• 경영과학
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• 제17권1호
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• pp.41-54
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• 2000

in the real world situations that some jobs need be processed only on certain limited machines frequently occur due to the capacity restrictions of machines such as tools fixtures or material handling equipment. In this paper we consider n-job non-preemptive and m parallel machines scheduling problem having two machines group. The objective function is to minimize the sum of earliness and tardiness with different release times and due dates. The problem is formulated as a mixed integer programming problem. The problem is proved to be Np-complete. Thus a heuristic is developed to solve this problem. To illustrate its suitability and efficiency a proposed heuristic is compared with a genetic algorithm and tabu search for a large number of randomly generated test problems in ship engine assembly shop. Through the experimental results it is showed that the proposed algorithm yields good solutions efficiently.

• 한국항해항만학회지
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• 제35권1호
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• pp.63-70
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• 2011

본 연구는 컨테이너 터미널에서 선박의 선적작업을 위한 선석배정 및 크레인 할당문제를 동시에 결정하는 문제를 다루고 있다. 실제 컨테이너 터미널에서 고려하고 있는 다양한 형태의 제약을 고려하여 선석계획 및 크레인할당 문제에 대한 혼합정수모델을 제시하였다. 제안된 문제에 대해 좋은 해를 짧은 시간 안에 구하기 위하여 발견적 해법을 제시하였다. 또한 수치예제를 이용하여 제시된 발견적 기법의 수행도를 비교분석하였다. 분석결과 제시된 기법은 짧은 시간 안에 좋은 해를 제공하는 것으로 나타났다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전력기술부문
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• pp.30-32
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• 2006

New building, reinforcement, maintenance and test of power equipments are always necessary in a power system. Our power system is getting old and the total power capacity is also getting large, so power equipment outages are getting often. Power euipment outages make less margine for a stable condition of a power system operation. Therefore, through overviews and countermeasures against the outage should be made in order to be in a stable operational conditions during the outage. We have too many outages over 300 per month in our power system. So, we can't have enough time to study our power system and to make countermeasures without a helping program. This program is designed to give various and appropriate informations necessary for an outage scheduling. By applying this program, we can raise the job efficiency high and spare the time spent. So we can afford to do through system studies and make good countermeasures. I think this program can contribute greately to power system stable operation.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회/대한산업공학회 2003년도 춘계공동학술대회
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• pp.744-748
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• 2003

Developing an interactive satellite multi­media system, such as a digital video broadcasting (DVB) return channel via satellite (RCS) system, is gaining popularity over the world To accommodate the increasing traffic demand we are motivated to investigate an alternative for improving return channel utilization We develop an efficient method for optimal packet scheduling in an interactive satellite multimedia system using hybrid CDMA/TDMA channels. We formulate the timeslot-code assignment problem as a binary integer programming (BIP) problem, where the throughput maximization is the objective, and decompose this BIP problem into two sub-problems for the purpose of solution efficiency. With this decomposition, we promote the computational efficiency in finding the optimal solution of the original BIP problem Since 2001, ETRI has been involved in a development project where we have successfully completed an initial system integration test on broadband mobile Internet access via Ku-band channels using the proposed resource allocation algorithm.

• 전자공학회논문지B
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• 제32B권3호
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• pp.11-23
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• 1995

In this paper, a parallel pipelined processor model which acts as a small VLIW processor architecture and a scheduling algorithm for extracting instruction-level parallelism on this architecture are proposed. The proposed model has a dual-instruction mode which has maximum 4 basic operations being executed in parallel. By combining these basic operations, variable instruction set can be designed for various applications. The scheduling algorithm schedules basic operations for parallel execution and removes pipeline hazards by examining data dependency and resource conflict relations. In order to examine operation and evaluate the performance,a C compiler and a simulator are developed. By simulating various test programs with the compiler and the simulator, the characteristics and the performance result of the proposed architecture are measured.

• 한국경영과학회지
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• 제25권2호
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• pp.47-57
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• 2000

In this paper we consider an n-job non-preemptive and identical parallel machine scheduling problem of minimizing the sum of earliness and tardiness with different release times and due dates. In the real world this problem is more realistic than the problems that release times equal to zero or due dates are common. The problem is proved to be NP-complete. Thus a heuristic is developed to solve this problem To illustrate its suitability a proposed heuristic is compared with a genetic algorithm for a large number of randomly generated test problems. Computational results show the effectiveness and efficiency of proposed heuristic. In summary the proposed heuristic provides good solutions than genetic algorithm when the problem size is large.

• 대한산업공학회지
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• 제13권1호
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• pp.11-24
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• 1987

Automatic Guided Vehicle Systems feature battery powered driverless vehicles with programming capabilities for path selection and positoning. Vehicles serve the machines in shop, following a guide path system installed on the shop floor. The basic problem in the system is to determine a fixed set of vehicle routes of minimal total distance(time) while keeping capacity and distance(time) constraints. In this paper, a heuristic algorithm is presented for scheduling the automatic guided vehicles. The algorithm routes the machines based on their distances and polor coordinate angles, taking into account the structural feature of the system. Computational experiments are performed on several test problems in order to evaluate the proposed algorithm. Finally, a framework for dealing with the case where supplies from the machines are probabilistic is described.

• 대한전기학회논문지:전력기술부문A
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• 제48권8호
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• pp.917-923
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• 1999

This paper proposes an efficient method of hydro-thermal scheduling in coordination with head variation and hydraulically coupled plants using Evolutionary Programing(EP). Based on the EP technique, the proposed algorithm is capable of determining the global optimal solutions. The constraints such a power balance condition, water available condition and transmission losses are embedded and satisfied throughout the proposed EP approach. The effectiveness of the proposed approach is demonstrated on the test systems and compared to those of other method. The results show that the new approach obtains a more highly optimal solutions than the conventional other methods such as newton-raphson method, Dynamic Programming(DP), LU factorization.

• Journal of information and communication convergence engineering
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• 제1권2호
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• pp.93-97
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• 2003

This paper proposes a new generation scheduling algorithm which can consider total quantity of contamination and energy limits based on Lagrangian Relaxation. First, we formulate a Lagrangian function which consider quantity of contamination including substitution of fuel, and quantity of fuel. Second, we developed Multi-state S.U.D.P. which can treat multiple fuels. Third, we propose an effective generation scheduling algorithm including Multi-state S.U.D.P.. As a results, unit commitment and generating power can be obtained to meet the environmental and fuel constraints with fuel substitution. By applying it to the test system, effectiveness of the method is verified.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권7호
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• pp.2434-2454
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• 2021

This paper developed the software testing factory-cloud testing platform (STF-CTP) to address the software compatible issues in various smart devices. Software developers who only require uploading the application under test (AUT) and test script can test plenty of smart devices in STF-CTP. The challenge for the cloud test platform is how to optimize the resource and increase the performance in the limited resource. This paper proposed a new scheduling mechanism and a new process of the system operation which is based on the OpenStack platform. We decrease about 40% memory usage of OpenStack server, increase 3% to 10% Android device usage of STF-CTP, enhance about 80% test job throughput and reduces about 40% test job average waiting time.