• 전자공학회논문지A
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• 제33A권7호
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• pp.23-33
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• 1996

This paper deals with the design of a recursively-indexed binary code for facsimile soruces and its performance. Sources used here are run-lengths of white pixels form higher-resolution facsimile. The modified huffman code used for G.3 facsimile is chosen for the performance comparison. Experiments confirm the fact that recursive indexing preserves the entropy of a memoryless geometric source: the entropy of recursively-indexed physical surce iwth roughly geometric distributin remains within 2% of the empirical source entropy. The designed recursively-indexed binary codes consist of a code applied to text-type documents and to graphics - type documents is compared iwth that of the modified huffman code. Numerical resutls show that the modified huffman code performs well for text-type documents and not equally well for graphics-tyep documents. On the other hand, recursively-indexed binary codes have shown a better performance for graphics-type documents whose distribution are similar to a geometric distribution. Specifically, the code rates of recursively-indexed binary codes with 60 codewords are from 8% to 20% of the empirical source entropy smaller than that of th emodified huffman code with 91 codewords.

• Journal of Communications and Networks
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• 제7권3호
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• pp.258-262
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• 2005

An adaptive beamforming system based on code filtering and differential correlation approaches is proposed. The differential correlation method was originally proposed for time delay estimation of direct sequence code division multiple access (DS-CDMA) systems under near-far ratio conditions and the code filtering correlation algorithm, on the other hand, was proposed for array response estimation in DS-CDMA systems under perfect power control. In this paper, by combining differential correlation concept with the code filtering beamforming technology, an accurate estimate of the beam forming weights and an enhanced performance of DS-CDMA systems under sever near-far ratio conditions is achieved. The system performance in terms of beam pattern and bit-error-rate (HER) shows that the proposed adaptive beamformer outperforms the conventional code filtering correlation technique.

• 대한전자공학회논문지
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• 제25권1호
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• pp.108-114
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• 1988

We have developed a program that minimizes the chip area with effective code assignment of microinstructions when the control part of VLSI system is implemented in the PLA. While conventional algorithms are composed of one pass, the algorithm proposed in this paper is composed of two passes and it consists of three principal procedures: a procedure for the determination of the code assignment order, a procedure for the code assignment and a procedure for the reduction of the code length. especially, we have proposed a new method of folding back for the reduction of the code length. We have obtained the result of 4 bit code length and 9 product terms when 11 micro-instructions and 6 microoperations were given as a inputs. Therefore, we have certified that it could be used efficiently for the control part of the processors.

• 대한전자공학회논문지
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• 제20권5호
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• pp.23-30
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• 1983

Duobinary 선로부호를 수정하여 "0"의 길이가 제한된 최소 대역폭 선로부호를 설계하였다. 이 새로운 부호는 duobinary와는 달리 "0"기 길이가 제한되어 self-clocking 특성을 가지므로, 수신측의 원활한 동기 재생을 위한 송신측의 데이타 스크램블링이 필요없다. 또한, 눈폭(eye width)과 오판율(error rate) 특성도 duobinary에 버금하며, 전력스펙트럼도 그에 유사하여, optical fiber와 같은 저역통파특성의 선로에 적합하다.

• 한국전산유체공학회지
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• 제21권3호
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• pp.89-97
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• 2016

In this study, direct code coupling, in which two codes share a single flow field, was conducted using 3-dimensional high resolution thermal hydraulics code, CUPID and 1-dimensional system analysis code, MARS. This approach provide the merit to use versatile capability of MARS for nuclear power plants and 3-dimensional T/H analysis capability of CUPID. Numerical Method to directly couple CUPID and MARS was described in this paper. The straight flow and manometer flow oscillation were calculated to verify conservation of coupled CUPID/MARS code in mass, momentum, and energy. This verification calculations indicates that the CUPID/MARS is coupled appropriately in numerical aspect and the coupled code can be applied to nuclear reactor thermal hydraulics after validation against integral transient experiments.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권7호
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• pp.3156-3167
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• 2020

One drawback of polar codes is that they are not universal, that is, to achieve optimal performance, different polar codes are required for different kinds of channel. This paper proposes a polar code construction scheme for Nakagami-m fading channel. The scheme fully considers the characteristics of Nakagami-m fading channel, and uses the optimized Bhattacharyya parameter bounds. The constructed code is applied to an orthogonal frequency division multiplexing (OFDM) system over Nakagami-m fading channel to prove the performance of polar code. Simulation result shows the proposed codes can get excellent bit error rate (BER) performance with successive cancellation list (SCL) decoding. For example, the designed polar code with cyclic redundancy check (CRC) aided SCL (L = 8) decoding achieves 1.1dB of gain over LDPC at average BER about 10^-5 under 4-quadrature amplitude modulation (4QAM) while the code length is 1024, rate is 0.5.

• Nuclear Engineering and Technology
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• 제45권5호
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• pp.665-674
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• 2013

This paper presents the development and validation methods of the FUTURE (FUel cycle analysis Tool for nUcleaR Energy) code, which was developed for a dynamic material flow evaluation and economic analysis of the nuclear fuel cycle. This code enables an evaluation of a nuclear material flow and its economy for diverse nuclear fuel cycles based on a predictable scenario. The most notable virtue of this FUTURE code, which was developed using C# and MICROSOFT SQL DBMS, is that a program user can design a nuclear fuel cycle process easily using a standard process on the canvas screen through a drag-and-drop method. From the user's point of view, this code is very easy to use thanks to its high flexibility. In addition, the new code also enables the maintenance of data integrity by constructing a database environment of the results of the nuclear fuel cycle analyses.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2016년도 추계학술대회
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• pp.317-320
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• 2016

임베디드 시스템에서 타 업체의 요청으로 코드를 공개해야 되면 하드웨어 복사 방지 대책을 세워야 힘들게 개발한 제품을 지킬 수 있다. 보안 IC칩을 사용하지 않고, 핵심코드와 하드웨어 복사를 방지하면서 펌웨어 코드를 공개할 수 있는 보안 플랫폼을 제안하고자 한다. Cortex-M3기반 MCU의 내부 Flash의 영역을 IAP(In-application programming)와 APP(Application)으로 나누어, IAP영역에는 핵심코드와 보안인증 코드를 배치하고, APP에서는 타업체의 개발자가 공개된 핵심코드의 Prototype을 사용하여 구현한 Application이 배치되는 플랫폼을 제안한다.

• 한국통신학회논문지
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• 제22권6호
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• pp.1302-1310
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• 1997

In this paper, we propose a dynamic code allocation strategy using voice activity detection and evaluate the performance of a dynamic code allocation strategy using voice activeity detection in DS-CDMA system. Proposed method allocates code to mobile terminal according to the residual capacity computed by SIR in the base station. In hot spot traffic loading cell, we find that the performance of proposed method is better than that of a fixed code assignment strategy using voice activity detection. Also, we find that the proposed method provide much improvement in blocking probability against the dynamic code assignment strategy withoug voice activity detection.

• 한국통신학회논문지
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• 제26권10B호
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• pp.1444-1452
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• 2001

얼굴인식에서 정보 이론적 접근방법은 얼굴 영상을 기저 영상의 합으로 분해하는 것을 기초로 한다. 가장 많이 쓰이고 있는 방법은 Principal Component Analysis (PCA)를 기반으로 하는 eigenface 방법이다. PCA를 기반으로 하는 방법은 데이터의 2차 통계적 구조만을 고려하므로 화소 사이의 고차 통계적 의존성은 고려되지 않는다. Factorial code 표현법은 효과적인 정보 표현의 좋은 방법으로 알려져 있고 이것은 Independent Component Analysis (ICA)와 밀접한 관련이 있다. Factorial code 표현법은 eigenface 방법과 비교할 때 중요한 정보가 포함되어 있는 데이터의 고차 통계적 구조도 고려되어 더욱 효과적인 정보 표현을 기대할 수 있다. 이 논문에서는 PCA를 이용하여 찾아낸 저차원 특징 공간에서 Factorial code 표현법을 이용하여 얼굴인식을 위한 통계적 특징점을 찾아낸다. 얼굴 인식에 있어서 Factorial code 표현법이 eigenface 방법보다 성능이 우수함을 모의실험을 통하여 입증한다.