In recent years, more and more efforts have been put on creating robots that operate in domestic environments. A robotic simulation environment for testing, developing and deploying motion planning is extremely necessary for both research and real-world robotics applications. In this thesis, a newly released robotic real-time simulations software library called Open Robotics Automation Virtual Environment (OpenRAVE) has been used to simulate a robot playing the Tower of Hanoi using sensor feedback. The research demonstrates and evaluates the robotic simulator OpenRAVE with sensor feedback using the Tower of Hanoi puzzle as an example to develop test scenes and programs. The algorithm developed in this thesis can solve the puzzle with different initial disks positions so that multiple simulation test scenes could be created to thoroughly and comprehensively measure the performance of robot simulator. The manipulation planning algorithms of OpenRAVE have also been discussed. The physics engine of the simulator ODE provides a real-time robot simulation with gravity and friction force applied. Four the robotic simulation environment scenes have been built in OpenRAVE and the robot has successfully accomplished the Tower of Hanoi puzzle in different circumstances. All the simulation experiments prove that OpenRAVE is a powerful and easy-to-use robot simulator with strong reliability and suitability for this research.

Gallium Nitride (GaN)-based devices are used in space-based high power, high frequency applications due to high breakdown voltage and high carrier mobility and the large bandgap of GaN. The radiation effects and hot carrier degradation of AlGaN/GaN HEMTs are investigated in this work. Low frequency noise measurements are employed to help understand the nature of the defects that are responsible for the reliability and radiation response of GaN HEMT devices. The HEMT devices show excellent radiation hardness to 10-keV X-ray irradiation but 1.8 MeV proton irradiation results in a positive shift in the threshold voltage and reduction in current and transconductance. The temperature-dependent noise spectra show changes in defect distributions, with activation energy barriers of 0.2 eV, 0.6 eV and 0.9 eV. Density functional theory (DFT) calculations suggest that these energy levels are related to the dehydrogenation of ON-H defects. The noise spectra after hot carrier effects show similar features as those after proton exposure, strongly suggesting that dehydrogenation of ON DX centers takes place during the proton irradiation. The threshold voltage shift is negative after hot carrier stress, suggesting that other defects dominate the process that are out of the range of temperature-dependent noise measurement.

Network-on-chip (NoC) architectures with emerging interconnect technologies have been developed to meet the demand for high-performance computational systems while maintaining energy efficiency. The introduction of deflection routing and bufferless router architectures offers smaller area and lower power consumption for on-chip networks that connect cache to multicore processors. The design of the deflection-routing algorithm is the key for maintaining the performance of the network. This paper presents an investigation of the hardware implementation for a bufferless router. We determine the critical path to maximize the work done per stage for a pipelined architecture. Our design improves the deflection rate when compared to previous literature. We also improve the design based upon the physical implementation by balancing the delay through the pipeline stages. Our design was prototyped using a field-programmable gate array (FPGA) to construct a mesh topology to evaluate the performance. The average latency for flits is reduced by up to 16.2% versus a baseline design.

Bias-temperature-instabilities (BTIs) and total ionizing dose effects are investigated for 4H-SiC MOS devices. Low frequency noise measurements are employed to help understand the nature of the defects that affect the reliability and radiation response of SiC MOS devices. Threshold voltage shifts due to BTI correlate strongly with the additional ionization of deep dopants in SiC at elevated temperatures. The charge that leads to BTI lies in interface traps that are more than 0.6 eV below the SiC conduction band, nitrogen related defects, and O vacancies in the SiO2. Switching bias between irradiation and annealing can lead to significant enhancement of degradation in SiC MOS devices. The pair of positive/negative gate bias during irradiation/annealing on p-substrate capacitors is found to be worst-case for degradation. The 1/f noise in 4H-SiC MOSFETs is dominated by the interaction of channel carriers with slow interface traps at temperatures below 360 K and with border traps above 360 K. The interface traps related to 1/f noise are identified as carbon vacancy clusters and nitrogen dopant atoms at or near the SiC/SiO2 interface through first-principle calculations and TCAD simulations.

In a radiation environment analog circuits are particularly susceptible to radiation effects, due to stringent requirements on signal integrity and precision. This dissertation demonstrates system-level radiation-hardening-by-design (RHBD) techniques for analog circuits, with a focus on low-voltage designs to support portability across modern technology nodes. Radiation effects analyses and hardening schemes are presented for both continuous- and discrete-time circuits. A CMOS voltage reference is used as a case study for continuous-time circuits, in which the total dose response is dominated by mismatch effects. Experiments demonstrate how chopper stabilization improves the radiation response by mitigating these effects. A switched-capacitor (SC) sample/hold amplifier is used as a case study for discrete-time circuits, in which floating nodes are especially sensitive to single events (SEs). Quad-path hardening is experimentally demonstrated to mitigate SE-induced errors in SC circuits that use complementary switches. Each case study demonstrates system-level RHBD schemes that are applicable to a wide variety of continuous- and discrete-time analog/mixed-signal circuits.

In this work the impact of technology trends on alpha particle induced soft error rates in state-of-the-art commercial microprocessors has been investigated. At the device level, both critical charge and charge collection efficiency decreases as technologies move to the next generation. For the two technology nodes studied in this work, process improvements outpace the reduction of supply voltage and capacitance. At the circuit level, latch design has a profound impact on the SER contribution from the core logic part of the microprocessor. Elimination of floating nodes is the key to improving the SER susceptibility of the chip. At the system level, the contribution from the cache dominates the overall chip level SER. However, with ECC protection the SER contribution from the core logic is becoming more important to chip level SER. The SER frequency trend is determined by its circuit topology. SER contribution from the core logic decreases with clock frequency when transmission-gate latches are heavily used, and an opposite frequency trend is observed when differential sense amplifier latches are used.

In this dissertation, two decorrelation techniques are proposed for the application of lossless and lossy image compression. The basic concept of the proposed methods is based on interpolative subband decomposition. The interpolation filters used in the proposed schemes are adapted to satisfy the characteristic of image being decomposed. Furthermore, the interpolation filter parameters are optimally designed based on an l1 and l2 norm minimization to reduce statistical dependence between the detail subbands as much as possible. The first technique, the optimum scalar decomposition, simply decomposes image into subbands where one subband is retained and other subband is approximated by a scalar multiple of the retained subband. Contrarily, to improve the decorrelation performance, the other technique movivated by the linear decomposition transform employs a two-dimensional decorrelation structure to decorrelate the decomposed subbands. In this study, the decorrelation performance evaluations of the proposed decorrelation methods are examined and compared with those obtained from the linear decomposition transform and the S+P-transform. For lossless image compression, the comparative Huffman and SPIHT coding results (bits/pixel) obtained from the proposed schemes, the linear decomposition transform, and the S+P-transform are illustrated. In lossy image compression, however, not only the numerical results but also the perceptual image quality obtained with the proposed methods are compared to those employing the linear decomposition transform and the wavelet transform. For numerical results, the fidelity of reconstructed images are evaluated in terms of PSNR(dB), PNE1(%), and PNE2(%) criteria. The Fourier transforms phase and magnitude components of the reconstructed images are compared to the original image in term of SNR(dB). Moreover, the Sobel edge operator is employed to investigate edge preservation in the reconstructed images obtained by different tested methods compared to the original image.

Numerical process and device simulation tools are used in this work to analyze the physical mechanisms that contribute to catastrophic failure of power Schottky diodes exposed to an electron beam pulse. Simulations suggest that the diodes fail at the guard ring edge due to depletion region collapse that effectively shorts the guard ring to the substrate, leading to high current densities and thermal runaway. Numerical simulations are also used to examine techniques to increase survivability.

The role of communication among mobile robots remains one of the most important issues in multi-agent robotics system design. There are many research groups currently working on communication and cooperation among robots. Cooperation requires communication whenever ones actions depend critically on the knowledge that is accessible only from others. In the Intelligent Robotics Laboratory at Vanderbilt University, we are currently developing a method for robots to communicate and share knowledge with each other. We have developed the concept of the Peer Agent that will enable robots to exchange information between one another. The research experiment, described in this thesis, involved two mobile robots; Skeeter, a Pioneer 2-AT robot and Scooter, an ATRV-Jr robot. We will show that knowledge sharing through Peer Agents can lead to a more stable, robust and efficient cooperation between robots.

In robotics, we need robots which have the ability to understand what a human wants and can respond accordingly. On the other hand, robot should be able to provide information that is easy for a human to understand. Therefore, we developed the robot Self Agent to provide these abilities. The main purpose of the Self Agent is to be the center of the robot. It provides every basic need that a robot should have. For example, translating high-level command into basic commands so that a robot can understand and execute them; Self-monitoring of the robots performance; and having an intelligent action selection that will make good decisions. Since we needed to have a good decision mechanism, we created a new approach which consists of two algorithms. The first algorithm is Spreading Activation Network (SAN) that provides the basis for selecting appropriate behaviors (Action Selection) for completing a given task. To perform well, parameters of the Spreading Activation Network must be manually tuned. The second algorithm is the Reinforcement Learning (RL) technique that enables a robot to automatically learn multiple policies. This research will show we trained an ATRV-Jr robot, called Scooter to learn policies and automatically adapt to unexpected variables.