• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.762-766
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• 2003

In this paper, we present a new approach to solve the problem of estimating the camera 3-D location and orientation from a matched set of 3-D model and 2-D image features. An iterative least-square method is used to solve both rotation and translation simultaneously. Because conventional methods that solved for rotation first and then translation do not provide good solutions, we derive an error equation using roll-pitch-yaw angle to present the rotation matrix. To minimize the error equation, Levenberg-Marquardt algorithm is introduced with uniform sampling strategy of rotation space to avoid stuck in local minimum. Experimental results using real images are presented.

• 한국항행학회논문지
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• 제12권5호
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• pp.412-419
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• 2008

유전자 알고리즘은 효과적으로 최적의 해를 구하는 기법이나 진화연상산자의 선정에 따라 조기에 국부 최적해에 고착되어 전역 최적해로의 탐색을 어렵게 하는 문제점을 가지고 있다. 본 논문에서는 국부 최적해로 수렴하게 되는 원인을 분석하고, 국부 최적해에서 벗어나 전역 최적해로의 천이가 가능하도록 하는 방법을 제안하였다. 본 논문에서 사용한 방법은 평균 해밍거리에 따라 진화연산자를 가변시키는 방법으로서 국부 최적해에 고착되지 않도록 유전자에 다양성을 부여하여 지속적으로 모집단의 진화 특성을 유지하는 방법이다. 제안된 방법은 시뮬레이션을 통하여 효용성을 입증하였다.

• 한국생활과학회지
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• 제12권5호
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• pp.579-593
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• 2003

The purpose of this study was to investigate the social support, understanding of the children's problem in the female-headed single parents, and their child rearing methods. To obtain this purpose, in-depth interview was conducted to 8 female-headed single parents from March 3 to April 5, 2003. The contents of interviews were recorded and analyzed by qualitative method. The results were as follows: First, female-headed single parents were stuck for the social support and the relationships with parents-in-law were ruptured, especially. Secondly, female-headed single parents had well known about their children's daily life. Third, in the early stage of female-headed single parents, they had expressed the stresses in their hardship of life to their children, but it decreased whenever they were accustomed to their life.

• Transactions on Control, Automation and Systems Engineering
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• 제3권3호
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• pp.176-180
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• 2001

In this papers, we derive a simple kinematic and dynamic formulation of an unmanned electric bicycle. We also check the controllability of the stabilization problem of bicycle. We propose a new control algorithm for the self stabilization of unmanned bicycle with bounded wheel speed and steering angle by using nonlinear control based on the sliding patch and stuck phenomena which was introduced by W. Ham. We also propose a sort of optimal control strategy for steering angle and driving wheel speed that make the length of bicycle\`s path be the shortest. From the computer simulation results, we prove the validity of the proposed control algorithm.

• 전자공학회논문지C
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• 제34C권5호
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• pp.66-70
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• 1997

This paper presents a parallel combinatorial variant of evolution strategy (PCES) to solve well-known combinatorial optimization problems, Quadratic assignment problems (QAPs). The PCES reduces the possibility of getting stuck in local minima due to maintenance of subpopulation and thus it is more effective than the CES. Experiment results on two benchmark problems show that the PCES is better than the cES and the genetic algorithm(GA).

• 제어로봇시스템학회논문지
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• 제13권7호
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• pp.624-630
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• 2007

The dynamic window approach(DWA) is a well known technique for reactive collision avoidance. It shows safe and efficient performance in real-world experiments. However, a robot can get stuck in local minima because no information about the connectivity of the free space is used to determine the motion. The global DWA can solve this problem of local minima by adding a navigation function. Even with the global DWA, it is still difficult for a robot to execute an abrupt change in its direction, for example, entering from the corridor to a doorway. This paper proposes a modified global DWA using the included angles of waypoints extracted from an optimal path. This scheme enables the robot to decelerate in advance before turning into the doorway. Therefore the robot can reach the goal position more safely and efficiently at high speeds.

• ETRI Journal
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• 제38권5호
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• pp.896-902
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• 2016

Luby transform (LT) codes were the first practical rateless erasure codes proposed in the literature. The performances of these codes, which are iteratively decoded using belief propagation algorithms, depend on the degree distribution used to generate the coded symbols. The existence of degree-one coded symbols is essential for the starting and continuation of the decoding process. The absence of a degree-one coded symbol at any instant of an iterative decoding operation results in decoding failure. To alleviate this problem, we proposed a method used in the absence of a degree-one code symbol to overcome a stuck decoding operation and its continuation. The simulation results show that the proposed approach provides a better performance than a conventional LT code and memory-based robust soliton distributed LT code, as well as that of a Gaussian elimination assisted LT code, particularly for short data lengths.

• 산업경영시스템학회지
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• 제17권30호
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• pp.11-24
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• 1994

The problem of location for industries and residential quarters has undoubtedly been one of the most important factors to enhance human activities and standard of living. Nonetheless. there seem to be no such theories or approaches as to cope with this problem satisfactorily. As a matter of fact the evaluation of proposed locations so far has stuck to quantitative factors and thus the results are often rejected by the public or individuals. In deciding the location of industrial complex and/or residential quarters, the qualitative factors often play more important role than the quantitative factors. Moreover, it is quite possible for a proposed location to be disapproved for reasons other than quantifiable factors. This work presents an approach to multi-stage decision process of optimum location, particularly for residential quarters. The proposed approach consists of four stages. At the first stage, candidates for the location are searched and checked against musts. After this screening process, the candidates fulfilling the musts are evaluated both quantitatively and qualitatively at the second stage. The third stage is devoted to the integrated evaluation using diffrent weights for the two factors. At the final stage, a location is selected among the candidates evaluated at the earlier stages. This approach has been applied to and tested on a apartment-building project in Ulsan area. Difficulties arising from quantifying factors were encountered as expected. Sometimes decisions could be a matter of taste of the individuals concerned.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제16권11호
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• pp.1106-1110
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• 2010

본 논문은 자동화 컨테이너 터미널의 장치장에서 장치 위치 결정 전략을 다목적 진화 알고리즘(MOEA: Multi-Objective Evolutionary Algorithm)을 이용해 최적화하는 방안을 제안한다. 장치장의 해측과 육측 생산성은 서로 상충하기 때문에, 이 둘을 동시에 최대화하는 것은 불가능하다. 대신 본 논문에서는 MOEA를 이용해 파레토 최적해 집합(Pareto optimal set)을 구하였다. 초기 실험 결과 장치장의 컨테이너 점유율이 높은 어려운 문제의 경우, MOEA의 집단이 지역 해에 쉽게 빠지는 것을 확인하였다. 이에 본 논문에서는 난이도가 다른 두 개의 문제를 동시에 최적화함으로써 집단의 다양성을 유지하는 방안을 제안하였으며, 실험 결과 제안 방안이 단일 문제만 해결하는 방안에 비해 동일한 비용으로 더 좋은 전략을 얻을 수 있음을 확인하였다.

• 보존과학연구
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• 통권26호
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• pp.127-139
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• 2005

We have conserved the sword with round pommel with a tri-ring which was excavated from No. 1 tomb of the Duckcheon-ri at the Gyeongju and requested from Jungang Research Center of the Cultural Heritage. When this artifact excavated, it was pressed flat state because of the influence of earth pressure and stuck to a gravel and soil laid scattered on the wooden coffin. If the artifacts is handled without plan, it can be damaged, therefore that sword was collected together with soil using the Polyurethane foam. After the artifact which had a weak specific and was collected using a this method can be safetly collected as below; First, we made the supporter of article ordered using a silicon and gypsum. The silicon can conserve the weak point of the artifact because it has a flexible and smooth properties and the gypsum can adhere closely to the artifact because it has a little expansion and shrinking but a hard and fluid characters. Consequently, gypsum is a good complement to the weak point of the silicon. Second, During a remove gauze and a reinforcing agent from the surface of a artifact which was reinforced using a acetone steam method. The acetone steam method can be supplement to a dangerous problem of acetonedircet method because this can be damaged in a surface of the artifact.