• 전자공학회논문지B
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• 제33B권8호
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• pp.81-95
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• 1996

In this paper, we propose a motio estiamtion algorithm using low-resolution quantization to reduce the computation of the full search algorithm. The proposed algorithm consists of the low-resolution search which determins the candidate motion vectors by comparing the low-resolution image and the full-resolution search which determines the motion vector by comparing the full-resolution image on the positions of the candidate motion vectors. The low-resolution image is generated by subtracting each pixel value in the reference block or the search window by the mean of the reference block, and by quantizing it is 2-bit resolution. The candidate motion vectors are determined by counting the number of pixels in the reference block whose quantized codes are unmatched to those in the search window. Simulation results show that the required computational cost of the proposed algorithm is reduced to 1/12 of the full search algorithm while its performance degradation is 0.03~0.12 dB.

• 제어로봇시스템학회논문지
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• 제3권2호
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• pp.156-161
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• 1997

In this thesis, based on Genetic Algorithm, a new route search algorithm is presented to search an optimal route between the origin and the destination in intelligent route guidance systems in order to minimize the route traveling time. The proposed algorithm is effectively employed to complex road networks which have diverse turn constrains, time-delay constraints due to cross signals, and stochastic traffic volume. The algorithm is also shown to significantly promote search efficiency by changing the population size of path individuals that exist in each generation through the concept of age and lifetime to each path individual. A virtual road-traffic network with various turn constraints and traffic volume is simulated, where the suggested algorithm promptly produces not only an optimal route to minimize the route cost but also the estimated travel time for any pair of the origin and the destination, while effectively avoiding turn constraints and traffic jam.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제15권4호
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• pp.267-275
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• 2011

This paper proposes a new quickly convergent pattern search quasi-Newton algorithm that employs the multi-step version of the Symmetric Rank One (SRI). The new algorithm works on the factorizations of the inverse Hessian approximations to make available a sequence of convergent positive bases required by the pattern search process. The algorithm, in principle, resembles that developed in [1] with multi-step methods dominating the dervation and with numerical improvements incurred, as shown by the numerical results presented herein.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제10권1호
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• pp.57-65
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• 2004

서로 다른 형태와 크기를 가지는 탐색패턴과 움직임 벡터의 분포는 블록 정합 알고리즘에서 탐색 속도와 화질을 좌우하는 중요한 요소이다. 본 논문에서는 단위 다이아몬드패턴과 납작한 육각패턴을 이용한 새로운 고속 블록 정합 알고리즘을 제안한다. 이 알고리즘은 단위 다이아몬드패턴을 이용하여 적은 탐색점으로 움직임이 적은 벡터를 우선 찾은 다음에 움직임이 큰 벡터에 대해서는 납작한 육각패턴을 이용하여 고속으로 움직임 벡터를 찾게 하였다. 실험결과, 제안된 알고리즘은 육각패턴 탐색 알고리즘에 비하여 움직임 벡터 예측의 속도에 있어서 약 11∼51%의 높은 성능 향상을 보였으며 화질 또한 PSNR 기준으로 약 0.05∼0.74㏈의 향상을 보였다.

• Nuclear Engineering and Technology
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• 제53권11호
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• pp.3665-3674
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• 2021

One of the important parts of the in-core fuel management is loading pattern optimization (LPO). The loading pattern optimization as a reasonable design of the in-core fuel management can improve both economic and safe aspects of the nuclear reactor. This work proposes the hybrid of fuzzy logic controller with harmony search algorithm (HS) for loading pattern optimization in a pressurized water reactor. The music improvisation process to find a pleasing harmony is inspiring the harmony search algorithm. In this work, the adjustment of the harmony search algorithm parameters such as the bandwidth and the pitch adjustment rate are increasing performance of the proposed algorithm which is done through a fuzzy logic controller. Hence, membership functions and fuzzy rules are designed to improve the performance of the HS algorithm and achieve optimal results. The objective of the method is finding an optimum core arrangement according to safety and economic aspects such as reduction of power peaking factor (PPF) and increase of effective multiplication factor (Keff). The proposed approach effectiveness has been tried in two cases, Michalewicz's bivariate function problem and NEACRP LWR core. The results show that by using fuzzy harmony search algorithm the value of the fitness function is improved by 15.35%. Finally, with regard to the new solutions proposed in this research it could be used as a trustworthy method for other optimization issues of engineering field.

• Nuclear Engineering and Technology
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• 제55권8호
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• pp.3030-3038
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• 2023

Nowadays, mobile robots have been used to search for uncontrolled radioactive source in indoor environments to avoid radiation exposure for technicians. However, in the indoor environments, especially in the presence of obstacles, how to make the robots with limited sensing capabilities automatically search for the radioactive source remains a major challenge. Also, the source search efficiency of robots needs to be further improved to meet practical scenarios such as limited exploration time. This paper proposes an automatic source search strategy, abbreviated as ACA: the location of source is estimated by a convolutional neural network (CNN), and the path is planned by the A-star algorithm. First, the search area is represented as an occupancy grid map. Then, the radiation dose distribution of the radioactive source in the occupancy grid map is obtained by Monte Carlo (MC) method simulation, and multiple sets of radiation data are collected through the eight neighborhood self-avoiding random walk (ENSAW) algorithm as the radiation data set. Further, the radiation data set is fed into the designed CNN architecture to train the network model in advance. When the searcher enters the search area where the radioactive source exists, the location of source is estimated by the network model and the search path is planned by the A-star algorithm, and this process is iterated continuously until the searcher reaches the location of radioactive source. The experimental results show that the average number of radiometric measurements and the average number of moving steps of the ACA algorithm are only 2.1% and 33.2% of those of the gradient search (GS) algorithm in the indoor environment without obstacles. In the indoor environment shielded by concrete walls, the GS algorithm fails to search for the source, while the ACA algorithm successfully searches for the source with fewer moving steps and sparse radiometric data.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.285-288
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• 2005

In this paper, we propose a two step Binary Exponential search algorithm for rapid acquisition time of UWB(Ultra Wide Band) signal on UWB communication systems. Previous proposed timing acquisition algorithm is searching whole frame that consist of the number of n Bins to terminate search, however this paper proposed two step Binary Exponential search algorithm can achieve remarkable reduction of UWB signal acquisition time as limiting search group. Proposed search algorithm is consisting of search group establishment step and Bit Reversing of search group establishment step.

• 제어로봇시스템학회논문지
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• 제17권2호
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• pp.145-148
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• 2011

In this paper, we proposed a search method for structured light pixels of omnidirectional structured light image. Since the omnidirectional structured light image is composed of several circular arc segments, the proposed algorithm searches the structured light pixels in radial direction rather than horizontal or vertical directions. The proposed search algorithm is based on the well-known Bresenham raster algorithm for line drawing in discrete integer space, thereby computation of the algorithm is very efficient. Comparison results between the proposed search algorithm and the conventional horizontal search are presented in experiments.

• Journal of Information Processing Systems
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• 제16권3호
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• pp.639-647
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• 2020

In the vibration target localization algorithms based on time difference of arrival (TDOA), Fang algorithm is often used in practice because of its simple calculation. However, when the delay estimation error is large, the localization equation of Fang algorithm has no solution. In order to solve this problem, one dimensional search location algorithm based on TDOA is proposed in this paper. The concept of search is introduced in the algorithm. The distance d1 between any single sensor and the vibration target is considered as a search variable. The vibration target location is searched by changing the value of d1 in the two-dimensional plane. The experiment results show that the proposed algorithm is superior to traditional methods in localization accuracy.

• 한국컴퓨터산업학회논문지
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• 제4권12호
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• pp.1075-1082
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• 2003

본 논문에서는 움직임 추정을 위한 Efficient Center- Biased Hybrid Search (ECBHS) 알고리즘을 제안하였다. 제안된 알고리즘은 Center-Biased Hybrid Search (CBHS) 알고리즘에 기초하고 있다. 제안된 알고리즘은 +, X, 다이아몬드 탐색형태를 결합하여 탐색 윈도우의 중앙으로부터 3pel 이내에 분포하는 움직임 벡터를 찾는 과정에서 탐색점을 효과적으로 감소시킨다. ECBHS는 UCHDS 및 CBHS와 거치 동일한 움직임 추정 정확도를 유지하면서 움직임 추정을 위한 연산량을 효과적으로 감소시킨다. 제안된 알고리즘의 효율성을 실험을 통하여 확인하였다.