• 전기학회논문지
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• 제58권11호
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• pp.2136-2141
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• 2009

Transmission planning is an important part of power system planning to meet an increasing demand for electricity. The objective of transmission expansion is to minimize operational and construction costs subject to system constraints. There is inherent uncertainty in transmission planning due to errors in forecasted demand and fuel costs. Therefore, transmission planning process is not reliable if the uncertainty is not taken into account. The paper presents a systematic method to find the optimal location and amount of transmission expansion using Cross-Entropy (CE) incorporating uncertainties about future power system conditions. Numerical results are presented to demonstrate the performance of the proposed method.

• 한국수자원학회논문집
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• 제43권5호
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• pp.495-505
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• 2010

유역단위의 통합적 치수계획은 고려되는 단위사업의 수가 많고 그 특성도 다양하므로 이들을 조합한 최적의 대안을 수립하기가 쉽지 않다. 최적의 대안수립을 위해서는 홍수피해를 산정하는 것뿐만 아니라 감내할 수 있는 피해의 수준을 결정해야만 한다. 이에 대한 결정은 큰 틀에서 '사회적 합의'라는 방식으로 도출되지만 일차적으로는 기술적으로 가능한 범주에서 경제적 효율성 측면의 분석을 필요로 한다. 본 연구의 목적은 각 단위사업들의 조합이 경제적 효율성을 갖도록 하는 대안수립 방법을 제시하는 것이다. 이를 위해서 치수사업을 투입과 산출에 의한 경제학적 생산활동으로 정의하고 최적사업규모를 대안수립의 원칙으로 제시하였다. 본 연구는 기존에 공학적 측면에만 의존하던 대안수립 방법을 개선하여 경제적 측면에서 최적사업규모를 고려하였다는 데에 의의가 있다. 이러한 대안수립 방법은 하천중심의 소극적 치수계획을 지양하고 피해지역 중심의 유역단위 치수계획 수립으로 전환되고 있는 최근의 정부정책 방향에도 부합하며, 정책수립을 위한 효과적인 수단을 제공할 수 있을 것으로 기대된다.

• 한국측량학회지
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• 제35권4호
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• pp.281-290
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• 2017

Transportation plays a vital role in sustainable development, and moreover, bulk transportation provides cost effective movement of goods and human beings with less environmental issues. Nepal is a developing country with increasing urbanization and transportation demands. The growing interest of China to connect with Southeast Asia through Nepal has led to ambitious project proposal of Rasuwa Gadhi to Birgunj Railways, which is the shortest route from China to India. Lack of updated geospatial data has lead the concerned authorities in Nepal to be dependent on analysis and proposals from donor nations. Taking such considerations, based on GIS and free data, this study explores optimal routes to connect cites using slope and land cover. Based on reclassified slope, two shortest optimal routes were found. One passing through Baireni in Dhading and another through Kathmandu towards Birgunj with length of around 172 Kilometers. The study shows that available open source data can be used of preliminary feasibility studies and yet shows limitations for detailed economy based planning. Development and use of high resolution updated geospatial data is of high necessity for Nepal to become self-sustained in planning of development works.

• 한국해양공학회지
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• 제20권1호
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• pp.69-76
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• 2006

The design of efficient search path to maximize the Cumulative Detection Probability(CDP) is mainly dependent on experience and intuition when searcher detect the target using SONAR in the ocean. Recently with the advance of modeling and simulation method, it has been possible to access the optimization problems more systematically. In this paper, a method for the optimal search path calculation is developed based on the combination of the genetic algorithm and the calculation algorithm for detection range. We consider the discrete system for search path, space, and time, and use the movement direction of the SONAR for the gene of the genetic algorithm. The developed algorithm, OASPP(Optimal Acoustic Search Path Planning), is shown to be effective, via a simulation, finding the optimal search path for the case when the intuitive solution exists. Also, OASPP is compared with other algorithms for the measure of efficiency to maximize CDP.

• Journal of Biosystems Engineering
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• 제33권1호
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• pp.51-57
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• 2008

The purpose of this study was to develop an optimal path planning program for autonomous speed sprayer in orchard. A digital map which contained coordinate information and entity information including height, width, radius of main stem, and disease of a trees was developed to build an optimal path. The digital map, dynamic programming and order-picking algorithm were used for planning an optimal path for autonomous speed sprayers. When this algorithm applied to rectangular-shaped orchards to travel whole trees, the developed program planned the same working path and same traveling distance as those of created by conventional method. But for irregular-shaped orchards, developed program planned differently and 5.06% shorter path than conventional method. When applied to create path for multi-selected trees, irregular-shaped orchards showed 13.9% shorter path and also rectangular-shaped orchards showed 9.1% shorter path. The developed program always planned shorter path than the path created by conventional method despite of variation of shape of orchards.

• Steel and Composite Structures
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• 제15권5호
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• pp.519-538
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• 2013

The design optimization of a cold-formed steel portal frame building is considered in this paper. The proposed genetic algorithm (GA) optimizer considers both topology (i.e., frame spacing and pitch) and cross-sectional sizes of the main structural members as the decision variables. Previous GAs in the literature were characterized by poor convergence, including slow progress, that usually results in excessive computation times and/or frequent failure to achieve an optimal or near-optimal solution. This is the main issue addressed in this paper. In an effort to improve the performance of the conventional GA, a niching strategy is presented that is shown to be an effective means of enhancing the dissimilarity of the solutions in each generation of the GA. Thus, population diversity is maintained and premature convergence is reduced significantly. Through benchmark examples, it is shown that the efficient GA proposed generates optimal solutions more consistently. A parametric study was carried out, and the results included. They show significant variation in the optimal topology in terms of pitch and frame spacing for a range of typical column heights. They also show that the optimized design achieved large savings based on the cost of the main structural elements; the inclusion of knee braces at the eaves yield further savings in cost, that are significant.

• Journal of Electrical Engineering and Technology
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• 제9권4호
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• pp.1163-1170
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• 2014

Due to global environmental regulations and policies with rapid advancement of renewable energy technologies, the development type of renewable energy sources (RES) in power systems is expanding from small-scale distributed generation to large-scale grid-connected systems. In the near future, it is expected that RES achieves grid parity which means the equilibrium point where the power cost of RES is equal to the power costs of conventional generators. However, although RES would achieve the grid parity, the cost related with development of large-scale RES is still a big burden. Furthermore, it is hard to determine a suitable capacity of RES because of their output characteristics affected by locations and weather effects. Therefore, to determine an optimal capacity for RES becomes an important decision-making problem. This study proposes a method for determining an optimal installed capacity of RES from the business viewpoint of an independent power plant (IPP). In order to verify the proposed method, we have performed case studies on real power system in Incheon and Shiheung areas, South Korea.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2023년도 춘계학술대회
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• pp.160-161
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• 2023

현재 선박의 항해계획은 항해사의 지식과 경험적인 방법에 의존하고 있다. 그러나 최근에는 선박 자율운항기술이 발전됨에 따라, 항해계획의 자동화 기술도 여러 가지 방법으로 연구되고 있다. 본 연구에서는 강화학습 기법 중 하나인 Q-러닝을 기반으로 선박 최적 항해 경로를 생성하고자 한다. 강화학습은 다양한 상황에 대한 경험을 학습하고, 이를 기반으로 최적의 결정을 내리는 방식으로 적용된다.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 1989년도 추계학술발표회 발표논문초록집; 이화여자대학교, 서울; 23 Sep. 1989
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• pp.58-58
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• 1989

• 대한조선학회논문집
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• 제56권6호
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• pp.480-487
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• 2019

Ship route planning is to find a route to minimize voyage time and/or fuel consumption in a given sea state. Unlike previous studies, this study proposes an optimization method for the route planning to avoid the grounding risk near the coast. The route waypoints were searched using A^* algorithm, and the route simplification was performed to remove redundant waypoints using Douglas-Peucker algorithm. The optimization was performed to minimize fuel consumption by setting the optimization design parameters to the engine rpm. The sea state factors such as wind, wave, and current are also considered for route planning. We propose the constraint to avoid ground risk by using under keel clearance obtained from electoronic navigational chart. The proposed method was applied to find the optimal route between Mokpo and Jeju. The result showed that the proposed method suggests the optimal route that minimizes fuel consumption.