• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.2
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• pp.178-188
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• 2019

When using a distributed system, it is very important to know the intention of a target ship in order to prevent collisions. The action taken by a certain ship for collision avoidance and the action of the target ship it intends to avoid influence each other. However, it is difficult to establish a collision avoidance plan in consideration of multiple-ship situations for this reason. To solve this problem, a Distributed Stochastic Search Algorithm (DSSA) has been proposed. A DSSA searches for a course that can most reduce cost through repeated information exchange with target ships, and then indicates whether the current course should be maintained or a new course should be chosen according to probability and constraints. However, it has not been proven how the parameters used in DSSA affect collision avoidance actions. Therefore, in this paper, I have investigated the effect of the parameters and weight factors of DSSA. Experiments were conducted by combining parameters (time window, safe domain, detection range) and weight factors for encounters of two ships in head-on, crossing, and overtaking situations. A total of 24,000 experiments were conducted: 8,000 iterations for each situation. As a result, no collision occurred in any experiment conducted using DSSA. Costs have been shown to increase if a ship gives a large weight to its destination, i.e., takes selfish behavior. The more lasting the expected position of the target ship, the smaller the sailing distance and the number of message exchanges. The larger the detection range, the safer the interaction.

• Journal of Korean Medicine Rehabilitation
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• v.20 no.2
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• pp.63-77
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• 2010

Objectives : It is known that abdominal obesity increases the possibility of cardiovascular diseases, early death, and metabolic syndrome including dyslipidemia and insulin resistance. Clinical trials have been under way to verify the effectiveness of treatment for abdominal obesity. The objective of this study is to set criteria about how effective oriental medicine and acupuncture are in abdominal obesity. Methods : I manually search "www.clinicaltrial.gov", 4 Korean medical databases and 4 Korean medical journals of abdominal obesity. Search terms used were "abdominal obesity" or "visceral obesity". In order to see detail review, searching was performed from 01, 01, 2005 to 11, 31, 2009. And I classified all the searched studies into design, intervention, purpose, end point, diseases, condition and etc. Results : 1. I could search total 67 trials in "www.clinicaltrial.gov". I found 9, 10, 13, 8, 6 clinical trial from 2005 to 2009 every year. 2. Test on both gender and adult or adult and senior have been most frequent. 3. Randomization clinical trial is 51 cases that occupied 96.2%. 38 cases use control group. 4. Body mass index(BMI) and waist circunference(WC) are major criteria of abdominal obesity clincal trial. WC, BMI, abdominal fat mass, body weight are measured at end point of abdominal obesity clincal trial. 5. I could search total 86 cases in domestic study. I found 15, 23, 23, 20, 5 cases from 2005 to 2009 every year. 6. Test on female and adult have been most frequent in domestic study. 7. Randomization clincal trial is only 2 cases that occupied 2.3%. 62 cases use control group in domestic study. 8. BMI, body fat percent, WC, visceral-subcutaneous fat ratio(VSR), waist-hip ratio(WHR) are criteria of abdominal obesity clincal trial in domestic study. WC, BMI, abdominal fat mass, body weight are measured at end point of abdominal obesity clincal trial in domestic study. Conclusions : To improve abdominal obesity study in traditional korean medicine, it is need to activate clinical trial, meta analysis, develope of clinical practice guidelines, co-works with conventional medicine and etc.

• Journal of the Korean Society for information Management
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• v.29 no.4
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• pp.101-121
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• 2012

Since IR systems which adopt only Boolean IR model can not provide ranked search result, users have to conduct time-consuming checking process for huge result sets one by one. This study proposes a method to provide search results ranked by using coupling information between tags instead of index weight information in Boolean IR model. Because document queries are used instead of general user queries in the proposed method, key tags used as queries in a relevant document are extracted. A variety of groups of Boolean queries based on tag couplings are created in the process of extracting queries. Ranked search result can be extracted through the process of matching conducted with differential information among the query groups and tag significance information. To prove the usability of the proposed method, the experiment was conducted to find research trend analysis information on selected research information. Aslo, the service based on the proposed methods was provided to get user feedback for a year. The result showed high user satisfaction.

• The KIPS Transactions:PartB
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• v.16B no.4
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• pp.319-326
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• 2009

PSO(Particle Swarm Optimization) is an optimization algorithm in which simple particles search an optimal solution using shared information acquired through their own experiences. PSO applications are so numerous and diverse. Lots of researches have been made mainly on the parameter settings, topology, particle's movement in order to achieve fast convergence to proper regions of search space for optimization. In standard PSO, since each particle uses only information of its and best neighbor, swarm does not explore diverse regions and intended to premature to local optima. In this paper, we propose a new particle's movement strategy in order to explore diverse regions of search space. The strategy is that each particle moves according to relative weights of several better neighbors. The strategy of exploring diverse regions is effective and produces less local optimizations and accelerating of the optimization speed and higher success rates than standard PSO. Also, in order to raise success rates, we propose a strategy for checking whether swarm falls into local optimum. The new PSO algorithm with these two strategies shows the improvement in the search speed and success rate in the test of benchmark functions.

• Journal of Korea Multimedia Society
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• v.12 no.9
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• pp.1333-1341
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• 2009

Tactical path-finding in computer games is path-finding where a path is selected by considering not only basic elements such as the shortest distance or the minimum time spend but also tactical information of surroundings when deciding character's moving trajectory. One way to include tactical information in path-finding is to represent a heuristic function as a sum of tactical quality multiplied by a weighting factor which is.. determined based on the degree of its importance. The choice of weighting factors for tactics is very important because it controls search performance and the characteristic of paths found. In this paper. we propose a method for improving a heuristic function by adjusting weights based on the difference between paths on examples given by a level designer and paths found during the search process based on the CUITent weighting factors. The proposed method includes the search algorithm modified to detect search errors and learn heuristics and the perceptron-like weight updating formular. Through simulations it is demonstrated how different paths found by tactical path-finding are from those by traditional path-finding. We analyze the factors that affect the performance of learning and show the example applied to the real game environments.

• Architectural research
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• v.15 no.4
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• pp.207-214
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• 2013

A form-finding technique is proposed for three-dimensional spatial structures. Two-step discrete finite element (FE) mesh generator based on computer aided geometric design (CAGD) is introduced and used to control the shape of three-dimensional spatial structures. Mathematical programming technique is adopted to search new forms (or shapes) of spatial structures. For this purpose, the strain energy is introduced as the objective function to be minimized and the initial volume (or the initial weight) is considered as constraint function. Numerical examples are carried out to test the capability of the proposed form-finding techniques and provided as benchmark tests.

• Journal of Korean Society for Quality Management
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• v.12 no.2
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• pp.33-36
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• 1984

This paper is concerned with the optimal replacement policy of auto-scale with increasing error-variance. This optimization model is to minimize the sum of the cost of defective and excess weight allowance for a target value. The numerical example for the proposed problem is solved by Golden-Section Search and Simpsons's rule.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.9
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• pp.1600-1604
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• 2010

This paper presents the optimum design of the brushless motor to maximize the output power per weight considering the design parameter tolerance. The optimization is proceeded by commercial software that is adopted the scatter-search algorithm and the characteristic analysis is conducted by FEM. The stochastic optimum design results are compared with those of the deterministic optimization method. We can verify that the results of the stochastic optimization is superior than that of deterministic optimization.

• Bulletin of the Society of Naval Architects of Korea
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• v.17 no.4
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• pp.46-54
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• 1980

The ship structural design problem is formulated as a general nonlinear optimization problem with constraints. Characteristics of the general structural problems and various optimization techniques are discussed, with special emphasis on penalty function method for constrained problems. A simple example of the solution of a midship structure design of cargo vessel, which complies with the rules of the Korean Register of Shipping is shown using SUMT-exterior method with some search methods.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04b
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• pp.340-342
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• 2004

Promsearch는 인간 DNA에서 코어 프로모터 영역을 예측하는 프로그램이며, PWM(position weight matrix)과 신경망을 기반으로 전사시작지점을 예측한다. 프로그램은 대량의 서열 데이터를 처리할 수 있도록 구성되었으며, 본 논문에서는 인간 염색체 22번에 대한 프로모터 예측 결과를 제시한다. Annotated된 936개의 유전자와 Promsearch가 예측한 프로모터간의 위치의 상관관계를 계산한 결과 87개에 대해 프로모터 예측 결과가 의미 있는 것으로 밝혀졌다. 예측의 민감도는 25%이며, Promsearch가 대규모 시퀀싱 프로젝트에서 나오는 대량의 서열 데이터를 1차적으로 분석하는 도구로서 사용될 수 있음을 확인하였다.