This paper provides a performance evaluation of the TETRAPOL random access protocol. The results are based on a Markovian model which is also presented. The Markovian model is used to derive quality of service parameters, e.g. mean throughput, waiting probability, and mean random access delay. The analytical results are compared to results based on stochastic simulation. Our prototypic implemen...

In this paper, we propose and analyze a multicast application called SOMA (SynchrOnous Multicast Application) which offers multicast file transfer service in an asymmetric intra-campus environment (several interconnected wired and wireless LAN networks interconnected through few routers). For efficient bandwidth utilization, SOMA transmits IP packets by using multicast addressing. We also propo...

Adapting a Delay-based Protocol to Heterogeneous Environments. (August 2008) Kiran Kotla, B.E., Birla Institute of Technology and Science, Pilani, India Co–Chairs of Advisory Committee: Dr A. L. Narasimha Reddy Dr Riccardo Bettati We investigate the issues in making a delay-based protocol adaptive to heterogeneous environments. We assess and address the problems a delay-based protocol faces whe...

considering the major change occurred in business cells from plant to “chain” and the critical need to choose the best partners to form the supply chain for competing in today’s business setting, one of the vital decisions made at the early steps of constructing a business is supplier selection. given the fact that the early decisions are inherently strategic and therefore hard and costly to ch...

The paper focuses on the real-world usage of IEEE 802.11 wireless network encryption and Wi-Fi Protected Setup (WPS) function. A brief history on the development of encryption methods and WPS is given. Wireless scanning of 802.11 networks in a capital city has been performed, and the results of it have been analysed. To ascertain the knowledge about the security of wireless networks of the aver...

Reorganising the index of a search engine based on access frequencies can significantly reduce query evaluation time while maintaining search effectiveness. In this paper we extend access-ordering and introduce a variant index organisation technique that we label accessreordering. We show that by access-reordering an inverted index, query evaluation time can be reduced by as much as 62% over th...

The condition that varieties of cities including Iranian cities are confronted makes the creation of successful public space a necessity. It is clear that for creating suitable public space first we should understand the influencing factors on space and simultaneously solve and improve the problems through understanding the environment. For achieving the factors that influence the success as a ...

OBJECTIVES To compare the physical characteristics of ureteral access sheaths that affect their ability to resist buckling and kinking in the ureter. METHODS Eight commercially available ureteral sheaths were tested. The buckling pressure was measured by adding sequential loads to a point 20 cm from the tip of the sheath until the mass that resulted in buckling of the catheter was determined....

Business requirements for modern enterprise systems usually comprise a variety of dynamic constraints, i. e., constraints that require a complex set of context information only available at runtime. Thus, the efficient evaluation of dynamic constraints, e. g., expressing separation of duties requirements, becomes an important factor for the overall performance of the access control enforcement....