Synchronous data acquisition with wireless sensor networks

Synchronous data acquisition with wireless sensor networks
Author: Funck, Jürgen Helmut
Publisher: Universitätsverlag der TU Berlin
Total Pages: 352
Release: 2018-07-19
Genre: Computers
ISBN: 379832980X

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.

Wireless Sensor and Actuator Networks

Wireless Sensor and Actuator Networks
Author: Amiya Nayak
Publisher: John Wiley & Sons
Total Pages: 316
Release: 2010-02-12
Genre: Technology & Engineering
ISBN: 9780470570500

This timely book offers a mixture of theory, experiments, and simulations that provides qualitative and quantitative insights in the field of sensor and actuator networking. The chapters are selected in a way that makes the book comprehensive and self-contained. It covers a wide range of recognized problems in sensor networks, striking a balance between theoretical and practical coverage. The book is appropriate for graduate students and practitioners working as engineers, programmers, and technologists.

Dynamic Wireless Sensor Networks

Dynamic Wireless Sensor Networks
Author: Mohamed Elhoseny
Publisher: Springer
Total Pages: 0
Release: 2018-12-13
Genre: Technology & Engineering
ISBN: 9783030065218

This book provides a collection of high-quality research works that address broad challenges in both theoretical and applied aspects of dynamic wireless sensor networks (WSNs) for intelligent and smart applications in a variety of environments. It presents the most central concepts associated with Dynamic Wireless Sensor Networks applications, and discusses issues surrounding Wireless Sensor Network Structures for complex and mobile-based applications. The book subsequently discusses several topics related to energy management in dynamic WSNs, and reviews the steps involved in building a secure and trusted data transmission model using the WSN applications of intelligent environments. Lastly, it discusses the applications of WSNs in live data systems such as SCADA systems. Readers will discover a collection of high-quality research works that address broad challenges in both theoretical and applied aspects of WSNs for intelligent real-life applications. In addition, the book presents original research on the application of a dynamic WSN to solve the problem of energy consumption in a secure WSN during the process of data aggregation and transmission. Written by respected experts in the field, the book will stimulate further efforts in the application of the intelligent WSNs model, helping to solve the problem of data processing in a limited resource WSN-based environment.

Wireless Sensor Networks and Applications

Wireless Sensor Networks and Applications
Author: Yingshu Li
Publisher: Springer Science & Business Media
Total Pages: 444
Release: 2008-02-10
Genre: Computers
ISBN: 0387495924

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.

Data Acquisition Techniques for Next Generation Wireless Sensor Networks

Data Acquisition Techniques for Next Generation Wireless Sensor Networks
Author: Samina Ehsan
Publisher:
Total Pages: 108
Release: 2012
Genre: Animal radio tracking
ISBN:

The meteoric rise and prevalent usage of wireless networking technologies for mobile communication applications have captured the attention of media and imagination of public in the recent decade. One such proliferation is experienced in Wireless Sensor Networks (WSNs), where multimedia enabled elements are fused with integrated sensors to empower tightly coupled interaction with the physical world. As a promising alternative to antiquated wired systems and traditional WSNs in a multitude of novel application scenarios, the newly renovated WSNs have inspired a wide range of research among which investigation on data acquisition techniques is a fundamental one. In this dissertation, we address the problem of data acquisition in next generation WSNs. As wireless sensors are powered with limited energy resources while they are expected to work in an unattended manner for a long duration, energy conservation stands as the primal concern. Also, to enable in-situ sensing in different rate-constrained applications, routing decisions should care about the medium access feasibility of achievable end-to-end data rates. Driven by the fact, we first design cross-layer medium contention aware routing schemes for rate-constrained traffic in single-channel WSNs that maximize network lifetime. Three sufficient conditions on rate feasibility, referred to as rate-based, degree-based, and mixed constraints, are incorporated into the routing formulations to guarantee the practical viability of the routing solutions. Next, with the aim to mitigate interference and hence to enhance network capacity, we extend our work by proposing energy and cross-layer aware routing schemes for multichannel access WSNs that account for radio, MAC contention, and network constraints. In that context, we first derive three new sets of sufficient conditions that ensure feasibility of data rates in multichannel access WSNs. Then, utilizing these sets, we devise three different MAC-aware routing optimization schemes, each aiming to maximize the network lifetime while meeting data rate requirements of end-to-end flows. Finally, we perform extensive simulation studies to evaluate and compare the performance of the proposed routing approaches under various network conditions. So far works are done in milieu of WSNs with both fixed access node and sensor nodes. In the subsequent part of the dissertation, we present the continuation of our work focusing on reliable data acquisition in Mobile WSNs for a promising application namely free-ranging animal tracking/monitoring. To accomplish that goal, we concentrate on providing sufficient conditions on access-point density that limit the likelihood of buffer overflow. We first derive sufficient access-point density conditions that ensure that the data loss rates are statistically guaranteed to remain below a given threshold. Then, we evaluate and validate the derived theoretical results with both synthetic and real-world data.

Security for Wireless Sensor Networks

Security for Wireless Sensor Networks
Author: Donggang Liu
Publisher: Springer Science & Business Media
Total Pages: 214
Release: 2007-02-15
Genre: Technology & Engineering
ISBN: 0387467815

This book discusses fundamental security issues in wireless sensor networks, techniques for the protection of such networks, as well as results from recent studies in wireless sensor network security. It contains example applications for target tracking, scientific exploration and data acquisition in hazardous environments, and includes a fairly new study on capabilities of mu-TESLA, a broadcast authentication technique for wireless sensor networks. The book assists both professionals and students to understand background knowledge in wireless sensor network security and prepare them for producing research in this domain.

Handbook of Sensor Networking

Handbook of Sensor Networking
Author: John R. Vacca
Publisher: CRC Press
Total Pages: 438
Release: 2015-01-13
Genre: Computers
ISBN: 1466569727

This handbook provides a complete professional reference and practitioner's guide to today's advanced sensor networking technologies. It focuses on both established and recent sensor networking theory, technology, and practice. Specialists at the forefront of the field address immediate and long-term challenges and explore practical solutions to a wide range of sensor networking issues. The book covers the hardware of sensor networks, wireless communication protocols, sensor networks software and architectures, wireless information networks, data manipulation, signal processing, localization, and object tracking through sensor networks.