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The Longest Common Subsequence Problem with a Gapped ConstraintCheng, Kai-Yuan 12 September 2012 (has links)
This thesis considers a variant of the classical problem for finding the longest common subsequence (LCS) called longest common subsequence problem with a gapped constraint (LCSGC). Given two sequences A, B, and a constrained sequence C, which is accomplished with a corresponding gapped constraint for each symbol, whose lengths are m, n, and r, respectively, the LCSGC problem is to find an LCS of A and B, such that C is also a subsequence of this LCS and the gapped constraints corresponding to C are satisfied. In this thesis, two algorithms with time complexities O(m2n2r) and O(mnr ¡Ñ min(m, n)) are proposed based on the dynamic programming technique for solving the LCSGC problem.
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Evaluation of healing in asphalt binders using dynamic shear rheometer and molecular modeling techniquesBommavaram, Ramamohan Reddy 15 May 2009 (has links)
A self-healing material has the inherent ability to partially reverse damage such as crack
formation that might have occurred during its service. Significant evidence exists in the
literature to indicate that asphalt binder is a self-healing material. It is also well known
that healing has a substantial affect on the performance of asphalt mixtures and
consequently on the serviceable life of asphalt pavements. For example, shift factors from
laboratory experimental data to field observed data show that laboratory data underpredict
field observations. There is a need to understand the mechanisms that are
responsible for healing in asphalt binders as well as to develop test methods that can be
used to determine properties related to these mechanisms. This thesis presents details
and findings from a two-part study that addresses each one of these two aspects. In the
first part of this study, a test method based on the use of a Dynamic Shear Rheometer
(DSR) was developed to determine the parameters of characteristic healing function of
asphalt binders. In the second part of this study, Molecular Modeling (MM) techniques
were used to determine the interrelationship between molecular structure, surface free
energy, self diffusivity, and other healing properties of asphalt binders.The healing characteristic equation parameter (Ro) which represents the
instantaneous healing nature of the asphalt binders is analogous to surface energy in
terms of effect on healing in asphalt binders. Ro values for three asphalt binders AAM,
AAD and ABD are calculated and compared with the surface energy values available
from the literature. It was observed that the Ro values are proportional to surface energy
values. Surface energy values for five asphalt binders AAM, AAD, AAB, AAG and AAF
are calculated using MM method based on SHRP representative molecules. These values
were observed to be proportional to the surface energy values from literature. Bulk and
surface diffusion coefficients of asphalt molecules are calculated using MM method.
Parametric analysis was done to determine the effect of chemical structure of asphalt on
its diffusion properties. It was observed that the higher percentage of saturates in the
chemical structure results into higher diffusion coefficients.
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Dynamic fluorescence imaging with molecular agents for cancer detectionKwon, Sun Kuk 15 May 2009 (has links)
Non-invasive dynamic optical imaging of small animals requires the
development of a novel fluorescence imaging modality. Herein, fluorescence imaging is
demonstrated with sub-second camera integration times using agents specifically
targeted to disease markers, enabling rapid detection of cancerous regions. The
continuous-wave fluorescence imaging acquires data with an intensified or an electronmultiplying
charge-coupled device. The work presented in this dissertation (i) assessed
dose-dependent uptake using dynamic fluorescence imaging and pharmacokinetic (PK)
models, (ii) evaluated disease marker availability in two different xenograft tumors, (iii)
compared the impact of autofluorescence in fluorescence imaging of near-infrared (NIR)
vs. red light excitable fluorescent contrast agents, (iv) demonstrated dual-wavelength
fluorescence imaging of angiogenic vessels and lymphatics associated with a xenograft
tumor model, and (v) examined dynamic multi-wavelength, whole-body fluorescence
imaging with two different fluorescent contrast agents.
PK analysis showed that the uptake of Cy5.5-c(KRGDf) in xenograft tumor
regions linearly increased with doses of Cy5.5-c(KRGDf) up to 1.5 nmol/mouse. Above 1.5 nmol/mouse, the uptake did not increase with doses, suggesting receptor saturation.
Target to background ratio (TBR) and PK analysis for two different tumor cell lines
showed that while Kaposi’s sarcoma (KS1767) exhibited early and rapid uptake of
Cy5.5-c(KRGDf), human melanoma tumors (M21) had non-significant TBR differences
and early uptake rates similar to the contralateral normal tissue regions. The differences
may be due to different compartment location of the target.
A comparison of fluorescence imaging with NIR vs. red light excitable
fluorescent dyes demonstrates that NIR dyes are associated with less background signal,
enabling rapid tumor detection. In contrast, animals injected with red light excitable
fluorescent dyes showed high autofluorescence.
Dual-wavelength fluorescence images were acquired using a targeted 111In-
DTPA-K(IRDye800)-c(KRGDf) to selectively detect tumor angiogenesis and an
untargeted Cy5.5 to image lymphatics. After acquiring the experimental data,
fluorescence image-guided surgery was performed.
Dynamic, multi-wavelength fluorescence imaging was accomplished using a
liquid crystal tunable filter (LCTF). Excitation light was used for reflectance images
with a LCTF transmitting a shorter wavelength than the peak in the excitation light
spectrum. Therefore, images can be dynamically acquired alternating frame by frame
between emission and excitation light, which should enable image-guided surgery.
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Design techniques for low noise and high speed A/D convertersGupta, Amit Kumar 15 May 2009 (has links)
Analog-to-digital (A/D) conversion is a process that bridges the real analog world to digital
signal processing. It takes a continuous-time, continuous amplitude signal as its input and
outputs a discrete-time, discrete-amplitude signal. The resolution and sampling rate of an
A/D converter vary depending on the application. Recently, there has been a growing
demand for broadband (>1 MHz), high-resolution (>14bits) A/D converters. Applications
that demand such converters include asymmetric digital subscriber line (ADSL) modems,
cellular systems, high accuracy instrumentation, and medical imaging systems. This thesis
suggests some design techniques for such high resolution and high sampling rate A/D
converters.
As the A/D converter performance keeps on increasing it becomes increasingly
difficult for the input driver to settle to required accuracy within the sampling time. This is
because of the use of larger sampling capacitor (increased resolution) and a decrease in
sampling time (higher speed). So there is an increasing trend to have a driver integrated onchip
along with A/D converter. The first contribution of this thesis is to present a new
precharge scheme which enables integrating the input buffer with A/D converter in
standard CMOS process. The buffer also uses a novel multi-path common mode feedback
scheme to stabilize the common mode loop at high speeds.
Another major problem in achieving very high Signal to Noise and Distortion Ratio
(SNDR) is the capacitor mismatch in Digital to Analog Converters (DAC) inherent in the
A/D converters. The mismatch between the capacitor causes harmonic distortion, which
may not be acceptable. The analysis of Dynamic Element Matching (DEM) technique as applicable to broadband data-converters is presented and a novel second order notch-DEM
is introduced. In this thesis we present a method to calibrate the DAC. We also show that a
combination of digital error correction and dynamic element matching is optimal in terms
of test time or calibration time.
Even if we are using dynamic element matching techniques, it is still critical to get the
best matching of unit elements possible in a given technology. The matching obtained may
be limited either by random variations in the unit capacitor or by gradient effects. In this
thesis we present layout techniques for capacitor arrays, and the matching results obtained
in measurement from a test-chip are presented.
Thus we present various design techniques for high speed and low noise A/D
converters in this thesis. The techniques described are quite general and can be applied to
most of the types of A/D converters.
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Statistical Analysis and Dynamic Visualization of Travis Peak Production in the Eastern Texas BasinAyanbule, Babafemi O. 2010 August 1900 (has links)
Gas production has increased exponentially over the last 30 years, which is in
response to the increasing demand for natural gas. This trend is speculated to continue
to increase as legislation continues to be passed requiring power plants to reduce
nitrogen oxide emissions. This recently happened in Colorado according to the
Washington Post, giving more consideration to using natural gas.
As natural gas becomes more popular there is a need to understand the
production patterns and observable trends, integrating data from various sources. This
research will attempt to do just that for wells producing from the Travis Peak formation.
Using data from HPDI L.L.C., (www.hpdi.com) a visual representation was
created for the areal distribution of peak gas rates and cumulative gas production. This
allowed us to categorize wells by their production performance and we found that areas
with relatively high peak gas rates also had high cumulative gas production.
An analysis of these wells was done by completion year, and we found that
wellhead prices of natural gas strongly influenced the annual number of new wells. We
also found that the distribution of the annual number of new wells affected the average
annual initial production rate and the peak gas rate of new wells.
Wells located in areas of poor production performance were analyzed and it was
apparent that newer wells performed relatively better than older ones and well
stimulation is a major requirement for better gas production.
Wells located in areas of good production performance were also analyzed and
we found that the distribution of newer wells to older ones influenced the relative
performance of individual wells.
Overall, there was no observable trend between production variables in Travis
Peak. No trend in production variable was found to be exclusively associated with good
performing wells or poor performing wells.
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Study of the Fatigue Life of Steel Catenary Risers in Interaction with the SeabedNakhaee, Ali 2010 December 1900 (has links)
The fatigue life of a Steel Catenary Riser (SCR) near its touch-down zone is
substantially affected by its interaction with the seabed. Hence, accurate estimate of its
fatigue life requires the understanding and realistic modeling of the interaction between
them.
The interaction between SCR and the seabed depends on many factors, such as soil
properties, riser characteristics, and the development of trenching at the seafloor.
Existing approaches for modeling the seabed in interaction with a SCR approximate the
seabed soil by a linear or nonlinear spring and a dashpot which respectively represent the
stiffness and damping of the soil. However, they do not take into account certain
phenomena resulting from plastic deformation or degradation of the seabed soil, such as
trenching. In this study, a more realistic approach is developed for simulating the
interaction between a SCR and the seabed soil. In addition to the use of a realistic P-y
curve (where P stands for the supporting or resistance force of the seafloor and y for the
vertical penetration of the riser into the soil) to simulate the soil deformation during its interaction with a riser, it considers the development of a trench caused by continuous
poundings of a riser on the seabed and then its feedback effect on the variation of the
bending moment along the riser.
In this study, it has been found that trenching underneath a SCR may decrease the
maximum variation of bending moment near its touch-down zone. Since the variation of
the moment dictates the fatigue damage to the SCR, the results based on this approach
indicate that the trenching development at the seabed may increase the fatigue life of a
SCR and therefore, it may have important application to the design of a SCR.
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The Development of Dynamic Operational Risk Assessment in Oil/Gas and Chemical IndustriesYang, Xiaole 2010 May 1900 (has links)
In oil/gas and chemical industries, dynamics is one of the most essential characteristics
of any process. Time-dependent response is involved in most steps of both
the physical/engineering processes and the equipment performance. The conventional
Quantitative Risk Assessment (QRA) is unable to address the time dependent effect
in such dynamic processes. In this dissertation, a methodology of Dynamic Operational
Risk Assessment (DORA) is developed for operational risk analysis in oil/gas
and chemical industries. Given the assumption that the component performance state
determines the value of parameters in process dynamics equations, the DORA probabilistic
modeling integrates stochastic modeling and process dynamics modeling to
evaluate operational risk. The stochastic system-state trajectory is modeled based on
the abnormal behavior or failure of the components. For each of the possible system-state
trajectories, a process dynamics evaluation is carried out to check whether
process variables, e.g., level, flow rate, temperature, pressure, or chemical concentration,
remain in their desirable regions. Monte Carlo simulations are performed to
calculate the probability of process variable exceeding the safety boundaries. Component
testing/inspection intervals and repair time are critical parameters to define the
system-state configuration; and play an important role for evaluating the probability
of operational failure. Sensitivity analysis is suggested to assist selecting the DORA probabilistic modeling inputs. In this study, probabilistic approach to characterize
uncertainty associated with QRA is proposed to analyze data and experiment results
in order to enhance the understanding of uncertainty and improve the accuracy of
the risk estimation. Different scenarios on an oil/gas separation system were used
to demonstrate the application of DORA method, and approaches are proposed for
sensitivity and uncertainty analysis. Case study on a knockout drum in the distillation
unit of a refinery process shows that the epistemic uncertainty associated with
the risk estimation is reduced through Bayesian updating of the generic reliability
information using plant specific real time testing or reliability data. Case study on
an oil/gas separator component inspection interval optimization illustrates the cost benefit
analysis in DORA framework and how DORA probabilistic modeling can be
used as a tool for decision making. DORA not only provides a framework to evaluate
the dynamic operational risk in oil/gas and chemical industries, but also guides
the process design and optimization of the critical parameters such as component
inspection intervals.
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Optimal Control of Perimeter Patrol Using Reinforcement LearningWalton, Zachary 2011 May 1900 (has links)
Unmanned Aerial Vehicles (UAVs) are being used more frequently in surveillance scenarios for both civilian and military applications. One such application addresses
a UAV patrolling a perimeter, where certain stations can receive alerts at random intervals. Once the UAV arrives at an alert site it can take two actions:
1. Loiter and gain information about the site.
2. Move on around the perimeter.
The information that is gained is transmitted to an operator to allow him to classify the alert. The information is a function of the amount of time the UAV is at the alert site, also called the dwell time, and the maximum delay. The goal of the optimization is to classify the alert so as to maximize the expected discounted information gained by the UAV's actions at a station about an alert. This optimization problem can be readily solved using Dynamic Programming. Even though this approach generates feasible solutions, there are reasons to experiment with different approaches. A
complication for Dynamic Programming arises when the perimeter patrol problem is expanded. This is that the number of states increases rapidly when one adds additional stations, nodes, or UAVs to the perimeter. This in effect greatly increases the computation time making the determination of the solution intractable. The following attempts to alleviate this problem by implementing a Reinforcement Learning technique to obtain the optimal solution, more specifically Q-Learning. Reinforcement Learning is a simulation-based version of Dynamic Programming and requires lesser information to compute sub-optimal solutions. The effectiveness of the policies generated using Reinforcement Learning for the perimeter patrol problem have been corroborated numerically in this thesis.
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Research of Situation and Strategy FormulationChang, Li-Chung 11 June 2004 (has links)
Views of strategy formulation can be mainly divided into two categories. One is I-O(Industrial Organization), the other one is RBV(Resource Based View)(Hitt, Ireland and Hoskisson, 1999¡G2003¡FSe-Hwa Wu, 2000¡FJoseph Shyu, 2000¡FCher-Min Fong, 2001¡FMing-Jer Tang, 2003).Both of vews have each suitable situation. If strategy is formulated from single view, it will cause defects (Robbins, 2003). Recent years, scholars provide solutions from integration¡Bcontingency and dynamic. However, thesis combines 3 features is still few. This paper attempts to find combined views to suit different situation in a dynamic framework. The research provides a static framework included¡G(1) If the contingency of inside and outside company are stable, companies ought to choose ¡uposition-based view¡v; (2)If the contingency of outside company are not stable but stable contingency of inside company, companies ought to choose ¡uvision-based view¡v; (3)If the contingency of outside company are not stable but stable contingency of inside company, companies ought to choose ¡uenvironment-based view¡v; (4)If the contingency of inside and outside company are both not stable, companies ought to choose ¡uresource-based view¡v; (5)If the contingency of inside and outside company are changing smoothly with controllable situation, companies ought to choose ¡uconstruction-based view¡v. The research provides a dynamic framework. From the long term view, a company needs to adjust itself to match the changing of situation in order to have sustainable competitive advantage.
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An analysis of Bullwhip Effect in type of multi-tiers and vertical partition under dynamic situation base on the TFT-LCD industry in TaiwanShen, Ju-Peng 04 July 2005 (has links)
Due to the progress of display manufacturing technology, TFT-LCD (Thin Film
Transistor-Liquid Crystal Display) has been widely put in use gradually such as
monitor¡Blaptop and LCD TV. We also can find TFT-LCD that has already entered the market of the consuming products from IT (Information Technology). And the competition of the panel industry, besides manufacturing technologies, the dynamic demands of upstream, downstream and consumers are related that will effect the performance of panel markers or whole supply chain. Which is called bullwhip effect. Especially, the configuration is vertical partition in Taiwan and the buffwhip effect would be more significant than other countries. This paper discusses the key factors of bullwhip effect and them constructs the system dynamic models to explore the difference. Finally, we will analyze the TFT-LCD members of Taiwan to figure out the decision rules to decrease bullwhip effect.
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