• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.354-362
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• 2017

Due to population aging and westernized lifestyle, ischemic heart diseases are increasing, and Korea has one of the highest lengths of stay for ischemic heart diseases. Since the increase in the length of stay is a major cause of the increase in medical expenses, it is necessary to prepare a plan to manage the length of stay. Accordingly, this study was conducted to identify the factors influencing the length of stay of ischemic heart disease, and provide the elementary resources necessary for the management of the length of stay. The study subjects were 566 ischemic heart disease patients of a tertiary hospital. As the result of the study, first, the number of inpatients with chest pain as the chief complaint was the largest. Second, the average length of stay was 4.89 days, and the length of stay varied depending on the type of ischemic heart disease. Third, the age of over 75 years, diabetes, and dyspnea were the factors increasing the length of stay. Therefore, for management of adequate length of stay for ischemic heart disease, it is important to prevent the progression of illness through blood sugar control for ischemic heart disease patients with diabetes. Also, it is necessary to prepare a system where patients can visit hospitals as fast as possible if they have any symptoms.

• Journal of Chest Surgery
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• v.37 no.9
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• pp.762-767
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• 2004

With the developement of non-invasive surgical techeniques, coronary artery bypass graft without cardiopulmonary bypass has become popular. We compared the preoperative risk factors and in-hospital outcomes of patients having off-pump CABG with these having on-pump CABG. Material and Method： From January 2001 to June 2003, 87 patients underwent CABG. Thirty-sin patients underwent on-pump CABG, fifty-one patients under-went off-pump CABG. Preoperative risk factors, extent of coronary disease, operative time, postoperative endotracheal intubation time, duration of ICU stay & hospital stay, the amount of bleeding and postoperative levels of cardiac enzymes were compared in both groups, Result: The were no differences in their sex ratios, ages, preoperative risk factors, preoperative Ml, Canadian classes, extent of coronary artery diseases and, echocardio-graphic ejection fraction between Off-pump CABG and On-pump CABG groups. Off-pump CABG group had significantly lower mean operative time (270$\pm$79.3 min vs 372$\pm$142.2 min, p＜0.001), mean ventilation time (17.1$\pm$13.4 hr vs 24.3$\pm$17.8 hr) and CK-MB level (8,9$\pm$18.7 IU/L vs 25.7$\pm$8.4 IU/L) than on-pump CABG groups, On-pump CABG group had more distal grafts (2.2$\pm$0.5 vs 1.7$\pm$0.71 than Off-pump CABG groups did. There were no differences in their postoperative complications and outcomes including amount of postoperative bleeding for 24 hrs, reoperation for bleeding control, mean in-hospital days, postoperative infection, renal failure and neurologic complications between Off-pump CABG and On-pump CABG groups. Conclusion: This study showed that patients who underwent Off-pump CABG had less operation time & intubation time and lower CK-MB level; however, they also have less distal graft. Even though CABG without CPB provided satisfactory results, more clinical experience & longer follow-up is required.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.9
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• pp.146-155
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• 2018

This study was conducted to evaluate the clinical outcomes of coronary artery bypass surgery for ischemic heart disease according to use of a cardiopulmonary bypass machine. The subjects were 10,981 patients who underwent coronary artery bypass grafting for ischemic heart disease from July 2008 to June 2012. Analysis data were retrospectively collected using health insurance claims data. The results of the study showed that mean time to surgery (280 min vs 357 min, p<0.0001) and intubation time (about 24 hours vs 40 hours, p<0.0001) were significantly shorter in the Off-Pump CABG (OPCAB) group than in the On-Pump CABG (ONCAB) group. The rate of reoperation because of postoperative bleeding and hematoma was lower in the OPCAB group (2.7% vs 8.3%, p<.0001). The odds ratio of risk adjusted 30 days mortality rate was 0.339 (0.266-0.434) and the postoperative length of stay was decreased in the OPCAB (p<0.0001). Overall, the 30 days mortality and reoperation rates were lower in the OPCAB, as was the resources use.

• The Science & Technology
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• v.32 no.6 s.361
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• pp.82-83
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• 1999

미국의 수리과학은 세계 주도적 위치에 있기는 하지만 막대한 재원의 뒷받침이 없이는 그 위치를 유지하기 어려운 실정이다. 그동안은 공산권 등에서 이민온 수학자들이 세계적 권위를 유지해 왔지만 직장도 적고 봉급도 낮을 뿐만 아니라 박사학위를 받는데도 너무 시간이 많이 걸려 대학원생들이 외면하고 있기 때문에 미국의 수리과학은 갈수록 흔들리고 있는 실정이다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.1
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• pp.93-99
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• 2013

It is expected to continue to increase the number of people who enjoy marine and water sports due to the increase of leisure time because of income increase, the five-day workweek, etc. However, in the safety awareness, the development of equipment is just in the early stage. Established system for fundraising is required for Korean marine and water sports to be developed first. Should the fund be spent on the safety and development of domestic equipment for marine and water sports, it would make for a safer and more enjoyable sports for the people. The profit return measures of motor boat race, among marine and water sports, are surveyed and analyzed to suggest the measures stated above. Japanese legal structure and the profit return measures on motor boat race, which are about 60 years ahead than Korean systems, were analyzed and led to suggest the establishment of professional institutions which promote motor boat, etc. and the legal improvement for funding.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.537-538
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• 2015

전기혜택을 받지 못하는 개발도상국의 도서지역이나 산간지역 등에 전기를 공급하기 위한 방법으로 마이크로그리드를 구축하고 있다. 그러나 24시간 전기 공급을 위해서는 많은 투자 재원이 필요하다. 따라서 본 논문에서는 첨두 부하를 삭감하여 공급지장을 감수하더라도 투자 재원을 줄여 전기 공급의 확대를 목표로 한다. 또한 HOMER 프로그램을 이용하여 첨두 부하 삭감을 고려하는 가상발전기 개념을 도입하고 발전기의 고장정지율을 고려한 감도 분석을 통하여 마이크로그리드의 각 설비별 기대 적정 규모를 구하는 방법론을 제안한다.

• Proceedings of the Korea Contents Association Conference
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• 2013.05a
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• pp.445-446
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• 2013

전국에 1인 전문가 체제의 박물관이 늘어나고 있다. 그러나 1인의 전문가가 박물관의 다양한 구성요소들을 콘텐츠화하여 운영하기 위해서는 시간과 자원이 부족하다. 본 논문은 1인 전문가 체제의 박물관이 운영되고 활성화되는 모델을 '공유'에서 찾고자 한다. '공유'는 박물관이 위치한 지역공동체의 요구를 수용하고 인적, 물적 자원을 확장하여 활용하는 방법이다. 기존의 박물관 협력망 사업은 재원 지원이 가능한 대규모 박물관이 주최가 되어 1인 체제 박물관을 지원해주는 방식으로 진행되었다. 기존의 체제가 박물관 지식의 전문성을 강조한 경쟁 원리를 기반으로 한다면, 지역과 박물관의 공유 방식은 소통을 기반으로 융 복합의 패러다임을 제시한다. 재원과 인력을 지역사회에서 충당하는 1인 체제 박물관은 자생(自生)이 가능하다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2019.06a
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• pp.156-157
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• 2019

본 논문에서는 스파이크그램 기반의 주파수 및 시간 특성을 이용한 음속 인식 방법을 제안한다. 기존의 MFCC 특성은 프레임 단위의 평균 특성이기 때문에 시간 해상도가 낮고, 짧은 음소의 특성을 반영하기에는 어렴움이 있다. 반면, 스파이크그램은 청각 모델을 기반으로 샘플 단위로 계산하기 때문에높은 시간 해상도를 가진다. 고 해상도의 스파이크그램을 분석하면 음소 인식에 특화된 특성 벡터를 추출할 수 있다. 추출된 특성으로 심층 신경망을 학습시켜 음소 인식기를 구현하였고, TMIT 테이터 세트로 성능을 평가하였다. 성능 평가를 통하여 스파이크그램 기반의 새로운 시간-주파수 특성을 사용하여 MFCC 특성과 유사한 성능의 음소인식이 가능한 것을 확인하였다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2022.06a
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• pp.61-62
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• 2022

본 논문에서는 시간 영역 에너지의 companding을 이용하여 오디오 부호화에서 발생하는 프리 에코를 효과적으로 감소시키는 방법을 제안한다. 일반적으로 오디오 부호화는 블록 단위의 변환 부호화를 사용하므로 과도 구간에서 프리 에코를 발생시킨다. 프리 에코를 줄이기 위한 기존 TNS 방법은 주파수 영역에서 선형 예측 방법을 사용하며, 부가 정보 전송이 필요하고 성능이 낮은 문제점을 가진다. 제안하는 방법은 시간 영역 에너지의 동적 범위를 감소시킨 후 부호화 하고, 복호화 이후에 에너지를 복원하는 과정을 통하여 양자화 오차의 시간 영역 에너지 분포를 조정하여 프리 에코를 감소시킨다. 제안하는 방법이 TNS보다 우수한 프리 에코 감소 성능을 가지는 것을 확인하였다.

• Journal of Chest Surgery
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• v.35 no.11
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• pp.812-816
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• 2002

Pericardial effusions result from various conditions such as inflammation, malignancies, open heart surgery and uremia. Recently, video assisted thoracic surgery (VATS) has been used for diagnostic and therapeutic purposes in the management of pericardial effusion and intrathoracic lesions due to its ability to provide outstanding visibility of intrathoracic structures with less pain, superior cosmetic effects, and shorter hospital stay Material and Method: From April 1995 to October 2001, 51 patients received pericardial window operation via either thoracoscopic(Group A, n＝37, m:f＝18:19, mean age＝56.4 yrs)or thoracotomy approach(Group B, n＝14, m:f＝8:6, mean age=58.4 yrs). Result: In group A, the operation time, duration of chest tube insertion, recurrence rate of pericardial effusion, and postoperative hospital stay were 61.2 minutes, 9.3 days, 2.7%, 16.2 days, respectively while in group B these values were 58.4 minutes, 12.2 days, 7.1, and 17.3 days. The number of injections for pain control in group A were 4.2 times, whereas in group B it was 6.3 times. Although there was a tendency for the mean hospital stay and duration of chest tube insertion to be shorter in group A than in group B, these differences did not reach statistical significance. There was also no significant difference in the operation time and recurrence rate between the two groups. Conclusion: The safety and effectiveness of VATS in the management of pericardial effusion is comparable to the open thoracotomy method. It allows for a shorter hospital stay, duration of chest tube insertion, lesser postoperative pain and a smaller skin incision.