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안전한 SCADA 통신을 위한 트리 기반의 효율적인 키 관리 구조
최동현,이성진,정한재,강동주,김학만,김경신,원동호,김승주,Choi, Dong-Hyun,Lee, Sung-Jin,Jeong, Han-Jae,Kang, Dong-Joo,Kim, Hak-Man,Kim, Kyung-Sin,Won, Dong-Ho,Kim, Seung-Joo 한국정보처리학회 2009 정보처리학회논문지 C : 정보통신,정보보안 Vol.16 No.1
The SCADA(Supervisory Control And Data Acquisition) system is a control system for infrastructure of nation. In the past, the SCADA system was designed without security function because of its closed operating environment. However, the security of the SCADA system has become an issue with connection to the open network caused by improved technology. In this paper we review the constraints and security requirements for SCADA system and propose advanced key management architecture for secure SCADA communications. The contributions of the present work are that our scheme support both message broadcasting and secure communications, while the existing key management schemes for SCADA system don't support message broadcasting. Moreover, by evenly spreading much of the total amount of computation across high power nodes (MTU or SUB-MTU), our protocol avoids any potential performance bottleneck of the system while keeping the burden on low power (RTU) nodes at minimal. SCADA(Supervisory Control and Data Acquisition) 시스템은 국가 기반시설에서 주로 사용되는 제어 시스템이다. 과거 SCADA 시스템은 폐쇄 망에서 운영되어진다는 이유로 보안에 대한 고려 없이 설계되었다. 하지만 기술의 발달로 SCADA 시스템과 공용망과의 연계가 추진되면서 보안에 대한 문제점이 대두 되고 있다. 본 논문에서는 SCADA 시스템의 제약사항과 보안요구사항을 살펴보고, 안전한 SCADA 시스템을 위한 키 관리 구조를 제안한다. 기존에 제안되어있는 SCADA 시스템을 위한 키 관리 방식이 메시지 브로드캐스팅을 지원하지 못하는 반면, 제안하는 방식은 메시지 브로드캐스팅을 지원한다. 또한 제안하는 방식은 성능상의 제약을 가지고 있는 RTU의 계산량을 최소화하기 위해, 상위 노드(SUB-MTU 또는 MTU)에 계산량을 분배하여 RTU의 잠재적인 성능 병목을 해결하였다.
The Role of Paternal Drinking Problems in the Psychological Characteristics of High School Students
최동현,김종성,정진규,류영일,김영석,허원철 대한가정의학회 2013 Korean Journal of Family Medicine Vol.34 No.6
Background: It has been reported that children with parental drinking problems are at increased risk of drinking problems or psychiatric diseases in adulthood. The present study was conducted to examine the psychiatric characteristics of high school students according to paternal drinking problems.Methods: The subjects were 950 high school students (390 male and 560 female). The paternal drinking problems were assessed by using the Father-Short Michigan Alcoholism Screening Test. The Alcohol Use Disorders Identification Test, Beck’s depression inventory, and Beck’s anxiety inventory were used to evaluate the drinking behavior, depression, and anxiety of high school students.Results: While male students with paternal drinking problems showed significantly increased risk of anxiety (odds ratio [OR], 2.21; 95% confidence interval [CI], 1.05 to 4.63), female students with paternal drinking problems showed significantly increased risk of depression (OR, 1.84; 95% CI, 1.24 to 2.74) according to the results of logistic regression analysis with adjustments for participants’ age, whether they live together with parents, their religion, club activities, and smoking habits on the basis of students without paternal drinking problems.Conclusion: The above results suggest that paternal drinking problems lead to unstable mentalities in both male and female students, and that a family physician should address the mental state of teenagers with paternal drinking problems during clinical encounters.
광학식 유도장치를 이용한 자율 무인잠수정의수중 도킹 알고리즘에 관한 연구
최동현,전봉환,이판묵,김상현,임근남 한국해양공학회 2007 韓國海洋工學會誌 Vol.21 No.3
The more deeply the researches make progress in ocean researches including the seabed resource investigation or the oceanic ecosystem investigation, the more important the role of UUV gets. In case of study on the deep sea, there are difficulties in telecommunications between AUV and ships, and in data communication and recharging. Therefore, docking is required. In AUV docking system, the AUV should identify the position of docking device and make contact with a certain point of docking device. MOERI (Maritime & Ocean Engineering Research Institute), KORDI has conducted the docking testing on AUV ISIMI in KORDI ocean engineering water tank. As AUV ISIMI approachs the docking device, there is some cases of showing an unstable attitude, because the lights which is on Image Frame are disappeared. So we propose the docking algorithm that is fixing the rudder and stern, if the lights on image frame are reaching the specific area in the Image Frame. Also we propose the new docking device, which has a variety of position and light number. In this paper, we intend to solve the some cases of showing an unstable attitude that were found in the testing, which, first, will be identified the validity via simulation.1. 서 론
최동현,원동호,김승주,Choi, Dong-Hyun,Won, Dong-Ho,Kim, Seung-Joo 한국정보보호학회 2010 情報保護學會誌 Vol.20 No.5
지구 온난화와 같은 환경 문제와 에너지 소비 증가에 따른 에너지 확보의 어려움에 많은 국가들이 어려움을 격고 있다. 이러한 에너지 확보 문제와 지구 온난화라는 문제를 해결할 수 있는 방법으로 제안된 것이 스마트 그리드 (Smart Grid) 이다. 스마트 그리드란 기존 전력망에 IT기술을 접목하여 공급자와 소비자가 양방향으로 실시간 전력정보를 교환함으로써 에너지 효율을 최적화하는 전력망이다. 기존의 폐쇄이던 전력망이 다양한 이해당사자가 참여하는 상호운용성이 보장되는 개방형 구조를 가지게 됨으로써 이에 대한 보안 기술 개발이 시급한 상태이다. 따라서 본고에서는 이러한 스마트 그리드 환경에 대해 설명하고 이러한 환경에서의 안전한 키 관리 기술에 대한 동향을 살펴본다.
Risk Factors for Anastomotic Leakage after Laparoscopic Rectal Resection
최동현,황재관,고용택,장한정,신현근,이영찬,임청호,정승규,양형규 대한대장항문학회 2010 Annals of Coloproctolgy Vol.26 No.4
Purpose: The anastomotic leakage rate after rectal resection has been reported to be approximately 2.5-21 percent, but most results were associated with open surgery. The aim of this study was to identify risk factors and their relationship to the experience of the surgeon for anastomotic leakage after laparoscopic rectal resection Methods: Between March 2003 and December 2008, 156 patients underwent a laparoscopic rectal resection without a diverting ileostomy. The patients’ characteristics, the details of treatment, the intraoperative results, and the postoperative results were recorded prospectively. Univariate and multivariate analyses were applied to identify risk factors for anastomotic leakage. Results: The majority of operations were performed for malignant disease (n = 150; 96.2%), and 96 patients (61.5%) were males. Conversion to open surgery occurred in 1 case (0.6%). The anastomotic leak rate was 10.3% (16/156), and there were no mortalities. In the univariate analysis, tumor location, anastomotic level, intraoperative events, and operation time were associated with increased anastomotic leakage rate. In the multivariate analysis, anastomotic level (odds ratio [OR], 6.855;95% confidence interval [CI], 1.271 to 36.964) and operation time (OR, 8.115; 95% CI, 1.982 to 33.222) were significantly associated with anastomotic leakage. Conclusion: The important risk factors for anastomotic leakage after laparoscopic rectal resection without a diverting ileostomy were low anastomosis and long operation time. An additional procedure, such as diverting stoma, may reduce the anastomotic leakage if it is selectively applied in cases with these risk factors.