TinyMCE supports only standard HTML math
symbols, we extended its library with a module for
handling mathematical expressions. Once entered,
these are rendered into images using the
LatexRender scripts
(http://www.mayer.dial.pipex.com/tex.htm).
All MatPort printouts have the standard PDF
(Portable Document Format) format.
The MatPort forum is based upon the PHPBB
TM
(http://www.phpbb.com/) open-source forum
solution.
Last but not least, we set formatting MatPort
visual options in a centralized document that is
referenced from PHP files by using CSS (Cascading
Style Sheets).
3 DECISION SUPPORT SYSTEM
We are aware of the fact that only providing a
dataset of math items is not enough. We need to
incorporate an extrinsic motivation system to
“bribe” the 6
th
to 9
th
grade students to practice
mathematics. There are rare children who are
intrinsically motivated to do repetitive, boring tasks.
3.1 How to Motivate Children?
A student who solves a MatPort math item receives
information on the progress through graphical
symbols and stimulative words (Fig. 2).
In addition, the application provides information
on math items that need to be further solved to
receive a higher score. These can be supplementary
or additional items to help strengthen or increase
knowledge, respectively. The information is
provided by the MatPort decision support system,
when the automatic search facility is used.
3.2 Genetic Algorithm
The MatPort decision support system that motivates
students to continue solving exercises is based upon
an evolutionary computation method, i.e., the
genetic algorithm (GA) (Goldberg, 1989; Bäck,
1996).
The GA is based on a heuristic method, which
requires little information to search effectively in a
large search space. The algorithm employs an initial
population of chromosomes, which evolve to the
next generation by probabilistic transition rules
(randomized genetic operators) such as selection,
crossover and mutation. The objective function
evaluates the quality (fitness) of solutions coded as
chromosomes. This information is used to perform
an effective search for better solutions. There is no
need of other auxiliary knowledge. The GA tends to
take advantage of the fittest solutions by giving them
greater weight and by concentrating the search in the
regions of the search space with likely improvement.
The GA mechanism is presented in Fig. 7.
Initialize the population of
chromosomes;
While stop condition not met do:
Calculate the fitness for each
member in the population using the
fitness function
;
Select and reproduce individuals
according to their fitness;
Perform genetic operators
(crossover and mutation) on the
population.
Figure 7: The GA’s pseudocode.
The GA is a population-based evolutionary
approach that allows searching within a broad set of
solutions from the search space simultaneously.
Namely, because there are many math items (few
hundreds or even more than thousand math items per
a grade) and interrelated content areas (more than
100 content areas per a grade), the student may
continue solving items in many possible ways that
may or may not lead to a higher score. Moreover,
math items are dynamically generated by teachers
(i.e., the item dataset expands with time) and the
student may start solving them anywhere in the
dataset. In the GA, there is a risk of converging to a
local optimum, but good results of various research
work obtained in other optimization problem areas
(Papa and Koroušić Seljak, 2005; Koroušić Seljak,
2006; Tušar et al, 2007; Korošec and Šilc, 2008)
encouraged us to consider the GA approach as a
promising approach to the decision making problem.
The idea is to find a set of math items within
different content areas that, when solved
correctly, improve the user’s knowledge and
increase his/her score as much as possible. The set
of items should consist of math problems from all
poorly scored content areas and the areas that
precede these areas. Therefore, before start
searching, the system identifies all the feasible
items, i.e., math problems from the poorly scored
content areas. These items form some kind of a pool
of relevant items P for current score improvement.
3.2.1 Encoding
The suggested list of math items needed to improve
the score is encoded into a chromosome, where each
MATHPORT - Web Application to Support Enhancement in Elementary Mathematics Pedagogy
85