Mathematics of Information Technology and Complex Systems Complex Adaptive Networks for Computing and Communication (CANCCOM)


Project Highlights


Team Members

Partner Organizations







Project Highlights
    - Mobile and Wireless Computing

Barbeau and Kranakis (2003) have introduced a novel framework which core is a probabilistic model in which service discovery strategies can be modeled and evaluated in a uniform manner. They show how strategies can be represented, analyzed and evaluated through simulation. Three strategies were initially studied in detail: post-to-all/query-to-all, uniform memory less and incremental post-query. The Masters student Luo (2003) has pursued this work and implemented five strategies (greedy, incremental, uniform memoryless, with memory and conservative) over two different routing protocols (DSDV and DSR) in the NS2 simulation environment. The following approach has been devised by the Ph.D. student Hall to detect the start of the transient in radio frequency fingerprinting. A stream of samples is  decomposed into contiguous and non overlapping windows of equal lengths. The variance of the phase is calculated for each window. The differences in the variance of the phase are calculated as well from window to window, i.e. the first derivative of the phase. It appears that the differences are chaotic, until the start of the transient. Then at the start of the transient, the differences suddenly fall below a threshold. In other words, the second derivative of the difference in the variance of the phase almost becomes null. The Masters student Elaasar (2003) has proposed an error control strategy for the Satellite Transport Protocol (STP) that makes it more adaptive to the unique error conditions in satellite access networks. The new strategy is based on an end-to-end probing mechanism that uses the persistence of the error condition as an indication to the kind of prevailing error in the network. The mechanism works by suspending data transmission when an error is detected and investing some time and transmission effort to sense the current delays in the network. The mechanism associates error conditions accompanied by noticeable delays with network congestion.
Otherwise, it associates these errors with different link error events. Using simulation, it is shown that the new probing mechanism for STP indeed improves the effective throughput and increases the energy efficiency of the protocol under various network error conditions. The simulation was carried in PIX (Protocol Implementation Framework for Linux), a tool developed by our group. The Masters student Li (2003) has conducted integration testing of XSTP with a file transport protocol and an ad hoc network protocol. Regarding the ad hoc formation of association groups for secure services and policy distribution mechanisms, use of a presence-based architecture for managing secure services has been proposed by the Ph.D. student Ghavam (2002). This work forms the basis for the development of an enhanced context-based virtual private.

                                                        Maintained by Jeyanthi Hall     Copyrights@CANCCOM 2003    Last modified: Wednesday January 12, 2005