18,762 research outputs found
Using performance assessment in secondary school mathematics: an empirical study in a Singapore classroom
No full textThis article reports an exploratory study on using performance assessment in mathematics instruction in a high-performing secondary school in Singapore. An intact mathematics class participated in the study, and received chapter-based performance tasks as intervention during regular mathematics lessons for about one and a half school years. The performance tasks used included authentic and/or open-ended tasks. The students’ academic achievements and attitudes in mathematics were compared with a comparison class that did not receive the intervention. Both quantitative and qualitative data were collected, mainly through questionnaire surveys, performance task tests, conventional school exams, and interviews with students and teachers. The results suggest that the students receiving the intervention performed significantly better than their counterparts in solving conventional exam problems, and in general they also showed more positive changes in attitudes towards mathematics and mathematics learning. The students from the experimental class also expressed positive views about the benefits of using performance tasks in promoting their ability in higher order thinking, though no statistically significant difference was detected between the two classes of students in solving unconventional tasks before and after intervention. Overall, the results appear to support teachers’ using contextualised problems in real life situations and open-ended investigations in students’ learning of mathematic
Richardson, Barbauld, and the construction of an early modern fan club
No full textMPhilMuch has been written about the life and long works of the eighteenth century epistolary novelist, Samuel Richardson, but the prospect of his position as the first celebrity novelist – responsible for courting his own fame as well as initiating his own fan club – has largely been ignored. The body of manuscripts housed at the National Art Library in the Victoria and Albert Museum in London provides the modern scholar with evidence of the skeletal beginnings of an early fan club. This thesis aims to show how these manuscripts were turned into a saleable commodity by the publisher and entrepreneur Richard Phillips, while under the guiding hand of another, slightly later, literary celebrity, Anna Laetitia Barbauld. In order to restore Richardson’s reputation amongst a new nineteenth century audience, Barbauld was required to construct her own idea of him as an eighteenth century celebrity author, and in doing so the insecurities of a self-professed, apparently diffident man, are revealed. Barbauld’s capacious, but heavily edited selection of letters is analyzed in this thesis, providing ample evidence that Richardson’s correspondents were more than just eager letter writers. By using Barbauld’s biography of Richardson this thesis aims to show how she manipulates the genre of life writing in her construction of him.
This thesis offers an alternative reading of how the Richardson manuscripts are viewed, redefining them as not simply a collection of letters, but as a collective entity, deliberately selected and archived as evidence of an early modern fan club, and its celebrity managing director
FAN 2002: um modelo neuro-fuzzy para reconhecimento de padrões
No full textTese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia de Produção.Nesta tese é apresentado FAN 2002 - free associtive neurons - como uma abordagem neuro-fuzzy para reconhecimento supervisionado de padrões. Aspectos foram modificados desde a sua publicação inicial, em 1997: a criação de células para a combinação de características é substituida pela inclusão de uma característica extra que representa a combinação das demais; a forma de realizar a penalização em caso de erro é modificada; a inicialização dos neurônios é realizada com valores aleatórios; um hedge é usado no teste de um padrão. Os resultados em aplicações são mostrados: no problema de classificação de cromossomos, a comparação com os resultados o obtidos por outros métodos apresentados ilustra o desenvolvimento do modelo desde as suas primeiras implementações; A aplicação do modelo em jogos de empresas na construção de um agente; Os conceitos de FAN na construção dos Mapas FAN e a solução do problema do XOR. A apresentação de FAN 2002 visa proporcionar aos interessados na aplicação de soluções em reconhecimento de padrões uma ferramenta útil e de uso geral.A conclusão do trabalho mostra o resumo dos avanços obtidos no desenvolvimento de FAN e aponta para o futuro do método uma possibilidade interdisciplinar de subsidiar pesquisadores de outras áreas a resolverem os seus próprios problemas de classificação e reconhecimento
Development of a rotor model for the numerical simulation of helicopter exterior flow-fields
No full textIncludes bibliographical references (leaves 84-85).A numerical methodology is developed to model the effect of a rotor on the surrounding flow-field. The model calculates the time-averaged aerodynamic forces exerted on the air by the fan blades within the blade-swept region, and permits the user to specify blade properties such as cross-sectional profile and orientation at a particular radial and azimuthal location. The calculated forces are included as source terms within the Reynolds-averaged Navier-Stokes equations for an incompressible fluid, which are solved by the commercial CFD solver, FLUENT. The effects of turbulence are incorporated through the use of Launder and Spalding's k-g turbulence model. This method is selected as being the most efficient use of the resources available, giving the economic advantages of a steady simulation, while allowing radial and azimuthal variations of rotor characteristics. In order to validate the accuracy of the numerical model for both aligned and non-aligned inflow conditions, results are compared with experimental data reported for an axial flow fan. Agreement between experimental and numerical results is excellent to good. Fan static pressure rise is closely predicted by the numerical solution, while fan power consumption and fan static efficiency are under and over-predicted respectively. This error may be attributed to frictional losses not accounted for in the numerical model. These include physical rotational instabilities, leading to increased mechanical losses, and tip effects due to the clearance between the fan blade tips and the fan casing. Trends are nevertheless consistently predicted by the numerical model for inflow angles up to 45°, and for the range of blade pitch settings used. The adverse effect of off-axis inflow on the fan static pressure rise is numerically predicted, while fan power consumption is found to remain independent of inflow angle, as had been experimentally observed. The rotor model is finally integrated with the fuselage of the CIRSTEL (Combined Infra-Red Suppression and Tail rotor Elimination) prototype in an analysis of the helicopter exterior flow-field. No experimental data for this configuration was available for validation purposes. However, the model is used in the simulation of several common helicopter flight conditions. Results are presented graphically, and generally indicate good agreement with physically observed phenomena
Aeroacoustics Analysis of Radiator Installation Effects in a Pulling Engine Cooling Module
No full textFan noise is a critical issue for manufacturers, as they must balance aerodynamic and acoustic performance. Coupling a fan with a radiator in a pulling configuration, introduces significant challenges. Since it is challenging to perform scale resolved simulations of a radiator, an equivalent fluid approach is adopted. This study investigates the effects of an equivalent porous medium mimicking the radiator, and casing geometry on inflow and noise sources in an industrial cooling fan. Three configurations (Fan + Frame + Equivalent Porous Medium, Fan + Frame, Fan) are investigated using high-fidelity simulations. While aerodynamic performance remains consistent, the equivalent porous medium and casing geometry introduce inflow distortions, causing tonal noise variations, particularly in the full module configuration
Mapa fan no estagiamento automático do sono
No full textTese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico.Este trabalho apresenta um novo método para a classificação automática dos estágios do sono utilizando um canal do eletroencefalograma (C3). O sistema de classificação consiste de três módulos: o pré-processamento com extração de características, o classificador Mapa FAN, e um pós-processamento. A extração de característica consiste na ordenação e na redução de dimensão do sinal digital em cada época. O Mapa FAN é um sistema de classificação baseado na tecnologia de redes neurais artificiais, onde cada classe de padrões é representada por um mapa (matriz bidimensional). Para todo o padrão de entrada, cada mapa gera o grau de ativação daquele padrão em relação à classe que o mapa representa. Os Mapas foram treinados com os dados de um paciente e testados em outros sete pacientes, usando épocas de 30 segundos. Após a classificação feita pelo Mapa FAN, um sistema de regras de inferência, baseadas em estudos sobre a evolução do sono durante a noite, é aplicado para corrigir algumas falhas da classificação. Os resultados da classificação comparados com os de um especialista humano alcançaram uma concordância de 60 a 80%. Esses resultados estão dentro dos limites encontrados por outros pesquisadores, o que comprova a eficácia do modelo. Portando, o sistema Mapa FAN pode ser utilizado neste e em outros problemas de reconhecimento de padrões que apresentam multidimensionalidade
Numerical analysis of the arc in pulsed current gas tungsten arc welding using a boundary-fitted coordinate
No full textA two-dimensional transient model is introduced to describe the heat transfer and fluid flow in pulsed current gas tungsten welding are (GTA). In the model, a boundary fitted coordinate system is adopted to describe precisely the cathode shape. The current-continuity equation has been solved with the combined are plasma-cathode system, independent of the assumption of the current density distribution on the cathode surface, which was essential in previous studies of the are plasma. The temperature distribution in pulsed GTA welding has been described and the transition processes of temperature contours and are pressures at the anode center have been studied. Moreover, the effects of pulsed welding parameters on the dynamic processes of the are pressure at the anode center have been studied using the developed model, the results being compared with experimental data measured by the micro-pressure sensor. (C) 1997 Elsevier Science S.A
Heat transfer and fluid flow in a partially or fully penetrated weld pool in gas tungsten arc welding
No full textIn this study, fluid flow driven by a combination of electromagnetic force, buoyancy force, are drag force, and surface tension gradient is numerically analyzed for a partially or fully penetrated weld pool in stationary gas tungsten are welding (GTAW). Irregular shape of the weld pool and the moving liquid-solid interface is handled by a boundary-fitted-coordinates technique. Surface tension on the top and the bottom free surfaces of the weld pool is found to play a critical role in determining the flow pattern in the weld pool. The calculated GTA weld bead geometry compares favorably with experimental results. (C) 2000 Elsevier Science Ltd. All rights reserved.This work was supported by the U.S. Army Research Office under grant number DAAH-95-1-0136 which is gratefully acknowledged
How Is Educational Gamification Represented in School Curriculum? An Investigation of Chinese Secondary Mathematics Textbooks
No full textTextbooks, as potentially implemented curriculum, play an important role in school education. Earlier studies in mathematics education revealed that teaching using mathematics games had a positive effect on students’ learning. However, how mathematics games are presented in mathematics textbooks has rarely been systematically examined. In this study, we aimed to investigate how mathematics games are presented in school mathematics textbooks in China. We selected three series of Chinese secondary mathematics textbooks (Grades 7–9) and identified 112 mathematics games in total; then, we coded and analyzed the games according to an analysis framework we established for the study. The results showed that, across the three series of textbooks, the distribution of games was inconsistent and, within the same series of textbooks, it was irregular across the different grade levels; in terms of locations and cognitive objectives, most games were presented as exercise questions and the main purpose was to improve students’ problem solving ability. Moreover, most of the games were single player games and there were slightly more competitive games than non-competitive games. The implications of the findings for the design and research of mathematics games in mathematics textbooks are discussed at the end of the study
Fan Fiction and Copyright: Outsider Works and Intellectual Property Protection
No full textAs long as there have been fans, there has been fan fiction. There seems to be a fundamental human need to tell additional stories about the characters after the book, series, play or movie is over. But developments in information technology and copyright law have put these fan stories at risk of collision with the content owners’ intellectual property rights. Fan fiction has long been a nearly invisible form of outsider art, but over the past decade it has grown exponentially in volume and in legal importance. Because of its nature, authorship, and underground status, fan fiction stands at an intersection of key issues regarding property, sexuality, and gender. In Fan Fiction and Copyright, author Aaron Schwabach examines various types of fan-created content and asks whether and to what extent they are protected from liability for copyright infringement. Professor Schwabach discusses examples of original and fan works from a wide range of media, genres, and cultures. From Sherlock Holmes to Harry Potter, fictional characters, their authors, and their fans are sympathetically yet realistically assessed. Fan Fiction and Copyright looks closely at examples of three categories of disputes between authors and their fans: Disputes over the fans’ use of copyrighted characters, disputes over online publication of fiction resembling copyright work, and in the case of J.K. Rowling and a fansite webmaster, a dispute over the compiling of a reference work detailing an author's fictional universe. Offering more thorough coverage of many such controversies than has ever been available elsewhere, and discussing fan works from the United States, Brazil, China, India, Russia, and elsewhere, Fan Fiction and Copyright advances the understanding of fan fiction as transformative use and points the way toward a safe harbor\u9d for fan fiction
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