Journal of Operational Research in its Applications
Year:2007 | Volume:3 | Issue:11|Papers Count:8

This paper provides an overview of elliptic curves and their use in cryptography. The focus of the paper is on the performance advantages obtained in the wireless environments by using elliptic curve cryptography instead of traditional cryptosystems such as RSA. Specific applications to secure messaging and identity-based encryption are also discussed.

System of linear equations is a problem that may be solved for solving many problems in various areas of applied sciences. Fuzzy methods constitute an important mathematical and computational tool for modeling real-world systems with uncertainties of parameters. The paper discusses fully fuzzy linear systems (shown as FFLS) using embedding approach to find its positive fuzzy number solutions. We investigate an n´n (FFLS) and replace the original n´n (FFLS) by a 2n´2n parametric linear system and finally, numerical examples are used to illustrate this approach.

The generalized eigenvalue problem AX=lBX has special properties when (A,B) is a symmetric and positive definite pair. We have recently developed three methods for computing a few smallest (largest) eigenvalues of a symmetric positive definite problem AX=lBX [2-3-4]. In this article we compared those methods by some numerical examples.

In this paper the p-graphs Matroeids and Hyper graphs and their Matrices are considered. Also it has been shown that a Matroeid and hyper graph are a p-graph and that there is a partial ordered relation between the nodes of the graphs.

Composite materials are used to design drive shafts when significant weight saving are sought or when traditional materials cannot be used. First, critical speeds of the shaft should lay outside of the range of operating speeds. The second constraint is that the shaft should not buckle under the maximum expected torque. We should also determine the stresses in each play and verify that failure does not occur by using a suitable criterion. Driveshaft design consists of selecting the shaft diameter and wall-thickness. With composites, the choice of fibers and fiber orientation are additional variables to be used for optimization. This thesis review theory necessary for designing composite driveshaft.

In this paper, we prove the completeness in the elliptic part of the domain of the system of eigenfunctions of the Gellerstedt problem for a degenerating equation of mixed type. Simultaneously, we consider the completeness of the system of eigenfunctions of the Tricomi and Neuman – Tricomi problems, which arise in studing the Gellerstedt problem.

In recent years, the computer graghics have improved highly. In this paper,  we present a special kind  of  the computer  graghics named  vectorial  graphics and point out  to  their  mathematical backgrounds  by using  the NURBS curves  and surfaces which are often unknown. Then, we propose the use of the presented mathematical formulas in the vectorial computer ghraghics.

Asset-liability management is a set of managerial tools, designed for banks in order to encounter the risks-those which result in a decrease in banks' profit and efficiency-which they face. Asset-liability management includes loan operation related costs, deposits and investment portfolio management and in another word it is a part of bank management and it can be counted as a structured and systematic process in balance sheets management. Actually Asset-liability management indicates the relation between risk and return. Therefore ALM discusses risk taking through creative guidelines in order to reach a desirable return and it always starts with analyzing the balance sheet and its internal and external elements. The purpose of this paper is the presentation of asset and liability management with the respect to goal programming model to achieve the ideal amount of liquidity and the combination of optimal assets and liabilities.