This dissertation addresses timing and synchronization methodologies that are critical to the design, analysis and optimization of high-performance, integrated digital VLSI systems. As process sizes shrink and design complexities increase, achieving timing closure for digital VLSI circuits becomes a significant bottleneck in the integrated circuit design flow. Circuit designers are motivated to investigate and employ alternative methods to satisfy the timing and physical design performance targets. Such novel methods for the timing and synchronization of complex circuitry are developed in this dissertation and analyzed for performance and applicability. Mainstream integrated circuit design flow is normally tuned for zero clock skew, edge-triggered circuit design. Non-zero clock skew or multi-phase clock synchronization is seldom used because the lack of design automation tools increases the length and cost of the design cycle. For similar reasons, level-sensitive registers have not become an industry standard despite their superior size, speed and power consumption characteristics compared to conventional edge-triggered flip-flops. In this dissertation, novel design and analysis techniques that fully automate the design and analysis of non-zero clock skew circuits are presented. Clock skew scheduling of both edge-triggered and level-sensitive circuits are investigated in order to exploit maximum circuit performances. The effects of multi-phase clocking on non-zero clock skew, level-sensitive circuits are investigated leading to advanced synchronization methodologies. Improvements in the scalability of the computational timing analysis process with clock skew scheduling are explored through partitioning and parallelization. The integration of the proposed design and analysis methods to the physical design flow of integrated circuits synchronized with a next-generation clocking technology-resonant rotary clocking technology-is also presented. Based on the design and analysis methods presented in this dissertation, a computer-aided design tool for the design of rotary clock synchronized integrated circuits is developed.

Application-driven processor designs are becoming increasingly feasible. Today, advances in field-programmable gate array (FPGA) technology are opening the doors to fast and highly-feasible hardware/software co-designed architectures. Over 100,000 FPGA logic array blocks and nearly 100 ASIC multiply-accumulate cores combine with extensible CPU cores to foster the design of configurable, application-driven hybrid processors. This thesis proposes a hardware/software co-designed architecture targeted to an FPGA. The architecture is a very-long instruction-word (VLIW) processor coupled with super-complex instruction set (SuperCISC) hardware co-processors. Results of the VLIW/SuperCISC show performance speedups over a single-issue processor of 9x to 332x, and entire application speedups from 4x to 127x. Contributions of this research include a 4-way VLIW designed from the ground up, a zero-overhead implementation of a hardware/software interface, evaluation of the scalability of shared data stores, examples of application-specific hardware accelerants, a SystemC simulator, and an evaluation of shared memory configurations.

Real time gas sensing is paramount to numerous applications in industry as well as in the consumer sector. Many gas sensing applications such as fossil energy production require low-cost, multi-species sensors that are able to operate in high-temperature, high-pollution environments under the presence of strong electromagnetic fields. Optical remote gas sensing using tunable lasers is regarded as the best sensing technology for hostile environments. However, optical technology often suffers from high component and operational costs. In this thesis, a tunable external-cavity fiber Bragg grating (FBG) diode laser was developed for spectroscopic chemical sensing. Although FBG lasers have been reported upon, previous works have focused primarily on telecommunications applications. This thesis reports the first application, to our best knowledge, of an FBG laser in chemical sensing. This fiber Bragg grating laser was comprised of an InGaAs/InP ridge-waveguide laser diode coupled to a length of SM-28 fiber bearing an FBG. The FBG is stretched via a piezo-electric actuator to allow rapid fine tuning of the output wavelength of the laser. This tunable external-cavity semiconductor laser was demonstrated with over 10 nm of tuning range. The measured spectral width of the laser was instrument-limited at less than 50 pm over the entire tuning range. The application of such low-cost tunable FBG lasers to spectroscopic chemical sensing was demonstrated in acetylene (C2H2) gas with a wavelength modulation spectroscopy technique. Both static and wavelength modulation absorption spectra of acetylene gas were observed by the tunable laser in acetylene partial pressures from 0.1 mbar to 100 mbar; the lowest detectable pressure being limited by the ultimate vacuum pressure and length of our gas cell. In terms of other optical gas sensing devices such as Distributed FeedBack lasers, FBG lasers offer much lower manufacturing costs and better temperature stability (13pm/ºK) over DFB lasers (>100 pm/ºK). The low manufacturing cost, good temperature stability, wide tuning range, and high output power make FBG lasers excellent candidates for the application of chemical sensing in the near IR band.

The growing complexity of Field Programmable Gate Arrays (FPGA's) is leading to architectures with high input cardinality look-up tables (LUT's). This thesis describes a methodology for area-minimizing technology mapping for combinational logic, specifically designed for such FPGA architectures. This methodology, called LURU, leverages the parallel search capabilities of Content-Addressable Memories (CAM's) to outperform traditional mapping algorithms in both execution time and quality of results. The LURU algorithm is fundamentally different from other techniques for technology mapping in that LURU uses textual string representations of circuit topology in order to efficiently store and search for circuit patterns in a CAM. A circuit is mapped to the target LUT technology using both exact and inexact string matching techniques. Common subcircuit expressions (CSE's) are also identified and used for architectural optimization---a small set of CSE's is shown to effectively cover an average of 96% of the test circuits. LURU was tested with the ISCAS'85 suite of combinational benchmark circuits and compared with the mapping algorithms FlowMap and CutMap. The area reduction shown by LURU is, on average, 20% better compared to FlowMap and CutMap. The asymptotic runtime complexity of LURU is shown to be better than that of both FlowMap and CutMap.

The field of nanophotonics has emerged as a promising platform for applications ranging from communications and computing, to sensing, solar energy harvesting, biomedicine, and beyond. Advancing these technologies requires developing and implementing new material systems, designs, and fabrication strategies. This dissertation focuses on two classes of nanomaterials with attractive optical characteristics: (1) porous nanomaterials and (2) phase change nanomaterials. Direct imprinting of porous subtrates (DIPS) is first introduced and demonstrated for the low-cost fabrication of micro- and nano-structures in porous media, including plasmonic or diffraction based sensors and porous microparticles relevant to drug delivery and imaging. DIPS is further demonstrated for 3D surface patterning and morphological control over local material properties. Second, the phase change nanomaterial vanadium dioxide (VO2) is integrated with silicon photonic components and a new ultra-compact platform for constructing active optical devices is demonstrated. With the hybrid Si-VO2 platform, record values of optically induced phase modulation and absorption modulation are achieved. The slotted photonic crystal nanobeam is also introduced and a low-mode volume nanocavity is demonstrated as an ultra-compact device for enhancing light-matter interactions, thus promoting further improvements to device footprint, sensitivity, and efficiency.

Cyber-physical systems, such as automotive vehicles, are very challenging to design because of the tight interactions between physical dynamics, computational dynamics and communication networks. In addition, the evaluation of these systems in the early design stages is very crucial and challenging. Model-based design approaches have been applied in order to manage the complexities due to interactions. In this thesis, a study to demonstrate the systematic design, analysis and evaluation of an integrated automotive control system is presented. In detail, following the model based design method, a vehicle lane keeping controller is designed and implemented on a time triggered platform which is running on real time Linux. Then the control design is verified by both of Simulink simulation and hardware-in-the-loop simulation. After that, a vehicle integrated control system is built by the integration of two independently designed controllers, lane keeping controller (LKC) and adaptive cruise controller (ACC). During the integration, the interaction and conflict between different controllers are analyzed then a supervisor control is designed to coordinate LKC and ACC under the situation when there is a conflict. Simulink simulations are performed to proof the necessity of supervisor controller. Finally, the integrated system is deployed on a hardware-in-the-loop simulator for evaluation under realistic scenarios. By the HIL simulation result, the control effects introduced by the real time platform and communication network are also observed. The efficiency of the approach is also present experimental results that demonstrate.

Avionics systems play a critical role in many aspects of aircraft flight control. As the complexity of these systems increase, the chances of in-flight malfunctions are also likely to increase. This drives the need for Integrated Vehicle Health Management (IVHM) technologies for flight-critical avionics. Studying and analyzing the performance degradation of embedded electronics in the aircraft domain will help to increase aircraft reliability, assure in-flight performance, and reduce maintenance costs. Further, an understanding of how components degrade as well as the capability to anticipate failures and predict the remaining useful life (RUL) can provide a framework for condition-based maintenance. To support a condition-based maintenance and a safety-critical analysis framework, this thesis conducts a detailed study of the degradation mechanisms of electrolytic capacitors, an important component of most electronic systems. Electrolytic capacitors are known to have lower reliability than other electronic components that are used in power supplies of avionics equipment and electrical drivers of electro-mechanical actuators of control surfaces. Therefore, condition-based health assessment that leverages the knowledge of the device physics to model the degradation process can provide a generalized approach to predict remaining useful life as a function of current state of health and anticipated future operational and environmental conditions. We adopt a combined model and data-driven (experimental studies) approach to develop physics-based degradation modeling schemes for electrolytic capacitors. This approach provides a framework for tracking degradation and developing dynamic models to estimate the RUL of capacitors. The prognostics and RUL methodologies are based on a Bayesian tracking framework using the Kalman filter and Unscented Kalman filter approaches. The thesis makes contributions to physics-based modeling and a model-based prognostics methodology for electrolytic capacitors. Results discuss prognostics performance metrics like the median relative accuracy and the á-ë (alpha-lambda) accuracy. We have also demonstrated the derived physics-based degradation model is general, and applied to both accelerated and nominal degradation phenomena. Our overall results are accurate and robust, and, therefore, they can form the basis for condition-based maintenance and performance-based evaluation of complex systems.

Single-event mechanisms in InAlSb/InAs/AlGaSb high electron mobility transistors (HEMTs) are identified and investigated. Single-event transients are characterized using broadbeam and microbeam experiments along with 2-D technology computer-aided design (TCAD) modeling. The experiments show that single-event transients can be generated not only in the channel region but also across the drain-source alloy and buffer interface. The prevalence of strong single-event transient sensitivity to gate bias is demonstrated through broadbeam experiments, where the integrated charge peaks at threshold bias and drops off at both depletion and accumulation biases. A type-II band alignment in the InAlSb/InAs/AlGaSb HEMT modulating charge transport and electric field in the channel is shown to be responsible for the observed single-event transient sensitivity to gate bias. The effects of processing-induced device threshold voltage variations on the corresponding single-event response are studied through 2-D TCAD modeling.

Total ionizing dose (TID) effect is a kind of radiation effects. Its related with the charge build up in the insulator caused by the radiation. This radiation induced charge build up will pose reliability issue and is a big concern. Sometimes real time knowledge of the total dose level is necessary. Traditional methods measure the radiation induced threshold voltage shift, which is directly related with the total dose level. Such methods include the discrete PMOS RadFET and delay locked loop circuit. However they are either hard to integrate with the scaling of technology or requires complicated circuit and curve fitting. Moreover, the detection range is very limited and the linearity is poor. In contrast, the leakage current measurement circuit is easy to build and have a wide detection range as well as the good linearity. So its taken here. After the integration of all the components, a key question that needs to answer is whether the fully integrated TID monitor will work or not, especially when both the sensing device and measurement circuit are exposed to radiation. This thesis presents a validation of the argument that in a certain range, it would work.

Cyber-Physical Systems pair discrete-event computational components with physical components--like electronic circuits--which are governed by continuous-time dynamics. If we are able to simultaneously model the computational and physical aspects of a system, then we could drastically shorten timelines for such systems by being able to simulate, evaluate, and formally verify integrated system behavior all prior to the costly phase of system deployment. Model simulations allow designers to test safety critical use scenarios, and can form a basis for system parameterization. In this work, we present the Signal Flow Domain Specific Modeling Language (DSML) which serves as a free and open language for describing synchronous control logic within the Embedded Systems Modeling Language Framework (ESMoL) and the Cyber-Physical Systems Modeling Language (CyPhyML). Signal Flow is adept at modeling software processes, and its functional blocks are math functions which reference underlying C-code snippets. Furthermore, Signal Flow models can synthesize deployable C-code, for use within the target hardware platform. We describe the use of Signal Flow within CyPhyML for integrating the computational and physical components of a bidirectional DC/DC converter intended for use in a hybrid vehicle. The full system was modeled in CyPhyML with the vehicle controller employing the Signal Flow DSML. All possible converter mode transitions are composed and simulated as testbenches, and their results illustrate expected system behavior with the controller working seamlessly with the physical circuit model.