174 research outputs found

    Analysis of Passive Magnetic Inspection Signals Using the Haar Wavelet and Asymmetric Gaussian Chirplet Model (AGCM)

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    Nowadays, Non-Destructive Testing (NDT) techniques are an essential foundation of infrastructure retrofit and rehabilitation plans, mainly due to the huge amount of construction, as well as the high cost of demolition and reconstruction. Modern NDT methods are moving toward automated detection methods to increase the speed and probability of detection, which enlarges the size of inspection data and raises the demand for new data analysis methods. NDT methods are divided into two main groups; active and passive. The external potentials are discharged into an object in an active method, and then the reflection wave is recorded. However, the passive methods use the self-created magnetic field of the object. Therefore, the magnetic value of ferromagnetic material in a passive method is less than the magnetic value of an active method, and defects and anomalies detection needs more variety of functional signal processing methods. The Passive Magnetic Inspection (PMI) method, as an NDT-passive technology, is used in this thesis for ferromagnetic materials quantitative assessment. The success of the PMI depends on the detection of anomalies of the passive magnetic signals, which is different for every single test. This research aims to develop appropriate signal processing methods to enhance the PMI quality of defect detection in ferromagnetic materials. This thesis has two main parts and presents two computer-based inspection data analysis methods based on the Haar wavelet and the Asymmetric Gaussian Chriplet Model (AGCM). The Passive Magnetic Inspection method (PMI) is used to scan ferromagnetic materials and produce the raw magnetic data analyzed by the Haar wavelet and AGCM. The first part of this study describes the Haar wavelet method for rebar defect detection. The Haar wavelet is used to analyze the PMI magnetic data of the embedded reinforcement steel rebar. The corrugated surface of reinforcing steel makes the detection of defects harder than in flat plates. The up and down shape of the Haar wavelet function can filter the repeating corrugations effect of steel rebars on the PMI signal and thereby better identify the defects. Toogood Pond Dam piers’ rebar defects, as a case study, were detected using the Haar wavelet analysis and verified by the Absolute Gradient (AG) method using visual comparison of the resultant signals and the correlation coefficient. The predicted number of points with a rebar area loss higher than 4% is generally the same with the AG and the Haar wavelet methods. The mean correlation coefficient between the signals analyzed using the AG and the Haar wavelet for all rebars is 0.8. In the second part of this study the use of the AGCM to simulate PMI signals is investigated. Three rail samples were scanned to extract a three-dimensional magnetic field along specific PMI transit lines of each sample for the AGCM simulations. Errors, defined as the absolute value of the difference between signal and simulation, were considered as a measure of simulation accuracy in each direction. The samples’ lengths differed, therefore error values were normalized with respect to the length to scale data for the three samples. The Simulation Error Factor (SEF) was used to measure the error and sample 3 showed the lower value. Finally, statistical properties of the samples' SEF, such as standard deviation and covariance, were evaluated, and the best distribution was fitted to each of the data sets based on the Probability Paper Plot (PPP) method. The Log-Normal probability distribution demonstrated the best compatibility with SEF values. These distributions and statistical properties help to detect outlier data for future data sets and to identify defects

    IoT in smart communities, technologies and applications.

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    Internet of Things is a system that integrates different devices and technologies, removing the necessity of human intervention. This enables the capacity of having smart (or smarter) cities around the world. By hosting different technologies and allowing interactions between them, the internet of things has spearheaded the development of smart city systems for sustainable living, increased comfort and productivity for citizens. The Internet of Things (IoT) for Smart Cities has many different domains and draws upon various underlying systems for its operation, in this work, we provide a holistic coverage of the Internet of Things in Smart Cities by discussing the fundamental components that make up the IoT Smart City landscape, the technologies that enable these domains to exist, the most prevalent practices and techniques which are used in these domains as well as the challenges that deployment of IoT systems for smart cities encounter and which need to be addressed for ubiquitous use of smart city applications. It also presents a coverage of optimization methods and applications from a smart city perspective enabled by the Internet of Things. Towards this end, a mapping is provided for the most encountered applications of computational optimization within IoT smart cities for five popular optimization methods, ant colony optimization, genetic algorithm, particle swarm optimization, artificial bee colony optimization and differential evolution. For each application identified, the algorithms used, objectives considered, the nature of the formulation and constraints taken in to account have been specified and discussed. Lastly, the data setup used by each covered work is also mentioned and directions for future work have been identified. Within the smart health domain of IoT smart cities, human activity recognition has been a key study topic in the development of cyber physical systems and assisted living applications. In particular, inertial sensor based systems have become increasingly popular because they do not restrict users’ movement and are also relatively simple to implement compared to other approaches. Fall detection is one of the most important tasks in human activity recognition. With an increasingly aging world population and an inclination by the elderly to live alone, the need to incorporate dependable fall detection schemes in smart devices such as phones, watches has gained momentum. Therefore, differentiating between falls and activities of daily living (ADLs) has been the focus of researchers in recent years with very good results. However, one aspect within fall detection that has not been investigated much is direction and severity aware fall detection. Since a fall detection system aims to detect falls in people and notify medical personnel, it could be of added value to health professionals tending to a patient suffering from a fall to know the nature of the accident. In this regard, as a case study for smart health, four different experiments have been conducted for the task of fall detection with direction and severity consideration on two publicly available datasets. These four experiments not only tackle the problem on an increasingly complicated level (the first one considers a fall only scenario and the other two a combined activity of daily living and fall scenario) but also present methodologies which outperform the state of the art techniques as discussed. Lastly, future recommendations have also been provided for researchers

    Low-Cost Sensors and Biological Signals

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    Many sensors are currently available at prices lower than USD 100 and cover a wide range of biological signals: motion, muscle activity, heart rate, etc. Such low-cost sensors have metrological features allowing them to be used in everyday life and clinical applications, where gold-standard material is both too expensive and time-consuming to be used. The selected papers present current applications of low-cost sensors in domains such as physiotherapy, rehabilitation, and affective technologies. The results cover various aspects of low-cost sensor technology from hardware design to software optimization

    NASA SBIR abstracts of 1990 phase 1 projects

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    The research objectives of the 280 projects placed under contract in the National Aeronautics and Space Administration (NASA) 1990 Small Business Innovation Research (SBIR) Phase 1 program are described. The basic document consists of edited, non-proprietary abstracts of the winning proposals submitted by small businesses in response to NASA's 1990 SBIR Phase 1 Program Solicitation. The abstracts are presented under the 15 technical topics within which Phase 1 proposals were solicited. Each project was assigned a sequential identifying number from 001 to 280, in order of its appearance in the body of the report. The document also includes Appendixes to provide additional information about the SBIR program and permit cross-reference in the 1990 Phase 1 projects by company name, location by state, principal investigator, NASA field center responsible for management of each project, and NASA contract number

    Engineering Dynamics and Life Sciences

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    From Preface: This is the fourteenth time when the conference “Dynamical Systems: Theory and Applications” gathers a numerous group of outstanding scientists and engineers, who deal with widely understood problems of theoretical and applied dynamics. Organization of the conference would not have been possible without a great effort of the staff of the Department of Automation, Biomechanics and Mechatronics. The patronage over the conference has been taken by the Committee of Mechanics of the Polish Academy of Sciences and Ministry of Science and Higher Education of Poland. It is a great pleasure that our invitation has been accepted by recording in the history of our conference number of people, including good colleagues and friends as well as a large group of researchers and scientists, who decided to participate in the conference for the first time. With proud and satisfaction we welcomed over 180 persons from 31 countries all over the world. They decided to share the results of their research and many years experiences in a discipline of dynamical systems by submitting many very interesting papers. This year, the DSTA Conference Proceedings were split into three volumes entitled “Dynamical Systems” with respective subtitles: Vibration, Control and Stability of Dynamical Systems; Mathematical and Numerical Aspects of Dynamical System Analysis and Engineering Dynamics and Life Sciences. Additionally, there will be also published two volumes of Springer Proceedings in Mathematics and Statistics entitled “Dynamical Systems in Theoretical Perspective” and “Dynamical Systems in Applications”

    Proceedings of the 2018 Canadian Society for Mechanical Engineering (CSME) International Congress

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    Published proceedings of the 2018 Canadian Society for Mechanical Engineering (CSME) International Congress, hosted by York University, 27-30 May 2018

    Autocalibrating vision guided navigation of unmanned air vehicles via tactical monocular cameras in GPS denied environments

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    This thesis presents a novel robotic navigation strategy by using a conventional tactical monocular camera, proving the feasibility of using a monocular camera as the sole proximity sensing, object avoidance, mapping, and path-planning mechanism to fly and navigate small to medium scale unmanned rotary-wing aircraft in an autonomous manner. The range measurement strategy is scalable, self-calibrating, indoor-outdoor capable, and has been biologically inspired by the key adaptive mechanisms for depth perception and pattern recognition found in humans and intelligent animals (particularly bats), designed to assume operations in previously unknown, GPS-denied environments. It proposes novel electronics, aircraft, aircraft systems, systems, and procedures and algorithms that come together to form airborne systems which measure absolute ranges from a monocular camera via passive photometry, mimicking that of a human-pilot like judgement. The research is intended to bridge the gap between practical GPS coverage and precision localization and mapping problem in a small aircraft. In the context of this study, several robotic platforms, airborne and ground alike, have been developed, some of which have been integrated in real-life field trials, for experimental validation. Albeit the emphasis on miniature robotic aircraft this research has been tested and found compatible with tactical vests and helmets, and it can be used to augment the reliability of many other types of proximity sensors

    A sense of self for power side-channel signatures: instruction set disassembly and integrity monitoring of a microcontroller system

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    Cyber-attacks are on the rise, costing billions of dollars in damages, response, and investment annually. Critical United States National Security and Department of Defense weapons systems are no exception, however, the stakes go well beyond financial. Dependence upon a global supply chain without sufficient insight or control poses a significant issue. Additionally, systems are often designed with a presumption of trust, despite their microelectronics and software-foundations being inherently untrustworthy. Achieving cybersecurity requires coordinated and holistic action across disciplines commensurate with the specific systems, mission, and threat. This dissertation explores an existing gap in low-level cybersecurity while proposing a side-channel based security monitor to support attack detection and the establishment of trusted foundations for critical embedded systems. Background on side-channel origins, the more typical side-channel attacks, and microarchitectural exploits are described. A survey of related side-channel efforts is provided through side-channel organizing principles. The organizing principles enable comparison of dissimilar works across the side-channel spectrum. We find that the maturity of existing side-channel security monitors is insufficient, as key transition to practice considerations are often not accounted for or resolved. We then document the development, maturation, and assessment of a power side-channel disassembler, Time-series Side-channel Disassembler (TSD), and extend it for use as a security monitor, TSD-Integrity Monitor (TSD-IM). We also introduce a prototype microcontroller power side-channel collection fixture, with benefits to experimentation and transition to practice. TSD-IM is finally applied to a notional Point of Sale (PoS) application for proof of concept evaluation. We find that TSD and TSD-IM advance state of the art for side-channel disassembly and security monitoring in open literature. In addition to our TSD and TSD-IM research on microcontroller signals, we explore beneficial side-channel measurement abstractions as well as the characterization of the underlying microelectronic circuits through Impulse Signal Analysis (ISA). While some positive results were obtained, we find that further research in these areas is necessary. Although the need for a non-invasive, on-demand microelectronics-integrity capability is supported, other methods may provide suitable near-term alternatives to ISA

    Wearable and BAN Sensors for Physical Rehabilitation and eHealth Architectures

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    The demographic shift of the population towards an increase in the number of elderly citizens, together with the sedentary lifestyle we are adopting, is reflected in the increasingly debilitated physical health of the population. The resulting physical impairments require rehabilitation therapies which may be assisted by the use of wearable sensors or body area network sensors (BANs). The use of novel technology for medical therapies can also contribute to reducing the costs in healthcare systems and decrease patient overflow in medical centers. Sensors are the primary enablers of any wearable medical device, with a central role in eHealth architectures. The accuracy of the acquired data depends on the sensors; hence, when considering wearable and BAN sensing integration, they must be proven to be accurate and reliable solutions. This book is a collection of works focusing on the current state-of-the-art of BANs and wearable sensing devices for physical rehabilitation of impaired or debilitated citizens. The manuscripts that compose this book report on the advances in the research related to different sensing technologies (optical or electronic) and body area network sensors (BANs), their design and implementation, advanced signal processing techniques, and the application of these technologies in areas such as physical rehabilitation, robotics, medical diagnostics, and therapy

    Intelligent Sensor Networks

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    In the last decade, wireless or wired sensor networks have attracted much attention. However, most designs target general sensor network issues including protocol stack (routing, MAC, etc.) and security issues. This book focuses on the close integration of sensing, networking, and smart signal processing via machine learning. Based on their world-class research, the authors present the fundamentals of intelligent sensor networks. They cover sensing and sampling, distributed signal processing, and intelligent signal learning. In addition, they present cutting-edge research results from leading experts
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