Download Free Secure Localization And Time Synchronization For Wireless Sensor And Ad Hoc Networks Book in PDF and EPUB Free Download. You can read online Secure Localization And Time Synchronization For Wireless Sensor And Ad Hoc Networks and write the review.

This book presents the latest research results in the area of secure localization for both wireless mobile ad hoc networks and wireless sensor networks. It is suitable as a text for computer science courses in wireless systems and security. It includes implementation studies with mica2 mote sensors. Due to the open spectrum nature of wireless communication, it is subject to attacks and intrusions. Hence the wireless network synchronization needs to be both robust and secure. Furthermore, issues such as energy constraints and mobility make the localization process even more challenging. The book will also interest developers of secure wireless systems.
This book presents the latest research results in the area of secure localization for both wireless mobile ad hoc networks and wireless sensor networks. It is suitable as a text for computer science courses in wireless systems and security. It includes implementation studies with mica2 mote sensors. Due to the open spectrum nature of wireless communication, it is subject to attacks and intrusions. Hence the wireless network synchronization needs to be both robust and secure. Furthermore, issues such as energy constraints and mobility make the localization process even more challenging. The book will also interest developers of secure wireless systems.
In a computational tour-de-force, this volume wipes away a host of problems related to location discovery in wireless ad-hoc sensor networks. WASNs have recognized potential in many applications that are location-dependent, yet are heavily constrained by factors such as cost and energy consumption. Their “ad-hoc” nature, with direct rather than mediated connections between a network of wireless devices, adds another layer of difficulty. Basing this work entirely on data-driven, coordinated algorithms, the author’s aim is to present location discovery techniques that are highly accurate—and which fit user criteria. The research deploys nonparametric statistical methods and relies on the concept of joint probability to construct error (including location error) models and environmental field models. It also addresses system issues such as the broadcast and scheduling of the beacon. Reporting an impressive accuracy gain of almost 17 percent, and organized in a clear, sequential manner, this book represents a stride forward in wireless localization.
Wireless sensor networks have received a lot of attention recently due to its wide applications. Accurate and synchronized time is crucial in many sensor network applications due to the need for consistent distributed sensing and coordination. A number of time synchronization schemes have been proposed recently to address the resource constraints in sensor networks. However, all these techniques cannot survive malicious attacks in hostile environments. This dissertation includes three secure time synchronization techniques, secure single-hop pair-wise time differences, fault-tolerant cluster-wise time synchronization, and secure and resilient global time synchronization, to achieve time synchronization in different scopes of sensor networks. First, we develop a secure single-hop pair-wise time synchronization technique that provides time difference between two neighbor nodes using hardware-assisted, authenticated medium access control (MAC) layer timestamping. This technique can effectively defeats external attacks that attempt to mislead single-hop pairwise time synchronization. Moreover, it can handle high data rate such as those produced by MICAz motes. Second, we propose a fault-tolerant cluster-wise time synchronization scheme to provide a common clock among a cluster of nodes, where the nodes in the cluster can communicate through broadcast. This scheme guarantees an upper bound of time difference between normal nodes in a cluster, provided that the malicious nodes are no more than one third of the cluster. Unlike the traditional fault-tolerant time synchronization approaches, the proposed technique does not introduce collisions between synchronization messages, nor does it require costly digital signatures. Third, we develop two secure and resilient global time synchronization schemes: level-based time synchronization and diffusion-based time synchronization. The basic idea of both schemes is to provide redundant ways for one node to synchronize its clock wit.
Keywords: wireless sensor network, time synchronization, security.
Wireless sensor networks (WSN) are predicted to play a key role in future technological developments like the internet of things. Already they are beginning to be used in many applications not only in the scientific and industrial domains. One of the biggest challenges, when using WSN, is to fuse and evaluate data from different sensor nodes. Synchronizing the data acquisition of the nodes is a key enabling factor for this. So far research has been focused on synchronizing the clocks of the nodes, largely neglecting the implications for the actual measurement results. This thesis investigates the relation between synchronization accuracy and quality of measurement results. Two different classes of time synchronous data acquisition are investigated: event detection and waveform sampling. A model is developed that describes a WSN as a generic multi-channel data acquisition system, thus enabling direct comparison to other existing systems. With the help of this model it is shown, that synchronization accuracy should best be expressed as uncertainty of the acquired timing information. This way, not only the contribution of the synchronization to the overall measurement uncertainty can be assessed, but also the synchronization accuracy required for an application can be estimated. The insights from the uncertainty analysis are used to develop two distinct approaches to synchronous data acquisition: a proactive and a reactive one. It is shown that the reactive approach can also be used to efficiently implement synchronous angular sampling, i.e. data acquisition synchronous to the rotation of a machine's shaft. Furthermore, testing methods are suggested, that evaluate the synchronized data acquisition of an existing WSN as a whole. These methods can be applied to other data acquisition systems without changes, thus enabling direct comparisons. The practical realization of a WSN is described, on which the developed data acquisition methods have been implemented. All implementations were thoroughly tested in experiments, using the suggested testing methods. This way it was revealed, that a system's interrupt handling procedures may have a strong influence on the data acquisition. Furthermore, it was shown that the effective use of fixed-point arithmetic enables synchronous angular sampling in real-time during a streaming measurement. Finally, two application examples are used to illustrate the utility of the implemented data acquisition: the acoustic localization of two sensor nodes on a straight line and a simple order tracking at an induction motor test bench. Diese Dissertation untersucht die Zusammenhänge zwischen Synchronisationsgenauigkeit und Qualität der Messergebnisse. Zwei Klassen von zeitsynchroner Datenerfassung werden dabei betrachtet: die Detektion von Ereignissen und die Aufnahme von Kurvenformen. Es wird ein Modell entwickelt, welches ein WSN als ein allgemeines mehrkanaliges Datenerfassungssystem beschreibt. Dies ermöglicht den direkten Vergleich zwischen WSN und anderen Messsystemen. Weiter wird mit Hilfe des Modells gezeigt, dass die Synchronisationsgenauigkeit vorzugsweise als Unsicherheit der Zeitinformation angegeben werden sollte. Hierdurch kann nicht nur der Beitrag der Synchronisation zur gesamten Messunsicherheit bestimmt sondern auch die von einer Anwendung tatsächlich benötigte Synchronisationsgenauigkeit abgeschätzt werden. Ausgehend von den durch die Unsicherheitsbetrachtung gewonnenen Erkenntnissen werden ein proaktiver und ein reaktiver Ansatz zur synchronen Datenaufnahme entwickelt. Mit dem reaktiven Ansatz können Messdaten auch effizient drehwinkelsynchron, d. h. synchron zur Drehbewegung einer Maschinenwelle, aufgenommen werden. Es werden Testverfahren vorgeschlagen, mit denen sich die Synchronizität der Datenerfassung für ein WSN als Ganzes überprüfen lässt. Diese Verfahren lassen sich unverändert auf andere Messsysteme anwenden und ermöglichen somit direkte Vergleiche. Es wird die praktische Umsetzung eines WSN beschrieben, auf dem die entwickelten Methoden zur Datenerfassung implementiert wurden. Alle Implementierungen wurden mit den vorgeschlagenen Testverfahren untersucht. Hierdurch konnte gezeigt werden, dass die Interrupt-Bearbeitung der Sensorknoten entscheidenden Einfluss auf die Messdatenerfassung hat. Weiter konnte durch den Einsatz von Fixed-Punkt-Arithmetik die drehwinkelsynchrone Datenerfassung in Echtzeit realisiert werden. Schließlich wird die Nützlichkeit der implementierten Datenerfassung an zwei Anwendungen gezeigt: der akustischen Ortung zweier Sensorknoten sowie einer einfachen Ordnungsanalyse.
A crucial reference tool for the increasing number of scientists who depend upon sensor networks in a widening variety of ways. Coverage includes network design and modeling, network management, data management, security and applications. The topic covered in each chapter receives expository as well as scholarly treatment, covering its history, reviewing state-of-the-art thinking relative to the topic, and discussing currently unsolved problems of special interest.
Wireless sensor networks (WSNs) play an important role in applications such as environmental monitoring, source tracking, and health care,... In WSN, sensors have the ability to perform data sampling, distributed computing and information fusion. To perform such complex tasks, clock synchronization and localization are two fundamental and essential algorithms. WSNs have been widely studied in the past years, and the scientific literature reports many outcomes that make them applicable for some applications. For some others, research still needs to find solutions to some of the challenges posed by battery limitation, dynamicity, and low computing clock rate. With the aim of contributing to the research on WSN, this thesis proposes new algorithms for both clock synchronization and localization. For clock synchronization, sensors converge their local physical clock to perform data fusion. By applying the clock synchronization algorithm, sensors converge the time difference and therefore work at the same rate. In view of dynamicity, low computing and sparsity of WSN, a new pulse-coupled decentralized synchronization algorithm is proposed to improve the precision of the synchronization. The benefit of this kind of algorithm is that sensors only exchange zero-bit pulse instead of packets, so not only the communication is efficient but also robust to any failure of the sensors in the network. Localization of sensors has been widely studied. However, the quality and the accuracy of the localization still have a large room to improve. This thesis apply Leave-out Sign-dominant Correlated Regions (LSCR) algorithm to localization problem. With LSCR, one evaluates the accurate estimates of confidence regions with prescribed confidence levels, which provide not only the location but also the confidence of the estimation. In this thesis, several localization approaches are implemented and compared. The simulation result shows under mild assumptions, LSCR obtains competitive results compared to other methods.