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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.
1

Graphics Editor

Zhao, Die January 2007 (has links)
<p>The human enters into the information age in 21st century; the computer science and technology are developed at full speed, and already infiltrate into various field extensively. Resultantly manual drawing gradually is phased out, for those designers who have no prior experience in the computer operation are concerned, they need to have a kind of two-dimensional graphical tool. Graphics editor system arose to the request for designing planar figures for people who have little knowledge in computer.</p><p>This paper describes the development process of this system what is studied for the foundation, utilize object-oriented method to analyze, design with computer figure, and adopt Visual C ++ 6.0 as the developing platform. All these have been finished after 1 month or so. It designs to be two-dimensional graphical software with diverse function which operates simply, easy to study, mutual interface friendly graphics editor system and has satisfied some figure users at present with the new demand as well.</p><p>The following main functions have been realized in this application: It can draw various figures, such as dot, line, circle, arc, parabola and curve, modify them and comprehensive editing. Figure editor includes translation, mirroring, rotating and some similar operations. Comprehensive drawing includes drawing polygon (sealed and arbitrary polygon), round tangent line, round circle contact, line circle contact, some circle contacts and so forth. Meanwhile obtain the point of intersect between the arbitrary crossing, and draw different figures basically according to the points of intersect. By the way, it is capable to cancel and redraw the editing.</p>
2

Graphics Editor

Zhao, Die January 2007 (has links)
The human enters into the information age in 21st century; the computer science and technology are developed at full speed, and already infiltrate into various field extensively. Resultantly manual drawing gradually is phased out, for those designers who have no prior experience in the computer operation are concerned, they need to have a kind of two-dimensional graphical tool. Graphics editor system arose to the request for designing planar figures for people who have little knowledge in computer. This paper describes the development process of this system what is studied for the foundation, utilize object-oriented method to analyze, design with computer figure, and adopt Visual C ++ 6.0 as the developing platform. All these have been finished after 1 month or so. It designs to be two-dimensional graphical software with diverse function which operates simply, easy to study, mutual interface friendly graphics editor system and has satisfied some figure users at present with the new demand as well. The following main functions have been realized in this application: It can draw various figures, such as dot, line, circle, arc, parabola and curve, modify them and comprehensive editing. Figure editor includes translation, mirroring, rotating and some similar operations. Comprehensive drawing includes drawing polygon (sealed and arbitrary polygon), round tangent line, round circle contact, line circle contact, some circle contacts and so forth. Meanwhile obtain the point of intersect between the arbitrary crossing, and draw different figures basically according to the points of intersect. By the way, it is capable to cancel and redraw the editing.
3

Experimental and numerical analysis of orthotropic deformations of wood using Finite Strain Theory (large deformations) and the Finite Element Method (FEM) in 2D

Ren, Honghao January 2021 (has links)
This thesis involves the derivation of a constitutive model under large deformationtheory using Updated Lagrange method applied on an orthotropic material.Thefollowing aspects are included in this thesis work: introduction, theory, FEM implementation, derivation of constitutive model, calibration, result, discussion, conclusion and the future work. This thesis studies the deformation behavior of wood, which is widely used as aconstruction material, in an advanced and more detailed way by analyzing the mechanical properties of wood from both, the application in laboratory and theoreticalcalculation under large deformation theory. A non-linear elastic constitutive model is proposed, derived and calibrated using asimple inverse analysis procedure. The calibration process was performed to identify8 constitutive parameters A1 − A8 of the constitutive model by performing inverseanalysis against relevant experimental data acquired using the Aramis system. Theresults in the comparison were extracted from the specimen when it is both intangential orientation and radial orientation. The project work will be dedicated to the development of a Finite Element Method(FEM) code implemented in MATLAB scripts which was directly used to study themechanical properties of the orthotropic wood material when hyper-elastic behavioris assumed. The results will contain three parts: 1) study of the influence of pith location onthe load required to deform the specimen specimen, 2) reaction force comparisonof the model results against experimental results, and, 3) comparison of the GreenLagrangian strain pattern over the specimen between the experimental data and themodel’s results.
4

Coupled Wave Analysis of Two-Dimensional Second Order Surface-Emitting Distributed Feedback Lasers

Shen, Yangfei 18 May 2016 (has links)
No description available.
5

Two-dimensional Markov chain model for performance analysis of call admission control algorithm in heterogeneous wireless networks

Sha, Sha, Halliwell, Rosemary A., Pillai, Prashant January 2013 (has links)
No / This paper proposes a novel call admission control (CAC) algorithm and develops a two-dimensional markov chain processes (MCP) analytical model to evaluate its performance for heterogeneous wireless network. Within the context of this paper, a hybrid UMTS-WLAN network is investigated. The designed threshold-based CAC algorithm is launched basing on the user’s classification and channel allocation policy. In this approach, channels are assigned dynamically in accordance with user class differentiation. The two-dimensional MCP mathematical analytic method reflects the system performance by appraising the dropping likelihood of handover traffics. The results show that the new CAC algorithm increases the admission probability of handover traffics, while guarantees the system quality of service (QoS) requirement.
6

Mesoscopic quantum interference experiments in InGaAs and GaAs two-dimensional systems

Ren, Shaola 16 June 2015 (has links)
The study of quantum interference in solid-state systems yields insight in fundamental properties of mesoscopic systems. Electron quantum interference constitutes an important method to explore mesoscopic physics and quantum decoherence. This dissertation focuses on two-dimensional (2D) electron systems in $delta-$Si doped n-type In$_{0.64}$Ga$_{0.36}$As/In$_{0.45}$Al$_{0.55}$As, 2D hole systems in Si-doped p-type GaAs/Al$_{0.35}$Ga$_{0.65}$As and C-doped p-type GaAs/\Al$_{0.24}$Ga$_{0.76}$As heterostructures. The low temperature experiments study the magnetotransport of nano- and micro-scale lithographically defined devices fabricated on the heterostructures. These devices include a single ring interferometer and a ring interferometer array in 2D electron system, Hall bar geometries and narrow wires in 2D hole systems. The single ring interferometer yields pronounced Aharonov-Bohm (AB) oscillations with magnetic flux periodicity of h/e over a wide range of magnetic field. The periodicity was confirmed by Fourier transformation of the oscillations. The AB oscillation amplitude shows a quasi-periodic modulation over applied magnetic field due to local magnetic flux threading through the interferometer arms. Further study of current and temperature dependence of the amplitude of the oscillations indicates that the Thouless energy forms the measure of excitation energies giving quantum decoherence. An in-plane magnetic field was applied to the single ring interferometer to study the Berry's phase and the Aharonov-Casher effect. The ring interferometer array yields both AB oscillations and Altshuler-Aronov-Spivak (AAS) oscillations, the latter with magnetic flux periodicity of h/2e. The AAS oscillations require time-reversal symmetry and hence can be used to qualify time-reversal symmetry breaking. More importantly, the fundamental mesoscopic dephasing length associated with time-reversal symmetry breaking under applied magnetic field, an effective magnetic length, can be obtained by the analysis of the AAS oscillations over magnetic field. A theoretical model for confined ballistic system is confirmed by experimental data fitting. The AAS oscillations are barely resolved above 0.16 T and their amplitude decays with increasing magnetic field. The AB oscillations exist till above 2 T and their amplitude doesn't show the monotonic decay with increasing magnetic field. The different behavior of the AAS and AB oscillations originates in the different symmetries, respectively temporal and spatial, that they are sensitive to. The p-type 2D GaAs system has strong spin-orbit interaction (SOI). Antilocalization in a Hall bar geometry was analyzed by the 2D Hikami-Larkin-Nagaoka (HLN) theory to obtain the spin coherence time and phase coherence time. The 2D hole systems we studied have low density and high mobility, quite different from the 2D electron systems. These high-quality 2D hole systems demonstrate semi-classical ballistic phenomena in mesoscopic structures preferentially to quantum-coherence phenomena. / Ph. D.
7

New Models for Crowd Dynamics and Control

Al-nasur, Sadeq J. 19 December 2006 (has links)
In recent years, there has been an increasing interest in modeling crowd and evacuation dynamics. Pedestrian models are based on macroscopic or microscopic behavior. In this work, we are interested in developing models that can be used for evacuation control strategies. Hence, we use macroscopic modeling approach, where pedestrians are treated in an aggregate way and detailed interactions are overlooked. In this dissertation, we developed two-dimensional space crowd dynamic models to allow bi-directional low by modifying and enhancing various features of existing traffic and fluid dynamic models. In this work, four models based on continuum theory are developed, and conservation laws such as the continuity and momentum equations are used. The first model uses a single hyperbolic partial differential equation with a velocity-density relationship, while the other three models are systems of hyperbolic partial differential equations. For one of the system models presented, we show how it can be derived independently from a microscopic crowd model. The models are nonlinear, time-varying, hyperbolic partial differential equations, and the numerical simulation results given for the four macroscopic models were based on computational fluid dynamics schemes. We also started an initial control design that synthesizes the feedback linearization method for the one-dimensional traffic flow problem applied directly on the distributed parameter system. In addition, we suggest and discuss the information technology requirements for an evacuation system. This research was supported in part from the National Science Foundation through grant no. CMS-0428196 with Dr. S. C. Liu as the Program Director. This support is gratefully acknowledged. Any opinion, findings, and conclusions or recommendations expressed in this study are those of the writer and do not necessarily reflect the views of the National Science Foundation. / Ph. D.
8

Development of control strategies for Francisella noatunensis subsp. orientalis in Nile tilapia, Oreochromis niloticus

Shahin, Khalid Elsayed Kamal Elsayed January 2018 (has links)
Nile tilapia, Oreochromis niloticus, is one of the most important farmed fish globally. One of the most serious bacterial diseases constraining global tilapia production is Francisellosis caused by Francisella noatunensis subsp. orientalis (Fno). Although outbreaks of Fno are increasing worldwide, there are no licenced commercial vaccines to prevent the disease for use on tilapia farms. Thus, the current treatment of choice is the use of antibiotics combined with increasing water temperature up to 30°C. Studies investigating the diversity of circulating Fno isolates and the immune response of tilapia elicited by vaccination against piscine francisellosis are lacking. In addition, the current conventional and molecular tools used for detection of Fno have many drawbacks, making detection of Fno a challenging process. In this study, five clinical isolates of Fno from diverse geographical locations (UK, Costa Rica, Mexico, Japan and Austria), previously characterised by morphology, genotype, antimicrobial susceptibility and virulence, were used in a proteomic study. The whole proteomic cell profile of the five isolates were homogenous by one-dimension sodium dodecyl polyacrylamide gel electrophoresis (1D-SDS-PAGE), while minor differences in the intensity of 15 proteins between the strains were observed by two-dimension SDS-PAGE (2DE), including some important virulence related proteins. The UK isolate was the most significantly different isolate when compared to the other Fno isolates in the current study. The Fno UK isolate had significantly higher abundance of 10/15 of the significantly expressed proteins including four of the essential pathogenicity and virulence related proteins (IglC, GroEL, DnaK, ClpB) compared to the other used Fno isolates. The antigenic profiles of the five Fno isolates were studied by 1D western blotting using tilapia hyper immune sera which recognised an immunodominant band of a molecular weight of ~ 17-28 kDa in all tested Fno isolates. Liquid chromatography-electrospray ionization-tandem mass spectrometry (LC/ESI/MS/MS) identified 47 proteins in this antigenic band. Some of the identified proteins are associated with Fno pathogenicity. 2D western blot analysis of the vaccine isolate (Fno UK) revealed differential antigen recognition between sera from vaccinated and non-vaccinated fish following experimental challenge (26 antigenic spots recognised by sera from vaccinated fish; 31 antigenic spots recognised by sera from vaccinated and challenged fish and 30 antigenic spots recognised by non-vaccinated and challenged fish). The identity of these proteins was determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and some of them are known Francisella virulence related proteins. Bioinformatics analyses revealed diverse categories of proteins with high biological functions, however the vast majority of these proteins are involved in energy production and metabolic pathways of the bacteria. This detailed analysis will facilitate the development of cross-strain protective subunit Fno vaccines and antigen-targeted Fno diagnostics. The outer membrane proteins (OMPs) of the same five Fno isolates were extracted using the ionic detergent sarkosyl. The OMP fraction of the different isolates were separated via 1D-SDS PAGE and the digested peptides of the UK isolate were analysed by LC/ESI/MS/MS. High degree of similarity was observed in the OMP profile of the five Fno isolates with an abundant protein band at 17-28 kDa, which was found to be antigenic by 1D western blot using convalescent tilapia sera. LC/ESI/MS/MS analysis of the OMPs of the Fno UK isolate identified 239 proteins, including 44 proteins in the antigenic band (17-28 kDa). Comparison between the proteins identified in the immunogenic band of whole cell lysate and OMP fraction of the Fno UK isolate showed 30 common proteins between the two preparations, 17 proteins were identified only in the whole cell extract and 14 were identified only in OMP fraction. Outer membrane proteins (e.g. Omp-A), virulence related proteins such (e.g. IglC) and other stress related proteins (e.g. AhpC/TSA family peroxiredoxin) were more abundant in the OMP fraction than the whole cell lysate. In silico analysis enabled prediction of the function and location of the OMPs identified by Mass-spectrometry. The findings of this study provide preliminary data on bacterial surface proteins that exist in direct contact with the host immune defence during infection and offering an insight into their potential role as novel targets for Fno diagnostics and vaccine development. The efficacy of an injectable whole cell oil-adjuvanted vaccine was evaluated against challenge with heterologous Fno isolates in Nile tilapia, Oreochromis niloticus. Three duplicate groups of 130 healthy Nile tilapia (~15 g) were intraperitoneally (i.p.) injected with the vaccine, adjuvant-alone or PBS followed by an i.p. challenge with three Fno isolates from geographically distinct locations. The vaccine provided significant protection to all immunised tilapia groups with a significantly higher relative percent survival (RPS) of 82.3% against homologous challenge, compared to 69.8% and 65.9% after heterologous challenge. Protection correlated with significantly elevated specific antibody responses and western blot analysis demonstrated cross-isolate antigenicity with sera from fish post-vaccination and post-challenge. Moreover, a significantly lower bacterial burden was detected by quantitative real-time polymerase chain reaction (qPCR) in conjunction with significantly greater expression of IgM, IL-1β, TNF-a and MHCII 72 hours post-vaccination (hpv) in spleen samples from vaccinated tilapia compared to those of adjuvant-alone and control fish. The latter results suggested stimulation of protective immune responses following vaccination. In addition, a whole cell formalin killed autogenous immersion vaccine against Fno was developed using the same isolate used for the injectable vaccine. Duplicate tanks of 35 tilapia fry were immersed in the vaccine or in sterile Modified Muller Hinton broth (MMHB) diluted in tank water (1:10 dilution) for 30 s and at 30 days post-vaccination (dpv), all fish groups were immersion challenged with the homologous Fno isolate and monitored for 21 days. A moderate RPS of 43.7% was provided by the vaccine. Serum IgM levels were below the threshold in 30 % of the vaccinated fry 30 dpv. Also, the IgM levels of the vaccinated fry were not significantly different from control fry 21 days-post challenge. A recombinase polymerase amplification (RPA) assay was developed and validated for rapid detection of Fno. The RPA reaction was performed at a constant temperature of 42°C for 20 min. The RPA assay was performed using a quantitative plasmid standard containing a unique Fno gene sequence. Validation of the assay was performed not only by using DNA from Fno, closely related Francisella species and other common bacterial pathogens in fish farms, but also by screening 78 Nile tilapia and 5 water samples collected from UK and Thailand. All results were compared with those obtained by previously established real-time qPCR. The developed RPA showed high specificity in detection of Fno with no cross-detection of either the closely related Francisella spp. or the other species of bacteria tested. The Fno-RPA performance was highly comparable to the published qPCR with detection limits at 15 and 11 DNA molecules detected, respectively. The Fno-RPA was rapid, giving results in approximately 6 min in contrast to the qPCR that required approximately 90 min to reach the same detection limits. Moreover, the RPA was more tolerant to reaction inhibitors than qPCR when tested with field samples. The fast reaction, simplicity, cost-effectiveness, sensitivity and specificity make the RPA an attractive diagnostic tool that will contribute to control the infection through prompt on-site detection of Fno. The overall results of this study indicated that Fno isolates from different origins share a high degree of homology in their proteomic and antigenic profile. Proteomic characterisation data of Fno isolates has contributed to understanding the diversity of Fno isolates and assisted in identifying suitable candidates for developing an effective Fno vaccine. / Moreover, this study has proven the efficacy of a cross protective Fno injection vaccine in tilapia fingerlings, with further optimisation needed for immersion vaccination of fry, and given insights into the immune response of tilapia to vaccination against francisellosis. In addition, it provided a rapid, sensitive, specific and robust molecular tool for detection of Fno that can assist surveillance and control of piscine francisellosis on tilapia farms.
9

[en] USE OF ADAPTIVE ARRAYS IN CDMA SYSTEMS / [es] UTIZACIÓN DE ANTENAS ADAPTATIVAS EN SISTEMAS CDMA / [pt] UTILIZAÇÃO DE ANTENAS ADAPTATIVAS EM SISTEMAS CDMA

MAURICIO VILELA GUERRA 23 October 2001 (has links)
[pt] Este trabalho tem como objetivo avaliar alguns aspectos da utilização de antenas adaptativas em um sistema celular digital CDMA. Uma das razões para isto é que as antenas adaptativas reduzem a interferência que no sistema CDMA influencia direta e fortemente a capacidade do sistema. Inicialmente foi feito um resumo dos princípios gerais dos arranjos de antenas de sistemas celulares digitais e de algoritmos de adaptação. Com base nestes princípios, é analisada a aplicação específica a sistemas CDMA, estabelecendo-se uma modelagem do receptor incluindo o receptor Rake. É avaliado então através de simulação o comportamento de dois importantes métodos de filtragem espacial adaptativa para sistemas CDMA. / [en] This work aims to evaluate some aspects of the use of adaptive arrays in digital celular CDMA systems. One reason for that is that adaptive arrays reduce the interference which strongly affects the performance of the system. First the general principles of adaptive antennas, digital cellular systems and adaptation algorithm are sumarized. Based on that principles, the application to CDMA systems is addressed, and a receiver model is developed, including the Rake receiver. Then the behavior of two filtering techniques is evaluated through computer simulation. / [es] Este trabajo tiene como objetivo evaluar algunos aspectos de la utilización de antenas adaptativas en un sistema celular digital CDMA. Una de las razones para esto es que las antenas adaptativas reducen la interferencia, que en el sistema CDMA influeye directa y fuertemente em la capacidad del sistema. Inicialmente se realizó un resumen de los principios generales de los arranjos de antenas de sistemas celulares digitales y de algoritmos de adaptación. Con base en estos princípios, se analiza la aplicación específica a sistemas CDMA, estableciendo una modelaje del receptor incluindo el receptor Rake. Se evalúa a través de simulación el comportamiento de dos importantes métodos de filtraje espacial adaptativa para sistemas CDMA.

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