To use pressure transient test data in computerised methods for integrated reservoir charcterisation numerical simulations of the well tests are typically required. Numerical artifacts occurring in the simulation must be avoided as much as possible so that they do not adversely affect the reservoir characterisation. This work explores the advantages of a hybrid boundary element method known as ...

A finite-difference method for integro-differential equations arising from Lévy driven asset processes in finance is discussed. The equations are discretized in space by the collocation method and in time by an explicit backward differentiation formula. The discretization is shown to be second-order accurate independently of the degree of the singularity in the Lévy measure. The singularity is ...

A singularity handling method is proposed in this paper. It is done by introducing virtual redundant joints into the Jacobian matrix to maintain the rank of the Jacobian matrix when singularity occurs. These additional joints do not exist physically. Therefore, although mathematically stable, the manipulator still can not perform tasks in the degenerate direction(s). This method is comparativel...

This paper deals with the singularities of kinematically redundant manipulators in terms of determining the singularity manifolds in configuration space, and detecting/handling singular configurations in a local kinematic planning environment. Using the example of a specific manipulator with 8 degrees of freedom, a systematic method is presented which is generally applicable to the given class ...

We consider the linear system arising from discretization of the pressure Poisson equation with Neumann boundary conditions, derived from bubbly flow problems. In the literature, preconditioned Krylov iterative solvers are proposed, but they often suffer from slow convergence for relatively large and complex problems. We extend these traditional solvers with the so-called deflation technique, t...

In engineering applications, the singularity, and the forward and inverse displacement of spatial parallel manipulators have received a great deal of attention. This paper presents a new simple but effective methodology to investigate these problems based on the analysis of the degree of freedom (DoF) of the spatial parallel manipulator. Through numerical method, the singularity and the forward...

A recent paper [l] is generalized to a case where the spatial region is taken in @. The region is assumed to be a thin body, such as a panel on the wing or fuselage of an aerospace vehicle. The traditional has well as hp-finite element methods are applied to the surface defined in the z y variables, while, through the thickness, the technique of the p-element is employed. Time and spatial discr...

The stability and accuracy of a standard finite element method (FEM) and a new streamline diffusion finite element method (SDFEM) are studied in this paper for a one dimensional singularly perturbed connvection-diffusion problem discretized on arbitrary grids. Both schemes are proven to produce stable and accurate approximations provided that the underlying grid is properly adapted to capture t...

The Hamilton-Jacobi equation for the string cosmology is solved using the gradient expansion method. The zeroth order solution is taken to be the standard pre-big bang model and the second order solution is found for the dilaton and the three-metric. It indicates that corrections generated by inhomogeneities of the seed metric are suppressed near the singularity and are growing towards the asym...

We investigate the free-edge stresses in anisotropic bimaterials through the use of the free-edge stress intensity factor, Kf . This requires a determination of the singularity order at the free-surface as well as a calculation of the near-field stresses. We determine the order of the singularity for arbitrary free-surface orientation of the upper material using an eigenvalue analysis for aniso...