Abstract A fast approximation method to three dimensional equations in quasi-static uncoupled thermoelasticity is proposed. We approximate the density via Gaussian approximating functions introduced approximations. In this way action of integral operators on such presented a simple analytical form. If has separated representation, problem reduced computation one-dimensional integrals which admi...

The design approximation problem is a well known problem in stock cutting, where, in order to facilitate the optimization techniques used in the cutting process, it is required to approximate complex designs by simpler ones. Although there are algorithms available to solve this problem, they all suffer from an undesirable feature that they only produce one optimal solution to the problem, and d...

We present in this paper differential approximation results for    and    . We first show that the differential approximation ratio of the natural greedy algorithm for    is bounded below by 1.365/∆ and above by 4/(∆ + 1), where ∆ is the maximum set-cardinality in the   -instance. Next we study another approximation algorithm for   ...

In this paper, a comparison of weak-form Galerkin and least-squares finite element models of Timoshenko beam theory with the von Kármán strains is presented. Computational characteristics of the two models and the influence of the polynomial orders used on the relative accuracies of the two models are discussed. The degree of approximation functions used varied from linear to the 5th order. In ...

The Volterra delay integral equations have numerous applications in various branches of science, including biology, ecology, physics and modeling of engineering and natural sciences. In many cases, it is difficult to obtain analytical solutions of these equations. So, numerical methods as an efficient approximation method for solving Volterra delay integral equations are of interest to many res...

the spline collocation method  is employed to solve a system of linear and nonlinear fredholm and volterra integro-differential equations. the solutions are collocated by cubic b-spline and the integrand is approximated by the newton-cotes formula. we obtain the unique solution for linear and nonlinear system $(nn+3n)times(nn+3n)$ of integro-differential equations. this approximation reduces th...

In this paper, we study existence and approximation of solutions to some threepoint boundary value problems for fractional differential equations of the type Dq 0+u(t) + f(t, u(t)) = 0, t ∈ (0, 1), 1 < q < 2 u′(0) = 0, u(1) = ξu(η), where 0 < ξ, η ∈ (0, 1) and Dq 0+ is the fractional derivative in the sense of Caputo. For the existence of solution, we develop the method of upper and lower solut...

We present in this paper differential approximation results for min set cover and min weighted set cover. We first show that the differential approximation ratio of the natural greedy algorithm for min set cover is bounded below by 1.365/∆ and above by 4/(∆+1), where ∆ is the maximum set-cardinality in the min set cover-instance. Next we study another approximation algorithm for min set cover t...