Sharif Digital Repository

Many real-world communication systems such as Internet, online social networks, and brain networks can be modeled as a complex network of interacting dynamical nodes. These networks have non-trivial topological features, i.e., features that do not occur in simple networks such as lattices or random networks. The tremendous growth of Internet and its applications in recent years has resulted in creation of large-scale complex networks involving tens or hundreds of millions of nodes and links. Thus, it may be impossible or costly to obtain a complete picture of these large networks, and sampling methods are essential for practical estimation of network properties. Therefore, in this thesis, we... 

Knowing the shape and type of the breakdown of a system or the system components, for a maintenance manager or maintenance engineer is significantly important. It is also important that the existing information concerning the system performance predict and prevent a sudden failure to be probably taken place. Maintenance has gained in importance as a support function for ensuring equipment availability, quality products, on-time deliveries, and plant safety. Cost effectiveness and accuracy are two basic criteria for good maintenance. Many studies in the area of equipment maintenance, replacement, and reliability require that the failure characteristic of a component to be estimated from... 

Many congestion control protocols proposed so far to alleviate the problems encountered by TCP protocol in high-speed networks and wireless links have to estimate the parameters of the network. For example, the TCP WESTWOOD congestion window is adjusted based on available bandwidth estimation, or TCP Vegas detects the congestion status based on RTT (Round Trip Time) estimation, and XCP protocol operates according to network traffic load. In this paper, we proposed a novel estimation algorithm that is based on burst identification techniques in router. we show through analysis and simulation that during burst periods this method can estimate the congestion window size of the specific flow...