• International Journal of Highway Engineering
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• v.10 no.2
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• pp.101-113
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• 2008

VMS are installed in many Korean highways in oder to give drivers informations such as travel time to destination, congestion and Incident situation. However, some guidelines for install VMS are restricted in only geometric factors although human factors considering driver behavior are very important to affect the VMS installation. Therefore, this paper are focusing on developing and verifying the discriminant model for VMS installation considering human factors. As a result, following outputs are obtained ; (1) developing the discriminant model using human factors of driving simulation experiments in oder to predict driver reading VMS messages safely detour highway. (2) proving that driving experiences in highway, personal driving history, vehicle speed orderly affects VMS installation (3) verifying predictability of developed model by comparing the real values with predicted values. (4) suggesting that VMS should be installed off 3.2Km from the I.C. of rural highway.

• Journal of Chest Surgery
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• v.42 no.1
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• pp.104-106
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• 2009

Extra-anatomic graft bypass is frequently performed instead of standard infrarenal aorto-iliac reconstruction in patients with Leriche syndrome in whom the thrombus extends to the level of the renal arteries. However, many different surgical options are still being attempted due to the unsatisfying long-term graft patency. We performed a descending thoracic aorto-bifemoral bypass graft with 14 and 14-7-7 mm artificial vessels through a posterolateral thoracotomy, a median laparotomy, and a longitudinal inguinal incision in a 48-year-old male who suffered from claudication with Leriche syndrome. After surgery, the patient recovered well and was discharged. The patient walked well without any symptoms during the 6 month follow-up period in the outpatient department. We have concluded that descending thoracic aorto-bifemoral bypass grafting could be considered as an alternative method for patients with Leriche syndrome in whom standard infrarenal aorto-iliac reconstruction is unsuitable.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.11
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• pp.35-45
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• 1999

This paper presents an interconnection network for load balancing on a multimedia server and proposes a simple probabilistic model of the interconnection network for analysing the traffic characteristics. Because the switch uses deflection algorithm for routing, the traffic load on the switch seriously affects deflection probability. In this paper, we trace the deflection probability as a function of the traffic load according to the model. By comparing the result with the empirical result, we prove that the model is useful for estimating the deflection probability and traffic saturation point against the amount of packets getting into the switch.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11b
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• pp.1123-1126
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• 2002

연구와 군사 목적으로 발전한 인터넷은 현재 많은 기업들과 일반인들이 사용하는 현대 사회의 중요한 기반 시설로 자리잡게 되었으며, 아울러 인터넷이 사회에 끼치는 영향이 커짐에 따라 여러 가지 목적으로 자신의 접속 위치를 우회하여 숨기고 인터넷 보안 모델의 취약점을 공격하는 침입자가 증가하고 있다. 따라서, 침입에 사용되는 기술과 그에 대한 대응 기법 또한 보다 복잡하고 정교해 지고 있으나 근본적으로 악의적 침입을 근절하는 능동적인 대응은 미약한 현실이다. 본 논문에서는 인터넷 환경에서 여러 가지 우회 경로를 통해 접근한 침입자의 실제 접속 위치를 효율적으로 추적하기 위해 기존 역추적 연구의 유형과 문제점을 살펴보고 차세대 인터넷 환경에서 활용 가능한 역추적 기법의 모델을 제시한다. 따라서, 기존 역추적 기법의 현실적으로 적용이 어려운 구성과 침입자의 보안 설정에 따른 추적 제한 등의 문제점을 살펴보고 그 해결 방안이 되는 새로운 역추적 시스템의 모델을 제시한다. 그리고, 본 연구에서 제시하는 모델은 기존의 연결 경로를 거슬러 추적하는 기법과 달리 프록시 등 우회 경로를 통해 접근한 침입자에 대해 직접 연결되는 프로토콜을 자동 실행 되도록 구성하여 접근한 침입자의 위치를 파악하는 모델이나. 이 모델을 적용할 경우 실제 적용 가능한 구성과 효율적인 추적 특성을 가지게 되며 구성 비용의 손실 또한 줄일 수 있게 되는 장점을 가지게 된다.

• Journal of Chest Surgery
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• v.40 no.9
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• pp.633-636
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• 2007

Coronary artery spasm immediately after the coronary artery bypass graft (CABG) surgery is rare but it can cause sudden and severe hypotension or a ventricular arrhythmia. We report a case of low cardiac output syndrome caused by a right coronary artery spasm following CABG that did not show any significant stenotic lesions on preoperative coronary angiography.

• Journal of Gastric Cancer
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• v.9 no.1
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• pp.1-5
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• 2009

In the past, conservative bypass surgery was usually performed for palliation of malignant obstruction of the gastrointestinal tract. However, endoscopic stenting was developed recently, and technical advances and clinical experience have made it possible to establish stent implantation as one of the main treatment options. There are several advantages in stent implantation over bypass surgery, such as high feasibility and technical success rate, non-invasiveness, rapid symptomatic response, short hospitalization, and cost-effect benefits. Complications, such as stent ingrowth, stent injury by bile or acid, and migration, may occur and early re-insertion is frequently needed. Recently, diverse novel stents which are powered to predict stent migration or ingrowth have been developed and are being used in the clinical setting. In general, stent implantation is known to be beneficial in patients who are expected to survive <6 months, and surgical bypass may be more effective in patients who can survive >6 months. In this review, we have compared the technical feasibility, clinical outcomes, complications, and cost-benefit between stent implantation and bypass surgery, and determined the optimal treatment strategy in malignant upper gastrointestinal obstruction.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.10a
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• pp.352-357
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• 1995

원자력발전소 화학 및 체적제어계통의 일부인 밀봉수주입계통은 원자로 냉각재펌프 밀봉장치로 일정한 온도 범위의 밀봉수를 공급하여 밀봉장치의 건전성 및 원자로 냉각재 계통의 압력경계를 유지한다. 그러나 발전소 과도상태시 밀봉수 주입온도가 허용범위를 벗어나게 되면 온도조절기 폐쇄신호에 의해 밀봉장치로의 밀봉수 주입이 차단될 수 있다. 본 연구에서는 발전소 과도시에도 밀봉수 주입이 지속적으로 가능한 설계개선 방안으로 밀봉수주입 열교환기 주위에 우회라인을 설치하는 방안을 제시하고 밀봉수주입 열교환기 내에서의 비정상 열전달 현상을 수치해석을 이용하여 분석하였다. 계산은 속도장을 정상 상태인 power-law분포로 가정하고 시간 t=0에서 입구온도가 급격히 변하는 과도시 우회 유량 및 시간 변화에 대한 온도분포, 국부 Nusselt 수, 평균온도 등을 구하였다.

• Journal of Chest Surgery
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• v.42 no.4
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• pp.532-536
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• 2009

Bypass surgery is performed for insuring continuity of a blood supply that is restricted due to obstruction of the native blood supply. Two types of surgery are commonly carried out: one is anatomic bypass and the other is extraanatomic bypass. Especially, extraanatomic bypass surgery is performed in patients who are a high risk for performing anatomical bypass surgery. The risk factors for anatomical bypass surgery are old age, infection, previous surgery and trauma. A 96-year-old patient underwent extraanatomic bypass surgery from the right femoral artery to the left femoral artery due to total occlusion of the left iliac artery, and 7 years after that operation, a pseudoaneurysm abruptly and spontaneously appeared from the bypass suture site without any predisposing factor. The lesion was revealed to be an organizing thrombus.

• Journal of Chest Surgery
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• v.42 no.4
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• pp.456-463
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• 2009

Background: Although the reports on re-operative coronary revascularization (redo-CABG) have increased, there are only limited reports on redo-CABG using arterial grafts. The aim of this study was to analyze the safety and feasibility of using various arterial grafts for redo-CABG. Material and Method: A consecutive series of patients who underwent 33 redo-CABGs from March 2001 to July 2008 were retrospectively reviewed. We performed conventional CABG in 17 patients, on-pump beating CABG in 7, off-pump CABG in 7 and minimally invasive direct coronary artery bypass in 2. The grafted that were used included 34 internal thoracic arteries (ITA), 14 radial arteries, 14 right gastroepiploic arteries and others. Arterial composite grafts were constructed in 26 patients. Of these, a previously patent in-situ left ITA was re-used as the in-flow of a composite graft in 10 patients. Result: No hospital deaths or major wound problems occurred. The post-operative complications included 2 myocardial infarctions (6%), 1 intra-aortic balloon pump insertion (3%), 5 cases of atrial fibrillation (15.1 %) and 3 neurologic complications (9.1%). The meanfollow-up duration was 31.1$\pm$22.7 months and the 3 year survival rate was 86.4%. There were 4 late deaths (2 cardiac deaths) and no recurrent angina during the follow-up period. Conclusion: Redo-CABG with using various arterial grafts is currently a safe, feasible procedure, but further investigation and long term follow-up are needed.

• Journal of Gastric Cancer
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• v.7 no.2
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• pp.82-87
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• 2007

Purpose: In gastric cancer patients with gastric outlet obstruction, there are several complications such as malnutrition and vomiting. Palliative enteral stenting is a less invasive procedure as compared with a gastrojejunostomy. The aim of this study was to determine whether there was a significant difference between patients that undergone palliative enteral slanting and patients that had received a bypass gastrojejunostomy. Materials and Methods: One hundred patients underwent palliative entering stenting and 3f patients were subjected to a surgical bypass gastrojejunostomy. We reviewed the medical records of the patients with gastric outlet obstruction secondary to far advanced gastric cancer that were diagnosed using a gastrofibroscope, UGI and abdominal CT, and were admitted to our institution between January 2000 and August 2006. The outcome of stent placement for gastric outlet obstruction was compared with palliative gastrojejunostomy during the same period. We excluded patients with recurrent gastric cancer and double cancer from this study. Results: There were significant differences between the group of patients that underwent slanting and the group of patients that received a gastrojejunostomy regarding the age of patients ($67{\pm}12$ vs. $57{\pm}9$, P<0.001) but not between the sex of the patients (M : F, 2 : 1 vs. 2 :1, P=0.637). The most common complication of stenting was tumor ingrowth (16/100, 16%) and the second most common complication was stent migration (14/100). Failure of the procedure occurred in only three patients. Twenty-three patients underwent re-slanting and one patient required open conversion with a gastrojejunostomy. The median time to the first meal was $4{\pm}2$ days in the stent group of patients and $6{\pm}2$ days in the gastrojejunostomy group of patients (P=0.001). The median postoperative hospital stays were 9 days in the stent group of patients and 15 days in the gastrojejunostomy group of patients (P=0.003). The mean survival periods were 11 months in the stent group of patients and 10 months in the gastrojejunostomy group of patients (P=0.937). Conclusion: There were no significant differences In the mean survival rates. An earlier first meal and a shorter hospitalization stay were found in the slanting group of patients compared to the bypass gastrojejunostomy group of patients. However, re-slanting was a concern due to tumor ingrowth and stent migration.