The Research And Calculation Of Optimization Models In VoD System

The VoD System handles mainly multimedia data, while the multimedia data usually needs much more disk space and bandwidth. In large VoD System, it's not easy to manage efficiently network bandwidth. So, it can hardly satisfy the need of the customers. For the sake of resolving these problems, reducing the backbone network bandwidth consumption becomes the focus problem of VoD System. In order to solve this problem, we build up three mathematical models and get a linear programming problem, a multi-objective programming problem and a non-linear programming problem. Furthermore, we show a iterative algorithm to solve the multi-objective programming problem. And we show a greedy algorithm to solve the non-linear programming problem.The main results obtained in this dissertation may be summarized as follows:In chapter 2, in proxy-based VoD System, we build up a mathematical model and get a linear programming problem. And the objective function is the backbone network bandwidth consumption and the main constraint condition is the proxy caching space. Finally, we show methods to solve this problem.In chapter 3, in proxy-based VoD System, we build up a mathematical model and get a multi-objective programming problem. Finally, we show a iterative algorithm to solve this problem.In chapter 4, in proxy-based VoD System with patching strategy, we build up a mathematical model and get a non-linear programming problem. And the objective function is the backbone network bandwidth consumption and the main constraint condition is the proxy caching space and patching window. Finally, we show a greedy algorithm to solve this problem.