Enhancing network performance and security of limited-resource cyber-physical networks over railway systems and other emerging systems

Abstract

The rapid development of diversified applications of infrastructure networks (e.g., transportation and health-care systems) facilitate the emergence of a new engineering network called cyber-physical networks. These networks face challenges in road to enhancing network performance and security of cyber-physical networks owing to limited resource issues. These limited resource issues include limited amount of available energy to feed the system, low processing capability, limited amount of storage space, and low bandwidth for network communication. Therefore, in this thesis, first, a low-cost lightweight integrated networking solution is proposed for a limited-resource cyber-physical network, which is aimed for realtime detection of missing rail blocks on a railway track. Existing research studies pertinent to railway transportation systems mainly focus on wireless network based solutions for precise localization of trains and non-real-time monitoring of rails for cracks, small breakage, and corrugation. To the best our knowledge, these solutions are not developed through focusing on real-time missing rail block detection as the predominant concern and are not amenable to address the concern. Furthermore, some of these solutions exploit a technique of using high-voltage signal over rail tracks in developed countries. However, in developing countries such as Bangladesh, India, Kenya, etc., where the rail tracks are publicly open, using this sort of technology poses a significant threat to living bodies that are in proximity or even come in contact with the rail lines. Therefore, in this thesis, we introduce a new low-cost lightweight networking paradigm for detecting missing rail blocks.

The proposed networking paradigm is exposed to different security vulnerabilities associated with the inclusion of cyber-physical networks. Existing studies in this regard mainly focus on developing attacks covering replay attack, displacement attack, jamming attack, etc., and their corresponding countermeasures for a Balise-based train control system, which are not directly applicable to the proposed paradigm intended for detecting missing rail blocks. Therefore, in this regard, we introduce a new security threat entitled as power attack exploiting vulnerability pertinent to the low energy source adopted in the proposed paradigm. Consequently, we develop and thoroughly analyzed potential countermeasures for the power attack. Combining all the countermeasures, an integrated networking solution for the purpose of detecting missing rail blocks will be developed. We perform extensive experimentation using both ns-2 simulator and real deployment to investigate the applicability and the effectiveness of our proposed networking solution as well as countermeasures the real-time system for detecting missing rail blocks.

Next part of this research, we focus on network-level performance and security of miniature versions of limited-resource cyber-physical networks, i.e., nanonetworks and body area networks. Existing studies in this regard focus on performance enhancement of nanonetworks via designing new channel models and routing protocols. However, the impacts of different types of nano-antennas having different materials on the network-level performances of the wireless nanonetworks remain still unexplored in the literature. Therefore, in this research, we explore the impacts of using different well-known types of antennas such as dipole, patch, and loop (having different alternative materials available to date, i.e., copper, graphene, and carbon nanotubes) on the network-level performance of wireless nanonetworks from various perspectives such as network throughput, end-to-end delay, delivery ratio, and drop ratio. We perform rigorous simulation using our customized ns-2. Our evaluation demonstrates that a dipole nano-antenna using copper material exhibits around 51% better throughput and about 33% better end-to-end delay compared to other alternatives. Besides, a new security attack entitled power attack, as well as a countermeasure, is also introduced in this research for body area networks, which is a special type of limited- resource cyber-physical networks composed of low-power wearable or implanted wireless medical sensor devices. We analyze the viability of performing power attack in medical body area networks in reality and effectiveness of proposed countermeasure using Mannasim.

Finally, in this thesis, we focus on the other extreme of the limited-resource cyber-physical networks, i.e., smarter version comprising of multi-radio smart devices such as smartphones and tablets. Security aspects of such networks have already been widely explored from different perspectives in the literature. Therefore, in this work, we propose a multi-objective vertical hand-off mechanism to enhance the network-level performance from various perspectives of both network and device-level metrics such as energy consumption, throughput, delay, etc. which yields better scalability and stability. We conduct evaluation comprising both test-bed experiments and ns-2 simulation. The results from both test-bed experiments and ns-2 simulation demonstrate that our proposed mechanism has significant performance improvement over existing state-of-the-art approaches such as GRA and TOPSIS. Furthermore, we endeavor to formulate mathematical models for the different performance metrics of mobile wireless networks. We perform rigorous simulation utilizing ns-2 to capture the performance of mobile wireless networks under diversified settings and develop a lemma as follows: mathematical modeling of mobile wireless networks considering variation in all parameters is not feasible.