mathematical model

Selecting suitable suppliers and assigning orders to them, is one of the most important strategic supply chain management activities. Therefore, first, in this research, a mathematical model for choosing the supplier in the supply chain in the framework of the operational research methods was proposed. Linear programming model with consideration of purchase costs and transportation costs with the meta-heuristic bee algorithm approach using MATLAB software was solved and analyzed. Therefore, the research method is applied in terms of purpose, and in terms of method is a descriptive mathematical type that was implemented in the form of a library and field studies. Information gathering tools, such as documentation tools, interviews with experts and production managers were used in relation to production. According to the nature of the research, which is modeling and solving by the algorithm, to determine the sample size were selected by cluster sampling method and random sampling method. Then to validate the mathematical model, lingo and Winqsb software was used, the solution obtained by both software, which is the optimal answer and optimal objective function, indicates the validity of the mathematical model.

Security is one of the most important aspects of data transmission. To provide controlled access to the network, user authorization and authentication are often used with the help of an AAA server. RADIUS servers provide users with access to data, user authentication, and configuration information. When designing networks with such access control method implementation, it is necessary to understand how the characteristics of the communication channel affect the switching time of IP-TV channels, and therefore the overall quality of IP-TV services. The principles of the main protocols for IP-TV using a RADIUS server are described. The main parameters of the communication channel were identified. The mathematical model and the graphs demonstrate how IP-TV service access time depends on telecommunication channel parameters. The results of a practical experiment are presented to prove the formed mathematical model. The results of a practical experiment and theoretical calculation are compared.