• Proceedings of the KAIS Fall Conference
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• 2006.05a
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• pp.174-176
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• 2006

본 논문에서는 모터와 롤러에 의해 발생된 진동이 프레임에 전달되고 또한 롤러가 회전하면서 프레임에 진동을 전달하여 공진을 일으킬수 있으므로 프레임과 롤러의 고유진동수를 해석함으로서 진동발생 요인인 모터의 회전 주파수를 제어하고 진동에 대한 구조적 안전성을 평가하였다.

• Computational Structural Engineering
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• v.9 no.2
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• pp.16-22
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• 1996

스페이스 프레임의 설계과정에서 컴퓨터의 급진적인 진보와 많은 연구노력의 결과로 전체 설계과정이 통합자동화 방향으로 진행되고 있으며, 특히 구조해석과 구조설계분야에서 중요한 진보가 이루어져 왔다. 본문에서는 스페이스 프레임의 설계과정을 시스템화함에 있어서 자동화 방법론의 개괄적인 내용과 스페이스 프레임의 3차원적인 복잡한 형태를 표현하기 위한 Formex 대수학 (FORMEX ALGEBRA)의 적용사례에 대한 설명 및 후처리단계에서 해석결과치를 가지고 코드검토에 대한 규준식의 소개와 프로그램에 대한 내용을 설명한다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.3
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• pp.191-198
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• 2013

In this paper, the effects of uncertain material constant on the nonlinear behavior of steel frames with semi-rigid joints are examined. As to the probabilistic model, a normal distribution is assumed to simulate the uncertain elastic modulus of steel material. A nonlinear structural analysis program, which can consider both semi-rigidity in joints of the steel frames and uncertainty in the material constant, is developed. Including the geometric, material and connection nonlinearites which are the parameters of nonlinear behavior of steel frames, probabilistic analysis is conducted based on the Monte-Carlo simulation. In the probabilistic analyses, we consider the three different cases for random variables. The deterministic analysis results are shown to be in good agreement with those of the previous research results in the literature. As to the probabilistic analyses, it is observed that the coefficient of variation(COV) of displacements increases as the loading increases, and that the values of COV are dependent on the structural features of the frames.

• Journal of the Microelectronics and Packaging Society
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• v.8 no.4
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• pp.67-72
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• 2001

An Effort has been made to more accurately analyze the flow in the chip cavity, particularly to model the flow through the openings in the leadframe and correctly treat the thermal boundary condition at the leadframe. The theoretical analysis of the flow has been done by using the Hele-Shaw approximation in each cavity separated by a leadframe. The cross-flow through the openings in the leadframe has been incorporated into the Hele-Shaw formulation as a mass source term. The optimization program based on the complex method integrated with flow analysis program has been successfully used to obtain the optimal filling conditions to avoid short shot.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.5
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• pp.147-156
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• 2001

본 연구에서는 칩 캡슐화 성형 공정 중의 패들 변형을 해석하기 위한 방법론이 연구되었다. 헬레쇼오 근사 모델에 근거한 유한요소법이 칩 캐비티에서의 유동 해석을 위해 사용되었다. 리드 프레임 상의 구멍을 통한 통과 유동해석을 위한 근사모델이 제안되었다. 본 연구에서 제시된 해석모델에 의해 계산된 값과 실험 값은 잘 일치하였다. 유동해석을 통하여 리드프레임과 패들에 의해 경계를 이루고 있는 상, 하 캐비티간의 압력차가 계산되었다. 최종적으로 패들 변형이 압력차 계산 값을 이용하여 계산되게 된다.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.3
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• pp.230-235
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• 2004

This paper describes FPGA implementation of a pointer interpreter which can support a synchronization of SDH(or SONET)-based transmission network. The pointer interpreter consists of a pointer-word extractor and a pointer-word interpreter The pointer-word extractor which is composed of mod-6480 counter, shift register and pointer synchronizing block, finds out the H1 and H2 pointer word from a 51.84 Mb/s AU-3/STS-1 data frame and then performs the synchronizing with a 6.48 Mb/s by dividing them in 8. Based on the extracted pointer word, pointer-word interpreter analyzes pointer states such LOP, AIS and NORM according to pointer state-transition algorithm. It consists of a majority vote, a pointer word valid/invalid check, a pointer justification, and a pointer state check. The simulation results of Xilinx Virtex XCV200PQ240 FPGA chip shows the exact pointer word extraction and correct decision of pointer status based on extracted pointer word. The proposed pointer interpreter is suitable for pointer interpretation of 155 Mb/s STM-1/STS-3 frame.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.9
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• pp.2027-2034
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• 1997

Frame relay is a fast packet switching technology that performs relaying and multiplexing frames with variable lengths over a wide area link at the T1 or E1 speed, by elminating error and flow control in the network. In frame relay networks, congestion control is typically performed through the rate enforcement with a discard eligibility (DE) bit, and the explicit negative feedback meachanisms using explicit congetion notification bits. In this paper, we consider the congestiong control scheme using the rate enforcement mechanism with DE bit for frame relay network. Assuming that each frame with exponentially distributed length arrives according to the Poission fashion, we can treat the frame relay switch as an M/M/1/K priority queueing system with pushout basis. We analyze and present the blocking probabilities and waiting time distributions of frames.

• Korean journal of communication and information
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• v.71
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• pp.274-298
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• 2015

Doctoral Candidate, Department of Communication, Pusan National University This study analyzed the political and social significance of the disaster accident news with the frame and bias concept. In particular, this study confirmed theoretically how domestic media biased frame when it presents problem definition, causing interpretation, moral evaluation, and post-prescription on the ferry Sewol accident, In addition, the bias of the frame was analyzed comparing what is the difference between the conservative newspapers and liberal newspapers. Findings are as follows. First, in diagnosis of ferry Sewol accident, news slanted fragmentation frame>personalization frame>authority-disorder frame. The Chosun Ilbo focus on fragmentation bias, meanwhile Hankyoreh focus on the authority disorder relatively. Second, in accident evaluation, responsibility frame> moral frame> problem-solution frame. The Chosun Ilbo focus on responsibility frame and moral frame. But Hankyoreh focus on responsibility frame and problem-solution frame. Third, in the matter of responsibility, government frame>personal frame>organizational frame. Chosun Ilbo biased responsibility of the government and individuals, while the Hankyoreh is relatively more emphasis on government responsibility and the responsibility of the organization also showed. Fourth, in problem solving, thematic frame and episodic frame bias appeared as rough and level. Chosun Ilbo showed episodic frame, Hankyoreh showed thematic frame. News frame and bias as well as ideological differences of media on ferry Sewol accident was discussed in the context of the social dimension.

• Journal of the Korea Society for Simulation
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• v.24 no.3
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• pp.69-75
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• 2015

This research focuses on structural stability of the multi-aerial platform. In this study, we conduct structural analysis for the lower structures such as sub frame, out-trigger and chassis frame, by using a universal structural analysis program NASTRAN based on 3D CAD data, material properties, load conditions and boundary conditions. We confirm the position of local stress exceeding the yield strength, through structural analysis of 4 cases for load conditions. As the results, it is possible to relax stress concentration in a way such as changing the thickness, reinforcing the material of the lower frames.

• Computational Structural Engineering
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• v.10 no.4
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• pp.165-175
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• 1997

In this paper, the stress, buckling and vibration analyses have been performed for several case with the spot weld stiffened rear side frame, the unstiffened rear side frame and the dual thickness laser weld rear side frame. For stress and vibration analyses, the clamped boundary condition with spring supports are used. But for the buckling analyses, the both ends simply supported boundary conditions are used. For the nummerical analyses, ANSYS 5.0 code is adopted. Maximum stress of the spot weld stiffened rear side frame occurs in the main frame and is 80.9 MPa. Maximum strain is 501 .mu.. The maximum stress of the dual thickness laser weld rear side frame of 1.8mm thickness structure is equal with the stress of spot weld stiffened frame. The weight of dual thickness laser weld frame can be reduced about 17.2%. For the stiffened spot weld rear side frame with both ends simply supported boundary conditon, the bucking load is 52.54 kN. When the thickness of the dual thickness laser weld rear side frame become 1.9mm thickness structure, the buckling load of the stiffenerd rear side frame is equal to that of dual thickness laser weld frame. The reduction of the structure weight is about 5%. The fundamental natural frequency of the stiffened spot weld rear side frame for bending mode is 163.6 Hz and that of the dual thickness laser weld rear side frame is 179.8 Hz.