Journal of Operational Research in its Applications
Year:2008 | Volume:5 | Issue:16|Papers Count:8

This paper applies the homotopy perturbation method (HPM) to find the exact solution of Poisson equation with the Dirichlet and Neumann boundary conditions. To illustrate the simplicity and reliability of the method, two examples are provided. The results obtained reveal that the method is capable and easy to apply.

In this paper first we are going to give a brief history of development of the fuzzy entropy. Finally new measures of entropy for fuzzy sets in continuous reference set are introduced. Also we compare discrete and continuous via an example.

A graph G with no isolated vertex is total domination vertex critical if for any vertex u of G that is not adjacent to vertex of degree one, the total domination number G-u of is less than the total domination number of G. We call these graphs total domination critical or just gt-critical. If such a graph G has total domination number k, we call k- gt -critical. We study some results on the characterization of total domination critical graphs of order D(G)+4.

In this paper, we have used the iterative method suggested by Daftardar-Gejji and Jafari for solving system of nonlinear equations [4]. In the implementation of this new method, one does not need the computation of the derivative of the so-called Adomian polynomials. The method is quite efficient and is practically well suited for use in these problems. Some examples have been presented.

In this paper, we introduce the revenue efficiency interval of a DMU. The revenue interval DEA model has been formulated to obtain an efficiency interval in which the lower bound and upper bound of this interval are respectively, the efficiency obtained from pessimistic and optimistic viewpoints.

The past decade has witnessed substantial progress towards the application of low-rate speech coders to civilian and military communications as well as computer- related voice applications. Central to this progress has been the development of new speech coders capable of producing high- quality speech at low data rates. Most of these coders incorporate mechanisms to: represent the spectral properties of speech, provide for speech waveform matching, and "optimize" the coder's performance for the human ear. A number of these coders have already been adopted in national and international cellular telephony standards. In mobile communication systems, service providers are continuously met with the challenge of accommodating more users within a limited allocated bandwidth. For this reason, manufactures and service providers are continuously in search of low bit-rate speech coders that deliver toll- quality speech. The objective of this project is to compare three commonly used algorithms in wireless communication systems: ADPCM, CELP and VSELP. The project report starts with the description of these speech coders. Then we present our implementation results and finally give concluding remarks followed by comments on future research in this area.

Linear electric motors can drive a linear motion load without intermediate gears, screws or crank shafts. A linear synchronous motor (LSM) is a linear motor in which the mechanical motion is in synchronism with the magnetic field, i.e. the mechanical speed is the same as the speed of traveling magnetic field. In this paper, we obtained the electromagnetic thrust developed by a salient-pole LSM.

Let R  be a Z-graded commutative ring with identity. Several characterizations of graded distributive modules will be investigate.