Graz University of Technology
1
Taraghi, Stickel, Ebner EFEPLE, 30.03.2011
Survival of the Fittest – Utilization of Natural
selection Mechanisms for Improving PLE
Behnam Taraghi, Christian Stickel, Martin Ebner
Graz University of Technology
2
Taraghi, Stickel, Ebner EFEPLE, 30.03.2011
http://ple.tugraz.at
Mashup of
widgets
Graz University of Technology
3
Taraghi, Stickel, Ebner EFEPLE, 30.03.2011
Darwin’s theory
- Survival of the fittest
- Selection, Variation
- Macro evolution
- Micro evolution
Graz University of Technology
4
Taraghi, Stickel, Ebner EFEPLE, 30.03.2011
Selections
Evolution theory of natural selections:
- Reproduction rate- Mortality- Population size- Environmental capacity
- Cycle of updates, replacements & new widgets- # widgets- Max # widgets on UI & # users
Different probabilities for the survival are the base for the selection mechanism.
Graz University of Technology
5
Taraghi, Stickel, Ebner EFEPLE, 30.03.2011
Selection Mechanisms*
Stabilizing Selection:- Favorites the average.- Decrease of variability within the population.
Disruptive Selection:- Directed against the average.- Splits the population into new species.
Directed Selection:- Works against individuals on one side of distribution.
*Solbrig O.T. (1970). Principles and Methods of Plant Biosystematics. The Mac-Millan Company. Collier-Mac Millan Limited, London.*Solbrig O.T. & D.J Solbrig. (1979). Populationbiology and evolution. Addision-Wesley. Publ. Co. Reading Mass.
Graz University of Technology
6
Taraghi, Stickel, Ebner EFEPLE, 30.03.2011
r/K Selection Theory*Tradeoff btw. quantity & quality of offspring
In long term K-strategy is superior.Quality succeeds in long run over quantity.
r-Strategy- Succeeds in unpredictable, unknown environments.- High reproduction rate – short lifespan
K-Strategy- Succeeds in predictable, known environments.- Constant growth, ruled by population density & env. capacity- Usually close to the max. capacity- Slower adaptation – longer lifespan
In PLE a mixed approach was applied.
*Pianka E.R. (1970). On r and K selection. American naturalist 104, 592-597.*MacArthur, R. and Wilson, E.O. (1967). The Theory of Island Biography, Princeton University Press (2001 reprint).
Graz University of Technology
7
Taraghi, Stickel, Ebner EFEPLE, 30.03.2011
VariationsShift in genotypes or generic sequence
- Mutation:- Random process aiming at generation of new alternatives- Ex. change in DNA structure- Continuously happening
- Recombination:- Not random process- Combining & distributing genetic materials (DNA, RNA)
The Evolution never stops.In PLE: slight update of existing functionality or UI
In PLE: combining code of different widgets to build new ones
Graz University of Technology
8
Taraghi, Stickel, Ebner EFEPLE, 30.03.2011
Tracking module in PLE
-Tracks users’ behavior on widgets- Deep retrieve of statistics data
- Frequency of widgets usage- Features used in each widget
- Realized via IWC
- App. 1000 users registered up to now.- App. 30% active users- Top 5 most used widgets out of 30:
- tugWidget, tccourses, tugllBlogs, mail, changeThemeColor- Top 5 most activated widgets:
- weatherForcast, RSSReader, twitter, TUGLibrary, leoDictionary- weatherForcast & newsgroup are improved according to K-strategy
Most activated widgets are not necessarily most used ones
Graz University of Technology
9
Taraghi, Stickel, Ebner EFEPLE, 30.03.2011
Conclusion & Future Work
- Tracking module helps- To get knowledge about user behavior
- To get user preferences
- To categorize different user groups
- Improve the PLE with variations & selections
- Missing qualitative data- Qualitative rating system is needed in PLE
- Small feedback questionnaire for each widget
Graz University of Technology
10
Taraghi, Stickel, Ebner EFEPLE, 30.03.2011
SOCIAL LEARNING
Computer and Information Services
http://tugraz.at
http://elearning.tugraz.at
Slides available at: http://www.slideshare.net/behi_at
b.taraghi(at)tugraz.at
