• 한국정보통신학회논문지
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• 제9권3호
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• pp.669-675
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• 2005

본 논문에서는 카타디옵트릭 카메라로부터 획득한 전 방향 구면 왜곡 영상에서의 좌표를 실제 거리좌표로 변환하기 위해서 3차원 포물면 좌표 변환 방법과 Delta-bar-delta 알고리즘에 의한 좌표 교정방법을 제시하였다. 실험을 통해 살펴본 결과 제안된 좌표 변환 방법이 환경 변수에 민감한 좌표 변환에서의 정확성 및 신뢰성을 가짐을 알 수 있었다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2001년도 추계종합학술대회
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• pp.579-582
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• 2001

벡터변형은 벡터 양자화(VQ)와 부호화를 통합한 새로운 방법이다. 최근까지 부호화에 적용된 코드북 생성은 LBG 알고리즘이었으나 신경회로망을 기반으로 한 자기생성 특성맵(SOFM: Self Organizing Feature Map)의 장점을 이용하면 시스템의 성능을 개선할 수 있다는 점에 착안하였다. 본 논문에서는 SOFM 알고리즘을 적용한 VTC(Vector Transformation coding)코드북 생성과 LBG 알고리즘의 부호화률에 대한 결과를 비교하여 분석하였다. 벡터 양자화의 문제점은 계산의 복잡성과 코드북 생성에 있으므로 본 연구에서는 이 문제의 해결을 위해 신경망 접근법을 제안한다.

• 음성과학
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• 제11권4호
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• pp.75-88
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• 2004

In this paper, we propose a new approach to sequential linear regression adaptation of continuous density hidden Markov models (CDHMMs) based on transformation space model (TSM). The proposed TSM which characterizes the a priori knowledge of the training speakers associated with maximum likelihood linear regression (MLLR) matrix parameters is effectively described in terms of the latent variable models. The TSM provides various sources of information such as the correlation information, the prior distribution, and the prior knowledge of the regression parameters that are very useful for rapid adaptation. The quasi-Bayes (QB) estimation algorithm is formulated to incrementally update the hyperparameters of the TSM and regression matrices simultaneously. Experimental results showed that the proposed TSM approach is better than that of the conventional quasi-Bayes linear regression (QBLR) algorithm for a small amount of adaptation data.

• 대한임베디드공학회논문지
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• 제14권4호
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• pp.197-205
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• 2019

In this paper, an efficient single dehazing algorithm is proposed based on linear transformation by assuming that a linear relationship exists in saturation component between the haze image and haze-free image. First, we analyze the linearity of saturation channel, estimate the medium transmission map in terms of the saturation component. Then, the intensity of haze-free image is assumed by using CLAHE to enhance contrast of haze image. Experimental results demonstrate that proposed algorithm can naturally recover the image, especially can remove color distortion caused by conventional methods. Therefore, our approach is competitive with other state-of-the art single dehazing methods.

• 대한전자공학회논문지SP
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• 제40권6호
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• pp.71-83
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• 2003

본 논문에서는 G.729A와 SMV 음성부호화기를 위한 새로운 파라미터 직접 변환 방식의 상호부호화 알고리듬을 제안한다. 상호부호화를 위하여 부가적인 복호화, 부호화 과정을 거쳐야하는 기존의 Tandem 방식과 달리 제안된 파라미터 직접 변환 방식에서는 양 음성부호화기가 음성을 부호화하기 위하여 공통적으로 사용하는 파라미터들이 직접 변환된다. SMV 에서 G.729A로의 트랜스코딩에서는 LSP 변환, 피치 지연 변환, 낮은 전송률에서의 트랜스코딩 등의 알고리듬을 제안하고, G.729A에서 SMV로의 트랜스코더에서는 LSP 변환, 피치 지연 변환, 전송률 결정 등의 알고리듬을 제안한다 제안된 알고리듬을 다양한 방법으로 평가해본 결과 기존의 Tandem 방식과 비교하여 계산량과 지연 시간을 줄이면서도 동등한 음질 또는 향상된 음질을 구현함을 확인할 수 있었다.

• Journal of Electrical Engineering and Technology
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• 제12권5호
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• pp.1697-1708
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• 2017

This paper proposes an algorithm for the differential protection of an Indirect Symmetrical Phase Shift Transformer (ISPST) by considering the different behaviors of the compensated differential current under internal fault and magnetizing inrush conditions. In this algorithm, a criterion function is defined which is based on the difference of amplitude of the wavelet transformation over a specific frequency band. The function has been used for the discrimination between three phase magnetizing inrush and internal fault condition and requires less than a quarter cycle after disturbance. This method is independent of any coefficient or threshold values of wavelet transformation. The merit of this algorithm is demonstrated by the simulation of different faults in series and excitation unit and magnetizing inrush with varying switching conditions on ISPST using PSCAD/EMTDC. Due to unavailability of in-field large interconnected transformers for such a large number of destructive tests, the results are further verified by Real Time Digital Simulator (RSCAD/RTDS). The proposed algorithm has been compared with the conventional harmonic restraint based method that justifies the application of wavelet transform for differential protection of ISPST. The proposed algorithm has also been verified for different rating of ISPSTs and satisfactory results were obtained.

• 한국정밀공학회지
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• 제21권12호
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• pp.84-91
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• 2004

A CCD camera with a laser stripe was applied to realize the automatic weld seam tracking in GMAW. It takes relatively long time to process image on-line control using the basic Hough transformation, but it has a tendency of robustness over the noises such as spatter and arc tight. For this reason, it was complemented with adaptive Hough transformation to have an on-line processing ability for scanning specific weld points. The adaptive Hough transformation was used to extract laser stripes and to obtain specific weld points. The 3-dimensional information obtained from the vision system made it possible to generate the weld torch path and to obtain the information such as width and depth of weld line. In this study, a neural network based on the generalized delta rule algorithm was adapted for the process control of GMA, such as welding speed, arc voltage and wire feeding speed.

• 제어로봇시스템학회논문지
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• 제15권5호
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• pp.465-472
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• 2009

This paper proposes a multimodal information transformation system that converts the image information to the voice information to provide the sight impaired people with walking area and obstacles, which are extracted by an acquired image from a single CCD camera. Using a chain-code line detection algorithm, the walking area is found from the vanishing point and boundary of a sidewalk on the edge image. And obstacles are detected by Gabor filter of extracting vertical lines on the walking area. The proposed system expresses the voice information of pre-defined sentences, consisting of template words which mean walking area and obstacles. The multi-modal information transformation system serves the useful voice information to the sight impaired that intend to reach their destination. The experiments of the proposed algorithm has been implemented on the indoor and outdoor environments, and verified its superiority to exactly provide walking parameters sentences.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권12호
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• pp.5785-5804
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• 2019

The information of localization is a fundamental requirement in wireless sensor network (WSN). The method of distance vector-hop (DV-Hop), a range-free localization algorithm, can locate the ordinary nodes by utilizing the connectivity and multi-hop transmission. However, the error of the estimated distance between the beacon nodes and ordinary nodes is too large. In order to enhance the positioning precision of DV-Hop, fast triangle flip bat algorithm, which is based on curve strategy and rank transformation (FTBA-TCR) is proposed. The rank is introduced to directly select individuals in the population of each generation, which arranges all individuals according to their merits and a threshold is set to get the better solution. To test the algorithm performance, the CEC2013 test suite is used to check out the algorithm's performance. Meanwhile, there are four other algorithms are compared with the proposed algorithm. The results show that our algorithm is greater than other algorithms. And this algorithm is used to enhance the performance of DV-Hop algorithm. The results show that the proposed algorithm receives the lower average localization error and the best performance by comparing with the other algorithms.

• 한국정보통신학회논문지
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• 제15권8호
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• pp.1665-1674
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• 2011

본 논문에서는 유색잡음에 의해 오염된 음성신호의 음성향상 알고리즘을 제안한다. 유색잡음과 음성신호가 서로 상관이 없을 경우 유색잡음은 백색화 변환을 통해 무색잡음으로 변환된다. 이 변환된 신호를 음성신호 향상을 위한 일반화된 부공간 접근법에 적용한다. 전처리 과정에서의 백색화 변환으로 발생되는 음성 스펙트럼 왜곡은 제안한 알고리즘의 후처리를 통해 역 백색화하여 복구한다. 제안한 알고리즘의 성능을 컴퓨터 시뮬레이션으로 확인하였다. 사용한 유색잡음은 자동차 잡음과 멀티 토커 배블 잡음이다. AURORA 및 TIMIT 데이터 베이스에서 취득한 데이터로 실험했을 때 제안하는 방법이 신호대잡음비 및 스펙트럼 왜곡 측면에서 기존 접근법보다 개선됨을 확인하였다.