지주막하 출현 환자에서 Transcranial Doppler를 이용한 뇌동맥 혈류 속도 측정

심재홍 인제대학교 1998 仁濟醫學 Vol.19 No.2

1997년 1월 1일부터 1997년 6월 30일까지 6개월간 본원 신경외과에 입원하여 수술을 시행하였던 뇌동맥류파열 환자 72예 중 63예에서 중대뇌동맥의 평균 혈류속도를 경두개 도플러 초음파를 이용하여 측정하여, 임상적으로 뇌혈관 연축이 있었던 군 및 뇌전산화단층촬영상 Fisher 등급에 따른 뇌혈관연축정도를 비교 분석하였다. The velocity of blood flow through the middle cerebral arteries was measured by transcranial Doppler sonography in 63 patients with aneurysmal subarachnoid hemorrhage. The velocity became greater from 4th day after the hemorrhage reached a plateau on 6th-11th day and declined there after. The velocity through the arteries of the patients who showed Fisher grade III, IV on CT scan within 3 days after the hemorrhage was significantly greater than that of the patient who showed Fisher grade I, II. The maximum mean velocity in the patients with delayed ischemic deficits was greater than that in the patients without delayed ischemic deficits. Transcranial Doppler ultrasonography makes it possible to measure, noninvasive and repeatly the changes in blood flow velocity that occur with vasospasm.

Recent Advances in Therapeutic Biliary Endoscopy

심재홍 白中央醫療院 2004 仁濟醫學 Vol.25 No.1

Objectives: The goal of the aneurysm surgery is complete circulatory exclusion of the aneurysm without compromise of the normal vessels. Failure to obliterate intracranial aneurysm completely during initial surgery still occurs in spite of recent technical advances. Methods and Materials: Between 1980 and November, 18th 2002, we have performed 2,500 cases aneurysm surgery. Among these, we experienced 29 reoperated cases for the failed initial aneurysm surgery, including 7 intraoperative clip readjustment after intra-operative angiography. Results: Twenty-nine cases were reoperated for the failed surgery. Of them, 7 cases were performed intraoperative angiography and the others(22) were not. 3 cases were performed initial operation in other hospital. The number of location of aneurysm was 15 A-com, 7 ICA and 5 MCA. tec. The causes of operations were vessel occlusion(8), residual neck(7), rebleeding after coating(5), aneurismal filling(3), slipped clip(2) and others. Clinical outcomes were better than in readjustment group after intraoperative angiography; above favorable outcome in 6(85.7%), but 16(72.7%) in group without intraoperative angiography. Conclusion: Reoperative management for failed aneurysm surgery is very difficult because of scar tissue, coating material and previously placed clip etc. Preoperative and postoperative detailed radiological and clinical assessment should be performed to determine the success of surgical treatment. During operative procedure, the use of intraoperative angiography, endoscopy and doppler sonography etc. will reduce the need of another operation and decrease the risk of post operative complications.

Virus Throttling의 웜 탐지오판 감소 및 탐지시간 단축

심재홍,김장복,최경희,정기현,Shim Jae-Hong,Kim Jang-bok,Choi Hyung-Hee,Jung Gi-Hyun 한국정보처리학회 2005 정보처리학회논문지 C : 정보통신,정보보안 Vol.12 No.6

인터넷 웜(worm)의 전파속도는 매우 빠르기 때문에, 발생초기에 웜의 전파를 탐지하여 막지 못하면 큰 피해를 초래 할 수 있다. 새로운 세션에 대한 연결요청을 일정 비율이하로 제한함으로써 웜의 발생여부를 탐지하는 바이러스 쓰로틀링(virus throttling)[6, 7]은 대표적인 웜 조기탐지 기술 중의 하나이다. 대부분의 기존 기술은 지연 큐 관리에 있어서 동일한 수신 IP 주소들을 개별적으로 처리함으로써 웜 탐지의 오판 가능성을 증가시켰고, 지연 큐가 가득 찼을 때에만 웜이 발생했다고 판단하는 단순 판단 기법을 사용했다. 본 논문은 지연 큐에서 동일 수신 IP 주소들을 하나의 연결 리스트로 묶어 별도로 관리함으로써 동일 수신 IP들을 중복하여 지연 큐에 저장하지 않는 이차원 지연 규 관리방안을 제안한다. 개선된 바이러스 쓰로틀링은 지연 큐 길이 산정 시동일 수신 IP 주소들을 중복하여 계산하지 않기 때문에 웜 탐지 오류를 줄일 수 있다. 그리고 동일한 크기의 지연 큐를 가지고도 웜 탐지시간을 줄이고 웜 패킷 전송 수를 줄일 수 있는 가중치 평균 큐 길이 기반의 새로운 웜 탐지 알고리즘을 제안한다. 지연 큐 길이 산정 시 현재의 큐 길이 뿐 아니라 과거의 큐 길이를 반영하는 방법이 웜의 발생 가능성을 사전에 예측하여 기존 기법보다 빠르게 웜을 탐지할 수 있음을 실험을 통해 확인하였다. Since the propagation speed of the Internet worms is quite fast, worm detection in early propagation stage is very important for reducing the damage. Virus throttling technique, one of many early worm detection techniques, detects the Internet worm propagation by limiting the connection requests within a certain ratio.[6, 7] The typical throttling technique increases the possibility of false detection by treating destination IP addresses independently in their delay queue managements. In addition, it uses a simple decision strategy that determines a worn intrusion if the delay queue is overflown. This paper proposes a two dimensional delay queue management technique in which the sessions with the same destination IP are linked and thus a IP is not stored more than once. The virus throttling technique with the proposed delay queue management can reduce the possibility of false worm detection, compared with the typical throttling since the proposed technique never counts the number of a IP more than once when it chicks the length of delay queue. Moreover, this paper proposes a worm detection algorithm based on weighted average queue length for reducing worm detection time and the number of worm packets, without increasing the length of delay queue. Through deep experiments, it is verified that the proposed technique taking account of the length of past delay queue as well as current delay queue forecasts the worn propagation earlier than the typical iuぉ throttling techniques do.

국가물류 정보화 추진방향

심재홍,Sim, Jae-Hong 한국물류협회 2005 물류혁신 컨퍼런스 Vol.13 No.1

다중 공유 링크들의 공정한 대역폭 분배를 위한 세션할당 알고리즘

심재홍,최경희,정기현,Shim, Jae-Hong,Choi, Kyung-Hee,Jung, Gi-Hyun 한국정보처리학회 2004 정보처리학회논문지 C : 정보통신,정보보안 Vol.11 No.2

본 논문에서 다중 공유 링크들을 가진 스위치를 위한 세션할당 알고리즘을 제안한다. 제안 알고리즘은 서비스 클래스들에게 사전에 예약된 대역폭을 보장하고, 동일한 서비스 클래스에 속한 세션들에게는 서로 다른 공유 링크를 통해 전송되어도 가능한 비슷한 지연을 제공하고자 한다. 이러한 QoS를 제공하기 위해 다중 공유 링크를 위한 새로운 스케줄링 모델을 정의하고, 이를 기반으로 새로운 세션의 연결 설정 시 이를 어떤 공유 링크에 할당할 것인지를 결정하는 경험적 세션할당 알고리즘을 제안한다. 제안된 알고리즘은 새로운 세션이 소속된 서비스 클래스의 각 링크에 할당된 세션들의 예측된 지연들 중 가장 작은 예측 지연을 가진 링크에게 새로운 세션을 할당한다. 모의실험을 통해 제안 알고리즘을 채택한 스위치가 다른 세션할당 알고리즘을 채택한 스위치에 비해 서비스 클래스들에게 보다 공정한 대역폭을 할당하고 높은 패킷 처리율을 제공하며 예약된 대역폭을 보다 확실히 제공한다는 것을 확인할 수 있었다. 또한 동일한 서비스 클래스의 세션들에게 보다 비슷한 서비스 지연을 제공한다는 것도 확인했다. In this paper, a session allocation algorithm for a switch with multiple shared links is proposed. The algorithm guarantees the reserved bandwidth to each service class and keeps the delay of sessions belonging to a service class as close as possible even if the sessionsare allocated to different shared links. To support these qualities of services, a new scheduling model for multiple shared links is defined and a session allocation algorithm to decide a shared link to be allocated to a new session on the connection establishmentis developed based on the model. The proposed heuristic algorithm allocates a session to a link including the subclass with the shortest (expected) delay that subclasses of the service class the session belongs to will experience. Simulation results verify that a switch with multiple shared links hiring the proposed algorithm provides service classes with fairer bandwidth allocation and higher throughput, and guarantees reserved bandwidth better than the switch hiring other session algorithms. It also guarantees very similarservice delay to the sessions in the same service class.

태스크 선택정책에 기반을 둔 IRIS 태스크 스케줄링 알고리즘

심재홍,최경희,정기현,Shim, Jae-Hong,Choi, Kyung-Hee,Jung, Gi-Hyun 한국정보처리학회 2003 정보처리학회논문지 A Vol.10 No.3

본 논문에서는 IRIS(Increasing Reward with Increasing Service) 태스크들을 위한 기존 온-라인 최적 알고리즘에 근접한 총가치(total reward)를 생성하면서 보다 낮은 스케줄링 복잡도를 가진 휴리스틱(heuristic) 온-라인 스케줄링 알고리즘을 제안한다. 기존 알고리즘들은 총가치를 최대화하기 위해 시스템 내의 모든 태스크들을 스케줄링 대상으로 고려한다. 따라서 이들 알고리즘들은 많은 태스크들을 가진 실제 시스템에 적용하기에는 매우 놀은 시간 복잡도를 가진다. 제안 알고리즘은 시스템 내의 모든 태스크들을 대상으로 스케줄링하는 것이 아니라, 상수 W개의 태스크들을 선택하여 이들을 대상으로 스케줄링 한다. 제안 알고리즘은 W개의 태스크를 어떤 기준에 의해 선택할 것인가를 규정하는 테스크 선택정책에 기반을 두고 있으며, 간단하면서도 직관적인 두 가지 선택정책과 이 둘을 통합한 보다 일반화된 선택정책을 제안한다. 스케줄링 대상을 축소함으로써 제안 알고리즘의 복잡도를 O(Wn)로 줄일 수 있었다. 다양한 성능실험 결과 알고리즘 평균 계산 빈도는 O(W)에 더 가깝다는 것을 확인할 수 있었다. We propose a heuristic on-line scheduling algorithm for the IRIS (Increasing Reward with Increasing Service) tasks, which has low computation complexity and produces total reward approximated to that of previous on-line optimal algorithms. The previous on-line optimal algorithms for IRIS tasks perform scheduling on all tasks in a system to maximize total reward. Therefore, the complexities of these algorithms are too high to apply them to practical systems handling many tasks. The proposed algorithm doesn´t perform scheduling on all tasks in a system, but on (constant) W´s tasks selected by a predefined task selection policy. The proposed algorithm is based on task selection policies that define how to select tasks to be scheduled. We suggest two simple and intuitive selection policies and a generalized selection policy that integrates previous two selection policies. By narrowing down scheduling scope to only W´s selected tasks, the computation complexity of proposed algorithm can be reduced to O(Wn). However, simulation results for various cases show that it is closed to O(W) on the average.

부정확한 계산 모델을 위한 커널의 지원 ( O . S . Support for Imprecise Computation )

심재홍,심찬배,최현창,최경희,정기현,김동윤 대한전자공학회 1996 대한전자공학회 학술대회 Vol.1996 No.7

Aeroelastic Response of an Airfoil-Flap System Exposed to Time-Dependent Disturbances

심재홍,나성수,Chan-Hun Chung 대한기계학회 2004 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.18 No.4

Aeroelastic response and control of airfoil-flap system exposed to sonic-boom, blast and gust loads in an incompressible subsonic flowfield are addressed. Analytical analysis and pertinent numerical simulations of the aeroelastic response of 3-DOF airfoil featuring plunging-pitching-flapping coupled motion subjected to gust and explosive pressures in terms of important characteristic parameters specifying configuration envelope are presented. The comparisons of uncontrolled aeroelastic response with controlled one of the wing obtained by feedback control methodology are supplied, which is implemented through the flap torque to suppress the flutter instability and enhance the subcritical aeroelastic response to time-dependent excitations.

뇌동맥류에 대한 현미경 수술

심재홍,김형동 인제대학교 1981 仁濟醫學 Vol.2 No.3

뇌졸증 중 많은 비중을 차지하는 뇌동맥류의 효과적인 치료방법을 찾기 위해서 저자들은 수술현미경 하에서 외과적 수술요법을 시도한 뇌동맥류 52례에 대한 임상분석과 문헌고찰을 하였다. The author analyzed 84 cases of supratentorial aneurysm in the Department of Neurosurgery Busan Paik's Hospital, In Je medical collage, from June 1979 to July 1981. Of the 84 cases, 52 cases were undergone direct intracranial approach (neck clipping, trapping, coating, wrapping, proximal clipping and STA-MCA anastomoses after ligation of ICA) for the treatment of aneurysms. We studied about aneurysmal incidence, distribution of age, sex and site, symptoms and signs, preoperative condition, operation and result of operation, etc. Overall mortality rate for direct intracanial approach was 13.3% but surgical operative mortality was 4%. Various factors were influenced morbidity and mortality such as preoperative condition, age, times of interval, site, multiplicity and postoperative vasospasm and edema.

뇌동맥류 수술시기에 대한 수술 경험-수술시기-

심재홍,김수천 인제대학교 1995 仁濟醫學 Vol.16 No.3

저자들은 1980년부터 1993년 6월까지 본원에서 뇌동맥류 파열로 인해 입원한 환자 1409명 중 수술치험한 1000례를 대상으로 수술시기에 따른 수술방법, 수술결과 및 합병증 등을 비교분석하여 문헌 고찰과 함께 보고하였다. The principle role of treatment for ruptured aneurysm has been to obliterate the aneurysmal sac and secure the patient's life from the hazards of rebleeding and vasospasm. The timing of surgery is still the focus of neurosurgical controversy Recently there has been a resurgence of interest in the early operation and increasing number of surgeon have been adopting this modality. The clinical material for this study consists of 1409 consecutive patients with ruptured aneurysm admitted to the Pusan Paik's hospital, School of Medicine, Inje University from January 1980 to June 1993. perations were performed in 1000 cases and 409 cases were not operated due to refusal of operation, moribund discharge after rebleeding and vasospasm, and medical problems, etc. In 1000 operative group, 383 cases were anterior communicating artery aneurysms, 304 internal canotid artery aneurysms, 256 middle cerebral artery aneurysms, 24 anterior cerebral artery aneurysms and 33 cases were verebrobasilar artery aneurysm. The operative cases were devided into 3 categories; the first is 456 operative cases in which the direct operation carried out within 3 days after last subarachnoid hemorrhage, and 86% had a favorable outcome, 7% died, the second is the 301 operative cases between 4 days and 10 days after last subarachnoid hemorrhage, 80% had favorable outcome, 10% died, and the last is 243 late operative cases performed greater than 10 days after subarachnoid hemorrhage, 84% had favorable outcome, 9% died. Overall surgical result was favorable outcome in 84% and 8% mortality. Most of the mortality and morbidity is related to initial insult of bleeding, rebleeding, vasospasm, surgical complications, and medical problems. In this study, the surgical timing and problems during operation for ruptured intracranial aneurysm are discussed.