• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 68
  • 38
  • 23
  • 13
  • 11
  • 5
  • 3
  • 3
  • 3
  • 3
  • 3
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 162
  • 60
  • 39
  • 38
  • 35
  • 35
  • 33
  • 31
  • 30
  • 25
  • 25
  • 24
  • 23
  • 21
  • 20
  • 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.
71

Transformação de frações em números: uma experiência no Ensino Fundamental / The transformation of fractions into numbers: an experience in Basic Education

Ananias, Izabela Cesario Correa 27 February 2019 (has links)
Este estudo se insere na problemática do ensino e aprendizagem de frações no Ensino Fundamental e, mais particularmente, no que se refere à apreensão das frações como números pelos alunos. Essa concepção da fração como número é descrita na literatura da área de Educação Matemática como problemática para os alunos, pois, em geral, concebem a representação a/b (com a e b naturais e b não nulo) apenas como um duplo processo de contagem no modelo parte-todo. Decidiu-se, portanto, investigar o impacto de algumas abordagens que ampliassem a referida concepção de fração como parte de inteiro. Para tanto, tomou-se como base algumas pesquisas que destacam diferentes ideias e situações para conceituar frações, bem como a Teoria dos Registros de Representação Semiótica de Raymond Duval, devido à importância de se abordar as frações em seus vários significados, por meio de diferentes representações. Realizou-se um estudo experimental de caráter qualitativo, inspirado na metodologia de Design Experiment, envolvendo 24 alunos do 6º ano do Ensino Fundamental de uma escola em Goiânia. A elaboração das atividades fundamentou-se nos constructos teóricos do levantamento bibliográfico, bem como em um questionário inicial que permitiu identificar as principais dificuldades do grupo de alunos. As hipóteses consideradas no design foram: ênfase em atividades de conversão de representações entre os registros numérico ou figural e o gráfico (reta numérica), em ambos os sentidos; e foco na ideia da fração como representação do resultado de uma divisão de dois números naturais. Foram realizadas quatro atividades, com diversas tarefas em cada uma delas, ao longo de nove encontros no âmbito das aulas regulares de Matemática. As propostas transitaram entre trabalhos em grupo e individuais, envolvendo recursos tradicionais e materiais concretos, sendo que a coleta de dados deu-se essencialmente a partir das observações da pesquisadora e dos registros orais e escritos das produções dos alunos. Na atividade principal, foi introduzido um recurso para realizar a divisão de segmentos em partes congruentes, visando dar condição para os alunos representarem frações não decimais em retas numéricas, sem realizar a conversão para a representação decimal e/ou efetuar aproximações imprecisas. As análises mostraram que houve, em geral, um amadurecimento dos estudantes em relação às ideias apresentadas, aproximando-os da concepção de fração como número uma vez que explicitaram compreensão de aspectos de equivalência e ordem ao posicionar frações em retas numéricas e perceberam que tais frações correspondiam a resultados de divisões entre dois números naturais, isto é, a quocientes vistos como quantidades. / This study concerns the issue of teaching and learning fractions in Basic Education and, more particularly, regards the students apprehension of fractions as numbers. The notion of fractions as numbers is described in Mathematics Education literature as problematic for students, since, generally, they understand the representation a/b (where a and b are natural numbers and b is different than zero) only as a double counting process in the part-whole model. Therefore, we decided to investigate the impact of some approaches that broadened the notion of fraction as part of a whole. In order to achieve that, we used as a basis research that highlights different ideas and situations to conceptualize fractions, as well as Raymond Duvals Theory of Registers of Semiotic Representation, due to the importance of approaching fractions in their diverse meanings, through different representations. We carried out an experimental study of qualitative character, inspired by the Design Experiment methodology, with 24 students in the 6th grade from a school in Goiânia. The activities were written based on the theoretical constructs analyzed in the bibliographic search, as well as based on an initial questionnaire that allowed us to identify the main difficulties that the student group had. The hypotheses considered in the design were: emphasis on activities concerning representation conversion between numerical or figural registers and graphical (number line) in both directions; and focus on the idea of fraction as the representation of a division of two natural numbers. Four activities were carried out, with several tasks in each one, along nine meetings in the context of regular Math classes. The activities varied between group and individual tasks, involving traditional resources and concrete materials, with the data collection taking place essentially through the researchers observations and oral and written records of the students productions. In the main activity, we introduced a resource to facilitate the division of segments into congruent parts, aiming to help the students depict non-decimal fractions in number lines without converting them into the decimal register and/or using inaccurate approximations. The analysis shows that, generally, there was an improvement in the students concerning the ideas presented in the activities, bringing them closer to the concept of fractions as numbers, as they demonstrated understanding aspects of equivalence and order by placing fractions in number lines and realized that these fractions corresponded to the results of divisions of two natural numbers, that is, quotients perceived as quantities.
72

Dewey i Sverige : En diskursanalys av den svenska bibliotekssektorns uttalanden om klassifikationssystemet DDK / Dewey in Sweden : A discourse analysis of the Swedish library sector’s statements about the classification system DDC

Rosberg, Sara January 2012 (has links)
Swedish libraries are currently discussing andimplementing the classification system Dewey (DDC).Most libraries in Sweden have used the Swedishclassification system SAB until recently. In 2008 TheRoyal Library of Sweden (KB) decided to switch fromSAB to DDC. Many academic libraries chose to followKB’s example and by January 2011 a switch was made atKB and at many academic libraries.The aim of this master thesis is to examine and analysethe library sector’s discussion that occurred before andduring the Swedish switch from SAB to DDC. The mainquestion asked is; What is being discussed about Dewey2010-2011 and in what manner? To organize and anlysethis discussion discourse analysis is used. Discourseanalysis by Laclau and Mouffe is used both as methodand theoretic ground. The material which has beenanalyzed consists of the library sector’s discussions andstatements found in journals, reports, blogs, meetingprotocols and seminar.The analysis shows four different discourses; thetransition discourse, the spatial discourse, the instrumentaldiscourse and the public library discourse. In conclusion,it can be argued that the transfer to Dewey has gone froma planning stage to an implementing stage at academiclibraries. Public libraries in Sweden have shown lessinterest and are considered to be in a planning stageparallel to the academic libraries implementing stage.Earlier discussions about pros and cons with Dewey havealmost disappeared 2010-2011 and discussions of spatialmatters are frequently occurring in the material. / Program: Bibliotekarie
73

3D reconstruction of specular micro-surfaces in typical electronic manufacturing. / CUHK electronic theses & dissertations collection

January 2006 (has links)
As the electronic industry advances rapidly, the dimensions of the semiconductor products keep on being shrunk and that leads to more stringent requirement on process control and quality assurance. In particular, area array packages like BGA, CSP, flip chips, wafer bumping and wafer-level packaging need to have the 3D quality of some micro-surfaces inspected accurately and efficiently. An example of the micro-surfaces is the solder bumps for direct die-to-die bonding, which are of size as small as 60 to 600 microns in diameter. However, the tiny size and often highly specular and textureless nature of the surfaces make the inspection difficult. In addition, the size of the inspection system is required to be small so as to minimize restraint, on the operation of the various moving parts involved in the manufacturing process. / Experimental results with image data of a variety of objects have positively demonstrated the feasibility of the proposed methodology. / In the mechanism the inspection speed is governed by the number of needed images which also equals the number of spatial shiftings of the grating. This thesis also addresses how the grating, as well as its spatial shifting, can be designed optimally for minimizing this image number for faster inspection speed. An optimal solution to shifting strategy optimization is proposed that is applicable to any pattern on the fringe grating. A design method is also introduced for optimal pattern design, which has higher efficiency than brute-force searching. To reduce image number furthermore, bit-pairing codification mechanism and color-encoded pattern are proposed and verified to be more efficient. / In this thesis, I propose a new methodology for reconstructing micro-surfaces in 3D. The mechanism is based upon the familiar concept of binary structured-light, projection, but adapted, for the purpose of greatly reducing the system size, from the traditional setup of an array of multiple light sources to one with a single light source. The mechanism consists of a single light source in combination with a binary grating for projecting a binary pattern onto the target surface, and of a camera for capturing image of the illuminated scene. By shifting the binary grating in space and in every drifting taking a separate image of the illuminated surface, each position on the illuminated surface will be attached with a string of binary code over the sequence of captured images. With a suitable design of the binary grating, the binary code string can be made unique for each bump surface position, allowing exact correspondence between the binary pattern and image data, and subsequently 3D determination through triangulation. With such a bright-or-dark world for each image position, the issues of image saturation, image noise, and textureless nature of the target surfaces are avoided. / Jun Cheng. / "June 2006." / Adviser: Ronald Chi-kit Chung. / Source: Dissertation Abstracts International, Volume: 67-11, Section: B, page: 6499. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 107-117). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.
74

Is it all in their heads? : A study of the strategies used in mental arithmetic by Swedish pupils in their last years of the obligatory school and in the upper secondary school

Björkström, Angela January 2008 (has links)
<p>Competence in mental arithmetic is recognised by many as essential to be active participants in the fast flowing, high technological society we live in today.  Many have noticed pupils’ unwillingness to set their calculators aside and practice this aspect of mathematics when possible.  Furthermore, some studies show that pupils’ ability to compute mentally deteriorates as they pass through the school system.  Through testing classes in a Swedish obligatory school and an upper secondary school, the aim of this thesis is to see if the goals set by The National [Swedish] Agency for Education regarding mental arithmetic, are being fulfilled.  Through using questionnaires to collect the strategies and ideas of the pupils, a wide range of problematic mathematical misconceptions became evident.  These are highlighted since they are important aspects teachers should be aware of.  The results of this study show that the obligatory school classes are far from reaching the goals set for them whereas the upper secondary classes show good results.  Furthermore, there is an apparent improvement in their progression, resulting in a fulfilment the official goals.  Many pupils however, seem reluctant to rely on their mental arithmetic capabilities and resort to algorithmic strategies.  Other problems to emerge are in carrying out table calculations and in a lack of number sense when deeming if the answers are reasonable.   </p>
75

Algebraic decoding for a binary erasure channel

January 1958 (has links)
M.A. Epstein. / "March 14, 1958"--Cover. "Reprinted from the 1958 IRE National Convention Record, Part 4"--P. 69. / Bibliography: p. 66. / Army Signal Corps Contract DA36-039-sc-64637. Dept. of the Army Task 3-99-06-108 and Project 3-99-00-100.
76

Is it all in their heads? : A study of the strategies used in mental arithmetic by Swedish pupils in their last years of the obligatory school and in the upper secondary school

Björkström, Angela January 2008 (has links)
Competence in mental arithmetic is recognised by many as essential to be active participants in the fast flowing, high technological society we live in today.  Many have noticed pupils’ unwillingness to set their calculators aside and practice this aspect of mathematics when possible.  Furthermore, some studies show that pupils’ ability to compute mentally deteriorates as they pass through the school system.  Through testing classes in a Swedish obligatory school and an upper secondary school, the aim of this thesis is to see if the goals set by The National [Swedish] Agency for Education regarding mental arithmetic, are being fulfilled.  Through using questionnaires to collect the strategies and ideas of the pupils, a wide range of problematic mathematical misconceptions became evident.  These are highlighted since they are important aspects teachers should be aware of.  The results of this study show that the obligatory school classes are far from reaching the goals set for them whereas the upper secondary classes show good results.  Furthermore, there is an apparent improvement in their progression, resulting in a fulfilment the official goals.  Many pupils however, seem reluctant to rely on their mental arithmetic capabilities and resort to algorithmic strategies.  Other problems to emerge are in carrying out table calculations and in a lack of number sense when deeming if the answers are reasonable.
77

Man måste ställa upp : Hylluppställning på svenska högskole- och specialbibliotek som klassificerar i DDC / Shelving Dewey : Shelving strategies among Swedish university and special libraries using the DDC

Ehn, Einar Gustav January 2012 (has links)
The aim of this master's thesis is to examine how shelving is organized among Swedish libraries that have switched from the Swedish classification system SAB to using the DDC, and what problems arise in this process. The method used is interviewing librarians at Swedish university and special libraries. The Swedish national library announced their swap to the DDC in 2008, and several libraries followed suit. The reported advantages with a switch were mainly that using an international classification system meant that Swedish libraries would no longer have to undertake a time consuming classification work, since most of the foreign literature already is Dewey classified. Disadvantages were that the DDC is not adapted to Swedish circumstances. Research on open shelving show that obtaining a browsable book collection requires a broad shelf classification. If libraries motivate their shelving solution by wanting browsable collections, efforts will be made to keep shelf classification broad enough. Certain categories have by tradition been shelved separately in Swedish libraries, and this study seeks to find out if a classification shift changes this custom, and if so, whether or not this is only attributable to the change of classification. Findings show that libraries motivated their swapping of classification mostly by the perceived flaws of the SAB system, and not by the promise of saving time, nor by the benefits of the DDC system. Most librarians seemed to lack sufficient knowledge of the DDC, which may be a reason why librarians claimed that the workload necessary to re-shelve the stock was the biggest drawback with switching to the DDC. Most libraries desired browsable shelves, and therefore used shelf lists to better be able to adapt the classification system to the stock. The custom of shelving certain categories separately survived the classification swap for some categories, but not for others. In the latter case this can be ascribed to a dwindling use of these specific categories by the patrons.
78

Die Sacherschliessung an der ETH-Bibliothek Zürich

Pika, Jiri 30 June 2003 (has links) (PDF)
Abgerundet wurde die Thematik durch Berichte aus Bibliotheken, so der ETH-Bibliothek, Zürich. Jiri Pika berichtet von Nutzer-Anforderungen und den Versuchen der Bibliothekare, diese z.B. durch Einsatz von Klassifikation zu erfüllen.
79

DDC Deutsch – vom Projekt zur Dienstleistung

Heiner-Freiling, Magda 24 June 2005 (has links) (PDF)
Aus der Truppe der Beiträger, die überwiegend dezimalklassifikatorische Beiträge lieferten, gab Magda Heiner-Freiling, Die Deutsche Bibliothek, Frankfurt, einen Sachstandsbericht zum Projekt „DDC Deutsch“ und eine Vorausschau auf die zu erwartenden Dienstleistungen. Festzuhalten ist an dieser Stelle nur soviel, daß die Sachgruppen der Deutschen Nationalbibliografie seit Jahrgang 2004 auf DDC umgestellt sind; damit wurde unsere laufende Nationalbibliografie von einer hausgemachten Systematik in eine international gebräuchliche Klassifikation überführt. Dies entsprach auch der Empfehlung, die im Jahre 1998 von einer Expertenkommission des damaligen Deutschen Bibliotheksinstituts gegeben wurde, die überwiegend mit Mitgliedern der Gesellschaft für Klassifikation besetzt war. Mehr dazu findet sich unter www.ddc-deutsch.de
80

DDC Deutsch – vom Projekt zur Dienstleistung

Heiner-Freiling, Magda 21 August 2007 (has links) (PDF)
Das Original-Dokument wurde in das Format pdf umgewandelt. Aus der Truppe der Beiträger, die überwiegend dezimalklassifikatorische Beiträge lieferten, gab Magda Heiner-Freiling, Die Deutsche Bibliothek, Frankfurt, einen Sachstandsbericht zum Projekt „DDC Deutsch“ und eine Vorausschau auf die zu erwartenden Dienstleistungen. Festzuhalten ist an dieser Stelle nur soviel, daß die Sachgruppen der Deutschen Nationalbibliografie seit Jahrgang 2004 auf DDC umgestellt sind; damit wurde unsere laufende Nationalbibliografie von einer hausgemachten Systematik in eine international gebräuchliche Klassifikation überführt. Dies entsprach auch der Empfehlung, die im Jahre 1998 von einer Expertenkommission des damaligen Deutschen Bibliotheksinstituts gegeben wurde, die überwiegend mit Mitgliedern der Gesellschaft für Klassifikation besetzt war. Mehr dazu findet sich unter www.ddc-deutsch.de

Page generated in 0.0257 seconds