El número en la escuela

El artículo “El Número en la Escuela”presenta avances de investigación realizados por estudiantes de la Maestría en Docencia de las Matemáticas de la Universidad Pedagógica Nacional como parte de sus respectivos trabajos de grado. El primero, referido a la formación de docentes de preescolar y primeros grados de educación primaria sobre Estructura Aditiva, expone la forma en que abordar dicha estructura contribuye al proceso de construcción del número Natural en los primeros grados de escolaridad. El segundo, basado en el modelo del profesor Carlo Federici, estudia la construcción de los números racionales como operadores sobre magnitudes, específicamente, sobre longitudes cuya representación son los segmentos. Y el tercero, permite reflexionar sobre el acercamiento al concepto de número real con estudiantes de Secundaria y Media

Consideraciones históricas para la enseñanza de la derivada

Some methods that were developed throughout history to find derivatives from Apolonio de Perga to Cauchy are presented, then itineraries are proposed for the introduction of the derivative in the curriculum: addressing positions of the theory of Action, Process, Object and Scheme (APOE) and the tools proposed by the known as the Onto-Semiotic Approach (OSA), for elements of the derivative before the limit and limits before derivatives. From these, semiotic representations are proposed that allow to approach the derivative (numerical, algebraic, formal, geometric, infinitesimal, local, variational and computational related approximation). Finding that the concept as taught today does not coincide with the development of its genesis and that a way of understanding the concept of derivatives from the use of treatments and conversions of registers of representation.Se presentan algunos métodos que se desarrollaron a través de la historia para encontrar derivadas desde Apolonio de Perga hasta Cauchy. A partir de estos, se plantean representaciones semióticas que permiten abordar la derivada (numérico, algebraico, formal, geométrico, infinitesimal, aproximación afín local, variacional y computacional). Encontrando que el concepto como se enseña en la actualidad no coincide con el desarrollo de su génesis y que una forma de comprender el concepto de derivadas a partir de uso de tratamientos y conversiones de registros de representación

Development of a Large Scale Infiltration Tank for Determination of the Hydraulic Properties of Expansive Clays

International audienceA large-scale infiltration tank was developed to study the water transfer in compacted expansive clay. Volumetric water content sensors were buried in a soil column for water content monitoring during infiltration. In addition to water content, soil suction and temperature at various locations and the heave at the soil surface were also monitored. Emphasis was put in minimizing the effect of sensors installation on water transfer and soil deformation. The results obtained for 338-days of infiltration were presented in terms of changes of suction, volumetric water content, temperature and the soil heave. Based on the recorded data, the performance and limitation of different suction and volumetric water content sensors and the adopted test procedure were analyzed. The recorded data on soil suction and volumetric water content were finally analyzed for determining the unsaturated hydraulic properties of soil such as the water retention curve and the unsaturated hydraulic conductivity. Note also that the results constitute useful data for further physical analysis or numerical models calibration

Significados que los estudiantes de ingeniería confieren a la antiderivada

In this article, are presented the results of a questionnaire designed to evaluate college students’ understanding of the antiderivative. Specifically, by civil engineering students when answering the questionnaire tasks, in order to identify and characterize the meanings on the antiderivative that are developed by them. In order to analyse the answers given, were used some theoretical and methodological notions provided by the theoretical model known as the Onto-Semiotic Approach (OSA) of mathematics cognition and instruction. The results show the knowledge of antiderivative by the Civil Engineering students. Furthermore, the comparison between the mathematical activity of students provides information that allows concluding that the meanings that they mobilized might be shared among their communitiesEn este artículo, se presentan los resultados de un cuestionario diseñado para evaluar la comprensión de los estudiantes universitarios de la antiderivada. Específicamente, por estudiantes de ingeniería civil al responder las tareas del cuestionario, con el fin de identificar y caracterizar los significados sobre la antiderivada que son movilizados por ellos. Para analizar las respuestas dadas, utilizamos algunas nociones teóricas y metodológicas proporcionadas por el modelo teórico conocido como Enfoque Ontosemiótico (EOS) del conocimiento y la instrucción matemática. Los resultados muestran el conocimiento de la antiderivada por parte de los estudiantes de Ingeniería Civil. Además, la comparación entre la actividad matemática de los estudiantes proporciona información que permite concluir que los significados que movilizaron podrían compartirse entre sus comunidade

Algunos métodos de interpolación para generar un modelo digital de elevación

El uso de puntos de control y la generación de las mallas geodésicas permiten la elaboración de mapas y modelos cartográficos digitales de terreno. La elección de estos puntos se debe realizar en torno a un criterio de interpolación que permita minimizar la generación de errores en la elaboración de un modelo digital. Por tal razón, en el presente artículo se muestra que existe un único polinomio que interpola un conjunto finito de puntos del plano con abscisas distintas y se presentan algunas formas de obtener este polinomio; entre ellas, el polinomio de interpolación de Newton (1687), el polinomio de Lagrange (1775), el método matricial y el método de diferencias divididas

Cros (Françoise), Adamczewski (Georges). — L'innovation en éducation et en formation

Pastiaux-Thiriat Georgette. Cros (Françoise), Adamczewski (Georges). — L'innovation en éducation et en formation. In: Revue française de pédagogie, volume 123, 1998. La violence à l'école : approches européennes. pp. 169-170

FLUID-STRUCTURE INTERACTION : EFFECTS OF SLOSHING IN LIQUID-CONTAINING STRUCTURES

This report presents the work done within the framework of my master thesis in the program Infrastructure Engineering at KTH Royal Institute of Technology, Stockholm. This project has been proposed and sponsored by the French company Setec TPI, part of the Setec group, located in Paris. The overall goal of this study is to investigate fluid-structure interaction and particularly sloshing in liquid-containing structures subjected to seismic or other dynamic action. After a brief introduction, the report is composed of three main chapters. The first one presents and explains fluid-structure interaction equations. Fluid-structure interaction problems obey a general flow equation and several boundary conditions, given some basic assumptions. The purpose of the two following chapters is to solve the corresponding system of equations. The first approach proposes an analytical solution: the problem is solved for 2D rectangular tanks. Different models are considered and compared in order to analyze and describe sloshing phenomenon. Liquid can be decomposed in two parts: the lower part that moves in unison with the structure is modeled as an impulsive added mass; the upper part that sloshes is modeled as a convective added mass. Each of these two added mass creates hydrodynamic pressures and simple formulas are given in order to compute them. The second approach proposes a numerical solution: the goal is to be able to solve the problem for any kind of geometry. The differential problem is resolved using a singularity method and Gauss functions. It is stated as a boundary integral equation and solved by means of the Boundary Element Method. The linear system obtained is then implemented on Matlab. Scripts and results are presented. Matlab programs are run to solve fluid-structure interaction problems in the case of rectangular tanks: the results concur with the analytical solution which justifies the numerical solution. This report gives a good introduction to sloshing phenomenon and gathers several analytical solutions found in the literature. Besides, it provides a Matlab program able to model effects of sloshing in any liquid-containing structures

L'Incidence de la réforme du droit des contrats sur la cause des libéralités (donations et testaments)

Droit privéFace à la multiplicité et à l’importance des rôles joués par la cause en matière de libéralité, l’on peut légitimement se demander quelle incidence a eu la suppression de la notion de cause par la réforme du droit des contrats et si cette incidence en matière de libéralité ne consiste pas principalement en une consécration par le législateur, des solutions anciennement adoptées sur le fondement de la cause