• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.4
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• pp.181-188
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• 2006

The purpose of this study is to predict the defibrillation success of a ventricular Fibrillation ECG signal using time-frequency analysis. During CPR, coronary perfusion pressure and electrocardiogram were measured. Parameters extracted from time-frequency domain were served as predictor of resuscitation success. Time frequency distribution(TFD) of ECG signals was estimated from the smoothed pseudo Wigner-Ville distribution(SPWVD). Median frequency, peak frequency, 1/f slope, frequency band ratios$(2{\sim}4Hz,\;4{\sim}6Hz,\;6{\sim}8Hz,\;8{\sim}10Hz,\;10{\sim}12Hz,\;12{\sim}15Hz)$ were extracted from each TFD as function of time. Paired t-test was used to determine the differences in ROSC and non-ROSC groups. In the statistical results, we selected four significant parameters - median frequency, 1/f slope, $2{\sim}4Hz$ band ratio, $8{\sim}10Hz$ band ratio. We made an attempt to predict defibrillation success by combining features extracted from time frequency distribution. Independent t-test was used to determine the differences ROSC and non-ROSC groups. Consequently, we selected four significant parameters-median frequency, 1/f slope, $2{\sim}4Hz$ band ratio, $8{\sim}10Hz$ band ratio. The relationship between coronary perfusion pressure and ECG parameters was analyzed with linear regression analysis. R-square value was 55%. 1/f slope and $8{\sim}10Hz$ band ratio had the significant relationship with coronary perfusion pressure.

• Journal of Chest Surgery
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• v.34 no.4
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• pp.361-364
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• 2001

자가 폐동맥 판막을 이용한 대동맥 판막 치환술을 항응고제 복용이 필요없고 내구성이 어느정도 입증되어 늘어나고 있으나, 자가 폐동맥 판막을 이용한 승모판막 치환술은 국내에 보고된 예가 없다. 53세 여자 환자로 류마티스성 승모판막 협차가 및 폐쇄부전, 삼첨판막 폐쇄부전, 만성 심방 세동, 그리고 자회전 관상동맥의 폐색등으로 진단받은 환자에서 자가 폐동맥 판막을 이용한 승모판막 치환술 및 maze 술식, 삼천판막 성형술, 관상동맥 우회수술을 시해하였다. 수술후 특별한 문제없이 회복하였으며 술후 시행한 심초음파 검사상 자가 폐동맥 판막의 이상 소견없이 잘 기능하고 있으며 항응고제 복용없이 잘 지내고 있다.

• Journal of Yeungnam Medical Science
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• v.17 no.1
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• pp.75-81
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• 2000

Background: Systemic embolism, especially, cerebral infarction is one of the most important complications in patients with mitral stenosis. The authors analyzed the some factors that could predict the development of cerebral infarction in cases of mitral stenosis and propose preventive therapeutic measures. Methods: Retrospective study of 127 patients with rheumatic mitral stenosis was performed by analyzing their medical records for transthoracic(TTE) or transesophageal echocardiography(TEE) over a 12 months period. The patients were divided into two groups according to the presence (Group I: n=26, age: $55.0{\pm}13$ years) or absence (Group II: n=101, age: $48.5{\pm}13$ years) of cerebral infarction. No significant difference was observed between the two groups with respect to sex and functional class. Results: Patients in group I were older ($55.0{\pm}13$ vs $48.5{\pm}13$;p<0.05). had more dilated left atrial size($5.10{\pm}0.48$ vs $4.81{\pm}0.70$;p<0.05) and smaller mitral surface area($1.01{\pm}0.39$ vs $1.21{\pm}0.45$;p<0.05). In Group 1. the incidence of atrial fibrillation(22 out of 26 vs 57 out of 101;p<0.05) and spontaneous left intra-atrial contrast phenomenon(22 out of 26 vs 44 out of 101;p<0.05) was more frequently observed. On multivariate analysis. atrial fibrillation and anticoagulant therapy were the independent predictive factors. Conclusion: Age, left atrial dilatation, the severity of mitral stenosis, the presence of spontaneous contrast, and especially the presence of atrial fibrillation are the main predictive factors of the development of cerebral infarction in mitral stenosis. Patients presenting one or several of these factors may benefit from prophylactic anticoagulant treatment.

• The Korean Journal of Emergency Medical Services
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• v.16 no.1
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• pp.81-90
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• 2012

Objectives: This study is to research delay time comparison for later defibrillation after hands off according to the changes in defibrillation electrodes. Study purpose: In defibrillation treatment that is the only way for cardiac arrest by arrhythmia, it is to find defibrillator device which can minimize late defibrillation delay time after important affect of hands off. Study object and method: After hands off according to the defibrillator device, we collected total 40 people for emergency medicine doctor, internal medicine doctor, general surgeon, nurse, emergency medical technician who are working at 2 CN, CS University hospitals in Gwangju Jeollanamdo district to find out hand off shock interval(HOSI). We then researched their general properties like occupation sector, experiences in clinic, gender, completion of AHA ACLS-P training and more. Then 40 participants continued ventricular fibrillation cardiac arrest simulation training (using human-model mannequin) designed by researcher and performed their roles as defibrillation operator. Each of participant used manual paddle and performed 4 times of defibrillation (150J) during 8 minutes of CPR and in 8day, the defibrillator devices were replaced from manual paddle to self-adhesive electrodes pads and 4 times of defibrillation (150J) under same simulation condition as manual paddle were performed. Study result: In comparison for delay time of later defibrillation after hands off of manual paddle and self adhesive electrodes pad, the self adhesive electrodes pad ($7.0{\pm}0.5sec$) seemed to reduce delay time of later defibrillation significantly (p<0.05) compared to manual paddle ($10.0{\pm}0.9sec$). The self adhesive electrodes pad, according to the general properties of participants, had no particular change in delay time after later defibrillation for the statistics (p>0.05) but the manual paddle had statistically significant differences for the occupation sector, experiences in clinic and gender (p<0.05). Conclusion: In defibrillation, the self adhesive electrodes pad($7.0{\pm}0.5sec$) showed short HOSI compared to manual paddle ($10.0{\pm}0.9sec$) significantly (p<0.05) and it applied identically for both existence and non-existence of ACLS-P training completion, experiences in clinic, gender and occupation sector. The manual paddle had also significant difference in experiences in clinic and occupation sector (p<0.05). which means the effect on HOSI according to the job mastery. Therefore, if the clinic experience is short or in case for the occupations without frequent defibrillation treatment has a danger of lowering success rate for the defibrillation using manual paddle. Therefore, it is true that using self adhesive electrodes pad for defibrillation electrodes when performing manual defibrillation in pre-hospital as well as in-hospital steps can generally minimize delay time of later defibrillation after hands off.

• Fire Science and Engineering
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• v.27 no.6
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• pp.122-128
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• 2013

This study analyzed the emergency activity daily reports and emergency instruction sheets of the research subjects and proceeded with the shockable cardiac arrest cases transported to 119 emergency units for two years before the hospital from January 1, 2010 through December 31, 2011. The most frequently predicted instruction by the dispatchers at the 119 Emergency Situation Control Center was 74 cases of fainting (33.3%). Among varied types of predicted instructions, 112 cases (50.5%) like fainting, chest pain, general prostration and others were not able to be predicted while predictable instructions involved with cardiac arrest such as consciousness disorders, difficult breathing, cardiac attacks and convulsion were 110 cases (49.5%). In such cases, success rates of cardiopulmonary resuscitation (CPR) trials by eyewitnesses at predictable instructions involved with cardiac arrests were significantly higher. As mentioned, situation agents must categorize types of cardiac arrests accurately by posing questions over assessments regarding patients' consciousness and respiration in detail. The patients categorized by such methods must guide eyewitnesses to be able to do CPR. Moreover, not only emergency medical technicians who receive predictable instructions involved with cardiac arrests given by dispatchers (49.5%) but also filed emergency medical technicians who are not able to reach a precise conclusion to non-cardiac arrests on unpredictable instructions on cardiac arrests (50.5%) must prepare for situations related to cardiac arrests before being dispatched to the field.

• The Korean Journal of Emergency Medical Services
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• v.15 no.1
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• pp.79-88
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• 2011

Purpose : Prehospital emergency care for shockable rhythm is one of major concerns of emergency medical services. But, in Korea, prehospital medical service systems are not yet well established. We tried to offer one of the fundamental data to develop of these system. Method : After application of exclusion criteria, 200 patients who had shockable rhythm from January to December, 2008 were included in this study. Restrospective review of Prehospital care Reports of these patients was done. Result : Total 200 cases of shockable rhythm and prehospital arrest were analyzed. The rates of assessment of vital signs were 89.0%, the rate of level of consiousness was 99.5%. Just 6.0% were communicated with medical director providing the prehospital care. The frequency of defibrillation was performed 58.5%. Conclusion : Survival rate was higher in defibrillation group than that of nondefibrillation group(20.5% vs 2.4%, p=0.000).

• The Korean Journal of Emergency Medical Services
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• v.16 no.3
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• pp.9-18
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• 2012

Purpose : The purpose of this study was to determine the changes that occur due to the real-time monitoring of paddle pressures which has an important influence on the defibrillation success rate in defibrillation treatment known as the only treatment for cardiac arrest patients with VF. Methods : 40 people participated in the cardiac arrest simulation training and played the role of the defibrillation operator. Investigators measured the pressure of paddle while defibrillating by using instrument which was developed by the investigator. Results : Through real-time monitoring of the paddle pressures of defibrillator by indicator, the front sternum paddle showed a 77.5% success rate and the apex paddle showed a 40% success rate. While the values without monitoring the paddle pressures, the front sternum paddle showed a 51% success rate and the apex paddle showed a 20% success rate. These experiment revealed statistically significant(p <.001) low success rate. Conclusion : The method of monitoring the paddle pressures during defibrillation showed that the paddle can be precisely gripped. The success rate of paddle pressures is significantly correlated with height, weight and grip strength.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.59-60
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• 2008

비선형 부하의 급증으로 고조파로 인한 문제가 점차적으로 커지고 있으나 국내에서는 고조파 관리 기준 및 적용절차의 미비로 제대로 된 고조파 관리가 이루어지지 못하고 있다. 따라서 국내 송전계통에 연계되어는 있는 고압수용가에서 계통으로 유출할 수 있는 고조파 크기를 산정하는 프로그램이 필요하다. 국외에서는 IEC 61000-3-6 고조파 관리기준을 바탕으로 고압 수용가의 고조파 허용치 산정 알고리즘이 개발된 상태이다. 그러나 이 알고리즘을 국내 송전계통에 바로 적용할 수 없다. 따라서 이 알고리즘을 바탕으로 국내 송전계통 실정에 맞는 알고리즘으로 보완하고, 마이크로 소프트 엑셀 프로그램을 이용하여 고압 수용가 고조파 허용치 산정 프로그램을 개발하였다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.12
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• pp.110-114
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• 2008

In recent years, the standard for harmonics has established and applied in many countries. However a harmonic management has not performed for the absence of standard and procedure in Korea. For this reason, the standard establishment for harmonic based on the main purpose of international harmonic standards and property of domestic transmission system is required. This paper describes the software of assessment of harmonic emission limit for customer at HV System using Microsoft Excel.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.3
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• pp.39-43
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• 2004

국제적인 환경 규제 문제($CO_2$, SF$_{6}$(육불화황), PFC (과불화화합물) 등)가 새로운 무역장벽으로 등장하여 우리나라 주요 산업 부문에 미치는 영향이 점차 현실로 나타나고 있다. 이러한 환경 규제에 적절한 대처를 하기 위해 에너지 소비 증가와 이에 따르는 에너지 소비 패턴 및 인식에 대한 새로운 접근 방법이 요구되고 있다. 그동안 전력기기의 고효율화, 에너지 효율 향상과 수요관리 강화, 미활용 에너지원의 이용률 제고, 집단에너지 보급 확대 등 하드웨어적인 기술개발에 중점을 두고 추진되었으나, 앞으로는 전원설비, 전력전송 설비, 부하설비 등의 최적 설계기술을 통한 에너지절약 기술개발과 같은 소프트웨어적인 기술 개발이 요청되고 있다. (중략)