Existential second-order logic (ESO) and monadic second-order logic (MSO) have attracted much interest in logic and computer science. ESO is a much more expressive logic over word structures than MSO. However, little was known about the relationship between MSO and syntactic fragments of ESO. We shed light on this issue by completely characterizing this relationship for the prefix classes of ES...

Over the last ten years, robustness of schemes has raised an increasing interest among the CFD community. The objective of this article is to solve the quasi-one-dimensional compressible flow inside a “Shubin nozzle” and to investigate Bean-Warming and flux vector splitting methods for numerical solution of compressible flows. Two different conditions have been considered: first, there is a sup...

The first-order schemes used for discretisation of the convective terms are straightforward and easy to use, with the drawback of introducing numerical diffusion. Application of the secondorder schemes, such as QUICK scheme, is a treatment to reduce the numerical diffusion, but increasing convergence oscillation is unavoidable. The technique used in this study is a compromise between the above-...

this study focuses on the optimization of the plane structure. sequential quadratic programming (sqp) will be utilized, which is one of the most efficient methods for solving nonlinearly constrained optimization problems. a new formulation for the second order sensitivity analysis of the two-dimensional finite element will be developed. all the second order required derivatives will be calculat...

In this paper, using the hyperbolic uniform spline of order 4 we develop the classes of methods for the numerical solution of second order boundary value problems (2VBP) with Dirichlet, Neumann and Cauchy types boundary conditions. The second derivativeis approximated by the three-point central difference scheme. The approximate results, obtained by the proposed method, confirm theconvergence o...