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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.
51

Building Cloud-Based Information Systems Lab Architecture: Deriving Design Principles that Facilitate the Effective Construction and Evaluation of a Cloud-Based Lab Environment

Trevethan, Thomas J. 01 January 2015 (has links)
The problem explored in this dissertation report was that at the time of this study, there were no design principles or methodologies based on design science research (DSR) available to use for artifact construction, implementation, and effective evaluation of cloud-based networking lab environments that can be used to foster hands-on technology skills in students. Primarily based on Hevner’s 7 guidelines of DSR, Peffer’s design science research methodology (DSRM), and Gregor’s IS design theory, this study forms the groundwork for the development of procedures and specifications derived from DSR literature to facilitate the construction, implementation, and evaluation of a comprehensive cloud-based computer and information systems (CIS) laboratory artifact that is globally accessible 24 hours a day and 7 days a week. Secondarily, this study guided the construction and implementation of a prototype cloud-based lab environment using the procedures and specifications derived from DSR. The cloud-based lab environment was then evaluated based on the skill level attained by students enrolled in courses that leveraged the proposed system. Results of this study showed that the overwhelming majority of the students who participated in the experiment using the cloud-based lab environment showed statistically significant gains in pretest and posttest scores compared to the students who participated in the experiment using the classroom-based physical equipment. These results fully supported the first hypothesis for this study, that participation in the cloud-based lab environment would promote positive student outcomes. The second hypothesis also was supported. The majority of the experimental group students completed most of the labs and significantly spent more time on the system compared to the control group students using the traditional classroom-based physical lab equipment, which indicated the specifications derived from DSR positively influenced the use of the cloud-based system. An argument was made that the proposed study advances IS and education research through artifact construction and evaluation by correlating Hevner’s 7 steps of effective DSR theory, Peffer’s DSRM, and Gregor’s IS design theory to the problem statement, research questions, and hypothesis in order to develop guiding principles and specifications for building and assessing a cloud-based lab environment.
52

Building a simulation toolkit for wireless mesh clusters and evaluating the suitability of different families of ad hoc protocols for the Tactical Network Topology

Karapetsas, Konstantinos 03 1900 (has links)
Approved for public release, distribution is unlimited / Wireless mesh networking has emerged as the successor of the traditional ad hoc networks. New technological advances, the standardization of protocols and interfaces and the maturity of key components have made it possible for current mesh research groups to set goals that are really close to the world's expectations. The objective of this research is to design and implement a simulation toolkit for wireless mesh clusters that can be used as an additional performance evaluation technique for the Tactical Network Topology program of Naval Postgraduate School. This toolkit is implemented in the OPNET simulation environment and it incorporates various nodes running different ad hoc routing protocols. Furthermore, the investigation of a suitable combination of protocols for the Tactical Network Topology is achieved by creating scenarios and running a number of simulations using the mesh toolkit. / Captain, Hellenic Air Force
53

Topics In Noncommutative Gauge Theories And Deformed Relativistic Theories

Chandra, Nitin 07 1900 (has links) (PDF)
There is a growing consensus among physicists that the classical notion of spacetime has to be drastically revised in order to nd a consistent formulation of quantum mechanics and gravity. One such nontrivial attempt comprises of replacing functions of continuous spacetime coordinates with functions over noncommutative algebra. Dynamics on such noncommutative spacetimes (noncommutative theories) are of great interest for a variety of reasons among the physicists. Additionally arguments combining quantum uncertain-ties with classical gravity provide an alternative motivation for their study, and it is hoped that these theories can provide a self-consistent deformation of ordinary quantum field theories at small distances, yielding non-locality, or create a framework for finite truncation of quantum field theories while preserving symmetries. In this thesis we study the gauge theories on noncommutative Moyal space. We nd new static solitons and instantons in terms of the so-called generalized Bose operators (GBO). GBOs are constructed to describe reducible representation of the oscillator algebra. They create/annihilate k-quanta, k being a positive integer. We start with giving an alternative description to the already found static magnetic flux tube solutions of the noncommutative gauge theories in terms of GBOs. The Nielsen-Olesen vortex solutions found in terms of these operators also reduce to the ones known in the literature. On the other hand, we nd a class of new instanton solutions which are unitarily inequivalent to the ones found from ADHM construction on noncommutative space. The charge of the instanton has a description in terms of the index representing the reducibility of the Fock space representation, i.e., k. After studying the static soliton solutions in noncommutative Minkowski space and the instanton solutions in noncommutative Euclidean space we go on to study the implications of the time-space noncommutativity in Minkowski space. To understand it properly we study the time-dependent transitions of a forced harmonic oscillator in noncommutative 1+1 dimensional spacetime. We also provide an interpretation of our results in the context of non-linear quantum optics. We then shift to the so-called DSR theories which are related to a different kind of noncommutative ( -Minkowski) space. DSR (Doubly/Deformed Special Relativity) aims to search for an alternate relativistic theory which keeps a length/energy scale (the Planck scale) and a velocity scale (the speed of light scale) invariant. We study thermodynamics of an ideal gas in such a scenario. In first chapter we introduce the subjects of the noncommutative quantum theories and the DSR. Chapter 2 starts with describing the GBOs. They correspond to reducible representations of the harmonic oscillator algebra. We demonstrate their relevance in the construction of topologically non-trivial solutions in noncommutative gauge theories, focusing our attention to flux tubes, vortices, and instantons. Our method provides a simple new relation between the topological charge and the number of times the basic irreducible representation occurs in the reducible representation underlying the GBO. When used in conjunction with the noncommutative ADHM construction, we nd that these new instantons are in general not unitarily equivalent to the ones currently known in literature. Chapter 3 studies the time dependent transitions of quantum forced harmonic oscillator (QFHO) in noncommutative R1;1 perturbatively to linear order in the noncommutativity . We show that the Poisson distribution gets modified, and that the vacuum state evolves into a \squeezed" state rather than a coherent state. The time evolutions of un-certainties in position and momentum in vacuum are also studied and imply interesting consequences for modelling nonlinear phenomena in quantum optics. In chapter 4 we study thermodynamics of an ideal gas in Doubly Special Relativity. We obtain a series solution for the partition function and derive thermodynamic quantities. We observe that DSR thermodynamics is non-perturbative in the SR and massless limits. A stiffer equation of state is found. We conclude our results in the last chapter.
54

Reologické vlastnosti asfaltových pojiv / Rheological properties of binders

Hotař, Petr January 2014 (has links)
The comparison of rheological properties (complex shear modulus and phase angle and dynamic viscosity) of four paving bitumens and two polymer modified bitumens is performed in this diploma thesis. Furthermore, the empirical tests (needle penetration and softening point) were determined on these binders. Effect of asphalt binders aging was modeled using RTFOT test and modified RTFOT test (3 x RTFOT).
55

Problematika stárnutí asfaltových pojiv a směsí / Ageing of asphalt binders and mixtures

Štěpanovský, Vlastimil January 2015 (has links)
Diploma thesis is particularly focused on ageing of asphalt mixtures and asphalt binders. In the theoretical part an array of methods simulating short term and long term ageing consequently is introduced. The main objective of the practical part was to carry out the long-term ageing test method BSA (Braunschweiger Alterung). Thereafter, specimens testing for stiffness properties according to CSN EN 12697-26 were made. After conducting the measurement on those, asphalt binder was extracted and processed to follow-up testing. The testing consisted of a range of methods – Penetration CSN EN 1426, Ring and Ball test CSN EN 1427, Determination of the Frass breaking point CSN EN 12593, Determination of complex shear modulus CSN EN 14770 and Dynamic viscosity using a dynamic shear rheometer (DSR). The given results were assessed in the last part in order to evaluate the rate of the binder degradation caused by the method BSA.
56

Využití přísady vhodné pro dodatečnou modifikaci asfaltové směsi / Use of an additive suitable for additional modification of the asphalt mixture

Machová, Sára January 2022 (has links)
This thesis deals with the modification of asphalt binder 50/70 with fast reacting SBS. This is a relatively new additive that should be able to improve the binder properties during mixing of the asphalt mix at the plant. In the theoretical part, the issue of asphalt-mixing plant and polymer modification additives is presented. Furthermore, the test methods used such as needle penetration, softening point, determination of the elastic recovery, DSR and MSCR are described. Several modified binder samples were developed for the tests, in which mixing temperature, mixing time and SBS content were combined. The results of each test were compared and evaluated at the end of the thesis.
57

Možnosti mísení pojiv typu PMB RC s pojivem z R-materiálu / Possibility of mixing PMB RC type binders with reclaimed binder from RAP

Trnka, Lukáš Unknown Date (has links)
The diploma thesis deals with the possibility of mixing binders of the PMB RC type with a binder made of reclaimed ashalt. lists the types of asphalt binders, its production and modification are in the teoretical part. There is explained the principle of rejuvenators function, types of rejuvenators. The procedures for performing tests on asphalt binders: recovery of asphalt binder, needle penetration, softening point (ring and ball method), reversible ductility, breaking point (according to Fraass) and DSR. Individual tests are evaluated and asphalt mixtures are compared in the practical part of asphalt binder. The diploma thesis deals with the possibility of mixing binders of the PMB RC type with a binder made of reclaimed ashalt. lists the types of asphalt binders, its production and modification are in the teoretical part. There is explained the principle of rejuvenators function, types of rejuvenators. The procedures for performing tests on asphalt binders: recovery of asphalt binder, needle penetration, softening point (ring and ball method), reversible ductility, breaking point (according to Fraass) and DSR. Individual tests are evaluated and asphalt mixtures are compared in the practical part of asphalt binder.
58

A Diffuse Spectral Reflectance Library of Clay Minerals and Clay Mixtures within the VIS/NIR Bands

Vlack, Yvette A. 18 November 2008 (has links)
No description available.
59

Reologické vlastnosti asfaltových pojiv / Rheological properties of asphalt binders

Coufalík, Pavel Unknown Date (has links)
Dissertation thesis is focused on rheological properties of asphalt binders and on changes of their performance during the lifetime in road structures. Aging processes of asphalt binders and methods of laboratory aging are described in the theoretical part of the thesis. Furthermore, basic rheological models and related test methods for the evaluation of asphalt binders are described. In the practical part, properties of asphalt binders are investigated after aging process and their performance is evaluated by empirical and functional test methods. The various methods of aging are compared with each other and a relationship between real conditions and laboratory aging is researched. In the next section, vacuum flashed cracked residue (VFCR) is added to the selected asphalt binders and their influence on rheological properties during description of aging of asphalt binders is investigated. The results were used in publication of two certified methodology under the title „The methodology for the evaluation of paving bitumen in terms of susceptibility to thermal oxidative aging“ and „The methodology describes laboratory aging of asphalt mixtures“. The results of the thesis are listed in the conclusion.
60

Dávkování oživovacích přísad do asfaltové směsi s vysokým obsahem R-materiálu / Dosage of rejuvenating agents to asphalt mixture with high content of RAP

Čumíčková, Markéta January 2019 (has links)
The diploma thesis is focused on the appropriate dosage of rejuvenating agents in asphalt mixtures with high content of RAP. The empirical and functional laboratory tests are described in the theoretical part. The practical part deals with the estimation of the optimal amount of rejuvenating agents by means of laboratory tests so that the rheological properties of the degraded asphalt binder can be restored by suitable dosing into the RAP. As part of the TAČR ZÉTA project, an experimental section of asphalt mixture containing 50 % of the RAP and an appropriate amount of the rejuvenating agents was created. The aim of the thesis is to find an optimal dosage of the rejuvenating agents in the samples of the RAP and laboratory aged asphalt binder of gradation 50/70, to determine the effectiveness of selected rejuvenating agents and to monitor changes in the parameters of the experimental section during the period of time.

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