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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
501

Practicality of Discrete Laplace Operators

Thangudu, Kedarnath 27 August 2009 (has links)
No description available.
502

Cooperative Construction

Wang, Zhongkui 10 September 2009 (has links)
No description available.
503

Discrete-time adaptive control of a class of nonlinear systems /

Lee, Keh-ning January 1986 (has links)
No description available.
504

Symmetries in Random Trees

Olsson, Christoffer January 2022 (has links)
No description available.
505

Groundwater Inflow into Fractured Rock Tunnels / Grundvatteninträngning i sprickor i bergtunnlar

Beydoun, Mariam January 2022 (has links)
Groundwater inflow is a challenge in construction of tunnels in fractured bedrocks since it affects the safety function of tunnels and leads to potential problems in the surrounding environment, such as subsidence, dropdown of the groundwater table. Quantification of groundwater inflow into the tunnel is also important for design of grouting in the construction of the tunnel. Modelling groundwater flow in fractured bedrocks currently remains a challenge. Commonly used groundwater models are based on continuum assumptions and they do not consider realistic structures of discrete fractures, which leads to high potential uncertainty in prediction of tunnel groundwater inflow. This thesis focuses on prediction of tunnel groundwater inflow, using a discreet fracture-matrix (DFM) model. The DFM model is evaluated and compared with the conventional continuum model based on Darcy’s law. This DFM model considers, in particular, multi-scale heterogeneity, e.g. fracture networks and variable fracture aperture structures. Applying this DFM model, the impact of variable fracture aperture structures on tunnel inflow is investigated through stochastic analysis. The results show that under the same boundary conditions, the traditional continuum model overestimates the inflow compared to the DFM model. The difference in equivalent permeability is 2 to 3 orders of magnitude. The sensitivity analysis shows that the discreet fracture model is sensitive to the variability of fracture aperture. The estimated equivalent permeability values by discreet fracture modelling is in the order of 5×10-6 to 1×10-7 m/s for a fracture density of 1.2 fractures per square meter. This study demonstrates that the DFM represents the more realistic features of fractured rock structures, which is useful and can be used to predict groundwater inflow in fractured rock tunnels. / Grundvatteninflöde är en utmaning vid byggnation av tunnlar i sprucken berggrund eftersom det påverkar tunnlarnas säkerhetsfunktion och leder till potentiella problem i den omgivande miljön, såsom sättningar och Grundvattennivåsänkning. Kvantifiering av grundvatteninflöde till tunneln är också viktig för utformning av injektering i tätning? byggandet av tunneln. Att modellera grundvattenflödet i sprucken berggrund är för närvarande en utmaning. Grundvattenmodeller man normalt använder är baserade på kontinuumantaganden, och de tar inte hänsyn till realistiska strukturer av diskreta sprickor, vilket leder till hög potentiell osäkerhet i uppskattning av tunnelgrundvatteninflöde. Denna avhandling fokuserar på förutsägelse av tunnelinläckage, med hjälp av en diskret sprickmatris (DFM) modell. DFM-modellen utvärderas och jämförs med den konventionella kontinuummodell vilken är baserad på Darcys lag. Denna DFM-modell tar särskilt hänsyn till multi-skala heterogenitet, till exempel spricknätverk och variabla dubbelkolla. Genom att tillämpa denna DFM-modell undersöks effekten av strukturer med variabel spricköppning på grundvatteninflödet genom stokastisk analys. Resultaten visar att under samma randvillkor överskattar den traditionella kontinuummodellen inflödet jämfört med DFM-modellen. Skillnaden i ekvivalent permeabilitet är 2 till 3 storleksordningar. Känslighetsanalysen visar att den diskreta sprickmodellen är känslig möt variationen i spricköppningen. De uppskattade ekvivalenta permeabilitetsvärdena med diskret sprickmodellering är i storleksordningen 5x10-6 till 1x10-7 m/s för en spricktäthet på 1,2 sprickor per kvadratmeter. Denna studie visar att DFM representerar de mer realistiska egenskaperna hos sprickiga bergstrukturer, vilket är användbart och kan användas för att uppskatta grundvatteninflöde i sprickiga bergtunnlar.
506

The Frequency of Blood Donation in Canada: An Exploration of Individual and Contextual Determinants

Cimaroli, Kristina 10 1900 (has links)
<p>Blood products are used for transfusion in many routine procedures as well as emergency medical care. The balance between the supply and demand of blood products in Canada is being threatened by an increasing aging population, a growing immigrant population, and advances in medical technology which places additional strain on the blood supply. The objective of this research is to investigate the effects of demographic determinants and clinic accessibility on the frequency of blood donation in Canada excluding the province of Québec, providing a national assessment of blood donor correlates at the individual level. Exploration of these demographic factors in addition to clinic accessibility may help to explain why a limited number of repeat donors are currently contributing, with many donors giving blood only once a year. Repeat donors are vital to maintain a safe and secure blood supply, therefore it is important to retain existing donors in addition to recruiting new volunteers. In this study, individual donor and clinic information is obtained from the Canadian Blood Services 2008 national dataset, with contextual data from the 2006 Canadian Census. Discrete choice models are used to assess the effects of these variables on the frequency of blood donation across the country, highlighting the importance of clinic accessibility. The analysis is prepared for major Census Metropolitan Areas in Canada. Results may contribute to service optimization and targeted advertising, ultimately aiming to encourage the eligible population to donate.</p> / Master of Arts (MA)
507

USING A PERFORMANCE EVALUATION TO DETERMINE AN INDIVIDUALIZED INTERVENTION TO INCREASE STAFF TREATMENT INTEGRITY OF DISCRETE TRIAL TEACHING

Dombrowski, Nicholas January 2019 (has links)
Discrete Trial Teaching (DTT) is a teaching method that involves fast-paced trials designed to teach basic skills by breaking them into smaller components, typically conducted in a one-on-one setting. Treatment integrity has proven to be of great importance in DTT, with skill acquisition occurring at higher rates when treatment integrity is high. While research has shown that verbal and written feedback are effective in training staff to conduct DTT, there is still a need for research on the use of individualized interventions based on performance assessments. This study used a multiple-probe across participants design, and demonstrated that a one-on-one session including interventions such as feedback, practice, treatment integrity checklists, and/or antecedent interventions is an effective method for increasing treatment integrity and implementation of DTT. The three participants that took part in the individualized interventions all displayed increases in proficiency of delivering DTT trials. / Applied Behavioral Analysis
508

Probabilistic Supervisory Control of Probabilistic Discrete Event Systems

Pantelic, Vera 04 1900 (has links)
This thesis considers probabilistic supervisory control of probabilistic discrete event systems (PDES). PDES are modeled as generators of probabilistic languages. The probabilistic supervisors employed are a generalization of the deterministic ones previously employed in the literature. At any state, the supervisor enables/disables events with certain probabilities. The probabilistic supervisory control problem (PSCP) that has previously been considered in the literature is revisited: find, if possible, a supervisor under whose control the behavior of a plant is identical to a given probabilistic specification. The existing results are unified, complemented with a solution of a special case and the computational analysis of synthesis problem and the solution. The central place in the thesis is given to the solution of the optimal probabilistic supervisory control problem (OPSCP) in the framework: if the conditions for the existence of probabilistic supervisor for PSCP problem are not satisfied, find a probabilistic supervisor such that the achievable behaviour is as close as possible to the desired behaviour. The proximity is measured using the concept of pseudometric on states of generators. The distance between two systems is defined as the distance in the pseudometric between the initial states of the corresponding generators. The pseudometric is adopted from the research in formal methods community and is defined as the greatest fixed point of a monotone function. Starting from this definition, we suggest two algorithms for finding the distances in the pseudometric. Further, we give a logical characterization of the same pseudometric such that the distance between two systems is measured by a formula that distinguishes between the systems the most. A trace characterization of the pseudometric is then derived from the logical characterization by which the pseudometric measures the difference of (appropriately discounted) probabilities of traces and sets of traces generated by systems, as well as some more complicated properties of traces. Then, the solution to the optimal probabilistic supervisory control problem is presented. Further, the solution of the problem of approximation of a given probabilistic generator with another generator of a prespecified structure is suggested such that the new model is as close as possible to the original one in the pseudometric (probabilistic model fitting). The significance of the approximation is then discussed. While other applications are briefly discussed, a special attention is given to the use of ideas of probabilistic model fitting in the solution of a modified optimal probabilistic supervisory control problem. / Thesis / Doctor of Philosophy (PhD)
509

On Multi-Scale Refinement of Discrete Data

Dehghani Tafti, Pouya 10 1900 (has links)
<p> It is possible to interpret multi-resolution analysis from both Fourier-domain and temporal/spatial domain stand-points. While a Fourier-domain interpretation helps in designing a powerful machinery for multi-resolution refinement on regular point-sets and lattices, most of its techniques cannot be directly generalized to the case of irregular sampling. Therefore, in this thesis we provide a new definition and formulation of multi-resolution refinement, based on a temporal/spatial-domain understanding, that is general enough to allow multi-resolution approximation of different spaces of functions by processing samples (or observations) that can be irregularly distributed or even obtained using different sampling methods. We then continue to provide a construction for designing and implementing classes of refinement schemes in these general settings. The framework for multi-resolution refinement that we discuss includes and extends the existing mathematical machinery for multi-resolution analysis; and the suggested construction unifies many of the schemes currently in use, and, more importantly, allows designing schemes for many new settings. </p> / Thesis / Master of Applied Science (MASc)
510

The Discrete Hodge Star Operator and Poincaré Duality

Arnold, Rachel Florence 16 May 2012 (has links)
This dissertation is a uniïfication of an analysis-based approach and the traditional topological-based approach to Poincaré duality. We examine the role of the discrete Hodge star operator in proving and in realizing the Poincaré duality isomorphism (between cohomology and homology in complementary degrees) in a cellular setting without reference to a dual cell complex. More specifically, we provide a proof of this version of Poincaré duality over R via the simplicial discrete Hodge star defined by Scott Wilson in [19] without referencing a dual cell complex. We also express the Poincaré duality isomorphism over both R and Z in terms of this discrete operator. Much of this work is dedicated to extending these results to a cubical setting, via the introduction of a cubical version of Whitney forms. A cubical setting provides a place for Robin Forman's complex of nontraditional differential forms, defined in [7], in the uniïfication of analytic and topological perspectives discussed in this dissertation. In particular, we establish a ring isomorphism (on the cohomology level) between Forman's complex of differential forms with his exterior derivative and product and a complex of cubical cochains with the discrete coboundary operator and the standard cubical cup product. / Ph. D.

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