Research & Publications




  • Ongoing Research Project(s):

Underwater Wireless Sensor Networks (UWSNs): A Taxonomy of Routing Protocols
Abstract
    With the rapid advancement in wireless sensor networks (WSNs), researchers are eager to use this technology in the underwater applications. Compared with Terrestrial Wireless Sensor Networks (TWSN), Underwater Wireless Sensor Networks (UWSNs) are characterized with harsh environment, much energy consumption with no option of recharging using solar energy, cost of underwater devices, limited underwater communication range/bandwidth, node movements due to tides and waves and complications in deployment and access to sensor motes. Routing protocols are designed to maintain the routes in the network and they have to guarantee reliable multi-hop communication under these conditions. In this paper, we analyze the design issues of UWSNs and present a categorization and comparison of routing techniques. This comparison discloses the significant features that need to be taken into consideration in designing new routing protocols. We also highlight the advantages and performance issues of each UWSN routing technique and conclude with possible future research areas.

Keywords: Underwater Wireless Sensor Networks, Routing Protocols, Taxonomy




  • Recently Published Research Project:

HDFS+: Erasure Coding Based Hadoop Distributed File System
Published by International Journal of Scientific & Technology Research (IJSTR), ISSN 2277-8616, Volume 2 - Issue 9 September 2013 Edition, pp. 190-197.


Abstract

   A simple replication-based mechanism has been used to achieve high data reliability of Hadoop Distributed File System (HDFS). However, replication based mechanisms have high degree of disk storage requirement since it makes copies of full block without consideration of storage size. Studies have shown that erasure-coding mechanism can provide more storage space when used as an alternative to replication. Also, it can increase write throughput compared to replication mechanism. To improve both space efficiency and I/O performance of the HDFS while preserving the same data reliability level, we propose HDFS+, an erasure coding based Hadoop Distributed File System. The proposed scheme writes a full block on the primary DataNode and then performs erasure coding with Vandermonde-based Reed-Solomon algorithm that divides data into m data fragments and encode them into n data fragments (n>m), which are saved in N distinct DataNodes such that the original object can be reconstructed from any m fragments. The experimental results show that our scheme can save up to 33% of storage space while outperforming the original scheme in write performance by 1.4 times. Our scheme provides the same read performance as the original scheme as long as data can be read from the primary DataNode even under single-node or double-node failure. Otherwise, the read performance of the HDFS+ decreases to some extent. However, as the number of fragments increases, we show that the performance degradation becomes negligible.

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