• Journal of KIISE:Software and Applications
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• v.34 no.9
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• pp.857-868
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• 2007

The good classifier ensemble should have a high complementarity among classifiers in order to produce a high recognition rate and its size is small in order to be efficient. This paper proposes a classifier ensemble selection algorithm with coarse-to-fine stages. for the algorithm to be successful, the original classifier pool should be sufficiently diverse. This paper produces a large classifier pool by combining several different classification algorithms and lots of feature subsets. The aim of the coarse selection is to reduce the size of classifier pool with little sacrifice of recognition performance. The fine selection finds near-optimal ensemble using genetic algorithms. A hybrid genetic algorithm with improved searching capability is also proposed. The experimentation uses the worldwide handwritten numeral databases. The results showed that the proposed algorithm is superior to the conventional ones.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1997.11a
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• pp.87-92
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• 1997

본 논문은 저비용이면서 정확한 제어를 수행하는 새로운 퍼지 제어기의 VHDL 설계 및 시뮬레이션을 다룬다. 제안한 퍼지 제어기 (Fuzzy Logic Controller : FLC)의 정확한 비퍼지화 연산시 소속값뿐 아니라 소속 함수의 폭을 고려함으로서 ？어진다. 제안한 퍼지 제어기 저비용성은 기존의 FLC를 다음과 같이 개조함으로서 이루어진다. 먼저, MAX-MIN 추론이 레지스터 파일의 형태로 쉽게 구현 가능한 read-modify-write 연산에 의해 대치된다. 두 번째, COG 비퍼지화기에서 요구하는 제산 연산을 모멘트 균형점의 탐색에 의해 피할 수 있다. 제안한 COG 퍼지화기는 곱셈기가 부가적으로 요구되며 모멘트 균형점의 탐색 시간이 오래 걸리는 단점이 있다. 부가적 곱셈기 요구에 의한 하드웨어 복잡도 증가 문제는 곱셈기를 확률론적 AND 연산에 의해 해결할 수 있고, 오랜 탐색 시간 문제는 coarse-to fine 탐색 알고리즘에 의해 크게 경감될 수 있다. 제안한 퍼지 제어기의 각 모듈은 VHDL에 의해 구조적 수준 및 행위적 수준에서 기술되고, 이들이 제대로 동작하는지 여부를 SYNOPSYS사의 VHDL 시뮬레이션 상에서 트럭 후진 주차 문제에 적용하여 검증하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.236-241
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• 2004

In this paper, the dual stage interaction between the coarse actuator and the fine actuator of an optical disk drive and the control method to enhance the track pull-in performance are discussed. First, the interaction analyses for the dual stage, and the experiments to find the each actuator dynamics are studied. From the experiments results, some physical parameters was derived, then, some simulations are performed to find the residual vibration effect of the fine actuator during seek motion. Second, the fine actuator control method to reduce the relative velocity, which is a key factor in track pull-in performance, between the target track and beam spot is proposed. From simulations, we show that fine actuator control which has same frequency and same phase of the disturbance is effective to reduce the relative velocity, hence, the control method is good approach in the track pull-in enhancement. Finally, the some comments are discussed briefly.

• Korean Journal of Remote Sensing
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• v.35 no.6_1
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• pp.945-957
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• 2019

In this study, we propose a coarse to fine image registration method for eliminating geometric error between images over agricultural areas acquired using Unmanned Aerial Vehicle (UAV). First, images of agricultural area were acquired using UAV, and then orthophotos were generated. In order to reduce the probability of extracting outliers that cause errors during image registration, the region of interest is selected by using the metadata of the generated orthophotos to minimize the search area. The coarse image registration was performed based on the extracted tie-points using the Speeded-Up Robust Features (SURF) method to eliminate geometric error between orthophotos. Subsequently, the fine image registration was performed using tie-points extracted through the Mutual Information (MI) method, which can extract the tie-points effectively even if there is no outstanding spatial properties or structure in the image. To verify the effectiveness and superiority of the proposed method, a comparison analysis using 8 orthophotos was performed with the results of image registration using the SURF method and the MI method individually. As a result, we confirmed that the proposed method can effectively eliminated the geometric errors between the orthophotos.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.11
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• pp.66-72
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• 2014

Histogram of oriented gradient (HOG) feature is widely used in vision-based pedestrian detection. The interpolation is the most important technique in HOG feature calculation to provide high detection rate. In interpolation technique of HOG feature calculation, two nearest orientation bins to gradient orientation for each pixel and the corresponding weights are required. In this paper, therefore, an efficient gradient orientation bin and weight calculation circuit for HOG feature is proposed. In the proposed circuit, pre-calculated values are defined in tables to avoid the operations of tangent function and division, and the size of tables is minimized by utilizing the characteristics of tangent function and weights for each gradient orientation. Pipeline architecture is adopted to the proposed circuit to accelerate the processing speed, and orientation bins and the corresponding weights for each pixel are calculated in two clock cycles by applying efficient coarse and fine search schemes. Since the proposed circuit calculates gradient orientation for each pixel with the interval of $1^{\circ}$ and determines both orientation bins and weights required in interpolation technique, it can be utilized in HOG feature calculation to support interpolation technique to provide high detection rate.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.11 s.104
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• pp.1276-1286
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• 2005

In this paper, the dual stage interaction between the coarse actuator and the fine actuator of an optical disk drive is studied, and the new control method to enhance the track pull-in performance using fine actuator control is proposed. First, the dynamic analysis for the dual stage and the experiments to find the each actuator dynamics are performed. From the experiments, some physical parameters of the actuators were derived, then, some simulations are performed to find the interaction effect of the fine actuator during seek motion. Second, the center servo which suppresses the vibration of fine actuator during seek motion is designed and evaluated. And the fine actuator control to reduce the relative velocity between the target track and beam spot is proposed. From simulations, we show that fine actuator control which has same frequency and same phase of the disturbance is effective to reduce the relative velocity, and this result leads to track pull-in enhancement. Hence, the proposed control method is good approach to improve the track pull-in performance. Finally, the realization of the proposed method and some comments of it are briefly discussed.

• Journal of the Korean Institute of Intelligent Systems
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• v.8 no.2
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• pp.70-81
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• 1998

This paper proposes an accurate and cost-effective COA defuzzifier of fuzzy logic controller (FLC). The accuracy of the proposed COA defuzzifier is obtained by involving both membership values and spans of membership functions in calculating a crisp value. The cost-effectiveness of the proposed COA defuzzifier is obtained by replacing the division in the COA defuzzifier by finding an equilibrium point of both the left and right moments. The proposed COA defuzzifier has two disadvantages that it ncreases the hardware complexity due to the additional multipliers and it takes a lot of computation time to find the moment equilibrium point. The first disadvantage is overcome by replacing the multipliers with the stochastic AND operations. The second disadvantage is alleviated by using a coarse-to-fine searching algorithm that accelerates the finding of moment equilibrium point. Application of the proposed COA defuzzifier to the truck backer-upper control problem is performed in the VHDL simulation and the control accuracy of the proposed COA defuzzifier is compared with that of the conventional COA defuzzifier in terms of average tracing distance.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.37 no.6
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• pp.491-498
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• 2019

This study analyzed how the accuracy of co-registration varies depending on the convergence angles between two KOMPSAT-3·3A images. Most very-high-resolution satellite images provide initial coordinate information through metadata. Since the search area for performing image co-registration can be reduced by using the initial coordinate information, in this study, the mutual information method showing high matching reliability in the small search area is used. Initial coarse co-registration was performed by using multi-spectral images with relatively low resolution, and precise fine co-registration was conducted centering on the region of interest of the panchromatic image for more accurate co-registration performance. The experiment was conducted by 120 combination of 16 KOMPSAT-3·3A 1G images taken in Daejeon area. Experimental results show that a correlation coefficient between the convergence angles and fine co-registration errors was 0.59. In particular, we have shown the larger the convergence angle, the lower the accuracy of co-registration performance.

• The KIPS Transactions:PartB
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• v.12B no.4 s.100
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• pp.429-436
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• 2005

A simple stereo matching algorithm using population-based incremental learning(PBIL) is proposed in this paper to decrease the general problem of genetic algorithms, such as memory consumption and inefficiency of search. PBIL is a variation of genetic algorithms using stochastic search and competitive teaming based on a probability vector. The structure of PBIL is simpler than that of other genetic algorithm families, such as serial and parallel ones, due to the use of a probability vector. The PBIL strategy is simplified and adapted for stereo matching circumstances. Thus, gene pool, chromosome crossover, and gene mutation we removed, while the evolution rule, that fitter chromosomes should have higher survival probabilities, is preserved. As a result, memory space is decreased, matching rules are simplified and computation cost is reduced. In addition, a scheme controlling the distance of neighbors for disparity smoothness is inserted to obtain a wide-area consistency of disparities, like a result of coarse-to-fine matchers. Because of this scheme, the proposed algorithm can produce a stable disparity map with a small fixed-size window. Finally, an alterative version of the proposed algorithm without using probability vector is also presented for simpler set-ups.

• The Journal of the Petrological Society of Korea
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• v.25 no.3
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• pp.299-310
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• 2016

The Stele for Buddhist Monk Wonjong at Godalsa Temple Site was destroyed a long time ago. Only the tortoise-shaped pedestal and the ornamental capstone in the form of a hornless dragon remain at the site and the broken stele body is stored at the National Museum of Korea today. The stele is made of two kinds of rocks that are coarse-grained biotite granite for the pedestal and the capstone, and fine-grained biotite granite including hornblende assemblages and feldspar phenocrysts for the stele body. The coarse-grained biotite granite of the pedestal and capstone showed same magnetic susceptibility and lithological characteristics with biotite granite outcrops in Yeoju area, whereas the fine-grained granite of the stele body did not. To find a provenance of the stele body stone, we investigated Korean granites in terms of magnetic susceptibility, lithology and old recordings about construction process of the stele. As a result, Haeju granite is the most likely to be a cognate rock of the stele body stone as it has same texture and lithological characteristics like color, hornblende assemblages, mineral composition and magnetic susceptibility. It is imported from Haeju (North Korea) to South Korea via China commercially, and the most suitable for a replica stone of the stele body.