• 제목/요약/키워드: direct communications

검색결과 615건 처리시간 0.026초

Codebook based Direct Vector Quantization of MIMO Channel Matrix with Channel Normalization

  • Hui, Bing;Chang, KyungHi
    • 한국통신학회논문지
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    • 제39A권3호
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    • pp.155-157
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    • 2014
  • In this paper, a novel codebook generation strategy is proposed. With the given codebooks, two codeword selection procedures are proposed and analyzed for generating the quantized multiple-input multiple-output (MIMO) channel state information (CSI). Furthermore, three different quantization and normalization strategies are analyzed. The simulation results suggest that the proposed 'quantized channel generation method 2' is the best strategy to reduce the quantization and normalization errors to generate the final quantized MIMO CSI.

Distribution-Free Tests for Cross-Over Design Data

  • Kim, Dong-Jae
    • Communications for Statistical Applications and Methods
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    • 제6권1호
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    • pp.151-158
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    • 1999
  • Distribution-free tests are proposed for AB/BA 2*2 cross-over design data based on placements introduced by Orban and Wolfe(1992). In this paper we suggest the homogeneity test or carry-over effects and also suggest the test for direct effects and the test for period effects under the same carry-over effects. The properties such as iterative asymptotic distribution for the proposed tests are discussed.

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Improved Blind Multipath Estimation for Long Code DS-CDMA

  • Yu Qian;Bi Guoan;Zhang Gaonan
    • Journal of Communications and Networks
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    • 제7권3호
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    • pp.278-283
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    • 2005
  • This paper proposes a blind channel estimation scheme for long code direct sequence code division multiple access (DS­CDMA) systems with multipath fading channels. This scheme combines the advantages of Toeplitz displacement and correlation matching methods to achieve improved performance. The basic idea is to remove the effects of noise and interferences with Toeplitz displacement operation and then estimate the multi path channel parameters with the correlation matching method. Simulation results are presented to show that the proposed scheme provides better MSE performance and robustness against the near-far problem.

Communications with a Brain-wave bio-potential based computer interface

  • Choi, Kyoung-Ho;Minoru, Sasaki
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2001년도 ICCAS
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    • pp.46.3-46
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    • 2001
  • The overall aim of this research is to develop a computer communication interface based on brain-wave bio potentials for physically disabled people. The work focuses on using EOG and EMG signals to input characters one by one using cursor movements on a GUI screen. The Cyberlink TM system is used to acquire brain waves in real time with electrodes. EMG and EOG signals are used to direct a cursor in order to select, or to click on a character on the screen. We present a novel method for automatic EOG pattern detection by using wavelet transforms with a neuro-fuzzy approach ...

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ROUGH ISOMETRY AND THE SPACE OF BOUNDED ENERGY FINITE SOLUTIONS OF THE SCHRODINGER OPERATOR ON GRAPHS

  • Kim, Seok-Woo;Lee, Yong-Hah;Yoon, Joung-Hahn
    • 대한수학회논문집
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    • 제25권4호
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    • pp.609-614
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    • 2010
  • We prove that if graphs of bounded degree are roughly isometric to each other, then the spaces of bounded energy finite solutions of the Schr$\ddot{o}$dinger operator on the graphs are isomorphic to each other. This is a direct generalization of the results of Soardi [5] and of Lee [3].

EFFICIENT PARALLEL ITERATIVE METHOD FOR SOLVING LARGE NONSYMMETRIC LINEAR SYSTEMS

  • Yun, Jae-Heon
    • 대한수학회논문집
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    • 제9권2호
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    • pp.449-465
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    • 1994
  • The two common numerical methods to approximate the solution of partial differential equations are the finite element method and the finite difference method. They both lead to solving large sparse linear systems. For many applications, it is not unusal that the order of matrix is greater than 10, 000. For this kind of problem, a direct method such as Gaussian elimination can not be used because of the prohibitive cost. To this end, many iterative methods with modest cost have been studied and proposed by numerical analysts.(omitted)

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A Simple Chi-squared Test of Multivariate Normality Based on the Spherical Data

  • Park, Cheolyong
    • Communications for Statistical Applications and Methods
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    • 제8권1호
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    • pp.117-126
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    • 2001
  • We provide a simple chi-squared test of multivariate normality based on rectangular cells on the spherical data. This test is simple since it is a direct extension of the univariate chi-squared test to multivariate case and the expected cell counts are easily computed. We derive the limiting distribution of the chi-squared statistic via the conditional limit theorems. We study the accuracy in finite samples of the limiting distribution and then compare the poser of our test with those of other popular tests in an application to a real data.

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On the Fitting ANOVA Models to Unbalanced Data

  • Jong-Tae Park;Jae-Heon Lee;Byung-Chun Kim
    • Communications for Statistical Applications and Methods
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    • 제2권1호
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    • pp.48-54
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    • 1995
  • A direct method for fitting analysis-of-variance models to unbalanced data is presented. This method exploits sparsity and rank deficiency of the matrix and is based on Gram-Schmidt orthogonalization of a set of sparse columns of the model matrix. The computational algorithm of the sum of squares for testing estmable hyphotheses is given.

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Performance Evaluation of Spectral Analysis System for TDX-families Signaling Service Equipment

  • Yoon, Dal-Hwan
    • 한국통신학회논문지
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    • 제26권10A호
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    • pp.1764-1771
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    • 2001
  • It has developed a PCM signal acquisition(PCMA) system which can analyze status of signals in order to establish rapid diagnosing in TDX-families signaling service equipment. We develop the quick Fourier transform(QFT) for length 2$\^$M/ data to analyze the power spectral of the PCMA system. This algorithm can reduces the number of floating-point operations necessary to compute the DFT by a factor of two or four over direct methods or Goertzels method for prime lengths. In the experimental results, the system classifies the type of signals and finally discriminates the digit.

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