• Aerospace Engineering and Technology
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• v.12 no.2
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• pp.1-6
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• 2013

A LEO satellite transmits recorded images to a ground station using an X-band antenna during contact. The X-band antenna points to the ground station according to a TPF (tracking parameter file) during communication time. A TPF generation software generates azimuth and elevation profile which make the antenna point to the ground station using satellite orbit and attitude information and mission information including recording and downlink operation. When the satellite passes above the ground station, azimuth velocity increases rapidly so that jitter may occur if the azimuth velocity is in specific range. In case of realtime mission in which the satellite perform recording and downlink simultaneously, azimuth velocity must be lower than specific value to prevent image blur due to jitter effect. The method to point one virtual ground station has limitation of azimuth velocity reduction. In this paper, we propose the azimuth fixing method to reduce azimuth velocity of X-band antenna. The experimental results show that azimuth velocity of the X-band antenna is remarkably reduced using proposed method.

• International Journal of Internet, Broadcasting and Communication
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• v.11 no.3
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• pp.8-19
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• 2019

Since their emergence in 2007, smart phones have advanced up to the point that 5G mobile communication in 2019 started to be commercialized. Accordingly, now it is possible to share 3D modeling files and collaborate by means of a mobile web. As the recently commercialized 5G mobile communication network is so useful in sharing 3D modeling files and collaborating that even large-size geometry files can be transmitted at ultra high speed with ultra low transfer delay. We examines characteristics of major 3D file formats such as STL, OBJ, FBX, and glTF and compares the existing 4G LTE (Long Term Evolution) network with the 5G NR (New Radio) mobile communication network. The loading time and packets of each format were measured depending on the mobile web browser environments. We shows that in comparison with 4G LTE, the loading time of STL and OBJ file formats were reduced as much as 6.55 sec and 9.41 sec, respectively in the 5G NR and Chrome browsers. The glTF file format showed the most efficient performance in all of the 4G/5G mobile communication networks, Chrome, and Edge browsers. In the case of STL and OBJ, the traffic was relatively excessive in 5G NR and Edge browsers. The findings of this study are expected to be utilized to develop a 3D file format that reduces the loading time in a mobile web environment.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.1165-1168
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• 1998

This paper describes a 72-word by 32-bit 2-read/1-write multi-port register file, which is suitable for 32-bit RISC/DSP microprocessors. To minimize area and achieve high speed, advanced single-ended sense amplifiers are used. Each part of circuit is optimized at transistor level. The verification of functionality and timing is performed using HSPICE simulations. After modeling and validating the circuit at transistor level, it was laid out in a 0.6um 1-poly 3-metal layer CMOS technology. The simulation results show maximum operating frequency is 179MHz in worst case conditions. It contains 27,326 transistors and the size is 3.02mm by 2.20mm.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.221-224
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• 1998

Software release over the network is the most efficacious way of software update. Software release of electronic switching system, considering its environments, is the typical case that is in need of adopting the method. The media of transferring software and data of TDX-10A electronic switching system are magnetic tapes containing them, so the MT must be delivered between remotely placed office and package generation system. SMART-10A system provides the file tranfer on the data network between TDX-10A and the package generation system and ability of remote application of new software. This paper shows the implementation of file transfer between TDX-10A and computer system connected by data networks, status handling for duplicated system, and monitor process design with IPC on UNIX system.

• IEMEK Journal of Embedded Systems and Applications
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• v.5 no.3
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• pp.128-135
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• 2010

Recently complexity of embedded software cause to be used real-time operating system (RTOS) to implement various functions in the embedded system. And also, according to requirement of complex functions in embedded systems, the number as well as complexity of tasks get increased continuously. In case that many tasks collaborated in a microprocessor, context switching time between tasks is a overhead waisting a CPU resource. Therefore the time of task context switching is an important factor that affects performance of RTOS. In this paper, we concentrate on the improvement of task context switch for reducing overhead and achieving fast response time in RTOS. To achieve these goal, we suggest multiple register files and task context switching algorithm. By reducing the context switch overhead, we try to ease scheduling and assure fast response times in multitasking environment. As a result, the context switch overhead decreased by 8~16% depend on the number of register files, and some task set which are not schedulable with single register file are schedulable due to that decrease with multiple register files.

• International Journal of CAD/CAM
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• v.2 no.1
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• pp.55-67
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• 2002

In many areas of industry, it is desirable to have fast and reliable systems in order to quickly obtain suitable solid models for computer- aided analyses. Nevertheless it is well known that the data exchange process between CAD modelers and CAE packages can require significative efforts. This paper presents an approach for geometrical data exchange through triangulated boundary models. The proposed framework is founded on the use of STL file specification as neutral format file. This work is principally focused on data exchange among CAD modelers and FEA packages via STL. The proposed approach involves the definition of a topological structure suitable for the STL representation and the development of algorithms for topology and geometry data processing in order to get a solid model suitable for finite element analysis or other computer aided engineering purposes. Different algorithms for model processing are considered and their pros and cons are discussed. As a case study, a prototype modeler which supports an exporting filter for a commercial CAE package has been implemented.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.9 no.1
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• pp.39-52
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• 1998

The purpose of this study is to design the solution for creating full-text database of Korean dissertaion, After considering file formats for text based and image based database, Viewer, Search, Copy Right, Abstracts and Indexes, situation of Korea University Library, decided the principles of creating database. And suggested the design to produce the database for Korea University Library, that is easy to get file format conversion in case of the introducing new technology for the future.

• Proceedings of the Korean Society of Computer Information Conference
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• 2011.06a
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• pp.197-201
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• 2011

검찰과 경찰에서는 압수수색을 통해 조사를 수행하는데, 기업들은 압수수색 수사를 받기 전에 회계 DB 및 회계 관련 파일 삭제, 파손 및 은닉하는 등의 문제점을 발생시키고 있다. 2008년 삼성화재 비자금 조성 사건과, 2009년 교하 복합커뮤니티 센터의 입찰비리 사건 등 기업회계장부의 포렌식 기술적용방법 문제 등이 발생하고 있다. 본 논문에서는 포렌식 수사 도구인 EnCase, FinalData 등을 연구하고, 기업의 회계 서버에 대해 압수수색 준비와 압수 수색, 획득 증거 분석 등의 절차를 연구한다. 기업의 회계 서버 압수수색 후에 디스크에서 포렌식 증거분석에서 실시되는 증거물 원본 파일보관, 원본성이 입증된 사본생성, 삭제 파일 검사 및 복원, 삭제 내용 확인, 원본 파일과의 대조를 실험을 한다. 본 연구 결과는 포렌식 기술발전에 기여하게 될 것이다.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.6
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• pp.981-987
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• 1986

This paper describes the CIREX(CIRcuit EXtractor), an automated CMOS circuit extraction program which provides SPICE2 input file by computing circuit connectivity and transistor dimensions from the CIF file. The CIREX also computes parasitic capacitance and resistance which makes it a valuable tool for timing analysis and detailed circuit simulation. A lattice model is used to calculate the interconnection resistances and substrate capacitances which can be replaced, as an option, by a node model for the worst case timing analysis of the circuit.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.28 no.3
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• pp.243-251
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• 1992

The author examined the response of File fish, Stephanolepis Cirrhifer (TEMMINCK et SCHLEGEL) to the surface attracting lamps(0.5W, 0.8W, 1W) line in the experimental water tank (550L$\times$58W$\times$73H cm). the attracting rate was investigated in accordance with the interval of lighting and putting out hour (1, 5 minute)when each of the attracting lamps was gradually switched off after they were switched on all at once. The results are as follows: 1. Total distribution rate of fish in the illuminated section was 96.9%(mean 19.4%) in case of 1 minute interval, and 98.4%(mean 19.7%) in case of 5 minutes interval. 2. Mean distribution rate of fish at the illuminated section: \circled1 Distribution rate at interval of 1 minute were 19.9% in 0.8W, 19.3% in 1W and 18.9% in 0.5W respectively. \circled2 Distribution rate at interval of 5 minutes were 19.8% in 1W, 19.8% in 0.8W, and 19.5% in 0.5W respectively. 3. Attracting rate of the last section showed increasing as illuminating time elapse without interval and lighting source. 4. Attracting rate of fish in only last section switched on: \circled1 Attracting rate at interval in case of 1 minute were 98.0% in 1W, 97.0% in 0.5W and 83.0% in 0.8W respectively. \circled2 Attracting rate at interval in case of 5 minutes were 99.3% in 1W, 97.3% in 0.5W and 93.3% in 0.8W respectively.