• Smart Media Journal
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• v.7 no.4
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• pp.90-98
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• 2018

A Multilinear LDA Method of Tensor Representation for ECG Signal Based Individual Identification Electrocardiogram signals, included in the cardiac electrical activity, are often analyzed and used for various purposes such as heart rate measurement, heartbeat rhythm test, heart abnormality diagnosis, emotion recognition and biometrics. The objective of this paper is to perform individual identification operation based on Multilinear Linear Discriminant Analysis (MLDA) with the tensor feature. The MLDA can solve dimensional aspects of classification problems in high-dimensional tensor, and correlated subspaces can be used to distinguish between different classes. In order to evaluate the performance, we used MPhysionet's MIT-BIH database. The experimental results on this database showed that the individual identification by MLDA outperformed that by PCA and LDA.

• Proceedings of the Korean Society of Computer Information Conference
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• 2013.07a
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• pp.355-356
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• 2013

심장의 활동을 전기적 변위로 표현되는 심전도 신호는 심장병 진단에 중요한 임상적 파라미터들을 제공한다. 특히 심전도 신호에서 P, QRS Complex,, T 특징점들로 대표되는 파형 변곡점들의 시간상 위치와 크기 및 형태학적 모양은 심장의 이상 리듬을 나타내는 부정맥여부를 검출하는데 핵심적인 역할을 한다. 본 연구에서는 특히 QRS complex 구간에 대한 첨도치의 연산 해석을 통하여 정상적인 심전도 리듬과 심실조기수축 부정맥 리듬을 구분하는 방법을 제시하고 또한 스마트폰을 기반으로 하는 심전도 모니터링 시스템에 적용하고자 하였다.

• The Korean Journal of Zoology
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• v.36 no.3
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• pp.319-328
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• 1993

All vertebrates other than lampreys exhibit multiple loci encoding lactate dehydrogenase (EC 1.1.1.27,LDH). From the result shown by cellulose acetate and starch gel electrophoresis, the lampreys were-reported to have only one isozyme. However in our results the LDH of skeletal muscle, heart and kidney in Lampetra japonica were separated into three isozymes and that of liver was separated into two isozymes by polyacrylamide gel electrophoresis. The LDH of skeletal muscle and heart were separated into four isozymes and that of liver was separated into two isozymes by polyacrylamide gel isoelectric focusing (PAGlEF). The LDH of skeletal muscle were separated into four isozymes through the chromatofocusing. The molecular weight of LDH isozymes in skeletal muscle was approximately estimated to be 140,000 by Sephadex G-200 gel filtration. The LDH isozymes of skeletal muscle, heart and liver were inhibited by pyruvate to the nearly similar degree. And the degree of inhibition by pyruvate showed the value between LDH A$_4$and LDH B$_4$isozyme. And the LDH isozymes in heart, liver and skeletal muscle were thermostable. The results mentioned above indicate that the LDH isozyme in lamprey (Lampetra japonica) has not one isozyme but isozymes. And it is also found out that the two structures of their subunits are similar each others.

• Journal of Biomedical Engineering Research
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• v.19 no.2
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• pp.163-170
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• 1998

The ultimate goal of total artificial heart is permanent substitute for a failed heart in a patient without any other therapeutic modality. Until now, infection has been the main problem related to the mechanical circulatory support system. The best way to solve this catastrophic complication and to improve the quality of life of TAH patients in terms of tethering must be implantation of TAH totally. The EH-TAH has been developed in NCVC from 1987 for this purpose. The system consists of an energy converter and pumps, which are designed to be placed in abdomen and pericardial space separately for a good anatomical fit. To evaluate the anatomical fit and hemodynamic performance of the EH-TAH, in vivo test was done. General condition of the animal and hemodynamic status had been stable until the TAH stopped on the 11th pumping day. The estimated cardiac output was about 7.7L/min. The values of mean aortic pressure, left and right atrial pressure were 93$\pm$10, 19$\pm$3 and 15$\pm$4 mmHg, respectively. The correlation coefficient between left and right atrial pressure was 0.96, which represents the dynamic function of the interatrial shunt in controlling left-right imbalance of cardiac output. During pumping days, the temperature on the surface of actuator had been maintained at 39.7$\pm$0.4$^{\circ}C$, less than 1$^{\circ}C$ higher than the rectal temperature. The TAH stopped on the 11th day due to mechanical problems. We concluded that the EH-TAH possessed satisfactory basic performance including anatomic fit and hemodynamic adequacy, although there were several mechanical problems to be solved yet.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2683-2684
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• 2004

심전도는 심장의 기능을 나타내는 중요한 생체전기신호의 일종이다. 이 논문에서는 Bluetooth 무선 규격을 사용하여 PC나 PDA로 송신이 가능한 휴대형 심전도 측정장치를 개발하였다. 개발된 시스템은 다채널 심전도를 측정하여 무선으로 전송하여 mobile device (PDA)나 PC 등에 실시간 디스플레이가 가능하다. 무선 전송에서 Bluetooth 규격을 사용함으로써 소형화 및 다중 채널로의 확장이 용이하고, 서로 다른 기기간의 간섭을 배재 할 수 있었다. 무선 전송기능과 이동성을 갖추고 있어 헬스기기나 실버의료기기 등 다양한 응용에 적용이 기대된다.

• Journal of Life Science
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• v.20 no.5
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• pp.723-728
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• 2010

The effect of abdominal respiration on electrocardiogram readings was examined using a 12-lead ECG in healthy young adults. Ten males and ten females without any cardiac and/or pulmonary problems participated in this study. ECG readings during periods of abdominal respiration and thoracic respiration were compared using a paired t-test. Results showed that the PR interval was longer in males compared to females during the period of abdominal respiration (p<0.05). There were no differences in amplitudes of the P, R, T waves, QTc, and degree of P axis between abdominal respiration and thoracic respiration in both male and female subjects. However, degrees of QRS axis in male subjects (p<0.05) and T axis (p<0.05) in female subjects were increased during the abdominal respiration. Therefore, abdominal respiration may cause positive electrical axis changes in the depolarization and relaxing re-polarization of the ventricles.

• Proceedings of the Korean Biophysical Society Conference
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• 1999.06a
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• pp.22-23
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• 1999

Voltage-gated $K^{＋}$ channels represent the most complex group of ion channel genes expressed in cardiovascular system. The human Kv1.5 channel (hKv1.5) represents the $I_{Kur}$ repolarizing current in atrial myocytes. The hKv1.5 channel is functionally modulated by the Kv$\beta$1.3 subunit, which converts it from a delayed rectifier to a channel with rapid inactivation and enhanced voltage sensitivity.(omitted)d)

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2003.11a
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• pp.449-467
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• 2003

뇌전도(EEG), 심전도(ECG) 와 같은 생체 전기신호는 카오스적 특성을 가지고 있으므로, 신호특성 분석에 비선형 도구를 사용하므로 의미있는 정보를 얻을 수 있다. 분석하는 데에는 주파수 특성, 변이 특성과 같은 생체시스템의 상태를 검증하는 방법이 주로 이용되어 왔다. 이에 본 연구에서는 심장 맥파의 RR 간격의 값을 획득하여 비선형 분석하는 도구로 Hurst Exponent 값의 변화를 모델화 하여 두 개의 비교대상 집단을 대상으로 차별성을 검출하는데 그 목적이 있다.

• Journal of Chest Surgery
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• v.33 no.12
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• pp.988-990
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• 2000

흉강경을 이용한 교감신경다발 차단술은 다한증 치료에 아주 효과적이다. 술 후 유미흉과 같은 합병증은 발생은 적으나 아주 위험할 수 있다. 흉관 근접 부위의 좌측 2번째에서 4번째 흉부 교감신경다발 차단술 후 발생한 유미흉을 흉강경을 이용한 전기 응고법으로 치료하였기에 보고하는 바이다.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.1085-1087
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• 2015

본 논문에서는 심장의 전기활성도를 반영하는 ECG 신호 중 일부를 명세한다. 꾸준히 축적되었고 통용되는 ECG 신호의 비정형 명세를 정형 명세로 바꾸는 과정에서 선형 시제 논리보다 시간을 다루는 명세 및 양적 평가에 유리한 신호 시제 논리(Signal Temporal Logic)를 사용한다. ECG 신호를 감지했다는 가정하에 특징점을 추상화하여 신호를 맹세했고, 양적으로 평가해주는 모델 기발 실시간 ECG 모니터링 시스템의 신속한 개발 필요성을 제시한다.