• Information and Communications Magazine
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• v.32 no.10
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• pp.41-47
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• 2015

본고에서는 해밍(Hamming) 부호화된 미지의 신호를 바탕으로 전송된 채널 코딩의 종류에 대해서 알아낼 수 있는 알고리즘을 제안한다. 우선 해밍 코드의 부호화, 복호화 과정을 설명한다. (n,k) 해밍 코드의 부호화 과정을 위하여 사용되는 제너레이터 행렬 G는 (k * n)의 크기를 갖게 되며 복호화 과정을 위하여 사용되는 패리티 체크 행렬 H는 (n-k * n)의 크기를 갖게 된다. 그리고 설계한 알고리즘의 동작원리를 수신 신호의 상태에 따라 설명한다. 수신 신호의 앞에 프리앰블이 있는 경우나 수신신호가 Inverse 또는 Reverse 되어 있는 등 여러 경우에 대비한 알고리즘 설계 방법을 알아본다. 이렇게 설계한 알고리즘은 복잡도가 낮고 확장이 용이하며 수신 신호의 코드워드의 시작점을 쉽게 알 수 있는 장점을 가지고 있어 일반 사용자의 통신 시스템 뿐만 아니라 군사용 통신 체계에 적용하기에도 적합하다.

• Journal of Korean Society of Transportation
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• v.16 no.3
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• pp.25-36
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• 1998

고속도로의 Tollgate는 상습 정체지역으로 개선방안이 시급히 요구되어진다. 이에 본 연구는 요금징수소 정체 해결의 기본자료로서 중요한 역할을 수행할 요금징수소의 평균 서비스시간 산정, 설계교통량 결정 및 서비스수준 결정 규정을 제시하였다. 연구방법으로는 공간적인 연구범위인 경주 Tollgate의 교통류 특성을 비데오 카메라로 촬영하여 이를 서비 스시간 측정기를 사용하여 포화서비스시간을 분석하였다. 이를 통하여 포화교통류율을 산정 하였고, 또한 중차량 포화서비스시간을 산정하여 중차량 보정 및 승용차 환산계수를 제시하 였다. 설문지 조사를 통한 운전자의 서비스수준 결정인자와 방법에 대해 조사하고 SPSS를 사용하여 분석하였다. 그리고 설계교통량 결정을 위해서 대기행렬대수 및 대기행렬 지속시 간을 매개변수로 하여 경제성 분석을 실시하였으며, 이를 통하여 게이트 수 결정 방법을 제 시하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.1A
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• pp.34-42
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• 2012

Low density parity check (LDPC) code is widely used, since it shows superior performance close to Shannon limit and its decoding complexity is lower than turbo code. Recently, it is used as a channel code to decode Wyner-Ziv frames in distributed video coding (DVC) system. In this paper, we propose an efficient method to design the parity check matrix H of LDPC codes. In order to apply LDPC code to DVC system, the LDPC code should have rate compatibility. Thus, we also propose a method to merge check nodes of LDPC code to attain the rate compatibility. LDPC code is designed using ACE algorithm and check nodes are merged for a given code rate to maximize the error correction capability. The performance of the designed LDPC code is analyzed extensively by computer simulations.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1994.10a
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• pp.193-193
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• 1994

• KIPE Magazine
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• v.26 no.1
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• pp.80-85
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• 2021

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.5
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• pp.77-83
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• 1993

A modified Lanczos method combined with a substructure analysis technique was used for calculating natural frequencies and mode shapes of large structural systems. The method does not require generation and storage of stiffness and mass matrices of the entire structure. It only uses the stiffness and mass matrices of each substucture. No approximating assumptions are required other than the usual assumption of linear elastic system modelled by finite elements. Thus, natural frequencies and mode shapes for the finite element model employed are the same as those with or without the suhstructuring algorithm. To check the efficiency of the proposed method, first ten natural frequencies and the corresponding mode shapes of an open truss helicopter tail-boom structure are calculated by using it.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.1
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• pp.35-46
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• 2004

In comparison with edge-emitting lasers(EELs), predicting the output power and slope efficiency of Vertical-Cavity Surface-Emitting Lasers(VCSELs) is very difficult due to the absorption loss in DBR layers. However, by using transfer matrix method(TMM), we've made possible to calculate such parameters of multi-layer structures like VCSELs. In this paper, we've calculated the threshold gain, threshold current and slope efficiency through the methodology based on TMM. Also TMM is the way of customizing the VCSEL structure for the desired threshold current and slope efficiency by changing the number of DBR mirror layers.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.3
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• pp.561-573
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• 2018

In order to design the ventilation in the road tunnel, it is necessary to know the ratio of average annual daily traffic by vehicle type. In general, the road tunnels are onedirectional tunnel, so the traffic of each vehicle type does not change along the tunnel. On the other hand, in the case of network road tunnels, since the connections in the tunnels are complex, the traffic of vehicle-type varies depending on the network composition of tunnels. In the studying the easy method for calculating the ratio of vehicle type for the network road tunnel are proposed with using incidence matrix.

• The Journal of the Acoustical Society of Korea
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• v.18 no.8
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• pp.61-67
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• 1999

This paper proposes a new beamforming algorithm for acoustic measurement by using the nested linear array. In this algorithm, the weighting is optimized by minimizing the LMS error with the initial value obtained by FIR filter design algorithm. The optimization process is applied to each sub-band, which is divided from the octave band, to produce the uniform directivity index. For the optimization pseudo inverse matrix is used for the transfer matrix. As the simulation results, it is found that the proposed algorithm can get the desired beam pattern and unform directivity index so as to be used efficiently for the acoustic measurement by using a nested linear array.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.3
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• pp.122-130
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• 2001

Axiomatic Design is the useful tool for making a good design. In Axiomatic design, the independency is an important property to determine whether the design is good. Until now many designers decide the independency between FRs by their own decision. The way depending on inspiration is simple and fast, but it can not be considered as precise conclusion. Also there are not exact rule that evaluate the quantitative independency between FRs. This thesis will show the way to evaluated the quantitative independency of FRs from the comparison between FRs of more lower levels, and develop more efficient and objective tool in Axiomatic Design.