Riasat Aasia’s research while affiliated with University of Bridgeport and other places

A conservative distributed simulation requires all logical processes (LPs) to follow the causality constraint requirement. This implies that all event-messages are processed in strictly timestamp order. Apart from the timestamp of each event generated by LPs, synchronization between all LPs is the second most important requirements. Finally, there must not be a deadlock in the distributed environment. A deadlock may occur when there is no events present in the queue of LP. In such case, to avoid deadlock, Chandy-Misra-Bryant presented an algorithm called Null Message Algorithm (NMA) [3]. These null messages are passed as an event-message to other LPs and it stored in one of queues of LPs. This null message indicates that till the time stamp of that null message, all other events in the queue which have lesser time stamp than null message’s time stamp are safe to process. It means that there won’t be anyarrival of any events from that logical process until current simulation time is equal to the time stamp of the null message. With the time stamp of the null message, a Lookahead value is added to the time stamp of that null message. This Lookahead value can be measure on certain kind of parameters such as delay to transmit a message, propagation delay, etc. therefore, calculating value of Lookahead is the most important part as Lookahead value affects the performance of the conservative distributed event simulation. Proper value of Lookahead can reduce the number of null messages which decreases thetraffic of the network. In this paper, we demonstrate some calculation on the Lookahead which shows the performance of the distributed event simulation

End-System multicasting (ESM) is a promising application-layer scheme that has been recently proposedfor implementing multicast routing in the application layer as a practical alternative to the IPmulticasting. Moreover, ESM is an efficient application layer solution where all the multicastfunctionality is shifted to the end users. However, the limitation in bandwidth and the fact that themessage needs to be forwarded from host-to-host using unicast connection, and consequentlyincrementing the end-to-end delay of the transmission process, contribute to the price to pay for this newapproach. Therefore, supporting high-speed real-time applications such as live streaming multimedia,videoconferencing, distributed simulations, and multiparty games require a sound understanding of thesemulticasting schemes such as IP multicast and ESM and the factors that might affect the end-userrequirements. In this paper, we present both the analytical and the mathematical models for formalizingthe end-to-end delay efficiency of both IP and ESM multicast systems. For the sake of the experimentalverifications of the proposed models, simulation results are presented in this paper. Finally, the proposedformulization can be used to design and implement a more robust and efficient multicast systems for thefuture networks.

This paper presents the implementation of a secure application for an academic institution that offers numerous services to both students and the faculty. The primary focus of this paper is to provide atechnical implementation of a new architecture for encrypting the database. The scope of this paper mainly includes but is not limited to symmetric and public-key cryptography, authentication, keymanagement, and digital signatures. The final results of this paper demonstrate that what security features one should implement in order to achieve a highly secured application. This paper presents theimplementation of a stand alone system that can be implemented on any legacy systems, and still operates effectively. In other words, it is self sufficient in terms of the data that it stores.

End-System multicasting (ESM) is a promising application-layer scheme that has been recently proposed for implementing multicast routing in the application layer as a practical alternative to the IP multicasting. Moreover, ESM is an efficient application layer solution where all the multicast functionality is shifted to the end users. However, the limitation in bandwidth and the fact that the message needs to be forwarded from host-to-host using unicast connection, and consequently incrementing the end-to-end delay of the transmission process, contribute to the price to pay for this new approach. Therefore, supporting high-speed real-time applications such as live streaming multimedia, videoconferencing, distributed simulations, and multiparty games require a sound understanding of these multicasting schemes such as IP multicast and ESM and the factors that might affect the end-user requirements. In this paper, we present both the analytical and the mathematical models for formalizing the end-to-end delay and the bandwidth efficiency of both IP and ESM multicast system. For the sake of the experimental verifications of the proposed models, numerical and simulation results are presented in this paper. Finally, the proposed formulization can be used to design and implement a more robust and efficient multicast systems for the future networks

Extensive studies have been carried out for reducing the handover time of wireless mobile network at medium access control (MAC) layer. However, none of them show the impact of reduced handover timeon the overall performance of wireless mobile networks. This paper presents a quantitative analysis to show the impact of reduced handover time on the performance of wireless mobile networks. The proposed quantitative model incorporates many critical performance parameters involve in reducing the handover time for wireless mobile networks. In addition, we analyze the use of active scanning technique with comparatively shorter beacon interval time in a handoff process. Our experiments verify that the activescanning can reduce the overall handover time at MAC layer if comparatively shorter beacon intervals are utilized for packet transmission. The performance measures adopted in this paper for experimental verifications are network throughput under different network loads.