In most techniques to improve performance for loops or nested loops, they are often to do pipelined scheduling according to know loop execution times at compiler time. But it is hardly to pipeline the execution of loop whose execution length is unknown before loop execution at compiler time. In this thesis, a Common-Case based approach is proposed to improve the performance of loops with variable execution length. Besides, we use the modulo schedule to achieve the goal under resource constraint and without violating data dependence. The Common-Case approach not only reduces the execution time efficiently, but also reduces the power consumption largely due to the reduction of execution time. Through the searching for good Common-Case, we can surely supply a better solution to the loops whose execution length is unknown before loop execution at compiler time. Moreover, since the loop is divided into Common-Case and exception parts, we can further reduce power consumption by using Clock-Gating and Finite State Machine decomposition techniques. Finally, experiments on three real examples (Morris-Pratt Algorithm, Insertion Sort, Running Length Encoding) are used to demonstrate that our flow is correct and can achieve the goal of performance and energy optimizations.

The objective of this thesis is to solve the trajectory tracking control problems of the mobile manipulators in two stages. In the first stage, a desired velocity input function for a steering system is designed by using Lyapunov stability theorem so that the posture of the mobile manipulator can track the reference trajectory. Further analysis shows that the vehicle of the mobile manipulator will achieve better result of trajectory tracking than the existent methods if the reference trajectory of the vehicle is not assigned to be static condition. In the second stage, the torque controller of the dynamic equations of the mobile manipulator with perturbations and input uncertainty is designed by adaptive variable structure control (AVSC) methodology, so that the actual velocity can track the desired velocity input function designed in the first stage. In addition, this controller with an adaptive mechanism embedded is capable of suppressing the perturbations with unknown upper bound except that from the input channel, and achieve asymptotical stability under certain mild conditions. Finally, an example of a two-link wheeled mobile manipulator is presented to demonstrate the feasibility of the proposed control schemes.

The first topic of this thesis is to carry out a multi-symbol codec (encoder-decoder) design for interfacing variable-length and fixed-length data conversion of H.263. The poor memory efficient of the variable-length can be avoided while its advantages can be reserved. The proposed codec converts variable-length symbols to fixed-length packets which can be decoded parallelly. The basic idea is to encode extra symbols in the redundant bits of the fixed-length packets. This encoding scheme relaxes the intrinsic poor compression rate of the prior fixed-length data codec. The second topic is a synthesizable Verilog code generator for the mentioned multi-symbol codec. According to different requirements and constraints of encoding bit rate, the generator can provide several different kinds of encoding modes by selecting proper parameters. Each codec generated by the generator is synthesizable by thorough simulations.

A simple technique of designing a robust discrete-time variable structure output tracking controller for a class of perturbed MIMO linear and nonlinear systems is proposed in this thesis. For linear systems, a model reference scheme is employed. Both an adaptive mechanism and a perturbation estimation process are embedded in the proposed control scheme. The information of the upper bound of the perturbation estimation error is not required due to the usage of adaptive mechanism. It is shown that the dynamics of the controlled systems will be driven into the vicinity of the designed switching surface, therefore the tracking error will be constrained in a small bounded region. Furthermore, the stability of the overall controlled system is guaranteed, and one can increase the tracking accuracy by adjusting the controller's parameters or by employing the perturbation estimation process.

This thesis presents a 2.4GHz image-reject downconverter fabricated in TSMC 0.25 1P5M CMOS process. The integrated active filter can not only filter out the image signal, but also reduce noise figure degraded by parasitic capacitance in the circuit. The differential LC oscillator fabricated in TSMC 0.35 1P4M CMOS process has properties of low phase noise and wide frequency turning range. Finally, a variable gain amplifier implemented in GCS GaAs HBT process was designed using signal summing architecture. The architecture is advantageous to reducing noise, distortion and increasing operating frequency. This thesis has studied what cause the difference between measurement and simulation for better performance in the future design.

Based on the Lyapunov stability theorem, two different variable structure controllers are proposed in this thesis for two different classes of multi-variable descriptor systems subject to matched nonlinear perturbations. The integral variable structure controller is proposed first for solving the stabilization problems, and model reference variable structure controller is the second for solving the state tracking problems. Both proposed control schemes can guarantee the trajectories of the controlled systems to lie in the sliding surface from initial time, so that the properties of regularity, impulse free, and stability can be obtained. Two numerical examples are given for demonstrating the feasibility of the proposed control schemes.

To detect dependence among variables is an essential task in many scientific investigations. In this study we propose a new measure of association, the coefficient of intrinsic dependence (CID), which takes value in [0,1] and faithfully reflects the full range of dependence for two random variables. The CID is free of distributional and functional assumptions. It can be easily implemented and extended to multivariate situations. Traditionally, the correlation coefficient is the preferred measure of association. However, it's effectiveness is considerably compromised when the random variables are not normally distributed. Besides, the interpretation of the correlation coefficient is difficult when the data are categorical. By contrast, the CID is free of these problems. In our simulation studies, we find that the ability of the CID in differentiating different levels of dependence remains robust across different data types (categorical or continuous) and model features (linear or curvilinear). Also, the CID is particularly effective when the dependence is strong, making it a powerful tool for variable selection. As an illustration, the CID is applied to variable selection in two aspects: classification and prediction. The analysis of actual data from a study of breast cancer gene expression is included. For the classification problem, we identify a pair of genes that best classify a patient's prognosis signature, and for the prediction problem, we identify a pair of genes that best relates to the expression of a specific gene.

The quasi-steady, spherically symmetric combustion of multicomponent isolated fuel droplets has been modeled using modified Shvab-Zeldovich variable mechanism. Newly developed modified Shvab-Zeldovich equations have been used to describe the gas phase reactions. Vapor-liquid equilibrium model has been applied to describe the phase change at the droplet surface. Constant gas phase specific heats are assumed. The liquid phase is assumed to be of uniform composition and temperature. Radiative heat transfer between the droplet and surroundings is neglected. The results of evaporation of gasoline with discrete composition of hydrocarbons have been presented. The evaporation rates seem to follow the pattern of volatility differentials. The evaporation rate constant was obtained as 0.344mm2/sec which compared well with the unsteady results of Reitz et al. The total evaporation time of the droplet at an ambience of 1000K was estimated to be around 0.63 seconds. Next, the results of evaporation of representative diesel fuels have been compared with previously reported experimental data. The previous experiments showed sufficient liquid phase diffusional resistance in the droplet. Numerical results are consistent with the qualitative behavior of the experiments. The quantitative deviation during the vaporization process can be attributed to the diffusion time inside the droplet which is unaccounted for in the model. Transient evaporation results have also been presented for the representative diesel droplets. The droplet temperature profile indicates that the droplet temperature does not reach an instantaneous steady state as in the case of single-component evaporation. To perform similar combustion calculations for multicomponent fuel droplets, no simple model existed prior to this work. Accordingly, a new simplified approximate mechanism for multicomponent combustion of fuel droplets has been developed and validated against several independent data sets. The new mechanism is simple enough to be used for computational studies of multicomponent droplets. The new modified Shvab-Zeldovich mechanism for multicomponent droplet combustion has been used to model the combustion characteristics of a binary alcohol-alkane droplet and validated against experimental data. Burn rate for the binary droplet of octanol-undecane was estimated to be 1.17mm2/sec in good concurrence with the experimental value of 0.952mm2/sec obtained by Law and Law. The model has then been used to evaluate the combustion characteristics of diesel fuels assuming only gas phase reactions. Flame sheet approximation has been invoked in the formulation of the model.

Based on the Lyapunov stability theorem, a methodology of designing robust discrete-time model reference variable structure state tracking controller is proposed in this thesis for a class of multi-input multi-output (MIMO) discrete-time systems. This variable structure controller is composed of three types of controllers. The first one is the feedback control law, which can eliminate the nominal term in the derivative of a Lyapunov function. The second one is the switching control law, which can determine the decreasing rate of the Lyapunov function. The third one is the adaptive control law, which is used to overcome the perturbations. The resultant robust variable structure controllers are capable of driving all the trajectories of tracking errors toward a small bounded region. The information of upper bound of the perturbation, which is not a constant and is dependent on the norm of state variable, is not required beforehand due to some adaptive mechanisms are embedded in the proposed control scheme, and the stability of the overall controlled system is guaranteed. A numerical example and a practical example are given to demonstrate the feasibility of the proposed control scheme.

We consider the constrained convex minimization problem min x2C f(x) we will present gradient projection method which generates a sequence fxkg according to the formula xk+1 = PC(xk