• 대한전기학회:학술대회논문집
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• 대한전기학회 1990년도 하계학술대회 논문집
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• pp.171-174
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• 1990

When load areas on a feeder are deenergized due to faults,operaters need to identify nelghboring feeders, try to restore customers and minimize out-of-service areas. These cases include knowledge of system states and various constraints such as voltage drop. This paper concerns the load transfer infault restoration. Also, it is considered the operating constraints such as line current capacity, relay trip current, transformer capacity, voltage drop and line loss. The expert system is able to propose the optimal load transfer method by anallzing system states and considering constraints.

• 산업기술연구
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• 제27권A호
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• pp.69-76
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• 2007

The body of an excavator, one sort of the construction equipment, consists of mainframe part, track frame part, boom part and arm part. The all parts are manufactured in the body welding operation. The scheduling in the body welding operation of a construction equipment manufacturing is to take all the various constraints into consideration. The offset time, due date, daily capacity of operations, daily jig's capacity, precedence relation, outsourcing, alternative resource and all of the shop floor environment should be considered. An APS(Advanced Planning & Scheduling) system is a proper and efficient system in such circumstance. In this paper, we present an APS system, the optimal scheduling system for the construction equipment manufacturing specifically for the body welding operation, using ILOG Solver/Scheduler. ILOG Solver/Scheduler is a general purposed commercial software which supports to find a feasible or optimal solution using object oriented technique and constraints satisfaction programming, given constraints and objectives.

• 환경영향평가
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• 제12권3호
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• pp.151-160
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• 2003

Analysis of carrying capacity and site suitability by the systematic application of environmental information an provide a basis for implementing environmentally sensitive and sustainable resource development policies. Based on the availability of public services and environmental and site-specific constraints, a Rural Residential Density Matrix was applied in Santa Cruz County, California, USA to assess the development potential of rural land parcels since 1980. In one case, the Matrix was applied to calculate the allowable development density on a site in Lompico planned for use as a Buddhist retreat center. These calculations revealed higher environmental sensitivity and lower carrying capacity than projected in the proposed plan. Under the constraints of the county's minimum acreage policies and insufficient developable land, the developer cancelled the proposed plan. This example suggests that application of the Matrix at the concept development stage would increase the effectiveness of the prior environmental review and environmental impact assessment (EIA) system in Korea.

• 산업기술연구
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• 제16권
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• pp.217-230
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• 1996

This paper deals with storage and retrieval policies for S/R machine with capacity constraints in Man-On-Board AS/RS. It is assumed that storage sequence is based on SFC(spacefilling curve) routine and that storage layout is dedicated by storage policies. We present several heuristic algorithms for storage and retrieval policies which minimize total distance travelled by the S/R machine. These algorithms are based on COI, group COI, frequency of order, similarity between items and capacity of S/R machine. Experimental results of 24 combinastorial policies are provided to illustrate the performance of the heuristics under various rack utilization ratios. In storage policies, the results show that algorithms considering both similarity and frequency are better than those with COI as rack utilization is increasing. And algorithm using group COI is superior to others. In retrieval policies, the method with revision expression is shown to be better than others.

• 대한산업공학회지
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• 제33권3호
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• pp.303-311
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• 2007

This study deals with a type of vehicle routing problem faced by manager of some department stores during peak sales periods. The problem is to find a set of traveling paths of vehicles that leave a department store and arrive at a destination specified for each vehicle after visiting customers without violating time and capacity constraints. The mathematical model is formulated with the objective of maximizing the sum of the rewards collected by each vehicle. Since the problem is known to be NP-hard, a heuristic algorithm is developed to find the solution. The performance of the algorithm is compared with the optimum solutions obtained from CPLEX for small size problems and a priority-based Genetic Algorithm for large size problems.

• 대한전자공학회논문지TC
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• 제49권8호
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• pp.70-76
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• 2012

본 논문에서는 TV 화이트 스페이스(TV white space, TVWS)에서 OFDM(orthogonal frequency division multiplexing) 기반 비인가 사용자의 파워 할당 기법을 제안한다. 비인가 사용자는 TVWS를 사용할 때, 시간 도메인에서 TVWS의 파워 제약조건을 충족시키기 위해 전송 파워를 조절해야 한다. TDM(time division multiplexing) 혹은 FDM (frequency division multiplexing)과 달리 OFDM은 시간 도메인에서 높은 PAPR(peak-to-average power ratio)을 가지기 때문에, 기존의 비인가 사용자의 파워 할당 기법이 TVWS에 적용될 경우 TVWS의 파워 제약 조건을 충족시킬 수 없게 된다. 그러므로 본 논문에서는 OFDM의 높은 PAPR값을 제어하여 순시적으로 TVWS의 파워 제약 조건을 만족시킬 수 있는 새로운 파워 할당 기법을 제안한다. 또한, 이를 기반으로 OFDM 기반 비인가 사용자의 용량을 닫힌 형태(closed form)로 분석한다. 이에 따르면, 부반송파의 개수를 줄일수록 용량을 향상시킬 수 있다. 모의실험을 통해서, 비인가 사용자의 용량은 부반송파 개수가 작아질수록, 비인가 사용자의 송신단-수신단 간 채널 평균값이 커질수록 증가하는 것을 보여준다.

• 한국통신학회:학술대회논문집
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• 한국통신학회 1983년도 추계학술발표회논문집
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• pp.108-111
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• 1983

This paper presents a new method for the optimum capacity assignment in store-and-forward communication networks under a total fixed-capacity constraints. Any two link capacities needed in this method can have the desirable quantites and then other capacities can be obtained from the fixed two link capacities. When the minimum and the maximum capacities that are the quantites of the conventional method are fixed, the total average time delay from the new method is almost the same as that from the conventional method. And when the minimum capacity is fixed, the new method gives smaller average time delay.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1996년도 춘계공동학술대회논문집; 공군사관학교, 청주; 26-27 Apr. 1996
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• pp.289-289
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• 1996

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2018년도 춘계학술논문요약집
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• pp.92-93
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• 2018

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권9호
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• pp.2154-2172
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• 2013

A centralized cognitive radio (CR) network is proposed and its system capacity is studied. The CR network is designed with power control and multi-user scheduling schemes to support best-effort traffics under peak interference power constraints. We provide an analytical framework to quantify its system capacity, taking into account various key factors such as interference constraints, density of primary users, cell radius, the number of CR users, and propagations effects. Furthermore, closed-form formulas are derived for its capacities when only path loss is considered in the channel model. Semi-analytical expressions for the capacities are also given when more realistic channel models that include path loss, shadowing, and small-scale fading are used. The accuracy of the proposed analytical framework is validated by Monte Carlo simulations. Illustrated with a practical example, the provided analytical framework is shown to be useful for the strategic planning of centralized CR networks.