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FROM OSCILLATIONS TO NORMAL MODES: AN EDUCATIONAL PATH FOR THE UPPER SECONDARY SCHOOL
Full text linkThe present thesis work starts from the assumption that harmonic oscillations and
normal modes are key physical concepts. They are fundamental in quantum physics,
in electromagnetism (especially in treating coupled oscillating circuits and electromagnetic
waves), in acoustics and in mechanical systems. The conceptual and practical
importance of normal modes emerges also clearly from the fact that every small
and sufficiently smooth oscillation of a complex system is given by a linear superposition
of its normal modes. The notion of normal modes is thus a powerful conceptual
organizer. Nevertheless, in teaching practice (at least in Italy), only short time is
devoted to harmonic motion, rarely coupled oscillators are treated and, in secondary
school text-books, normal modes are usually not even present. The purpose of this
thesis work is to develop an effective path on scillations for the upper secondary
school that leads to the normal modes of oscillations. To do this, an educational reconstruction
of the concept of harmonic motion has been necessary as the harmonic
motion is a fundamental prerequisite for the understanding of normal modes. The
introduction of normal modes is, for upper secondary school students, complicated
by the complexity of the mathematics involved. In our path we propose to overcome
the mathematical difficulties through an experimental approach and the use of different
tools such as video and picture analysis, also in slow motion, data logging and
data analysis techniques and applet simulations, with the goal of being as simple
as possible from the mathematical point of view but without losing the advantages
that mathematics (even at simple level) can provide. In this perspective, a multiple
representation approach has been used. The path on oscillations that we present
here is the result of a Design Based Research on normal modes with Italian upper
secondary school students. The complete path has been proposed to three classes of
11th grade students during curricular lessons. A version of the sequence has been
proposed also to other three classes (one of grade 11th and two of grade 12th) during
afternoon extra-curricular lessons, and a version with university-level formalism has
also been proposed to a group of undergraduate students in mathematics during
the third year course “Preparation of Didactical Experiments”. A reduced version
of the path has also been proposed to a number of classes of 12th grade students
within the one-shot lessons on oscillations (afternoon extra-curricular activities) in
the framework of PLS (Piano Lauree Scientifiche) activities. The one-shot lessons
have been attended, over time, by about six hundred students.
The all path is based on a number of activities in which we start from a real experiment
or a video or else an applet simulation to introduce and discuss a limited
topic. The general purpose is to identify, among the oscillations, those that give rise
to a peculiar kind of motion, the harmonic motion, and determine the conditions
under which such motion can be obtained. A number of significant situations of
harmonic and anharmonic motions are investigated and criteria to establishing the
harmonicity/anharmonicity of the oscillation are discussed. An important tool for
the analysis of the data is then introduced: the Fast Fourier Transform. The FFT is
introduced as a tool and not discussed through mathematics. Then the concept on
resonance is introduced in a phenomenological way through experiments and exploring
related videos in the Internet videos database. The next step is the introduction
of the coupling between two oscillators and the discovery of particular motion configurations:
the Normal Modes of Oscillation. We then extend the experiments to
three, four, five....many coupled oscillators until we arrive to the continuous case;
first in one dimension with the string and then in two dimensions with the Cladni
plates and we study the normal modes of such complex systems.
The structure of the thesis is as follows: an introduction to the motivations, a description
of the state of the art and the formulation of the research questions. Then
a brief description of the methodological framework mainly based on the Design
Based Research approach and the Model of the Educational Reconstruction. The
reconstruction of the Harmonic motion at university level follows; the translation
of such a reconstruction into upper secondary school level is developed in chapter
five. In chapter four normal modes for a system of two, three, N coupled oscillators
are treated with the proper formalism; also in this case the translation into upper
secondary school level is developed in chapter five. Then the very core of the thesis
follows , namely the developing of the path, as briefly described above. The next
chapter reports a path developed with undergraduate students as an implementation
of the study of oscillations. It is the study of the modes of oscillation in the interesting
case of a parametric oscillator were there is a non-linear coupling between modes
of oscillation. In the last section, the main results of the experimentation of the path
with threes classes of 11th grade students are briefly presented. These results are
based on questionnaires (pre-test and post-test), discussions and interviews
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
A guided inquiry based teaching and learning sequence on oscillations based on experiments and data-logging techniques
Full text linkWe present here a teaching and learning sequence on oscillations entirely based on
experiments and data logging techniques. The sequence has been proposed to three
different groups of students during curricular and extracurricular lessons. The purpose of
this paper is to discuss a way to introduce upper secondary school students to complicated
topics, such as those of coupled oscillations, avoiding the use of too much mathematics and
calculus, but with an intense use of data logging techniques
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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