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IPv6 네트워크 환경에서 MCGA를 고려한 통합적인 보안관리 방안
오하영,채기준,방효찬,나중찬,Oh, Ha-Young,Chae, Ki-Joon,Bang, Hyo-Chan,Na, Jung-Chan 한국정보처리학회 2007 정보처리학회논문지 C : 정보통신,정보보안 Vol.14 No.1
32비트의 IPv4 주소고갈의 문제를 해결하고 보안과 QoS를 확실히 보장해 주기 위해 등장한 IPv6는 특성상 128비트로 증가된 주소공간과 네트워크를 효율적으로 관리하기 위한 주소체계, 이웃 탐색 및 주소 자동 설정 등 다양한 서비스 제공을 위해 노드와 라우터간의 주고받는 새로운 메시지들이 많이 추가되었다. 결과 IPv4에서 존재하던 공격은 물론 예측하지 못했던 새로운 공격들이 많이 등장하게 된다. IPv4에서 성공적으로 IPv6로 전환하기 위해 무엇보다 필요한 것은 안전하고 체계적인 보안 정책기반 아래 기존에 동작되고 있는 IPv4 호스트 및 라우터와 IPv6의 안전한 호환성이다. 따라서 관리자는 앞으로 도래 할 IPv6 네트워크 환경을 효율적으로 관리하기 위해서 다양한 측면에서 보안 문제를 도출하여 통합적인 보안 대응 방안을 설계해야 한다. 본 논문에서는 IPv4와 IPv6의 특성을 파악하고, IPv4/IPv6에서의 공격 측면에서 보안 취약성 분석 및 보안 문제를 도출하여 시스템 측면, IPv6 특성별 측면, 개선된 CGA인 MCGA (Modified Cryptographically Generated Address)의 제안을 통해 IPv6에서의 효율적인 보안 관리를 위한 통합적인 대응방안을 제시한다. IPv6 has appeared for solving the address exhaustion of IPv4 and for guaranteeing the problems of security and QoS. It occurs the unexpected new attacks of IPv6 as well as the existing attacks of IPv4 because of the increasing address space to 128bits and the address hierarchies for efficient network management and additions of the new messages between nodes and routers like neighbor discovery and auto address configuration for the various comfortable services. For the successful transition from IPv4 to IPv6, we should get the secure compatibility between IPv4 hosts or routers working based on secure and systematic policy and IPv6. Network manager should design security technologies for efficient management in IPv4/IPv6 co-existence network and IPv6 network and security management framework designation. In this paper, we inspected the characteristics of IPv4 and IPv6, study on security requirement for efficient security management of various attacks, protocol, service in IPv4/IPv6 co-existence and IPv6 network, and finally suggest integrated solution about security vulnerability of IPv6 network in considering of analysis of IPv6 system, host and application, IPv6 characteristics, modified CGA(MCGA).
오하영,오동진,김대중,강우헌,이방훈,김범,이숭구,허우성 대한신장학회 1999 Kidney Research and Clinical Practice Vol.18 No.3
Elevated serum leptin concentration can contribute to anorexia and poor nutrition in patients with chronic renal failure, since leptin is elevated in chronic renal failure patients with or without dialysis, especially in chronic ambulatory peritoneal dialysis(CAPD) patients. The aim of this study to find whether leptin can be removed by peritoneal dialysis(PD) and to analyze factors that can affect serum leptin concentration after start of CAPD by observing the changes of serum leptin shortly after start of CAPD and their correlations with body mass index(BMI), serum insulin concentration and residual renal function(Creatinine clearance+Urea clearance/2). Twenty patients who started CAPD during the observation periods were studied. Serum leptin concentration was measured before start of CAPD, 3-5 days and 1, 3 months after start of CAPD by RIA method. Simultaneously, body weight, serum insulin concentration and residual renal function were measured. Removal of leptin was assessed by measuring dialysate leptn concentration divided by average serum leptin concentration before and after peritoneal equilibration test(PET) to compensate for the circardian rhythm of leptin. Leptin was eliminated by PD with dialysate to serum ratio of leptin to be 0.16±0.07 which was comparable to removal of β2-microglobulin(0.14±0.06). The mean serum leptin concentration did not decrease after 3-5 days of CAPD(8.4±13.1±11.9±18.0) despite its removal by PD and increased markedly 189%, 260% of basal serum leptin concentration on 1 month and 3 months after start of PD, respectively. Correlation coefficients(Spearmann's) between changes of serum leptin concentration and changes of BMI, serum insulin concentration, residual renal function were 0.267(P$gt;0.05, n=20), 0441(P$gt;0.05, n= 16), 0.706(P$gt;0.05, n=8) respectively. Leptin was removed by peritoneal dialysis. Serum leptin concentration did not decrease in 5 days after start of PD despite its removal by PD, and increased markedly 3 months after start of PD. We could not find signi correlation between changes of serum leptin concentration and changes of BMI. Factors other than fat mass gain can stimulate leptin increase shortly after start of PD.
체렌코프 복사와 광전자 증배관을 이용한 뮤온검출기 제작 및 납에 의한 뮤온 차폐 효과 연구
오하영,우재현,이해원 한국물리학회 2018 새물리 Vol.68 No.5
Cherenkov radiation originating from charged particles moving fast in water can be detected by using photoelectron multiplier tubes. Using this fact and apparatuses easily obtained from the Physics Department, we were able to build a muon detector for educational purposes. With this detector, we tried to detect muons reaching Earth's surface from above. The kinetic energy of the muons decreases as they move in lead materials. Using the detector, we investigated how the number of muon signals varies with the shield thickness and the ways of placing the lead shields. 빠른 전하입자가 물 속을 통과할 때 발생하는 체렌코프 광을 광전자증배관(photoelectron multiplier tube, PMT)으로 검출할 수 있다. 이 현상을 이용하여 비싼 기기 대신 물리학과에서 어렵지 않게 구할 수 있는 기기 만으로 교육용으로 사용할 수 있는 뮤온검출기를 자작(do-it-yourself, DIY)하였다. 또한 이 뮤온 검출기를 사용하여 대기에서 발생하여 지상에 도달하는 뮤온을 간접적으로 확인하고자 하였다. 뮤온은 밀도가 높은 물질인 납(lead)을 통과할 때 운동에너지가 감소하는 것으로 알려져 있다. 따라서 검출기를 이용하여 납 차폐체의 두께와 배치 방향에 따른 뮤온 신호의 변화를 알아보는 실험을 하였다. 이 실험을 통해 납 두께가 두꺼워지면 신호가 감소하고 배치방향에 따라서도 신호가 달라지는 것을 확인하였다.
오하영,오동진,김범,이숭구,김윤구,강우헌,이방훈,김혜영,허우성,김대중 대한신장학회 1998 Kidney Research and Clinical Practice Vol.17 No.6
We evaluated gastric emptying time(GET) by using Tc99m-sulfur colloid gastric emptying scintigraphy in 11 patients with CAPD(6 male, 5 female) and 14 healthy volunteers. We investigated the effect of dialysate dwelling on GET by studying twice, once without dialysate in the abdomen(drained) and once with 2 L of dialysate in the abdomen(full), and the relationship between body surface area(BSA) and delayed gastric emptying. 1) The mean of gastric emptying rate in 120 minute in patients with CAPD when drained(67.8±13.4%) was not different from that in healthy volunteers(65.4±8.6%) 2) The mean of gastric emptying rate in 120 minute when full(55.6±14.6%) was significantly lower than that when drained(67.8±13.4%)(P$lt;0.05). In four of the 11 patients(36.4%), gastric emptying was extremely delayed from normal to abnormal range when full. 3) The BSA(1.5±0.11m2)of patients who had extremely delayed GET from normal to abnormal range was smaller than that(1.74±0.22m2) of patients who had minimal delayed or unchaET when full. This study showed the patient with CAPD had normal gastric emptying when drained, and that gastric emptying was delayed by dialysate dwelling, especially in the patients who has less than 1.5m2 of body surface area. Therefore, we suggest that intermittent nocturnal peritoneal dialysis or a small volume of dialysate may be considered for the patient with small body surface area based on the adequacy.
Trend Analysis of Malwares in Social Information Based Android Market
오하영,구은희 한국정보보호학회 2017 정보보호학회논문지 Vol.27 No.6
As the use of smartphones and the launch of various apps have increased rapidly, the number of malicious apps has also increased, and the damage is continuing. The Google Market where Android apps are registered is inevitably present at the same time as normal apps and malicious apps even though there are regulations for app registration. Especially, as social networks are activated, users are connected with social networks, and the ratings, downloads and awareness information are reflected in the number of downloaded apps. As a result, when users choose their apps by simply reflecting ratings, popularity, popular comments, and highly-categorized apps, malicious app downloads can sometimes cause significant harm. Therefore, this study first analyzed the tendency of malicious apps by directly crawling and analyzing long-term social information in the currently active Android market.