• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제15권8호
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• pp.606-610
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• 2009

위치기반 서비스(Location-Based Service)에서 개인정보 보호를 위해 사용자의 정확한 위치 정보를 숨기는 기법이 요구된다. 이를 위해 본 논분에서는 K-anonymity 및 L-diversity를 고려한 그리드 기반 cloaking 기법을 제안한다. 이 기법은 먼저 사용자가 요구하는 L개의 건물을 탐색하는 L-diversity를 수행한 후, K명의 사용자를 탐색하는 K-anonymity를 수행하여 최소한의 넓이는 가지는 cloaking 영역을 생성한다. 특히 cloaking 영역의 빠른 생성을 위해 효과적인 가지치기 방법을 사용한다. 마지막으로 성능평가를 통해, 본 논문에서 제안하는 cloaking 기법이 cloaking 영역 크기에 따른 질의 처리 시간 측면에서 기존의 연구보다 우수함을 보인다.

• 한국멀티미디어학회논문지
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• 제13권6호
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• pp.833-840
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• 2010

In this paper a method for detecting and extracting the face from the image in YCbCr spaceis proposed. The face region is obtained from the complex original image by using the difference method and the face color information is taken from the reduced face region throughthe Ellipse clustering method. The experimental results showed that the proposed method can efficiently detect and extract the face from the original image under the general light intensity except for low luminance.

• 전력전자학회논문지
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• 제19권5호
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• pp.463-469
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• 2014

This paper proposes a maximum torque operation strategy for the direct torque control of a surface-mounted permanent-magnet synchronous motor (SPMSM). The proposed method analyzes the available operation region of the stator flux of the SPMSM under voltage and current constraints. Based on this analysis, the optimal stator flux trajectory that yields the maximum torque is obtained across the entire operation region, including constant torque and constant power regions. The proposed strategy is also applicable in the flux-weakening region II operation of the SPMSM, which has no speed limit. The validity of the proposed method is verified through experiments conducted on an 800 W SPMSM drive system.

• Journal of Information Processing Systems
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• 제14권5호
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• pp.1293-1300
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• 2018

For the disadvantages of multi-scale geometric analysis methods such as loss of definition and complex selection of rules in image fusion, an improved multi-focus image fusion method is proposed. First, the initial fused image is quickly obtained based on the lifting stationary wavelet transform, and a simple normalized cut is performed on the initial fused image to obtain different segmented regions. Then, the original image is subjected to NSCT transformation and the absolute value of the high frequency component coefficient in each segmented region is calculated. At last, the region with the largest absolute value is selected as the postfusion region, and the fused multi-focus image is obtained by traversing each segment region. Numerical experiments show that the proposed algorithm can not only simplify the selection of fusion rules, but also overcome loss of definition and has validity.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2011년도 추계학술대회
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• pp.911-914
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• 2011

손 영역을 찾는 것은 사용자 중심의 인터페이스를 제공하는 데 있어서 꼭 필요한 기술이며 이를 위해 많은 연구가 진행되어 왔다. 본 논문은 HSV 공간을 기반으로 한 역 투영 기법을 사용하여 손영역 검출을 수행하였으며, 휴 모멘트를 통해 추출된 손 영역을 분석, 손 모양 인식에 대한 방법을 제안한다. 역 투영 기법을 통해 손 영역 검출에 대한 신뢰도를 높였으며, 휴 모멘트를 통해 손모양을 구분할 수 있음을 확인하였다.

• 대한전기학회논문지:시스템및제어부문D
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• 제53권2호
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• pp.118-126
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• 2004

The modified Wiener filtering method is proposed for effective noise suppression in edge region of images corrupted by additive white gaussian noise. Although the pixels classified as a edge region in the conventional Wiener filter have lots of noise components, the conventional Wiener filter cannot remove noise effectively due to the preserving of edges. To reduce noise well in edge region, we modify filter coefficients of the conventional Wiener filter. The modified filter coefficients increase in noise suppression effect in edge region, while they preserve edges for strong edge region. From simulation (256${\times}$256 size, 256 graylevel images) filtered images by the proposed method show much improved subjective image quality with higher peak signal-to-noise ratio compared to those by the conventional Wiener filtering.

• IEIE Transactions on Smart Processing and Computing
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• 제1권2호
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• pp.73-77
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• 2012

This paper reports a combined depth- and model-based face detection and tracking approach. The proposed algorithm consists of four functional modules; i) color-based candidate region extraction, ii) generation of the depth histogram for handling occlusion, iii) rotation-invariant face region detection using ellipse fitting, and iv) face tracking based on motion prediction. This technique solved the occlusion problem under complicated environment by detecting the face candidate region based on the depth-based histogram and skin colors. The angle of rotation was estimated by the ellipse fitting method in the detected candidate regions. The face region was finally determined by inversely rotating the candidate regions by the estimated angle using Haar-like features that were robustly trained robustly by the frontal face.

• 대한전기학회논문지:시스템및제어부문D
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• 제52권3호
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• pp.148-155
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• 2003

In this paper, a nonlinear anisotropic filtering method without the loss of important information happened due to the repeated filtering in magnetic resonance images is proposed. First of all original images are divided into four regions, e.g., SPR(Strong Plain Region), EPR(Easy Plain Region), SER(Strong Edge Region), and EER(Easy Edge Region). An optimal template among multiple templates is selected, then the nonlinear anisotropic filtering based on the template is applied in pixel by pixel basis. In the proposed algorithm, filtering strength of EER containing important information is adjusted very weak and filtering strength for remaining regions is also adjusted according to the degree of the importance. In spite of repeated filtering, resulting images by the proposed method could still preserve anatomy information of original images without any degradation. Compared to the existing nonlinear anisotropic filtering, the proposed filtering method with multiple templates provides higher reliability for filtered images.

• Journal of Information Processing Systems
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• 제14권4호
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• pp.892-903
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• 2018

The paper proposes a novel gait recognition algorithm based on feature fusion of gait energy image (GEI) dynamic region and Gabor, which consists of four steps. First, the gait contour images are extracted through the object detection, binarization and morphological process. Secondly, features of GEI at different angles and Gabor features with multiple orientations are extracted from the dynamic part of GEI, respectively. Then averaging method is adopted to fuse features of GEI dynamic region with features of Gabor wavelets on feature layer and the feature space dimension is reduced by an improved Kernel Principal Component Analysis (KPCA). Finally, the vectors of feature fusion are input into the support vector machine (SVM) based on multi classification to realize the classification and recognition of gait. The primary contributions of the paper are: a novel gait recognition algorithm based on based on feature fusion of GEI and Gabor is proposed; an improved KPCA method is used to reduce the feature matrix dimension; a SVM is employed to identify the gait sequences. The experimental results suggest that the proposed algorithm yields over 90% of correct classification rate, which testify that the method can identify better different human gait and get better recognized effect than other existing algorithms.

• 한국산학기술학회논문지
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• 제6권5호
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• pp.367-372
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• 2005

본 논문은 가변 영역을 이용한 내용기반 영상 검색 방법을 제안한다. 내용기반 검색에서 색상을 이용하는 경우 대부분 컬러 히스토그램을 사용한다. 그러나 기존 컬러 히스토그램 검색 방법들은 양자화 오류 등의 이유로 정확성이 떨어지고, 공간정보가 부족한 단점이 있다. 이를 극복하기 위해 제안 방법은 색상 정보를 HSV 공간으로 변환하여 순수 색상 정보인 hue 성분만을 양자화하여 히스토그램을 구한다. 한편 공간정보가 부족한 문제점을 해결하기 위해 색상 특징과 영역간의 상관관계를 고려하여 객체 영역을 선정한다. 선정된 객체 영역에서는 영역 크기를 유지한다. 그러나 비객체 영역은 한 개의 영역으로 통합된다. 가변적인 영역이 선정된 후 색상 특징을 이용해 검색한다. 실험 결과 제안방법이 정확율(precision) 평균으로 10$\%$ 향상되었다.