• 대한수학회지
• /
• 제45권2호
• /
• pp.455-466
• /
• 2008

Current studies on products of analytic functionals have been based on applying convolution products in D' and the Fourier exchange formula. There are very few results directly computed from the ultradistribution space Z'. The goal of this paper is to introduce a definition for the product of analytic functionals and construct a new multiplier space $F(N_m)$ for $\delta^{(m)}(s)$ in a one or multiple dimension space, where Nm may contain functions without compact support. Several examples of the products are presented using the Cauchy integral formula and the multiplier space, including the fractional derivative of the delta function $\delta^{(\alpha)}(s)$ for $\alpha>0$.

• 물과 미래
• /
• 제25권4호
• /
• pp.97-107
• /
• 1992

본 연구의 목적은 강우에 따른 하천에서의 직접유출에 대한 해석을 위하여 Horton과 Strahler의 하천분석 및 차수의 법칙에 따라 지형도로부터 얻은 지형학적 자료와 토양, 수리, 및 기후학적 자료를 가지고 Interactive Program을 사용하여 미계측소유역의 유출량과 단위도를 산정하는 것이다. 이 모델은 각 지점의 유하시간을 Laplace 변환과 확률밀도함수의 집적된 겨로가로 이용되었다. 이 Program을 이요하여 금강수계내의 보청천 대표유역내의 최상류지점인 산성지점에 대하여 직접유출량과 Peak 시간에 있어서 홍수량을 산정하였다.

• 한국산업융합학회 논문집
• /
• 제12권3호
• /
• pp.149-155
• /
• 2009

A new finite element equation is derived by applying quadratic and cubic time integration scheme to the variational formulation in time-integral for the analysis of the transient elastodynamic problems to increase the numerical accuracy and stability. Emphasis is focused on methodology for cubic time integration scheme procedure which are never presented before. In this semidiscrete approximations of the field variables, the time axis is divided equally and quadratic and cubic time variation is assumed in those intervals, and space is approximated by the usual finite element discretization technique. It is found that unconditionally stable numerical results are obtained in case of the cubic time variation. Some numerical examples are given to show the versatility of the presented formulation.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2014년도 추계학술대회 논문집
• /
• pp.298-299
• /
• 2014

The solution of transient response of complex stiffness system was obtained using a green function of this system. To derive the green function, governing equation of this systems was expressed in Steady Space and solved by the diagonalization. The solution of this system are written as a convolution integral form. The result that are calculated by the numerical integration process for transient responses was showed properly.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 하계학술대회 논문집 A
• /
• pp.530-532
• /
• 2001

This paper illustrates a method for evaluating nodal probabilistic production cost using the CMELDC. A new method for constructing CMELDC(the equivalent load duration curves of composite power system) was developed by authors. The CMELDC can be obtained by convolution integral processing between the probability distribution functions of the fictitious generators outage capacity and the load duration curves at each load point. Monte Carlo Methods are applied for the construction of CMELDC on this study. And IEEE-RTS 24 buses model is used as our case study with satisfactory results.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 하계학술대회 논문집 A
• /
• pp.206-209
• /
• 2001

This paper illustrates a new method for reliability evaluation at load points in a composite power system. The algorithm includes uncertainties of generators and transmission lines as well as main transformers at substations. The CMELDC based on the new effective load model at HLII has been developed also. The CMELDC can be obtain from convolution integral processing of the outage capacity probabilistic distribution function of the fictitious generator and the original load duration curve given at the load point. The CMELDC based on the new model at HLII will extend the application areas of nodal probabilistic production cost simulation, outage cost assessment and reliability evaluation etc. at load points. The characteristics and effectiveness of this new model are illustrated by a case study of a small test system.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 1997년도 가을 학술발표회 논문집
• /
• pp.42-49
• /
• 1997

In this paper, the method for soil-structure interaction analyses in the time domain is proposed. The far field soil region which is the outside of the artificial boundary is modeled by using explicit frequency-dependent two dimensional infinite elements which can include multiple wave components propagating into the unbounded medium. Since the dynamic stiffness matrix of the far field soil region using the proposed infinite elements is obtained explicitly in terms of exciting frequencies and constants in the frequency domain, the matrix can be easily transformed into the displacement unit-impulse response matrix, which corresponds to a convolution integral of it in the time domain. To verify the proposed method for soil-structure interaction analyses in the time domain, the displacement responses due to an impulse load on the surface of a soil layer with the rigid bed rock are compared with those obtained by the method in the frequency domain and those by models with extend finite element meshes. Good agreements have been found between them.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2001년도 춘계학술대회논문집B
• /
• pp.540-545
• /
• 2001

In this paper dynamic responses of an engine, which is supported by hydraulic mount, to throttle tip-in/tip out are analyzed. Because the hydraulic mounts have non-linearity which the characteristics of stiffness and damping vary with frequencies, it is difficult to analyze the dynamic behavior of an engine using general integral algorithms. Convolution integrals and relationships between unit impulse response functions and frequency response functions are therefore used to simulate the transient behavior of an engine indirectly. In time domain, impulse response functions are calculated by two-side discrete inverse Fourier transform of frequency response function achieved by Laplace transform of equations of motion. Considering the fact that the shapes of behavior of an engine simulated by the proposed method are in good agreement with test results, it is confirmed that the proposed method is very effective for the analysis of transient response to throttle tip-in/out of an engine with hydraulic mounts.

• 한국의학물리학회지:의학물리
• /
• 제3권2호
• /
• pp.67-81
• /
• 1992

방사선영상의 충실도를 저하시키는 것에는 여러가지 물리적현상이 있다. 가장 보편적인 저하타입은 해상력의 상실과 노이즈의 증가이다. 본 논문은 해상력과 해상력에 미치는 인자, 그리고 그 인자들의 특성을 다룬다. 영상을 흐리게 하는 일반적인 현상때문에 생기는 해상력 상실을, 일차원및 이차원 신호를 대상으로 그림과 수학으로 설명한다. 점분산함수, 선분산함수, 컨볼루션 적분함수및 모둘전달함수등을 논의한다. 또한 퓨리에 변환을 사용해서 주파수영역의 연산개념을 언급한다.

• 대한기계학회논문집
• /
• 제17권11호
• /
• pp.2684-2693
• /
• 1993

The free vibration and dynamic response of cross-ply for CFRP and GFRP laminated circular cylindrical shells under dynamic loadings are investigated by using the first-order shear deformation shell theory. The modal analysis technique is used to develop the analytical solutions of simply supported cylindrical shells under dynamic load. The analysis is based on an expansion of the loads, displacements and rotations in a double Fourier series which satisfies the and boundary conditions of simply support. Analytical solution is assumed to be separable into a function of time and a function of position. In this paper, the considered load forces are step pulse, sine pulse, triangular(1, 2, 3) pulse and exponential pulse. The solution for a given loading pulse can be found by involving the convolution integral. The results show that the dynamic response are governed primarily by the natural period of the structure.