• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2003년도 추계학술대회 및 정기총회
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• pp.85-88
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• 2003

In case that any jobs in a Job Shop can be scheduled on more than one machine and may have flexible operation sequences, with considering such case it is very difficult and complex to make the optimal process plans and scheduling. But they should be considered for an integrated model to perform more effective process planning and scheduling in this job shop problem. In this paper, we propose GA-based scheduling method to integrate effectively the problem of alternative machines, alternative operation sequences and scheduling. The performance of proposed GA is evaluated through comparing integrated scheduling with not integrated scheduling in molding company with alternative machines and operation sequences. Also, we use benchmark problems to evaluate performance. The scheduling method in this research will apply usefully to real world scheduling problems.

• 기술사
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• 제19권2호
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• pp.21-25
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• 1986

Structure-borne noise due to forced vibration which is originated from subway operation and transmitted to buildings in order of rail-wood tie-concrete bed-structure-soil-building foundations-members of building results in social problem of environmental pollution. Moreover this becomes a serious problem because of the increment of surface traffic and subway operation made by meeting traffic system in crowded cities. Since subway is constructed along the principal road or through the residential area and as the worst case may be, building foundations is contact with top part of subway structure, it is possible that vibration resonance results in fatal damage of buildings. And, structure-borne vibration noise due to subway operation at late and early hours have the residents suffer from insonmia, restlessness and so on. Therefore, to satisfy the future need concerning the environmental protection, this report deals with the influence of structure-borne vibration noise on the basis of the characteristics of Seoul Subway System.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권9호
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• pp.3751-3770
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• 2015

Many sorts of image processing software facilitate image editing and also generate a great number of doctored images. Forensic technology emerges to detect the unintentional or malicious image operations. Most of forensic methods focus on the detection of single operations. However, a series of operations may be used to sequentially manipulate an image, which makes the operation detection problem complex. Forensic investigators always want to know as much exhaustive information about a suspicious image's entire processing history as possible. The detection of the operation chain, consisting of a series of operations, is a significant and challenging problem in the research field of forensics. In this paper, based on the histogram distribution uniformity of a manipulated image, we propose an operation chain detection scheme to identify histogram equalization (HE) followed by the dither-like operation (DLO). Two histogram features and a local spatial feature are utilized to further determine which DLO may have been applied. Both theoretical analysis and experimental results verify the effectiveness of our proposed scheme for both global and local scenarios.

• International Journal of Aeronautical and Space Sciences
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• 제17권1호
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• pp.89-100
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• 2016

Given the unpredictability of the space environment, satellite communications are manually performed by exchanging telecommands and telemetry. Ground support for orbiting satellites is given only during limited periods of ground antenna visibility, which can result in conflicts when multiple satellites are present. This problem can be regarded as a scheduling problem of allocating antenna support (task) to limited visibility (resource). To mitigate unforeseen errors and costs associated with manual scheduling and mission planning, we propose a novel method based on a genetic algorithm to solve the ground support problem of multiple satellites and antennae with visibility conflicts. Numerous scheduling parameters, including user priority, emergency, profit, contact interval, support time, remaining resource, are considered to provide maximum benefit to users and real applications. The modeling and formulae are developed in accordance with the characteristics of satellite communication. To validate the proposed algorithm, 20 satellites and 3 ground antennae in the Korean peninsula are assumed and modeled using the satellite tool kit (STK). The proposed algorithm is applied to two operation modes: (i) telemetry, tracking, and command and (ii) payload. The results of the present study show near-optimal scheduling in both operation modes and demonstrate the applicability of the proposed algorithm to actual mission control systems.

• 한국경영과학회지
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• 제24권4호
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• pp.63-80
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• 1999

In the container transportation of inland depots the empty container is an important issue. The truck dispatching problem in this paper is considered under restriction about empty containers. When a full container arrives in a depot by truck, after unloading operation the full container is changed to an empty container. After loading operation an empty container is changed to a full container. We suggest an integrated approach to the problem of simultaneously managing empty truck and container movements. We suggest an integrated approach to the problem of simultaneously managing empty truck and container movements. We would like to find the truck dispatching method minimizing empty truck movements and empty container movements. In this paper, a mixed integer programming model is developed to obtain the optimal truck dispatching in container transportation and heuristic is developed to give a good solution in much shorter time. The numerical examples are studied and the proposed heuristic is also compared with the result of numerical examples.

• 대한수학교육학회지:학교수학
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• 제7권2호
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• pp.123-137
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• 2005

순열 조합의 문제는 내재된 의미 구조에 의해 선택, 분배, 분할의 세 가지의 유형으로 분류될 수 있다. 본 연구에서는 순열 조합의 연산과 문제 유형의 변인이 문제의 난이도에 미치는 영향을 분석하였다 그리고 문제 이해과정에서의 오류를 순서, 중복, 대상의 구별, 같은 것이 있는 순열, 상자의 구별, 분할의 조건, 기타로 분류하고 이해 단계의 장애를 구체적으로 분석하였다. 연구 결과, 순열 조합 연산과 문제의 유형은 난이도에 유의미한 영향을 미치는 것으로 나타났다. 특히 학생들에게 선택, 분할, 분배 문제간의 변환은 쉽지 않으며 순열 조합의 문제에서 학생들이 겪는 어려움 중 하나는 바로 문제 유형의 차이에서 비롯된다는 것을 알 수 있었다. 또한 현 교과서에서는 선택, 분배, 분할을 고려한 다양한 문제 유형이 부족한 것으로 나타났다. 따라서 순열 조합의 지도에 있어 문제 유형을 활용하여 다양한 의미 구조의 문제를 제시하고, 공식위주가 아닌 문제 상황을 충분히 이해하고 이에 대한 해법을 변형, 확장하는 경험을 강조하는 것이 필요하다고 하겠다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.480-483
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• 2001

Recent power quality measurement projects report that voltage sags are the most frequent disturbances in the sites [1]-[4]. DVRs were emerged as the best effective and economic solution for this problem [11]. This paper analyzed the power flow of a DVR in distribution grids. This paper showed various operation modes and boundaries such as inductive operation, capacitive operation, and minimal power operation beside the in-phase compensation.

• 한국소음진동공학회논문집
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• 제19권5호
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• pp.475-481
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• 2009

Real-coded genetic algorithm(RCGA) has better performances than conventional genetic algorithm about dealing with a large domain, the precision and the constrain problem. Also the RCGA has advantage of operation time because it doesn't have to following about decoding operation. In this paper the ranges of PID gains are limited based on Ziegler-Nichols method to consider a long operation time problem that is the main problem of genetic algorithm. Result shows proposed method represents better performance without ignored about result of ZN tuning method and reduces the calculation time.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.1746-1751
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• 2007

The bullet train runs more than 200km/h so that it is invisible to the naked eye. For this reason, KTX solely dependent on the ATC operation system. Above all things, 'stability' and 'regular time' are essential to Train Control Operation system. But intermittently, there is a signal transmission problem between ATC operation facilities and ground equipments. which is caused by wheel sliding and friction coefficient between wheel and rail when the train starts. This paper analyzed train service data for one year for accurate survey. In addition, this thesis examines the main cause of a signal transmission problem through simulation and experiment. Further, the method to solve the conventional problem is presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 C
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• pp.1123-1125
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• 1999

This paper proposes an optimization technique using Genetic Algorithm(GA) for service restoration in the distribution system. Restoration planning problem can be treated as a combinatorial optimization problem. So GA is appropriate to solve the service restoration problem in the distribution network. But searching capabilities of the GA can be enhanced by developing relevant repairing operation and modifying GA operations. In this paper, we aimed at finding appropriate open sectionalizing switch position for the restoration of distribution networks after disturbances using enhanced GA with repairing operation and modified mutation. Simulation results show that proposed method found the open sectionalizing switches with less out of service area and minimize transmission line losses and voltage drop.