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과학자와의 만남 프로그램 적용이 초등학생의 과학자에 대한 신체적 이미지에 미치는 효과
김성관(Sung Kwan Kim),장명덕(Myoung Duk Jang),정진우(Jin Woo Jeong) 한국과학교육학회 2002 한국과학교육학회지 Vol.22 No.3
This study investigated the effects of the `Meeting With Scientists` program on children`s stereotypical images of scientist. To do those, 36 children of a fifth grade class participated in the program for one month. The program consisted of two main activities:(1) participating in scientists` lectures and exchanging e-mail with them; and (2) visiting web sites about scientist and science, and exchanging e-mail with scientists at the sites. The results of the study can be summarized as follows: First, after participating in the program, children showed the significant decrease of several stereotypical items, such as facial growth of hair(bald hair ·??beard), symbols of research, and age of the scientist. Second, the most popular source of the images was the visual media at the pretest but the source was changed to the visiting and participating scientist`s lecture, and internet at the posttest. The latter items appeared a significant difference between the pretest and the posttest. The results indicate that the program is effective to decrease of children`s stereotypical physical image of scientist.
MPLS 망에서 차별화 된 서비스를 제공하기 위한 빠른 Multipoint-to-Point LSP 결정 방식
김성관,조영종,Kim, Seong-Gwan,Jo, Yeong-Jong 대한전자공학회 2002 電子工學會論文誌-TC (Telecommunications) Vol.39 No.5
MPLS(Multiprotocol Label Switching) 망에서 LSP(Lable Switched Path)의 수와 레이블 수를 줄이는 것은 망의 자원 관리 측면에서 매우 중요하며, MTP(Multipoint-to-Point) LSP는 이러한 문제점을 해결할 수 있다. 트래픽 엔지니어링을 고려할 때, MTP LSP는 트래픽 부하의 균형을 통한 망의 가용성과 링크 사용율을 높이는 경로를 선택하여야 한다. 또한 링크 단절시의 재 경로 설정이 요구되므로 빠른 경로 결정 방법이 요구된다. 본 논문은 Diffserv를 지원하는 MPLS 망에서, Diffserv의 PHB(Per Hop Behavior)와 다중경로 MTP LSP간의 매핑을 통한 트래픽 엔지니어링을 제안한다. 제안하는 트래픽 엔지니어링은 서비스 특성에 따라 계층적인 MTP LSP의 다중 경로를 결정한다. Monte-Carlo 방법을 사용한 빠른 트래픽 부하 균형 해를 구함으로써, 망 형태 정보가 빈번히 변하는 대규모 망에서 신속한 재 경로 결정을 할 수 있다. 제안하는 MTP LSP의 경로 결정 방법은 알고리즘의 수행 정도에 따라 최적의 경로 결정에 접근한다. 경로 결정의 시간 복잡도는 O(Cn²logn)으로 기존의 다중 경로 결정 방법과 동일한 시간 복잡도를 가지며, 선형 프로그래밍 접근보다 빠른 수행 시간을 갖는다. 시뮬레이션 결과 제안하는 알고리즘은 망의 형태정보와 요구하는 트래픽 부하 균형에 따라 효과적으로 제어될 수 있음을 보이며, 또한 제안하는 트래픽 엔지니어링의 호 차단율과 대역폭 차단율을 비교함으로써 망의 가용성이 기존의 다중경로 설정보다 높음을 보인다. In a MPLS(Multiprotocol Label Switching) network, it is important to reduce the number of labels and LSP(Lable Switched Path)s for network resource management. MTP(Multipoint-to-Point) LSP can be used to solve this problem. In consideration of traffic engineering, MTP LSP must be chosen to enhance the availability of network and link utilization. Also, a fast mechanism to setup MTP LSPs is required for rerouting capability against link failure. In this paper, we propose a fast MTP LSP traffic engineering of multipath MTP LSP by using a mapping of a MTP LSP upon Diffserv PHBs(Per Hop Behavior) in a Diffserv-capable MPLS network. In the proposed traffic engineering, we determine multiple MTP LSPs in a hierarchical manner according to the characteristics of different services. By using Monte-Carlo method for traffic load balancing process, it provides fast rerouting capability in case of frequent link failure across large network. Out method produces to be nearly optimal within reasonable run-times. It's time complexity is in O( Cn$^2$logn) as conventional multipath routing and it is much faster than Linear Programming approach. Simulation results show that the proposed traffic engineering can be controlled effectively in an administrative manner and enhance the availability of network in comparison with conventional multipath routing.
김성관,곽효성,정경호,한영민 대한영상의학회 2011 Korean Journal of Radiology Vol.12 No.5
Objective: To evaluate the usefulness of percutaneous aspiration thromboembolectomy (PAT) via a transbrachial approach in patients with acute upper limb ischemia. Materials and Methods: From July 2004 to March 2008, eleven patients with acute upper limb ischemia were enrolled in this study. They were initially treated with thrombolysis (n = 1), PAT (n = 6), or both (n = 4) via a femoral artery approach. However, all of the patients had residual thrombus in the brachial artery, which was subsequently managed by PAT via the transbrachial approach for removal of residual emboli. Results: Successful re-canalization after PAT via a transbrachial approach was achieved in all patients. Two patients experienced early complications: one experienced a massive hematoma of the upper arm due to incomplete compression and was treated by stent deployment. The other patient experienced a re-occlusion of the brachial artery the day after the procedure due to excessive manual compression of the puncture site, but did not show recurrence of ischemic symptoms in the artery of the upper arm. Clinical success with complete resolution of ischemic symptoms was achieved in all patients. Conclusion: PAT via a transbrachial approach is a safe and effective treatment for patients with acute upper limb ischemia. Objective: To evaluate the usefulness of percutaneous aspiration thromboembolectomy (PAT) via a transbrachial approach in patients with acute upper limb ischemia. Materials and Methods: From July 2004 to March 2008, eleven patients with acute upper limb ischemia were enrolled in this study. They were initially treated with thrombolysis (n = 1), PAT (n = 6), or both (n = 4) via a femoral artery approach. However, all of the patients had residual thrombus in the brachial artery, which was subsequently managed by PAT via the transbrachial approach for removal of residual emboli. Results: Successful re-canalization after PAT via a transbrachial approach was achieved in all patients. Two patients experienced early complications: one experienced a massive hematoma of the upper arm due to incomplete compression and was treated by stent deployment. The other patient experienced a re-occlusion of the brachial artery the day after the procedure due to excessive manual compression of the puncture site, but did not show recurrence of ischemic symptoms in the artery of the upper arm. Clinical success with complete resolution of ischemic symptoms was achieved in all patients. Conclusion: PAT via a transbrachial approach is a safe and effective treatment for patients with acute upper limb ischemia.
경동맥 스텐트 삽입술에 의해 회복을 보인 관류저하성 치매
김성관,이수윤,강명진,박경원 대한치매학회 2008 Dementia and Neurocognitive Disorders Vol.7 No.2
Cortical hypoperfusion is related to cognitive and neuropsychiatric symptoms and signs. It is suggested that disruption of the frontal-subcortical circuit or perfusion deficits by remote vascular stenosis may play an important role in patients with vascular dementia. We report a case of acute hypoperfusion dementia that showed improvement of cognitive impairment and hemodynamic recovery after stent insertion. Extensive perfusion deficits caused by carotid artery stenosis with secondary hypometabolism in the hemispheric region may be a cause of reversible vascular dementia syndrome.