• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.16 no.11
• /
• pp.1054-1062
• /
• 1991

In this paper a communication system using direct sequence spread spectrum (DS/SS) technique is constructed to transmit burst format data over power line channel with impulsive noise and narrowband interferences. Fast code synchronization is acquired by digital matched filter and data decision is accomplished by sampling pulses. In order to examine the performance of the power line communication system, but error rate and packet loss rate are measured over the simulation channel with various noise sources. When the packet composed of 1-bit preamble and 63-bit data is transmitted under very high burst impulsive noise, the bit error rate is about 10$^3$-10$^4$ and the packet loss rate is below 0.07.

• Journal of Advanced Navigation Technology
• /
• v.13 no.3
• /
• pp.337-343
• /
• 2009

In this paper, we proposed a burst mode symbol timing recovery unit that is applicable to the VDL Mode-2 using D8PSK modulation. A method that IIR loop filter is used to minimize symbol timing error is hard to apply to burst mode because its convergence time is long. That is, the fast convergence property is important. In this paper, the proposed method takes one sample which has maximum symbol power after the initial synchronization has been achieved by using preambles. The main principle of operation is that the unit moves one sample clock to advance or retard according to symbol power. We verify that the proposed method is operated well in ${\pm}100$ ppm or greater through the test results between Australia ADS Corp. transmitter and the designed receiver.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.20 no.4
• /
• pp.497-504
• /
• 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 KIEE Conference
• /
• 1988.07a
• /
• pp.198-202
• /
• 1988

In digital mobile communications received speech data are affected by burst errors as well as random errors. To overcome these errors we propose a bit-selective forward error correction scheme for the speech data which is sub-band coded at 13 kbps and transmitted over a 16 kbps channel. For a few error correcting codes the signal-to-noise ratio of error-corrected speech is obtained and compared through the simulation of mobile communication channels.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.10 no.3
• /
• pp.147-152
• /
• 1985

The error-trapping decoder is constructed for the (7, 3) Reed-Solomon code. The syndrome resister is constructed with the encoder and the substanial test logic circuits. The element of GF(8) is represented by the triple D-flip-floops. The hardware is constructed. And it is controlled by the micro computer(Apple II). The time for the encoding and the decoding were $350\musecs and 910u secs respectively. The experimental results show that the two symbol errors were corrected and 4-bit-binary-burst errors were also corrected.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.7 no.3
• /
• pp.185-191
• /
• 2005

An accurate prediction of dormancy release and bud burst in temperate zone fruit trees is indispensable for farmers to plan heating time under partially controlled environments as well as to reduce the risk of frost damage in open fields. A thermal time-based two-step phenological model that originated in Italy was applied to two important grapevine cultivars in Korea for predicting bud-burst dates. The model consists of two sequential periods: a rest period described by chilling requirement and a forcing period described by heating requirement. It requires daily maximum and minimum temperature as an input and calculates daily chill units (chill days in negative sign) until a pre-determined chilling requirement for rest release is met. After the projected rest release date, it adds daily heat units (anti-chill days in positive sign) to the chilling requirement. The date when the sum reaches zero isregarded as the bud-burst in the model. Controlled environment experiments using field sampled twigs of 'Campbell Early' and 'Kyoho' cultivars were carried out in the vineyard at the National Horticultural Research Institute (NHRI) in Suwon during 2004-2005 to derive the model parameters: threshold temperature for chilling and chilling requirement for breaking dormancy. The model adjusted with the selected parameters was applied to the 1994-2004 daily temperature data obtained from the automated weather station in the NHRI vineyard to estimate bud burst dates of two cultivars and the results were compared with the observed data. The model showed a consistently good performance in predicting the bud burst of 'Campbell Early' and 'Kyoho' cultivars with 2.6 and 2.5 days of root mean squared error, respectively.

• Proceedings of the Optical Society of Korea Conference
• /
• 2003.02a
• /
• pp.72-73
• /
• 2003

In volume holographic memory (VHM), two-dimensional data array (i.e. data page) is used for the recording and the retrieving process with the aid of spatial light modulator (SLM) and CCD camera. Due to this two-dimensional parallel data processing, burst errors in this system also have two-dimensional characteristics in a data page domain. In this paper, we present a channel model of the burst noise and burst error for the VHM system using disk type recording media. (omitted)

• Journal of the Korean Institute of Telematics and Electronics B
• /
• v.33B no.6
• /
• pp.119-127
• /
• 1996

The proposed method uses a signal of the smae frequency as the input modulating carrier frequency and of a different phase. This signal is generated in the digital automatic frequency control part to decide the input color demodulated signal. And the phase error from the burst signal is calculated. The calculated phase error is utilized to rmove the phase error contained inthe demodulated color signal. In this paper, digital signal processing of automatic color control is proposed for VCR system campatible with both NTSC and PAL TV systems.

• ETRI Journal
• /
• v.35 no.6
• /
• pp.1068-1074
• /
• 2013

This paper proposes an additional forward error correction (FEC) layer to compensate for the defectiveness inherent in the conventional FEC layer in the Long Term Evolution specifications. The proposed additional layer is called a graceful degradation (GD)-FEC layer and maintains desirable service quality even under burst data loss conditions of a few seconds. This paper also proposes a non-delayed decoding (NDD)-GD-FEC layer that is inherent in the decoding process. Computer simulations and device-based tests show a better loss recovery performance with a negligible increase in CPU utilization and occupied memory size.

• The Magazine of the IEIE
• /
• v.11 no.2
• /
• pp.1-11
• /
• 1984

본 지 2월호에서 구술한 선형부호에 이어 이번호에서는 순회부호에 대해 기술하고자 한다. 선형블럭부호중 중요한 부류에 속하는 순회부호(cyclic code)는 그 내용이 대수적 구조를 갖고 있어 부호화 회로는 물론 부호에 필요한 오증(syndrome)계산회로 등 귀환연결이 있는 치환레지스터(shift register)를 사용한 장치화(implementation)가 매우 용이하다는 이점이 있다. 이런 순회부호는 산발오진(random error)뿐 아니라 연집오진(burst error)도 정정할 수 있는 매우 효과적인 부호로서 다중오진정정능력(multiple error correcting capability)을 갖는 BCH부호도 순회부호의 일종이다.