• Title/Summary/Keyword: Choi Chi-won

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Implementation of Mobile WiMAX Receiver using Mobile Computing Platform for SDR System (모바일 컴퓨팅 플랫폼을 이용한 SDR 기반 MOBILE WIMAX 수신기 구현)

  • Kim, Han Taek;Ahn, Chi Young;Kim, June;Choi, Seung Won
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.8 no.1
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    • pp.117-123
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    • 2012
  • This paper implements mobile Worldwide Interoperability for Microwave Access (WiMAX) receiver using Software Defined Radio (SDR) technology. SDR system is difficult to implement on the mobile handset because of restrictions that are computing power and under space constraints. The implemented receiver processes mobile WiMAX software modem on Open Multimedia Application Platform (OMAP) System on Chip (SoC) and Field Programmable Gate Array (FPGA). OMAP SoC is composed of ARM processor and Digital Signal Processor (DSP). ARM processor supports Single Instruction Multiple Data (SIMD) instruction which could operate on a vector of data with a single instruction and DSP is powerful image and video accelerators. For this reason, we suggest the possibility of SDR technology in the mobile handset. In order to verify the performance of the mobile WiMAX receiver, we measure the software modem runtime respectively. The experimental results show that the proposed receiver is able to do real-time signal processing.

Implementation of $2{\times}2$ MIMO LTE Base Station using GPU for SDR System (GPU를 이용한 SDR 시스템 용 LTE MIMO 기지국 기능 구현)

  • Lee, Seung Hak;Kim, Kyung Hoon;Ahn, Chi Young;Choi, Seung Won
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.8 no.4
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    • pp.91-98
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    • 2012
  • This paper implements 2X2 MIMO Long Term Evolution (LTE) base station using Software defined radio (SDR) technology. The implemented base station system processes baseband signals on a Graphics Processor Unit(GPU). GPU is a high-speed parallel processor which provides very important advantage of using a very powerful C-based programming environment that is Compute Unified Device Architecture (CUDA). The implemented software-based base station system processes baseband signals through GPU. It utilizes USRP2 as its RF transceiver. In order to guarantee a real-time processing of LTE baseband signals, we have adopted well-known signal processing algorithms such as frame synchronization algorithms, ML detection, etc. using GPU operating in parallel processing.

Effect on Body Balance due to mouth guard (마우스 가드가 신체 균형에 미치는 영향)

  • Won, Hyeon-Jin;Kim, Chi-Young;Choi, Sung-Min
    • Journal of Technologic Dentistry
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    • v.37 no.2
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    • pp.63-67
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    • 2015
  • Purpose: This study, it was observed on the effect of material and thickness of the mouth guard on postural balance in order to assess the influence of the use of a mouth guard. Methods: The mouth guards of 10 adults selected as the experiment subject was sorted into each of hard and soft material, and these were made as thickness of 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm by each of the material. Results: The results of this study are expected to wear the mouthguard hard to influence positive influence on the improvement of the muscle strength, static balance. Conclusion: Suggest the need for additional research on dynamic balance.

Development of Micro Metal Forming Manufacturing System (초미세 마이크로 소성성형 가공시스템 기술 개발)

  • Lee Nak-Kyu;Choi Tae-Hoon;Lee Hye-Jin;Chi Seog-Ou;Park Hoon-Jae;La Won-Ki
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2005.05a
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    • pp.383-388
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    • 2005
  • In this paper Research development about a micro metal forming manufacturing system has been developed. A micro forming system has been achieved in Japan and it's developed micro press is limited to single forming process. To coincide with the purpose to be more practical, research and development is necessary about the press which the multi forming process is possible. We set the development of the equipment including micro deep drawing, micro punching and micro restriking process to the goal. To achieve this goal, Research about micro forming process to be related to multi process forming must be preceded first. Material selection and analysis about micro forming process are accomplished in this paper. And the basis research to make actual system is accomplished.

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MOBILE WIMAX 기반 향상된 다중 안테나 시스템의 고정소수점 설계

  • Kim, Hak-Min;Ahn, Chi-Young;Yun, Yu-Suk;Jung, Jae-Ho;Choi, Seung-Won
    • 한국정보통신설비학회:학술대회논문집
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    • 2008.08a
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    • pp.409-413
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    • 2008
  • In this paper, we introduce a platform of advanced multiple antenna system based on orthogonal frequency-division multiplexing (OFDM). The advanced multiple antennas have beamforming gain using array antenna. In array antenna systems, received signal has phase delay caused distance of each antennas, therefore it should compensate with optimum weight vector which calculated by Lagrange algorithm. To implement the presented above procedures using Digital Signal Processor (DSP), we should fixed-point design. The performance of implemented platform is verified through MATLAB$^{(R)}$ simulations with various signal environments.

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