Дисертації: "Sensor network and distributed systems"

1

Jeong, Dong Hwa. "DISTRIBUTED WIRELESS SENSOR NETWORK SYSTEMS: THEORETICAL FRAMEWORK, ALGORITHMS, AND APPLICATIONS." Case Western Reserve University School of Graduate Studies / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=case1436541959.

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2

Tewatia, Rohit. "Security in Distributed Embedded Systems." Thesis, Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-1379.

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Communication in a sensor network needs guaranteed reception of data without fail and providing security to it. The authenticity and confidentiality of the data has to be ensured as sensors have limited hardware resources as well as the bandwidth. This thesis addresses the security aspects in wireless sensor networks. The main task of the project is to identify the critical security parameters for these distributed embedded systems. The sensors have extremely limited resources: small amount of memory, low computation capability and poor bandwidth. For example, a sensor platform can have 8KB of flash memory, a 4MHz 8-bit Atmel processor, and a 900MHz radio interface. Various security threats posed to these small wireless sensor networks has been made and solutions proposed. Secure communication between these communicating partners is to be achieved using cryptography.

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3

Dehmelt, Chris. "Integration of Smart Sensor Buses into Distributed Data Acquisition Systems." International Foundation for Telemetering, 2005. http://hdl.handle.net/10150/604924.

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ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, Nevada
As requirements for the amount of test data continues to increase, instrumentation engineers are under pressure to deploy data acquisition systems that reduce the amount of associated wiring and overall system complexity. Smart sensor buses have been long considered as one approach to address this issue by placing the appropriate signal conditioners close to their respective sensors and providing data back over a common bus. However, the inability to adequately synchronize the operation of the sensor bus to the system master, which is required to correlate analog data measurements, has precluded their use. The ongoing development and deployment of smart sensor buses has reached the phase in which integration into a larger data acquisition system environment must be considered. Smart sensor buses, such as IntelliBus™, have their own unique mode of operation based on a pre-determined sampling schedule, which however, is typically asynchronous to the operation of the (master or controller) data acquisition system and must be accounted for when attempting to synchronize the two systems. IRIG Chapter 4 type methods for inserting data into a format, as exemplified by the handling of MIL-STD-1553 data, could be employed, with the disadvantage of eliminating any knowledge as to when a particular measurement was sampled, unless it is time stamped (similar to the time stamping function that is provided to mark receipt of 1553 command words). This can result in excessive time data as each sensor bus can manage a large number of analog sensor inputs and multiple sensor buses must be accommodated by the data acquisition system. The paper provides an example, using the Boeing developed IntelliBus system and the L3 Communications - Telemetry East NetDAS system, of how correlated data can be acquired from a smart sensor bus as a major subsystem component of a larger integrated data acquisition system. The focus will be specifically on how the IntelliBus schedule can be synchronized to that of the NetDAS formatter. Sample formats will be provided along with a description of how a standalone NetDAS stack and an integrated NetDAS-IntelliBus system would be programmed to create the required output, taking into account the unique sampling characteristics of the sensor bus.

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4

Luo, Bin, and 羅斌. "Distributed clock synchronization for wireless sensor networks." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/198812.

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Clock synchronization for Wireless Sensor Networks (WSNs) has attracted lots of attention due to its importance for operations in WSNs. In traditional centralized clock synchronization algorithms, all the local information should be transmitted to a fusion center for processing, and the results need to be forwarded back to each individual sensor, thus resulting in a heavy burden on communication and computation in the network. In addition, it also lacks of adaptability to link failures and dynamic changes in the network topology, which greatly prevents their use in WSNs. Hence, in this thesis, we focus on developing energy-efficient distributed clock synchronization algorithms for WSNs. Firstly, global clock synchronization problem is investigated with time-varying clock parameters (skew and offset) owing to imperfect oscillator circuits. A distributed Kalman filter is developed for clock parameters tracking. The proposed algorithm only requires each node to exchange limited information with its direct neighbors, thus is energy efficient, scalable with network size, and is robust against changes in network connectivity. A low-complexity distributed algorithm based on Coordinate-Descent with Bootstrap (CD-BS) is also proposed to provide rapid initialization of the tracking algorithm. Simulation results show that the proposed distributed tracking algorithm achieves the long-term accuracy for the clock parameters close to the Bayesian Cramer-Rao Lower Bound. Secondly, the problem of global clock synchronization for WSNs in the presence of unknown exponential delays is studied. The joint maximum likelihood estimator of clock offsets, clock skews and fixed delays of the network is first formulated as a global linear programming (LP) problem. Based on the Alternating Direction Method of Multipliers (ADMM), we propose a fully-distributed synchronization algorithm that has low communication overhead and computation cost. Simulation results show that the proposed algorithm achieves better accuracy than consensus algorithm and the distributed least squares algorithm, and can always converge to the centralized optimal solution. Finally, global clock synchronization for WSNs under the exponentially distributed delays is re-visited with the fast convergence min-sum algorithm. The synchronization problem is cast into an optimization problem represented by factor graph, and a closed-form expression of the messages passed between nodes are derived. Simulation results show that this distributed algorithm can approach the centralized LP solution with faster convergence speed compared to ADMM-based algorithm.
published_or_final_version
Electrical and Electronic Engineering
Doctoral
Doctor of Philosophy

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5

Cheung, Victor. "Distributed position estimation for wireless sensor networks /." View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?COMP%202006%20CHEUNG.

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6

Ocean, Michael James. "The Sensor Network Workbench: Towards Functional Specification, Verification and Deployment of Constrained Distributed Systems." Boston University Computer Science Department, 2009. https://hdl.handle.net/2144/1713.

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As the commoditization of sensing, actuation and communication hardware increases, so does the potential for dynamically tasked sense and respond networked systems (i.e., Sensor Networks or SNs) to replace existing disjoint and inflexible special-purpose deployments (closed-circuit security video, anti-theft sensors, etc.). While various solutions have emerged to many individual SN-centric challenges (e.g., power management, communication protocols, role assignment), perhaps the largest remaining obstacle to widespread SN deployment is that those who wish to deploy, utilize, and maintain a programmable Sensor Network lack the programming and systems expertise to do so. The contributions of this thesis centers on the design, development and deployment of the SN Workbench (snBench). snBench embodies an accessible, modular programming platform coupled with a flexible and extensible run-time system that, together, support the entire life-cycle of distributed sensory services. As it is impossible to find a one-size-fits-all programming interface, this work advocates the use of tiered layers of abstraction that enable a variety of high-level, domain specific languages to be compiled to a common (thin-waist) tasking language; this common tasking language is statically verified and can be subsequently re-translated, if needed, for execution on a wide variety of hardware platforms. snBench provides: (1) a common sensory tasking language (Instruction Set Architecture) powerful enough to express complex SN services, yet simple enough to be executed by highly constrained resources with soft, real-time constraints, (2) a prototype high-level language (and corresponding compiler) to illustrate the utility of the common tasking language and the tiered programming approach in this domain, (3) an execution environment and a run-time support infrastructure that abstract a collection of heterogeneous resources into a single virtual Sensor Network, tasked via this common tasking language, and (4) novel formal methods (i.e., static analysis techniques) that verify safety properties and infer implicit resource constraints to facilitate resource allocation for new services. This thesis presents these components in detail, as well as two specific case-studies: the use of snBench to integrate physical and wireless network security, and the use of snBench as the foundation for semester-long student projects in a graduate-level Software Engineering course.

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7

Pandit, Saurav. "Approximation algorithms for distributed systems." Diss., University of Iowa, 2010. https://ir.uiowa.edu/etd/870.

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Distributed Approximation is a new and rapidly developing discipline that lies at the crossroads of various well-established areas of Computer Science - Distributed Computing, Approximation Algorithms, Graph Theory and often, Computational Geometry. This thesis focuses on the design and analysis of distributed algorithms to solve optimization problems that usually arise in large-scale, heavily dynamic, resource constrained networks, e.g. wireless ad-hoc and sensor networks, P2P systems, mobile networks etc. These problems can often be abstracted by variations of well-known combinatorial optimization problems, such as topology control, clustering etc. Many of these problems are known to be hard (NP-complete). But we need fast and light-weight distributed algorithms for these problems, that yield near-optimal solutions. The results presented in this thesis can be broadly divided in two parts. The first part contains a set of results that obtain improved solutions to the classic problem of computing a sparse "backbone" for Wireless Sensor Networks (WSNs). In graph-theoretic terms, the goal is to compute a spanning subgraph of the input graph, that is sparse, lightweight and has low stretch. The term "low stretch" indicates that in spite of dropping many edges, the distance between any two nodes in the graph is not increased by much. We model WSNs as geometric graphs - unit ball graphs, quasi-unit ball graphs etc. in Euclidean spaces, as well as in more general metric spaces of low doubling dimension. We identify and exploit a variety of geometric features of those models to obtain our results. In the second part of the thesis we focus on distributed algorithms for clustering problems. We present several distributed approximation algorithms for clustering problems (e.g., minimum dominating set, facility location problems) that improve on best known results so far. The main contribution here is the design of distributed algorithms where the running time is a "tunable" parameter. The advent of distributed systems of unprecedented scale and complexity motivates the question of whether it is possible to design algorithms that can provide non-trivial approximation guarantees even after very few rounds of computation and message exchanges. We call these algorithms "k-round algorithms". We design k-round algorithms for various clustering problems that yield non-trivial approximation factors even if k is a constant. Additionally, if k assumes poly-logarithmic values, our algorithms match or improve on the best-known approximation factors for these problems.

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8

Hiremath, Naveen. "SenMinCom pervasive distributed dynamic sensor data mining for effective commerce /." unrestricted, 2008. http://etd.gsu.edu/theses/available/etd-07172008-230611/.

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Thesis (M.S.)--Georgia State University, 2008.
Title from file title page. Yanqing Zhang, committee chair; Rajshekhar Sunderraman, Ying Zhu, committee members. Electronic text (64 p. : ill. (some col.)) : digital, PDF file. Description based on contents viewed Nov. 19, 2008. Includes bibliographical references (p. 59-64).

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9

Techateerawat, Piya, and piyat33@yahoo com. "Key distribution and distributed intrusion detection system in wireless sensor network." RMIT University. Electrical and Computer Systems Engineering, 2008. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080729.162610.

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This thesis proposes a security solution in key management and Intrusion Detection System (IDS) for wireless sensor networks. It addresses challenges of designing in energy and security requirement. Since wireless communication consumes the most energy in sensor network, transmissions must be used efficiently. We propose Hint Key Distribution (HKD) for key management and Adaptive IDS for distributing activated IDS nodes and cooperative operation of these two protocols. HKD protocol focuses on the challenges of energy, computation and security. It uses a hint message and key chain to consume less energy while self-generating key can secure the secret key. It is a proposed solution to key distribution in sensor networks. Adaptive IDS uses threshold and voting algorithm to distribute IDS through the network. An elected node is activated IDS to monitor its network and neighbors. A threshold is used as a solution to reduce number of repeated activations of the same node. We attempt to distribute the energy use equally across the network. In a cooperative protocol, HKD and Adaptive IDS exchange information in order to adjust to the current situation. The level of alert controls the nature of the interaction between the two protocols.

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10

Breza, Michael. "Bio-inspired tools for a distributed wireless sensor network operating system." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/14404.

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The problem which I address in this thesis is to find a way to organise and manage a network of wireless sensor nodes using a minimal amount of communication. To find a solution I explore the use of Bio-inspired protocols to enable WSN management while maintaining a low communication overhead. Wireless Sensor Networks (WSNs) are loosely coupled distributed systems comprised of low-resource, battery powered sensor nodes. The largest problem with WSN management is that communication is the largest consumer of a sensor node’s energy. WSN management systems need to use as little communication as possible to prolong their operational lifetimes. This is the Wireless Sensor Network Management Problem. This problem is compounded because current WSN management systems glue together unrelated protocols to provide system services causing inter-protocol interference. Bio-inspired protocols provide a good solution because they enable the nodes to self-organise, use local area communication, and can combine their communication in an intelligent way with minimal increase in communication. I present a combined protocol and MAC scheduler to enable multiple service protocols to function in a WSN at the same time without causing inter-protocol interference. The scheduler is throughput optimal as long as the communication requirements of all of the protocols remain within the communication capacity of the network. I show that the scheduler improves a dissemination protocol’s performance by 35%. A bio-inspired synchronisation service is presented which enables wireless sensor nodes to self organise and provide a time service. Evaluation of the protocol shows an 80% saving in communication over similar bio-inspired synchronisation approaches. I then add an information dissemination protocol, without significantly increasing communication. This is achieved through the ability of our bio-inspired algorithms to combine their communication in an intelligent way so that they are able to offer multiple services without requiring a great deal of inter-node communication.

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11

Krishna, Ashwin. "Composing and connecting devices in animal telemetry network." Kansas State University, 2016. http://hdl.handle.net/2097/32882.

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Master of Science
Department of Computing and Information Sciences
Venkatesh P. Ranganath
As the Internet of Things (IoT) continues to grow, the need for services that span multiple application domains will continue to increase to realise the numerous possibilities enabled by IoT. Today, however, heterogeneity among devices leads to interoperability issues while building a system of systems and often give rise to closed ecosystems. The issues with interoperability are driven by the inability of devices and apps from different vendors to communicate with each other. The interoperability problem forces the users to stick to one particular vendor, leading to vendor lock-in. To achieve interoperability, the users have to do the heavy lifting (at times impossible) of connecting heterogeneous devices. As we slowly move towards system-of-systems and IoT, there is a real need to support heterogeneity and interoperability. A recent effort in Santos Lab developed Medical Device Coordination Framework (MDCF), which was a step to address these issues in the space of human medical systems. Subsequently, we have been wondering if a similar solution can be employed in the area of animal science. In this effort, by borrowing observations from MDCF and knowledge from on-field experience, we have created a demonstration showcasing how a combination of precise component descriptions (via DSL) and communication patterns can be used in software development and deployment to overcome barriers due to heterogeneity, interoperability and to enable an open ecosystem of apps and devices in the space of animal telemetry.

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12

Bahceci, Israfil. "Multiple-Input Multiple-Output Wireless Systems: Coding, Distributed Detection and Antenna Selection." Diss., Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-08262005-022321/.

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Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2006.
Altunbasak, Yucel, Committee Chair ; Mersereau, Russell M., Committee Member ; Fekri, Faramarz, Committee Member ; Smith, Glenn, Committee Member ; Huo, Xiaoming, Committee Member. Includes bibliographical references.

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13

Chachra, Sumit, and Theodore Elhourani. "RESOURCE ALLOCATION IN SENSOR NETWORKS USING DISTRIBUTED CONSTRAINT OPTIMIZATION." International Foundation for Telemetering, 2004. http://hdl.handle.net/10150/605299.

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International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, California
Several algorithms have been proposed for solving constraint satisfaction and the more general constraint optimization problem in a distributed manner. In this paper we apply two such algorithms to the task of dynamic resource allocation in the sensor network domain using appropriate abstractions. The aim is to effectively track multiple targets by making the sensors coordinate with each other in a distributed manner, given a probabilistic representation of tasks (targets). We present simulation results and compare the performance of the DBA and DSA algorithms under varying experimental settings.

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14

Davis, Jesse, Ron Kyker, and Nina Berry. "DESCRIPTION AND ANALYSIS OF A FLEXIBLE HARDWARE ARCHITECTURE FOR EVENT-DRIVEN DISTRIBUTED SENSOR NETWORK NODES." International Foundation for Telemetering, 2003. http://hdl.handle.net/10150/605356.

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International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada
A particular engineering aspect of distributed sensor networks that has not received adequate attention is the system level hardware architecture of the individual nodes of the network. A novel hardware architecture based on an idea of task specific modular computing is proposed to provide for both the high flexibility and low power consumption required for distributed sensing solutions. The power consumption of the architecture is mathematically analyzed against a traditional approach, and guidelines are developed for application scenarios that would benefit from using this new design.

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15

Mei, Jian. "Distributed Coverage Control of Multi-Agent System in Convective–Diffusive Time Evolving Environments." Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/39601.

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Using multi-agent systems to execute a variety of missions such as environmental monitoring and target tracking has been made possible by the advances in control techniques and computational capabilities. Communication abilities between agents allow them to coact and execute several coordinated missions, among which there is optimal coverage. The optimal coverage problem has several applications in engineering theory and practice, as for example in environmental monitoring, which belongs to the broad class of resource allocation problems, in which a ﬁnite number of mobile agents have to be deployed in a given spatial region with the assignment of a sub-region to each agents with respect to a suitable coverage metric. The coverage metric encodes the sensing performance of individual agent with respect to points inside the domain of interest, and a distribution of risk density. Usually the risk density function measures the relative importance assigned to inner regions. The optimal coverage problem in which the risk density is time-invariant has been widely studied in previous research. The solution to this class of problems is centroidal Voronoi tessellation, in which each agent is located on the centroid of the related Voronoi cell. However, there are many scenarios that require to be modelled by time-varying risk density rather than time-invariant one, as for example in area coverage problems where the environment evolves independently of the evolution for the robotic agents deployed to cover the area. In this work, the changing environment is modeled by a time-varying density function which is governed by a convection-diffusion equation. Mixed boundary conditions are considered to model a scenario in which a diffusive substance (e.g., oil from a leaking event or radioactive material from a nuclear accident) enters the area with convective component from the boundary. A non-autonomous feed- back law is employed whose generated trajectories maximize the coverage metric. The asymptotic stability of the multi-agent system is proven by using Barbalat’s lemma, and then theoretical predictions are illustrated by several simulations that represent idealized scenarios.

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16

Sanli, Ozgur. "Rule-based In-network Processing For Event-driven Applications In Wireless Sensor Networks." Phd thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613389/index.pdf.

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Wireless sensor networks are application-specific networks that necessitate the development of specific network and information processing architectures that can meet the requirements of the applications involved. The most important challenge related to wireless sensor networks is the limited energy and computational resources of the battery powered sensor nodes. Although the central processing of information produces the most accurate results, it is not an energy-efficient method because it requires a continuous flow of raw sensor readings over the network. As communication operations are the most expensive in terms of energy usage, the distributed processing of information is indispensable for viable deployments of applications in wireless sensor networks. This method not only helps in reducing the total amount of packets transmitted and the total energy consumed by sensor nodes, but also produces scalable and fault-tolerant networks. Another important challenge associated with wireless sensor networks is that the possibility of sensory data being imperfect and imprecise is high. The requirement of precision necessitates employing expensive mechanisms such as redundancy or use of sophisticated equipments. Therefore, approximate computing may need to be used instead of precise computing to conserve energy. This thesis presents two schemes that distribute information processing for event-driven reactive applications, which are interested in higher-level information not in the raw sensory data of individual nodes, to appropriate nodes in sensor networks. Furthermore, based on these schemes, a fuzzy rule-based system is proposed that handles imprecision, inherently present in sensory data.

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17

Lu, Yapeng. "An integrated algorithm for distributed optimization in networked systems." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B43224234.

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18

Richard, Mark G. "Cooperative control of distributed autonomous systems with applications to wireless sensor networks." Thesis, Monterey, Calif. : Naval Postgraduate School, 2009. http://edocs.nps.edu/npspubs/scholarly/theses/2009/Jun/09Jun%5FRichard.pdf.

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Thesis (M.S. in Mechanical Engineering)--Naval Postgraduate School, June 2009.
Thesis Advisor(s): Lee, Deok Jin ; Kaminer, Issac I. "June 2009." Description based on title screen as viewed on 13 July 2009. Author(s) subject terms: Unmanned Aerial Vehicle, UAV, extremum seeking, simulink, high bandwidth communication links, SNR Model, coordinated control, cooperative control, decentralized control, wireless sensor network. Includes bibliographical references (p. 51). Also available in print.

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19

Ghosh, Dastidar Kajari. "Programming and self stabilization for wireless sensor networks." Diss., University of Iowa, 2009. https://ir.uiowa.edu/etd/363.

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Ubiquitous computing has become a widespread phenomenon in today's modern world, with the computing technology integrating with our daily life in an invisible manner. Embedded systems and wireless sensor networks are popular choices to achieve this. Programming embedded and sensor network systems has always been a challenge for the programmers due to the lack of sufficient high-level programming support. To deal with this serious limitation, we have developed DESAL (Dynamic Embedded Sensing and Actuation Language) which is a user-friendly high-level programming language for wireless sensor networks with an integrated middleware, which hides the low-level detail from the programmers. In this thesis we present the design and development of DESAL. We have made DESAL programs rule based. Programs are written in guard-action format defined in terms of the program states. There are established formal correctness proving methods that can work on guard-action formats to mathematically check a program for errors. Also, there is no hidden control context like events or interrupts. Time synchronization has been developed as part of the middleware that lets DESAL programs to coordinate through synchronized actions throughout the network. This facilitates classic coordination algorithms like clock synchronization, spanning tree construction and consensus. Also, synchronized wake up saves energy. Neighborhood management, including node discovery and monitoring, is also provided by the middleware. DESAL programs communicate via state sharing. There is no network programming required. The middleware provides that automatically. Combining all these features DESAL provides major network management services, and yet presents the users with a simple high-level programming interface. We implemented the DESAL compiler to convert DESAL programs to NesC on TinyOS and to Java. Another novel feature we have introduced in DESAL is a variable of type 'token'. The concept of token is commonly used in mutual exclusion algorithms. One of the case studies we have done uses the token variable to achieve increased lifetime of sensors in a ring topology. The working of token is hidden from the user. The token mechanism developed achieves self-stabilization in the system. Another case study with tokens involves selective activation of RFID tags in a scenario where among the three RFID tags present only one can work at a time. Struct is a new data structure introduced in DESAL. Sometimes we need to group together two or more variables. It is important to receive them at the same time. Hence, it is important to send these grouped data over the radio together. Struct does that. Function is another newly added feature to DESAL. Function is added to group together repeated statements in a program. The unique feature of function is that, it uses only global variables. No new local variable is declared. This can significantly reduce the stack overhead of the program, thus saving memory and running time. Case studies have been done to illustrate the features of DESAL and to find scope for improvement.

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20

Jiang, Bing. "Ubiquitous monitoring of distributed infrastructures /." Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/6118.

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21

Lu, Yapeng, and 呂亞鵬. "An integrated algorithm for distributed optimization in networked systems." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B43224234.

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22

Motjolopane, Bokang Patrick. "A power harvesting technique to facilitate energy conversion in distributed wireless sensor networks." Thesis, Cape Peninsula University of Technology, 2008. http://hdl.handle.net/20.500.11838/1113.

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Анотація:

Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2008. Includes bibliographical references (leaves 67-72).
Distributed wireless sensor networks (DWSNs) are applied in a variety of applications that can enhance the quality of human life or even save lives, such as in fire monitoring, where DWSN microsensors relay the exact location of the fire to water sprinkler actors to automatically extinguish the fire. Batteries are currently the predominant source of energy in DWSNs. one of the key obstacles in the adoption of DWSN technology is the limited lifetime of batteries in microsensors. Recharging or replacing depleted batteries can significantly increase costs in DWSNs. The aim of this study is to address the power challenge in DWSNs by proposing a sixteen-element equiangular spiral rectenna to ahrvest ambient microwave energy to supply indoor DWSNs. The study concludes that this rectenna model has the potential to generate power that enables long periods of operation of the DWSNs without human intervention in the power manageement process, thus reducing maintenance and administration costs. The efficiency of the rectenna model was tested in an anechoic chamber. Efficiency test results indicated that the highest efficiency of 2% for the rectenna model was achieved as 2 GHz for an ambient power of -6 dBm across a 1 K ohm load resistence. The study further concludes that the current rectenna model size of sixteen elements is a limiting factor for the deployment of DWSNs.

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23

Yu, Chen. "SCHEDULING AND RESOURCE MANAGEMENT FOR COMPLEX SYSTEMS: FROM LARGE-SCALE DISTRIBUTED SYSTEMS TO VERY LARGE SENSOR NETWORKS." Doctoral diss., Orlando, Fla. : University of Central Florida, 2009. http://purl.fcla.edu/fcla/etd/CFE0002907.

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24

Khan, Kashif. "A distributed computing architecture to enable advances in field operations and management of distributed infrastructure." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/a-distributed-computing-architecture-to-enable-advances-in-field-operations-and-management-of-distributed-infrastructure(a9181e99-adf3-47cb-93e1-89d267219e50).html.

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Distributed infrastructures (e.g., water networks and electric Grids) are difficult to manage due to their scale, lack of accessibility, complexity, ageing and uncertainties in knowledge of their structure. In addition they are subject to loads that can be highly variable and unpredictable and to accidental events such as component failure, leakage and malicious tampering. To support in-field operations and central management of these infrastructures, the availability of consistent and up-to-date knowledge about the current state of the network and how it would respond to planned interventions is argued to be highly desirable. However, at present, large-scale infrastructures are “data rich but knowledge poor”. Data, algorithms and tools for network analysis are improving but there is a need to integrate them to support more directly engineering operations. Current ICT solutions are mainly based on specialized, monolithic and heavyweight software packages that restrict the dissemination of dynamic information and its appropriate and timely presentation particularly to field engineers who operate in a resource constrained and less reliable environments. This thesis proposes a solution to these problems by recognizing that current monolithic ICT solutions for infrastructure management seek to meet the requirements of different human roles and operating environments (defined in this work as field and central sides). It proposes an architectural approach to providing dynamic, predictive, user-centric, device and platform independent access to consistent and up-to-date knowledge. This architecture integrates the components required to implement the functionalities of data gathering, data storage, simulation modelling, and information visualization and analysis. These components are tightly coupled in current implementations of software for analysing the behaviour of networks. The architectural approach, by contrast, requires they be kept as separate as possible and interact only when required using common and standard protocols. The thesis particularly concentrates on engineering practices in clean water distribution networks but the methods are applicable to other structural networks, for example, the electricity Grid. A prototype implementation is provided that establishes a dynamic hydraulic simulation model and enables the model to be queried via remote access in a device and platform independent manner.This thesis provides an extensive evaluation comparing the architecture driven approach with current approaches, to substantiate the above claims. This evaluation is conducted by the use of benchmarks that are currently published and accepted in the water engineering community. To facilitate this evaluation, a working prototype of the whole architecture has been developed and is made available under an open source licence.

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25

Magnússon, Sindri. "Distributed Optimization with Nonconvexities and Limited Communication." Licentiate thesis, KTH, Reglerteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-181111.

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In economical and sustainable operation of cyber-physical systems, a number of entities need to often cooperate over a communication network to solve optimization problems. A challenging aspect in the design of robust distributed solution algorithms to these optimization problems is that as technology advances and the networks grow larger, the communication bandwidth used to coordinate the solution is limited. Moreover, even though most research has focused distributed convex optimization, in cyberphysical systems nonconvex problems are often encountered, e.g., localization in wireless sensor networks and optimal power flow in smart grids, the solution of which poses major technical difficulties. Motivated by these challenges this thesis investigates distributed optimization with emphasis on limited communication for both convex and nonconvex structured problems. In particular, the thesis consists of four articles as summarized below. The first two papers investigate the convergence of distributed gradient solution methods for the resource allocation optimization problem, where gradient information is communicated at every iteration, using limited communication. In particular, the first paper investigates how distributed dual descent methods can perform demand-response in power networks by using one-way communication. To achieve the one-way communication, the power supplier first broadcasts a coordination signal to the users and then updates the coordination signal by using physical measurements related to the aggregated power usage. Since the users do not communicate back to the supplier, but instead they only take a measurable action, it is essential that the algorithm remains primal feasible at every iteration to avoid blackouts. The paper demonstrates how such blackouts can be avoided by appropriately choosing the algorithm parameters. Moreover, the convergence rate of the algorithm is investigated. The second paper builds on the work of the first paper and considers more general resource allocation problem with multiple resources. In particular, a general class of quantized gradient methods are studied where the gradient direction is approximated by a finite quantization set. Necessary and sufficient conditions on the quantization set are provided to guarantee the ability of these methods to solve a large class of dual problems. A lower bound on the cardinality of the quantization set is provided, along with specific examples of minimal quantizations. Furthermore, convergence rate results are established that connect the fineness of the quantization and number of iterations needed to reach a predefined solution accuracy. The results provide a bound on the number of bits needed to achieve the desired accuracy of the optimal solution. The third paper investigates a particular nonconvex resource allocation problem, the Optimal Power Flow (OPF) problem, which is of central importance in the operation of power networks. An efficient novel method to address the general nonconvex OPF problem is investigated, which is based on the Alternating Direction Method of Multipliers (ADMM) combined with sequential convex approximations. The global OPF problem is decomposed into smaller problems associated to each bus of the network, the solutions of which are coordinated via a light communication protocol. Therefore, the proposed method is highly scalable. The convergence properties of the proposed algorithm are mathematically and numerically substantiated. The fourth paper builds on the third paper and investigates the convergence of distributed algorithms as in the third paper but for more general nonconvex optimization problems. In particular, two distributed solution methods, including ADMM, that combine the fast convergence properties of augmented Lagrangian-based methods with the separability properties of alternating optimization are investigated. The convergence properties of these methods are investigated and sufficient conditions under which the algorithms asymptotically reache the first order necessary conditions for optimality are established. Finally, the results are numerically illustrated on a nonconvex localization problem in wireless sensor networks. The results of this thesis advocate the promising convergence behaviour of some distributed optimization algorithms on nonconvex problems. Moreover, the results demonstrate the potential of solving convex distributed resource allocation problems using very limited communication bandwidth. Future work will consider how even more general convex and nonconvex problems can be solved using limited communication bandwidth and also study lower bounds on the bandwidth needed to solve general resource allocation optimization problems.

QC 20160203

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26

Stenbrunn, Alf, and Theodor Lindquist. "Hosting a building management system on a smart network camera: On the development of an IoT system." Thesis, Malmö högskola, Fakulteten för teknik och samhälle (TS), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-20517.

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The Internet of Things (IoT) is an umbrella term for smart things connected to the Internet. Connected sensors may be used to the benefit of smart building management systems. This thesis describes the development of a sensor based building management system prototype, lightweight enough to run on a single network camera. The focus of the research was investigating if the system prototype was scalable, and capable of storing and analyzing data gathered from a large amount of sensors relevant to the field of building management. The prototype was developed through a five-stage systems development process, and evaluated using simulations and case studies. The finished prototype was able to gather and store data from a few hundred real-time sensors using limited hardware. Tests showed that the network camera should be capable of managing at least 100 sensors. The system itself is scalable with the use of more powerful hardware. However, using a distributed architecture would be preferable if more sensors are required. This could be achieved by creating a distributed network of cameras, where each camera manages its own set of sensors. This could both increase scalability and make the system more robust and reliable.

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27

Deconda, Keerthi. "Fault tolerant pulse synchronization." Thesis, [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-2331.

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28

Magnússon, Sindri. "Bandwidth Limited Distributed Optimization with Applications to Networked Cyberphysical Systems." Doctoral thesis, KTH, Nätverk och systemteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-205682.

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Анотація:

The emerging technology of Cyberphysical systems consists of networked computing, sensing, and actuator devices used to monitor, connect, and control physical phenomena. In order to economically and sustainably operate Cyberphysical systems, their devices need to cooperate over a communication network to solve optimization problems. For example, in smart power grids, smart meters cooperatively optimize the grid performance, and in wireless sensor networks a number of sensors cooperate to find optimal estimators of real-world parameters. A challenging aspect in the design of distributed solution algorithms to these optimization problems is that while the technology advances and the networks grow larger, the communication bandwidth available to coordinate the solution remains limited. Motivated by this challenge, this thesis investigates the convergence of distributed solution methods for resource allocation optimization problems, where gradient information is communicated at every iteration, using limited communication. This problem is approached from three different perspectives, each presented in a separate paper. The investigation of the three papers demonstrate promises and limits of solving distributed resource allocation problems using limited communication bandwidth. Future work will consider how even more general problems can be solved using limited communication bandwidth and also study different communication constraints.

QC 20170424

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29

Shi, Hong-Ling. "Development of an energy efficient, robust and modular multicore wireless sensor network." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2014. http://tel.archives-ouvertes.fr/tel-00968069.

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The wireless sensor network is a key technology in the 21st century because it has multitude applications and it becomes the new way of interaction between physical environment and computer system. Moreover, the wireless sensor network is a high resource constraint system. Consequently, the techniques used for the development of traditional embedded systems cannot be directly applied. Today wireless sensor nodes were implemented by using only one single processor architecture. This approach does not achieve a robust and efficient energy wireless sensor network for applications such as precision agriculture (outdoor) and telemedicine. The aim of this thesis is to develop a new approach for the realization of a wireless sensor network node using multicore architecture to enable to increase both its robustness and lifetime (reduce energy consumption).

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30

Bergelt, René, Matthias Vodel, and Wolfram Hardt. "Generische Datenerfassung und Aufbereitung im Kontext verteilter, heterogener Sensor-Aktor-Systeme." Universitätsbibliothek Chemnitz, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-94681.

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Die vorgestellte Arbeit präsentiert ein geschlossenes Konzept für die synchronisierte Erfassung, Verarbeitung und Aufbereitung beliebiger Sensor-Informationen. Es ist nun möglich, heterogene Sensornetze sowie dedizierte, autarke Messsysteme zeitlich zu koordinieren und entsprechend in Relation zu setzen. Auf Basis von XML erfolgt die ganzheitliche Beschreibung des Monitoring-Szenarios und die Einordnung der einzelnen Datensätze. Die Informationen können nun in beliebigen Ausgabeformaten anwendungsspezifisch definiert und visualisiert werden. Zusätzlich ermöglichen Mechanismen zur gezielten Messwert-Vorverarbeitung und -Filterung eine Senkung des benötigten Datenvolumens. Die Funktionalität des vorgestellten GREASE-Frameworks wird am Beispiel eines geschlossenen Test-Systems aus dem Automotive-Bereich evaluiert. Dabei wird die vorhandene Sensorik eines Kfz-Bordnetzes mit einem zusätzlichen Netzwerk aus Sensorknoten verfeinert. Die korrelierten Daten werden anschließend für die Visualisierung mittels Google Earth, jBEAM und anderen Lösungen aufbereitet.

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31

Niklasson, Johan, and Oskar Hahr. "Topology optimization for distributed consensus in multi-agent networks." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-259352.

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Distributed networks, meaning a network in which several agents work together unanimously to perform some task in order to reach goals has become a field with a wide range of applications. One such applications may exist in the form of drones with a purpose of observing and detecting forest fires. In such applications it can be of paramount importance to be able to agree over some opinions or values between the agents. This value could be something such as event detection or a general direction to fly in. However in such a network there might not exist a central hub and it would not be possible for all drones to communicate directly with each other. In order for such a network to be able to reach consensus or agreement, values have to be exchanged between the agents. This thesis focuses on a subset of this problem known as distributed averaging. In the thesis it is investigated how a networks ability to detect forest fires and communicate both efficiently and quickly can change when the number of agents are adjusted in the network. The results showed that, when operating in a fixed area, for a small network of drones the increasing effective energy cost per drone were higher, than that of a larger network. It was also discovered that the speed at which a network could reach an agreement was not necessarily affected by the size of the network. But as the field area being observed was increased, adverse effects were observed in terms of communication and event detection.
Distribuerade nätverk bestående av flera agenter som har som uppgift att tillsammans nå gemensamma resultat har blivit allt mer populärt. Ett sådant användningsområde är hur drönare kan användas för att observera och upptäcka skogsbränder över en given yta. I en sådan tillämpning är det av stor vikt att drönarnätverket kan kommunicera och kongruera över värden nätverket delar med varandra. Dessa värden kan representera händelser som nätverket har som uppgift att upptäcka eller en riktning för drönarna att flyga i. Det är inte alltid garanterat att det finns en central kommunikationscentral för sådana nätverk, utan blir beroende på att kommunicera med varandra för att utbyta och kongruera över värden. Den här rapporten fokuserar på en avgränsad del av det ovanstående problemet som kallas för distribuerat konsensusvärde (eng. distributed averaging). Rapporten undersöker hur ett sådant nätverks konvergeringsförmåga, totala energikostnad samt täckning påverkas när fler drönare tillförs till nätverket. När arbetsytan var satt till statisk storlek visade resultaten att den tillförda energikostnaden per drönare var högre för små nätverk än för större nätverk. Det visades också att hastigheten som nätverket når ett kongruerande värde inte nödvändigtvis påverkas av storleken av nätverket. När arbetsytan ökade i takt med storleken på nätverket observerades däremot motsatt effekt för energikostnad och hastigheten för att nå ett konsensusvärde.

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32

Gnanapandithan, Nithya. "Data detection and fusion in decentralized sensor networks." Thesis, Manhattan, Kan. : Kansas State University, 2005. http://hdl.handle.net/2097/132.

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33

Kraus, K. (Klemens). "Security management process in distributed, large scale high performance systems." Doctoral thesis, Oulun yliopisto, 2014. http://urn.fi/urn:isbn:9789526206783.

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Abstract In recent years the number of attacks on critical infrastructure has not only increased substantially but such attacks have also shown higher sophistication. With the increasing interconnection of information systems it is common that critical systems communicate and share information outside an organization’s networks for many different scenarios. In the academic world as well as in existing security implementations, focus is placed on individual aspects of the security process - for example, network security, legal and regulatory compliance and privacy - without considering the process on the whole. This work focuses on solving this security gap of critical infrastructure by providing solutions for emerging attack vectors. Using design science research methods, a model was developed that seeks to combine these individual security aspects to form a complete security management process (SMP). This SMP introduces, among others theories of security topics, recommended best practices and a security organization structure. An instantiation of the SMP model was implemented for a large-scale critical infrastructure. This work introduces the system developed, its architecture, personnel hierarchy and security relevant workflows. Due to employed surveillance networks, specialized requirements for bandwidth utilization while preserving data security were present. Thus algorithms for solving these requirements are introduced as sub-constructs. Other focus points are the managerial aspects of sensors deployed in surveillance networks and the automatic processing of the sensor data to perform data fusion. Algorithms for both tasks were developed for the specific system but could be generalized for other instantiations. Verification was performed by empirical studies of the instantiation in two separate steps. First the instantiation of the SMP was analyzed as a whole. One of the main quality factors of the instantiation is incident response time, especially in complex scenarios. Consequently measurements of response times when handling incidents compared to the traditional system were performed in different scenarios. System usability was then verified by user acceptance tests of operators and administrators. Both studies indicate significant improvements compared to traditional security systems. Secondly, the sub-constructs communication optimizations and the data fusion algorithm were verified showing substantial improvements in their corresponding areas
Tiivistelmä Viime vuosina kriittisiin infrastruktuureihin on kohdistunut merkittävästi aiempaa enemmän erilaisia hyökkäyksiä. Tietojärjestelmien välisten yhteyksien lisääntymisen myötä myös kriittiset järjestelmät kommunikoivat nykyään keskenään ja jakavat tietoa organisaation sisäisten verkkojen ulkopuolellekin. Akateemisessa tutkimuksessa ja turvajärjestelmien toteutuksissa on huomio kohdistettu turvallisuutta koskevien prosessien yksittäisiin piirteisiin, kuten esimerkiksi verkkojen turvallisuuteen, lakien ja sääntöjen noudattamiseen ja yksityisyyteen, miettimättä prosesseja kokonaisuutena. Väitöstutkimuksen tavoitteena on ollut ratkaista tämä kriittisten infrastruktuurien turvallisuusongelma tarjoamalla ratkaisuja, jotka paljastavat mahdollisia hyökkäysreittejä. Väitöstutkimuksessa kehitettiin suunnittelutieteellisen tutkimuksen avulla lähestymistapa, joka yhdistää yksittäiset turvallisuusnäkökohdat ja muodostaa näin turvallisuuden kokonaishallinnan prosessin mallin. Malli hyödyntää erilaisia turvallisuusteorioita, suositeltuja hyviä käytäntöjä ja turvallisen organisaation rakennemalleja. Mallista kehitettiin esimerkkitoteutus laajamittaista kriittistä infrastruktuuria varten. Tämä väitöskirja esittelee kehitetyn järjestelmän, sen arkkitehtuurin, henkilökuntahierarkian ja turvallisuuden kannalta relevantit työnkulkukaaviot. Työssä huomioitiin laajan valvontaverkoston edellyttämät erityisvaatimukset tilanteessa, jossa tietoturvallisuuden säilyttäminen oli tärkeää. Myös näiden erityisvaatimuksiin liittyvien mallin osien ratkaisualgoritmit esitetään. Muita työn tuotoksia ovat hallinnolliset näkökulmat, jotka on huomioitava, kun valvonnalle tärkeitä sensoreita hallinnoidaan ja sensorien tuottamaa dataa yhdistellään. Algoritmit luotiin esimerkkiympäristöön, mutta niitä on mahdollista soveltaa muihinkin toteutuksiin. Toteutuksen oikeellisuuden todentamisessa käytettiin empiirisiä ympäristöjä kahdessa eri vaiheessa. Ensiksi turvallisuusprosessin kokonaishallinnan malli analysoitiin kokonaisuutena. Merkittävä laatutekijä oli havaintotapahtuman vasteaika erityisesti monimutkaisissa skenaarioissa. Siksi työssä esitellään eri skenaarioiden avulla tapahtumanhallinnan vasteaikojen mittauksia suhteessa perinteisiin järjestelmiin. Tämän jälkeen järjestelmän käytettävyys todennettiin operaattorien ja hallintohenkilöstön kanssa tehtyjen hyväksymistestien avulla. Testit osoittivat huomattavaa parannusta verrattuna perinteisiin turvajärjestelmiin. Toiseksi verifiointiin mallin osien kommunikaation optimointi ja algoritmien toimivuus erikseen ja niissäkin ilmeni huomattavia parannuksia perinteisiin järjestelmiin verrattuna

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34

Borkar, Milind. "A distributed Monte Carlo method for initializing state vector distributions in heterogeneous smart sensor networks." Diss., Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22680.

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The objective of this research is to demonstrate how an underlying system's state vector distribution can be determined in a distributed heterogeneous sensor network with reduced subspace observability at the individual nodes. We show how the network, as a whole, is capable of observing the target state vector even if the individual nodes are not capable of observing it locally. The initialization algorithm presented in this work can generate the initial state vector distribution for networks with a variety of sensor types as long as the measurements at the individual nodes are known functions of the target state vector. Initialization is accomplished through a novel distributed implementation of the particle filter that involves serial particle proposal and weighting strategies, which can be accomplished without sharing raw data between individual nodes in the network. The algorithm is capable of handling missed detections and clutter as well as compensating for delays introduced by processing, communication and finite signal propagation velocities. If multiple events of interest occur, their individual states can be initialized simultaneously without requiring explicit data association across nodes. The resulting distributions can be used to initialize a variety of distributed joint tracking algorithms. In such applications, the initialization algorithm can initialize additional target tracks as targets come and go during the operation of the system with multiple targets under track.

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35

Alshahrany, Falah. "Hybrid intelligent decision support system for distributed detection based on ad hoc integrated WSN & RFID." Thesis, Brunel University, 2016. http://bura.brunel.ac.uk/handle/2438/13380.

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The real time monitoring of environment context aware activities, based on distributed detection, is becoming a standard in public safety and service delivery in a wide range of domains (child and elderly care and supervision, logistics, circulation, and other). The safety of people, goods and premises depends on the prompt immediate reaction to potential hazards identified in real time, at an early stage to engage appropriate control actions. Effective emergency response can be supported only by available and acquired expertise or elaborate collaborative knowledge in the domain of distributed detection that include indoor sensing, tracking and localizing. This research proposes a hybrid conceptual multi-agent framework for the acquisition of collaborative knowledge in dynamic complex context aware environments for distributed detection. This framework has been applied for the design and development of a hybrid intelligent multi-agent decision system (HIDSS) that supports a decentralized active sensing, tracking and localizing strategy, and the deployment and configuration of smart detection devices associated to active sensor nodes wirelessly connected in a network topology to configure, deploy and control ad hoc wireless sensor networks (WSNs). This system, which is based on the interactive use of data, models and knowledge base, has been implemented to support fire detection and control access fusion functions aimed at elaborating: An integrated data model, grouping the building information data and WSN-RFID database, composed of the network configuration and captured data, A virtual layout configuration of the controlled premises, based on using a building information model, A knowledge-based support for the design of generic detection devices, A multi-criteria decision making model for generic detection devices distribution, ad hoc WSNs configuration, clustering and deployment, and Predictive data models for evacuation planning, and fire and evacuation simulation. An evaluation of the system prototype has been carried out to enrich information and knowledge fusion requirements and show the scope of the concepts used in data and process modelling. It has shown the practicability of hybrid solutions grouping generic homogeneous smart detection devices enhanced by heterogeneous support devices in their deployment, forming ad hoc networks that integrate WSNs and radio frequency identification (RFID) technology. The novelty in this work is the web-based support system architecture proposed in this framework that is based on the use of intelligent agent modelling and multi-agent systems, and the decoupling of the processes supporting the multi-sensor data fusion from those supporting different context applications. Although this decoupling is essential to appropriately distribute the different fusion functions, the integration of several dimensions of policy settings for the modelling of knowledge processes, and intelligent and pro-active decision making activities, requires the organisation of interactive fusion functions deployed upstream to a safety and emergency response.

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36

Sitanayah, Lanny. "Finding boundary cycles in location-free low density wireless sensor networks for mobile target tracking." University of Western Australia. School of Computer Science and Software Engineering, 2009. http://theses.library.uwa.edu.au/adt-WU2009.0158.

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Wireless Sensor Networks (WSNs) comprise a large number of sensor nodes, which are spread out within a region and communicate using wireless links. In some WSN applications, recognizing boundary nodes is important for topology discovery, geographic routing and tracking. In this thesis, we study the problem of identifying the boundary nodes of a WSN. In a WSN, close-by nodes can communicate with their neighbors and have the ability to estimate distances to nearby nodes, but not necessarily the true distances. Our objective is to find the boundary nodes by using the connectivity relation and neighbor distance information without any knowledge of node locations. Moreover, our main aim is to design a distributed algorithm that works even when the average degree is low. We propose a heuristic algorithm to find the boundary nodes which are connected in a boundary cycle of a location-free, low density, randomly deployed WSN. We develop the key ideas of our boundary detection algorithm in the centralized scenario and extend these ideas to the distributed scenario. Then, we show by simulation experiments that the distributed implementation outperforms the centralized one. The centralized implementation relies on the connectivity of the network to the base station. Therefore, for low density disconnected networks, the algorithm cannot find boundaries in partitions of the network that cannot establish connection to the base station. This condition leads to a low quality of boundary discovery. In contrast, the distributed implementation is more realistic for real WSNs, especially for relatively sparse networks when all local information cannot be collected very well due to sparse connectivity. In low-degree disconnected networks, the simulation results show that the distributed implementation has a higher quality of boundaries compared to the centralized implementation.

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37

Tricaud, Christophe. "Optimal Sensing and Actuation Policies for Networked Mobile Agents in a Class of Cyber-Physical Systems." DigitalCommons@USU, 2010. https://digitalcommons.usu.edu/etd/673.

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The main purpose of this dissertation is to define and solve problems on optimal sensing and actuating policies in Cyber-Physical Systems (CPSs). Cyber-physical system is a term that was introduced recently to define the increasing complexity of the interactions between computational hardwares and their physical environments. The problem of designing the ``cyber'' part may not be trivial but can be solved from scratch. However, the ``physical'' part, usually a natural physical process, is inherently given and has to be identified in order to propose an appropriate ``cyber'' part to be adopted. Therefore, one of the first steps in designing a CPS is to identify its ``physical'' part. The ``physical'' part can belong to a large array of system classes. Among the possible candidates, we focus our interest on Distributed Parameter Systems (DPSs) whose dynamics can be modeled by Partial Differential Equations (PDE). DPSs are by nature very challenging to observe as their states are distributed throughout the spatial domain of interest. Therefore, systematic approaches have to be developed to obtain the optimal locations of sensors to optimally estimate the parameters of a given DPS. In this dissertation, we first review the recent methods from the literature as the foundations of our contributions. Then, we define new research problems within the above optimal parameter estimation framework. Two different yet important problems considered are the optimal mobile sensor trajectory planning and the accuracy effects and allocation of heterogeneous sensors. Under the remote sensing setting, we are able to determine the optimal trajectories of remote sensors. The problem of optimal robust estimation is then introduced and solved using an interlaced ``online'' or ``real-time'' scheme. Actuation policies are introduced into the framework to improve the estimation by providing the best stimulation of the DPS for optimal parameter identification, where trajectories of both sensors and actuators are optimized simultaneously. We also introduce a new methodology to solving fractional-order optimal control problems, with which we demonstrate that we can solve optimal sensing policy problems when sensors move in complex media, displaying fractional dynamics. We consider and solve the problem of optimal scale reconciliation using satellite imagery, ground measurements, and Unmanned Aerial Vehicles (UAV)-based personal remote sensing. Finally, to provide the reader with all the necessary background, the appendices contain important concepts and theorems from the literature as well as the Matlab codes used to numerically solve some of the described problems.

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38

Kohlmeyer, Eckhard Bernhard. "A cross-layer approach for optimizing the efficiency of wireless sensor and actor networks." Diss., Pretoria : [s.n.], 2009. http://upetd.up.ac.za/thesis/available/etd-06252009-124552/.

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39

Davis, Cledo L. "The systems integration of autonomous behavior analysis to create a "Maritime Smart Environment" for the enhancement of maritime domain awareness." Thesis, Monterey, California : Naval Postgraduate School, 2010. http://edocs.nps.edu/npspubs/scholarly/theses/2010/Jun/10Jun%5FDavis.pdf.

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Анотація:

Thesis (M.S. in Systems Engineering)--Naval Postgraduate School, June 2010.
Thesis Advisor(s): Goshorn, Rachel ; Goshorn, Deborah. "June 2010." Description based on title screen as viewed on June 24, 2010. Author(s) subject terms: Anomaly Detection, Artificial Intelligence, Automation, Behavior Analysis, Distributed Artificial Intelligence, Intelligence-Surveillance-Reconnaissance, Maritime Domain Awareness, Maritime Force Protection, Multi-agent Systems, Network-centric Operations, Network-centric Systems Engineering, Network-centric Warfare, Smart Sensor Networks, Systems Engineering, Systems Integration, System of Systems. Includes bibliographical references (p. 209-212). Also available in print.

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40

Nae, Yakov. "Modelo distribuído para agregação de armazenamento em redes de sensores sem fio=Distributed model for storage aggregation in wireless sensor networks." [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/260109.

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Анотація:

Orientador: Lee Luan Ling
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
Made available in DSpace on 2018-08-20T02:24:35Z (GMT). No. of bitstreams: 1 YakovNae_M.pdf: 7990917 bytes, checksum: 122c511d9ba839a2f1464fbe7fca09b4 (MD5) Previous issue date: 2011
Resumo: Gerência de armazenamento em Redes de Sensores Sem Fio (RSSF) é uma questão muito crítica. Além da RSSFs conter uma vasta quantidade de armazenamento agregada, ela não pode ser usada inteiramente. Portanto, o sistema inteiro falha quando o primeiro sensor tem sua capacidade de armazenamento esgotada, deixando uma grande capacidade de armazenamento inutilizada. Sugere-se que os sensores devem-se ser capazes de detectar as capacidades de armazenamentos inutilizadas, para prolongar as suas funcionalidades. Entretanto, em RSSF de larga escala isso pode ser muito difícil uma vez que os sensores podem não ter conhecimento da existência dos outros. Neste trabalho apresenta-se duas principais contribuições: otimização da capacidade total de armazenamento para RSSF em grande escala e uma nova abordagem de roteamento - Deterministic "Random" Walk (Passeio "Aleatório" Determinístico). Apresenta-se um novo modelo de armazenamento via construção "sob demanda" de Cadeias de Armazenamento Distribuídas ( Distributed Storage Chains (DSC). Estas cadeias representam parcerias entrem os sensores que podem compartilhar suas capacidades de armazenamento. Resultando, os sensores não estão sujeitos às suas limitações de armazenamento, mas para à capacidade total de armazenamento disponível no sistema. Constrói-se estas cadeia via passeio determinístico sobre a topologia sugerida. Todavia, mostra-se que estes passeios apresentam um comportamento aleatório que é muito eficiente em termos de localização de capacidade de armazenamento disponível
Abstract: Storage management of Wireless Sensor Networks (WSN) is a very critical issue in terms of system's lifetime. While WSNs host a vast storage capacity on the aggregate, that capacity cannot be used entirely. Eventually, the entire network may fail when the first sensor has its own storage capacity depleted, leaving behind a large amount of unutilized storage capacity. We suggest that sensors should be able to detect unutilized storage capacity in order to prolong their functionality. However, for large scale WSNs this can be a difficult task, since sensors may not be aware of the existence of others. This work has two main contributions: an optimization of the overall storage capacity for large scale WSNs and a novel routing approach of deterministic "random" walk. We present a new storage model by building "on - demand" Distributed Storage Chains (DSC). These chains represent partnership between sensors that share their storage capacity. As a result, sensors are no longer subjected to their own storage limitations but to the total amount of available storage in the WSN. We construct these chains via deterministic walks over our suggested topology. However, we show that these walks resemble the behavior of random walks and are therefore highly efficient in terms of locating available storage
Mestrado
Telecomunicações e Telemática
Mestre em Engenharia Elétrica

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41

Perez, Alfredo Jose. "An Architecture for Global Ubiquitous Sensing." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3276.

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A new class of wireless sensor networks has recently appeared due to the pervasiness of cellular phones with embedded sensors, mobile Internet connectivity, and location technologies. This mobile wireless sensor network has the potential to address large-scale societal problems and improve the people's quality of life in a better, faster and less expensive fashion than current solutions based on static wireless sensor networks. Ubiquitous Sensing is the umbrella term used in this dissertation that encompasses location-based services, human-centric, and participatory sensing applications. At the same time, ubiquitous sensing applications are bringing a new series of challenging problems. This dissertation proposes and evaluates G-Sense, for Global-Sense, an architecture that integrates mobile and static wireless sensor networks, and addresses several new problems related to location-based services, participatory sensing, and human-centric sensing applications. G-Sense features the critical point algorithms, which are specific mechanisms to reduce the power consumption by continous sensing applications in cellular phones, and reduce the amount of data generated by these applications. As ubiquitous sensing applications have the potential to gather data from many users around the globe, G-Sense introduces a peer-to-peer system to interconnect sensing servers based on the locality of the data. Finally, this dissertation proposes and evaluates a multiobjective model and a hybrid evolutionary algorithm to address the efficient deployment of static wireless sensor nodes when monitoring critical areas of interest.

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Faye, Sébastien. "Contrôle et gestion du trafic routier urbain par un réseau de capteurs sans fil." Thesis, Paris, ENST, 2014. http://www.theses.fr/2014ENST0061/document.

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Les transports terrestres occupent une place majeure dans notre société, notamment en ville où les ralentissements aux heures de pointe peuvent avoir un impact notable sur l'organisation des activités, l'économie ou encore l'écologie. Les infrastructures routières sont généralement coordonnées par un centre de contrôle, responsable du maintien des équipements, de leurs réglages initiaux et de la gestion des incidents (matériels ou humains). Les nouvelles technologies de l'information et de la communication ont permis, en l'espace de quelques années, de mettre en œuvre des systèmes de transport intelligents. À l'aide de multiples points de mesures répartis sur le territoire, un opérateur peut dénombrer les usagers et en déduire la charge du réseau. Toutefois, centraliser les informations présente de nombreuses limites. Cette thèse vise à étudier l'emploi de systèmes distribués afin de mettre en œuvre des systèmes de transport intelligents grâce à un réseau de capteurs sans fil. Couplés à une unité de détection (p. ex., un magnétomètre), les capteurs communicants peuvent réagir au passage d'un véhicule en étant déployés, par exemple, sur les voies. Ils sont également capables de coopérer et de s'affranchir d'une entité centrale, rendant tout ou partie d'une zone urbaine totalement indépendante. D'autre part, ces réseaux peuvent fonctionner de manière autonome et tolèrent mieux les pannes, car aucun élément n'est indispensable au fonctionnement global du système. Enfin, les éléments de ces réseaux sont petits, peu coûteux, et communiquent en sans fil, ce qui leur permet d'être déployés et redéployés rapidement et de manière dense
Road traffic has a significant effect on metropolitan activities, especially during peak hours when it impacts on areas such as the economy and the environment. Road infrastructure is typically coordinated from a control centre that is responsible for maintaining not only its equipment but also their initial settings and incident management (both material and human). During the past few years, new technologies in the fields of information and communication have led to the introduction of intelligent transportation systems. Using multiple measurement points distributed across a country, an operator can count road users and calculate the network load. However, the centralization of information has a number of drawbacks. The aim of this thesis is to study the use of distributed systems in order to implement intelligent transportation systems via a wireless sensor network. Coupled to a detection unit (e.g., a magnetometer), the interconnected sensors can respond to the passage of a vehicle when deployed, for example, along the road. They can also work together without recourse to a central entity - rendering all or part of an urban area totally independent. Furthermore, these networks can operate autonomously and are less susceptible to breadown, because the overall running of the system is not affected by the failure of individual components. Finally, components are small and cheap, and they operate wirelessly, which means they can be deployed and redeployed both rapidly and densely

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43

MORBEE, MARLEEN. "Optimized information processing in resource-constrained vision systems. From low-complexity coding to smart sensor networks." Doctoral thesis, Universitat Politècnica de València, 2011. http://hdl.handle.net/10251/12126.

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Vision systems have become ubiquitous. They are used for traffic monitoring, elderly care, video conferencing, virtual reality, surveillance, smart rooms, home automation, sport games analysis, industrial safety, medical care etc. In most vision systems, the data coming from the visual sensor(s) is processed before transmission in order to save communication bandwidth or achieve higher frame rates. The type of data processing needs to be chosen carefully depending on the targeted application, and taking into account the available memory, computational power, energy resources and bandwidth constraints. In this dissertation, we investigate how a vision system should be built under practical constraints. First, this system should be intelligent, such that the right data is extracted from the video source. Second, when processing video data this intelligent vision system should know its own practical limitations, and should try to achieve the best possible output result that lies within its capabilities. We study and improve a wide range of vision systems for a variety of applications, which go together with different types of constraints. First, we present a modulo-PCM-based coding algorithm for applications that demand very low complexity coding and need to preserve some of the advantageous properties of PCM coding (direct processing, random access, rate scalability). Our modulo-PCM coding scheme combines three well-known, simple, source coding strategies: PCM, binning, and interpolative coding. The encoder first analyzes the signal statistics in a very simple way. Then, based on these signal statistics, the encoder simply discards a number of bits of each image sample. The modulo-PCM decoder recovers the removed bits of each sample by using its received bits and side information which is generated by interpolating previous decoded signals. Our algorithm is especially appropriate for image coding.
Morbee, M. (2011). Optimized information processing in resource-constrained vision systems. From low-complexity coding to smart sensor networks [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/12126
Palancia

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Müller, Ivan. "Gerenciamento descentralizado de redes sem fio industriais segundo o padrão WirelessHART." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2012. http://hdl.handle.net/10183/76169.

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O uso de equipamentos sem fio em sistemas de monitoramento e controle de processos industriais vem aumentando gradativamente. Os elevados custos de cabeamento incentivam os gerentes de fábricas para que considerem o uso de sistemas industriais sem fio, uma vez que estes promovem grandes reduções nos custos de instalação finais. Entretanto, a robustez do enlace de rádio frequência e os requerimentos de comunicação em tempo real são frequentemente citados como obstáculos reais para o uso de tecnologias sem fio na indústria. À frente das demais organizações, a HART Foundation lançou em 2007 o WirelessHART, sendo este o primeiro padrão aberto de comunicação sem fio especificamente desenvolvido para ambientes industriais. Apesar de ser um protocolo seguro e de propiciar comunicação em tempo real, o estudo aprofundado do WirelessHART revela diversas possibilidades de melhorias. Nesse protocolo, o gerenciamento da rede é feito de forma centralizada, o que garante maior simplicidade e controle sobre o escalonamento, roteamento e a segurança das mensagens. Por outro lado, grandes latências, especialmente nos processos de conexão e desconexão de nós, impossibilitam o uso de dispositivos móveis ou intermitentes. A concentração do gerenciamento em um só elemento também leva à fragilidade do sistema: na falha do gerenciador central, toda rede fica inoperante. Neste trabalho, é apresentada uma arquitetura de rede WirelessHART inovadora, que utiliza coprocessadores gerenciadores distribuídos para possibilitar a descentralização do gerenciamento e consequentemente as suas vantagens. O sistema desenvolvido permite diferentes configurações descentralizadas, parciais ou totais, e com mínimas modificações no protocolo original. A arquitetura de rede proposta mantém os dispositivos de campo com suas características originais, de baixo custo e consumo, além de permitir a coexistência com equipamentos certificados. A metodologia para a descentralização é apresentada e o estudo de caso realizado permite a avaliação da proposta. A originalidade deste trabalho é verificada através do estudo do estado da arte. Os resultados obtidos de um estudo de caso demonstram o grande potencial da proposta, com reduções significativas nos tempos de agregação e manutenção da rede. A proposta de descentralização possibilita configurações e modos operacionais antes impossíveis no WirelessHART, tais como o uso de dispositivos móveis ou intermitentes e o emprego de técnicas de handover.
The use of wireless devices in industrial systems for process monitoring and control has been gradually increasing. The high costs of cabling encourage plant managers to consider the use of such industrial wireless systems, since they promote large reductions in final costs. However, the link robustness and the real-time communication requirements are frequently cited as real obstacles to the use of wireless technologies in the industry. Ahead of other organizations, the HART Foundation launched the in 2007WirelessHART, which is the first open standard for wireless communications developed specifically for industrial environments. WirelessHART is a reliable and secure protocol and provide real-time communications but the thorough study of this protocol reveals several possibile improvements. In this protocol, network management is done centrally, ensuring simplicity and control over the scheduling, routing and messaging security. Moreover, large latency, especially in the connection and disconnection processes of field devices, preclude the use of mobile or intermittent devices. The concentration of one element in management also leads to the system fragility: if the central manager fails the entire network fail. In this work, a innovative WirelessHART network achitecture is presented and implemented by means of hardware-based distributed network manager coprocessors to enable decentralization and its blessings. The developed system allows different decentralized, partial or total architectures with minimal changes to the original protocol. A hardware-based solution maintains field devices with its low cost and consumption features and allow coexistence with certified equipment. The decentralization methodology along with its originality is presented and case study allows the evaluation of the proposal. The results demonstrate the architecture has great potential with significant reductions in join and maintenance times. The proposed decentralization enables configurations and operating modes previously impossible in WirelessHART such as the use of mobile or intermittent devices and handover techniques.

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45

Casbeer, David W. "Decentralized Estimation Using Information Consensus Filters with a Multi-static UAV Radar Tracking System." Diss., CLICK HERE for online access, 2009. http://contentdm.lib.byu.edu/ETD/image/etd2779.pdf.

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46

Nguyen, Le-Duy-Lai. "Contrôle distribué multi-couche des systèmes complexes avec contraintes de communication : application aux systèmes d'irrigation." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAT108/document.

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Cette thèse présente une contribution sur les problèmes de contrôle de réseaux d'irrigations en tenant compte des contraintes de communication grâce à une approche multicouches d’intelligence distribuée. Les analyses détaillées de chaque couche avec les résultats analytiques et les simulations seront décrites dans les différents chapitres. Ils mettent l'accent sur l'intérêt de l'approche multicouches, plus précisément sur son efficacité et sa fiabilité pour la supervision, l'optimisation multi-objectifs et le contrôle coopératif distribué sur des systèmes complexes de transport d'eau.La première couche analysé est le réseau hydraulique composé de canaux d’écoulements à surface libre, de sous-réseaux maillés de tuyaux sous pression et des structures hydrauliques (pompes vannes, ..). En intégrant les équations de Saint-Venant pour décrire l’écoulement physique des fluides en surface libre et la méthode Lattice Boltzmann pour la simulation du fluide, nous obtenons un modèle non linéaire discret pour les canaux à surface libre. Les structures hydrauliques sont généralement traitées comme des limites internes des biefs (tronçons) et modélisées par des relations entre les variables de flux et de pression.Permettant l'échange d'informations entre les éléments du système de contrôle, le réseau de communication sera considéré comme la deuxième couche. La résolution des problèmes d’hétérogénéités des systèmes et des communications (par exemple les retards de diffusion dans le réseau, la perte de paquets, la consommation d'énergie) sera étudié en introduisant une architecture de réseau hybride avec un routage dynamique basé sur les exigences de Qualité de Service (QoS) des applications de contrôle. Pour le routage dynamique dans le réseau, une composition pondérée de certaines métriques standards est proposée afin que le protocole de routage utilisant cette métrique composite converge sans boucle avec une « route » optimum. Grâce à différents scénarios de simulation, plusieurs critères de performance du réseau ont été évalués. La comparaison des résultats de simulation permet de valider l'intérêt de cette approche de composition pour le routage dynamique.Une troisième couche propose un système de contrôle réactif optimal développé pour la régulation du réseau d'irrigation dans un modèle étendue à grande échelle : Distributed Cooperative Model Predictive Control (DCMPC). Cette partie aborde la mise en œuvre de différentes stratégies de contrôle (centralisées, décentralisées et distribuées) et intègre la communication coopérative entre les contrôleurs MPC locaux afin d’améliorer les performances global es du système. La gestion de la divergence dans l'échange d'informations entre les contrôleurs est considérée comme un problème de consensus et résolue en utilisant un protocole de consensus asynchrone. Cette approche du contrôle distribué basée sur le paradigme des systèmes multi-agents, fournit une solution garantissant que tous les contrôleurs aient une vue cohérente de certaines valeurs des données nécessaires pour le calcul de décision. Un cas d’application sur un canal d'irrigation est étudié dans les simulations. La comparaison des résultats de simulations valide les avantages de l'approche du contrôle distribué coopératif par rapport aux autres stratégies de contrôle
This thesis presents control problems of irrigation network with communication constraints and a multi-layer approach to solve these problems in a distributed manner. Detailed discussions of each layer with analytical and simulation results are described throughout several chapters. They emphasize the potential interest of the multi-layer approach, more precisely its efficiency and reliability for supervision, multi-objective optimization and distributed cooperative control of complex water transport systems. Conventionally, the first layer to be considered is the hydraulic network composed of free-surface channels, hydraulic structures and mesh subnetwork of pressurized pipes. By coupling the Saint-Venant equations for describing the physics of free-surface ﬂuid and the Lattice Boltzmann method for the ﬂuid simulation, a discrete-time nonlinear model is obtained for channel reaches. The hydraulic structures are usually treated as internal boundaries of reaches and modeled by algebraic relationships between the ﬂow and pressure variables. To enable the exchange of information among the control system’s components, a communication network is considered in the second layer. Solving challenging problems of heterogeneous devices and communication issues (e.g., network delay, packet loss, energy consumption) is investigated in this thesis by introducing a hybrid network architecture and a dynamic routing design based on Quality of Service (QoS) requirements of control applications. For network routing, a weighted composition of some standard metrics is proposed so that the routing protocol using the composite metric achieves convergence, loop-freeness and path-optimality properties. Through extensive simulation scenarios, different network performance criteria are evaluated. The comparison of simulation results can validate the interest of this composition approach for dynamic routing. Finally, the third layer introduces an optimal reactive control system developed for the regulatory control of large-scale irrigation network under a Distributed Cooperative Model Predictive Control (DCMPC) framework. This part discusses the implementation of different control strategies (e.g., centralized, decentralized, and distributed strategies) and how the cooperative communication among local MPC controllers can be included to improve the performance of the overall system. Managing divergent (or outdated) information exchange among controllers is considered in this thesis as a consensus problem and solved by an asynchronous consensus protocol. This approach based on the multi-agent system paradigm to distributed control requires each controller to agree with its neighbors on some data values needed during action computation. For simulations, a particular benchmark of an irrigation channel is considered. The comparison of simulation results validate the benefits of the distributed cooperative control approach over other control strategies

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47

Rashid, Md Jayedur. "Extending a networked robot system to include humans, tiny devices, and everyday objects." Doctoral thesis, Örebro universitet, Akademin för naturvetenskap och teknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-15247.

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In networked robot systems (NRS), robots and robotic devices are distributed in the environment; typically tasks are performed by cooperation and coordination of such multiple networked components. NRS offer advantages over monolithic systems in terms of modularity, flexibility and cost effectiveness, and they are thus becoming a mainstream approach to the inclusion of robotic solutions in everyday environments. The components of a NRS are usually robots and sensors equipped with rich computational and communication facilities. In this thesis, we argue that the capabilities of a NRS would greatly increase if it could also accommodate among its nodes simpler entities, like small ubiquitous sensing and actuation devices, home appliances, or augmented everyday objects. For instance, a domestic robot needs to manipulate food items and interact with appliances. Such a robot would benefit from the ability to exchange information with those items and appliances in a direct way, in the same way as with other networked robots and sensors. Combining such highly heterogeneous devices inside one NRS is challenging, and one of the major challenges is to provide a common communication and collaboration infrastructure. In the field of NRS, this infrastructure is commonly provided by a shared middleware. Unfortunately, current middlewares lack the generality needed to allow heterogeneous entities such as robots, simple ubiquitous devices and everyday objects to coexist in the same system. In this thesis we show how an existing middleware for NRS can be extended to include three new types of “citizens” in the system, on peer with the other robots. First, we include computationally simple embedded devices, like ubiquitous sensors and actuators, by creating a fully compatible tiny version of the existing robotic middleware. Second, we include augmented everyday objects or home appliances which are unable to run the middleware on board, by proposing a generic design pattern based on the notion of object proxy. Finally,we go one step further and include humans as nodes in the NRS by defining the notion of human proxy. While there exist a few other NRS which are able to include both robots and simple embedded devices in the same system, the use of proxies to include everyday objects and humans in a generic way is a unique feature of this work. In order to verify and validate the above concepts, we have implemented them in the Peis-Ecology NRS model. We report a number of experiments based on this implementation, which provide both quantitative and qualitative evaluations of its performance, reliability, and interoperability.

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Kandaswamy, Partheepan. "System on fabrics utilising distributed computing." Thesis, Loughborough University, 2018. https://dspace.lboro.ac.uk/2134/33381.

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The main vision of wearable computing is to make electronic systems an important part of everyday clothing in the future which will serve as intelligent personal assistants. Wearable devices have the potential to be wearable computers and not mere input/output devices for the human body. The present thesis focuses on introducing a new wearable computing paradigm, where the processing elements are closely coupled with the sensors that are distributed using Instruction Systolic Array (ISA) architecture. The thesis describes a novel, multiple sensor, multiple processor system architecture prototype based on the Instruction Systolic Array paradigm for distributed computing on fabrics. The thesis introduces new programming model to implement the distributed computer on fabrics. The implementation of the concept has been validated using parallel algorithms. A real-time shape sensing and reconstruction application has been implemented on this architecture and has demonstrated a physical design for a wearable system based on the ISA concept constructed from off-the-shelf microcontrollers and sensors. Results demonstrate that the real time application executes on the prototype ISA implementation thus confirming the viability of the proposed architecture for fabric-resident computing devices.

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Jingjing, Hao. "Distributed sensor fault detection and isolation over wireless sensor network." Doctoral thesis, Universite Libre de Bruxelles, 2017. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/254423.

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Wireless sensor networks (WSNs) can provide new methods for information gathering for a variety of applications. In order to ensure the network quality of service, the quality of the measurements has to be guaranteed. Distributed fault detection and isolation schemes are preferred to centralized solutions to diagnose faulty sensors in WSNs. Indeed the first approach avoids the need for a central node that collects information from every sensor node, and hence it limits complexity and energy cost while improving reliability.In the case of state estimation over distributed architectures, the sensor faults can be propagated in the network during the information exchanging process. To build a reliable state estimate one has to make sure that the measurements issued by the different sensors are fault free. That is one of the motivations to build a distributed fault detection and isolation (FDI) system that generates an alarm as soon as a measurement is subject to a fault (has drift, cdots ). In order to diagnose faults with small magnitude in wireless sensor networks, a systematic methodology to design and implement a distributed FDI system is proposed. It resorts to distinguishability measures to indicate the performance of the FDI system and to select the most suitable node(s) for information exchange in the network with a view to FDI. It allows one to determine the minimum amount of data to be exchanged between the different nodes for a given FDI performance. In this way, the specifications for FDI can be achieved while the communication and computation cost are kept as small as possible. The distributed FDI systems are designed both in deterministic and stochastic frameworks. They are based on the parity space approach that exploits spacial redundancy as well as temporal redundancy in the context of distributed schemes. The decision systems with the deterministic method and the stochastic method are designed not only to detect a fault but also to distinguish which fault is occurring in the network. A case study with a WSN is conducted to verify the proposed method. The network is used to monitor the temperature and humidity in a computer room. The distributed FDI system is validated both with simulated data and recorded data.
Doctorat en Sciences de l'ingénieur et technologie
info:eu-repo/semantics/nonPublished

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50

Lavassani, Mehrzad. "Reliable Information Exchange in IIoT : Investigation into the Role of Data and Data-Driven Modelling." Licentiate thesis, Mittuniversitetet, Avdelningen för informationssystem och -teknologi, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-34886.

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The concept of Industrial Internet of Things (IIoT) is the tangible building block for the realisation of the fourth industrial revolution. It should improve productivity, efficiency and reliability of industrial automation systems, leading to revenue growth in industrial scenarios. IIoT needs to encompass various disciplines and technologies to constitute an operable and harmonious system. One essential requirement for a system to exhibit such behaviour is reliable exchange of information. In industrial automation, the information life-cycle starts at the field level, with data collected by sensors, and ends at the enterprise level, where that data is processed into knowledge for business decision making. In IIoT, the process of knowledge discovery is expected to start in the lower layers of the automation hierarchy, and to cover the data exchange between the connected smart objects to perform collaborative tasks. This thesis aims to assist the comprehension of the processes for information exchange in IIoT-enabled industrial automation- in particular, how reliable exchange of information can be performed by communication systems at field level given an underlying wireless sensor technology, and how data analytics can complement the processes of various levels of the automation hierarchy. Furthermore, this work explores how an IIoT monitoring system can be designed and developed. The communication reliability is addressed by proposing a redundancy-based medium access control protocol for mission-critical applications, and analysing its performance regarding real-time and deterministic delivery. The importance of the data and the benefits of data analytics for various levels of the automation hierarchy are examined by suggesting data-driven methods for visualisation, centralised system modelling and distributed data streams modelling. The design and development of an IIoT monitoring system are addressed by proposing a novel three-layer framework that incorporates wireless sensor, fog, and cloud technologies. Moreover, an IIoT testbed system is developed to realise the proposed framework. The outcome of this study suggests that redundancy-based mechanisms improve communication reliability. However, they can also introduce drawbacks, such as poor link utilisation and limited scalability, in the context of IIoT. Data-driven methods result in enhanced readability of visualisation, and reduced necessity of the ground truth in system modelling. The results illustrate that distributed modelling can lower the negative effect of the redundancy-based mechanisms on link utilisation, by reducing the up-link traffic. Mathematical analysis reveals that introducing fog layer in the IIoT framework removes the single point of failure and enhances scalability, while meeting the latency requirements of the monitoring application. Finally, the experiment results show that the IIoT testbed works adequately and can serve for the future development and deployment of IIoT applications.
SMART (Smarta system och tjänster för ett effektivt och innovativt samhälle)

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Дисертації з теми "Sensor network and distributed systems"

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