• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.10B
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• pp.1216-1221
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• 2011

We propose a multiplexed fiber Bragg grating (FBG) sensor network for vessel monitoring to measure the variation of strain and temperature by environmental perturbation based on code division multiple access (CDMA). The center wavelength of FBG was linearly changed by environmental perturbation such as strain and temperature variation so that we could be monitoring the state of sensors. A RSOA was used as optical broadband source and which was modulated by using pseudo random binary sequence (PRBS) signal. The correlation peak of reflected signal from sensor networks was measured. In this paper, we used the sliding correlation techniques for high speed response and dynamic rage of sensors.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.3 no.2
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• pp.22-29
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• 1992

In recent years there has been increased interest in a class of multiple-access techniques known as code division multiple-access(CDMA). As the trend for ever increasing data transmission rate and high error performance continues while conserving bandwidth, the needs arise for good highrate R=b/v convolu- tional codes such as punctured codes. In this paper, the packet error propability has been analyzed in code division multiple-access packet radio system which utilize punctured convolutional code and hard-decision Viterbi decoding.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04b
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• pp.652-654
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• 2002

본 연구에서는 물체의 길이론 측정하기 위한 영상 처리 방법으로 하나의 이미지 프레임으로는 처리하기 힘든 큰 물체를 두 개의 프레임으로 분할하여 처리함으로써 정밀한 측정을 할 수 있는 길이 측정 기법을 제안한다. 본 연구에서 제안한 분할 측정 방식은 이진수로 인코딩되어 있는 눈금 코드 블록을 이용하여 그 차이를 계산하여 상대적으로 측정되어 물체의 크기에 상관없이 정확한 측정이 가능한 방식으로, 공장자동화 시스템의 제품 검사 공정에 효과적으로 사용됨을 보인다.

• Journal of the Korea Society of Computer and Information
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• v.3 no.3
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• pp.121-127
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• 1998

In this paper, using diversity and convolution code in the DS/CDMA system, have been the performance analized. In this modulation shceme is using QPSK. Channel to CDMA system has been approximated by Rayleight fading channel considering effect for multi-path. In this assumed that receiver is WTDL(Wide-band Tappped Delay Line) receiver, and in this condition, average error probability of DS/CDMA.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.179-180
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• 2008

배전선로의 효과적인 운영을 위해 최근 들어 자동검침 데이터를 활용한 부하분석에 대한 연구가 진행되고 있다. 일반적인 부하분석 방식은 자동검침 고객의 데이터를 이용하여 대표 부하패턴을 생성하고 이를 이용하여 미 검침 고객의 부하패턴을 생성하여, 전체 배전선로의 회선 및 구간에 대한 15분/시간/일/주/월 단위의 최대부하 및 부하패턴 등을 분석하는 방법이다. 기존에는 고객을 분류하기 위해 계약종별 코드만을 사용하였으나, 같은 계약종별 코드를 갖는 고객이라 하더라도 부하패턴이 다른 경우가 많아서 부하분석의 정확도를 떨어뜨렸다. 본 연구에서는 고객의 계약종별 코드뿐 아니라 다양한 고객속성 정보와 15분 단위 자동검침 데이터를 이용하여 k-means 기법을 통해 고객을 분류하는 방식을 제안하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.8C
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• pp.1069-1075
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• 2004

In this paper, we show the equivalence between complementary code keying (CCK) codeword and coset of the first order Reed-Muller (RM) code with variables of three. The CCK codewords are Golay sequences which have peak-to-average power ratio (PAPR) of two at most and can correct one error. We propose a CCK-orthogonal frequency division multiplexing (OFDM) modem to reduce PAPR. Also, we present the performance improvement techniques by increasing the variables of four to correct three errors and reduce PAPR at least 9㏈ with this system. Although, two Fast Hadamard Transform (FHT) blocks of size 8 64 are required at the receiver, we reduce the complexity by using FHT blocks of size 8 64 and 2 4 without deteriorating the performance. We generalize our results that we may increase the variables of RM code to enhance the error correcting and PAPR reduction capabilities without increasing receiver's complexity.

• Journal of Digital Convergence
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• v.14 no.3
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• pp.235-241
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• 2016

Among recent issues emerging in the areas related to the society, health has received the most attention. In this paper, for a patient unable to do self-care because of worsened diseases, a biological information transfer method is proposed by which the disease information can be securely managed, by attaching an implantable device into the body. Our method object of the invention is to prevent a third party from illegally intercepting and interfering with the biological information attached to the insertion device in the body. In the proposed technique to improve the safety of the patient between the hospital and physician by assigning each code to the biometric information of the patient in order to prevent a third party tapping and interfering. In addition, our method is assigned a code necessary for encoding in advance to confirm the biological information between the patient and the hospital (doctor) in a manner dividing the bio-information code. In particular, the proposed technique makes a third party unable to illegally tap or interfere in, by previously generating a code used for encoding so that it can be stored in the database of the hospital, which not only decreased hospital care time to 6.9%, but also increased work efficiency rate up to 12.7%.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12B
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• pp.2342-2348
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• 1999

DCT-based codebook design using binary tree was proposed to reduce computation time and to solve the initial codebook problem. In this method, DCT coefficient of training vectors that has maximum variance is to be a split key and the mean of coefficients at the location is used as split threshold, then balanced binary tree for final codebook is formed. However edge degradation appears in the reconstructed image, since the blocks of shade region are frequently selected for codevector. In this paper, we propose DCT-based vector quantization codebook design using unbalanced binary tree. Above all, the node that has the largest split key is splited. So the number of edge codevector can be increased. From the simulation results, this method reconstructs the edge region sincerely and shows higher PSNR than previous methods.

• Journal of KIISE:Computer Systems and Theory
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• v.28 no.5
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• pp.245-258
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• 2001

VLIW에서는 프로그램 코드를 병렬화 하는 작업이 모두 컴파일러에 의해서만 이루어진다. 따라서 병렬로 수행될 연산어들을 명시적으로 나타내 주어야 하며, 이를 위한 명령어 인코딩 방식으로 전개 인코딩 방식과 압축 인코딩 방식이 사용되어 왔다. 각 인코딩 방식들은 명령어의 적재 및 검색을 위해 서로 다른 캐쉬 구조를 필요로 하는데, 전개 인코딩 방식으로 비압축 캐쉬를 압축 인코딩 방식으로 압축 캐쉬를 사용하고 있다. 그러나 이들은 각각 무효 연산어로 인한 메모리 활용 효율 저하와 복원 과정으로 인한 명령어 인출 오버헤드의 증가라는 문제점을 안고 있다. 본 논문에서는 부분적으로 명령어 길이를 일정하게 유지하는 부분 압축 인코딩을 사용해 메모리 활용 효율을 높이는 동시에 명령어 인출 오버헤드를 줄일 수 있는 분할 캐쉬 구조를 제안한다. 각 캐쉬 구조를 구현하는데 필요한 칩 영역을 계산하여, 분할 캐쉬가 비교적 비용 효율적인 캐쉬 구조임을 확인하였다. 모의 실험을 통한 메모리 활용 효율 측정 결과 하드웨어 비용의 증가를 고려하더라도 분할 캐쉬는 비압축 캐쉬에 비해 최고 약 3배의 메모리 활용 효율을 얻을 수 있었다. 각 캐쉬 구조를 일차 캐쉬로 하는 VLIW 시스템들의 성능 측정 결과는 TCSC(블록 집중형 분할 캐쉬)를 사용한 시스템이 비용 대비 성능 면에서 가장 우수한 것으로 나타났다.

• Journal of Digital Contents Society
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• v.17 no.5
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• pp.375-381
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• 2016

Recently, a foreground-background segmentation using codebook model has been researched actively. The codebook is created one for each pixel in the image. The codewords are vector-quantized representative values of same positional training samples from the input image sequences. The training is necessary for a long time in the most of codebook-based algorithms. In this paper, the initial codebook model is generated simply using median operation with several image frames. The initial codebook is updated to adapt the dynamic changes of backgrounds based on the frequencies of codewords that matched to input pixel during the detection process. We implemented the proposed algorithm in the environment of visual c++ with opencv 3.0, and tested to some of the public video sequences from PETS2009. The test sequences contain the various scenarios including quasi-periodic motion images, loitering objects in the local area for a short time, etc. The experimental results show that the proposed algorithm has good performance compared to the GMM algorithm and standard codebook algorithm.