Social sharing by means of distributed computing some results from a study of seti@home
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‘Social Sharing’ By Means of Distributed Computing: Some Results From A Study of SETI@home. Hans-J ürgen Engelbrecht Massey University August 2005 H.Engelbrecht@massey.ac.nz http://www.massey.ac.nz/~hengelbr/. 1. Introduction.

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Social sharing by means of distributed computing some results from a study of seti@home

‘Social Sharing’ By Means of Distributed Computing: Some Results From A Study of SETI@home

Hans-Jürgen Engelbrecht

Massey University

August 2005

H.Engelbrecht@massey.ac.nz

http://www.massey.ac.nz/~hengelbr/


1 introduction
1. Results From A Study of SETI@homeIntroduction

  • Information and Communication Technologies (ICT) are General Purpose Technologies.

  • One of many associated innovations: Distributed computing, grid computing.

  • Enables non-commercial sharing of physical, rivalrous goods via the Internet: Such ‘social sharing’ is a form of economic production (Benkler, 2004).


Shareable goods
‘Shareable goods’ Results From A Study of SETI@home

  • Sharing of computing power and bandwidth.

  • Two features of ‘shareable goods’ (Benkler, 2004):

    • They are lumpy (PCs come in discrete units).

    • They are of ‘mid-grained’ granularity (PCs are widely privately owned and systematically have slack capacity).


Shareable goods ctd
‘Shareable goods’ ctd. Results From A Study of SETI@home

  • What determines the extent of ‘social sharing’?

    Technological conditions, but also cultural practices and tastes (Benkler, 2004) and social and legal conditions (David, 2004).


2 seti@home
2. Results From A Study of SETI@homeSETI@home

  • Prime example of a voluntary non-commercial Internet-based distributed computing project: SETI@home.

  • Launched in May 1999.

  • Download screen saver.

  • Analysis of Arecibo radio telescope data.

  • SETI@home the most powerful special purpose supercomputer in the world.


Seti@home ctd
SETI@home ctd. Results From A Study of SETI@home

  • Worldwide phenomenon (except for Mauritius, Palestine and Vatican City).

  • Incentives build into client interface, e.g. user and results data.

  • By Dec. 2004, there had been:

    • More than 5 million contributors.

    • Providing over 2 million years of CPU time (more than 1000 years of CPU time during the last day alone).


Seti@home ctd1
SETI@home ctd. Results From A Study of SETI@home

  • SETI country data available for: Dec. 10th, 2002; Dec. 11th, 2003; Dec. 13th, 2004.

  • Dependent variables used in the regression model:

    • SETI participants per capita.

    • SETI results per capita(measures actual outcomes and is arguably a better Internet-intensity variable than ‘hours of use’).


3 explanatory variables
3. Results From A Study of SETI@homeExplanatory variables

  • What determines SETI@home cross-country participation and its intensity?

  • Aim: To include as many countries as possible.

  • Therefore, modelling is severely restricted and I use only a few key explanatory variables in the regressions:

    • ITU’s ‘Digital Access Index’ (DAI).

    • GDP per capita (gdp).

    • The ‘Human Development Index’ (HDI).

    • Country group dummy variables.


The digital access index dai
The Digital Access Index (DAI) Results From A Study of SETI@home

  • ITU: The DAI tries to measure “the overall ability of individuals in a country to access and use ICTs…”. It provides the first truly global ICT ranking.

  • The DAI is a composite index made up of 8 underlying indicators to capture:

    • infrastructure (fixed telephone & mobile telephone subscribers),

    • affordability (Internet access price),

    • ‘knowledge’ (adult literacy, school enrolment),

    • quality (broadband subscribers, international Internet bandwidth),

    • actual usage of ICTs (Internet users).


Components of the digital access index dai 2002
Components of the Digital Access Index (DAI), 2002: Results From A Study of SETI@home


The dai ctd
The DAI ctd. Results From A Study of SETI@home

  • Hypothesis:

    The DAI is a positive and statistically significant determinant of SETI@home participation and its intensity.

    • This would mean: On average, SETI@home participation and its intensity across countries matches inter-country differences in ICT accessibility.


Other explanatory variables
Other explanatory variables Results From A Study of SETI@home

  • GDP per capita (in PPP adjusted US $):

    • Traditional proxy for ‘standard of living’. Key explanatory variable in numerous ICT and Internet diffusion studies.

    • It is expected to be a positive and statistically significant determinant of SETI@home participation and its intensity.


Other explanatory variables ctd
Other explanatory variables ctd. Results From A Study of SETI@home

  • The HDI:

    • A composite index which has emerged as the preferred measure of ‘development’.

    • It measures important dimensions of human development neglected by gdp, such as: living a long and health life and being educated.

    • It is best included alongside DAI and gdp as an additional explanatory variable.


Other explanatory variables ctd1
Other explanatory variables ctd. Results From A Study of SETI@home

  • Country group dummy variables:

    • ITU’s “developed & advanced countries” versus ‘the rest’.

    • Alternatively: 6 regional dummy variables (similar to Caselli and Coleman II, 2001).

      See “Appendix: Country List”.


4 regression analysis
4. Results From A Study of SETI@homeRegression analysis

  • Matching data for 172 countries.

  • Dependent variables alternatively in 2004 levels and 2002-2004 changes.

  • Most regressions estimated in double-log form.

  • OLS with White’s heteroscedasticity correction.

  • Box-Cox regressions.


Regression results
Regression results Results From A Study of SETI@home


Regression results ctd
Regression results ctd. Results From A Study of SETI@home

  • Increasing DAI and gdp by 1% increases dependent variables by a similar %tage (elasticity of ‘change in results per capita’ with respect to DAI somewhat lower).

  • DAI, gdp, and the general divide between rich&poor countries can explain most of the cross-country variation in SETI@home participation and its intensity (see R2s).

  • HDI dropped from preferred regressions (DAI and HDI highly correlated).


5 the global seti@home digital divide
5. Results From A Study of SETI@homeThe global SETI@home digital divide

  • By Dec. 2004, developed & advanced countries (about 15% of the sample population) accounted for over 90% of submitted results.

  • But: Indications of a slowly narrowing global SETI@home digital divide!

    • Growth rates for ‘users’ and ‘results’ higher in ”the rest”.





6 concluding comments
6. Results From A Study of SETI@homeConcluding comments

  • Further research needed:

    • For a less heterogeneous group of countries. This would allow more sophisticated modelling.

    • More sophisticated models are needed to enable more specific policy conclusions.

  • Will non-commercial ‘social sharing’ via the Internet become a dominant mode of economic production?

    • There is huge potential for it, but commercial distributed computing might greatly affect its realization.