• Journal of applied mathematics & informatics
• /
• 제31권1_2호
• /
• pp.55-63
• /
• 2013

In this paper, a general technique is proposed for solving a system of fourth-order boundary value problems. The solution is given in the form of series and its approximate solution is obtained by truncating the series. Advantages of the method are that the representation of exact solution is obtained in a new reproducing kernel Hilbert space and accuracy of numerical computation is higher. Numerical results show that the method employed in the paper is valid. Numerical evidence is presented to show the applicability and superiority of the new method.

• 국제학술발표논문집
• /
• The 6th International Conference on Construction Engineering and Project Management
• /
• pp.109-110
• /
• 2015

This paper presents a computational method that identifies an exact set of optimal overlap rates between critical activities to meet job site specific needs by using rework cost-slope. The procedures to compute the exact solution are provided in peudocode algorithm. The method is coded into Exact Concurrent Construction Scheduling system that allows practitioners to make more informed decision in accordance with the site-specific condition involved in the overlapping of critical activities. Test cases verify the validity of the computational method and the usability of the system.

• 한국경영과학회지
• /
• 제30권1호
• /
• pp.161-176
• /
• 2005

In a situation that ordinal preferences on multiattribute weights are captured, we present two solution approaches: an exact approach and an approximate method. The former, an exact solution approach via interaction with a decision-maker, pursues the progressive reduction of a set of non-dominated alternatives by narrowing down the feasible attribute weights region. Subsequent interactive questions and responses, however, sometimes may not guarantee the best alternative or a complete rank order of a set of alternatives that the decision-maker desires to have. Approximate solution approaches, on the other hand, can be divided into three categories including surrogate weights methods, dominance value-based decision rules, and three classical decision rules. Their efficacies are evaluated in terms of choice accuracy via a simulation analysis. The simulation results indicate that a proposed hybrid approach, intended to combine an exact solution approach through interaction and a dominance value-based approach, is recommendable for aiding a decision making in a case that a final choice is seldom made at single step under attribute weights that are imprecisely specified beyond ordinal descriptions.

• 한국경영과학회지
• /
• 제20권1호
• /
• pp.147-158
• /
• 1995

In this paper a face optimization algorithm is developed for solving the problem (P) of optimizing a linear function over the set of efficient solution of a bicriterion linear program. We show that problem (P) can arise in a variety of practical situations. Since the efficient set is in general a nonoconvex set, problem (P) can be classified as a global optimization problem. The algorithm for solving problem (P) is guaranteed to find an exact optimal or almost exact optimal solution for the problem in a finite number of iterations. The algorithm can be easily implemented using only linear programming method.

• Korean Journal of Mathematics
• /
• 제21권3호
• /
• pp.293-304
• /
• 2013

In this paper we analyze an error estimator for the lowest-order triangular Raviart-Thomas mixed finite element which is based on solution of local problems for the error. This estimator was proposed in [Alonso, Error estimators for a mixed method, Numer. Math. 74 (1996), 385{395] and has a similar concept to that of Bank and Weiser. We show that it is asymptotically exact for the Poisson equation if the underlying triangulations are uniform and the exact solution is regular enough.

• 호남수학학술지
• /
• 제30권4호
• /
• pp.631-635
• /
• 2008

In this paper we discuss on the formal linearization and exact solution of Klein-Gordon's equation (1) $u_{tt}-au_{xx}+bu-cu^3=0 a,b,c{\in}R^+$ So that we know an efficient method for constructing of particular solutions of some nonlinear partial differential equations is introduced.

• 소음진동
• /
• 제9권5호
• /
• pp.966-974
• /
• 1999

This paper introduces modeling and its modal analysis procedure for exact and closed form solution of in-plane vibrations of general Timoshenko frame structures using exact dynamic element method(EDEM). The derivation procedure of the exact system dynamic matrices for Timoshenko beam frames is described. A new modal analysis procedure is also proposed since the conventional modal analysis schemes are not adequate for the proposed, exact system dynamic matrix. The proposed method provides exact modal parameters as well as all kinds of closed form solutions for general frame structures. Two numerical examples are presented for validating and illustrating the proposed method. The numerical study proves that the proposed method is useful for dynamic analysis of frame structures.

• 설비공학논문집
• /
• 제7권1호
• /
• pp.42-51
• /
• 1995

In order to establish a theoretical basis for the analyses of transient behaviors in stratified thermal storage tanks, analytical approaches to an improved one-dimensional model are made. In the present model the storage tank is treated as a finite region with an adiabatic tank exit, whereas it has been considered as a simple semi-infinite region previously. Application of the Laplace transformation and the Inversion theorem to the governing equations makes it possible to obtain an exact infinite-series solution, which is convergent only at sufficiently large time. Accordingly a complementary solution which is available for short times, i.e., the time range of this study is sought by an approximate method. The approximate solution which is rigorously validated through the examination of neglected terms in the solution procedure agrees quite well with the exact one. Moreover, it is simpler to use and more convenient to interpret the physical meaning of the solution. Comparison of the present solution with the previous ones shows relatively large difference near the tank bottom, which results from the more realistic boundary condition adopted in the present model. Some representative results by the approximate solution including effects of the Peclet number on temperature distrbutions are illustrated to show the utility of this study. In consequence, it is expected that the present results based on the improved model replace the foregoing ones as a new theoretical reference for studies of thermal stratification fields.

• Steel and Composite Structures
• /
• 제25권2호
• /
• pp.127-139
• /
• 2017

In this paper, an exact analytical solution for simply supported sandwich plate which considers the permeation effect of adhesives is presented. The permeation layer is described as functionally graded material (FGM), the elastic modulus of which is assumed to be graded along the thickness following the exponential law. Based on the exact three-dimensional (3-D) elasticity theory, the solution of stresses and displacements for each layer is derived. By means of the recursive matrix method, the solution can be efficiently obtained for plates with many layers. The present solution obtained can be used as a benchmark to access other simplified solutions. The comparison study indicates that the finite element (FE) solution is close to the present one when the FGM layer in the FE model is divided into a series of homogeneous layers. However, the present method is more efficient than the FE method, with which the mesh division and computation are time-consuming. Moreover, the solution based on Kirchhoff-Love plate theory is greatly different from the present solution for thick plates. The influence of the thickness of the permeation layer on the stress and displacement fields of the sandwich plate is discussed in detail. It is indicated that the permeation layer can effectively relieve the discontinuity stress at the interface.

• 한국지진공학회:학술대회논문집
• /
• 한국지진공학회 2000년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2000
• /
• pp.143-150
• /
• 2000

A physical lumped parameter model is proposed for the time domain analysis of dam-reservoir system. The exact solution of transmitting boundary is derived for a semi-infinite 2-D reservoir of constant depth. The characteristics of the solution are examined in both frequency and the domains. Mass and damping coefficient are obtained from asymptotic behavior of the frequency domain solution. Further refinement to the lumped model is made by approximating the kernel function of the convolution integral in the exact solution. Finally a new physical lumped parameter model is proposed that consists of two masses, a spring and two dampers for each mode. It is demonstrated that new lumped parameter model of transmitting boundary can give excellent results.