• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.11
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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.

• Journal of Korea Water Resources Association
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• v.43 no.5
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• pp.495-505
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• 2010

The integrated basin-wide flood mitigation planning has a numerous individual proposals with different characteristics. So, it makes difficult to develop the optimal alternative that combines such elements. To develop the optimal alternative, it's necessary not only to assess the flood damage but also to define a tolerable degree of damage. Such a definition is made in a way, dubbed the 'social consensus' in a broad sense; but initially, it requires the analysis of the economic efficiency within a scope, which is technically achievable. This study aims to propose the alternatives development method so that the combination of the individual proposals could be economically efficient. To this end, this study defined the flood mitigation projects as the economic production activities carried out by inputs and outputs, and proposed the optimal project size as the principle of developing alternatives. This study may have the worth in improving the alternatives development method by considering the optimal project scale from the economic viewpoint while the existing method depending on engineering aspect. Such approach is expected to correspond to the current government's policy that avoids the passive flood mitigation focused on channel-wide planning but pursues the basin-wide flood mitigation planning focusing on damaged area, thereby provide efficient tools to come up with the solution.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.35 no.4
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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.

• Journal of Ocean Engineering and Technology
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• v.20 no.1 s.68
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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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• v.33 no.1
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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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• v.15 no.5
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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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• v.9 no.4
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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.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.05a
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• pp.160-161
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• 2023

Currently, the ship's passage planning relies on the navigator officer's knowledge and empirical methods. However, as ship autonomous navigation technology has recently developed, automation technology for passage planning has been studied in various ways. In this study, we intend to generate an optimal route for a ship based on Q-learning, one of the reinforcement learning techniques. Reinforcement learning is applied in a way that trains experiences for various situations and makes optimal decisions based on them.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1989.10a
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• pp.58-58
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• 1989

• Journal of the Society of Naval Architects of Korea
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• v.56 no.6
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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.