• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제8권3호
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• pp.289-294
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• 2002

데이타로부터 유효한 음성 데이타를 추출하는 것은 음성 인식분야에서 중요하다. 본 논문의 음성 추출 기술은 빠른 연산이 가능하며 음성의 전처리 과정에 적합한 이산 웨이브렛 변환을 사용하고 있으며, 이산 웨이브렛 변환의 복수 해상도 해석 특징을 이용한 머징 알고리즘으로 유효한 음성을 추출하고 노이즈 제거를 동시에 구현한다. 머징 알고리즘은 음성만으로도 처리 매개변수를 결정할 수 있고 또한 시스템 잡음에 대하여서도 독립적이기 때문에, 유효 음성을 추출하는데 매우 효과적이다. 그리고 머징 알고리즘은 시스템 잡음에 대한 적응 특성을 갖고 탁월한 노이즈 분리 특성을 갖는다.

• Current Optics and Photonics
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• 제1권6호
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• pp.587-597
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• 2017

The extraction of the valid measurement region from the interference fringe pattern is a significant step when measuring gear tooth flank form deviation with grazing incidence interferometry, which will affect the measurement accuracy. In order to overcome the drawback of the conventionally used method in which the object image pattern must be captured, an improved segmentation approach is proposed in this paper. The interference fringe patterns feature, which is smoothed by the nonlinear diffusion, would be extracted by the structure tensor first. And then they are incorporated into the vector-valued Chan-Vese model to extract the valid measurement region. This method is verified in a variety of interference fringe patterns, and the segmentation results show its feasibility and accuracy.

• ETRI Journal
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• 제34권2호
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• pp.147-158
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• 2012

In this paper, we present a demodulation structure suitable for a reader baseband receiver in a passive radio frequency identification (RFID) environment. In a passive RFID configuration, an undesirable DC-offset phenomenon may appear in the baseband of the reader receiver, which can severely degrade the performance of the extraction of valid information from the received tag signal. To eliminate this DC-offset phenomenon, the primary feature of the proposed demodulation structures for the received FM0 and Miller subcarrier signals is to reconstruct the signal corrupted by the DC-offset phenomenon by creating peak signals from the corrupted signal. It is shown that the proposed method can successfully detect valid data, even when the received baseband signal is distorted by the DC-offset phenomenon.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.51-55
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• 1997

This study is devote to developing navigation filter for detecting sensor failure in multi-sensor navigation system. In multi-sensor navigation system, Kalman filter is generally used to fuse data of each sensors. Sensor failure is fatal in case that the sensor is used as external measurement of Kalman filter therefore detection and recovery of sensor failure is one the important feature of navigation filter. Generally each sensors have its specific feature in measuring navigational information. Fuzzy theory is proposed to detect external sensor failure and provide valid external measurement to Kalman filter avoiding filter divergence and instability. This idea is applied to Autonomous Underwater Vehicle(AUV) which has two navigation sensor i. e self contained inertial sensor and acoustic external sensor. 2 dimensional simulation result shows acceptable failure detection and recovery

• 한국정보전자통신기술학회논문지
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• 제5권1호
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• pp.20-25
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• 2012

표면근전도의 중앙주파수 특징을 이용하여 근지구력시간에 대한 남녀 성별차별을 구분할 수가 있다. 중앙주파수는 근육의 피로속도를 측정하는데 주로 사용하는 인자이다. 본 연구에서는 상완이두근의 등장성 운동을 통한 근전도의 성별차이를 알아보았다. 등장성운동은 피실험자가 근육피로가 피곤해 질 때까지를 측정하였다. 남녀 성별차이는 근지구력시간에 대한 중앙주파수의 선형회귀선의 기울기로 구분되어지는 특성을 보였다.

• Wind and Structures
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• 제18권6호
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• pp.651-668
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• 2014

Wind tunnel tests are conducted to investigate the wind loads on vertical fixed-roof cylindrical tanks with a very low aspect ratio of 0.275, which is a typical ratio for practical tanks with a volume of $100,000m^3$. Both the flat-roof tank and the dome-roof tank are investigated in present study. The first four moments of the measured wind pressure, including the mean and normalized deviation pressure, kurtosis and skewness of the pressure signal, are obtained to study the feature of the wind loads. It is shown that the wind loads are closely related to the behavior of flow around the structure. For either tank, the mean wind pressures on the cylinder are positive on the windward area and negative on the sides and the wake area, and the mean wind pressures on the whole roof are negative. The roof configurations have no considerable influence on the mean pressure distributions of cylindrical wall in general. Highly non-Gaussian feature is found in either tank. Conditional sampling technique, envelope method, and the proper orthogonal decomposition (POD) analysis are employed to investigate the characteristics of wind loads on the cylinder in more detail. It is shown that the patterns of wind pressure obtained from conditional sampling are similar to the mean pressure patterns.An instantaneous pressure coefficient can present a wide range from the maximum value to the minimum value. The quasi-steady assumption is not valid for structures considered in this paper according to the POD analysis.

• 한국컴퓨터정보학회논문지
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• 제22권5호
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• pp.21-28
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• 2017

As technology related to digital imaging equipment is developed and generalized, digital imaging system is used for various purposes in fields of society. The object tracking technology from digital image data in real time is one of the core technologies required in various fields such as security system and robot system. Among the existing object tracking technologies, cam shift technology is a technique of tracking an object using color information of an object. Recently, digital image data using infrared camera functions are widely used due to various demands of digital image equipment. However, the existing cam shift method can not track objects in image data without color information. Our proposed tracking algorithm tracks the object by analyzing the color if valid color information exists in the digital image data, otherwise it generates the lightness feature information and tracks the object through it. The brightness feature information is generated from the ratio information of the width and the height of the area divided by the brightness. Experimental results shows that our tracking algorithm can track objects in real time not only in general image data including color information but also in image data captured by an infrared camera.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권1호
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• pp.347-370
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• 2019

In the computer-aided detection (CAD) system of pulmonary nodules, a high false positive rate is common because the density and the computed tomography (CT) values of the vessel and the nodule in the CT images are similar, which affects the detection accuracy of pulmonary nodules. In this paper, a method of automatic detection of pulmonary nodules based on multi-scale enhancement filters and 3D shape features is proposed. The method uses an iterative threshold and a region growing algorithm to segment lung parenchyma. Two types of multi-scale enhancement filters are constructed to enhance the images of nodules and blood vessels in 3D lung images, and most of the blood vessel images in the nodular images are removed to obtain a suspected nodule image. An 18 neighborhood region growing algorithm is then used to extract the lung nodules. A new pulmonary nodules feature descriptor is proposed, and the features of the suspected nodules are extracted. A support vector machine (SVM) classifier is used to classify the pulmonary nodules. The experimental results show that our method can effectively detect pulmonary nodules and reduce false positive rates, and the feature descriptor proposed in this paper is valid which can be used to distinguish between nodules and blood vessels.

• Wind and Structures
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• 제19권3호
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• pp.249-270
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• 2014

Through comparing the mean wind profiles observed overland during the passages of four typhoons, and the gradient wind speeds calculated based on the sea level pressure data provided by a numerical model, the present paper discusses, (a) whether the gradient balance is a valid assumption to estimate the wind speed in the height range of 1250 m ~ 1750 m, which is defined as the upper-level mean wind speed, in a tropical cyclone over land, and (b) if the super-gradient feature is systematically observed below the height of 1500 m in the tropical cyclone wind field over land. It has been found that, (i) the gradient balance is a valid assumption to estimate the mean upper-level wind speed in tropical cyclones in the radial range from the radius to the maximum wind (RMW) to three times the RMW, (ii) the super-gradient flow dominates the wind field in the tropical cyclone boundary layer inside the RMW and is frequently observed in the radial range from the RMW to twice the RMW, (iii) the gradient wind speed calculated based on the post-landfall sea level pressure data underestimates the overall wind strength at an island site inside the RMW, and (iv) the unsynchronized decay of the pressure and wind fields in the tropical cyclone might be the reason for the underestimation.

• 대한전자공학회논문지SP
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• 제43권4호
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• pp.87-95
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• 2006

본 논문에서는 얼굴 영상의 에너지 분포 특성을 이용한 새로운 특정추출 방법을 제안한다. 제안된 방법은 얼굴 영상의 에너지 확률과 에너지 랩을 이용해서 데이터 차원이 축소된 유효정보의 추출 및 유효정보의 LDA 해석에 기반을 둔다. 일반적으로, 얼굴 영상은 고유한 에너지 분포 특성을 가지고 있다. 그러나 기존의 많은 DCT 기반 방법들은 이러한 얼굴 영상의 특성을 효과적으로 이용하지 못하는 단점이 있다. 제안된 방법은 이러한 기존 방법의 단점을 개선하기 위해 다음의 3단계 방법을 사용한다. 먼저, DCT 도메인에서 얼굴의 에너지 확률 개념을 정의하고, 이러한 에너지 확률로부터 얼굴의 에너지 맵을 생성한다. 마지막으로, 에너지 확률 지도에 위치한 주파수 계수들에 대한 LDA 적용 및 해석을 통하여 특정 벡터 추출 및 인식을 수행한다. 제안된 방법은 ETRI 데이터베이스에서 96.8%, ORL 데이터베이스에서 100%의 인식률을 보인다. 실험을 통하여 인식 성능의 개선뿐만 아니라, 특정 벡터의 차원 축소에도 효과가 있음을 알 수 있다.