• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.111.1-111.1
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• 2012

We examine the relationship between a type II radio burst that started from an unusually high frequency of 425 MHz (fundamental component) and an associated white-light coronal mass ejection on 2011 February 13. The radio burst had a drift rate of 2.5 MHz/sec, indicating a relatively high shock speed. From SDO AIA observations we find that a loop-like erupting front sweeps across high density coronal loops near the start time of the burst (17:34:15 UT). We find fragmented structures of the type II burst, which indicates the signature of the shock propagating through the multiple loops. The deduced distance of shock formation (0.06 Rs) from flare center and speed of the shock (1100 km $s^{-1}$) using the measured density from AIA/SDO observations are comparable to the height (0.05 Rs, from the solar surface) and speed (700 km $s^{-1}$) of the CME leading edge observed by STEREO/EUVI. We conclude that the type II burst could be onset even in the low corona (41 Mm or 0.06 Rs, above the solar surface) if a fast CME shock passes through the high density loops.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.109-112
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• 2000

The satellite communications are expected to play an important role to provide broadband multimedia services in the 21st century. According to this requirements, this paper describes the design and implementation of ATM-based high speed satellite modem ASIC chipset. The ASIC chip consists of three main parts, CODEC, Modulator and Demodulator. It supports burst and continuous mode operation with TDMA frame consisted of Reference bursts, Inbound burst, and Traffic burst. The maximum transmission rate is OC-3 (155Mbps) and the maximum operating clock speed is 220MHz. This ASIC chip was implemented with 0.25um CMOS technology.

• JSTS:Journal of Semiconductor Technology and Science
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• v.4 no.4
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• pp.275-279
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• 2004

A new burst mode clock and data recovery circuit is realized that improves the previousldy-known gated-oscilletor technique with half rate clock recovery, The circuit was fabricated with 0.25um CMOS technology, and its functions were confirmed up to 1 Gbps.

• Journal of Korea Multimedia Society
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• v.16 no.9
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• pp.1067-1076
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• 2013

Known as an important criterion that evaluates performance of future high-speed backbone networks, burst data loss ratio is well-studied in Optical Burst Switching networks. Current literatures mostly focus on reduce burst loss ratio without considering the system stability and link utilization after reducing. In this paper, we propose a novel framework which comes from feedback theoretic to dynamically control burst loss ratio in OBS. The proposed scheme tries to track the pre-set values of burst loss ratio and increases the stability and link utilization degree. The simulation results show that measured burst loss ratio always tracks setup reference with small errors, wavelength channel utilization is increased up to 2% and the system stability is also improved.

• The Transactions of the Korea Information Processing Society
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• v.7 no.6
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• pp.1923-1931
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• 2000

In this paper, e analyze the performance of the PSS-type Viterbi decoder which can reduce calculations and power consumption using the Monte Carlo simulations. Gaussian and burst noise channels are considered in this simulation, and we achieve that convolutional interleaver can reduce complexity and power consumption in burst noise channel. In order to implement the high-speed PSS-type Viterbi decoder, the architectures of decoder are presented, and we implemented the PSS-type Viterbi decoder for r=1/2, k=3 using the VHDL tool, and prove the decoding process.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.9A
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• pp.1359-1367
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• 2000

A new coherent detection scheme with data based channel estimation (DBCE) for CDMA/BP(staggered burst pilot in parallel) channel structure is proposed. Because the pilot burst initiates DBCE operation periodically it is shown to be remarkably stable to Gaussian noise and Doppler shift with proper parameter settings. In our own system parameter setting, there is a negligible loss(0.068 dB) in $E_{b}/N_{o}$ by the introduction of the burst pilot. When compared with an ideal coherent detection, the required $E_{b}/N_{o}$ on Doppler shift corresponding to the speed of 160Km/H is degraded less that 2.0 dB. the burst pilot can be implemented without complexity even though some extra correlators are needed for DBCE. This improvement is superior to the previously coherent CDMA detectors with external or internal pilot.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.10
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• pp.34-41
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• 1998

In this paper, we evaluate synchronization techniques suitable for high-speed ATM satellite communications with a transmission rate of 155Mbit/s, and propose optimal algorithms that improve the tracking performance, where QPSK is selected for a modulation scheme, and the receiver is operated in burst mode. Based on these asumptions, we proposed modified algorithms and architectures for automatic frequency control(AFC), carrier recovery(CR), and symbol timing recovery(STR) for burst acquisition. Analysis is performed under AWGN environments with respect to the number of required symbol, steady-state stability, and hardware implementation for the proposed algorithms.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.10
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• pp.27-33
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• 1998

In this paper, we designed a demodulator using proposed synchronization techniques and algorithms for high-speed ATM satellite burst modem, and analyzed various performance in the AWGN channel. In addition, as the preamble progressed, each synchronization process can be analyzed by using the mean and variance characteristics, and the convergence state and operation state using convergence probability can also be determined. In conclusion, we analyzed the Cell Loss Ratio(CLR) by integrating the burst acquisition with Unique Word(UW) detector performance, and verified that proposed TDMA receiver satisfied the generally required CLR performance adequately.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.4
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• pp.497-504
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• 2017

This paper proposes a method to measure the airburst height by utilizing a high speed camera. This method might be applied to the test of which flight target is alive after the burst. The proposed method consists of four main steps. The first step is to compute the impact point using the sea surface height. The second step is to compute the height of burst (HOB) by using the distance from the camera to the impact point. This could be different from the real explosion height. That is because the distance from the camera to the burst point is not the same as it from the camera to the impact point. Therefore, the third step is to calculate the approach angle of the flight target with respect to the installed camera. Then, the last step is to compensate the computed height by using the approach angle. The result of the proposed method is compared with it from the triangulation. In this paper, the HOB error is also analyzed regarding the approach angle difference. Based on this analysis, the camera position might be suggested for error reduction.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.365-368
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• 1995

Rotary Compressor has many AE(Acoustic Emission) sources according to condition of parts because it is operated with combination of various parts. In this study, analysis of AE raw signal generated form Rotary compressor which artificially-made parts inflicted abnormal condition was carried out. AE raw signals were acquired form high-speed A/D board, and many burst type signals were observed. By analyzing burst type signals which is caused form internal AE source,efficient AE parameters for monitoring and diagnosis were presented.