• 한국컴퓨터정보학회논문지
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• 제24권8호
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• pp.67-76
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• 2019

Along with the diversification of digital content services using wired/wireless networks, the market for the construction of base systems is growing rapidly. Cloud computing services are recognized for a reasonable cost of service and superior system operations. Cloud computing is convenient as far as system construction and maintenance are concerned; however, owing to the security risks associated with the system construction of actual cloud computing service, the ICT(Information and Communications Technologies) market is lacking regardless of its many advantages. In this paper, we conducted an experiment on a cloud computing security enhancement model to strengthen the security aspect of cloud computing and provide convenient services to the users. The objective of this study is to provide secure services for system operation and management while providing convenient services to the users. For secure and convenient cloud computing, a single sign-on (SSO) technique and a system access control technique are proposed. For user authentication using SSO, a security level is established for each user to facilitate the access to the system, thereby designing the system in such a manner that the rights to access resources of the accessed system are not abused. Furthermore, using a user authentication ticket, various systems can be accessed without a reauthorization process. Applying the security technique to protect the entire process of requesting, issuing, and using a ticket against external security threats, the proposed technique facilitates secure cloud computing service.

• 인터넷정보학회지
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• 제6권2호
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• pp.84-97
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• 2005

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1350-1354
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• 2004

This paper proposes a simple but practically useful model for preventing fraud of users called "ERBAC03". The new model consists of qualified mandatory and discretionary features for roles and locations, including the assignment of permissions for the appropriate roles and the assignment of roles for the appropriate locations. Moreover, a static separation of duty (SSoD) principle is applied to the new model for integrity requirements of security systems. The paper also explores some extensions of ERBAC03 including the new model using the SSoD concept from some experiments. The experimental results prove the efficiency improvement of the proposed model that can make benefits for large enterprises.

• 대한견주관절학회:학술대회논문집
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• 대한견주관절학회 2009년도 제7차 연수강좌
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• pp.29-33
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• 2009

단순촬영에서 견관절을 이루는 골격의 형태를 파악하고 MRI에서는 주로 회전근 개 건의 fraying및 파열, 오훼견봉인대의 견봉 부착부위의 fraying, 점액낭염, 활막염, 관절순의 병변, 연골연화와 같은 연부조직의 병변을 관찰한다. 회전근 개 파열의 고식적 MR 진단은 정확도가 93%, 민감도가 84~100%, 특이도가 88~97%, 지방억제 MR 관절강 조영술은 민감도 및 특이도가 90%및 75%에서 100%까지 최근 보고 되고 있다. 단순촬영검사로 충돌중후군의 일반적인 소견을 파악할 수 있고 impingement series에는 견관절 전후면, suprascapular outlet view (SSO), craniocaudal 30 degree tilt view (CC30T), axillary view를 포함한다. 특히 SSO에서 견봉 및 ACJ의 형태 및 골극의 유무를 파악하고, CC30T에서는 견봉 돌출의 정도를 파악할 수 있다. 최근 고해상도의 MDCT로서 얻은 3차원 영상이 충돌증후군의 전반적인 영상 소견을 파악할 수 있고 수술전 평가에 이용되고 있다. MRI 및 MR Arthrography의 영상은 일반적으로 극상건의 주행에 따른 고식적 MR 사위 관상면이 중요하고 사위 시상면에서 견봉돌기의 형태와 대결절에 부착되는 극상건의 파열 유무와 정도를 파악할 수 있다. MR 관절조영술 후 외전 및 외회전후 (ABER view)의 영상도 관절면 쪽으로 부분 파열된 극상건의 진단에 유용하다.

• 전자공학회논문지
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• 제50권1호
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• pp.97-101
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• 2013

There is a growing need for optical communication systems that convert large volumes of data to optical signals and that accommodate and transmit the signals across long distances. Digital optical communication consists of a master unit (MU) and a slave unit (SU). The MU transmits data to SU using digital optical signals. However, digital optical units that are commercially available or are under development transmit data using two's complement representation. At low input levels, a large number of SSOs (simultaneous switching outputs) are required because of the high rate of bit switching in two's complement, which thereby increases the power noise. This problem reduces the overall system capability because a DSP (digital signal processor) chip (FPGA, CPLD, etc.) cannot be used efficiently and power noise increases. This paper proposes a change from two's complement to a more efficient method that produces less SSO noise and can be applied to existing digital optical units.

• 천문학논총
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• 제30권1호
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• pp.31-38
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• 2015

We develop a real-time data transfer system for the Korea Microlensing Telescope Network (KMTNet) photometry data and test whether it is suitable for Korea Astronomy and Space Science Institute (KASI) and three different observatories, which are Cerro Tololo Inter-Ameriacan Observatory (CTIO) in Chile, Siding Springs Observatory (SSO) in Australia, and South African Astronomical Observatory (SAAO) in South Africa. For this test, we use a high speed global network being dedicated for researches. From the test, we obtain that the elapsed times between KASI and each three observatories, CTIO, SSO, and SAAO to transfer 650 MB of data are 99.0, 9.2, 119.0 seconds, respectively. This means that the system can be used for the real-time data processing of KMTNet.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2003년도 춘계학술발표논문집 (하)
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• pp.2053-2056
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• 2003

인터넷 사용자들의 다양한 요구에 따라 존재하는 많은 자원들에 접근하기 위해 이용되었던 기존의 개별적인 인증절차는 패스워드 관리와 보관 피리고 공개된 네트워크를 통해 빈번히 전송되어지는 보안상의 취약점이 노출되어있다. 단일인증을 통해 보다 효율적이고 안전하게 필요한 자원에 접근하는 방법으로 SAML인증을 적용한 Single Sign On모델을 구현하였다.

• Structural Engineering and Mechanics
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• 제54권3호
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• pp.453-474
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• 2015

A hybrid approach of Particle Swarm Optimization (PSO) and Swallow Swarm Optimization algorithm (SSO) namely Hybrid Particle Swallow Swarm Optimization algorithm (HPSSO), is presented as a new variant of PSO algorithm for the highly nonlinear dynamic truss shape and size optimization with multiple natural frequency constraints. Experimentally validation of HPSSO on four benchmark trusses results in high performance in comparison to PSO variants and to those of different optimization techniques. The simulation results clearly show a good balance between global and local exploration abilities and consequently results in good optimum solution.

• KIEE International Transactions on Power Engineering
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• 제4A권4호
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• pp.178-191
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• 2004

This paper presents a new approach to HVDC system control for damping subsynchronous oscillation (SSO) involving HVDC converters and turbine generator shaft systems. This requires a novel eigenvalue analysis (NEA) program, derivation of HVDC system modeling considering steady-state conditions and dynamic conditions in the combined AC/DC system, and an appropriate control scheme. The method suggested makes possible the design of a subsynchronous oscillation damping controller (SODC) to provide positive damping torque for the range of torsional modes in combined AC/DC systems. There are three steps involved in the design of a SODC； first the worst torsional mode is determined using the NEA program, next the SODC parameters are designed for the range of that torsional mode, and then finally an off-line simultaneous time domain program such as PSCAD/EMTDC is used to verify the parameters of the SODC. The suggested SODC design method is applied to two AC/DC systems, and its practicality is verified using the PSCAD/EMTDC simulation program.

• 한국항공우주학회지
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• 제49권12호
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• pp.997-1010
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• 2021

본 연구는 스페이스 X사의 팔컨 9 발사체의 비행 데이터를 수집하였고 분석하였다. 모든 임무는 극궤도, SSO, ISS, LEO, GTO와 같은 궤도의 종류에 따라 분류하였다. 1단 발사체의 메인 엔진 종료, 역추진, 재진입, 착륙 연소의 특징적인 기동에서 속도, 고도, 동압, 가속도 등의 물리 변수의 변화를 조사하였다. 상세한 기동 분석으로부터 가이드라인을 제안하였고 이는 재사용 발사체 개발을 위한 설계 및 평가 기준으로 사용될 수 있다.