Search results for "VDP::Mathematics and natural science: 400::Mathematics: 410"
showing 10 items of 248 documents
Missing Value Estimation for Microarray Data by Bayesian Principal Component Analysis and Iterative Local Least Squares
2013
Published version of an article from the journal: Mathematical Problems in Engineering. Also available from Hindawi: http://dx.doi.org/10.1155/2013/162938 Missing values are prevalent in microarray data, they course negative influence on downstream microarray analyses, and thus they should be estimated from known values. We propose a BPCA-iLLS method, which is an integration of two commonly used missing value estimation methods-Bayesian principal component analysis (BPCA) and local least squares (LLS). The inferior row-average procedure in LLS is replaced with BPCA, and the least squares method is put into an iterative framework. Comparative result shows that the proposed method has obtaine…
Mathematical modeling and parameters estimation of a car crash using data-based regressive model approach
2011
Author's version of an article in the journal: Applied Mathematical Modelling. Also available from the publisher at: http://dx.doi.org/10.1016/j.apm.2011.04.024 n this paper we present the application of regressive models to simulation of car-to-pole impacts. Three models were investigated: RARMAX, ARMAX and AR. Their suitability to estimate physical system parameters as well as to reproduce car kinematics was examined. It was found out that they not only estimate the one quantity which was used for their creation (car acceleration) but also describe the car's acceleration, velocity and crush. A virtual experiment was performed to obtain another set of data for use in further research. An A…
Effect of a finite external heat transfer coefficient on the Darcy-Bénard instability in a vertical porous cylinder
2013
Publised version of an article from the journal: Physics of Fluids. Copyright (2013) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. Article appears in Volume 25 issue 4 of the journal: http://dx.doi.org/10.1063/1.4799253 The onset of thermal convection in a vertical porous cylinder is studied by considering the heating from below and the cooling from above as caused by external forced convection processes. These processes are parametrised through a finite Biot number, and hence through third-kind, or Robin, temperature conditions imposed on the lower and upper b…
Investigating the affordances of a flipped mathematics classroom from an activity theoretical perspective
2020
Abstract Flipped Classroom as a pedagogical framework has gained popularity at secondary and tertiary levels of mathematics education, but there is a lack of research based on a solid theoretical foundation. This article considers the flipped mathematics classroom from the perspective of affordances and cultural–historical activity theory. The empirical background is based on semi-structured interview data from eight first-year computer-engineering students following 1 year of flipped classroom teaching. The thematic analysis of the data indicates that the flipped format offers a range of affordances at various levels of the activity system. This article advances research on affordances for…
Reasoning with paper and pencil: The role of inscriptions in student learning of geometric series
2009
The purpose of this article is to analyse how students use inscriptions as tools for thinking and learning in mathematical problem-solving activities. The empirical context is that of learning about geometric series in a small group setting. What has been analysed is how students made use of inscriptions, self-made as well as those provided by text books and teachers, and the role these inscriptions played in the coordination of students’ learning/communication. Through the use of inscriptions (made on the chalkboard and with paper and pencil), the students externalised their thinking while engaging in mathematical reasoning on the topic of geometric series. The inscriptions were significan…
Et introduksjonskurs til GeoGebra : en designstudie av introduksjonskurset med fokus på å lære å bruke i 1T i videregående skole
2016
Masteroppgave matematikkdidaktikk – Universitetet i Agder 2016 As a teacher, I have observed over the past years a change in focus on the use of tools in the teaching of mathematics. Starting in spring 2015 the use of digital tools by students will be a requirement in the examinations in mathematics at high school level. This means that teachers must be even more aware of how we can best help our students to master the use of such tools while refining their understanding of mathematics. The aim of my study was to find a way to introduce GeoGebra (a mathematical tool with options for dynamic geometry, for plotting functions, and for CAS) to students in grade 11. The introduction should be su…
A Spatio-temporal Probabilistic Model of Hazard and Crowd Dynamics in Disasters for Evacuation Planning
2013
Published version of a chapter in the book: Recent Trends in Applied Artificial Intelligence. Also available from the publisher at: http://dx.doi.org/10.1007/978-3-642-38577-3_7 Managing the uncertainties that arise in disasters – such as ship fire – can be extremely challenging. Previous work has typically focused either on modeling crowd behavior or hazard dynamics, targeting fully known environments. However, when a disaster strikes, uncertainty about the nature, extent and further development of the hazard is the rule rather than the exception. Additionally, crowd and hazard dynamics are both intertwined and uncertain, making evacuation planning extremely difficult. To address this chal…
Euclid’s Proof of the Infinitude of Primes: Distorted, Clarified, Made Obsolete, and Confirmed in Modern Mathematics
2014
Published version of an article in the journal: Mathematical Intelligencer. Also available from the publisher at: http://dx.doi.org/10.1007/s00283-014-9506-9
Rockefeller Philanthropy and Mathematical Emigration between World Wars
2015
Published version of an article in the journal: The Mathematical Intelligencer. Also available from the publisher at: http://dx.doi.org/10.1007/s00283-014-9530-9 This article discusses one aspect of Rockefeller support for mathematics: the emigration of mathematicians from Europe. For the broader policies of the Rockefeller philanthropies for internationalization of mathematics, see my monograph Siegmund-Schultze (2001), which together with other sources will be broadly used in the following and will be quoted as RI.
Emigration of mathematicians from outside German-speaking academia 1933-1963, supported by the Society for the Protection of Science and Learning
2012
Author's version of an article published in the journal: Historia Mathematica. Also available from the publisher at: http://dx.doi.org/10.1016/j.hm.2011.08.002 Racial and political persecution of German-speaking scholars from 1933 onward has already been extensively studied. The archives of the Society for the Protection of Science and Learning (SPSL), which are deposited in the Western Manuscripts Collection at the Bodleian Library in Oxford, is a rich source of information about the emigration of European scientists, also those who did not come from German-speaking institutions. This is an account of the support given by the SPSL to the persecuted mathematicians among them. The challenges…