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Constrained controllability in delay system.January 1981 (has links)
by Chin Yu-Tung. / Thesis (M.Phil)--Chinese University of Hong Kong, 1981. / Bibliography: leaf 32.
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Performance evaluation of techniques for time delay estimationScarbrough, Kent N January 2010 (has links)
Typescript (photocopy). / Digitized by Kansas Correctional Industries
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The roles of values in discounting the use of plastic bags and harming ocean animalsHolecek, Megan Elizabeth 01 August 2019 (has links)
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
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A p-cell approach to integer gate sizingDoddannagari, Uday 15 May 2009 (has links)
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.
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Effect of varying the delay distribution in different classes of networks: random, scale-free, and small-worldJang, Bum Soon 15 May 2009 (has links)
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.
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Comparison of the Performance of Different Time Delay Estimation Techniques for Ultrasound ElastographySambasubramanian, Srinath 2010 August 1900 (has links)
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.
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Design techniques for high intermediate frequency bandpass (sigma/delta) modulator.Kode, Praveena 10 October 2008 (has links)
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.
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Delay-Dependent Robust H¡Û Analysis and Design for Uncertain Continuous Time-Delay Descriptor Systems with Delay Varying in a RangeHo, Jen-Dar 28 August 2009 (has links)
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.
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Developing and automating time delay system stability analysis of dynamic systems using the Matrix Lambert W (MLW) function methodPietarila, Kristel M., Fales, Roger. January 2009 (has links)
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.
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Stability analysis and controller synthesis of continous-time linear time-delay systemsDu, Baozhu., 杜宝珠. January 2010 (has links)
published_or_final_version / Mechanical Engineering / Doctoral / Doctor of Philosophy
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