Prsentation PowerPoint

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Colloque ITEM REIMS 20-22 juin 2003
Description and analysis of a post bac vocational
teaching using graphing software Gérard
CHAUVAT IUT-GEII Tours IUFM Orléans-Tours
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• Maths teaching organization today
• Audience Hardware
• Lecture 130 students, 1 computer connected to a
  videoprojector, 4m large screen. (32 weeks x 1.5H
  the 1st year 18w x 1.5H the 2nd year)
• Training work group 28 students, 1 movable
  computer connected to a videoprojector, 1.5m
  large screen. (32w x 3H 18w x 1.5H)
• ½ work group 14 students, 14 network computers.
  (10w x 1H30 including 2 x 3/4H for examination)
• Intranet free access for each student.

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• Maths teaching organization today
• 1st year used softwares
• Lecture ORGE, Cabri-géomètre, GéoplanW,
  GéospaceW, Maple V.
• Training work group ORGE, Maple V.
• ½ work group ORGE, Maple V.
• ORGE is a grapher for relationships between reals
  (free available on
• www.iut.univ-tours.fr/tpweb/geii/orgehome.htm).

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• Maths teaching organization today
• 2nd year used softwares
• Lecture ORGE, GéoplanW, GéospaceW, Excel, Maple
  V.
• Training work group ORGE.
• ½ work group Excel.

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• Maths teaching organization today
• Differents uses for software
• Lecture illustration, visualization. (teacher
  topos)
• Training work group check control ,
  heuristic, experimentation. (teacher and student
  topos)
• ½ work group learning situation,
  experimentation, control, calculation. (student
  topos)

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Lecture example spectral analysis and ideal
filtering
f(t) t sin(2pt) The aim is to remove the
sine component (assumed unknown )
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Lecture example spectral analysis and ideal
filtering
ORGE is able to compute FFT of f (Menu item
Actions Transformées Transfo. de Fourier)
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Lecture example spectral analysis and ideal
filtering
Real part
Imaginary part
Complex spectrum of f
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Lecture example spectral analysis and ideal
filtering
So we can proceed in frequency domain.
First, we convert each spectrum in time serie.
(Menu item Courbes Transfert en chronique)
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Lecture example spectral analysis and ideal
filtering
Then we remove the sine component from imaginary
part.
(Menu item Courbes Modifier)
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Lecture example spectral analysis and ideal
filtering
We get the new time serie below.
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Lecture example spectral analysis and ideal
filtering
Finally, ORGE compute the inverse FFT and give
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Lecture example spectral analysis and ideal
filtering
what we expected !!
Filtered signal in black
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Example
How to sample s(t)-Acos2pn0t to get back g(t) and
d(t)
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• Some conclusions
• To make credible the computational tools
  integration,
• it seems necessary to satisfy the following
  conditions
• An institutionnal will.
• Significant financial and material means.
• Appropriate formation (vocational training) for
  teachers, especially about didactic engineering.

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Some conclusions The computational tools
integration must be complete, i.e. present in
every device of the didactical organization pay
ing attention to consistent and complementary
aspects of its differents uses.
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Some conclusions Springboard for some students,
hindrance for others, the use of computationnal
tools must stay focused on knowledge purpose.
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Some conclusions It seems very hard to prove
that our use of software to teach maths is
profitable for our students. Our only answer,
now, is theoretical !