this paper presents an exact analytical solution for two-dimensional conductive heat transfer in spherical composite pressure vessels .the vessels are in spherical shape and fibers are winded in circumferential direction. the analytical solution is obtained under the general boundary conditions which consist of convection, conduction and radiation inside/outside of vessel. the heat transfer equ...

In this paper we present MD, a logical model for OLAP systems, and show how it can be used in the design of multidimensional databases. Unlike other models for multidimensional databases, MD is independent of any speci c implementation (relational or proprietary multidimensional) and as such it provides a clear separation between practical and conceptual aspects. In this framework, we present a...

The multidimensional (MD) modeling, which is the foundation of data warehouses (DWs), MD databases, and On-Line Analytical Processing (OLAP) applications, is based on several properties different from those in traditional database modeling. In the past few years, there have been some proposals, providing their own formal and graphical notations, for representing the main MD properties at the co...

Current SQL aggregation functions have evident limitations for computing percentages, for which this paper proposes two SQL aggregation functions. The two novel aggregation functions are easy to use, which have wide applicability and can be efficiently evaluated. They may be used as a framework to study percentage queries and to generate efficient SQL code. Experiments compare our proposed perc...

In this paper we present our approach for extending the OLAP model to include treatment of value uncertainty as part of a multidimensional model inhabited by flexible data and non-rigid hierarchical structures of organisation. A new multidimensional-cubic model named as the IF-Cube is introduced which is able to operate over data with imprecision either in the facts or in the dimensional hierar...

We consider the chemotaxis problem for a one-dimensional system. To analyze the interaction of bacteria and attractant we use a modified KellerSegel model which accounts attractant absorption. To describe the system we use the chemotaxis sensitivity function, which characterizes nonuniformity of bacteria distribution. In particular, we investigate how the chemotaxis sensitivity function depends...