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Hemal Shah

  • Assistant Professor
  • Ganpat University
  • 60PublicationsNumber of items in Hemal's My Publications folder on Mendeley.
  • 11Followers


B.Tech in year 1999 and M.Tech in year 2007 from DDIT Nadiad. Currently serving as Assistant Professor at U.V.Patel College of Engineering, Ganpat University, and mehsana having 10 years of teaching experience in field of Computer Engineering & Information Technology. Dissertation had done in ISRO, Ahmadabad under the guidance of Dr. K S Dasgupta on TCP Performance Enhancing Proxies [ PEP] for satellite links. Ph.D research work on Delay tolerant network efficient routing Brief description of my research during M.Tech The newest generation of wireless technology uses TCP [Transmission Control Protocol] at the transport layer, though it is designed and optimized for wired networks. The characteristics of wireless links are significantly different from that of wired network. In wireless links, frequent loss of data is due to the volatile environment. For wired network, loss of data is assumed due to congestion. This assumption of congestion leads to poor performance of TCP in a wireless environment such as wireless LAN [Local Area Network] & WAN [Wide Area Network] and satellite links. Satellite links are characterized by high BER [Bit Error Rate], asymmetric channels and limited link capacity. Performance Enhancing Proxy [PEP] is used to improve the performance of the Internet protocols on network paths where native performance suffers due to characteristics of a link or sub network on the path. Snoop is a well-known method of such a PEP implementation. Snoop caches TCP data segments it receives and forwards and then monitors the end-to-end acknowledgments coming from the receiving TCP end system for DUPACK [Duplicate Acknowledgement] When DUPACK are received, Snoop locally retransmits the lost TCP data segments from its cache, suppressing the DUPACK flowing to the sending TCP end system until acknowledgments for new data are received. Thus, it improves the TCP performance without triggering retransmission and window reduction policies. Research work includes : · Design and development of Snoop as a module for Linux kernel 2.6 with net filter support and performance analysis. The existing Snoop implementation supports Linux kernel 2.4.x only and cannot be used in Linux kernel 2.6 due to massive changes made in the network kernel code. In order to implement the above-mentioned thesis, following work has been partially completed. · Modification of Snoop implementation to fix up the existing bugs such as buffer preparation, synchronization and local timers handling which were found during installation and testing. · Results of Snoop and no Snoop with simulated delay and packet corruption in progress. It is proposed to implement a new Snoop version as a kernel module because: Ø Application program requires writing routines for local timers, memory allocation, connection tracking and synchronization. Ø Lack of standard libraries for linked list and hash data structures. Ø Developing all routines may be complex and time-consuming task. Ø Kernel API supports memory management, local timers, hash functions, synchronization techniques and linked list routines.

Recent publications

  • Inferring friendship network structure by using mobile phone data.

    • Eagle N
    • Pentland A
    • Lazer D
  • Scale-free topology of e-mail networks

    • Ebel H
    • Mielsch L
    • Bornholdt S

Professional experience

Assistant Professor

Ganpat University

August 1999 - Present


Master of Engineering (Gold Medalist)

Dharmsinh Desai University

June 2005 - May 2007(2 years)


Dharmsinh Desai University

March 1995 - May 1999(4 years)

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