• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.589-592
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• 1999

Matching is a key problem in computer vision, image analysis and pattern recognition. In this paper a multiscale image matching algorithm by wavelet local extrema is proposed. This algorithm is based on the multiscale wavelet transform of the curvature which can utilize both the information of local extrema positions and magnitudes of transform results. This method has advantages in computational cost to a single scale image matching. It is also rotation-, translation-, and scale-independent image matching method. This matching can be used for the recognition of occluded objects.

• 제어로봇시스템학회논문지
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• 제16권4호
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• pp.313-318
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• 2010

This paper deals with the relationship between zeros and step response of the second and third order LTI (Linear Time Invariant) SISO (Single-Input and Single-Output) systems with complex poles. Although it has been known that the maximum number of local extrema is less than the number of zeros in the system with only real poles[8], some cases with complex poles are shown in this paper to have many local extrema. This paper proposes monotone nondecreasing conditions and describes the relationship between the transient response and the number of local extrema in step response with each region of zeros.

• 대한원격탐사학회지
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• 제22권4호
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• pp.275-284
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• 2006

Hyperion 영상의 노이즈는 주로 대기 효과와 센서의 기계오류, 신호변환 때문이다. 보정되지 않은 밴드, 중복 밴드, 모든 대기흡수에 영향을 많이 받는 밴드가 모두 제거되어도, 여전히 노이즈 밴드가 존재한다. 영상처리에 사용할 선명하고 안정된 밴드를 선택하기 위해 육안으로 영상을 간단하게 검사할 수 있지만, 이는 수동으로 이루어지는 비효율적이고 주관적인 방법이다 본 논문에서 우리는 노이즈 추정과 자동 밴드 선택을 위해 극단화소비 사용을 제안한다. 이를 위해 기존에 사용되던 SNR, 엔트로피와 극단화소비를 비교하였다. 첫째, 상대적으로 노이즈가 적은 ALI 영상에 Gaussian 노이즈, salt & pepper 노이즈, Speckle 노이즈를 부가하여 노이즈량과 각 통계량 사이의 관계를 살펴보았다. 둘째, Hyperion 영상에서 추출된 세 개 통계량에 대해 기대최대화 분석을 수행하여 자동으로 밴드를 선택하였다. Hyperion 데이터는 시각적 평가에 의해 5단계로 구분되어 평가자료로 사용되었다. 실험 결과에서 극단화소비가 Hyperion 영상의 밴드 선택에 효과적으로 사용될 수 있었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.404-406
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• 2002

In this paper, the method of image feature extraction is proposed. This method employ the energy field analysis, outlier removal algorithm and ring projection. Using this algorithm, we achieve rotation-translation-scale invariant feature extraction. The force field are exploited to automatically locate the extrema of a small number of potential energy wells and associated potential channels. The image feature is acquired from relationship of local extrema using the ring projection method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.683-686
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• 1988

In the recognition of similar patterns like profile contours of human faces, feature measure plays important role. We extracted effective and general feature by B-spline approximation. The nodes and vertices of the approximated curve are normalized and used as features. Since the features have both local property of curvature extrema and global property by B-spline approximation, they are superior to those of curvature extrema of the profile contour. For the image data of six sets of 56 persons, some of which are ill-made, averaged accuracy rate of 97.6 % is obtained in recognizing combinational 333 test samples.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2006년도 춘계학술발표회 논문집
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• pp.193-198
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• 2006

Among 242 Hyperion bands, there are 46 bands that contain completely no information and some other bands with various kinds of noise. It is mainly due to the atmosphenc absorption and the low signal-to-noise ratio. The visual inspection for selecting clean and stable bands is a simple practice, but is a manual, inefficient, and subjective Process. Though uncalibrated, overlapping, and all deep water absorption bands are removed, there still exist noisy bands. In this paper, we propose that the extrema ratio be measured for noise estimation and the unsupervised band selection be performed using the Expectation-Maximization algorithm. The Hyperion data were classified into 5 categories according to the image quality by visual inspection, and used as the reference data. The accuracy of the proposed method was compared with signal-to-noise ranking and entropy ranking. As a result, the proposed mettled was effective as preprocessing step for band selection.

• 제어로봇시스템학회논문지
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• 제15권8호
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• pp.804-811
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• 2009

This paper deals with the relationship between zeros and step response of the second and third order LTI(Linear Time Invariant) SISO(Single-Input and Single-Output) systems. As well known, if a system has a single unstable zero, it shows the step response with undershoot and, on the other hand, a stable zero slower than the dominant pole causes the system to have the step response with overshoot. Generally, in the case of a system with two unstable real zeros, it is known to have B type undershoot[7]. But there are many complex cases of the step response extrema corresponding to zeros location in third order systems. This paper investigates the whole cases depending on DC gains of the additive equivalence systems and they are to be classified by the region of zeros which are related to the shape of the step response. Moreover, monotone nondecreasing conditions are proposed in the case of complex conjugate zeros as well as the case of two stable zeros.

• 한국수학교육학회지시리즈A:수학교육
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• 제49권2호
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• pp.247-257
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• 2010

In this article an explanation of monotonicity of functions and the definition of local extrema in Korean highschool textbooks based on national curriculum(revised in 2007) are analyzed critically. On the basis of this analysis, we indicate some problems and propose its improvements.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2005년도 창립60주년 기념 추계 학술대회
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• pp.210.2-210.2
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• 2005

• 한국음향학회지
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• 제32권6호
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• pp.532-540
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• 2013

본 논문에서는 수동 소나의 광대역 에너지 탐지를 위하여 수신신호 강도 변화에 따른 가중치를 인가하는 기법을 제안한다. 광대역 에너지 탐지에 널리 사용되는 부대역 에너지 탐지 (Subband Energy Detection) 기법은 CED(Conventional Energy Detection) 기법에 비하여 다중신호 및 클러터 간섭에 강인하나, 수신신호에서 검출된 극값의 강도 변화에 따라 효율적인 가중치를 인가할 수 없어 탐지 성능을 저하 시킨다. 따라서 본 논문에서는 검출된 극값의 강도 변화에 따라 효율적으로 가중치를 인가하는 기법을 제안하였다. 시뮬레이션 및 황해 실 음향 데이터를 이용한 성능 비교, 칼만 필터를 이용한 추적시험 수행을 통하여 제안 기법의 탐지성능이 기존 기법에 비해 우수함을 관찰하였다.