• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.1
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• pp.69-82
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• 1993

본 논문에서는 디지틀 이동 통신 시스템의 열악한 페이딩 채널에 적합한 변복조 반식중의 하나인${\pi}$/4-shift QPSK 성능을 논하고, 그 성능 개선을 위한 새로운 TCM(trellis-coded modulation)을 적응하여 trellis-부호화된${\pi}$/8-shift 8SPSK 방식을 제안 한다. 기존의 ${\pi}$/4-shift QPSK변조 방식에 TCM의 도입은 요구된 대역폭과 송신 전력과 전송을 그대로 유지하면서 부호화와 변조를 일체화함으로서 부호화 이득(coding gain)을 얻을 수 있다. 이동 통신 채널에서 trellis-부호화된 ${\pi}$/8-shift 8PSK방식의 시스템 성능을 추정하기 위해서, 가산 백색 가우시안 잡음과 레일레이 페이딩 현상이 존재하는 채널에서, 차량속도 변화에 따른 도플러 효과에 의한 페이딩율이 10Hz와 30Hz인 두 경우에 대해 시스템을 모델링한다. Trellis-부호화된${\pi}$/8-shift 8PSK에 대한 부호화 이득은 비트 에러 확률을 적용하여 분석하고, 기본 시스템과 새롭게 모델링 되어진 시스템의 개선된 성능을 비교하기 위해, TCM의 상태수를 4,8,16으로 선정하여 비교 구현해 본 결과, 상태수가 커질수록 더 좋은 성능을 나타내고, 기존의 ${\pi}$/4-shift QPSK보다 trellis-부호된 ${\pi}$/8-shift 8PSK는 가산 백색 가우시안 잡음채널에서는 3~4dB의 부호화 이득을 얻고, 레일레이 페이티 채널하에서 3~16dB정도의 부호화 이득을 얻음을 알 수 있다.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.2
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• pp.104-112
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• 2007

We developed a $7{\times}7$ parallel multiplier using LTPS-TFT. The proposed multiplier has multi-valued logic 7-3 Compressor with folding, 3-2 Compressor, and final carry propagation adder. Architecture minimized the carry propagation. And power consumption reduced by switching the current source to the circuit which is operated in current mode. The proposed multiplier improved PDP by 23%, EDP by 59%, and propagation delay time by 47% compared with Wallace Tree multiplier.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.347-350
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• 2007

Adaptive arrays have been proposed as an effective means of mitigating Multiple Access Interference (MAI) and improving the performance of existing and future wireless communication systems. In this paper, we apply the analytical method proposed to analyse the theoretical Mean Bit Error Rate (BER) of an uncoded IS-95 based CDMA system with an array antenna at the BS in a Ricean fading environment. We present a modified expression for the Signal to Interference plus Noise (SINR) ratio as a function of the number of users, number of antennas and noise levels. We also verify the analytical results by means of simulations by considering different user and channel scenarios.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.10C
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• pp.1010-1018
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• 2007

In this paper, we propose a companding scheme to effectively reduce PAPR (Peak-to-Average Power Ratio) of the OFDM (Orthogonal frequency Division Multiplexing) signals. The proposed scheme is basically based on the companding scheme to consider both complexity and Bit Error Rate (BER) performance, and composed of the clipping followed by the companding scheme. In the first step of the proposed scheme, some of peak signals which do not influence the BER even without them, are clipped. In the second step, the proposed scheme utilizes the ${\mu}-law$ companding to effectively reduce the PAPR. Simulation results show that the proposed clipped companding scheme can provide more PAPR reduction without degradation of the BER performance, as compare to the conventional ${\mu}-law$ companding.

• Journal of the Korea Computer Industry Society
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• v.3 no.2
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• pp.149-158
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• 2002

This paper deals with design and verification of an arithmetic logic unit(ALU) to be used for development of optical computers. The ALU is based on optical switching device, $LiNbO_3$, which is easy to interface with electronic technology and most common in the market. It consists of an arithmetic/logic circuit performing logic operations, memory devices storing operands and the results of operations, and supplementary circuits to select instruction codes, and operates in bit-serial manner. In addition, a simulator is developed for verification of the design, and a set of basic instructions are executed in sequence and step-by-step changes in the accumulator and the memory are examined through simulations, to show that various operations are performed correctly.

• Journal of Broadcast Engineering
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• v.5 no.1
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• pp.31-40
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• 2000

In this paper, we propose an edge histogram to efficiently represent the edge distribution in the image for MPEG-7. To this end, we adopt global, semi-global, and local edge histogram bins. Also, we extract the edge information from the image in terms of image blocks rather than pixels, which reduces the extraction complexity and is also applicable to the block-based compression standards such as MPEG-1, and 2. Experimental results show that the proposed method yields better retrieval accuracy and feature extraction speed comparing to other non-homogeneous texture descriptors of MPEG-7 including the wavelet-based descriptor and local edge-based descriptor.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.681-684
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• 2015

Magnetization is very important in the ferro-magnetic physics and provides useful informations in the application field of magnetic devices. Generally, the only first acquired domain pattern is not helpful to recognize domain pattern. Many images are needed to visualize domain pattern through image processing. These images were obtained a 8-bit digital camera. The operation was the subtraction of pixel values of multi domain imanges from the images with 255 of pixel value, which was obtained in the saturated state of magnetic materials. The magnetic domain images was visualized gradually with increasing the number of subtracion operation. LABVIEW was used as an image processing tool and the optic microscope with a polarizer was used in this experiment.

• Journal of Mushroom
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• v.6 no.3_4
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• pp.126-130
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• 2008

The combination ratio of oyster mushroom cultivation supplements have used poplar sawdust(PS) 50% : beet pulp(BP) 30% : cotton seeds meal(CS) 20%. we substituted cotton seeds meal and beet pulp for food by-product dried wastes(DW) 10, 20. 30% respectively. In case of mixing with DW 10% except from BP, mycelial growth was inhibited a little, but mycelial density was accelerated. The more DW contents increase, the more mycelial growth was inhibited, but mycelial growth was accelerated a little, respectively. In case of mixing with DW except from CS, mycelial growth was similar to control almost. In case of mixing with DW except from CS and BP, mycelial growth was inhibited remarkably. CHUNCHU variety developed resistance to developed than SUHAN variety.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.335-338
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• 2005

Though GF(2) CA can only handle data with bit units, GF(2$^{p}$) CA can handle data with byte units. In this paper we analyze the state-transition of nongroup cellular automata(CA) with a single attractor over GF(2$^{p}$). And we propose the constructing method of the state-transition diagram of a linear SACA over GF(2$^{p}$) by using the concept of basic path. Also we propose the state-transition diagram of the nonlinear complemented SACA by using the state-transition diagram of a linear SACA.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.12C
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• pp.273-279
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• 2001

This paper describes a design and implementation of ISDN system on a chip which provides ISDN service and used to develop a low-price multimedia communication terminal. This ISDN SOC is an ISDN system control chip which has 32bit RISC processor, and it includes ISDN S interface transceiver, G.711 voice CODEC, PC interface for data communication, ISDN protocol which includes Q.931 call control protocol and internet protocol. It provides good solution to develope ISDN terminal equipment and ISDN terminal adaptor which connected with basic rate interface, because it minimize external peripheral devices.