presentation of the STARS4ALL project for the Project networking workshop at the 6th AAAI Conference on Human Computation & Crowdsourcing (HCOMP 2018) - July 5th 2018, Zurich

1. Involving people in Citizen Science
through game incentives:
the case of the STARS4ALL project
on Light Pollution
Irene Celino, Gloria Re Calegari and Andrea Fiano
Cefriel – Politecnico di Milano

2. About the STARS4ALL project
Objective: fighting light pollution,
defending the “stars for all citizens”
right, encouraging citizens to care
and preserve European skies’
darkness
Consortium: 2 ICT (UPM, CEFRIEL),
1 Social Science (SOTON), 2
Economy (ECN, ESCP Europe), 1
Biodiversity (IGB-Berlin), 2
Astronomy (IAC, UCM) + a growing
set of external activists
http://www.stars4all.eu/

3. Fighting… what? Light pollution?
Transition to LED technology is good for energy saving but very dangerous in terms of light pollution!

4. Light pollution: should you really care?
Excessive light at night has a number of adverse effects:
 Diminished night sky visibility, because of light scattering
(i.e. you can’t see the stars anymore, especially from cities)
 Negative ripercussion on the circadian clock of higher vertebrates,
including humans (i.e. you don’t sleep well at night)
 Interference with life and reproduction of many species
(e.g. birds loosing their orientation while migrating because they
get confused by city lights)

5. Light pollution as seen from above
Astronauts on board of the
International Space Station (ISS) take a
lot of pictures as part of their activity
NASA makes all those pictures available
for free use online
Still we need to tell the pictures we
need (i.e. cities at night) apart from all
other photos
Italian astronaut Samantha Cristoforetti taking pictures
from the ISS windows during her space service

6. Stars and completely black images
(to calibrate light pollution measures)
Classifying ISS pictures
Cities at night
(primary objective)
Aurora borealis ISS Daylight or mixed

7. Night Knights www.nightknights.eu
 Game with a Purpose, i.e. pure gaming application that
“hides” a computational task
 Users play to achieve the game goals, but their actions
contribute to the solution of the ISS image classification issue
 Game mood related to astronauts, spaceship crew,
countdown to lift-off, space mission, etc.
 Multilingual Web application with responsive design to be
easily played on mobile devices

8. Night Knights gameplay www.nightknights.eu
Double-player mechanism with
1-minute game timer
Goal to pick the same category
for each picture
Gain points for agreements
 from agreements between
players we can derive the
pictures’ “true” classification
(cross-validation)

9. Night Knights incentives www.nightknights.eu
 Personal profile and
leaderboards (all time and
last 10 games best players)
 Badges for specific game
achievements
 Access to and download of
the most beautiful pictures
you played with

10. (Data Linking) GWAP Enabler
• Night Knights is just an example of a GWAP to solve a Data Linking problem
• Classification is a basic (and common) example of data linking
• The GWAP Enabler is a “white-label” version of the software behind Night Knights is
open source (Apache v2 license)
• A full end-to-end tutorial to use and customize the GWAP Enabler to create another
data linking GWAP is also available

11. Resources
Night Knights https://www.nightknights.eu/
Data from Night Knights http://ckan.stars4all.eu/dataset
GWAP Enabler https://github.com/STARS4ALL/gwap-enabler
Tutorial of GWAP Enabler https://github.com/STARS4ALL/gwap-enabler-tutorial
G. Re Calegari, A. Fiano and I. Celino: “A Framework to build Games with a Purpose for Linked Data Refinement”,
International Semantic Web Conference 2018, Resources Track, 2018
G. Re Calegari, G. Nasi and I. Celino: “Human Computation vs. Machine Learning: an Experimental Comparison for
Image Classification”, Human Computation Journal, vol. 5, issue 1, pp. 13-30, DOI: 10.15346/hc.v5i1.2, 2018

12. Thanks for your attention! www.stars4all.eu
Irene Celino – Cefriel – @iricelino – irene.celino@cefriel.com