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Estimativa de medidas de tendência central: uma intervenção de ensinoLeite, Ana Paula Fernandes 25 May 2010 (has links)
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Previous issue date: 2010-05-25 / Secretaria da Educação do Estado de São Paulo / The objective of this study was to investigate the contributions of an educational
intervention, based on the significance and estimate measures of central tendency, from
reading charts and tables. In order to achieve this purpose, we elaborated a character
study of quasi-experimental design which included two distinct groups of a public school in
the state of São Paulo. The first group, called the experimental group(GE), composed of
30 students who underwent a differentiated education based on the significance and
estimate measures of central tendency, and the second group, called the control group
(GC), composed of 27 students who had their classes routine. Were applied to both
groups a pre-test to diagnose the level of prior knowledge of students involved, and a
post-test after the teaching interventions, to diagnose the effects of these interventions.
The theoretical framework of the study included the Theory of Conceptual Fields of
Gérard Vergnaud (1982, 1990, 1993, 1996, 1997 and 1998). We also have some related
studies by authors such as Batanero et al. (1997), Cazorla (2003), Echeveste et al.
(2006), Araujo (2007), Meyen et al. (2007), Silva (2008), Pagan (2009) and Magina et al.
(in press). The study aimed to answer the following question: "What contributions in terms
of learning, a teaching intervention guided the significance and estimate measures of
central tendency, brings high school students?". To this end, has become based on
quantitative analysis of the results obtained in the statistical tests applied to two groups
involved in the study. The analysis showed a significant gain with the teaching
interventions in both GE and CG, as regards the seizure of the basic concepts of mean,
mode and median, but a significantly higher performance was presented by students in
the experimental group after intervention education. The result showed that the learning
process of statistical content, guided by the significance and estimation proved to be
effective on the cognitive gain by students on information presented as graphs and tables,
and also how to gain strength in regarding knowledge of the statistical study, more
specifically, Mean, Mode and Median / O objetivo deste estudo foi investigar as contribuições de uma intervenção de
ensino, pautada na significação e estimativa de Medidas de Tendência Central, com base
na da leitura de gráficos e tabelas. A fim de atingir o objetivo proposto, elaborou-se um
estudo de caráter do tipo quase-experimental que contou com dois grupos distintos de
uma escola da rede pública estadual da cidade de São Paulo. O primeiro grupo,
denominado Grupo Experimental, composto por 30 alunos que sofreu uma intervenção
de ensino diferenciada, baseada na significação e estimativa de Medidas de Tendência
Central, e o segundo grupo, denominado Grupo de Controle, composto por 27 alunos,
que teve suas aulas rotineiras. Foram aplicados a ambos os grupos um pré-teste, a fim
de diagnosticar o nível de conhecimento prévio dos alunos envolvidos, e um pós-teste,
após as intervenções de ensino, visando a diagnosticar os efeitos dessas intervenções. O
quadro teórico do estudo contou com a Teoria dos Campos Conceituais de Gérard
Vergnaud (1982; 1990; 1993; 1996; 1997 e 1998). Contamos ainda com alguns estudos
correlatos de autores como Batanero et al. (1997), Cazorla (2003), Echeveste et al.
(2006), Araujo (2007), Meyén et al. (2007), Silva (2008), Pagan (2009) e Magina et al. (no
prelo). O estudo propôs-se a responder à seguinte questão: Em termos de
aprendizagem, quais as contribuições que uma intervenção de ensino pautada na
significação e estimativa de Medidas de Tendência Central traz aos alunos do
Ensino Médio? . Para tal, tomou-se por base a análise quantitativa dos resultados
obtidos nos testes estatísticos aplicados aos dois grupos envolvidos no estudo. As
análises apontaram um ganho significativo com as intervenções de ensino nos dois
grupos GE e GC, no que diz respeito à apreensão de conceitos básicos sobre Média,
Moda e Mediana, contudo um desempenho significativamente superior foi apresentado
pelos alunos do grupo experimental, após a intervenção de ensino. O resultado permitiu
inferir que o processo de aprendizagem de conteúdos de Estatística, pautado na
significação e estimativa, mostrou-se eficaz quanto ao ganho cognitivo por parte dos
alunos em informações apresentadas na forma de gráficos e tabelas, e, também, quanto
ao ganho adquirido no que diz respeito ao conhecimento dos elementos estatísticos
estudados, mais especificamente, Média, Moda e Mediana
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A Study of Four Statistics, Used in Analysis of Contingency Tables, in the Presence of Low Expected FrequenciesPost, Jane R. 01 May 1975 (has links)
Four statistics used for the analysis of categorical data were observed in the presence of many zero cell frequencies in two way classification contingency tables. The purpose of this study was to determine the effect of many zero cell frequencies upon the distribution properties of each of the four statistics studied. It was found that Light and Margolin's C and Pearson's Chi-square statistic closely approximated the Chi-square distribution as long as less than one-third of the table cells were empty. It was found that the mean and variance of Kullbach's 21 were larger than the expected values in the presence of few empty cells. The mean for 21 was found to become small in the presence of large numbers of empty cells. Ku's corrected 21 statistic was found, in the presence of many zero cell frequencies, to have a much larger mean value than would be expected in a Chi-square distribution. Kullback's 21 demonstrated a peculiar distribution change in the presence of large numbers of zero cell frequencies. 21 first enlarged, then decreased in average value.
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Investigation of Finite Groups Through ProgenitorsBaccari, Charles 01 December 2017 (has links)
The goal of this presentation is to find original symmetric presentations of finite groups. It is frequently the case, that progenitors factored by appropriate relations produce simple and even sporadic groups as homomorphic images. We have discovered two of the twenty-six sporadic simple groups namely, M12, J1 and the Lie type group Suz(8). In addition several linear and classical groups will also be presented. We will present several progenitors including: 2*12: 22 x (3 : 2), 2*11: PSL2(11), 2*5: (5 : 4) which have produced the homomorphic images: M12 : 2, Suz(8) x 2, and J1 x 2. We will give monomial progenitors whose homomorphic images are: 17*10 :m PGL2(9), 3*4:m Z2 ≀D4 , and 13*2:m (22 x 3) : 2 which produce the homomorphic images:132 : ((2 x 13) : (2 x 3)), 2 x S9, and (22)•PGL4(3). Once we have a presentation of a group we can verify the group's existence through double coset enumeration. We will give proofs of isomorphism types of the presented images: S3 x PGL2(7) x S5, 28:A5, and 2•U4(2):2.
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Analysis of Contingency TablesBiundo, James Joseph 01 May 1969 (has links)
Two methods of analyzing multi-dimensional frequency data are detailed.
The Second Order Exponential (SOE) model is applicable for dichotomous classifications. The distribution has two sets of parameters, ϴi's and ϴj's. The ϴi's are interpreted as the log of the odds of the marginal probabilities if no two factor relationships exist. Or if all ϴij are not zero, then the ϴi's are analogous to a main effect in a 2m factorial analysis, (m = number of factors or classifications). The ϴif's may be interpreted as a measure and direction of the two factor relationships. These ϴij are analogous to partial or adjusted phi-coefficients.
The second method discussed assumes a multinomial distribution and the statistics are developed from an Information Theoretic Approach. Each hypothesis is tested using twice the minimum discrimination information statistic (m.d.i.s), 2I. From the null hypothesis it is possible to estimate unique cell probabilities by an iterative metod. Then 2 is equal to 2 (sample frequencies) log (sample frequencies) - 2 (expected frequencies) log (expected frequencies). (141 pages)
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An Exploration of the Relationship between Institutional Financial Resources and Global RankingAnderson, Matthew S. 14 March 2018 (has links)
Global rankings are a popular way for governments, HEI’s, faculty, staff, and students to compare institutions worldwide, therefore it is important to rank well. However, in order to have top-quality research and education programs, HEI’s need to have significant financial resources. The purpose of this study was to explore the relationship between an institution’s financial resources and its global ranking. The results of this study provide additional insight and a better understanding of global rankings and the nature of the relationship between various financial resources and global rankings.
This was a quantitative study that used ranking data from the Academic Ranking of World Universities (ARWU) and Times Higher Education (THE) World University Rankings, as well as financial data from IPEDS. Descriptive statistics were presented to develop an awareness of the data set characteristics. Linear regression and the Pearson Product-Moment Correlation Coefficient (PPMCC) were reported to gauge the strength of the relationship between the financial resource independent variables and the global ranking dependent variables.
This study indicated there was a strong relationship between an institution’s financial resources and its global ranking as there was a strong positive correlation between total revenue and an institution’s global ranking. In addition, the study showed that institutions should continue to self-generate financial resources, such as tuition revenue and research funding. This is especially true for research funding as it had the strongest relationship with ranking, which means institutions would be wise to continue focusing on investing in their research programs. This study also showed that some financial variables such as endowment size and state appropriation only had weak to moderate relationships with the global rankings.
Based on this study, one could conclude then that global rankings are influenced by money, which supports the claims of critics that university rankings are biased. Thus, institutions will continue to be challenged to find some balance between investing in what global rankings measure while also maintaining other initiatives that address their core missions but are not counted in the rankings.
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TEAMViz : systèmes multi-dispositifs, multi-vues et multi-surfaces pour la visualisation interactive de scènes 3DAjaj, Rami 16 November 2009 (has links) (PDF)
Les environnements virtuels sont des espaces immersifs et intuitifs mais la conception des interfaces d'édition et de navigation y est complexe en raison de la diversité des dispositifs d'interaction et des tâches à réaliser. Les tables tactiles offrent des interactions intuitives mais proposent seulement un nombre limité de degrés de liberté. Dans le but de mieux couvrir les besoins d'interaction dans les environnements 3D, nous proposons la conception des TEAMViz (Tabletop Environment Augmented with Mural Visualization soit en français environnement tabletop augmenté par une visualisation murale). Les TEAMViz combinent des interactions réalisées au moyen d'une vue 2D d'un environnement virtuel présentée sur une table tactile et des interactions au moyen d'une vue 3D en perspective de ce même environnement projetée sur un écran vertical. La contribution principale de notre recherche est la réalisation d'une méthode de conception pour la combinaison d'interactions effectuées avec plusieurs dispositifs d'entrée sur des vues multiples présentées sur des surfaces d'affichage distinctes pour des tâches d'édition et de navigation dans un environnement virtuel. Cette méthode de conception prend en compte les relations entre les degrés de liberté des dispositifs d'entrée dans le monde réel, les tâches à réaliser et les relations entre les vues. Elle permet de combiner des interactions réalisées avec des dispositifs dont le couplage fort entre l'entrée et la sortie est requis comme dans le cas des surfaces tactiles.
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Properties and tables of the extended Airy-Hardy integralsJanuary 1951 (has links)
M.V. Cerrillo, W.H. Kautz. / "November 15, 1951." / Bibliography: p. 11. / Army Signal Corps Contract DA36-039 SC-64637 Project 102B. Dept. of the Army Projects 3-99-10-022 and DA3-99-10-000.
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An Alternative Process Including Sand Casting, Forging And Heat Treatment Of 30mm Diameter X48crmov8-1 Tool SteelAgacik, Ihsan Alp 01 October 2012 (has links) (PDF)
Shear blades are mostly made of cold-work tool steels and manufactured by rolling process. Rolling process is performed not only for forming the tool but also for improving the mechanical properties.
In this study, an alternative method, involving sand casting, hot forging and heat treatment processes to manufacture the shear blades, has been proposed. In the proposed method, plastic deformation will be carried out by means of forging instead of rolling. The material has been selected as X48CrMoV8-1. For both of casting and forging processes, simulations have been conducted by using Computer Aided Engineering Software. According to the results of casting process simulation, the billets have been poured. These billets have been soft annealed first and then taken as the initial raw material for the forging process. After the forging process, quenching and tempering processes have been applied.
The specimens have been taken as cast, as forged and as tempered and the microstructural analysis and mechanical tests have been performed on these. The same tests and analysis have been repeated for a commercially available shear blade sample which is manufactured by rolling. All these investigations have shown that the properties of the forged shear blade are very similar to the rolled shear blade. Therefore, the new proposed method has been verified to be used as an alternative manufacturing method for the cold-work tool steel shear blades.
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Distributed k-ary System: Algorithms for Distributed Hash TablesGhodsi, Ali January 2006 (has links)
This dissertation presents algorithms for data structures called distributed hash tables (DHT) or structured overlay networks, which are used to build scalable self-managing distributed systems. The provided algorithms guarantee lookup consistency in the presence of dynamism: they guarantee consistent lookup results in the presence of nodes joining and leaving. Similarly, the algorithms guarantee that routing never fails while nodes join and leave. Previous algorithms for lookup consistency either suffer from starvation, do not work in the presence of failures, or lack proof of correctness. Several group communication algorithms for structured overlay networks are presented. We provide an overlay broadcast algorithm, which unlike previous algorithms avoids redundant messages, reaching all nodes in O(log n) time, while using O(n) messages, where n is the number of nodes in the system. The broadcast algorithm is used to build overlay multicast. We introduce bulk operation, which enables a node to efficiently make multiple lookups or send a message to all nodes in a specified set of identifiers. The algorithm ensures that all specified nodes are reached in O(log n) time, sending maximum O(log n) messages per node, regardless of the input size of the bulk operation. Moreover, the algorithm avoids sending redundant messages. Previous approaches required multiple lookups, which consume more messages and can render the initiator a bottleneck. Our algorithms are used in DHT-based storage systems, where nodes can do thousands of lookups to fetch large files. We use the bulk operation algorithm to construct a pseudo-reliable broadcast algorithm. Bulk operations can also be used to implement efficient range queries. Finally, we describe a novel way to place replicas in a DHT, called symmetric replication, that enables parallel recursive lookups. Parallel lookups are known to reduce latencies. However, costly iterative lookups have previously been used to do parallel lookups. Moreover, joins or leaves only require exchanging O(1) messages, while other schemes require at least log(f) messages for a replication degree of f. The algorithms have been implemented in a middleware called the Distributed k-ary System (DKS), which is briefly described. / QC 20100824
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Préparation non paramétrique des données pour la fouille de données multi-tablesLahbib, Dhafer 06 December 2012 (has links) (PDF)
Dans la fouille de données multi-tables, les données sont représentées sous un format relationnel dans lequel les individus de la table cible sont potentiellement associés à plusieurs enregistrements dans des tables secondaires en relation un-à-plusieurs. Afin de prendre en compte les variables explicatives secondaires (appartenant aux tables secondaires), la plupart des approches existantes opèrent par mise à plat, obtenant ainsi une représentation attribut-valeur classique. Par conséquent, on perd la représentation initiale naturellement compacte mais également on risque d'introduire des biais statistiques. Dans cette thèse, nous nous intéressons à évaluer directement les variables secondaires vis-à-vis de la variable cible, dans un contexte de classification supervisée. Notre méthode consiste à proposer une famille de modèles non paramétriques pour l'estimation de la densité de probabilité conditionnelle des variables secondaires. Cette estimation permet de prendre en compte les variables secondaires dans un classifieur de type Bayésien Naïf. L'approche repose sur un prétraitement supervisé des variables secondaires, par discrétisation dans le cas numérique et par groupement de valeurs dans le cas catégoriel. Dans un premier temps, ce prétraitement est effectué de façon univariée, c'est-à-dire, en considérant une seule variable secondaire à la fois. Dans un second temps, nous proposons une approche de partitionnement multivarié basé sur des itemsets de variables secondaires, ce qui permet de prendre en compte les éventuelles corrélations qui peuvent exister entre variables secondaires. Des modèles en grilles de données sont utilisés pour obtenir des critères Bayésiens permettant d'évaluer les prétraitements considérés. Des algorithmes combinatoires sont proposés pour optimiser efficacement ces critères et obtenir les meilleurs modèles.Nous avons évalué notre approche sur des bases de données multi-tables synthétiques et réelles. Les résultats montrent que les critères d'évaluation ainsi que les algorithmes d'optimisation permettent de découvrir des variables secondaires pertinentes. De plus, le classifieur Bayésien Naïf exploitant les prétraitements effectués permet d'obtenir des taux de prédiction importants.
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