Pradip De

Graduation Semester and Year

2008

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Computer Science

Department

Computer Science and Engineering

First Advisor

Sajal Das

Abstract

Wireless sensor and actuator networks have been one of the stepping stones towards realizing a pervasive computing infrastructure. However, in a post-deployment scenario, transferring critical updates and reconfigurations on a network-wide scale is a non-trivial proposition. Wireless techniques provide the only means of communication, and consequently, an in-depth study of the multihop broadcast based communication paradigm and the design of efficient and reliable data dissemination protocols for reprogramming a sensor network is of paramount importance. In this dissertation, we initially focus on the formal modeling and performance analysis of broadcast-based data dissemination protocols in wireless sensor networks. The data propagating in the network could be either small configuration information to be shared by all the nodes or a large code image required for reprogramming the network. In order to better understand the propagation behavior, we construct a mathematical model that allows us to compare different dissemination protocols in terms of their speed of propagation and extent of network reachability. Next, from a perspective of security, we investigate the potentially disastrous threat of node compromise originating from a single node infected with a piece of malware, propagating to other nodes and gradually compromising the entire sensor network. Focusing on the possible epidemic breakout of such a propagation, we model and analyze this spreading process and identify key factors determining potential outbreaks. More importantly, we compare the propagation process based on different sensor deployment strategies, for instance, uniform and group-based deployment, thereby getting valuable insights for designing secure networks. Subsequently, we delve onto a specific case of a malware spreading over existing data dissemination protocols in sensor networks. In order to better understand these protocols' vulnerability to piggybacked virus attacks, we construct a mathematical model for the malware infection, incorporating important parameters derived from the communication patterns of the protocol under test. We further enrich our study by observing the effects of a simultaneous recovery process on the infection propagation. The overall result is an approximate but flexible framework to characterize a broadcast protocol in terms of its vulnerability to malware propagation. Having focused on analyzing data dissemination techniques in static sensor networks, we observe that existing data dissemination protocols are inefficient in a mobile environment and require effective modifications to suit the uncertainties and demands of network mobility. Thus, we propose a novel wireless multihop data dissemination protocol, suitable to a mobile sensor network and evaluate it through extensive simulations as well as real testbed implementation on a network of SunSPOT devices. Our results indicate an improved performance of our protocol over existing reprogramming protocols, both in terms of completion time and total number of messages transmitted in the network.

Disciplines

Computer Sciences | Physical Sciences and Mathematics

Comments

Degree granted by The University of Texas at Arlington

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