• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.8
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• pp.12-17
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• 2009

We have implement어 a bust mode optical transmitter using digital temperature compensation architecture with a microprocessor. Instead of previous analog real time technique, we used digital sampling and holding technique for the temperature compensation in order to get stable high speed data transmission of the laser diode. This digital temperature compensation technique should be complemented the previous analog method with accuracy and effectiveness in the over Gb/s transmitting application.

• The Journal of the Acoustical Society of Korea
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• v.17 no.5
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• pp.63-68
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• 1998

광대역 정보통신망(B-ISDN)에 적합한 직접 제공법의 스트리밍모드 비연결형 서버 는 단일 셀의 전송시간 동안 셀의 송·수신 및 룩업(lookup)을 수행해야 한다는 시간적인 제약을 받기 때문에 버스트 트래픽(Burst Traffic)이 발생했을 경우 셀 손실이 많다는 단점 을 가지고 있다. 따라서 본 논문에서는 ATM 망의 스트리밍 모드 비연결형 서버가 고속으 로 데이터를 처리하여 셀 손실을 줄일 수 있도록 하기 위해 DBLCAM을 제안하였으며, 입 력 VPI(Virtual Path Identifier)/VCI(Virtual Channel Identifier)에 대한 연결 번호를 출력하 는 기능의 포워딩 테이블 VPC맵을 제안된 DBLCAM과 이중 포트 SRAM을 이용하여 설계 하였다.

• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.245-248
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• 2001

본 논문에서는 연집 오류(burst error)에 우수한 정정 능력을 보이는 고속 RS(Reed-Solomon) 복호기를 제안한다. 제안된 RS 복호기는 RS(n, k, t); (37 < n ≤ 255, 21 < k ≤ 239, t = 8)의 사양을 지원하며 수정 유클리드 알고리즘(modified Euclid´s algorithm)을 이용한 시스톨릭 어레이(systolic array) 방식의 병렬처리 구조로 설계되었다. 고속 RS 복호기의 효율적인 VSLI 설계를 위하여 새로운 방식의 수정 유클리드 알고리즘 연간 회로를 제안한다. 제안된 수정 유클리드 알고리즘 회로는 2t + 1의 연산 지연 시간을 갖으며 기존 구조의 연산 지연 시간인 3t + 37에 비하여 t = 8 인 경우 약 72%의 연산 지연이 감소하였다. 제안된 구조를 VHDL을 이용하여 설계하였으며 SAMSUNG 0.5㎛(KG80) 라이브러리를 이용하여 논리 합성과 타이밍 검증을 수행하였다. 합성된 RS 복호기의 총 게이트 수는 약 77,000 개이며 최대 80MHz의 동작 속도를 나타내었다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.05a
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• pp.243-247
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• 1999

For the purpose of LAN or data transmission line design with high speed and reliability using power lines, in this paper, we present CSK/SS-DS signal transmission characteristics simulations with changing channel characteristics due to impedance fluctuation. And we also simulated the signal transmissions with a strong impulsive burst noise and with a gaussian random noise. We introduce a simple channel equalization filtering method that solves the synchronization problem of CSK/SS-DS with fluctuating channel characteristics or low S/N ratio.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.854-858
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• 1987

This paper considers impulsive noise which produce burst error in high speed(approx.160Kbps) data transmission like ISDN(Integrated Servise Digital Network) using PSTN(Public Switching Telephone Network). To begin with, we obtains the transfer function of subscriber line to calculate the variation of bandwidth when the gain of receiver is fixed and channel capacity of non-gaussian channel in upper-and lower bound, and evaluates the transmission capability. In this paper compares channel capacity bounds which obtains when probability density function of impulsive noise is Laplacian distribution function with impulsive noise generated by waveform synthesier.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.3
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• pp.9-18
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• 1998

For constructionof the next generation satellite B-ISDN/ATM networks considering integration with terrestrial information infrastructure networks, various high speed and wideband satellites with be launched and they will make used of frequency reue techniques for efficient management of limited frequency resource. Therefore, CCI(Co-Channel Interference) inherent in frequency reuse will be a dominant factor in performance degradation of satellite networks. This paper alanyzes the ATM cell transmission performance degradation caused by CCI. The satellite link, including up-link and down-link thermal noise, CCI, and nonlinear satellite transponder, is modeled and interleaving technique is used for compensating the ATM cell transmission performance degradation caused by burst error of satellite link. First, each satellite link subsystem is analyzed in detail and then end-to-end ATM cell transmission performance is evaluated with BER and CLR. Specifically, ATMcell transmission performance degradation caused by CCI is evaluated in detail.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.11
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• pp.19-31
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• 1996

Spread spectrum method gurantees good performance in digital communication system under multi-path interference and jamming signals. The purpose of this paper is to develop the wireless modem using DS/SS techinque. The transceiver consists of a spread spectrum DQPSK transmitter and a mtching receiver. The system operates with the chipping rate set to 4 Mcps and the number of chips/symbol at 64, making the data rate 62.5 Kbps using QPSK modilation. The receiver section uses a digital matched filter for fast acquisition of burst signals and uses the comparing the BER of proposed system iwth that of narrow bnd system under various additive white gaussian noises. It is showen that the proposed sysem has better performance than narrow band system. When jamming signals is added to the suggested DS/SS system, we also show that the experimental performance (BER) of the suggested wireless modem is almost same as theroretical performance.

• 한국연소학회:학술대회논문집
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• 2012.04a
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• pp.245-246
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• 2012

The possibility that self-ignition can be generated near an obstacle is high in practical applications such as a hydrogen car. In this paper, experimental investigations were suggested to understand the effects of a wall on self-ignition phenomena through high-speed images. The results showed that the existence of a wall could not change the ignition phenomena itself irrespective of wall height and burst pressure. However, when a strong flame was induced in the tube, a wall could promote the flame stabilization.

• Proceedings of the KAIS Fall Conference
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• 2004.11a
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• pp.206-209
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• 2004

Pentium4의 가장 큰 특징은 병렬처리의 최적화이다. 인텔사의 최신 마이크로 프로세서 Pentium4에 적용된 기술들은 SSE2, Intel NetBurst Micro-Architecture, Hyper-Threading Technology 등이다. CPU 속도의 향상 기법은 크게 클럭 속도의 증가, IPC의 증가, 파이프 라이닝의 길이를 길게 하고, 트랜지스터 집적도를 높이는 것 등이다. 인텔이 Pentium4에 적용한 기술들은 구조론적인 관점에 입각해서 원칙을 잘 지켰다고 할 수 있다. 메모리 차원에서의 속도 향상 기법은 보다 큰 메모리를 사용하고, 넓은 데이터 전송 대역폭을 가지게 하고, 그리고 전송속도를 빠르게 하는 방법이 있다. 각 방법은 물리학적인 법칙에서 빛의 속도 보다 빨라 질 수 없다. 그러므로 속도 증가에는 한계가 있다. 이것을 최소화하기 위한 방책으로는 멀티프로세서와 분산처리로 다소 얼마간의 속도 차를 해결할 수 있을 것이다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.12C
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• pp.1633-1641
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• 2004

In satellite digital broadcasting and satellite internet, severe burst errors occur in the high-speed return channel from the satellite to mobiles. In this paper, we analyze the performance of the forward error correction (FEC) coding method in the Rayleigh fading return channel. We first investigate the channel model of Loo, LutB, Vucetic and Corazza. We then compare the performance of the convolutional, Reed-Solomon (RS), convolution-RS concatenation, and Turbo codes in rayleigh fading channel.