• International journal of advanced smart convergence
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• 제9권4호
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• pp.42-51
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• 2020

In this paper, the authors propose the pseudo complex correlation coefficient (PCCC) of the two complex random variables (RV), because the four real correlation coefficients (RCC) of the corresponding four real RVs cannot be obtained only from the complex correlation coefficient (CCC) of given two complex RV. Such observation is motivated by the general statement; "The complex jointly-Gaussian random M-vector cannot be completely described by the complex covariance matrix, even though the real Gaussian random 2M-vector can be completely descried by the real covariance matrix. Therefore, in order to describe completely the complex jointly-Gaussian random M-vector, we need an additional matrix, namely the complex pseudo-covariance matrix, along with the complex covariance matrix." Then, we apply PCCC to correlated information sources (CIS) for non-orthogonal multiple access (NOMA) in 5G system, and investigate impact of the proposed PCCC on the achievable data rate of the stronger channel user in the conventional successive interference cancellation (SIC) NOMA with CIS. It is shown that for the given same CCC, the achievable data rates with the different PCCC are different, because the corresponding RCC are different. We also show that as the absolute value of the same CCC increases, the impact of the different PCCC becomes more significant.

• Coupled systems mechanics
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• 제10권6호
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• pp.509-520
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• 2021

Fiber-reinforced concrete (FRC) is a composite material where small fibers made from steel or polypropylene or similar material are embedded into concrete matrix. In a material model each constituent should be adequately described, especially the interface between the matrix and fibers that is determined with the 'bond-slip' law. 'Bond-slip' law describes relation between the force in a fiber and its displacement. Bond-slip relation is usually obtained from tension laboratory experiments where a fiber is pulled out from a matrix (concrete) block. However, theoretically bond-slip relation could be determined from bending experiments since in bending the fibers in FRC get pulled-out from the concrete matrix. We have performed specially designed laboratory experiments of three-point beam bending with an intention of using experimental data for determination of material parameters. In addition, we have formulated simple layered model for description of the behavior of beams in the three-point bending test. It is not possible to use this 'forward' beam model for extraction of material parameters so an inverse model has been devised. This model is a basis for formulation of an inverse model that could be used for parameter extraction from laboratory tests. The key assumption in the developed inverse solution procedure is that some values in the formulation are known and comprised in the experimental data. The procedure includes measured data and its derivative, the formulation is nonlinear and solution is obtained from an iterative procedure. The proposed method is numerically validated in the example at the end of the paper and it is demonstrated that material parameters could be successfully recovered from measured data.

• 통합자연과학논문집
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• 제7권3호
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• pp.208-213
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• 2014

National-wide and/or large scale sample surveys generally use complex sample design. Traditional Pearson chi-square test is not appropriate for the categorical complex sample data. Rao-Scott suggested an adjustment method for Pearson chi-square test, which uses the average of eigenvalues of design matrix of cell probabilities. This study is to compare the efficiency of Rao-Scott first order adjusted test to Wald test for homogeneity between two populations using 2009 Gyeongnam regional education offices's customer satisfaction survey (2009 GREOCSS) data. The 2009 GREOCSS data were collected based on stratified three-stage cluster sampling with probability proportional to size. The empirical results show that the Rao-Scott adjusted test statistic using only the variances of cell probabilities is very close to the Wald test statistic, which uses the covariance matrix of cell probabilities, under the 2009 GREOCSS data based. However it is necessary to be cautious to use the Rao-Scott first order adjusted test statistic in the place of Wald test because its efficiency is decreasing as the relative variance of eigenvalues of the design matrix of cell probabilities is increasing, specially more when the number of degrees of freedom is small.

• 디지털콘텐츠학회 논문지
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• 제19권4호
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• pp.731-737
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• 2018

추천 시스템은 컨텐츠, 온라인 커머스, 소셜 네트워크, 광고 시스템 등 많은 분야에서 사용자가 관심 있을 만한 정보를 선별 제안함을 목적으로 활발하게 연구되고 있다. 그러나 과거 선호도 데이터를 기반으로 제안하는 추천시스템이 많고 과거 데이터가 적거나 없는 사용자를 대상으로는 제공하기 어려우므로 낮은 성능을 보인다는 부문에서 문제점이 있다. 따라서 더욱 고차원적인 데이터 분석에 관한 관심이 증가하고 있고 Matrix Factorization이 주목받고 있다. 이 논문은 그 중 추천시스템에서 주목받는 Factorization Machines Learning(FM)모델과 고차원 데이터 분석인 High-order Factorization Machines Learning(HOFM)의 비교와 재연을 연구하고 제안 한다.

• 응용통계연구
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• 제8권1호
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• pp.51-60
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• 1995

크기가 $n \times p$인 자료행렬에서 p개의 변수들과 성격이 다소 다른 $p_s$개의 변수를 같이 고려한 크기가 $n \times (p + p_s)$ 자료행렬이 있다 하자. 전통적 주성성분분석은 성격이 다른 변수들로 인하여 효과적인 결과를 제공하지 못한다. 본 논문에서는 이런 점을 개선하기 위해서 성격이 다른 $p_s$개의 변수를 추가변수로 두는 추가적 주성분분석을 소개하려 한다. 이 기법은 전통적 주성분분석의 대수적,기하적인 면을 따른다. 그리고 전통적 주성분분석과 추가적 주성성분분석을 활용한 한국 프로야구의 8개팀과 1982-1992년 동안의 14개의 부문별 기록에 대한 전형적인 자료분석의 한 예를 제시한다. 더불어 두 분석의 결과도 비교하였다.

• 자연과학논문집
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• 제7권
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• pp.27-35
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• 1995

정지영상이나 동영상 코딩에 적용되는 2-D DCT의 효율적인 VLSI 구현을 위한 방법을 제시하였다. 2차원 상태공간식에 근거한 알고리즘 및 데이타 분할기법을 활용하여 다중프로세서 구조에서 문제가 되는 프로세서간의 통신량을 크게 감축시켰으며, 모든 통신을 국부적(local)이 되도록 하였다. 순차 주사 방식의 영상데이타를 입력할 수 있도록 설계하여 입력장치에 소요되는 하드웨어를 최소화하였으며, 계산의 순서를 조정함으로써 일반적인 행.열 분할 방법을 사용하는 2-D DCT에서 필요로 하는 Transposition RAM을 제거하였다. 제안된 VLSI 구조는 실시간 one-chip 2-D DCT 및 보다 큰 2-D DCT로 확장될 수 있다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권2호
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• pp.471-485
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• 2023

As data sharing increases explosively, such information encoded in QR code is completely public as private messages are not securely protected. This paper proposes a new 'PROMISE' framework for hiding information based on the QR code projection matrix by using image segmentation without modifying the essential QR code characteristics. Projection matrix mapping, matrix scrambling, fusion image segmentation and steganography with SEL(secret embedding logic) are part of the PROMISE framework. The QR code could be mapped to determine the segmentation site of the fusion image as a binary information matrix. To further protect the site information, matrix scrambling could be adopted after the mapping phase. Image segmentation is then performed on the fusion image and the SEL module is applied to embed the secret message into the fusion image. Matrix transformation and SEL parameters should be uploaded to the server as the secret key for authorized users to decode the private message. And it was possible to further obtain the private message hidden by the framework we proposed. Experimental findings show that when compared to some traditional information hiding methods, better anti-detection performance, greater secret key space and lower complexity could be obtained in our work.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 추계학술대회 논문집
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• pp.96-100
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• 2001

A method is presented for determining the free vibration characteristics of a rotating blade having nonuniform span wise properies and cantilevers boundary condition. The equations which govern the coupled the coupled flapwise, choirwise, and torsional motion of such a blade are solved using an integrating matrix method. By expressing the equation of motion in matrix notation, utilizing the integrating matrix as an operator, and applying the boundary condition, the equations are formulated into an eigenvalues problem whose solution may be determined by conventional method. Computer results are compared with experimental data.

• 한국데이터정보과학회:학술대회논문집
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• 한국데이터정보과학회 2003년도 춘계학술대회
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• pp.89-95
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• 2003

Cumulative sum(CUSUM) control charts for monitoring dispersion matrix under multivariate normal process are proposed. Performances of the proposed CUSUM charts are measured in terms of average run length(ARL) by simulation. Numerical results show that small reference values of the proposed CUSUM chart is more efficient for small shifts in the production process.

• 한국공작기계학회논문집
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• 제12권6호
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• pp.50-55
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• 2003

This study proposed the analysis of damage detection due to the change of the stiffness of structure by using the original and modified dynamic characteristics. The present approach allows the use of composite data which consist of eigenvalues and eigenvectors. The suggested method is applied to examples of a cantilever and 3 degree of freedom system by modifying the stiffness. The predicted damage detections are in good agreement with these from the structural reanalysis using the modified stiffness.