• Journal of the Society of Naval Architects of Korea
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• v.39 no.4
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• pp.60-65
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• 2002

In order to generate hull form, we introduced optimization process. Fairness criteria is applied to object function, B-Spline control vertices are considered as design variables, optimization is proceeded with satisfying geometric constraint conditions. GA(Genetic Algorithm) and optimality criteria are applied to optimization process in this study.

• Korean Journal of Construction Engineering and Management
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• v.20 no.5
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• pp.42-51
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• 2019

The train operation institution establishes a transportation plan based on the forecast of transport demand and the ability of train vehicles to transport, and establishes a train operation plan accordingly. The train operation plan adjusts the intervals between trains, creates a timetable (train diagram) for trains, and establishes a plan for the operation of train vehicles used for train operation. The train operation institution shall establish a crew schedule to determine and place the crew members of the trains arranged in the diagram in order to enhance the efficiency of the operation management of the trains. In this study, the authors apply the neighborhood search method that satisfies the constraints at the phase of generating the crew diagram. This suggests a methodology for efficient management of crew schedule plan. The crew diagram generated in this study compared with the existing crew diagram in accordance with the actual operating train timetable, and verified the effectiveness of the suggested method.

• International Commerce and Information Review
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• v.19 no.1
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• pp.213-234
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• 2017

This study analyzed valid samples of 707 units collected by conducting paper and online surveys on the Korean, the Chinese, the American, and the Japanese. The result showed that a significant causal relationship exists between power distance and pull motivation as well as collectivism and push motivation, which led to a conclusion that developing travel packages that can strengthen bonding of fraternal societies through various events and attractions is effective for respondents from Asian countries. On the other hand, Americans turned out to prefer practical plans, which could provide individual's needs and preferences, for example, a self-healing package. This study, using a simple survey, may have a limitation in that it does not allow the participants to express their opinions. However, the study is meaningful that it made a theoretical contribution utilizing Hofstede's cultural dimensions index, two types of motivation, and theories of customer satisfaction and revisit intention. It also has a practical implication in that it proposes the most optimal and applicable overseas travel marketing strategy by comparing cultural traits of each country.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.6
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• pp.40-53
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• 2018

In smart card data, movement of railway passengers appears in order of smart card terminal ID. The initial terminal ID holds information on the entering station's tag-in railway line, the final terminal ID the exit station tag-out railway line, and the middle terminal ID the transfer station tag subway line. During the past, when the metropolitan city rail consisted of three public corporations (Seoul Metro, Incheon Transit Corporation, and Korail), OD data was expressed in two metrics of initial and final smart card terminal ID. Recently, with the entrance of private corporations like Shinbundang Railroad Corporation, and UI Corporation, inclusion of entering transfer line terminal ID and exiting transfer line terminal ID as part of Chain OD has become standard. Exact route construction using Chain OD has thus become integral as basic data for revenue allocation amongst metropolitan railway transport corporations. Accordingly, path detection in railway networks has evolved to an optimal path detection problem using Chain OD, hence calling for a renewed solution method. This research proposes an optimal path detection method between the initial terminal ID and final terminal ID of Chain OD terminal IDs within the railway network. Here, private line transfer TagIn/Out must be reflected in optimal path detection using Chain OD. To achieve this, three types of link-based optimum path detection methods are applied in order of 1. node-link, 2. link-link, 3. link-node. The method proposed based on additional path costs is shown to satisfy the optimal conditions.

• Journal of KIISE:Computing Practices and Letters
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• v.6 no.2
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• pp.216-224
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• 2000

The spatial layout planning system allocates rectangular resources in the limited space according to user requirements, This system also can optimizes the spatial allocation problem to maximize the user's requirement. The spatial layout planning Problems for this system can be solved by searching a wide area of space since this problem entails the non-polynomial algorithm. By accommodating the user's dynamic requirements, the modification of a specific space and the redesign of the whole area can be accomplished. In this paper, the spatial layout planning problem is solved efficiently with a resource allocation method based on CSP. The dynamic constraints by adding user requirements are accommodated through the intelligent user Interface. The 3-D layout on the web environment by using VRML is also shown for providing for the visual verification of the 2-D layout and, thereafter, the additional modification of the 2-D layout.

• Journal of the Korea Society of Computer and Information
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• v.13 no.5
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• pp.219-227
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• 2008

As found in research on constraint satisfaction problems, the choice of variable ordering heuristics is crucial for effective solving of constraint optimization problems. For the special problems such as energy-efficient clustering in heterogeneous wireless sensor networks, in which cluster heads have an inclination to be near a base station, we propose a new approach based on the static preferences variable orderings and provide a pnode heuristic algorithm for a specific application. The pnode algorithm selects the next variable with the highest Preference. In our problem, the preference becomes higher when the cluster heads are closer to the optimal region, which can be obtained a Priori due to the characteristic of the problem. Since cluster heads are the most dominant sources of Power consumption in the cluster-based sensor networks, we seek to minimize energy consumption by minimizing the maximum energy dissipation at each cluster heads as well as sensor nodes. Simulation results indicate that the proposed approach is more efficient than other methods for solving constraint optimization problems with static preferences.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.8
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• pp.656-661
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• 2013

In Guided Scrambling (GS) encoding for the holographic storage, after scrambling augmented source word into codeword, the best codeword satisfying modulation constraint is determined. Modulation constraints considered in this paper are strength which is the minimum number of transition between '0' and '1' in each row and column of codeword array and the symbol balancedness of codeword array. In this paper, we show that GS encoding procedure can be formulated as an integer programming model and develop a fast neighborhood search heuristic for fast computation of control bits. In the simulation, we compared the performance of heuristic algorithm with the integer programming model for various array and control bit size combinations.

• Journal of Korea Society of Industrial Information Systems
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• v.4 no.2
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• pp.44-50
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• 1999

This paper presents a set of techniques to automatically find rate optimal or near rate optimal implementation of shift-invariant flow graphs on pipelined processor, in which pipeline processor has multiple accumulators and internal datapaths. In such case, the problem to be addressed is the scheduling of multiple instruction streams which control all of the pipeline stages. The goal of an automatic scheduler in this context is to rearrange the order of instructions such that they are executed with minimum iteration period between successive iteration of defining flow graphs. The scheduling algorithm described in this paper also focuses on the problem of removing the hazards due to inter-instruction dependencies.

• Journal of Navigation and Port Research
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• v.31 no.10
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• pp.869-877
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• 2007

This paper proposes a realtime scheduling method using local search algorithm for non-crossable yard cranes in automated container terminal. To take into consideration the dynamic property of yard crane operation and satisfy the real time constraint, the proposed method repeatedly builds crane schedule for the jobs in a fixed length look-ahead horizon whenever a new job is requested In addition, the proposed method enables the co-operation between yard cranes through prior re-handling and re-positioning in order to resolve the workload imbalance problem between the two cranes, which is one of the primary causes that lower the performance of yard cranes. Simulation-based experiments have shown that the proposed method outperforms the heuristic based methods, and the cooperation scheme contributes a lot to the performance improvement.

• Journal of the Korean Society of Hazard Mitigation
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• v.6 no.2 s.21
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• pp.51-60
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• 2006

The objective of this research is to develop a least cost system design method for branched storm sewer systems while satisfying all the design constraints using heuristic techniques such as genetic algorithm and harmony search. Two sewer system models have been developed in this study. The SEWERGA and SEWERHS both determine the optimal discrete pipe installation depths as decision variables. Two models also determine the optimal diameter of sewer pipes using the discrete installation depths of the pipes while satisfying the discharge and velocity requirement constraints at each pipe. Two models are applied to the example that was originally solved by Mays and Yen (1975) using their dynamic programming(DP). The optimal costs obtained from SEWERGA and SEWERHS are about 4% lower than that of the DP approach.