• 한국컴퓨터정보학회논문지
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• 제20권10호
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• pp.77-83
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• 2015

This paper suggests heuristic algorithm to obtain optimal solution of minimum number of delay aircraft in airport arrivals/departures problem. This problem can be solved only mathematical optimization method. The proposed algorithm selects the minimum delays capacity in various airport capacities for number of arrivals/departures aircraft in $i^{th}$ time interval (15 minutes). In details, we apply median selection method and left-right selection method. This algorithm can be get the optimal solution of minimum number of delay aircraft for sixes actual experimental data.

• 한국도로학회논문집
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• 제15권6호
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• pp.125-133
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• 2013

PURPOSES : The purpose of this study is to propose delay-minimizing operation methodology of a signalized intersection based upon optimization of lane-uses on approaching lanes for an intersection. METHODS : For the optimization model of lane-uses, a set of constraints are set up to ensure feasibility and safety of the lane-uses, traffic flow, and signal settings. Minimization of demand to saturation flow ratio of a dual-ring signal control system is introduced to the objective function for delay minimization and effective signal operation. Using the optimized lane-uses, signal timings are optimized by delay-based model of TRANSYT-7F. RESULTS : It was found that the proposed objective function is great relation with delay time for an intersection. From the experimental results, the method was approved to be effective in reducing delay time. Especially, cases for two left-turn lanes reduced greater delays than those for a left turn lane. It is noticed that the cases for different traffic volume by approach reduced greater delays than those for the same traffic volume by approach. CONCLUSIONS : It was concluded that the objective function is proper for lane-uses optimizing model and the operation method is effective in reducing delay time for signalized intersections.

• 전자공학회논문지A
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• 제32A권2호
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• pp.140-150
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• 1995

A symbolic layout generator, called Flexible Module Generator (FMG), has been developed for transgorming a given CMOS circuit netlist into an optimized symbolic layout. Contrary to other conventional module generators which place transistors either in horizontal or in vertical direction, FMG places transittors in any hence can multiples of 90$^{\circ}$. This flexible layout style can maximize the diffusion sharing and hence can reduce the wire-length for both of area minimization and performance improvement. In FMG, transistors are initially randomly placed and then selected transistors are iteratively replaced using an optimization technique based on simulated evolution. Whenever a transistor is replaced, the affected nets are rerouted. Constraints on the shape, aspect ratio, and critical path delays are considered during the optimization process. Routing is performed by using a modified maze router on polysilicon, metal 1, and metal 2 interconnection layers. additional routing grids are added, if necessary, for complete routing. Unused rows or columns are removed after routing for area minimization. Experimental reasults show that FMG synthesizes satisfactory layouts.

• 한국경영과학회지
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• 제26권2호
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• pp.1-11
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• 2001

This paper considers the scheduling of cell-based handoffs to balance the traffic in a fiber-optic microcelluar system. In the system depending on the order of cell based handoff, periodical balancing of the traffic among microcells can be achieved. The cell based handoff problem is formulated as a dynamic programming and the computational complexity is analyzed. Since the scheduling problem requires real time solution, heuristic algorithms are proposed and the computational results are discussed.

• 한국인터넷방송통신학회논문지
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• 제16권1호
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• pp.245-251
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• 2016

본 논문은 다중공항의 도착/출발 문제에 대해 항공기 지연을 최소화시키는 최적 해를 얻을 수 있는 휴리스틱 알고리즘을 제안하였다. 단일 공항의 출발/도착 항공기의 지연 대수를 최소화시키는 최적 해를 찾는 문제에 대해 수학적 방법만이 제안되고 있다. 다중공항의 경우는 선형계획법이나 메타휴리스틱 방법의 일종인 유전자 알고리즘이 적용되고 있다. 제안된 알고리즘은 먼저, 각 공항의 i번째 단위시간 (15분)에서 총 도착/출발 항공기 대수에 대해 지연을 최소화시키는 운영 능력들 중 중앙값을 선택하였다. 다음으로 공항간 도착 항공기의 도착지를 변경시켰다. 실험 결과 제안된 알고리즘은 유전자 알고리즘에 비해 지연 항공기 대수에 대해 보다 좋은 결과를 얻었다.

• Management Science and Financial Engineering
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• 제5권1호
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• pp.1-25
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• 1999

There is a worldwide trend to automate the handling operations in port container terminals in an effort to improve productivity and reduce labor cost. This study iscusses how to apply an AGV(automated guided vehicle) system to the handling of containers in the yard of a port container ter-minal. The main issue of this paper is how to assign tasks of container delivery to AGVs during ship operations in an automated port container terminal. A dual-cycle operation is assumed in which the loading and the discharging operation can be performed alternately. Mixed integer linear program-ming formulations are suggested for the dispatching problem. The completion time of all the dis-charging and loading operations by a quayside crane is minimized, and the minimization of the total travel time of AGVs is also considered as a secondary objective. A heuristic method using useful properties of the dispatching problem is suggested to reduce the computational time. The perfor-mance of the heuristic algorithm is evaluated in light of solution quality and computation time.

• 한국통신학회논문지
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• 제38B권2호
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• pp.115-121
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• 2013

LED-ID (Light Emitting Diode-Identification) network is envisioned to be the next generation indoor wireless communication medium by which simultaneously high speed data transmission, identification, and illumination are possible. In spite of being extremely promising, it suffers from much impairment. Signals having different propagation paths can suffer from delays, and phase shifts which will eventually result interference. The probability of interference is also increased when communication links are established between a tag and several readers. Therefore it is necessary to reduce the interference in LED-ID network to ensure quality of service. It is possible to avoid interference by knowing the information about readers prior to assign the available spectrum. In this paper, we have proposed dynamic spectrum decision using cognitive radio concept. The simulation results justify that the proposed scheme is better than the conventional scheme.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.1466-1472
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• 2008

To minimize the train operation interruptions and train exchanges, the RF transmission system is proposed. The current control room of the Seoul Metro has information of the train movement through the Total Traffic Control System, but it does not have information of the train itself, rail status, and other facilities' status. When some trouble occurs during train operation, the train crews should report the control room about the trouble and fix it. If the control room has exact information of the trouble, the expert in the control room can help the crews to fix the trouble swiftly and exactly. Since the crews are busy taking care of the trouble, they often miss to report the control room on time. The proposed RF transmission system relays the information of the train to the control room automatically in real time, and makes it possible to provide the passengers good service by reducing the train operation interruptions and train exchanges.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
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• pp.558-560
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• 1994

In this paper, a memoryless H$_{\infty}$ controller for linear systems with state and input delays is presented. The proposed controller is a delay independent stabilizer which reduces the H$_{\infty}$ norm of the closed loop transfer function, from the disturbance to the controlled output, to a precribed level. The controller is obtained by solving a minimization problem involving linear matrix inequalities.s.

• 산업융합연구
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• 제16권1호
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• pp.21-26
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• 2018

해상을 통한 물동량이 전체 97% 차지하고 있어 효율적인 항만 운영 관리 시스템을 통해 작업효율을 높이는 동시에 운영비용을 절감하고, 관리자가 작업 지연 및 장비 지원이 필요한 상황이 발생한 경우 신속하게 이를 확인하여 대처할 필요가 있다. 기존 시스템은 GPS 을 이용한 야드 자동화 장비의 실시간 위치정보 확인을 토대로 작업 완료 혹은 작업 시작에 따라 입력된 정보로 위치 정보를 모니터링하고 있다. 기존 시스템보다 태블릿의 GPS 시스템으로 실시간 위치정보 확인 시스템이 야드 조업 장비의 위치 확인에 있어 더욱 정확한 정보 제공이 가능하다. 야드장 내의 통신망에서도 컨테이너로 인한 음영이 없는 상용 LTE 서비스를 활용한 망 구성이 컨테이너 처리 지연을 줄인다. 마지막으로 안드로이드나 IOS를 사용하는 스마트단말기의 도입과 인공지능을 활용한 컨테이너 처리 스케줄링을 통해 컨테이너 처리 어플리케이션의 스마트 단말 사용과 컨테이너 작업 스케줄의 최적화를 통한 최소 지연시스템을 구축한다. 스마트 단말의 도입과 인공지능을 활용한 컨테이너 처리 지연의 최소화는 컨테이너 정보 요구자인 소비자에게 실시간으로 컨테이너의 처리과정을 확인시킴으로써 항만 서비스의 질적 향상이 예상된다.