• Title/Summary/Keyword: sparse matrix

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Finite Element Software Package for Analysis of Electric Field Distribution in Human Body (유한요소법에 의한 인체내 전계분포 해석 용 소프트웨어의 개발)

  • Woo, Eung-Je
    • Proceedings of the KOSOMBE Conference
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    • v.1993 no.05
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    • pp.66-69
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    • 1993
  • We have developed a software package for the analysis of electric field distribution in human body. It includes the graphical finite element mesh generator, linear system of equations solver using sparse matrix and vector technique, and post-processor for the display of the results. This software package can be used in various research areas of biomedical engineering where we inject current or apply voltage to human body. The software package was developed on Macintosh II computer and the size of the model is only limited by the main memory.

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Analysis a LDPC code in the VDSL system (VDSL 시스템에서의 LDPC 코드 연구)

  • Joh, Kyung-Hyun;Kang, Hee-Hoon;Yi, Sang-Hoi;Na, Kuk-Hwan
    • Proceedings of the IEEK Conference
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    • 2006.06a
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    • pp.999-1000
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    • 2006
  • The LDPC Code is focusing a powerful FEC(Forward Error Correction) codes for 4G Mobile Communication system. LDPC codes are used minimizing channel errors by modeling AWGN Channel as VDSL system. The performance of LDPC code is better than that of turbo code in long code word on iterative decoding algorithm. LDPC code are encoded by sparse parity check matrix. there are decoding algorithms for a LDPC code, Bit Flipping, Message passing, Sum-Product. Because LDPC Codes use low density parity bit, mathematical complexity is low and relating processing time becomes shorten.

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Optical Misalignment Cancellation via Online L1 Optimization (온라인 L1 최적화를 통한 탐색기 비정렬 효과 제거 기법)

  • Kim, Jong-Han;Han, Yudeog;Whang, Ick Ho
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.7
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    • pp.1078-1082
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    • 2017
  • This paper presents an L1 optimization based filtering technique which effectively eliminates the optical misalignment effects encountered in the squint guidance mode with strapdown seekers. We formulated a series of L1 optimization problems in order to separate the bias and the gradient components from the measured data, and solved them via the alternating direction method of multipliers (ADMM) and sparse matrix decomposition techniques. The proposed technique was able to rapidly detect arbitrary discontinuities and gradient changes from the measured signals, and was shown to effectively cancel the undesirable effects coming from the seeker misalignment angles. The technique was implemented on embedded flight computers and the real-time operational performance was verified via the hardware-in-the-loop simulation (HILS) tests in parallel with the automatic target recognition algorithms and the intra-red synthetic target images.

Performance Optimization of Sparse Matrix Operation (희소 행렬 연산의 성능 최적화에 관한 연구)

  • 김경훈;김병수;임은진
    • Proceedings of the Korean Information Science Society Conference
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    • 2003.04a
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    • pp.130-132
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    • 2003
  • 계산 과학을 사용하는 응용 분야는 공학, 물리, 화학, 생명 과학에서 경제학까지 다양하다. 계산 과학에 사용되는 많은 알고리즘들은 행렬 연산을 포함하고 있으며 이 행렬은 크기가 크고 대부분의 원소가 0값을 갖는 희소 행렬일 경우가 많다. 본 논문에서는 희소 행렬의 연산 중, 희소 행렬 A와 밀집 벡터 x, y에 대하여 ylongleftarrowy+Ax와 ylongleftarrowy+$A^{T}$ Ax 의 두 가지 연산에 대한 계산 속도 개선 방법으로서 레지스터 재사용을 높이는 레지스터 블록화와 캐쉬 미스를 줄이기 위한 캐쉬 최적화 방법을 제안하며 또한 희소 행렬의 특성과 target 컴퓨터의 구조에 따라 정해지는 레지스터 블록 크기를 결정하는 방법을 설명한다. Preliminary결과로 이 방법을 Pentium III system상에서 실험한 결과를 보이는데 ylongleftarrowy+Ax 의 연산에 대하여는 2.5 배, ylongleftarrowy+$A^{T}$ Ax 의 연산에 대하여는 3.5 배까지의 성능 개선을 이룰 수 있다.

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Analysis of Polarization Mode Dispersion in Nonlinear Optical Pulse propagation by SS-FEM adopting Approximated Sparse Matrix (희귀 행렬 근사 S-FEM을 이용한 비선형 광펄스의 편광 모드 분산 해석)

  • 한대우;이호준;정백호
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.25 no.6A
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    • pp.825-832
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    • 2000
  • 광섬유 통신 시스템이 고속화되고 장거리를 전송하게 될 수록 편광모드 분산의 중요성은 더욱 부각되어 있다. 따라서 본 논문에서는 복굴절 광섬유에서 비선형 광펄스의 전파특성을 편광 모드 분산의 영향을 고려하여 시뮬레이션하였으며 이러한 현상이 발생되는 것을 알 수 있었다. 그리고 광섬유 비션형성에 의해서 GVD(Group Velocity Dispersion)와 마찬가기로 PMD(Polarization Mode Dispersion)에서도 부분적인 보상 현상이 나타남을 수치 결과를 통해 알 수 있었다. 이러한 광 전송 시뮬레이션을 구현하기 위해서 기존의 단계분할 푸리에 방식 (SS-FM, Split-Step Fourier Method)보다 장거리 전송시 오차의 발생이 적은 단계 분할 유한 요소법)SS-FEM, Split-Step Finite Element Method)을 적용하였으며, 또한 그 단점인 수행 속도를 개선한 희귀 행렬 근사 단계 분할 유한 요소법을 제안하였다. 그 결과 제안된 방법이 기존의 푸리에 연산법이나 일반적인 유한 요소법과 비교하여 더 빠른 수행 속도를 나타내는 것을 알 수 있었다.

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A Study on the Optimum Operational Control of Power System (전렬계통의 합리적 운용제어에 관한 연구)

  • 정재길;박영문
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.33 no.10
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    • pp.410-422
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    • 1984
  • This paper presents a new practical method for optimal active and reactive power control for the economic operation in electrical power system, and the programs are developed for digital computer solution. The major features and techniques of this paper are as follows: 1) The method is presented for finding the equivalent active power balance equation applying the sparse Jacobian matrix of power flow equation instead of using B constant as active power balance equation considering transmission loss, and thus for determining directly optimal active power allocation berween generator unitw satisfying the equality and inequality constraints. 2) The method is proposed for solving directly the optimum economim dispatch problem without using gradient method and penalty function for both active and reactive power control. As a result, the computing time are reduced and convergence characteristic is remarkably improved. 3) Unlike most of conventional methods which adopt the transmission loss as a objective function for reactive power control, the total fuel cost of themal power plant is adopted as objective function for both active and reactive power control. consequently, more reasonable and economic profit can be achieved.

Experimental Comparisons of Simplex Method Program's Speed with Various Memory Referencing Techniques and Data Structures (여러 가지 컴퓨터 메모리 참조 방법과 자료구조에 대한 단체법 프로그램 수행 속도의 비교)

  • Park, Chan-Kyoo;Lim, Sung-Mook;Kim, Woo-Jae;Park, Soon-Dal
    • IE interfaces
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    • v.11 no.2
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    • pp.149-157
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    • 1998
  • In this paper, various techniques considering the characteristics of computer memory management are suggested, which can be used in the implementation of simplex method. First, reduction technique of indirect addressing, redundant references of memory, and scatter/gather technique are implemented, and the effectiveness of the techniques is shown. Loop-unrolling technique, which exploits the arithmetic operation mechanism of computer, is also implemented. Second, a subroutine frequently called is written in low-level language, and the effectiveness is proved by experimental results. Third, row-column linked list and Gustavson's data structure are compared as the data structure for the large sparse matrix in LU form. Last, buffering technique and memory-mapped file which can be used in reading large data file are implemented and the effectiveness is shown.

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An Indirect Matrix Converter for Dual Output AC-Drive System (다출력 기능을 갖는 간접 매트릭스 컨버터 시스템)

  • Bak, Yeongsu;Lee, Eunsil;Lee, Kyo-Beum;Lim, Seongsoo
    • Proceedings of the KIPE Conference
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    • 2014.07a
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    • pp.112-113
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    • 2014
  • 본 논문에서는 3 상 입력 매트릭스 컨버터에서 한 레그를 추가하여 다출력 기능을 갖는 시스템을 제안한다. 본 시스템은 기존의 매트릭스 컨버터에서 스위치의 개수를 줄인 베리 스파스 (Very Sparse) 매트릭스 컨버터 토폴로지에서 인버터단에 스위치 두 개를 추가하여 3 상과 단상의 두 출력을 갖도록 한다. 두 개의 출력은 독립적으로 제어가 가능하며 하나의 시스템으로 두 개의 출력을 낼 수 있어 소형화가 가능하다. 제안한 토폴로지와 이에 대한 제어 기법은 시뮬레이션을 통해 검증한다.

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Blind modal identification of output-only non-proportionally-damped structures by time-frequency complex independent component analysis

  • Nagarajaiah, Satish;Yang, Yongchao
    • Smart Structures and Systems
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    • v.15 no.1
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    • pp.81-97
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    • 2015
  • Recently, a new output-only modal identification method based on time-frequency independent component analysis (ICA) has been developed by the authors and shown to be useful for even highly-damped structures. In many cases, it is of interest to identify the complex modes of structures with non-proportional damping. This study extends the time-frequency ICA based method to a complex ICA formulation for output-only modal identification of non-proportionally-damped structures. The connection is established between complex ICA model and the complex-valued modal expansion with sparse time-frequency representation, thereby blindly separating the measured structural responses into the complex mode matrix and complex-valued modal responses. Numerical simulation on a non-proportionally-damped system, laboratory experiment on a highly-damped three-story frame, and a real-world highly-damped base-isolated structure identification example demonstrate the capability of the time-frequency complex ICA method for identification of structures with complex modes in a straightforward and efficient manner.

Action Recognition with deep network features and dimension reduction

  • Li, Lijun;Dai, Shuling
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.2
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    • pp.832-854
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    • 2019
  • Action recognition has been studied in computer vision field for years. We present an effective approach to recognize actions using a dimension reduction method, which is applied as a crucial step to reduce the dimensionality of feature descriptors after extracting features. We propose to use sparse matrix and randomized kd-tree to modify it and then propose modified Local Fisher Discriminant Analysis (mLFDA) method which greatly reduces the required memory and accelerate the standard Local Fisher Discriminant Analysis. For feature encoding, we propose a useful encoding method called mix encoding which combines Fisher vector encoding and locality-constrained linear coding to get the final video representations. In order to add more meaningful features to the process of action recognition, the convolutional neural network is utilized and combined with mix encoding to produce the deep network feature. Experimental results show that our algorithm is a competitive method on KTH dataset, HMDB51 dataset and UCF101 dataset when combining all these methods.