• 한국음향학회지
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• 제29권2호
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• pp.133-140
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• 2010

연속 심음신호로부터 추출한 새로운 시간영역에서의 특징들을 추가하여 심장질환 분류의 성능을 개선한다. 기존에 사용되고 있는 켑스트럼 영역 특징인 멜주파수 켑스트럼 계수 (MFCC)에 심음 포락선, 심잡음 확률벡터, 심잡음 진폭값 변동으로 구성된 새로운 3종류의 시간영역 특징을 추가한다. 심장 질환 분류 및 검출 실험에서, 시간영역 특징의 분류 정확도에 대한 기여도를 평가하고 순차적 특징선택 방식을 이용하여 시간영역 특징을 선택한다. 선택된 특징들은 다층 퍼셉트론(MLP), support rector machine (SVM), extreme learning machine (ELM)와 같은 신경회로망 패턴 분류기에 대하여 의미있고 일관되게 분류 정확도를 개선함을 보여준다.

• 전기학회논문지
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• 제56권6호
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• pp.1139-1143
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• 2007

For the possible application of monitoring or diagnosing heart sounds in an ubiquitous healthcare environment. a small and light electro-stethoscope that can be attached in human body should be exploited. With this aim, this study proposes a new style of electro-stethoscope device that is composed of four hardware modules in wearable style. For this ambulatory heart sound collecting device, the several tests must be performed to check portability and material capability for collecting heart sounds. It turned out to be that the multi-channel electro-stethoscope can detect heart sound signals well even if it is not pinpointed in the accurate stethoscope point on a heart. Consequently, our ambulatory electro-stethoscope hardware system can be applied to monitor or diagnose abnormal heart sounds in the ubiquitous healthcare system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.101-102
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• 2007

Heart diseases are critical and should be detected as soon as possible. A stethoscope is a simple device to find cardiac disorder but requires keen experiences in heart sounds. We evaluate a cardiac disorder classifier by using heart sounds recorded by a digital wireless stethoscope developed in this work. The classifier uses hidden Markov models with circular state transition to model the heart sounds. We train the classifier using two kinds of data: One recorded by using our stethoscope and the other sampled from a clean heart sound database. In classification experiments using 165 sound clips, the classifier shows the classification accuracy of 82% in classifying 6 cardiac disorder categories.

• 융합신호처리학회논문지
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• 제2권1호
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• pp.108-112
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• 2001

Heart sound contains rich information regarding the dynamics of the heart and the auscultation has been a first choice of routine procedures for diagnosis of the heart. However, heart sounds captured using a conventional stethoscope are not often loud or clear enough for doctors to precisely classify their characteristics, especially, under the noisy environments of the hospital. A simple auscultation device that removed shortcomings of the conventional stethoscope was constructed in the study. The device employed a polymer based adherent differential output sensor which was on contact with skin through a coupling medium and appropriated electronic circuits for signal amplification and conditioning An ordinary headphone is taken to hear the captured heart sounds and the volume can be adjusted to hear well. It is also possible that the device sends the captured heart sound signals to a PC where the signals are further processed and viualized.

• 융합신호처리학회논문지
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• 제16권4호
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• pp.134-138
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• 2015

본 논문은 심장질환을 비침습적 방법으로 빠르고 쉽게 진단할 수 있도록 심음을 이용하는 방법에 대한 가능성을 찾는 것이다. 일반적으로 심음의 분류를 위하여 심음을 분리한 후에 특징파라미터를 추출하는 과정을 거치지 않고, 심음 분리에 사용되는 Shannon 엔트로피로 정규화하여 신경회로망의 입력으로 사용하였다. 심장질환에 따른 심잡음 분류를 위하여 Scaled conjugate gradient 역전파 알고리즘을 이용하여 신경회로망 분류기를 구현하였다. 정상 심음과 심장 질환의 경우 5가지를 포함하여 6종류의 심잡음에 대하여 분류가 가능함을 확인하였다.

• 융합신호처리학회 학술대회논문집
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• 한국신호처리시스템학회 2000년도 하계종합학술대회논문집
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• pp.185-188
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• 2000

Heart sound contains rich information regarding the dynamics of the heart and the auscultation has been a first choice of routine procedures for diagnosis of the heart. However, heart sounds captured using a conventional stethoscope are not often loud or clear enough for doctors to precisely classify their characteristics, especially, under the noisy environments of the hospital. A simple auscultation device that removed shortcomings of the conventional stethoscope was constructed in the study. The device employed a polymer based adherent differential output sensor which was on contact with skin through a coupling medium and appropriated electronic circuits for signal amplification and conditioning. An ordinary headphone is taken to hear the captured heart sounds and the volume can be adjusted to hear well. It is also possible that the device sends the captured heart sound signals to a PC where the signals are further processed and viualized.

• 한국정보통신학회논문지
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• 제17권12호
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• pp.3001-3008
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• 2013

심음도(PCG, Phonocardiogram) 분석을 이용하여 심장의 판막과 관련된 질환을 진단하기 위해서는 먼저 심음 분할을 위해 심음의 주성분인 S1과 S2를 정확하게 찾아야 한다. 본 논문에서는 심음포락선의 모멘트 특성을 분석하고 이를 심음 분할에 적용하였다. 기존의 2차 모멘트를 이용한 심음 분할의 문제점을 분석하고, 심잡음이 있더라도 심음 주성분의 검출이 용이한 3차 모멘트에 기반한 방법을 제안하였다. 심음포락선은 심음 신호의 단구간 에너지를 이용하였으며, 3차 모멘트 궤적의 기울기 정보를 이용하여 심음 주성분을 검출하고 지속시간을 게이팅(gating) 하였다. 다양한 심잡음이 포함된 심음 신호에 대한 실험을 통해 제안한 방법이 기존의 2차 모멘트 기법보다 심잡음의 영향을 적게 받고 심음 주성분의 구간을 정확하게 검출 할 수 있음을 보였다.

• 대한전기학회논문지:시스템및제어부문D
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• 제50권5호
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• pp.241-246
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• 2001

The conventional stethoscope can not store its stethoscopic sounds. Therefor a doctor diagnoses a patient with instantaneous stethoscopic sounds at that time, and he can not remember the state of the patient's stethoscopic sounds on the next. This prevent accurate and objective diagnosis. If the electronic stethoscope, which can store the stethoscopic sound, is developed, the auscultation will be greatly improved. This study describes an amplifier for electronic stethoscope system that can extract heart sounds of fetus as well as adult and alow us hear and record the sounds. Using the developed stethoscopic amplifier, clean heart sounds of fetus and adult can be heard in noisy environment, such as a consultation room of a university hospital, a laboratory of a university. Surprisingly, the heart sound of a 22-week fetus was heard through the developed electronic stethoscope. Pitch detection experiments using the detected heart sounds showed that the signal represents distinct periodicity. It can be expected that the developed electronic stethoscope can substitute for conventional stethoscopes and if proper analysis method for the stethoscopic signal is developed, a good electronic stethoscope system can be produced.

• Journal of Chest Surgery
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• 제22권4호
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• pp.589-593
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• 1989

The frequency spectrum of the metallic closing sound and its loudness were measured by non invasive techniques in 66 patients. They had examined a total of 7 Carbomedics valve, 10 Duromedics valve, 11 St. Jude heart valve in mitral position and 8 Carbomedics, 10 Duromedics, 20 St. Jude heart valve prostheses functioning normally in aortic position. Statistical comparison of the loudness from sound produced by the three valves in each position, the following; The Carbomedics valve has the lowest average loudness, followed by the St. Jude medical valve, and finally the Edward Duromedics valve. And we analysis the changing factor of the loudness of valve sound, only the velocity of the flow through the valve influenced to the valve sound.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 G
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• pp.2486-2488
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• 1998

In this paper, Prameters esimated t using AR model in order to approach linearly the heart sound which include the nonlinear characteristic from the characteristics based on a statistical theory. The parameters which is figured out using AR model is a very important information which show the characteristic heart sound In this paper parameters estimated using autocorrelation method and order selected by proposed Akaike[6] method. Compared the similirities of the spectrums between estimated by using AR model and estimated by using FFT method.