• Proceedings of the Optical Society of Korea Conference
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• 2002.11a
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• pp.188-189
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• 2002

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.12
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• pp.2655-2663
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• 2011

Several algorithms have been developed to detect AF which rely either on the form of P waves or the based on the time frequency domain analysis of RR variability. However, locating the P wave fiducial point is very difficult because of the low amplitude of the P wave and the corruption by noise. Also, the time frequency domain analysis of RR variability has disadvantage to get the details of irregular RR interval rhythm. In this study, we describe an atrial fibrillation detection algorithm through non-linear analysis of irregular RR interval rhythm based on the variability, randomness and complexity. We employ a new statistical techniques root mean squares of successive differences(RMSSD), turning points ratio(TPR) and sample entropy(SpEn). The detection algorithm was tested using the optimal threshold on two databases, namely the MIT-BIH Atrial Fibrillation Database and the Arrhythmia Database. We have achieved a high sensitivity(Se:94.5%), specificity(Sp:96.2%) and Se(89.8%), Sp(89.62%) respectively.

• Proceedings of the KIEE Conference
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• 2008.04a
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• pp.127-128
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• 2008

현대인의 생활 습관 및 고령화 사회의 도래에 따라 심장질환자의 수는 기하급수적으로 늘어가고 있으며 특히 정맥 환자는 그 중에서 가장 큰 분포를 차지하고 있다. 따라서 심장질환의 검출 및 치료를 위한 기기의 개발 및 발전이 시급하다고 볼 수 있다. 그 중 본 고에서는 인체 이식형/삽입형 Pacemaker인 ICD(Implantable Cardioverter Defibrillator)의 알고리즘을 소개하고자 한다. 본 고의 전체적인 구조는 ICD 기술의 필요성을 제시하고 본론에서는 부정맥(Arrhythmia) 소개 및 구현 대상, ICD 알고리즘 관련 국내외 현황, 빈맥의 검출 및 치료, 서맥의 검출 및 치료, 시뮬레이터 구현의 내용을 담았다 또한 알고리즘의 모듈 단위 구성도와 시뮬레이터(Simulator) UI(User Interface)를 제시하였다.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.3
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• pp.41-48
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• 2002

The bandwidth limitation of traveling-wave electroabsorption modulator(TW-EAM) is determined by the transit time, the velocity-mismatch between optical-wave and microwave, the impedance-matching, the dispersion and the microwave loss. In this paper, we introduce an hovel impulse response of TW-EAM considering transit time as well as velocity-mismatch. We analyze the effect of transit-time and velocity-mismatch at the same time, using the FDTD method. We investigate the modulation bandwidth by changing the depth of the intrinsic region. We suggest that the optimum depth of the intrinsic region is 0.2${\mu}{\textrm}{m}$ when the absorption coefficient($\alpha$) is 0.2${\mu}{\textrm}{m}$-1.

• Korean Journal of Food Science and Technology
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• v.48 no.5
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• pp.405-412
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• 2016

Illegally adulterated compounds, such as impotency drugs and their synthetic analogues, which have been purported to enhance sexual potency or mood, have been constantly detected in foods including dietary supplements. The adulterated foods with these illegal compounds may threaten public health because their safety and efficacy have not been verified. This study was aimed at investigating illegal compounds in foods and counterfeit products. 54 illegal compounds were assayed using a simultaneous analytical method involving liquid chromatography equipped with photo diode array (LC-PDA) and LC coupled with tandem mass spectrometry (LC-MS/MS). The method was validated in terms of selectivity, linearity, limit of detection (LOD), limit of quantification (LOQ), precision and accuracy. In 48 of 161 samples, we identified 7 different illegal compounds, including sildenafil, tadalafil, chlropretadalafil, demethylsildenafil, dimethyl-thiosildenafil, icariin and yohimbine. When purchasing products marketed for erectile dysfunction or aphrodisiacs, ulmost care should be taken owing to the possible presence of these illegal compounds.

• Korean Journal of Food Science and Technology
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• v.48 no.5
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• pp.424-429
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• 2016

Globally, obesity has been recognized as a serious health problem. Recently, slimming foods for weight loss and maintenance were found to contain anti-obesity drugs, their analogues, and prohibited ingredients. To avoid inspections by the Government, structurally modified analogs have been continuously synthesized. For rapid determination of adulterated slimming products, we simultaneously analyzed 21 illegal compounds using liquid chromatography (LC) equipped with photo diode array, and LC coupled with tandem mass spectrometry. The validation of the method was performed with regard to selectivity, linearity, limit of detection, limit of quantification, precision, and accuracy. We purchased 128 samples from the Korean market and online sources in the year 2015. In 31 samples, 3 illegal compounds were detected as follows: 9.9-135.3 mg/g of sibutramine, 0.2-17.5 mg/g of yohimbine, and 1.8 mg/g of icariin. This simultaneous detection method might prove to be a simple and rapid analysis for monitoring illegal compounds in slimming foods.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.8C
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• pp.1125-1132
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• 2004

In this Paper, we Propose an effective boundary matching based error detection algorithm using causal neighbor blocks to improve video quality degraded from channel error in block-coded video. The proposed algorithm first calculates boundary mismatch powers between a current block and each of its causal neighbor blocks. It then decides that a current block should be normal if all the mismatch powers are less than an adaptive threshold, which is adaptively determined using the statistics of the two adjacent blocks. In some experiments under the environment of 16bi1s burst error at bit error rates (BERs) of 10$^{-3}$ -10$^{-4}$ , it is shown that the proposed algorithm yields the improvements of maximum 20% in error detection rate and of maximum 3.5㏈ in PSNR of concealed kames, compared with Zeng's error detection algorithm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.10
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• pp.2223-2230
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• 2011

ECG is used to diagnose heart diseases such as myocardial ischemia, arrhythmia and myocardial infarction. Particularly, myocardial ischemia causes the shape change of the ST segment, this change is transient and may occur without symptoms. So it is important to detect the transient change of ST segment through long term monitoring. ST segment classification algorithm for making diagnosis myocardial ischemia is presented in this paper. The first step in the ST segment shape classification process is to detect R wave point and feature points based adaptive threshold and window. And then, the suggested algorithm detects the ST level change, To classify the ST segment shape, the suggested algorithm uses the slope values of the four points between the S and T wave. The ECG data in the European ST-T database were used to verify the performance of the developed algorithm. The best correct rate was 99.40% and the worst correct rate was 68.48%.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.9
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• pp.2021-2030
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• 2012

Premature ventricular contraction(PVC) is the most common disease among arrhythmia and it may cause serious situations such as ventricular fibrillation and ventricular tachycardia. Particularly, in the healthcare system that must continuously monitor patient's situation, it is necessary to process ECG (Electrocardiography) signal in realtime. In other words, the design of algorithm that exactly detects R wave using minimal computation and classifies PVC by analyzing the persons's physical condition and/or environment is needed. Thus, the patient adaptive pattern matching algorithm for the classification of PVC is presented in this paper. For this purpose, we detected R wave through the preprocessing method, adaptive threshold and window. Also, we applied pattern matching method to classify each patient's normal cardiac behavior through the Hash function. The performance of R wave detection and abnormal beat classification is evaluated by using MIT-BIH arrhythmia database. The achieved scores indicate the average of 99.33% in R wave detection and the rate of 0.32% in abnormal beat classification error.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.453-456
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• 2005

일반적으로 심전도는 심장계통의 질환을 판단할 때 사용된다. 이러한 심장질환의 이상 유무를 자동으로 진단하기 위해서는 QRS파형 검출을 필요로 하며, 이를 위하여 웨이블렛변환 방법이나 템플릿매칭, 룰 베이스 방법 등 여러 가지 방법들이 쓰이고 있으나, 심전도 신호가 표준화된 형태를 갖지 않는 경우는 검출 능력에 많은 한계를 갖고 있다. 본 논문은 파형의 베이스라인(baseline)을 기준으로 진폭 값에 절대치을 취하는 방법으로 파형의 R피크값을 검출하는 알고리즘을 제안한다. 결과를 검증하기 위해 MIT-BIH 데이타베이스에서 제공하는 데이터와 R피크값을 본 논문의 알고리즘으로 추출된 R피크값과 비교한 결과 96.7%의 검출률을 보였다.