage for every part used by the systems in the single-level and the multi-level. In the single-level, the new algorithm generates sequence schedule by backward tracking and prevents the destruction of sequence schedule which is the weakest point of Miltenburg's algorithms. The new algorithm gives better results in total variations than the Miltenburg's algorithms. In the multi-level, the new algorithm extends the concept of the single-level algorithm and shows more efficient results in total variations than Miltenburg and Sinnamon's algorithms.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1028-1031
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• 1996

Dynamic scheduling is very important in constructing CIM and improving productivity of chemical processing systems. Computation at the scheduling level requires mostly a long time to generate an optimal schedule, so it is difficult to immediately respond to actual process events in real-time. To solve these problems, we developed dynamic scheduling algorithms such as DSMM(Dynamic Shift Modification Method), PUOM(Parallel Unit Operation Method) and UVVM(Unit Validity Verification Method). Their main functions are to minimize the effects of unexpected disturbances such as process time variations and unit failure, to predict a makespan of the updated dynamic schedule and to modify schedule desirably in real-time responding to process time variations. As a result, the algorithms generate a new pertinent schedule in real-time which is close to the original schedule but provides an efficient way of responding to the variation of process environment. Examples in a shampoo production batch process illustrate the efficiency of the algorithms.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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• pp.125-127
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• 1995

This paper describes the optimal operation scheduling technique using genetic algorithms on cogeneration systems with variable efficiency in case of bottoming cycle. Variable efficiency included nonlinear behavior is obtained by least square method based on the real data of industrial cogeneration systems. Genetic algorithms is coded as a vector of floating point numbers. The results of simulation are evaluated that the genetic algorithms can be applied to perform the operation scheduling.

• 산업공학
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• 제12권1호
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• pp.19-25
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• 1999

The time slot scheduling problem for a satellite cluster with an arbitrary number of satellite is considered, which is one of the most interesting problems in the satellite communication scheduling area. This problem is known to be NP-complete, and several heuristic algorithms have been proposed. In this paper, a new efficient algorithm is suggested, which has lower computational complexity and provides much better solution than other existing algorithms.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2007년도 하계종합학술대회 논문집
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• pp.19-20
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• 2007

IEEE 802.lie is a new standard to support Quality of Service. HCCA(HCF controlled channel access) is a channel access mechanism, which polls the Qos-stations, utilized by the HC in AP. In this paper, we proposed an efficient scheduling algorithm in HCCA and compared with existing algorithms. Extensive simulation has done in ns-2 and the simulation results show our algorithm outperforms existing algorithms.

• 산업경영시스템학회지
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• 제14권24호
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• pp.53-69
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• 1991

This paper is concerned with software developments for scheduling and sequencing of FMS. The scheduling algorithms are developed for 3 types of FMS:single machine type FMS, flowshop type FMS. assembly line type FMS. For the single machine type FMS. full enumeration algorithm is used. For the flowshop type FMS heuristic algorithms are developed. For the assembly type FMS the exsisting PERT/CPM algorithm is applied. Numerical examples are presented for illustration of each algorithm. Each soft ware program list are attached as appendices.

• 한국항공우주학회지
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• 제38권1호
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• pp.48-57
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• 2010

본 논문에서는 위성 임무 스케줄링을 효율적으로 수행하기 위한 스케줄링 최적화 알고리즘을 타부탐색 알고리즘과 유전 알고리즘을 이용해 디자인하고, 시뮬레이션을 수행한 비교 결과를 기술하였다. 위성 임무 스케줄링은 위성에게 요구된 작업들과 그에 따른 제한사항 및 다양한 변수들을 종합적으로 고려하여 상호간의 시간, 조건 등의 충돌을 회피함과 동시에 위성의 자원을 최대한 활용하여 운용할 수 있는 최적의 작업시간표를 생성하는 것이다. 위성 임무 스케줄링은 동시에 많은 변수를 고려해야 하기 때문에 연산양이 많고, 매 스케줄링 시 마다 동일한 과정을 반복적으로 수행해야 하므로, 스케줄링 최적화 알고리즘과 같은 위성 운영 자동화, 자율화가 요구되는 분야이다. 다양하게 이용되고 있는 두 가지 스케줄링 기법을 위성 임무 스케줄링 최적화에 적용해 보았다.

• Journal of Communications and Networks
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• 제18권3호
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• pp.523-530
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• 2016

We use both theoretical analysis and simulations to study the impact of crosspoint-queued (CQ) buffer size on CQ switch throughput and delay performance under different traffic models, input loads, and scheduling algorithms. In this paper, we present the following. 1) We prove the stability of CQ switch using any work-conserving scheduling algorithm. 2) We present an exact closed-form formula for the CQ switch throughput and a non-closed-form but convergent formula for its delay using static non-work-conserving random scheduling algorithms with any given buffer size under independent Bernoulli traffic. 3) We show that the above results can serve as a conservative guide on deciding the required buffer size in pure CQ switches using work-conserving algorithms such as the random scheduling, under independent Bernoulli traffic. 4) Furthermore, our simulation results under real-trace traffic show that simple round-robin and random work-conserving algorithms can achieve quite good throughput and delay performance with a feasible crosspoint buffer size. Our work reveals the impact of buffer size on the CQ switch performance and provides a theoretical guide on designing the buffer size in pure CQ switch, which is an important step toward building ultra-high-speed switch fabrics.

• 컴퓨터교육학회논문지
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• 제18권3호
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• pp.115-124
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• 2015

본 논문에서는 그리드 시스템의 스케줄링 알고리즘을 시뮬레이션 할 수 있는 웹 기반의 스케줄링 툴킷(GridTool2)를 소개한다. 그리고 기존 MinMin과 Suffrage 스케줄링 알고리즘에 통신비용을 적용하여 성능이 향상된 수정 알고리즘을 제안한다. GridTool2는 서버와 데이터베이스를 기반으로 웹 환경에서 동작하므로 별도의 컴파일이나 실행 환경을 구축하지 않아도 된다. GridTool2는 통신비용과 함께 성능분석을 위한 변수들을 웹에서 입력하며, 시뮬레이션 결과를 웹페이지에 나타낸다. 통신비용을 적용한 수정된 알고리즘의 향상된 성능을 확인하기 위하여 GridTool2를 사용하여 실험하였다. 실험 결과에 따르면 기존 알고리즘보다 통신비용을 고려한 수정 알고리즘의 성능이 향상되었으며, 특히 작업량이 많아지면 성능향상의 폭이 증가하는 것으로 확인되었다.