• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.614-618
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• 2003

This paper presents a system identification (SI) scheme in time domain using measured acceleration data. The error function is defined as the time integral of the least square errors between the measured acceleration and the calculated acceleration by a mathmatical model. Damping parameters as well as stiffness properties of a structure are considered as system parameters. The structural damping is modeled by the Rayleigh damping. A new regularization function defined by the L$_1$-norm of the first derivative of system parameters with respect to time is proposed to alleviate the ill-posed characteristics of inverse problems and to accommodate discontinuities of system parameters in time. The time window concept is proposed to trace variation of system parameters in time.

• 제어로봇시스템학회논문지
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• 제13권6호
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• pp.581-588
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• 2007

In this paper, we propose a delayed feedback guaranteed cost controller design method for linear time-delay systems with norm-bounded parameter uncertainties and nonlinear perturbations. A quadratic cost function is considered as the performance measure for the given system. Based on the Lyapunov method, an LMI optimization problem is formulated to design a controller such that the closed-loop cost function value is not more than a specified upper bound for all admissible system uncertainties and nonlinear perturbations. Numerical example show the effectiveness of the proposed method.

• Journal of Korean Biological Nursing Science
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• 제17권1호
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• pp.1-10
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• 2015

Purpose: This study is aimed at grasping the benefit/effect of program promoting intention to exercise performance based theory of planned behavior in the elderly who live in the rural areas with degenerative joint diseases (DJDs). Methods: There were 2 groups; 32 people in the experimental group and 24 in the control group, all above the age of 60. Program promoting intention to exercise performance was applied to the experimental group for 12 weeks. Results: Compared to the control group, the experimental group showed a significant the increase of attitude towards exercise, subjective norm, perceived behavior control, exercising intention, and exercise performance. Also, pain as a physical function, joint stiffness, ADLs, body flexibility, parallel, perceived health state as a psychological function, and life satisfaction were significantly improved. Conclusion: We expect that program promoting intention to exercise performance is used in nursing practice for the elderly with DJDs are needed to manage lifestyle.

• 대한전기학회논문지:전력기술부문A
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• 제48권1호
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• pp.31-35
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• 1999

In this paper, we consider the robust pole assignment and the upper bound of quadratic cost function for the linear systems with time-varying uncertainy. The considered uncertainties are both the norm bounded unstructured case and the structured case that has the matrix polytope type uncertain structure. We derve conditions that guarantee the robust pole assignment inside a disk in the L.H.P. and the robust stability. Also, we derive the upper bound of quadratic cost for thil pole assigned systems. Finally, we show the usefulness of our results by an example.

• 대한수학회논문집
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• 제37권2호
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• pp.455-472
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• 2022

For j = 0, 1, 2,…, k - 1; k ≥ 2; and - 1 ≤ B < A ≤ 1, we have introduced the functions classes denoted by ST_[j,k](A, B) and K_[j,k](A, B), respectively, called the generalized (j, k)-symmetric starlike and convex functions. We first proved the sharp bounds on |f(z)| and |f'(z)|. Various radii related problems, such as radius of (j, k)-symmetric starlikeness, convexity, strongly starlikeness and parabolic starlikeness are determined. The quantity |a²₃ - a₅|, which provide the initial bound on Zalcman functional is obtained for the functions in the family ST_[j,k]. Furthermore, the sharp pre-Schwarzian norm is also established for the case when f is a member of K_[j,k](α) for all 0 ≤ α < 1.

• 대한수학회지
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• 제60권5호
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• pp.1057-1072
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• 2023

Let 𝜑 : ℝⁿ × [0, ∞) → [0, ∞) be a growth function and H^𝜑(ℝⁿ) the Musielak-Orlicz Hardy space defined via the non-tangential grand maximal function. A general summability method, the so-called 𝜃-summability is considered for multi-dimensional Fourier transforms in H^𝜑(ℝⁿ). Precisely, with some assumptions on 𝜃, the authors first prove that the maximal operator of the 𝜃-means is bounded from H^𝜑(ℝⁿ) to L^𝜑(ℝⁿ). As consequences, some norm and almost everywhere convergence results of the 𝜃-means, which generalizes the well-known Lebesgue's theorem, are then obtained. Finally, the corresponding conclusions of some specific summability methods, such as Bochner-Riesz, Weierstrass and Picard-Bessel summations, are also presented.

• 한국멀티미디어학회논문지
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• 제13권3호
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• pp.378-391
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• 2010

본 논문에서는 손가락 면의 영상으로 개인 식별이 가능한지를 실험하고 그 결과를 제시하였다. 이를 위하여 구배치(gradient)를 산출할 수 있는 오퍼레이터인 FFG 마스크(Facet Function Gradient mask)를 사용하고, F-알고리즘이라 명명한 새로운 방법으로 매칭 처리를 하였다. 이 알고리즘에서 손가락 면의 영상을 일정한 크기의 부영역(subregion)으로 나누고, 부영역은 다시 일정한 크기의 패치(patch)들로 나눈다. 각 패치에 같은 크기의 FFG 마스크들을 컨벌루션시키고, 마스크 별로 하나의 수치를 얻는다. 이들 수치를 특징매트릭스(feature matrix)로 삼고, norm에 의하여 동일인 여부를 판정한다. 두 개의 손 영상이 동일인의 것인 경우와 그렇지 않은 경우에 FFG 컨벌루션 수치 차 제곱 총화의 분포를 관찰한 결과 뚜렷한 차별성을 보였다. 이것은 손가락 면 영상의 식별 능력을 입증하는 결과이다. 100명의 손 영상을 5벌씩 촬영한 500장의 영상을 F-알고리즘에 의하여 실험한 결과 95.0%의 개인 식별률을 얻었다. 이러한 식별 능력과 식별률에 비추어 손가락 면(finger face)은 다른 biometric들과 대등한 수준으로 개인 식별을 위한 biometrics의 하나로 손색이 없음을 말할 수 있다

• Structural Engineering and Mechanics
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• 제62권1호
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• pp.55-64
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• 2017

An effective design approach for Multiple Tuned Mass Dampers (MTMDs) in pedestrian bridges was proposed by utilizing the transfer function to obtain each TMD's optimum stiffness and damping. A systematic simulation of pedestrian excitations was described. The motion equation of a typical MTMD system attached to a Multi-degree-of-freedom (MDOF) system was presented, and the transfer function from the input pedestrian excitations to the output acceleration responses was defined. By solving the minimum norm of the transfer function, the parameters of the MTMD which resulted in the minimum overall responses can be obtained. Two applications of lightly damped pedestrian bridges attached with MTMD showed that MTMDs designed through this method can significantly reduce the structural responses when subjected to pedestrian excitations, and the vibration control effects were better than the MTMD when it was considered as being composed of equal number and mass ratios of TMDs designed by classical Den Hartog method.

• 정보과학회지
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• 제1권1호
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• pp.72-74
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• 1983

Traditionally, polynomials have been used to approximte functions with prescribed values at a number of points(called the knots) on a given interal on the real line. The method of splines recently developed is more flexible. It approximates a function in a piece-wise fashion, by means of a different polynomial in each subinterval. The cubic spline gas ets origins in beam theory. It possessed continuous first and second deriatives at the knots and is characterised by a minimum curvature property which es rdlated to the physical feature of minimum potential energy of the supported beam. Translated into mathematical terms, this means that between successive knots the approximation yields a third-order polynomial sith its first derivatives continuous at the knots. The minimum curvature property holds good for each subinterval as well as for the whole region of approximation This means that the integral of the square of the second derivative over the entire interval, and also over each subinterval, es to be minimized. Thus, the task of determining the spline lffers itself as a textbook problem in discrete computer programming, since the integral of ghe square of the second derivative can be obviously recognized as the criterion function whicg gas to be minimized. Starting with the initial value of the function and assuming an initial solpe of the curve, the minimum norm property of the curvature makes sequential decision of the slope at successive knots (points) feasible. It is the aim of this paper to derive the cubic spline by the methods of computer programming and show that the results which is computed the all the alues in each subinterval of the spline approximations.

• 전자공학회논문지CI
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• 제43권4호
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• pp.88-102
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• 2006

멀티미디어 정보 검색에서 멀티미디어 데이터는 고차원 공간상의 벡터로 표현된다. 이러한 특정 벡터를 효율적으로 검색하기 위하여 다양한 색인 기법이 제안되어 왔다. 그러나 특정 벡터의 차원이 증가하면서 색인 기법의 효율성이 급격히 떨어지는 차원의 저주 문제가 발생한다. 차원의 저주 문제를 해결하기 위하여 색인하기 이전에 원 특정 벡터를 저차원 공간상의 벡터로 사상하는 차원 축소 기법이 제안된 바 있다. 본 연구에서는 벡터의 놈과 각도 성분을 이용하여 유클리드 거리를 근사하는 함수를 기반으로 하는 새로운 차원 축소 기법을 제안한다. 먼저, 유클리드 거리 근사를 위하여 추정된 각도의 오차의 발생 원인을 분석하고 이 오차를 줄이기 위한 기본 방향을 제시한다. 또한, 고차원 특정 벡터를 다수의 특징 서브 벡터들의 집합으로 분리하고 각 특징 서브 벡터로부터 놈과 각도 성분을 근사하여 차원을 축소하는 새로운 기법을 제안한다. 각도 성분을 정확하게 근사하기 위해서는 올바른 기준 벡터의 설정이 필수적이다. 본 연구에서는 최적 기준 벡터의 조건을 제시하고, Levenberg-Marquardt 알고리즘을 이용하여 기준 벡터를 선정하는 방법을 제안한다. 또한, 축소된 저차원 공간상의 벡터틀을 위한 새로운 거리 함수를 정의하고, 이 거리 함수가 유클리드 거리 함수의 하한 함수가 됨을 이론적으로 증명한다. 이는 제안된 기법이 착오 기각의 발생을 허용하지 않으면서 효과적으로 차원을 줄일 수 있음을 의미하는 것이다. 끝으로, 다양한 실험에 의한 성능 평가를 통하여 제안하는 방법의 우수성을 규명한다.