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<p> Location privacy has been one of the greatest threats in wireless systems. The utilization of k-anonymity in Wireless Sensor Networks (WSNs) protects the location privacy. This characteristic feature enables the server to receive aggregate k-anonymized locations of internally connected sensor nodes. These k-anonymized locations are comprised of, a minimum of k persons. Nevertheless, an intruder model is used to high point the readiness of privacy risks in overlapping aggregate locations because an adversary can deduce the overlapping areas contained in an area with less than k persons whose requirement violates k-anonymity privacy. Hence, a reciprocal protocol (REAL) is used for establishing location privacy in Wireless Sensor Networks (WSNs). </p><p> The sensor nodes organize a group of non-overlapping areas and k-anonymized locations into sensing areas. To overcome the privacy threats in REAL, a process state transition is designed with a time delay mechanism that provides accuracy of the messages received and a locking mechanism is designed to enhance reciprocity property. The generation of an error-free query reply and securing location privacy and decreasing computational and communication costs is achieved by the experimental analysis of the REAL protocol .</p>

<p> Wireless Sensor Networks (WSN) consist of a large number of battery-powered devices (nodes), which transmit their data to a central node called the sink. Multi-hopping techniques are used to deliver the sensed data to the sink. The nodes that are close to the sink receive high volume of data from the rest of the network, and they have to forward these data to the sink. As a result, these nearby nodes drain their batteries and die quicker than other nodes in the network. </p><p> The Energy Aware Sink Relocation (EASR) is a method that prolongs the life of sensors by moving the sink to various locations in the network. By not keeping the sink at any specific location for too long, EASR improves the lifetime of sensors. This project presents an application of EASR to multi-sink networks. Simulation results show that the proposed method extends battery life of the network nodes.</p>

CubeSats have become an attractive platform for university-based spacecraft designs because they are cheaper and quicker to launch than full-scale satellites. One way of keeping costs for CubeSats low is using commercial off-the-shelf parts (COTS) instead of using space-qualified parts. Space-qualified parts are often costly, larger, and consume more power than their commercial counterparts prohibiting their use within a CubeSat. Given typical power budgets, monetary budgets, and timelines for CubeSat missions, conventional radiation hardness assurance, like the use of hardened parts and radiation testing campaigns of COTS parts, is not possible, requiring a system-level approach to radiation effects mitigation. In this thesis an assurance case for the radiation reliability of a CubeSat experiment is expressed using Goal Structuring Notation (GSN), a graphical argument standard. The case specifically looks at three main mitigation strategies for the radiation environment: total ionizing dose (TID) screening of parts, detection and recovery from single-event latch-ups (SEL) and single-event functional interrupts (SEFI). The graphical assurance case presented makes a qualitative argument for the radiation reliability of the CubeSat experiment using part and system-level mitigation strategies and is supported by functional and system models of the system.

<p>A novel hybrid regulator topology is proposed to alleviate the weaknesses of existing hybrid topologies. Contrary to the dominant existing practice, a switched-capacitor converter and a resistorless LDO operate in a parallel fashion to supply current and regulate the output voltage. The proposed topology targets a fully integrated regulator without using any inductors and resistors. The primary emphasis is on maximizing power efficiency while maintaining sufficient regulation capability (with ripple voltage less than 10% of the output voltage) and power density. The first implementation of the proposed topology operates in a single frequency mode. Simulation results in 45 nm technology demonstrate a power efficiency of approximately 85% at 100 mA load current with an input and output voltage of, respectively, 1.15 V and 0.5 V. The worst case transient response time is under 20ns when the load current varies from 65 mA to 130 mA. The worst case ripple is 22 mV while achieving a power density of 0.5 W/mm². This single-frequency hybrid voltage regulator is useful (due to its fast and continuous response and high power efficiency) when the output load current is relatively constant at a certain nominal value. However, the performance is degraded when the load current varies significantly beyond the nominal current since the current provided by switched-capacitor converter is constant. The second implementation of the proposed hybrid regulator topology partially alleviates this issue by employing two different frequencies depending on the load current. This design is also implemented in 45 nm technology. It is demonstrated that the power efficiency is maintained within 60% to 80% even though the load current varies by more than 100 mA. The power density remains the same (0.5 W/mm²). The simulation results of the proposed topology are highly competitive with recent work on integrated voltage regulators. </p>

<p> For an engineer, it is always a difficult task to deploy a distributed wireless sensor network for buildings, without initial planning of the infrastructure of the network. A robust network is one that provides entire connectivity without compromising the signal strength. Another important parameter to be considered is the cost of the network, which can be reduced by deploying the most optimized and resilient network. With this project, we have designed an interactive design tool using Matlab that can help an engineer to plan and place the router nodes before actual deployment. The reference methods are based on Dijkstra&rsquo;s algorithm, line based algorithm and clustering algorithm for placing of routers. In this project, we have used best from all the algorithms to present a novel approach for the placement of routers. This algorithm provides improved results than the reference methods and thus further reduces the cost of the network.</p>

<p> The use of hand gesture recognition has been steadily growing in various human-computer interaction applications. Under realistic operating conditions, it has been shown that hand gesture recognition systems exhibit recognition rate limitations when using a single sensor. Two dual-sensor approaches have thus been developed in this dissertation in order to improve the performance of hand gesture recognition under realistic operating conditions. The first approach involves the use of image pairs from a stereo camera setup by merging the image information from the left and right camera, while the second approach involves the use of a Kinect depth camera and an inertial sensor by fusing differing modality data within the framework of a hidden Markov model. The emphasis of this dissertation has been on system building and practical deployment. More specifically, the major contributions of the dissertation are: (a) improvement of hand gestures recognition rates when using a pair of images from a stereo camera compared to when using a single image by fusing the information from the left and right images in a complementary manner, and (b) improvement of hand gestures recognition rates when using a dual-modality sensor setup consisting of a Kinect depth camera and an inertial body sensor compared to the situations when each sensor is used individually on its own. Experimental results obtained indicate that the developed approaches generate higher recognition rates in different backgrounds and lighting conditions compared to the situations when an individual sensor is used. Both approaches are designed such that the entire recognition system runs in real-time on PC platform.</p>

Present trends of increasing health care costs, demand novel methods and tools for a transformation from a reactive and hospital-driven to a proactive, patient-centered and enabling healthcare. This work presents a modular wireless healthcare platform, that can be customized to meet different clinical and patient needs. It offers multiple sensing modalities to acquire a variety of physiological signals including bio-potentials, thoracic impedance, activity and posture, blood pressure, pulse wave form and blood oxygen saturation. A customized firmware allows for real-time digital signal processing to extract features, immediate alarm, feedback, and/or interface to therapeutic devices and procedures. The integration of our platform into mobile device technologies provides control and visualization of patient health data during treatment. Thus, patients can become actively engaged in their health and take responsibility leading to a potentially higher adherence to the treatment plan and early diagnosis. Real-time monitoring and immediate data transfer to a secured cloud based database provides decision support for physicians and caregivers and enables data mining to identify early markers for timely intervention in order to reduce costly hospital stays or re-admissions.

The increasing demand for local high-frequency operations on microprocessor and data-communication chips has led to the need for phase-locked loops to generate on-chip high-frequency clocks controlled by a much lower-frequency externally-provided system reference clocks. A high-frequency integrated CMOS phase-locked loop, which is independent of temperature and silicon processing variations, has been designed and tested. The system-level design was based on both frequency linear analysis and transient time-domain analysis performed using MTIME simulations. The design in this work integrates a phase-frequency detector, a symmetric charge-pump, an external low-pass RC loop filter, a digital-load-controlled voltage-controlled oscillator (DLCVCO), a programmable feedback-divider, a frequency-range detector (FRD), a circuit which initializes the loop filter node to VDD, a digital-load-activation cell, and associated circuitry on a portion of one die. The DLCVCO was implemented by a ring of three inverters; frequency was controlled by digitally programming the capacitive loads connected to its inner nodes. The FRD was designed to sense the temperature and silicon process conditions of the PLL system, and control the number of capacitive loads activated to the inner nodes of the DLCVCO. A 0.8 μm CMOS process was used to implement this PLL system design. Tests demonstrated that this PLL generated frequencies in excess of 200MHz, locked onto a 2MHz reference clock, and achieved a tuning range of 12MHz to 212MHz independent of silicon process variations and temperature conditions.

Suicide is a major health problem in the US, and has become an important topic of study. Recently, psychiatrists have reported hearing a particular sound or tonality in the voices of subjects that are at high risk of attempting suicide. This has lead to research to discriminate between depression and this high risk state based on the acoustic properties of the subject's voice, and has lead to some very promising results. Many of the features that have been used for this task are based on the power spectrum of the voice; however, it is not clear whether these features have captured the particular tonality that the psychiatrists have reported. The whole work attempts to address this question through analysis of speech data by calculating the harmonics, amplitudes, and other discriminating features from 6 depressed and 6 high risk subjects.