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DRM 기반의 콘텐츠 보호를 위한 패키징 알고리즘 설계
김상언 ( Sang Eun Kim ) 조선대학교 공학기술연구원 2009 공학기술논문지 Vol.2 No.4
In late 1990s as the internet-based digital content distribution industry emerged as a new business model, a plethora of DRM technologies were released to prevent copyright infringement due to illegal copies. However, as digital music and e-Books, which formed the early market for the DRM technologies, got stagnant; complaints of DRM product users, mostly copyright holders, increased; and disparate DRM technologies lacked in compatibility, the DRM technology has been used to a very limited extent and the DRM packaging technology currently in use mainly focuses on either security or user-friendliness. As a consequence, both security and user-friendliness are not met concurrently. In that sense, this study is to suggest a packaging mechanism for DRM systems that meets both features.
김상언(Sang-Eun Kim),한승조(Sung-Jo Han) 한국정보기술학회 2007 Proceedings of KIIT Conference Vol.2007 No.-
본 논문에서는 무선랜 환경하에서 인증 수행시에 발생하는 핸드오버지연을 개선시키고자 한다. 무선랜은 특성상 이동이 빈번하며, 그 때마다 완전인증을 수행하기 때문에 핸드오버지연이 발생하게 된다. 따라서, 이 핸드오버지연을 줄이는 안전하면서도 빠른 인증 기술이 요구된다. 무선단말이 현재의 AP를 벗어나 새로운 AP로 움직여도 핸드오프의 지연 없이 계속하여 통신할 수 있도록 현재 모바일 통신에서 사용되는 HMIPv6 프로토콜을 접목 시키고자 한다. HMIPv6 프로토콜에서의 이동 노드의 이동을 지역적으로 관리하기 위하여 새로운 구성요소인 MAP역할을 하는 AP관리 서버를 무선랜 망에 설치함으로서 AP들을 지역적으로 관리하여 무선단말이 AP간 이동을 할 때 발생하는 핸드오프를 줄일 수 있는 방안을 제안한다.
큰 진폭의 반복하중 조건에서 원자력구조 재료의 손상모드에 미치는 하중형태와 응력상태의 영향
김상언(Sang Eun Kim),김진원(Jin Weon Kim),김종성(Jong Sung Kim) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.4
대형 지진조건에서 원전 기기 및 설비는 하중제어와 변위제어가 복합된 형태의 반복하중을 받으며, 형상학적 특징으로 인해 변형과 손상이 발생되는 부위는 복잡한 응력상태를 갖는다. 이 경우에 손상모드와 형태가 단순하지 않고 하중과 응력상태에 의존하는 것으로 알려져 있다. 따라서, 본 연구에서는 큰 진폭의 반복하중 조건에서 원자력구조재료의 손상모드에 미치는 하중형태와 응력상태의 영향을 파악하기 위해서, 노치반경이 다른 2 종류 봉상시편을 이용하여 큰 진폭의 변형률제어 및 하중제어 반복하중 조건에서 반복 응력-변형률 시험을 수행하였다. 시험에는 SA508 Gr.1a 저합금강과 SA312 TP316 스테인리스강으로 제작된 시편이 적용되었으며, 시험은 상온과 316℃에서 준 정적 속도로 수행되었다. 시험 결과로부터 재료 종류와 시험온도, 그리고 노치반경 별로 큰 진폭의 하중제어 및 변형률제어 반복하중에 따른 응답 하중과 변위, 손상사이클, 그리고 손상모드를 파악하였다. 손상모드는 시험 후 시편의 파면분석을 통해 결정하였다. The components and structures of nuclear power plants (NPPs) are subjected to combined load- and displacement- controlled cyclic loads under excessive seismic loads, and the damaged regions under cyclic loads showed complex stress state due to their geometrical characteristics. In this case, it is known that the failure mode and pattern depend on the loading type and stress state. Thus, this study conducted cyclic stress-strain tests using notched-bar type specimen with two different notch radii under a large amplitude strain- and load-controlled cyclic loads, and investigated the effect of loading type and stress state on the failure mode of nuclear structural materials under a large amplitude cyclic load. The specimens of SA508 Gr.1a low-alloy steel and SA312 TP316 stainless steel were used in the test, and the tests were conducted at room temperature (RT) and 316℃ under a quasi-static rate. From the results, the response loads and displacements, failure cycles, and failure mode were investigated for different test materials, test temperatures, and notch radii under both large amplitude load- and strain-controlled cyclic loads. The failure mode was determined through SEM analysis of the fracture surface.
냉간가공된 TP304 스테인리스강 모재와 용접재를 이용한 반복 변형 및 손상 거동에 미치는 중성자조사 영향 모사
김상언,김진원,Kim, Sang Eun,Kim, Jin Weon 한국압력기기공학회 2020 한국압력기기공학회 논문집 Vol.16 No.2
This study presents cyclic stress-strain and tensile test results at room temperature (RT) and 316℃ using cold-worked TP304 stainless steel base and weld metals. By comparing the cyclic hardening/softening behavior and failure cycle of cold-worked materials with those of irradiated austenitic stainless steels, the feasibility of simulating the irradiation effect on cyclic deformation and failure behaviors of TP304 stainless steel base and weld metals was investigated. It was found that, in the absence of strain-induced martensite trasformation, cold-working could properly simulate the change in cyclic hardening/softening behavior of TP304 stainless steel base and weld metals due to neutron irradiation. It was also recognized that cold-working could adequately simulate the reduction in failure cycles of TP304 stainless steel base and weld metals due to neutron irradition in the low-cycle fatigue region.
가진실험을 통한 배관 엘보우의 변형과 손상거동에 미치는 대형 지진하중의 영향 평가
홍진의(Jin Ney Hong),김진원(Jin Weon Kim),김상언(Sang Eun Kim),이대영(Dae Young Lee),박흥배(Heung Bae Park) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.11
Elbows in piping systems, which are designed to absorb energy by plastic deformation under an excessive external load, are vulnerable to cyclic deformation and related damage during beyond design basis earthquake (BDBE) events. Thus, understanding the deformation and failure behaviors of pipe elbows under large amplitude seismic loads is important to evaluate the structural integrity of piping system under BDBE condition. In this study, therefore, the present study performs excitation tests on elbow specimen using a shaking table under two types of input accelerations simulating excessive seismic loading. In the tests, two types of elbow materials were used and pressurized and unpressurized conditions were regarded. From the results, the effect of excessive seismic loads on the cyclic deformation and failure behaviors of pipe elbows for different elbow materials and internal pressures.
박종안(Jong-An Park),안영은(Young-Eun An),오상언(Sang-Eon Oh),김국정(Guk-Jeong Kim),이강준(Kang-Jun Lee) 한국정보기술학회 2017 한국정보기술학회논문지 Vol.15 No.8
Time consumed in cooking and spice distribution are common stress for modern people. In this paper, we proposed a recipe creator application that automatically mixes spice and generate a control signal to solve this problem. The proposed creator application implemented a service environment by communicating with the web view of the Android-based native app and the web server. In addition, according to the characteristics of the library of the endpoint supporting the Bluetooth communication in the existing activity unit, it is necessary to make a Bluetooth connection with each activity that exists by each recipe menu. This is accomplished to improve the view structures by applying fragments to replace activities, and is accomplished by implementing the data bridge that supports data communication between native apps and the web. Experimental results showed that the Bluetooth communication environment in the creator application is lasted to all activities through only once connection.