• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.653-658
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• 2001

In this study, a new practical method of predicting the sound absorption coefficient for multiple perforated-plate sound absorbing system was developed using transfer matrix method. In order to validate the proposed method, the absorption coefficients calculated by transfer matrix method for single perforated plate were first compared with the absorption coefficients measured by SWR method according to different porosity, hole diameter, and thickness of the perforated plate. Based on the comparison results, transfer matrix method was further applied to double and triple perforated plates to evaluate the absorption coefficients. The experimental results showed that the absorption coefficients from transfer matrix method generally agreed well with the corresponding absorption coefficients from SWR method. However, due to the limitations of the impedance model used in this study, the measured values were differed with the calculated values for small porosity, hole diameter, and thickness in size of the perforated plate indicating the need of impedance model development for multiple perforated-plate sound absorbing system covering wide ranges of porosity, hole diameter, and thickness of the perforated plate.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.745-748
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• 1999

This paper propose the method to derive RM(Reed-Muller) expansion coefficients for Multiple-Valued function. The general method to obtain RM expansion coefficient for p valued n variable is derivation of single variable transform matrix and expand it n times using Kronecker product. The transform matrix used is p$^{n}$ $\times$ p$^{n}$ matrix. In this case the size of matrix increases depending on the augmentation of variables and the operation is complicated. Thus, to solving the problem, we propose derivation of RM expansion coefficients using p$\times$p transform matrix and Karnaugh-map.

• Journal of the Korean Data and Information Science Society
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• 제23권5호
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• pp.1037-1044
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• 2012

Multivariate control charts for effectively monitoring every component in the dispersion matrix of multivariate normal process are considered. Through the numerical results, we noticed that the multivariate control charts based on sample statistic $V_i$ by Hotelling or $W_i$ by Alt do not work effectively when the correlation coefficient components in dispersion matrix are increased. We propose a combined procedure monitoring every component of dispersion matrix, which operates simultaneously both control charts, a chart controlling variance components and a chart controlling correlation coefficients. Our numerical results show that the proposed combined procedure is efficient for detecting changes in both variances and correlation coefficients of dispersion matrix.

• 한국통신학회논문지
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• 제30권9C호
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• pp.860-870
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• 2005

본 논문에서는 karnaugh map(k-map)상의 셀을 이용하여 $2^{n}$개의 서로 다른 극수(polarity)를 갖는 GRM(Generalized Reed-Muller)상수를 생성하는 새로운 기법을 제안하였다. n개의 입력변수에 대한 일반적인 GRM 함수의 생성 방법은 단일 변수에 대한 변환 행렬을 구하고 이를 n번의 Kronecker 곱을 행한 변환 행렬을 이용하여 GRM 상수를 구하는 것이다. 이런 방법을 사용하는 경우, 변수의 숫자가 증가함에 따라 변환 행렬의 차수가 $2^{n}\times2^{n}$로 커지는 단점을 갖는다. 이에 반하여 본 논문에서는 k-map상에서 변수를 축약시킨 셀 [$f_{i}$]을 구하고 이를 단일 변수 변환 행렬과 연산하여 GBM 상수를 구하는 새로운 기법을 제안한다. 본 논문에서 제안한 새로운 방법과 타 논문과의 비교를 한 결과, 기존 방법은 가산기, 승산기, KP(Kronecker 곱 승산기)회로가 필요한데 반하여 본 논문에서는 가산기만이 필요하므로 효율적인 VLSI 설계에 유리하다

• 한국해양공학회지
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• 제19권5호
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• pp.1-15
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• 2005

The motion behaviors including hydrodynamic interaction and mechanical coupling effects on multiple-body floating platforms are simulated by using a time domain hull/mooring/riser coupled dynamics analysis program. The objective of this study is to evaluate off-diagonal hydrodynamic interaction effects and mechanical coupling effects on tandem moored FPSO and shuttle taker motions. In the multiple-body floating platforms interaction, hydrodynamic coupling effects with waves and mechanical coupling effects through the connectors should be considered. Thus, in this study, the multiple-body platform motions are calculated by Combined Matrix Method (CMM) as well as Separated Matrix Method (SMM). The advantage of the combined matrix method is that it can include all the 6Nx6N full hydrodynamic and mechanical interaction effects among N bodies. Whereas, due to the larger matrix size, the calculation time of Combined Matrix Method (CMM) is longer than the Separated Matrix Method (SMM). On the other hand, Separated Matrix Method (SMM) cannot include the off-diagonal 6x6 hydrodynamic interaction coefficients although it can fully include mechanical interactions among N bodies. To evaluate hydrodynamic interaction and mechanical coupling effects, tandem moored FPSO and shuttle tanker is simulated by Combined Matrix Method (CMM) and Separated Matrix Method (SMM). The calculation results give a good agreement between Combined Matrix Method (CMM) and Separated Matrix Method (SMM). The results show that the Separated Matrix Method (SMM) is more efficient for tandem moored FPSO and shuttle tanker. In the numerical calculation, the hydrodynamic coefficients are calculated from a 3D diffraction/radiation panel program WAMIT, and wind and current forces are generated by using the respective coefficients given in the OCIMF data sheet.

• 융합신호처리학회논문지
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• 제2권1호
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• pp.63-70
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• 2001

EZW(Embedded Image Coding Using Zerotrees of Wavelet Coefficients) 알고리즘의 경우는 해상도를 높이기 위해 임계값을 낮출 때 중요계수의 위치를 나타내기 위해 필요 없는 zero 값을 많이 코딩을 해야 하는 문제가 있다. 본 논문에서는 이러한 문제점을 해결하기 위하여 쿼드 트리(quad tree)방법을 이용하여 위치정보를 나나내었다. 그리고 그 계수들의 크기는 EZW 에서 사용한 방법과 유사한 메트릭스(matrix) 방법을 사용하였다. 본 논문에서 제안한 알고리즘으로 영상을 압축하게 되면 EZW와 MRWD(Morphological Representation of Wavelet Data)의 방법을 동시에 이용하는 효과가 있어 압축 효율이 증가함을 알 수 있었다.

• Communications for Statistical Applications and Methods
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• 제22권6호
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• pp.665-674
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• 2015

Lack of a general matrix formula hampers implementation of the semi-partial correlation, also known as part correlation, to the higher-order coefficient. This is because the higher-order semi-partial correlation calculation using a recursive formula requires an enormous number of recursive calculations to obtain the correlation coefficients. To resolve this difficulty, we derive a general matrix formula of the semi-partial correlation for fast computation. The semi-partial correlations are then implemented on an R package ppcor along with the partial correlation. Owing to the general matrix formulas, users can readily calculate the coefficients of both partial and semi-partial correlations without computational burden. The package ppcor further provides users with the level of the statistical significance with its test statistic.

• Steel and Composite Structures
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• 제34권5호
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• pp.671-679
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• 2020

The new energy-based criterion, named Reinforcement Strain Energy Density (ReiSED), is proposed to investigate the fracture behavior of the cracked orthotropic materials in which the crack is embedded in the matrix along the fibers. ReiSED is an extension of the well-known minimum strain energy density criterion. The concept of the reinforced isotropic solid as an advantageous model is the basis of the proposed mixed-mode I/II criterion. This model introduces fibers as reinforcements of the isotropic matrix in orthotropic materials. The effects of fibers are qualified by defining reinforcement coefficients at tension and shear modes. These coefficients, called Reduced Stress (ReSt), provide the possibility of encompassing the fiber fraction in a fracture criterion for the first time. Comparing ReiSED fracture limit curve with experimental data proves the high efficiency of this criterion to predict the fracture behavior of orthotropic materials.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제53권10호
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• pp.539-545
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• 2004

In this paper, we consider the problem of capacitance matrix calculation for strip-line and other interconnects crossings. The problem is formulated in the spectral domain using the method of moments. Sinc-functions are employed as basis functions. Conventionally, such a formulation leads to a large, non-sparse system of linear equations in which the calculation of each of the coefficient requires the evaluation of a Fourier-Bessel integral. Such calculations are computationally very intensive. In the method proposed here, we provide simplified expressions for the coefficients in the moment method matrix. Using these simplified expressions, the coefficients can be calculated very efficiently. This leads to a fast evaluation of the capacitance matrix of the structure. Computer simulations are provided illustrating the validity of the method proposed.

• Structural Engineering and Mechanics
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• 제7권3호
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• pp.259-276
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• 1999

An analytical solution for the shape functions of a beam segment supported on a generalized two-parameter elastic foundation is derived. The solution is general, and is not restricted to a particular range of magnitudes of the foundation parameters. The exact shape functions can be utilized to derive exact analytic expressions for the coefficients of the element stiffness matrix, work equivalent nodal forces for arbitrary transverse loads and coefficients of the consistent mass and geometrical stiffness matrices. As illustration, each distinct coefficient of the element stiffness matrix is compared with its conventional counterpart for a beam segment supported by no foundation at all for the entire range of foundation parameters.