• 제어로봇시스템학회논문지
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• 제18권9호
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• pp.806-811
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• 2012

In this paper Hartley functions are used to approximate the solutions of continuous time linear dynamical system. The Hartley function and its integral operational matrix are first presented, an efficient algorithm to solve the Stein equation is proposed. The algorithm is based on the compound matrix and the inverse of sum of matrices. Using the structure of the Hartley's integral operational matrix, the full order Stein equation should be solved in terms of the solutions of pure algebraic matrix equations, which reduces the computation time remarkably. Finally a numerical example is illustrated to demonstrate the validity of the proposed algorithm.

• 한국구조물진단유지관리공학회 논문집
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• 제20권4호
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• pp.27-34
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• 2016

시설물의 거동 파악을 위한 대표적인 방법으로는 가속도센서에서 측정되는 동적응답을 이용하여 역해석을 통해 구조변수를 추정하는 방법이 있다. 정확한 구조변수의 추정을 위해서는 최적화된 센서의 위치가 필요한데, 본 논문에서는 다양한 최적 센서위치를 추정하는 방법을 정리하였으며, 기존 시간영역에서만 사용되었던 Hankel matrix법을 주파수영역으로 확대 개발하여 기존 최적 센서위치 추정 방법들과 결과를 비교 분석하였다. 결과 비교 및 검증을 위해 지진동에 의한 동적 해석을 수행하여 기존 및 새로운 방법으로 선택된 최적 센서위치 에서의 가속도데이터를 활용하여 FFT(Fast Fourier Transform)를 통해 진동 형상의 크기를 구하고, spline function으로 전체 자유도에 대한 진동 형상을 추정하였으며, 추정된 진동 형상과 해석적으로 구해진 진동 형상과의 MAC 지수를 통하여 다양한 방법들의 모드 추정의 정확도를 비교하였다.

• 제어로봇시스템학회논문지
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• 제14권7호
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• pp.615-623
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• 2008

This paper proposes an $H_{\infty}$ controller design method for Takagi-Sugeno (T-S) fuzzy systems using a fuzzy basis-function-dependent Lyapunov function. Sufficient conditions for the guaranteed $H_{\infty}$ performance of the T-S fuzzy control system are given in terms of linear matrix inequalities (LMIs). These LMI conditions are further used for a convex optimization problem in which the $H_{\infty}-norm$ of the closed-loop system is to be minimized. To facilitate the basis-function-dependent Lyapunov function approach and thus improve the closed-loop system performance, additional decision variables are introduced in the optimization problem, which provide an additional degree-of-freedom and thus can enlarge the solution space of the problem. Numerical examples show the effectiveness of the proposed method.

• 호남수학학술지
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• 제43권1호
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• pp.141-151
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• 2021

The main object of the present paper is to introduce the generalized Laguerre matrix polynomials for two variables. We prove that these matrix polynomials are characterized by the generalized hypergeometric matrix function. An explicit representation, generating functions and some recurrence relations are obtained here. Moreover, these matrix polynomials appear as solution of a differential equation.

• Korean Journal of Mathematics
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• 제29권4호
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• pp.811-824
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• 2021

The main aim of this paper is to introduce the definitions of generalized order and generalized type of the entire function of complex matrices and then study some of their properties. By considering the concepts of generalized order and generalized type, we will extend some results of Kishka et al. [5].

• 한국산학기술학회논문지
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• 제16권8호
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• pp.5260-5266
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• 2015

무기체계 개발 시 종합군수지원 측면에서 중요한 것 중 하나가 동시조달수리부속 산출이다. 동시조달수리부속은 무기체계 가용도 향상 측면에서 매우 중요한 것으로, 이에 대한 다양한 연구가 이루어지고 있다. 그러나 대부분의 연구는 하부 구성품의 고장이 무기체계의 다양한 기능에 미치는 세부 영향들을 고려하지 못하고 있다. 즉 하부 구성품의 고장이 무기체계의 특정 기능에 미치는 영향이 미비하면, 구성품 교환과 같은 정비가 필요 없다는 점을 고려하지 못한다. 그래서 본 연구에서는 고장-기능 간 관계도를 이용하여, 하부 구성품의 고장이 무기체계의 다양한 기능에 미치는 세부 영향을 고려한 동시조달수리부속 산출 방법을 기술하였다. 본 연구 절차는 다음과 같다. 첫째, 무기체계의 운용 및 정비 시스템을 분석한다. 둘째, 고장-기능 간 관계도를 개발한다. 셋째, 수집된 자료를 바탕으로 시뮬레이션 모델을 설계 한다. 마지막으로, 시뮬레이션과 메타 휴리스틱 모형인 진화 전략을 통해 동시조달수리부속 최적 수량을 선정한다. 해당 연구는 동시조달수리부속 산출 연구에 새로운 방향을 제시하였다.

• 대한기계학회논문집
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• 제15권2호
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• pp.445-454
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• 1991

In this thesis, Mindlin plate element with nine nodes and three degrees-of-freedom at each node is formulated and is employed in eigen-analysis of a rectangular plates in order to alleviate locking phenomenon of eigenvalues. Eigenvalues and their modes may be locked if conventional $C_{0}$-isoparametric element is used. In order to reduce stiffness locking phenomenon, two methods (1, the general reduced and selective integration, 2, the new element that use of modified shape function) are studied. Additionally in order to reduce the error due to mass matrix, two mass matrixes (1, Gauss-Legendre mass matrix, 2, Gauss-Lobatto mass matrix) are considered. The results of eigen-analysis for two models (the square plate with all edges simply-supported and all edges built-in), computed by two methods for stiffness matrix and by two mass matrixes are compared with theoretical solutions and conventional numerical solutions. These comparisons show that the performance of the two methods with Gauss-Lobatto mass matrix is better than that of the conventional plate element. But, by considering the spurious rigid body motions, the element which employs modified shape function with full integration and Gauss-Lobatto mass matrix can elevate the accuracy and convergence of numerical solutions.

• 품질경영학회지
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• 제21권1호
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• pp.199-213
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• 1993

The function-cost matrix table is not constant, but can be changed by many factors including equipment capacity, level of production technique, fluctuation of production volume, and the continuous development of products. Such changes would give the VE analysists additional work burden. By using computer. in this study, much of the time and effort of the function evaluation could be saved, and the efficiency of the analysis could also be enhanced. The application of the function evaluation data of R Company, as a case analysis, to the function evaluation computer program developed in this study resulted in the faster management of function-cost matrix table and function evaluation.

• The Korean Journal of Pain
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• 제36권1호
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• pp.72-83
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• 2023

Background: Globally, spinal cord injury (SCI) results in a big burden, including 90% suffering permanent disability, and 60%-69% experiencing neuropathic pain. The main causes are oxidative stress, inflammation, and degeneration. The efficacy of the stem cell secretome is promising, but the role of human neural stem cell (HNSC)-secretome in neuropathic pain is unclear. This study evaluated how the mechanism of HNSC-secretome improves neuropathic pain and locomotor function in SCI rat models through antioxidant, anti-inflammatory, anti-matrix degradation, and neurotrophic activities. Methods: A proper experimental study investigated 15 Rattus norvegicus divided into normal, control, and treatment groups (30 µL HNSC-secretome, intrathecal in the level of T10, three days post-traumatic SCI). Twenty-eight days post-injury, specimens were collected, and matrix metalloproteinase (MMP)-9, F2-Isoprostanes, tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-β, and brain derived neurotrophic factor (BDNF) were analyzed. Locomotor recovery was evaluated via Basso, Beattie, and Bresnahan scores. Neuropathic pain was evaluated using the Rat Grimace Scale. Results: The HNSC-secretome could improve locomotor recovery and neuropathic pain, decrease F2-Isoprostane (antioxidant), decrease MMP-9 and TNF-α (anti-inflammatory), as well as modulate TGF-β and BDNF (neurotrophic factor). Moreover, HNSC-secretomes maintain the extracellular matrix of SCI by reducing the matrix degradation effect of MMP-9 and increasing the collagen formation effect of TGF-β as a resistor of glial scar formation. Conclusions: The present study demonstrated the mechanism of HNSC-secretome in improving neuropathic pain and locomotor function in SCI through antioxidant, anti-inflammatory, anti-matrix degradation, and neurotrophic activities.

• 제어로봇시스템학회논문지
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• 제5권7호
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• pp.808-813
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• 1999

A fuzzy learning method to control an unstable and multivariable system is presented in this paper, Because the multivariable system has generally a coupling effect between the inputs and outputs, it is difficult to find its modeling equation or parameters. If the system is unstable, initial condition rules are needed to make it stable because learning is nearly impossible. Therefore, this learning method uses the initial rules and introduces a cost function composed of the actual error and error-rate of each output without the modeling equation. To minimize the cost function, we experimentally got the Jacobian matrix in the operating point of the system. From the Jacobian matrix, we can find the direction of the convergence in the learning, and the optimal control rules are finally acquired when the fuzzy rules are updated by changing the portion of the errors and error rates.