• Journal of Chest Surgery
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• v.34 no.1
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• pp.45-50
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• 2001

배경: 관상동맥우회술은 허혈성 심질환 환자에서 증상을 완화하고 급사를 방지할 수 있는 효과적인 치료방법으로 확립되었다. 그러나 80년대에 들어와 지금까지 사용되었던 대복재정맥편에 비해 동맥이식편의 장기개통율이 월등함이 알려지면서 좌내유동맥과 함께 사용할 수 있는 동맥이식편에 대한 관심이 증가하였다. 본원에서는 1998년부터 다동맥이식편을 이용하여 관상동맥 우회술을 시행하고 있으며, 조기성적에 대해 대복재정맥을 사용한 경우와 비교하고자 하였다. 대상 및 방법: 1998년 6월부터 1999년 5월까지 본원에서 관상동맥우회술을 시행받았던 355명의 환자중 심정지액을 이용하여 시행했던 153명을 대상으로 하였다. 76명의 단일 동맥편을 사용한 환자를 I군, 두 개 이상의 다동맥편을 사용한 77명의 환자를 II군으로 분류하여 수술전후 임상기록, 심초음파 및 관상동맥 조영술 소견등을 후향적으로 분석하였다. 결과: 술전 양군간에는 II군의 환자가 I군의 환자에 비해 더 젊고 흡연자가 많다는 것 이외에는 통계학적으로 차이는 없었다. 술후 조기사망은 각 군에서 1례씩 있었고 환자당 문합갯수에 통계학적으로 차이가 있는 것 이외에는 수술과정 및 술후 결과에서 차이는 없었다. 결론: 다동맥편을 이용한 관상동맥우회술을 시행한 결과 본원에서 학습기(learning period)임에도 불구하고 조기성적에 있어 대복재정맥을 이용한 경우와 차이가 없었다. 물론 중기 및 장기성적에 대한 지속적인 추적관찰이 필요하겠으나 이러한 조기성적은 동맥이식편을 이용한 관상동맥우회술이 환자의 장기생존에 도움을 줄 수 있으리라 사료된다. 또한 이러한 결과를 토대로 완전 동맥이식편 관상동맥우회술로의 전환이 이루어질 수 있으리라 생각된다.

• Journal of Chest Surgery
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• v.41 no.2
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• pp.202-209
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• 2008

Background: The introduction of Drug Eluting Stents (DES) decreased the number of patients referred for coronary artery bypass grafting (CABG). The impact of DES on CABG (Step 1) was studied and compared with the 1-year outcome after CABG with DES (Step 2). Material and Method: Surgical results for patients who underwent off-pump CABG (OPCAB) before the introduction of DES(n=298) were compared with those who underwent OPCAB after the introduction of DES (n=288) (Step 1). Postoperative 30-day and 1-year results were also compared between the patients who underwent percutaneous coronary intervention (PCI) using DES (n=220) and those who underwent OPCAB (n=255) (Step 2). Result: Since the introduction of DES, the ratio of CABG versus PCI decreased. In the CABG group, the number of high risk patients such as elderly patients (age 62 vs. 64, p=0.023), those with chronic renal failure (4% vs. 9%, p=0.021), calcification of the ascending aorta (9% vs. 15%, p=0.043), or frequency of urgent or emergent operations (12% vs. 22%, p=0.002) increased. However, there were no differences in the cardiac death and graft patency rates between the two groups (step 1). During the one-year follow up period, the rate of target vessel revascularization (12.3% vs. 2.4%, p<0.001) and major adverse cardiac events (MACE: death, myocardial infarct, TVR) were higher in the DES than the CABG group (13.6% vs 4.3%) (stage 2). Conclusion: Introduction of DES decreased the number of patients referred for surgery, and increased the comorbidity in patients who underwent CABG. DES increased the rate of target vessel revascularization, and the occurrence of MACE during the 1-year follow-up. However, there was no difference in the incidence of myocardial infarction and cardiac death between the two groups.

• Journal of Chest Surgery
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• v.32 no.5
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• pp.480-483
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• 1999

The widely accepted method for coronary artery bypass grafting(CABG) is performing the distal coronary artery anastomoses on the flaccid and nonbeating heart with the aid of cardiopulmonary bypass(CPB) and cardioplegic arrest. However, current cardioplegic techniques are not consistent in avoiding myocardial ischemic damages especially in high risk patients undergoing CABG. In this regard, "Off-Pump" seems to be an ideal method for preventing myocardial ischemic damage and adverse effects during CPB. However, "Off-pump" CABG is not always technically feasible. We report 2 cases of "On-pump" CABG performed on the beating heart in high risk patients; The first patient had left ventricular dysfunction(Ejection Fraction=25%), and the second patient had cardiogenic shock after percutaneous transluminal coronary angioplasty.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.3
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• pp.655-659
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• 2016

In this paper, we propose new detection and detour methods against packet drop attacks for availability in the Internet of Things (IoT) based on the IEEE 802.15.4e and RPL protocol standards that employ IPv6. We consider the rank value of RPL and the consecutive packet drops to improve the detection metrics, and also take into account the use of both sibling and child nodes on a RPL routing path to construct the detour method. Our simulation results show that the proposed detection method is faster than the previous result, and the detour method improves the detour success rate.

• The Transactions of the Korea Information Processing Society
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• v.5 no.12
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• pp.3109-3116
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• 1998

본 논문에서는 대규모 병렬컴퓨터의 구현에 적합한 위상구조인 교차메쉬구조에서, 균등한 메시지분포를 갖고 메시지의 경쟁이 있는 실제적 상황에서 상호접속망내의 메시지의 경로를 선정하기 위한 방법들을 제안하고, 이의 성능을 검증하기 위해 우회 경로설정 알고리즘을 이용하여 시뮬레이션을 하였다. 교차메쉬의 특성상 최적경로의 수가 다른 구조들에 비해 다양하다는 특징을 이용하여 최적경로의 수를 우선순위에 반영한 우회조건 및 대각방향의 링크를 효율적으로 활용하기 위한 링크선정방법에 따를 교차메쉬의 최대지연(maximum delay), 평균지연(average delay) 및 메시지처리율(throughput)을 구하고 이를 비교 고찰하였다. 메시지 전송시 최적인 경로상의 링크에 경합이 생길 경우 최적 경로의 수가 적은 메시지가 높은 우선순위를 가지며 만약 같은 조건이라면 우회한 횟수가 많은 메시지가 높은 우선순위를 갖는 우회조건 LD를 사용하며 이 우선순위에 따라 경로를 선정할 차례가 된 메시지가 선택할 수 있는 최적경로의 수가 많을 경우 대각방향의 링크로 우선적으로 전송할 경우, 오래된 메시지가 높은 우선순위를 갖는 우회조건 A에 의한 방법에 비해 최대지연, 평균지연 및 메시지처리율에 있어서 각각 이상값에 대한 개선목표치의 약58%, 70% 및 31%의 성능개선이 있었다.

• Journal of Chest Surgery
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• v.38 no.11 s.256
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• pp.733-738
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• 2005

Background: The possibility of incomplete revascularization and development of flow competition after revascularization of the borderline lesion made the hybrid strategy as an option for complete revascularization. Material and Method: From January f998 to July 2004, 25 $(3.2\%)$ patients underwent hybrid revascularization among 782 total OPCAB procedures. Clinical results and angiographic patencies were evalulated. Percutaneous coronary intervention (PCI) was peformed before CABG in 8 patients and after CABG in 47 patients. Result: The causes of PCIs before CABG were to achieve complete revascularization with minimally invasive surgery (n=7) and emergent PCI for culprit lesion (n=1). The indications of PCIs after CABG were high possibility of flow competition in the borderline lesion of right coronary artery territory (n=8), diffuse atheromatous lesion preventing anastomosis of graft (n=5), severe calcified ascending aorta with no more arterial grafi available (n=3), and intramyocardial coronary lesion (n=1). Mean number of distal anastomoses was $2.3\pm1.0$. Mean number of lesions treated by PCI was $1.2\pm0.4$. There was no operative or procedure-related mortality. PCI-related complication was periprocedural myocardial infarction in one patient, and complications related to CABG were transient atrial fibrillation (n=5), perioperative myocardial infarction (n=1), and transient renal dysfunction (n=1). Early postoperative coronary angiography $(1.8{pm}1.6days)$ revealed $100\%$ patency rate of grafts (57/57). The stenosis occurred in one patient performed PCI before CABG, which was successfully treated with re-ballooning. During midterm follow-up (mean; $25{\pm}26$ months), 1 patient died of congestive heart failure. All survivors (n=24) accomplished follow-up coronary angiographics, which showed .all grafts (56/57) were patent except one string sign. In-stent restenosis was developed in 2 patients who received bare metal stents. Conclusion: In selected patients, complete revascularization was achieved with low risk by taking the hybrid strategy.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.10a
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• pp.345-350
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• 1997

1980년대 이후로 원자로냉각재 온도를 계측하기 위한 RTD우회배관 계통을 제거하고 RCS 배관에 직접삽입식 RTD를 설치하여 온도를 계측하고 있다. 이에 고리 1,2,3,4호기에서도 직접삽입식 RTD를 설치하고자 한다. 이때 고온관 온도층화에 의한 계통측정정확도(PMA)가 설비 개선후 어떻게 변하는지 평가하였다. 평가 결과 RTD우회배관 계통의 PMA는 1.3℉F이고 직접삽입식 RTD 계통은 1.0℉로 계산되어 설비 개선후의 불확실도가 작아짐을 확인하였다.

• Journal of Chest Surgery
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• v.30 no.3
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• pp.326-329
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• 1997

Coronary artery bypass grafting(CABG) without cardiopulmonary bypass(CPB) is now an accepted technique of myocardial revascularization in selective cases of coronary arterial occlusive disease. The lesion was total(100%) occlusion of proximal right coronary artery(RCA) without any evidence of dis,Base in the rest of coronary arteries. Percutaneous transluminal angioplasty(PTCA) was tried but unsuccessful. We herein report a case of successful CABG to right coronary artery without CPB on a patient with complete occlusion of RCA and symptomatic wit minimal activity.

• Journal of Chest Surgery
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• v.37 no.10
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• pp.865-867
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• 2004

Development of intraoperative aortic dissection during coronary artery bypass surgery is extremely rare with catastrophic outcomes resulting in high rates of morbidity and mortality. The prognosis is highly dependant upon prompt diagnosis and emergent treatment. We report our experience on a 72 year old female patient who successfully received ascending aortic graft replacement for acute intraoperative aortic dissection during coronary artery bypass procedure.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.12B
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• pp.1051-1059
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• 2003

The key feature of GMPLS is the provision of network resources and the automatic set-up of a path. And the mechanism of protection and restoration of a path is presented when network component fails. This paper suggests CR-LDP Static Detour Mechanism and Dynamic Detour Mechanism. CR-LDP Detours are a mechanism to set up detour paths automatically at every node to protect working path. Hence suggested mechanism performance is compared with existing mechanisms by computer simulation.