by Chin Yu-Tung. / Thesis (M.Phil)--Chinese University of Hong Kong, 1981. / Bibliography: leaf 32.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

A delay discounting survey was provided to 30 participants to assess hypothetical choices. Each question provided choices between using a complementary plastic bag and harming an ocean animal or purchasing a reusable bag and not harming an ocean animal. Participants were randomly assigned to complete a control or values-based activity. The values-based activity utilized Acceptance and Commitment Therapy to assist in identifying participants’ values and committed actions, whereas the control activity included a word association game. Discounting scores were calculated across delay discounting surveys conducted pre- and post-activity completion. The purpose of the study was to assess relationships between completion of activities (values-based or control) and discounting scores on items pertaining to environmental sustainability. Implications, limitations, and future directions are provided and discussed

Standard-Cell-library-based design ow is widely followed in the Application Specific Integrated Circuit(ASIC) industry. Most of the realistic cell libraries are geometrically spaced introducing significant sparseness in the library. This is because uniformly spaced gate sizes would result in a large number of gate sizes and maintaining the huge volume of data for this number of gate sizes is difficult. This thesis aims to propose a practical approach to implement integer gate sizes. A parameterized cell (p-cell) approach to the generation of layouts of standard gates is presented. The use of constant delay model for gate delay estimation is proposed which eliminates the need for maintaining huge volumes of delay tables in the standard cell library. This approach has tremendous potential since it greatly simplifies the standard-cell-based design methodology and can give significant power and area savings.Power and area savings of up to 28% are possible using this approach.

Networks, and associative properties, prevalent in natural and artificial systems have been investigated extensively. A common method for network analysis is based on graph theory because graphs naturally represent the relationship between objects in a network. In this context, three classes of networks are frequently investigated: random, scale-free, and small-world network. The three classes of networks have been studied extensively, to find properties and to analyze the structure of each network type using various measurements. Despite that all real networks have time delays, researchers relying on graph theory commonly disregarded delay or considered them only as being homogeneous. Delay cannot be ignored because delay has a critical role in many types of networks, such as the internet, business networks, and biological networks. The role and effect of delay, however, are still not clearly understood in the context of graph-based analysis. Furthermore, graph-based analysis of networks containing delay has not been attempted so far. In this thesis, I compared multiple network structures with delay in a graph context. I incorporated delay information into the network topology by a simple technique called temporal augmentation. Also, I investigated the effect of varying the delay distribution in these different network classes with added delay. In this thesis, several experiments were conducted based on two network construction methods (naive, and modified conventional method) and three types of delay distributions (peaked, uniform, and unimodal), with different network parameters. From the experiments, I found that the effect of the number of hubs in scale-free network was negligible, while the role of neighborhood size in small-world networks was significant. Also, neighborhood size affect smallworldness of networks. Effect of delay was expressed differently based on different patterns of delay distribution and network structures. Networks with uniformly randomly distributed delay had the best robustness in dealing with delay. Unimodal cases had larger increases in shortest path sum than uniform case. Peaked cases showed the worst increase in shortest path sum. Also, sparse networks with high smallworldness was less affected by delay while dense networks with high smallworldness more affected by delay. These results extended understanding of the relationship between network structures and delay.

Elastography is a non-invasive medical imaging modality that is used as a diagnostic tool for the early detection of several pathological changes in soft tissues. Elastography techniques provide the local strain distributions experienced by soft tissues due to compression. The resulting strain images are called “elastograms”. In elastography, the local tissue strains are usually estimated as the gradient of local tissue displacement. The local tissue displacements are estimated from the time delays between gated pre- and post-compression echo signals. The quality of the resulting elastograms is highly dependent on the accuracy of these local displacement estimates. While several time delay estimation (TDE) techniques have been proposed for elastography applications, there is a lack of systematic study that statistically compares the performance of these techniques. This information could prove to be of great importance to improve currently employed elastographic clinical methods. This study investigates the performance of selected time delay estimators for elastography applications. Time delay estimators based on Generalized Cross Correlation (GCC), Sum of Squared Differences (SSD) and Sum of Absolute Differences (SAD) are proposed and implemented. Within the class of GCC algorithms, we further consider: an FFT-based cross correlation algorithm (GCC-FFT), a hybrid time-domain and frequency domain cross correlation algorithm with prior estimates (GCC-PE) and an algorithm based on the use of fractional Fourier transform to compute the cross correlation (GCC -FRFT) . Image quality factors of the elastograms obtained using the different TDE techniques are analyzed and the results are compared using standard statistical tools. The results of this research suggests that correlation based techniques outperform SSD and SAD techniques in terms of SNRe, CNRe, dynamic range and robustness. The sensitivity of GCC-FFT and SSD were statistically similar and statistically higher than those of all other methods. Within the class of GCC methods, there is no statistically significant difference between SNRe of GCC-FFT, GCC-PE and GCC –FRFT for most of the strain values considered in this study. However, in terms of CNRe, GCC-FFT and GCC-FRFT were significantly better than other TDE algorithms. Based on these results, it is concluded that correlation-based algorithms are the most effective in obtaining high quality elastograms.

The focus of the present thesis is the circuit-level implementation of an excess loop delay compensation scheme which optimizes excess loop delay in Analog-to-Digital Converter(ADC) by using a programmable delay block and synchronizes the signal passing through Dynamic Element Matching block, used to mitigate mismatch effects of multi-bit Digital-to-Analog Converter(DAC). The proposed delay block has tuning range of T/10 to T/2 seconds, with a step size of T/30 seconds, where T is the time period (1.25 nanoseconds) of sampling signal (800 MHz) in high IF (200 MHz) Bandpass [sigma delta] ADC. The implementation details of the element rotation scheme used to calibrate the multi-bit DAC static error mismatch are also presented. Also presented is the design of high frequency highly linear Operational Transconductance Amplifier(OTA) targeted for continuous-time filters in a high resolution High Intermediate Frequency (200 MHz) Bandpass [sigma delta] ADC for Software Radio applications. Proposed OTA uses super source follower input stage to enhance its voltage-to-current conversion linearity. The design has been simulated using TSMC 0.18 μm CMOS process. The OTA has small signal transconductance of 0.9 mA/V, IM3 below -79 dB (for 0.3 Vpp input), Signal-to-Noise Ratio of 82 dB and power consumption of 6.8 mW, when tested in unity gain configuration.

For continuous-time descriptor systems with all system matrices incorporated with norm-bounded uncertainties, this thesis addresses robust admissibility and robust H¡Û analysis and the related state feedback design. The results are further extended to systems with time-varying state delay within a known interval. The former part of the thesis extends the current research of considering uncertainty only at the state derivative matrix to the case uncertainty being assumed at all system matrices. While the latter part of the thesis extends the current research in two folds: the state derivative matrix is allowed to be uncertain and the delay is allowed to be time-varying. Since all the results are derived in the LMI-based framework, examples with efficient numerical verifications are included to illustrate the derived results.

Title from PDF of title page (University of Missouri--Columbia, viewed on Feb 16, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Dissertation advisor: Dr. Roger Fales. Vita. Includes bibliographical references.

published_or_final_version / Mechanical Engineering / Doctoral / Doctor of Philosophy