• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1983.10a
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• pp.77-80
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• 1983

90Mbps 디지털 비데오 코덱의 구성방법으로 서pel 당 비트수, sampling 주파수, 데이터 감축 방법등의 여러가지 설계 요건들이 SQNR, 하아드웨어 복잡성 정도에 따라 비교검토 되었으며 그 결과 HBL control을 포함하는 9bit PCM codec 방식이 90Mbps 전송속도에서 타당함이 밝혀졌다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.462-466
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• 2002

This paper describes a low frequency electrical nerve stimulator for muscle care. The developed system consist of 8bit low power consumed MPU, voltage boosting circuit converting 9V input to 120V output, repairing circuit for distorted output pulse, LED and buttons for I/O, and electro-chemical pad. The pulse generation algorithm for the muscle care effect is developed with basic pulses such as a single phase rectangle pulse, symmetric rectangle pulse, and depolarized interrupt pulse.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.9
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• pp.1667-1671
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• 2015

Multi-level holographic data storage is a candidate for the next generation data storage system, since it can store more than one bit per pixel. It is possible to increase the number of codewords if the number of levels is increased, and the code with an appropriate selection of codewords can also increase the minimum distance. In this paper, we propose three multi-level modulation codes of the code rate 1 bit/pixel and compare the performance according to the minimum distance. The result shows that the code with small number of levels is better than that of large number of levels because it is hard to detect threshold value.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.9 no.1
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• pp.1-10
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• 1984

The time division multiplexing PCM encoder which is constructed for an airborne telemetering system is investigated. Selected by program switch, the PCM encoder has 0~64 words/framd($\pm$5V full scale) of allowable analog input channels, 0~30bits(5V$\pm$1V or 0V$\pm$1V dc) of discrete channels, 70 and 140K bits/sec of bit rate and 8~12bits/word of resolution. And filtered output PCM code is NRZ-L and Bi-S through the 5 pole Bessel LPF(f=100kHz), and the maximum accuracy of PCM encoder is $\pm$0.2% of its full scale.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.9
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• pp.491-496
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• 2014

We derive an analytical expression for the bit-error rate (ber) of optimal single user detection (osud) of a binary phase-shift keying (bpsk) signal corrupted by a gaussian cochannel interferer (cci). the channel capacity is also calculated to investigate the ber performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.9
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• pp.1672-1677
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• 2015

The multi-level holographic storage system can store more than one bit per pixel. In this paper, we introduce a 6-pixel 4-level modulation code and compare with 4-level 6/9 modulation code and 2/3 modulation code. The proposed 6-pixel modulation code has the minimum Euclidean distance 3. The 6-pixel modulation code is approximately 1dB better than the other modulation codes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.3
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• pp.348-354
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• 1993

In this research, a multi-tree coder at 9.6Kbits/sec using a novel scheme for adaptation of the short-term coefficients is developed. The overall delay of the tree coder is maintained at 2.5 msec(16 samples at the 6.4KHz sampling frequency). This coder produces good quality speech over ideal channels, and it is very robust to channel errors up to a bit error rate (BER) of $10^{-3}$. This robustness is achieved by using a parallel adaptation scheme in combination with the use of a smoothed version of the received excitation sequence for adaptation of the short-term prediction coefficients. For the multi-tree coder, reconstructed output speech is evaluated using signal-to-quantization noise ratios (SNR), segmental SNRs, and informal listening tests.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.9B
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• pp.1209-1214
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• 2001

본 논문에서는 양방향 디지털 가입자 회선 (Digital Subscriber Lines) 통신을 위해 격자 구조 (lattice structure)와 직교화된 IIR 형태의 필터가 결합된, 이른바 CALAOI(CAscade of LAttice and Orthogonalized IIR) 구조를 갖는 새로운 반향제거기를 제안한다. 모의실험을 통하여 CALAOI 반향제거기는 기존의 FIR 및 IIR 반향제거기보다 훨씬 적은 계산량 및 메모리, 그리고 빠른 수렴속도를 갖는 안정적인 반향제거기임을 확인할 수 있었다. CALAOI 반향 제거기는 xDSL뿐만 아니라, GIGA-bit Ethernet 등 고속 양방향 통신에서 서비스의 성능을 극대화하는데 크게 기여할 것으로 예상된다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.5
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• pp.2272-2278
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• 2011

It is essential to various evaluate about statistic character of the signal and additional noise for optimization of the optical communication system. We expressed various error probability with the m which was bandwidth and a bit numerical function and carried out performance evaluation of a PIN receiver. This research analyzed the receiving sensitivity of the PIN receiver and verified reception sensitivity through computer simulation in the optical communication system. As a result, the receiving sensitivity for PIN receiver are $9.2{\times}10^4$ photon/bit for given error probability.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.6
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• pp.1182-1188
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• 2005

In this paper, various power delay profiles (PDP) are simulated to study the influence of the PDP shape on the bit error rate (BER) performance of Orthogonal Frequency Division Multiplexing (OFDM) communication systems. Assuming Rayleigh fading with 16-QAM modulation scheme, the simulation focuses on the investigation of the various shapes of the PDP which are often characterized by peaks, slope, attenuation and distance of an echo profile of waves. This yields information about the properties of the channel, and can be applied to decide the performance of the systems according to the channel.