Application development and e-learning services in the context of communication networks and information along with qualitative and quantitative improvements of activities and services can expand some of threats which emergence in the networks of this infrastructure of telecommunications. Consequently, this is an inevitable necessity attention to accuracy and efficiency payment issues and security concerns to managers and decision makers. Based on other researches and effective experiences in the field of e-learning security, this research attempts to define a logical structure to security contents in this field. We have presented a three-dimensional model for security issues and requirements of e-learning, based on the findings of research. Actuarial three-dimensional model are infrastructure-oriented viewpoint; service-oriented viewpoint and customer-oriented viewpoint. Each of these three dimensions in this model has described in the form of model with two fields: e-learning issues and security of e-learning issues.

This paper models the process of ordered product design decision making. The problem is formulated by introducing the notion of Quality Loss to quantify the loss of design freedom incurred by the decision makers in the later stages of a cross-functional decision process. In this context, the optimal order is the decision order with the lowest quality loss, whose characterization is one of the contributions of this paper. In this paper, we present a novel decision support system for order in a Make-to-Stock or Make-to-Order production environment. The proposed decision support system is comprised of six steps. The customers are prioritized based on a new method. In this paper, the idea of the algorithm “Knapsack” is used to prioritize customers. Finally, numerical experiments are conducted to show the tractability of the applied mathematical programming model.

Supplier selection, inventory management and optimal lot sizing has been one of the most important issues in many industries especially in production planning issues associated with texture industry. The proposed model of this paper first introduces an algorithm to choose the best supplier and it determines the optimal lot size using discount strategy. The proposed model of this paper considers different influencing factors such as location, quality of materials, cost, and mutual trust for supplier selection, determines their relative importance weights and then a discounting method is used to determine the ordering lot-size. The preliminary results indicate that the proposed model of this paper can be implemented in texture industry, very efficiently since the ordering discount policy is not sensitive to changes on inventory holding and setup expenditures.