Theory of Approximation and Applications
Volume:3 Issue: 2, Summer and Autumn 2007

Nowadays in the current industrial world, it is very important to use the time and the resources and to respond the market demands timely and correctly, therefore it will reveal the importance and the necessity of optimizing the production based on the market demand, considering the products with high added value. Regarding this fact that the steel industry is one of the basic industries and has a great influence upon the other industries, its productivity can affect upon itself as well as the other industries. The scope of this study is Isfahan Steel Corporation which is considered as one of the greatest plants throughout the country manufacturing steel products such as iron beam. Thus in this study, the corresponding documents and proofs were examined to optimize the beam products of Isfahan Steel Corporation based upon the market demand and increased value, and considering the records, opinions of production and sale experts, customers and suppliers, a questionnaire was prepared to estimate the types of beam and distributed among customers and suppliers and analyzed. Then, the added value of beams was calculated and finally, the amount of beam products was calculated based on estimated market demand using the model ARIMA

In this paper a method for solving fuzzy linear system with crisp solution is considered. We consider the method in special case when the coefficient matrix and the right hand side column are trapezoidal symmetric fuzzy numbers. The method in detail is discussed and illustrated by solving some examples.

In this paper, we comparatively study some of recently developed analytical techniques applied to the quadratic Riccati differential equation. Then we propose a new application of the homotopy perturbation method for solving the aforementioned equation. This application, elegantly, results in the Taylor’s expansion of the exact solution to the problem.

The role of the non-Archimedean number  in DEA models is clarified. If the non-Archimedean number  is selected unsuitable then the multiplier (envelopment) form of DEA models may be infeasible (unbounded). This research propose an assurance interval for non-Archimedean number  for BCC and CCR models.