Figure 1.
Noise sample screen for WideNoise Plus mobile application.
Figure 2.
Perception screen for WideNoise Plus mobile application.
Figure 3.
Tag screen for WideNoise Plus mobile application.
Figure 4.
Map screen for WideNoise Plus mobile application.
Figure 5.
Number of measurements collected each day from Dec. 8th 2011 till Jun. 6th 2013. The labels correspond to: (1) case study in Rome (9th June 2012); (2) launch of the Heathrow activities (19th June 2012); (3) Antwerp test case (10th July 2012); (4) Birmingham workshop (5th October 2012); (5) article in German regional newspaper (published 29th April 2013, activity peak on the 30th of April 2013). In the inset an enlarged view of event 5 is showed. The decay of user participation is consistent with a power-law of exponent (red curve).
Figure 6.
Scatter plot of the number of measurements collected each day compared to the number of active devices at that day. The dark green symbols correspond to the most important spikes shown also in Figure 5. The green and blue lines are guides for the eye and correspond to the case of one measure per device and two measures per device respectively.
Figure 7.
Power-law compatible distribution of the number of measurements performed by each user. The red dashed line corresponds to a powerlaw of exponent −2.5.
Figure 8.
Worldwide sample density, including all measurements, illustrated as a heatmap (© OpenStreetMap contributors for map data, used and redistributed under the CC-BY-SA licence[26]).
Table 1.
General space and time coverage.
Figure 9.
Worldwide sample density, including only measurements with attached perceptions, illustrated as a heatmap (© OpenStreetMap contributors for map data, used and redistributed under the CC-BY-SA licence[26]).
Figure 10.
Worldwide sample density, including only measurements with attached tags, illustrated as a heatmap (© OpenStreetMap contributors for map data, used and redistributed under the CC-BY-SA licence[26]).
Figure 11.
Estimated versus measured noise.
Each point corresponds to one measurement, while both the colour scale light to dark grey and the point size represent the user expertise (small to large amount of previous measurements).
Figure 12.
Difference between estimated and real dB value vs the number of measurements a user has performed.
Figure 13.
Distribution of measured noise levels.
The plot shows the histogram of noise levels for the first measurements performed by users, compared to those performed after some experience is gained (after the 50th measurement).
Figure 14.
Tagged measurements for different expertise levels.
The cumulative number of users submitting at least measurements is displayed in blue (left axis legend), while the red points represent the average number of tags used in the
-th users' measurement (right axis legend).
Figure 15.
Perception evaluation versus the measured noise level.
The red lines display the average evaluation over the first five measurements of all users; the green lines correspond to the average evaluation over the set of all measures taken by users starting from the 50th one.