• Journal of the Institute of Convergence Signal Processing
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• v.5 no.1
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• pp.1-5
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• 2004

A new method for the estimation of pitch-frequency contour of voiced speech is presented. The method is based on the double application of Kaiser's energy operator［1］, which has the capabilities of extracting amplitude and frequency of a sinusoidal waveform. According to the modulation model, a vowel can be represented by a combination of damped sinusoids representing formants, modulated by pitch pulses. Therefore, the amplitude envelope of each of the components will give a pitch-like waveform and the pitch can be obtained by averaging the frequencies of this waveform. The first part is the same as Gopalan's approach［9］, but by substituting the LPC based spectral analysis with the second application of energy operator, the algorithm becomes very simple and can be processed on-line. Although the estimation is rather coarse, the suggested algorithm can be useful for getting a general sketch of pitch contour on-line.

• Korean Journal of Remote Sensing
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• v.29 no.4
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• pp.361-373
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• 2013

The monitoring of urban area, target detection and building reconstruction have been actively studied and investigated since high resolution X-band SAR images could be acquired by airborne and/or satellite SAR systems. This paper describes an efficient approach to reconstruct artificial structures (e.g. apartment, building and house) in urban area using high resolution X-band SAR images. Building footprint was first extracted from 1:25,000 digital topographic map and then a corner line of building was detected by an automatic detecting algorithm. With SAR amplitude images, an initial building height was calculated by the length of layover estimated using KS-test (Kolmogorov-Smirnov test) from the corner line. The interferometric SAR phases were simulated depending on SAR geometry and changable building heights ranging from -10 m to +10 m of the initial building height. With an interferogram from real SAR data set, the simulation results were compared using the method of the phase consistency. One of results can be finally defined as the reconstructed building height. The developed algorithm was applied to repeat-pass TerraSAR-X spotlight mode data set over an apartment complex in Daejeon city, Korea. The final building heights were validated against reference heights extracted from LiDAR DSM, with an RMSE (Root Mean Square Error) of about 1~2m.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.8
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• pp.1498-1502
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• 2007

There have been many different definitions of energy functions as the second statistics of a signal. In this paper, using the higher order differential energy function, we propose an algorithm separating the amplitude and frequency components in a discrete sinusoidal signal. The proposed amplitude and frequency estimation methods have less computational requirement than the existing methods. It also shows large computational advantage over the root mean square (RMS) calculation of a signal. The proposed methods can be used in the detection of abnormal events in signals on the power line. Computer simulations show that proposed frequency estimation method can detect the presence of voltage increase or decrease for a short period of time. Also, the proposed estimation methods have been compared with existing methods in terms of estimation error variance.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.10a
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• pp.284-288
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• 1995

최근 애매성이 수반되는 정보를 Zadeh는 멤버쉽함수(membership function)를 이용하여 새로운 정보처리 방식으로서 퍼지이론을 제안하였고, 그후 의료계에서도 퍼지이론을 도입한 진단법들이 제안되었다. 회전기계의 이상진단법으로는 주파수득점법(Point counting method), 퍼지역연산법(Inverse method of fuzzy theory)등이 보고되고 있으며, 저자들도 퍼지이론을 이용하여 구름베어링의 결함진단, 회전기계의 간이 이상진단법등을 보고하였다. 이들은 주로 진동주파수의 스펙트럼 데이터 만을 이용하고 있고, 다른 많은 데이터를 복합적으로 이용할 수 없다. 이 때문에 주로 소규모 문제의 간이진단에서는 효과적이나 진단대상이 복잡하고 대규모로 되면 보다 정확한 원인 추정이 곤란하게 된다. 또한 수치데이터만을 취급할 수 있으므로 진동전문가가 진단에 이용하는 각종의 수치화 될 수 없는 데이터(언어적인 정보)가 취급될 수 없다. 따라서 이들의 진단법은 개략적인 진단은 가능하나 상세한 원인까지는 진단할 수 없는 단점이 있다. 회전기계의 이상판단시 참고가 되는 각종 정보로는 주로 진동진폭의 크기, 진폭과 위상의 변화, 진폭의 변화, 진동파형, 진동벡터의 시간변화 등이 있고, 이들은 수치적으로 표현할 수 있는 계량데이터와 판단의 경계가 불명확한 언어정보(범위데이터)로 나눌 수 있다. 후자는 애매성(fuzziness)을 많이 포함하고 있으며, 엄밀히 측정되는 수치데이터에서도 퍼지성을 가지고 있다. 이러한 언어적인 정보의 애매성을 퍼지추론에서는 [수치적 진리치](numeric truth)와 [언어적 진리치](linguistic truth)의 개념으로 표현하게 되었다. 수치적 진리치는 확실함의 척도를 [0,1] 사이의 수치를 이용하여 표현하고 있으며, 이 수치는 소견의 확실도로서 가능성을 표현한 것이다. 예를 들면, 진동진폭 스펙트럼상에 2X 성분이 상당히 크게 나타나 정렬불량의 가능성이 0.7 정도라고 판정하는 것 등은 이러한 수치적진리치를 이용하는 방법이다. 그러나 상기의 수치적 표현만으로는 확실도를 한개의 수치로서 대표하게 하는 것은 진단의 정밀도에 문제가 있을 것으로 생각된다. 따라서 언어적진리치가 도입되어 [상당히 확실], [확실], [약간 확실] 등의 언어적인 표현을 이용하여 애매성을 표현하게 되었다. 본 논문에서는 간이진단 결과로부터 추출된 애매한 진단결과중에서 가장 가능성이 높은 이상원인을 복수로 선정하고, 여러 종류의 수치화할 수 없는 언어적(linguistic)인 정보ㄷㄹ을 if-then 형식의 퍼지추론으로 종합하는 회전기계의 이상진단을 위한 정밀진단 알고리즘을 제안하고 그 유용성을 검토한다.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.335-338
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• 2002

본 연구에서는 주파수 영역에서의 확산 스펙트럼 방식을 이용한 오디오 워터마킹 기법을 사용하고 있다. 워터마크 삽입은 오디오 신호를 MCLT(Modulated Complex Lapped Transform)로 분석한 후, 특정 주파수 영역의 진폭에 삽입되며 추출은 상관도를 이용하여 추출하게 된다. 워터마크 삽입은 44.1 kHz의 음악에 80 bits의 정보가 4초 단위로 반복적으로 삽입되며, 추출에서는 무작위로 추출된 8초 분량의 오디오 신호로부터 80 bits 비트 열과의 상관도를 계산하여 선정된 문턱 값을 초과하게 되면 워터마크가 존재하는 것으로 판단하게 된다 피치 스케일에 대응하기 위하여 120개 정도의 탐색을 수행하며, 시간 스케일에 대응하기 위하여 상관도의 지역 최대 점을 추출하고, 이러한 지역 최대 점들로부터 추출된 비트 열과 실제 비트 열과의 상관도를 계산하게 된다. 그러나 추출된 비트 열은 삽입 에러와 삭제 에러를 가질 수 있기 때문에 이러한 비트 열과의 최대 상관도를 구하기 위하여 본 연구에서는 동적계획법에 의한 최대 상관도 추출 알고리즘을 제시한다. 제안된 방법은 피치 및 시간 스케일링 변환 뿐만 아니라, 오디오 압축에도 견고함을 보인다.

• Korean Journal of Food Science and Technology
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• v.39 no.1
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• pp.88-93
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• 2007

The preventive effect of Lentinus edodes extract (LE) against constipation was studied in rats. Rats were pretreated with LE contained in drinking water at the concentration of 10%, 20% and 40% over 30 days. Constipation was induced by subcutaneous injection of loperamide (4 mg/kg/day) 3 days prior to sacrifice. Treatment of loperamide resulted in decreases in the number and wet weight of fecal pellets, and increase in the number of fecal pellet in the distal colon and cecocolon weight. In contrast, the number and wet weight of fecal pellets were increased, and the number of fecal pellet in the distal colon and the cecocolon weight were decreased in LE-pretreated groups compared to the loperamide-treated group. Blood parameters such as white blood cell, red blood cell, hemoglobin, hematocrit, platelet, mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration, and serum alanine transaminase, aspartate aminotransferase and alkaline phosphatase activities, and blood urea nitrogen and creatinine values were not significantly different between the groups. In addition, LE (0.5 mg/mL) increased spontaneous contractile activity, which was reduced by atropine or loperamide in isolated rat ileum. Theses results suggest that the improvement of constipation symptoms in LE-pretreated rats resulted from a stimulatory effect of LE on intestine contractile activity.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.4
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• pp.349-358
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• 2019

This paper aimed at collecting sensor signals to extract characteristic parameter of the rotor. A vibration test rig has been developed to perform model tests. Signal characteristics were analyzed when driving normally. Envelope FFT Analysis is used to extract vibration components caused by periodic impacts from other vibration factors. Signal analysis was performed when load changes were given to speed sensors and vibration test rigs that show low frequency characteristics of the rotor and signal analysis according to rotational speed. The acceleration signal measured in the bearing housing has a small amplitude and produces only the rotational frequency component and harmonic component of the motor. As the number of rotations increases, the amplitude of acceleration can be seen. As the rotational speed increases, it can be seen that there is a difference in the shape of the original data and compared with the acceleration FFT graph, it can be seen that the noise is strong at low frequencies and the corresponding rotational frequency components are clearly represented. It can be seen that changing the load does not increase the main rotational frequency component.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.4
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• pp.825-832
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• 2014

Previous works for detecting arrhythmia have mostly used nonlinear method such as artificial neural network, fuzzy theory, support vector machine to increase classification accuracy. Most methods require accurate detection of P-QRS-T point, higher computational cost and larger processing time. Even if some methods have the advantage in low complexity, but they generally suffer form low sensitivity. Also, it is difficult to detect PVC accurately because of the various QRS pattern by person's individual difference. Therefore it is necessary to design an efficient algorithm that classifies PVC based on QRS pattern in realtime and decreases computational cost by extracting minimal feature. In this paper, we propose PVC classification based on QRS pattern using QS interval and R wave amplitude. For this purpose, we detected R wave, RR interval, QRS pattern from noise-free ECG signal through the preprocessing method. Also, we classified PVC in realtime through QS interval and R wave amplitude. The performance of R wave detection, PVC classification is evaluated by using 9 record of MIT-BIH arrhythmia database that included over 30 PVC. The achieved scores indicate the average of 99.02% in R wave detection and the rate of 93.72% in PVC classification.

• Geophysics and Geophysical Exploration
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• v.12 no.1
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• pp.143-153
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• 2009

Using a discrete wavenumber method, we examine the effects on Logging-While-Drilling (LWD) logs when a mismatch exists between the amplitudes or generating times of the signals from individual monopoles in a LWD multipole source. An amplitude-mismatched LWD dipole/quadrupole source produces non-dipole/non-quadrupole modes as well as flexural and screw modes. The strongest of non-dipole/non-quadrupole modes is the Stoneley mode, whose amplitude increases with increasing mismatch. However, we can recover the flexural mode signals by A-C processing, and the screw mode by A-B+C-D processing, respectively. The Stoneley mode, which has the same amplitude at the same radial distance from the borehole axis, is cancelled out by A-C and A-B+C-D processing as long as the tool is placed at the centre of the borehole. The responses from a time-mismatched LWD multipole source look like the summation of responses by two or four monopole sources off the borehole axis. However, we can avoid the misinterpretation of the formation velocities by referring to the computed dispersion curves, which are independent of the arrival times of the modes, on the frequency semblance plot.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09b
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• pp.114-117
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• 2003

본 논문에서는 사용자가 음악을 직접 선곡하지 않고 락, 트로트, 댄스, 힙합, 발라드 등 5가지의 장르 중 사용자가 선호하는 음악의 장르를 추천하는 시스템을 구현하였다. 실시간으로 연주되는 음악에서 Bass Drum 신호를 추출ㆍ분석하여, 기본적으로 한 마디에 소요되는 시간, 주법, 진폭 등 세가지 파라메터를 이용하여 5가지 장르로 분류하였다 선택 곡 수와 들은 시간으로 퍼지 추론을 통해 각 장르에 대한 사용자 만족도를 평가한다. 평가된 만족도에 의해 사용자가 선호하는 장르의 음악을 제공하는 시스템을 제안한다.