Dynamic modeling and characterization of magnetic hybrid films of polyvinyl butyral/iron oxide nanoparticles (PVB/Fe₂O₃) devoted to microactuators.

This thesis was accomplished in a dual-degree modality between the consolidated group of Synthesis and Characterization of Materials ꟷFacultad de Ingeniería Mecánica y Eléctrica (FIME), Universidad Autónoma de Nuevo León (UANL), México, and the research group of Methodologies for Automatic Control and for Design of Mechatronic Systems (MACS), department of Automatic Control and Micro-Mechatronic Systems ꟷ FEMTO-ST institute, Université Bourgogne Franche-Comté (UBFC), France

Investigations on corrosion monitor reliability, calibration, and coverage

Thickness loss due to internal corrosion and erosion is a critical issue in ferromagnetic steel structures that can cause catastrophic failures. Ultrasonic thickness gauges are widely used for the detection of wall thickness. Recently permanently installed ultrasonic sensors have become popular for the inspection of areas suspected to undergo wall thickness loss. However, these are limited by the high cost and requirement of coupling agents. To address these problems, a novel cost-effective, and smart corrosion monitor based on the magnetic eddy current technique is developed in this research. The performance and reliability of the monitor to track internal wall thickness loss is tested successfully through accelerated and real-life aging corrosion tests. Due to the handling and safety issues associated with the powerful magnets in magnetic techniques, a particle swarm-based optimisation method is proposed and validated through two test cases. The results indicate that the area of the magnetic excitation circuit could be reduced by 38% without compromising the sensitivity. The reliability of the corrosion monitor is improved by utilising the active redundancy approach to identify and isolate faults in sensors. A real-life aging test is conducted for eight months in an ambient environment through an accelerated corrosion setup. The results obtained from the two corrosion monitors confirm that the proposed corrosion monitor is reliable for tracking the thickness loss. The corrosion monitor is found to be stable against environmental variations. A new in-situ calibration method based on zero-crossing frequency feature is introduced to evaluate the in-situ relative permeability. The thickness of the test specimen could be estimated with an accuracy of ± 0.6 mm. The series of studies conducted in the project reveal that the magnetic corrosion monitor has the capability to detect and quantify uniform wall thickness loss reliably

Motion-based remote control device for interaction with multimedia content

This dissertation describes the development and implementation of techniques to enhance the accuracy of low-complexity lters, making them suitable for remote control devices in consumer electronics. The evolution veri ed in the last years, on multimedia contents, available for consumers in Smart TVs and set-top-boxes, is not raising the expected interest from users, and one of the pointed reasons for this nding is the user interface. Although most current pointing devices rely on relative rotation increments, absolute orientation allows for a more intuitive use and interaction. This possibility is explored in this work as well as the interaction with multimedia contents through gestures. Classical accurate fusion algorithms are computationally intensive, therefore their implementation in low-energy consumption devices is a challenging task. To tackle this problem, a performance study was carried, comparing a relevant set of professional commercial of-the-shelf units, with the developed low-complexity lters in state-of-the-art Magnetic, Angular Rate, Gravity (MARG) sensors. Part of the performance evaluation tests are carried out under harsh conditions to observe the algorithms response in a nontrivial environment. The results demonstrate that the implementation of low-complexity lters using low-cost sensors, can provide an acceptable accuracy in comparison with the more complex units/ lters. These results pave the way for faster adoption of absolute orientation-based pointing devices in interactive multimedia applications, which includes hand-held, battery-operated devices

Design and Testing of a Multi-Sensor Pedestrian Location and Navigation Platform

Navigation and location technologies are continually advancing, allowing ever higher accuracies and operation under ever more challenging conditions. The development of such technologies requires the rapid evaluation of a large number of sensors and related utilization strategies. The integration of Global Navigation Satellite Systems (GNSSs) such as the Global Positioning System (GPS) with accelerometers, gyros, barometers, magnetometers and other sensors is allowing for novel applications, but is hindered by the difficulties to test and compare integrated solutions using multiple sensor sets. In order to achieve compatibility and flexibility in terms of multiple sensors, an advanced adaptable platform is required. This paper describes the design and testing of the NavCube, a multi-sensor navigation, location and timing platform. The system provides a research tool for pedestrian navigation, location and body motion analysis in an unobtrusive form factor that enables in situ data collections with minimal gait and posture impact. Testing and examples of applications of the NavCube are provided

Magnetic Flux Leakage techniques for detecting corrosion of pipes

Oil and gas pipelines are subjected to corrosion due to harsh environmental conditions as in refinery and thermal power plants. Interesting problems such as internal and external corrosion, emerging from the increasing demand for pipeline protection have prompted this study. Thus, early detection of faults in pipes is essential to avoid disastrous outcomes. The research work presented in this thesis comprises investigations into the use of magnetic flux leakage (MFL) testing for pipe in extreme (underwater and high temperature) conditions. The design of a coil sensor (ferrite core with coil) with a magnetic circuit is carried out for high temperature conditions. The sensor thus developed lays the ground for non-destructive evaluation (NDE) of flaws in pipes through the MFL technique. The research focusses on the detection and characterization of MFL distribution caused by the loss of metal in ferromagnetic steel pipes. Experimental verifications are initially conducted with deeply rusted pipe samples of varying thicknesses in air. AlNiCo magnets are used along with Giant Magneto Resistance (GMR) sensor (AA002-02). The experiment is further repeated for saltwater conditions in relation to varying electrical conductivity with radio frequency identification (RFID) technique. A further study carried out in the research is the correlation between magnetic and underwater data communication. The study has resulted in the development and experimental evaluation of a coil sensor with its magnetic response at room and high temperatures. This makes the system effective under high temperature conditions where corrosion metal loss needs to be determined

Magnetic Flux Leakage techniques for detecting corrosion of pipes

Oil and gas pipelines are subjected to corrosion due to harsh environmental conditions as in refinery and thermal power plants. Interesting problems such as internal and external corrosion, emerging from the increasing demand for pipeline protection have prompted this study. Thus, early detection of faults in pipes is essential to avoid disastrous outcomes. The research work presented in this thesis comprises investigations into the use of magnetic flux leakage (MFL) testing for pipe in extreme (underwater and high temperature) conditions. The design of a coil sensor (ferrite core with coil) with a magnetic circuit is carried out for high temperature conditions. The sensor thus developed lays the ground for non-destructive evaluation (NDE) of flaws in pipes through the MFL technique. The research focusses on the detection and characterization of MFL distribution caused by the loss of metal in ferromagnetic steel pipes. Experimental verifications are initially conducted with deeply rusted pipe samples of varying thicknesses in air. AlNiCo magnets are used along with Giant Magneto Resistance (GMR) sensor (AA002-02). The experiment is further repeated for saltwater conditions in relation to varying electrical conductivity with radio frequency identification (RFID) technique. A further study carried out in the research is the correlation between magnetic and underwater data communication. The study has resulted in the development and experimental evaluation of a coil sensor with its magnetic response at room and high temperatures. This makes the system effective under high temperature conditions where corrosion metal loss needs to be determined

Machine learning techniques for identification using mobile and social media data

Networked access and mobile devices provide near constant data generation and collection. Users, environments, applications, each generate different types of data; from the voluntarily provided data posted in social networks to data collected by sensors on mobile devices, it is becoming trivial to access big data caches. Processing sufficiently large amounts of data results in inferences that can be characterized as privacy invasive. In order to address privacy risks we must understand the limits of the data exploring relationships between variables and how the user is reflected in them. In this dissertation we look at data collected from social networks and sensors to identify some aspect of the user or their surroundings. In particular, we find that from social media metadata we identify individual user accounts and from the magnetic field readings we identify both the (unique) cellphone device owned by the user and their course-grained location. In each project we collect real-world datasets and apply supervised learning techniques, particularly multi-class classification algorithms to test our hypotheses. We use both leave-one-out cross validation as well as k-fold cross validation to reduce any bias in the results. Throughout the dissertation we find that unprotected data reveals sensitive information about users. Each chapter also contains a discussion about possible obfuscation techniques or countermeasures and their effectiveness with regards to the conclusions we present. Overall our results show that deriving information about users is attainable and, with each of these results, users would have limited if any indication that any type of analysis was taking place

Security of GPS/INS based On-road Location Tracking Systems

Location information is critical to a wide-variety of navigation and tracking applications. Today, GPS is the de-facto outdoor localization system but has been shown to be vulnerable to signal spoofing attacks. Inertial Navigation Systems (INS) are emerging as a popular complementary system, especially in road transportation systems as they enable improved navigation and tracking as well as offer resilience to wireless signals spoofing, and jamming attacks. In this paper, we evaluate the security guarantees of INS-aided GPS tracking and navigation for road transportation systems. We consider an adversary required to travel from a source location to a destination, and monitored by a INS-aided GPS system. The goal of the adversary is to travel to alternate locations without being detected. We developed and evaluated algorithms that achieve such goal, providing the adversary significant latitude. Our algorithms build a graph model for a given road network and enable us to derive potential destinations an attacker can reach without raising alarms even with the INS-aided GPS tracking and navigation system. The algorithms render the gyroscope and accelerometer sensors useless as they generate road trajectories indistinguishable from plausible paths (both in terms of turn angles and roads curvature). We also designed, built, and demonstrated that the magnetometer can be actively spoofed using a combination of carefully controlled coils. We implemented and evaluated the impact of the attack using both real-world and simulated driving traces in more than 10 cities located around the world. Our evaluations show that it is possible for an attacker to reach destinations that are as far as 30 km away from the true destination without being detected. We also show that it is possible for the adversary to reach almost 60-80% of possible points within the target region in some cities

Smart Materials and Devices for Energy Harvesting

This book is devoted to energy harvesting from smart materials and devices. It focusses on the latest available techniques recently published by researchers all over the world. Energy Harvesting allows otherwise wasted environmental energy to be converted into electric energy, such as vibrations, wind and solar energy. It is a common experience that the limiting factor for wearable electronics, such as smartphones or wearable bands, or for wireless sensors in harsh environments, is the finite energy stored in onboard batteries. Therefore, the answer to the battery “charge or change” issue is energy harvesting because it converts the energy in the precise location where it is needed. In order to achieve this, suitable smart materials are needed, such as piezoelectrics or magnetostrictives. Moreover, energy harvesting may also be exploited for other crucial applications, such as for the powering of implantable medical/sensing devices for humans and animals. Therefore, energy harvesting from smart materials will become increasingly important in the future. This book provides a broad perspective on this topic for researchers and readers with both physics and engineering backgrounds