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- Title
- Damage progression quantification and data robustness evaluation in self-powered sensors networks
- Creator
- Hasni, Hassene
- Date
- 2018
- Collection
- Electronic Theses & Dissertations
- Description
-
"This research proposes novel damage progression quantification and data robustness evaluation approaches, for structural health monitoring (SHM), using a new class of self-powered piezo-floating-gate (PFG) sensors. This system relies on harvesting the mechanical energy from structures through the direct effect of piezoelectricity. The operating power of the smart sensor and the data used for damage identification is harvested directly from the sensing signal induced by a piezoelectric...
Show more"This research proposes novel damage progression quantification and data robustness evaluation approaches, for structural health monitoring (SHM), using a new class of self-powered piezo-floating-gate (PFG) sensors. This system relies on harvesting the mechanical energy from structures through the direct effect of piezoelectricity. The operating power of the smart sensor and the data used for damage identification is harvested directly from the sensing signal induced by a piezoelectric transducer under dynamic loading. The developed models integrate structural simulations using finite element method (FEM) techniques, experimental studies, and statistical and artificial intelligence (AI) methods. In this work, the performance of the sensing system in identifying damage is investigated for various damage scenarios based on numerical and experimental studies. Both steel and pavement structures are studied. A new surface sensing approach for detecting bottom-up cracks in asphalt concrete (AC) pavement is proposed. Two types of self-powered wireless sensors are investigated in this research. Different data interpretation techniques are developed for each type of sensor. The data are obtained from finite element simulations, or experimental measurement, and are fitted to probability distributions to define initial damage indicators. Sensor fusion models are developed based on the concept of group-effect of sensors, in order to increase the damage detection resolution of individual sensors. Probabilistic neural network (PNN) and support vector machine (SVM) methods are used to improve the accuracy of the proposed damage identification methods for the case of multi-class damage progression. The proposed work is divided into four main parts: (i) Damage identification in steel structures using data from a uniform PFG sensor, (ii) Damage detection in steel and pavement structures using a non-uniform PFG sensor, (iii) Damage detection and localization in steel frame structures using hybrid network of self-powered strain and vibration sensors, and, (iv) a field demonstration of the new technology on the Mackinac Bridge in Michigan. The cases of the U10W gusset plate of the I-35W bridge in Minneapolis, MN, a steel girder, a steel plate under compaction tension mode, and an AC beam under three-point bending configuration are investigated. A surface sensing approach to detect bottom-up cracking in AC pavement under dynamic moving load is also proposed. This approach is based on interpreting the data of a surface-mounted network of sensors. Moreover, a hybrid network of strain and vibration-based sensors is used to detect damage in bolted steel frames. The objective is to establish a local-to-global strategy for damage identification in frames. Data fusion models combined with AI classifiers are developed. Uncertainty analysis is performed to verify the performance of the sensors under different noise levels."--Pages ii-iii.
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- Title
- Cost-aware secure protocol design and analysis
- Creator
- Tang, Di
- Date
- 2015
- Collection
- Electronic Theses & Dissertations
- Description
-
The recent technological progresses make sensor networks feasible to be widely used in both military and civilian applications. The nature of such networks makes energy consumption, communication delay and security the most essential issues for wireless sensor networks. However, these issues may be conflicting with each other. The existing works generally try to optimize one of these key issues without providing sufficient diversity and flexibility of various other requirements in protocol...
Show moreThe recent technological progresses make sensor networks feasible to be widely used in both military and civilian applications. The nature of such networks makes energy consumption, communication delay and security the most essential issues for wireless sensor networks. However, these issues may be conflicting with each other. The existing works generally try to optimize one of these key issues without providing sufficient diversity and flexibility of various other requirements in protocol design. In this dissertation, we investigate the relationship and design trade-offs among these conflicting issues.To deal with the lifetime optimization and security issues, we propose a novel secure and efficient Cost-Aware SEcure Routing (CASER) protocol to address them through two adjustable parameters: energy balance control (EBC) and security level to enforce energy balance and increase lifetime and determine the probabilistic distribution of random walking that provides routing security. We derive a tight numerical formula to quantitatively estimate the routing efficiency through the number of routing hops for a given routing security level. We also prove that CASER scheme can provide provable security under the quantitative security measurement criteria. Simulation results also show that the proposed CASER scheme can provide an excellent balance between routing efficiency and security while extending the network lifetime.We then discover that the energy consumption is severely disproportional to the uniform energy deployment for the given network topology. To solve this problem, we propose an efficient non-uniform energy deployment strategy to optimize the network lifetime and increase the message delivery ratio under the same energy resource and security requirements. Our theoretical analysis and OPNET simulation results demonstrate that the updated CASER protocol can provide an excellent trade-off between routing efficiency and energy consumption, while significantly extending the lifetime of the sensor networks in all scenarios. For the non-uniform energy deployment, our analysis shows that we can increase the lifetime and the total number of messages that can be delivered by more than four times under the same energy deployment, while achieving a high message delivery ratio and preventing routing traceback attacks.In WSNs, congestion introduces not only buffer overflow, but also communication delay for forwarding messages from the source node to the sink. We propose a novel congestion-aware routing (CAR) scheme to reduce the end-to-end communication delay while increasing network throughput. CAR employs two routing strategies, shortest path routing strategy and congestion-aware strategy, to achieve a trade-off between energy efficiency and communication delay. The OPNET simulation results demonstrate that the proposed routing scheme can reduce the end-to-end communication delay by 50% while increasing the network throughput by more than two times in our settings.People-centric urban sensing is envisioned as a novel urban sensing paradigm. Security, communication delay and delivery ratio are essential design issues in people-centric urban sensing networks. To address these three issues concurrently, we propose a novel delay-aware privacy preserving (DAPP) transmission scheme based on a combination of two-phase forwarding and secret sharing. The two-phase forwarding method detaches connection between the application data server and the source nodes, which renders it infeasible for the application data server to estimate source node identities. The underlying secret sharing scheme and dynamic pseudonym ensure confidentiality of the collected data and anonymity of participating users. DAPP provides a framework to achieve a design trade-off among security, communication delay and delivery ratio. The security analysis demonstrates that DAPP can preserve location privacy while defending against side information attacks. Theoretical analysis and simulation results show that our proposed algorithms can provide a flexible and diverse security design option for routing and data forwarding algorithm design.
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- Title
- Cost-aware routing protocols for location-privacy and efficiency in wireless sensor networks
- Creator
- Lightfoot, Leron J.
- Date
- 2015
- Collection
- Electronic Theses & Dissertations
- Description
-
Wireless sensor networks (WSNs) can provide the world with a technology for real-time event monitoring for both military and civilian applications. One of the primary concerns that hinders the successful deployment of wireless sensor networks is how to provide adequate source and destination nodes location privacy. The privacy of the location is vital and highly jeopardized by the usage of wireless communications. While message content privacy can be ensured through message encryption, it is...
Show moreWireless sensor networks (WSNs) can provide the world with a technology for real-time event monitoring for both military and civilian applications. One of the primary concerns that hinders the successful deployment of wireless sensor networks is how to provide adequate source and destination nodes location privacy. The privacy of the location is vital and highly jeopardized by the usage of wireless communications. While message content privacy can be ensured through message encryption, it is much more difficult to adequately address the location privacy issue. For WSNs, location privacy service is further complicated by the fact that sensors consist of low-cost and energy efficient radio devices. Therefore, using computationally intensive cryptographic algorithms (such as public-key cryptosystems) and large scale broadcasting-based protocols are not suitable for WSNs.Many protocols have been proposed to provide location privacy but most of them are based on public-key cryptosystems, while others are either energy inefficient or have certain security flaws. After analyzing the security weaknesses of the existing schemes, we propose several creative and secure energy-aware routing protocols that can address the location privacy issue in WSNs. For source-location privacy, we propose 3 schemes. The first scheme routes each message to a randomly selected intermediate node (RSIN) before it is transmitted to the SINK node. However, this scheme can only provide local source-location privacy. In the second scheme, a network mixing ring (NMR) is proposed to provide network-level source-location privacy. The third scheme achieves network-level source-location privacy through a technique we call the Sink Toroidal Region (STaR) routing. For destination-location privacy, we propose the Bubble routing protocol and a series of R-STaR routing protocols. For each of these routing schemes, both security analysis using quantitative measurements and simulation results show that the proposed protocols are secure and energy-efficient.While providing location privacy is vital, prolonging the lifetime of the network can be a very essential component as well. In this dissertation, we propose a cluster-based energy-aware routing scheme, called Quad-Region Cluster-Head Selection (Q-ReCHS), which will prolong the network lifetime by evenly distributing the energy load among all the nodes. Our extensive simulation results on cluster-based routing demonstrates that our proposed Q-ReCHS scheme can out perform many of the existing schemes.
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- Title
- Assessment of ultrasonic guided wave inspection methods for structural health monitoring
- Creator
- Dib, Gerges
- Date
- 2014
- Collection
- Electronic Theses & Dissertations
- Description
-
Structural health monitoring (SHM) has the potential to significantly increase safety and reduce manufacturing and maintenance costs of industrial structures. The use of piezoelectric material such as Lead-Zirconate-Titanate (PZT) in exciting and sensing ultrasonic guidedwaves for damage detection has become popular since its allows the rapid inspection of large areas in a structure using non-intrusive sensors. Ultrasonic guided waves interact with discontinuities in the structure, giving...
Show moreStructural health monitoring (SHM) has the potential to significantly increase safety and reduce manufacturing and maintenance costs of industrial structures. The use of piezoelectric material such as Lead-Zirconate-Titanate (PZT) in exciting and sensing ultrasonic guidedwaves for damage detection has become popular since its allows the rapid inspection of large areas in a structure using non-intrusive sensors. Ultrasonic guided waves interact with discontinuities in the structure, giving information about the potential presence of a damage, its size and location.The main concerns about using such methods is that PZT sensors and guided waves are affected by environmental conditions. The performance of the PZT sensors, in terms of their ability to detect damage, degrades over time and varies depending on current environmental conditions and surrounding, resulting in inconsistent measurements. This work gives a novel formulation of a model-based probability of detection method, which is able to quantifythe performance of guided wave inspection in a stochastically varying environment. An analytically and experimentally verified finite element model is used to generate data that represent the effects of varying environmental conditions. Then the stochastic approachis used to evaluate the probability of detection of cracks in riveted aluminum plates and delaminations in composite plates. Also, the performance of guided wave imaging algorithms under degrading PZT conditions is examined.Another concern is the ability to transfer data from the PZT sensors, which are per-manently located on the structure, to a computer where the data could be processed in real-time or near real-time. Wireless sensor networks (WSN) use low footprint smart sensor nodes that are permanently mounted on the structure. The sensor nodes have their own power supply and wireless communication devices to communicate with other sensor nodes or a base station. Wireless sensor node for guided waves require an actuation interfacesand high frequency sampling of the guided wave measurements. A proof-of-concept wireless sensor node prototype is developed for the data acquisition and actuation using PZT sensorsand guided waves.
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- Title
- Analytical and quantitative characterization of wireless sensor networks
- Creator
- Ilyas, Muhammad Usman
- Date
- 2009
- Collection
- Electronic Theses & Dissertations
- Title
- Advanced data analysis framework for damage identification in civil infrastructure based on self-powered sensing
- Creator
- Alavi, Amir Hossein
- Date
- 2016
- Collection
- Electronic Theses & Dissertations
- Description
-
"This interdisciplinary research proposes an advanced data analysis framework for civil infrastructure/structural health monitoring (I/SHM) based on a pioneering self-powered sensing technology. The current work characterizes the performance of a fairly new class of self-powered sensors for specific application problems with complex behavior. The proposed health monitoring systems are established through the integration of statistical, artificial intelligence and finite element methods....
Show more"This interdisciplinary research proposes an advanced data analysis framework for civil infrastructure/structural health monitoring (I/SHM) based on a pioneering self-powered sensing technology. The current work characterizes the performance of a fairly new class of self-powered sensors for specific application problems with complex behavior. The proposed health monitoring systems are established through the integration of statistical, artificial intelligence and finite element methods. Different infrastructure systems with various damage types are analyzed. A new probabilistic artificial intelligence-based damage detection technique is developed that hybridizes genetic programming and logistic regression algorithms. The proposed multi-class classification system assigns probabilities to model scores to detect damage progression. A probabilistic neural network method based on Bayesian theory is further introduced to improve the damage detection accuracy. Data obtained from the finite element simulations and experimental study of hybrid sensor networks is used to calibrate the data interpretation algorithms. The network architecture comprises self-powered sensors that use the electrical energy directly harvested by piezoelectric ceramic Lead Zirconate Titanate (PZT) transducers. The beauty of this so-called self-powered monitoring system is that the operating power for the smart sensors directly comes from the signal being monitored. An advantage of using these sensors is that there is no need to directly measure the absolute value of strain in order to estimate damage. In fact, the proposed self-sustained sensing systems use the sensor output to relate the variation rate of strain distributions to the rate of damage. The proposed data analysis framework consists of multilevel strategies for structural/infrastructure damage identification through: (a) analysis of individual self-powered strain sensors, (b) data fusion in a network of self-powered strain sensors, and (c) data analysis in a hybrid network of self-powered accelerometer and strain sensors. For each of these levels, several damage indicator features are extracted upon the simulation of the compressed data stored in memory chips of the self-powered sensors. A new data fusion concept based on the effect of group of sensors, termed as "group effect", is proposed. The goal is to improve the damage detection performance through spatial measurements over structures. Moreover, combination of the data from a network of accelerometer and strain sensors results in developing an integrated global-local damage detection approach. The investigated cases are crack growth detection in steel plates under a uniaxial tension mode, distortion-induced fatigue cracking in steel bridge girders, continuous health monitoring of pavement systems, failure of simply supported beam under three-point bending, and failure of gusset plate of the I-35W highway bridge in Minneapolis, Minnesota. 3D dynamic finite element models are developed for each of the cases. The experimental studies are carried out on a steel plate subjected to an in-plane tension, a steel plate with bolted connections, and on asphalt concrete specimens in three-point bending mode. PZT-5A ceramic discs and PZT-5H bimorph accelerometers are placed on the surface of the plates to measure the delivered voltage in each damage phase. For the asphalt experiments, a new miniaturized spherical packaging system is designed and tested to protect the PZT ceramic discs embedded inside the specimen. Uncertainty analyses are performed through the contamination of the damage indicator features with different noise levels. The results indicate that the proposed I/SHM systems are efficiently capable of detecting different damage states in spite of high-level noise contamination."--Pages ii-iii.
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- Title
- A progressive reliability framework for wireless sensor networks
- Creator
- Qaisar, Saad Bin
- Date
- 2009
- Collection
- Electronic Theses & Dissertations