• Journal of the Korean Society for Precision Engineering
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• v.14 no.6
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• pp.135-141
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• 1997

Low velocity impact test and compressive residual strength test after impact were performed by using Hercules AS4/3501-6[45/0/-45/90]$_{2s}$ laminated plate to investigate the low velocity impact damage behavior and the post-impact strength degradation on orthotropic composite laminate plate. Due to the lateral impact losd, the load path showed "" shape according to the laminate central deflection. Damage in a laminate occurs by inclined matrix crack at the damage initiation load stage and vertical matrix crack, occurs on the outer surface. Evaluating the compressive residual strength after the low velocty impact test, it could be found that there is a transient range where the compressive residual strength drop suddenly in the initial damage which is in the matrix crack range and the initial delamination area. is in the matrix crack range and the initial delamination area.

• Structural Engineering and Mechanics
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• v.19 no.1
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• pp.73-96
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• 2005

For the spatially coupled free vibration analysis of shear deformable thin-walled non-symmetric curved beam subjected to initial axial force, an exact dynamic element stiffness matrix of curved beam is evaluated. Firstly equations of motion and force-deformation relations are rigorously derived from the total potential energy for a curved beam element. Next a system of linear algebraic equations are constructed by introducing 14 displacement parameters and transforming the second order simultaneous differential equations into the first order simultaneous differential equations. And then explicit expressions for displacement parameters are numerically evaluated via eigensolutions and the exact $14{\times}14$ dynamic element stiffness matrix is determined using force-deformation relations. To demonstrate the accuracy and the reliability of this study, the spatially coupled natural frequencies of shear deformable thin-walled non-symmetric curved beams subjected to initial axial forces are evaluated and compared with analytical and FE solutions using isoparametric and Hermitian curved beam elements and results by ABAQUS's shell elements.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10b
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• pp.1051-1054
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• 1988

In this paper we present initial convergence properties of the Kalman filtering algorithm, we put an arbitrary small positive correlation matrix as an initial condition in the recursive algorithm. This arbitrary small initial condition perturbs the Kalman filtering algorithm and may lead to initial instability. We derive a condition which insures the stable operation of the Kalman filtering algorithm from the stochastic Lyapunov difference equation.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.211-215
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• 1989

The structure of A matrix of one machine connected to the infinite bus is described for a full model. The A matrix can be partitioned to submatrices which depend on the initial operating point and do not depend on it. When the dynamic properties for several different operating points are desired, those submatrices can be obtained through simple column operations. Furthermore, the elements of A matrix car be directly calculated from the manufacturer's data. RMS quantities of the state variables for the initial operating point are used. This approach can save the labor for calculating the elements of A matrix for the dynamic stability analysis.

• Proceedings of the Korean Society for Language and Information Conference
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• 2007.11a
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• pp.430-439
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• 2007

In this paper, we use non-negative matrix factorization (NMF) to refine the document clustering results. NMF is a dimensional reduction method and effective for document clustering, because a term-document matrix is high-dimensional and sparse. The initial matrix of the NMF algorithm is regarded as a clustering result, therefore we can use NMF as a refinement method. First we perform min-max cut (Mcut), which is a powerful spectral clustering method, and then refine the result via NMF. Finally we should obtain an accurate clustering result. However, NMF often fails to improve the given clustering result. To overcome this problem, we use the Mcut object function to stop the iteration of NMF.

• YAKHAK HOEJI
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• v.48 no.1
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• pp.6-12
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• 2004

Near-infrared spectra of methanol-water mixtures and acetonitrile-water mixtures were acquired to find interactions between solvents widely used for reverse-phase liquid chromatography. Mixtures were prepared to give a series of increasing mole fractions of methanol or acetonitrile in water. Data matrices of acquired spectra were analyzed to determine the proper number of principal components of each mixture system using Malinowski's factor indicator function. Initial guess of score matrix and loading matrix were calculated by nonlinear iterative partial least squares (NIPALS) algorithm for faster computation. Iterative target transform factor analysis (ITTFA) was applied to convert the initial estimation of score matrix to true concentration profile and loading matrix to pure spectra of pure components of the mixtures. In case of methanol-water the number of principal components was found to be 4 and those initial guess of factors were converted to the pure spectra of water methanol and two kinds of complexes. In case of acetonitrile-water the number of pure components of the mixtures was found to be 3 and the pure spectrum of acetonitrile-water complex was found. The nonlinear characteristics of concentration profiles of complexes in the solvent mixtures may give a good criteria in understanding their elution characteristics in reverse-phase liquid chromatogrsphy.

• Archives of Pharmacal Research
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• v.9 no.2
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• pp.87-91
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• 1986

In attempt to develop a drug delivery system using serum albumin microspheres, bovine serum albumin microspheres containing antitumar agent. Cytarabine, were prepared. The shape, surface characteristics, size distribution, behavior of in vivo distribution, drug release behavior, and degradation of albumin microsphers in animal liver issue homogenate and proteolytic enzyme were investigated. The shape of albumin microspheres was spherical and the surface was smooth and compact. The size distribution of the albumin microspheres was effected by dispertion forces during emulsification and albumin concentration. Distribution of albumin microspheres after imtravenous administration in rabbit was achieved immediately. In vitro, albumin microsphere matrix was so hard that it retained most of cytarabine except initial burst during the first 10 minutes, and the level of drug release during the initial burst was affected by heating temperature, drug/albumin microsphere matrix was so hard that it retained most of cytarabine except initial burst during the first 10 minutes, and the level of drug release during the initial burst was affected by heating temperature, drug/albumin concentration ratio and size distribution. After drug release test, the morphology of albumin microspheres was not changed. Albumin microsphere matrix was degraded by the animal liver issue homogenate and proteolytic enzyme. The degree of degradation was affected by heating temperature.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.4
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• pp.285-289
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• 2013

In switching from the track-seeking or track-jumping control mode to track-following control mode in hard disk drives or optical disk drives, initial values of the feedback controller are tuned to improve the transient response. In general, all the initial values of the controller have been compensated for this purpose. In this paper, by partially compensating initial values of digital controllers, we achieve a good performance of the transient response. In the proposed method for IVC (Intial Value Compensation), LMIs (Linear Matrix Inequalities) are used, which includes conditions for improving the performance of the transient response such as reducing a tracking error and control efforts. We obtain optimal initial values of the controller by solving an optimization problem with constraints represented by only one LMI. Although initial values of the controller are partially compensated, we can show that not only a sufficient performance of the transient response is obtained but also control efforts are diminished. The feasibility of the method is verified by simulation studies.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1694-1700
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• 2004

In this paper, we propose the AWLS/MFT (Adaptive Weighed Least Squares/ Modulation Function Technique) devised by A. E. Pearson et al. for the transfer function estimation of a modal system and investigate the performance of several algorithms, the Gram matrix method, a Luenberger Observer (LO), Least Squares (LS), and Recursive Least Squares (RLS), for the estimation of initial conditions. With the benefit of the Modulation Function Technique (MFT), we can separate the estimation problem into two phases: the transfer function parameters are estimated in the first phase, and the initial conditions are estimated in the second phase. The LO method produces excellent IC estimates in the noise free case, but the other three methods show better performance in the noisy case. Finally, we compared our result with the Prony based method. In the noisy case, the AWLS and one of the three methods - Gram matrix, LS, and RLS- show better performance in the output Signal to Error Ratio (SER) aspect than the Prony based method under the same simulation conditions.

• Journal of Multimedia Information System
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• v.4 no.4
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• pp.219-224
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• 2017

This paper is to introduce an application of face recognition algorithm in parallel. We have experiments of 25 images with different motions and simulated the image recognitions; grouping of the image vectors, image normalization, calculating average image vectors, etc. We also discuss an analysis of the related eigen-image vectors and a parallel algorithm. To develop the parallel algorithm, we propose a new type of initial matrices for eigenvalue problem. If A is a symmetric matrix, initial matrices for eigen value problem are investigated: the "optimal" one, which minimize ${\parallel}C-A{\parallel}_F$ and the "super optimal", which minimize ${\parallel}I-C^{-1}A{\parallel}_F$. In this paper, we present a general new approach to the design of an initial matrices to solving eigenvalue problem based on the new optimal investigating C with preserving the characteristic of the given matrix A. Fast all resulting can be inverted via fast transform algorithms with O(N log N) operations.