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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.
221

Creating and Utilizing Online Assignments in a Calculus Class

Jungic, Veselin, Kent, Deborah, Menz, Petra 17 April 2012 (has links)
The aims of this paper are to present some of the findings about the creation and utilization of online assignments and choice of support software for several calculus classes at Simon Fraser University (SFU) by considering the needs and perspectives of the instructors, students, and administrators. The term online assignment is used for a set of problems that are posted, submitted, graded, and recorded electronically through a course learning management system (LMS) of choice. The purpose of this note is to contribute to the discussion about a common question detected among research papers on the theme of online assignments; how can technology be used in teaching so that students benefit the most? Questions are provided to guide an instructor in choosing online assignment problems, and a list of necessary skills is supplied for an instructor to be able to deal effectively with this pedagogical tool.
222

Real-time Structural Health Monitoring of Nonlinear Hysteretic Structures

Nayyerloo, Mostafa January 2011 (has links)
The great social and economic impact of earthquakes has made necessary the development of novel structural health monitoring (SHM) solutions for increasing the level of structural safety and assessment. SHM is the process of comparing the current state of a structure’s condition relative to a healthy baseline state to detect the existence, location, and degree of likely damage during or after a damaging input, such as an earthquake. Many SHM algorithms have been proposed in the literature. However, a large majority of these algorithms cannot be implemented in real time. Therefore, their results would not be available during or immediately after a major event for urgent post-event response and decision making. Further, these off-line techniques are not capable of providing the input information required for structural control systems for damage mitigation. The small number of real-time SHM (RT-SHM) methods proposed in the past, resolve these issues. However, these approaches have significant computational complexity and typically do not manage nonlinear cases directly associated with relevant damage metrics. Finally, many available SHM methods require full structural response measurement, including velocities and displacements, which are typically difficult to measure. All these issues make implementation of many existing SHM algorithms very difficult if not impossible. This thesis proposes simpler, more suitable algorithms utilising a nonlinear Bouc-Wen hysteretic baseline model for RT-SHM of a large class of nonlinear hysteretic structures. The RT-SHM algorithms are devised so that they can accommodate different levels of the availability of design data or measured structural responses, and therefore, are applicable to both existing and new structures. The second focus of the thesis is on developing a high-speed, high-resolution, seismic structural displacement measurement sensor to enable these methods and many other SHM approaches by using line-scan cameras as a low-cost and powerful means of measuring structural displacements at high sampling rates and high resolution. Overall, the results presented are thus significant steps towards developing smart, damage-free structures and providing more reliable information for post-event decision making.
223

Extension du concept "One-column" au lit mobile simulé réactif : application à la séparation réactive des C8 aromatiques / Extension of the "One-column" concept to reactive simulated moving bed processes : application to C8 aromatics reactive separation

Bergeot, Ghislain 04 November 2010 (has links)
La séparation des C8 aromatiques par Lit Mobile Simulé (LMS) permet d'obtenir du paraxylène (PX) pur. Les autres composés du mélange sont recyclés dans un réacteur afin d'être isomérisés puis séparés à nouveau. La charge du LMS est composée à environ 75% par ce flux de recyclage. L'intégration de la réaction dans le LMS, réalisée en intercalant des réacteurs d'isomérisation entre les lits d'adsorbant de la zone 3 (procédé LMS Réactif, LMSR), doit permettre une réduction de ce flux de recyclage.L'objectif de cette thèse est de développer une méthodologie d'étude des procédés de type Lit Mobile Simulé (LMS) et Lit Mobile Simulé Réactif (LMSR) basée sur :-un outil expérimental simplifié : le pilote One-column réactif (OCR)-des simulateurs One-column réactif ou non qui seront validés par les résultats expérimentaux du pilote-des simulateurs LMS et LMSR permettant d'accéder aux résultats des procédés industriels.Les simulations de One-column (OC) montrent une bonne sensibilité aux paramètres clés de la séparation des C8 aromatiques (sélectivité PX/EB et diffusion intracristalline). Les résultats expérimentaux font ressortir des difficultés importantes à mettre en œuvre le OC expérimentalement. Plusieurs hypothèses sont exposées pour expliquer les résultats obtenus mais les difficultés rencontrées limitent, en l'état, l'utilisation du pilote pour l'étude de la séparation (réactive ou non) des C8 aromatiques.L'étude du LMSR effectuée par simulation montre l'importance du nombre et de l'emplacement des réacteurs ainsi que de l'intégration du LMSR dans la boucle de production de PX. L'usage du LMSR pour la production de PX permet une réduction importante du débit de recyclage / Today, pure paraxylene (PX) is mainly obtained from a mix of C8 aromatics by a separation process based on adsorption: the Simulated Moving Bed (SMB). The other components of the blend are sent to an isomerisation reactor and are recycled to the SMB. 75% of the SMB feed flow rate come from this recycle flow. Coupling reaction and separation by inserting isomerisation reactors between the adsorption beds of the third zone (Simulated Moving Bed Reactor, SMBR) should allow a reduction of this recycling flow rate.The main objective of this thesis is to develop a new methodology for studying SMB and SMBR processes based on:- a simplify experimental tool : the One-column reactive (OCR) pilot unit- simulators of the OCR which will be validated by the experimental results obtain on the pilot unit- simulators of SMB and SMBR processes which give access to industrial processes results.Simulation results show that OC system seem to be sensitive to key parameters of C8 aromatics separation (PX/EB selectivity and micropore diffusivity). Results on the pilot unit highlight the difficulties to implement an experimental OC. Hypothesis are given to explain those results but, without modification, OCR pilot unit cannot be used to study xylene separation (with or without reaction).SMBR study done by simulation shows the impact of the placement and the number of reactors. Integration of SMBR in the global PX production scheme is also essential. SMBR allows an important reduction of recycling flow rate (up to 50%).
224

Controle de propriedades de filmes finos de óxido de alumínio através da assistência de feixe iônico / Controlling aluminum oxide thin films properties through ion beam assistance.

Santos, Thales Borrely dos 28 April 2017 (has links)
Este trabalho tem por objetivo a caracterização de filmes finos de óxido de alumínio produzidos por deposição assistida por feixe de íons Ar+. Tal caracterização consiste em estabelecer a relação entre os parâmetros de produção (energia do feixe e uxo relativo de Ar), a composição e a estrutura dos lmes. Para tanto, utiliza-se técnicas de microscopia de força atômica, difração de raios-x, reetividade de raios-x e análise por feixe iônico. Resultados mostram que amostras produzidas à temperatura ambiente e à 450 oC são amorfas independentemente da energia do feixe iônico. Filmes formados com assistência de feixe possuem qualidade superior àqueles formados por deposição física de vapor. O bombardeamento de íons Ar+ mostra-se capaz de controlar a concentração de hidrogênio, a estequiometria, a rugosidade, o tamanho dos grãos e a densidade dos lmes nos. Amostras com excelente qualidade baixa rugosidade, estequiometria próxima da ideal e boa densidade foram produzidas utilizando íons com energia dentre 300 eV e 600 eV. / The scope of this work is the characterization of aluminum oxide thin films produced by Ar+ ion beam assisted deposition. This characterization consists in establishing the relationship between production parameters (ion beam energy and argon relative ux), structure and composition of these lms. In order to undertake this task, the following techniques were used: atomic force microscopy, x-ray diraction, x-ray reectivity and ion beam analysis. Results show that samples produced at room temperature and at 450 oC are amorphous regardless the ion beam energy. Films grown under ion assistance have better characteristics than the ones deposited by physical vapor deposition. The ion beam bombardment is capable of controlling hydrogen concentration, stoichiometry, roughness, grain size and density of alumina samples. High quality lms at surface and increased density lms with near ideal stoichiometry were produced with 300 eV and 600 eV ion beam energy.
225

Design av en digital utbildningsmodul med kristermer på svenska och norska : Hur utformas utvärdering av lärande? / Design of a digital ecucation modele with crisis terms in Swedish an Norwegian : How to design evaluation of learning?

Norén Persson, Erika January 2018 (has links)
CriseIT är ett projekt som arbetar med att bidra till god krisberedskap genom att skapa mindre gränsregionala hinder i krisövningar över den svenska och norska gränsen mellan Värmland och Hedmarks Fylke. I tidigare krisövningar över gränsen har det varit tydligt att det uppstår språkliga barriärer. Därför har en parlör tagits fram i syfte att överbrygga dessa hinder. Syftet med detta arbete i att designa en digitalt utbildningsmodul är att ta reda på hur man kan lägga upp en utbildning som hjälper användaren i att öva på svenska och norska kristermer. Det kan vara genom att lära sig ord utantill eller genom att öva på att söka på ord och begrepp i parlören. Som metod användes ett pilottest med 11 deltagare från området krisledningsövning av en prototyp innehållande ett par olika typer av ordinlärningsfrågor samt ett kortare frågeformulär. Pilottestet gjordes på distans via det webbaserat systemet Ozlab. Upplägget av frågorna i utbildningsdelen i pilottestet fungerar övervägande bra som ett sätt att lära sig ord och som en övning i att leta på ord och begrepp i ordlistan. I slutsatserna diskuteras lämpligt LMS (Learning Management System) för en sådan utbildningsmodul. Testpersonernas kommentarer var övervägande positiva kring parlören och att hitta svar i den till utbildningsmodulen. Bland de brister som uppmärksammades var själva sökfunktionen i den pdfbaserade parlören. Det ges även synpunkter kring utveckling av parlören.
226

Channel sparsity aware polynomial expansion filters for nonlinear acoustic echo cancellation

Vinith Vijayarajan (5930993) 16 January 2019 (has links)
<div> <div> <div> <p>Speech quality is a demand in voice commanded systems and in telephony. The voice communication system in real time often suffers from audible echoes. In order to cancel echoes, an acoustic echo cancellation system is designed and applied to increase speech quality both subjectively and objectively. </p> <p>In this research we develop various nonlinear adaptive filters wielding the new channel sparsity-aware recursive least squares (RLS) algorithms using a sequential update. The developed nonlinear adaptive filters using the sparse sequential RLS (S-SEQ-RLS) algorithm apply a discard function to disregard the coefficients which are not significant or close to zero in the weight vector for each channel in order to reduce the computational load and improve the algorithm convergence rate. The channel sparsity-aware algorithm is first derived for nonlinear system modeling or system identification, and then modified for application of echo cancellation. Simulation results demonstrate that by selecting a proper threshold value in the discard function, the proposed nonlinear adaptive filters using the RLS (S-SEQ-RLS) algorithm can achieve the similar performance as the nonlinear filters using the sequential RLS (SEQ-RLS) algorithm in which the channel weight vectors are sequentially updated. Furthermore, the proposed channel sparsity-aware RLS algorithms require a lower computational load in comparison with the non-sequential and non-sparsity algorithms. The computational load for the sparse algorithms can further be reduced by using data-selective strategies. </p> </div> </div> </div>
227

Algoritmos adaptativos LMS normalizados proporcionais: proposta de novos algoritmos para identificação de plantas esparsas / Proportional normalized LMS adaptive algorithms: proposed new algorithms for identification of sparse plants

Castelo Branco, César Augusto Santana 12 December 2016 (has links)
Submitted by Rosivalda Pereira (mrs.pereira@ufma.br) on 2017-06-23T20:42:44Z No. of bitstreams: 1 CesarCasteloBranco.pdf: 11257769 bytes, checksum: 911c33f2f0ba5c1c0948888e713724f6 (MD5) / Made available in DSpace on 2017-06-23T20:42:44Z (GMT). No. of bitstreams: 1 CesarCasteloBranco.pdf: 11257769 bytes, checksum: 911c33f2f0ba5c1c0948888e713724f6 (MD5) Previous issue date: 2016-12-12 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPQ) / This work proposes new methodologies to optimize the choice of the parameters of the proportionate normalized least-mean-square (PNLMS) adaptive algorithms. The proposed approaches use procedures based on two optimization methods, namely, the golden section and tabu search methods. Such procedures are applied to determine the optimal parameters in each iteration of the adaptation process of the PNLMS and improved PNLMS (IPNLMS) algorithms. The objective function for the proposed procedures is based on the a posteriori estimation error. Performance studies carried out to evaluate the impact of the PNLMS and IPNLMS parameters in the behavior of these algorithms shows that, with the aid of optimization techniques to choose properly such parameters, the performance of these algorithms may be improved in terms of convergence speed for the identification of plants with high sparseness degree. The main goal of the proposed methodologies is to improve the distribution of the adaptation energy between the coefficients of the PNLMS and IPNLMS algorithms, using parameter values that lead to the minimal estimation error of each iteration of the adaptation process. Numerical tests performed (considering various scenarios in which the plant impulse response is sparse) show that the proposed methodologies achieve convergence speeds faster than the PNLMS and IPNLMS algorithms, and other algorithms of the PNLMS class, such as the sparseness controlled IPNLMS (SC-IPNLMS) algorithm. / Neste trabalho, novas metodologias para otimizar a escolha dos parâmetros dos algoritmos adaptativos LMS normalizados proporcionais (PNLMS) são propostas. As abordagens propostas usam procedimentos baseados em dois métodos de otimização, a saber, os métodos da razão áurea e da busca tabu. Tais procedimentos são empregados para determinar os parâmetros ótimos em cada iteração do processo de adaptação dos algoritmos PNLMS e PNLMS melhorado (IPNLMS). A função objetivo adotada pelos procedimentos propostos é baseada no erro de estimação a posteriori. O estudo de desempenho realizado para avaliar o impacto dos parâmetros dos algoritmos PNLMS e IPNLMS no comportamento dos mesmos mostram que, com o auxílio de técnicas de otimização para escolher adequadamente tais parâmetros, o desempenho destes algoritmos pode ser melhorado, em termos de velocidade de convergência, para a identificação de plantas com elevado grau de esparsidade. O principal objetivo das metodologias propostas é melhorar a distribuição da energia de ativação entre os coeficientes dos algoritmos PNLMS e IPNLMS, usando valores de parâmetros que levam ao erro de estimação mínimo em cada iteração do processo de adaptação. Testes numéricos realizados (considerando diversos cenários nos quais a resposta impulsiva da planta é esparsa) mostram que as metodologias propostas alcançam velocidades de convergência superiores às dos algoritmos PNLMS e IPNLMS, além de outros algoritmos da classe PNLMS, tais como o algoritmo IPNLMS com controle de esparsidade (SCIPNLMS).
228

Adaptive PN Code Acquisition Using Smart Antennas with Adaptive Threshold Scheme for DS-CDMA Systems

Lin, Yi-kai 27 August 2007 (has links)
In general, PN code synchronization consists of two steps: PN code acquisition (coarse alignment) and PN code tracking (fine alignment), to estimate the delay offset between received and locally generated codes. Recently, the schemes with a joint adaptive process of PN code acquisition and the weight coefficients of smart antenna have been proposed for improving the received signal-to-interference-plus-noise ratio (SINR) and simultaneously achieving better mean-acquisition-time (MAT) performance in direct-sequence code-division multiple access (DS-CDMA) systems. In which, the setting of the threshold plays an important role on the MAT performance. Often, the received SINR is varying, using the fixed threshold acquisition algorithms may result in undesirable performance. To improve the above problem, in this thesis, a new adaptive threshold scheme is devised in a joint adaptive code acquisition and beam-forming DS-CDMA receiver for code acquisition under a fading multipath and additive white Gaussian-noise (AWGN) channels. The basic idea of this new adaptive threshold scheme is to estimate the averaged output power of smart antenna to scale a reference threshold for each observation interval, such that it can approximately achieve a constant false alarm rate (CFAR) criteria. The system probabilities of the proposed scheme are derived for evaluating MAT under a slowly fading two-paths channels. Numerical analyses and simulation results demonstrate that the proposed adaptive threshold scheme does achieve better performance, in terms of the output SINR, the detection probability and the MAT, compared to a fixed threshold method.
229

Learning Management Systems as a Tool for Community-based Project Management

Mohamed, Bahaaeldin, Köhler, Thomas 15 May 2014 (has links) (PDF)
This paper addresses a new conceptual framework for a communitybased project management learning model that aims to support learning within a project and enhance the distribution of knowledge within a particular virtual community. This model also aims to develop a virtual community of doctoral students, who can manage their own projects online with other community members who have the same interest. In order to develop that model, a checklist of community-based project management process has been developed in the light of the literature review and the needs of stakeholders (doctoral students and researchers). Within this model, community-based project management includes three main elements: community, project and management. In relation to project, there are two main sub elements. First is projectbased learning (PBL), which is based on constructivist perspective of learning that make students construct their knowledge when they work together to accomplish specific goals. Second is the project management body of knowledge (PMBOK), which is a project management guide, and an internationally recognized standard [PMBOK Guide, 2004], that provides the fundamentals of project management as they apply to a wide range of projects, including construction, software, engineering, automotive, so the study deploy this approach to scaffold based project management learning model. In the terms of the community element, this study adopted the community of inquiry model, which defines a good e-learning environment through three major aspects: cognitive presence, social presence and teaching presence. The last element which is addressed in this study called knowledge management. After identifying these elements, this study investigates a range of tools in the light of this model. The study analyses six different learning and content management systems (OPAL, Moodle, Joomla, e107, ZMS and TUDWCMS) in order to find out tool(s) that is/are sufficient for implementing the suggested study model.
230

The Impact of Learning Management System Usage on Cognitive and Affective Performance

Mabed, Metwaly, Köhler, Thomas 14 December 2012 (has links) (PDF)
1 INTRODUCTION Since learning management systems (LMSs) are offering a great variety of channels and workspaces to facilitate information sharing and communication among learners during learning process, many educational organizations have adopted a specific LMS into their educational context. A LMS is a software that handles learning tasks such as creating course catalogs, registering students, providing access to course components, tracking students within courses, recording data about students, and providing reports about usage and outcomes to teachers [1]. LMSs include several applications such as OLAT, WebCT, Moodle, ATutor, Ilias, and Claroline. However, LMSs can be utilized to integrate a wide range of multimedia materials, blogs, forums, quizzes, and wikis. Therefore, the researchers suggest that studying the influence of technology usage on end-users, especially students, is fundamental in learning and teaching environment. Despite educational organizations routinely make decisions regarding the best pedagogical approaches for supporting students’ performance, there is very little research on the impact of LMSs on learning outcomes [2]. Indeed, a considerable number of studies were conducted to examine the adoption of various LMSs, whereas little researches focused on understanding how educational institutes can enhance learning and teaching process through a particular LMS [3]. Consistent with this, the researchers found virtually no research on investigating the relationship between LMSs usage and attitude toward learning. [...]

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