• 음성과학
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• 제4권2호
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• pp.5-15
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• 1998

This paper proposes a speech state-dependent spectral subtraction method to regulate the blind spectral subtraction for improved enhancement. In the proposed method, a modified subtraction rule is applied over the speech selectively contingent to the speech state being voiced or unvoiced, in an effort to incorporate the acoustic characteristics of phonemes. In particular, the objective of the proposed method is to remedy the subtraction induced signal distortion attained by two state-dependent procedures, spectrum sharpening and minimum spectral bound. In order to remove the residual noise, the proposed method employs a procedure utilizing the masking effect. Proposed spectral subtraction including state-dependent subtraction and residual noise reduction using the masking threshold shows effectiveness in compensation of spectral distortion in the unvoiced region and residual noise reduction.

• 대한방사선기술학회지:방사선기술과학
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• 제7권1호
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• pp.13-21
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• 1984

Subtraction is an essential technic to improve imaging quality in various radiological procedures. The limitations of subtraction, however, are well known. Blurred under-subtraction (BUS) method has been suggested to overcome and compensate these limitations. Ten cases of angiography were subtracted by conventional subtraction and BUS technic. Results of this study revealed that BUS method is simple to perform and imaging quality obtained by BUS is excellent. Comparing to conventional subtraction, BUS method has advantages. For example, BUS need no mask film or no immobilization of patient during examination. Improvement of imaging Qualify is achieved by edge enhancement, homogeneous blurring of background density and increasing contrast. With emphasis of its simplicity in technic, we would report that BUS method is a useful adjunct imaging technic in various radiological procedures.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제12권2호
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• pp.137-142
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• 2012

The temporal subtraction technique as one of computer aided diagnosis has been introduced in medical fields to enhance the interval changes such as formation of new lesions and changes in existing abnormalities on deference image. With the temporal subtraction technique radiologists can easily detect lung nodules on visual screening. Until now, two-dimensional temporal subtraction imaging technique has been introduced for the clinical test. We have developed new temporal subtraction method to remove the subtraction artifacts which is caused by mis-registration on temporal subtraction images of lungs on MDCT images. In this paper, we propose a new computer aided diagnosis scheme for automatic enhancing the lung nodules from the temporal subtraction of thoracic MDCT images. At first, the candidates regions included nodules are detected by the multiple threshold technique in terms of the pixel value on the temporal subtraction images. Then, a rule-base method and artificial neural networks is utilized to remove the false positives of nodule candidates which is obtained temporal subtraction images. We have applied our detection of lung nodules to 30 thoracic MDCT image sets including lung nodules. With the detection method, satisfactory experimental results are obtained. Some experimental results are shown with discussion.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권4호
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• pp.782-804
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• 2011

In video-based recognition systems, stationary cameras are used to monitor an area of interest. These systems focus on a segmentation of the foreground in the video stream and the recognition of the events occurring in that area. The usual approach to discriminating the foreground from the video sequence is background subtraction. This paper presents a novel background subtraction method based on a probabilistic approach. We represent the posterior probability of the foreground based on the current image and all past images and derive an updated method. Furthermore, we present an efficient fusion method for the color and edge information in order to overcome the difficulties of existing background subtraction methods that use only color information. The suggested method is applied to synthetic data and real video streams, and its robust performance is demonstrated through experimentation.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2004년도 춘계학술대회 논문집
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• pp.401-405
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• 2004

Column subtraction, originally proposed by Harche and Thompson(]994), is an exact method for solving large set covering, packing and partitioning problems. Since the constraint set of ship scheduling problem(SSP) have a special structure, most instances of SSP can be solved by LP relaxation. This paper aims at applying the column subtraction method to solve SSP which can not be solved by LP relaxation. For remained instances of unsolvable ones, we subtract columns from the finale simplex table to get another integer solution in an iterative manner. Computational results having up to 10,000 0-1 variables show better performance of the column subtraction method solving the remained instances of SSP than complex branch-and-bound algorithm by LINDO.

• 한국항해항만학회지
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• 제28권2호
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• pp.129-133
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• 2004

Column subtraction, originally proposed by Harche and Thompson(1994), is an exact method for solving large set covering, packing and partitioning problems. Since the constraint set of ship scheduling problem(SSP) have a special structure, most instances of SSP can be solved by LP relaxation This paper aim, at applying the column subtraction method to solve SSP which am not be solved by LP relaxation For remained instances of unsolvable ones, we subtract columns from the finale simplex table to get another integer solution in an iterative manner. Computational results having up to 10,000 0-1 variables show better performance of the column subtraction method solving the remained instances of SSP than complex branch and-bound algorithm by LINDO.

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2009년도 학술대회
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• pp.631-636
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• 2009

컴퓨터 비전 분야에서 전경을 추출하기 위한 영역 분할(segmentation) 방법에 대한 연구가 활발히 진행되어 왔다. 특히, 전경이 배제된 배경 영상과 현재 프레임의 차이를 이용하여 전경을 추출하는 배경 차분(background subtraction) 방법은 요구하는 계산량에 비해 우수한 품질의 전경 추출이 가능하므로 실시간 처리가 필요한 비전 시스템에 다양하게 응용되고 있다. 그러나 배경 차분 방법만을 이용하여서는 배경이 동적으로 변하는 환경에서 정확한 전경을 추출해 내지 못하는 단점이 있다. 본 논문에서는 정적인 배경과 동적인 배경이 공존하는 환경에서 영역 분할을 효과적으로 수행하는 방법을 제안한다. 제안된 방법은 정적인 배경 영역에 대해서는 기존의 배경 차분 방법을 이용하여 전경을 추출하고, 동적인 배경 영역에 대해서는 깊이 정보를 이용하여 전경을 추출하는 하이브리드 방식을 사용한다. 정적인 배경에 동적인 영상을 프로젝터로 투영하는 환경에서 제안된 방법의 효율성을 검증하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 하계종합학술대회논문집
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• pp.599-602
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• 1998

In this paper, a speech enhancement method based on phonemic properties and masking effect is propsoed. It is a modified type of spectral subtraction wherein the spectral sharpening process is exploited in unvoiced state considering the phonemic properties. The masking threshold is used to remove the residual noise. The proposed spectral subtraction shows similar performance as that of the classical spectral subtraction method in view of the SNR. But by the prposed scheme, the unvoiced sound region is shown to exhibit relatively less signal distortion in the enhanced speech.

• Journal of Electrical Engineering and Technology
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• 제10권1호
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• pp.372-378
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• 2015

Background subtraction is the first processing stage in video surveillance. It is a general term for a process which aims to separate foreground objects from a background. The goal is to construct and maintain a statistical representation of the scene that the camera sees. The output of background subtraction will be an input to a higher-level process. Background subtraction under dynamic environment in the video sequences is one such complex task. It is an important research topic in image analysis and computer vision domains. This work deals background modeling based on modified adaptive Gaussian mixture model (GMM) with three temporal differencing (TTD) method in dynamic environment. The results of background subtraction on several sequences in various testing environments show that the proposed method is efficient and robust for the dynamic environment and achieves good accuracy.

• 대한수학회보
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• 제45권3호
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• pp.437-444
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• 2008

As a weak form of a subtraction algebra, the notion of weak subtraction algebras is introduced, and its examples are given. A method to make a weak subtraction algebra from a quasi-ordered set is provided.