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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal DOI :
Electronics and Telecommunications Research Institute
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Volume & Issues
Volume 22, Issue 4 - Dec 2000
Volume 22, Issue 3 - Sep 2000
Volume 22, Issue 2 - Jun 2000
Volume 22, Issue 1 - Mar 2000
Selecting the target year
Development and Testing of Satellite Operation System for Korea Multipurpose Satellite-I
Mo, Hee-Sook ; Lee, Ho-Jin ; Lee, Seong-Pal ;
ETRI Journal, volume 22, issue 1, 2000, Pages 1~1
The Satellite Operation System (SOS) has been developed for a low earth orbiting remote sensing satellite, Korea Multipurpose Satellite-I, to monitor and control the spacecraft as well as to perform the mission operation. SOS was designed to operate on UNIX in the HP workstations. In the design of SOS, flexibility, reliability, expandability and interoperability were the main objectives. In order to achieve these objectives, a CASE tool, a database management system, consultative committee for space data systems recommendation, and a real-time distributed processing middle-ware have been integrated into the system. A database driven structure was adopted as the baseline architecture for a generic machine-independent, mission specific database. Also a logical address based inter-process communication scheme was introduced for a distributed allocation of the network resources. Specifically, a hotstandby redundancy scheme was highlighted in the design seeking for higher system reliability and uninterrupted service required in a real-time fashion during the satellite passes. Through various tests, SOS had been verified its functional, performance, and inter-face requirements. Design, implementation, and testing of the SOS for KOMPSAT-I is presented in this paper.
Degradation Analysis of User Terminal EIRP and G/T due to Station-Keeping Variation of Stratospheric Platform
Ku, Bon-Jun ; Ahn, Do-Seob ; Baek, Dong-Cheol ; Park, Kwang-Ryang ; Lee, Seong-Pal ;
ETRI Journal, volume 22, issue 1, 2000, Pages 12~12
Wireless communication systems using airship have been proposed in worldwide. The airship will be located at the stratosphere about
above the sea level. The position of airship will vary within the station keeping range with time due to the drag of the wind in the stratosphere. When the earth station antenna has a high gain without the tracking function, the antenna performance may be degraded by a small variation of the airship. This means that variation of airship location could result in serious degradation of the system performance. In this paper, degradation in earth station's Equivalent Isotropic Radiated Power (EIRP) and Gain to noise Temperature ratio (G/T) due to the stratospheric platform movements has been derived by calculating the deviation angle of the main beam directions between the earth station and the platform antenna. In this case, the antenna of the earth station has been assumed circular and/or patch array antennas.
A Single-Chip Video/Audio CODEC for Low Bit Rate Application
Park, Seong-Mo ; Kim, Seong-Min ; Kim, Ig-Kyun ; Byun, Kyung-Jin ; Cha, Jin-Jong ; Cho, Han-Jin ;
ETRI Journal, volume 22, issue 1, 2000, Pages 20~20
In this paper, we present a design of video and audio single chip encoder/decoder for portable multimedia application. The single-chip called as video audio signal processor (VASP) consists of a video signal processing block and an audio single processing block. This chip has mixed hardware/software architecture to combine performance and flexibility. We designed the chip by partitioning between video and audio block. The video signal processing block was designed to implement hardware solution of pixel input/output, full pixel motion estimation, half pixel motion estimation, discrete cosine transform, quantization, run length coding, host interface, and 16 bits RISC type internal controller. The audio signal processing block is implemented with software solution using a 16 bits fixed point DSP. This chip contains 142,300 gates, 22 Kbits FIFO, 107 kbits SRAM, and 556 kbits ROM, and the chip size is
which is fabricated using 0.5 micron 3-layer metal CMOS technology.
Minimizing Cost and Delay in Shared Multicast Trees
Koh, Seok-Joo ; Yi, Jong-Hwa ; Hahm, Jin-Ho ; Chin, Byoung-Moon ; Park, Chee-Hang ;
ETRI Journal, volume 22, issue 1, 2000, Pages 30~30
Existing tree construction mechanisms are classified into source-based trees and center-based trees. The source-based trees produce a source-rooted tree with a low delay. However, for the applications with multiple senders, the management overheads for routing tables and resource reservations are too high. The center-based trees are easy to implement and manage, but a priori configuration of candidate center nodes is required, and the optimization mature such as tree cost and delay is not considered. In this paper, we propose a new multicast tree building algorithm. The proposal algorithm basically builds a non-center based shared tree. In particular, any center node is not pre-configured. In the purposed algorithm, a multicast node among current tree nodes is suitably assigned to each incoming user: Such a node is selected in a fashion that tree cost and the maximum end-to-end delay on the tree are jointly minimized. The existing and proposed algorithms are compared by experiments. In the simulation results, it is shown that the proposed algorithm approximately provides the cost saving of 30% and the delay saving of 10%, compared to the existing approaches. In conclusion, we see that the cost and delay aspects for multicast trees can be improved at the cost of additional computations.
Extraction of Passive Device Model Parameters Using Genetic Algorithms
Yun, Il-Gu ; Carastro, Lawrence A. ; Poddar, Ravi ; Brooke, Martin A. ; May, Gary S. ; Hyun, Kyung-Sook ; Pyun, Kwang-Eui ;
ETRI Journal, volume 22, issue 1, 2000, Pages 38~38
The extraction of model parameters for embedded passive components is crucial for designing and characterizing the performance of multichip module (MCM) substrates. In this paper, a method for optimizing the extraction of these parameters using genetic algorithms is presented. The results of this method are compared with optimization using the Levenberg-Marquardt (LM) algorithm used in the HSPICE circuit modeling tool. A set of integrated resistor structures are fabricated, and their scattering parameters are measured for a range of frequencies from 45 MHz to 5 GHz. Optimal equivalent circuit models for these structures are derived from the s-parameter measurements using each algorithm. Predicted s-parameters for the optimized equivalent circuit are then obtained from HSPICE. The difference between the measured and predicted s-parameters in the frequency range of interest is used as a measure of the accuracy of the two optimization algorithms. It is determined that the LM method is extremely dependent upon the initial starting point of the parameter search and is thus prone to become trapped in local minima. This drawback is alleviated and the accuracy of the parameter values obtained is improved using genetic algorithms.