Search results for "problems"

Calculus Artefacts in Chinese Textbooks: Variational Approaches with Prospective Primary Teachers

2022

The first part of the paper presents some theoretical reflections and some methodological notes about a Professional Development (PD) path worked out during the last two years by Italian researchers for prospective primary teachers. The theoretical construct of Cultural Transposition defines the framework of the PD path’s activities and the related research. It was used to define an interesting cultural lens to delineate possible new approaches for effective pre-service teacher education programs in particular for the primary level. The defined methodology was based on the possibility to reflect on the he decentralization of didactic practices based on a specific cultural context through on…

Engaging universities in social innovation research for understanding sustainability issues

2017

International audience; The paper presents the analysis of a three-stage research conducted by the authors within a social innovation project in collaboration with international master students of Riga Technical University for determining the factors, which motivate people to be involved in the solution of social problems. The authors not only analyse and use the outcomes of the students’ research but also provide feasibility study of using the potential of study research at the university, for implementing serious research projects. Data collection from Africa, Asia, America and Europe was organised jointly by all the students via web-based survey for creating an original data base for the…

Cuatro años de la versión computerizada del Examen de Inglés como segunda lengua (TOEFL)

2009

Este artículo trata señalar las dificultades a las que se enfrentan los candidatos cuando realizan el examen de inglés como lengua extranjera (TOEFL) basado en Internet. El objetivo es doble: por un lado ver cómo se puede sugerir cómo evitar problemas similares en plataformas que ya se están diseñando en España (Proyecto PAULEX, MEC HUM2007-66479-C02-01/FILO) y, por otro, poner de relieve el tipo de preparación que necesitan los estudiantes que realicen este examen para poder superar ciertos problemas estratégicos que actualmente encuentran dichos candidatos.

Distributed Data Clustering via Opinion Dynamics

2015

We provide a distributed method to partition a large set of data in clusters, characterized by small in-group and large out-group distances. We assume a wireless sensors network in which each sensor is given a large set of data and the objective is to provide a way to group the sensors in homogeneous clusters by information type. In previous literature, the desired number of clusters must be specified a priori by the user. In our approach, the clusters are constrained to have centroids with a distance at least ε between them and the number of desired clusters is not specified. Although traditional algorithms fail to solve the problem with this constraint, it can help obtain a better cluste…

Challenging aspects in Consensus protocols for networks

2008

Results on consensus protocols for networks are presented. The basic tools and the main contribution available in the literature are considered, together with some of the related challenging aspects: estimation in networks and how to deal with disturbances is considered. Motivated by applications to sensor, peer-to- peer, and ad hoc networks, many papers have considered the problem of estimation in a consensus fashion. Here, the unknown but bounded (UBB) noise affecting the network is addressed in details. Because of the presence of UBB disturbances convergence to equilibria with all equal components is, in general, not possible. The solution of the epsiv-consensus problem, where the states…

MAD+. Introducing Misconceptions in the Temporal Analysis of the Mathematical Modelling Process of a Fermi Problem

2021

This work describes how the combination of the mistakes committed by a group of pre-service teachers when solving a Fermi problem, with the representation of the temporal analysis of their resolutions, can offer more in-depth information about their conceptual misconceptions regarding mathematical and modelling concepts. The combined representation allows knowing when mistakes occur and provides a powerful tool for instructors to adapt the teaching–learning processes of mathematics at all levels of education. Our study is based on a recent categorisation of students’ mistakes, together with the creation of a new representation tool, called MAD+, that can combine all this information. The ma…

Epistemic and didactic values of the demonstrative process in different cultures: a case study in Geometry with Chinese and Italian students

2011

Associations of Maternal Cell-Phone Use During Pregnancy With Pregnancy Duration and Fetal Growth in 4 Birth Cohorts

2019

Results from studies evaluating potential effects of prenatal exposure to radio-frequency electromagnetic fields from cell phones on birth outcomes have been inconsistent. Using data on 55,507 pregnant women and their children from Denmark (1996-2002), the Netherlands (2003-2004), Spain (2003-2008), and South Korea (2006-2011), we explored whether maternal cell-phone use was associated with pregnancy duration and fetal growth. On the basis of self-reported number of cell-phone calls per day, exposure was grouped as none, low (referent), intermediate, or high. We examined pregnancy duration (gestational age at birth, preterm/postterm birth), fetal growth (birth weight ratio, small/large size…

Autoestima, percepción de estrés y ánimo depresivo en grupos de riesgo.

2001

Los grupos de riesgo se caracterizan por una mayor vulnerabilidad a desarrollar problemas psicológicos y sociales y, por tanto, suelen ser los destinatarios prioritarios de muchas de las intervenciones realizadas por los trabajadores sociales. En este sentido, en esta investigación se analizan tres variables psicológicas que pueden estar relacionadas con la mayor vulnerabilidad de los diversos grupos de riesgo- En concreto, se comparan las variables de autoestima, percepción de estrés y ánimo depresivo en personas que manifiestan un problema de salud física como es la hipertensión (n=30) y en personas con un problema de tipo psicosocial como es el consumo abusivo de alcohol (n=47) en relaci…

Stability of degenerate parabolic Cauchy problems

2015

We prove that solutions to Cauchy problems related to the $p$-parabolic equations are stable with respect to the nonlinearity exponent $p$. More specifically, solutions with a fixed initial trace converge in an $L^q$-space to a solution of the limit problem as $p>2$ varies.