• Journal of Information Processing Systems
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• 제9권2호
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• pp.315-332
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• 2013

This paper presents an approach for improving the use of VP-tree in video indexing and searching. A vantage-point tree or VP-tree is one of the metric space-based indexing methods used in multimedia database searches and data retrieval. Instead of relying on the Euclidean distance as a measure of search space, the proposed approach focuses on the trigonometric inequality for compressing the search range, which thus, improves the search performance. A test result of using 10,000 video files shows that this method reduced the search time by 5-12%, as compared to the existing method that uses the AESA algorithm.

• 융합보안논문지
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• 제19권2호
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• pp.73-81
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• 2019

본 논문은 시간 가중치 기반의 중간지점 탐색 알고리즘과 사용자 선호 기반 장소 추천 알고리즘을 이용한 사용자 중심의 중간지점 탐색 시스템을 제안한다. 제안된 시스템은 중간지점 탐색을 위하여 사용자간의 출발지점을 기준으로 각 사용자의 시간 가중치를 적용하여 중간 지점을 산출하는 중간지점 탐색 모듈과 각 사용자와 산출된 중간지점까지의 경로 탐색을 제공하기 위한 지점 탐색 제공 모듈로 구성된다. 또한, 중간지점 탐색 결과를 기반으로 사용자의 선호도 중심의 1장소 추천 기능을 포함하여 사용자의 이용률을 증대할 수 있도록 한다. 실험 결과, 제안된 시스템은 사용자 중심의 중간지점 및 장소 추천 기능을 통해 이용의 효율성을 증대시킬 수 있음을 확인하였다.

• 한국통신학회논문지
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• 제25권1B호
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• pp.128-140
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• 2000

본 논문에서는 이웃 탐색점에서의 평균 절대치 오차 (mean absoulte error, MAE) 및 탐색여역 줄임을 이용한 고속 블록 정합 알고리듬 제안하였다. 이 알고리듬은 두 단계로 구성되어있다. 첫 번째 단계에서는 탐색영역을 3$\times$3 크기의 영역으로 겹치지 않게 나눈 뒤, 각 영역의 중심 탐색점에 대하여 블록 정합을 행하여 MAE를 구하고, 이들 중 가장 작은 MAE를 기준 MAE로 정한다. 그리고, 두 번째 단계에서는 각 영역의 중심 탐색점에서의 MAE를 이용하여 각 3$\times$3 영역의 나머지 탐색점에서의 MAE의 최소 범위를 구한 뒤, 최소 범위가 기준 MAE로 결정된 탐색점 근처에 존재할 가능성이 매우 큼을 이용하여 기준 MAE로 결정된 탐색점을 중심으로 탐색영역의 크기를 줄인 뒤, 블록 정합이 필요한 탐색점에 대하여서만 블록 정합을 행함으로써 고속으로 움직임을 추정하였다. 모의 실험을 통하여 본 제안한 방법이 우수한 움직임 추정 성능을 유지하면서도 많은 계산량의 감소를 얻을 수 있음을 확인하였다.

• 대한전자공학회논문지SP
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• 제37권3호
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• pp.41-56
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• 2000

본 논문에서는 이웃 탐색점에서의 평균 절대치 오차(mean absolute error, MAE)를 이용하여 전역 탐색 알고리듬(full search algorithm, FSA)과 거의 같은 움직임 추정 성능을 얻으면서도 고속으로 움직임을 추정할 수 있는 2단계 고속 블록 정함 알고리듬을 제안하였다. 제안한 방법에서는 현재 탐색점에서 블록 정합을 통하여 얻을 수 있는 MAE의 최소 범위를 이웃 탐색점에서의 MAE를 이용하여 구한 뒤, 이를 이용하여 블록 정합이 필요한 탐색점에 대하여서만 블록 정합을 행하였다. 즉, 제안한 방법에서는 블록 정함이 필요한 탐색점 수를 줄임으로써 고속으로 움직임을 추정하였으며, 움직임 추정을 두 단계로 나누어 수행하였다 모의 설험을 통하여 제안한 방법이 FSA와 거의 같은 움직임 추정 성능을 유지하면서도 많은 계산량의 감소를 얻을 수 있음을 확인하였다

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 I
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• pp.274-277
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• 2003

Millimeter-wave networking is composed of narrow beam link. High directivity of the beam provides either advantage or disadvantage in comparison with conventional wide-lobe microwave communications. In such networks, it is very substantial that beam connecting point to point is fixed in right direction. It is major requirement in the beam network to keep the beam in best direction. In this paper, We propose the method to find a best suited direction of the antenna's beam using the Genetic Algorithm in point-to-point link. Proposed method presume that each station knows his direction $\theta$$_1$,$\theta$$_2$ at every step of Genetic Algorithm, then it can be expected that GA is possible to search the ideal solution. Intensity of the received signal is evaluated by the multiplication of lengths to the point which the lobe meets with the horizontal line.

• 여성건강간호학회지
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• 제8권4호
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• pp.608-618
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• 2002

The purpose of this study is to analyze the type of ego states and stress coping style on female college students who are in the course of nursing study. This study is performed in the view of Transactional Analysis and designed to scrutinize descriptive correlations between the type of ego states and stress coping style. The subject is consists of 144 freshmen and sophomore, 138 junior and senior students group, who are students of K nursing college located in Seoul. The sampling investigation period is on Sept. 14, 2002 to Oct. 26, 2002. The measuring instrument used for Transactional Analysis ego state is 50 items Ego-gram research paper devised by Dusay(1997). For studying coping style, Folkman & Lazarus's measurement(1984) was adopted, which is translated and modified by Han, and Oh,(1990). Statistic average and standard deviation were generated by using SPSS PC+, t-test and Pearson correlation. The results were as follows: 1) In the type of ego states on both groups(lower group : freshmen, sophomore upper group : junior, senior) indicated the arithmetic apex NP(maximum value), then the point A was high and the data made a down slope to point AC. In the comparison to type of ego states between two groups, only at point CP, the data value of upper year students represented higher than that of lower year ones by C(t=2.28, p=.023). In the psychological energy level of ego states, both groups indicated average level.2) Stress coping style of whole students were highly and affirmatively dedicated to research. Consecutive consequences follow like this(high to low) : the central point of problem, search for social support, hopeful aspect and indifference. Especially hopeful aspect(t=.67, p=.05), relaxation of tension(t=-2.16, p=.03) made significant difference each other in the view of arithmetic calculation 3) While verifying coping style in terms of ego states level between lower and upper students group, In type CP, high level ego states group indicated significant difference on stress coping style area than low leveled group and made such sequences as the central point of problem, hopeful aspect, search for social support, positive interest and relaxation of tension. In type NP, sequences such as the central point of problem, search for social support, positive interest and relaxation of tension were emerged with little differences. In type A, the central point of problem, positive interest and relaxation of tension. In type FC, hopeful aspect, search for social support, positive interest and relaxation of tension. In type AC, hopeful aspect and indifference were derived significantly different(p<.05). 4) In the aspect of relation between ego states and coping style, type CP presented the central point of problem and relaxation of tension, type NP presented positive interest, search for social support and the central point of problem, type A showed the central point of problem, positive interest and relaxation of tension, type FC showed relaxation of tension, positive interest, search for social support, indifference and the central point of problem, type AC showed hopeful aspect, indifference and the central point of problem. All the sequence shown above had high-to-low procedure and represented static relations each other(p<.05).

• Journal of Power Electronics
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• 제16권1호
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• pp.287-296
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• 2016

Conventional maximum power point tracking (MPPT) methods are ineffective under partially shaded conditions because multiple local maximum can be exhibited on power-voltage characteristic curve. This study proposes an improved cuckoo search (ICS) MPPT method after investigating the cuckoo search (CS) algorithm applied in solving multiple MPPT. The algorithm eliminates the random step in the original CS algorithm, and the conception of low-power, high-power, normal and marked zones are introduced. The adaptive step adjustment is also realized according to the different stages of the nest position. This algorithm adopts the large step in low-power and marked zones to reduce search time, and a small step in high-power zone is used to improve search accuracy. Finally, simulation and experiment results indicate that the promoted ICS algorithm can immediately and accurately track the global maximum under partially shaded conditions, and the array output efficiency can be improved.

• 한국컴퓨터그래픽스학회논문지
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• 제9권3호
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• pp.23-29
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• 2003

비디오 시퀀스의 현재 블록의 모션 벡터와 이전 블록의 모션 백터는 시간적 상관성을 갖고 있다. 따라서 이전 프레임 블록들로부터 많은 정보를 얻을 수 있다면 현재 블록의 오션 추정에 대한 성능을 높일 수 있고 또한 탐색 횟수를 줄임으로써 계산 복잡도를 크게 줄일 수 있다. 본 논문에서는 이전 프레임 블록과 주위 블록들의 모션 벡터로부터 예측된 모션 정보를 구하여, 이를 탐색 원점으로 사용하지 않고, 탐색 구간에 따라 적응적으로 해당 초기점으로 탐색 원점을 이동시켜 고속 탐색 패턴을 이용하여 블록 정합을 수행하는 블록 정합 모션 추정 방식을 제안한다. 실험 결과 제안된 방식은 기존의 예측 탐색 방식들에 비해 PSNR 값에 있어서 평균적으로 0.33~0.37[dB] 개선되고 영상에 따라 최고 1.05[dB] 정도 우수한 결과를 나타내었다. 또한 탐색 횟수에서는 기존의 탐색 알고리즘보다 29~97%를 줄일 수 있었고, 정확한 모션 벡터를 찾는 비교에 있어서도 월등히 우수한 결과를 나타내었다. 제안된 방식은 정량적인 결과뿐만 아니라 부호화후 복호화한 영상의 화질에 있어서도 다른 고속 탐색 알고리즘보다 월등히 우수한 화질을 제공한다.

• 대한조선학회논문집
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• 제42권2호
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• pp.175-182
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• 2005

It is necessary to develop an efficient optimization technique to optimize the engineering structures which have given design spaces, discrete design values and several design goals. As optimization techniques, direct search method and stochastic search method are widely used in designing of engineering structures. The merit of the direct search method is to search the optimum points rapidly by considering the search direction, step size and convergence limit. And the merit of the stochastic search method is to obtain the global optimum points by spreading point randomly entire the design spaces. In this paper, a Pareto optimal based multi-objective function method (PMOFM) is developed by considering the search direction based on Pareto optimal points, step size, convergence limit and random search generation . The PMOFM can also apply to the single objective function problems, and can consider the discrete design variables such as discrete plate thickness and discrete stiffener spaces. The design results are compared with existing Evolutionary Strategies (ES) method by performing the design of double bottom structures which have discrete plate thickness and discrete stiffener spaces.

• 대한전기학회논문지:시스템및제어부문D
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• 제53권1호
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• pp.22-31
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• 2004

This paper deals with the dynamic hand gesture recognition based on computer vision using neural networks. This paper proposes a global search method and a local search method to recognize the hand gesture. The global search recognizes a hand among the hand candidates through the entire image search, and the local search recognizes and tracks only the hand through the block search. Dynamic hand gesture recognition method is based on the skin-color and shape analysis with the invariant moment and direction information. Starting point and ending point of the dynamic hand gesture are obtained from hand shape. Experiments have been conducted for hand extraction, hand recognition and dynamic hand gesture recognition. Experimental results show the validity of the proposed method.