Information Technology Reference
In-Depth Information
The top-floor of the Innotek building houses some laboratories where people
have to be present to follow up experiments. These spaces also show occupancy
at night, during weekends and in holidays.
The occupancy data is captured by centrally mounted high-quality PIR-based
sensors that are part of the Philips system to install the automatic lighting.
Detection of motion will trigger the lights which will remain switched on for at
least 10 minutes. If no motion has been detected in this period, the lights will
turn-off again. Innotek has arranged for connecting these sensors to the bus of
their Johnson Controls heating management system, which enables their use to
control the room temperature also. The climate management system will set the
room to ”hibernation mode” if no occupancy has been detected for a certain time
interval. Once occupancy is detected, the room climate will go to the comfort
level as set locally per room by the inhabitants. New oce buildings in Flanders
will have to meet smart building controls like this in the very near future.
As the Johnson Controls sensor bus can be read out at a central point we have
been able to log the data of most rooms of the building on a 1 minute accurate
timescale. The events are based on integration of detections over the 1 minute
interval and indicate the occupancy with a high level of confidence.
The plans of the three floors of the Innotek building are shown in figure 2.
We worked on the logs of the Innotek dataset related to the period from March
12 2010 to August 28 2010. The log file follows this structure:
1. 00101031261337
2. 00111031261433
3. 00101031261448
4. 0011103126155
5. ...
The first line means that sensor 1 of floor 0 provides no occupancy information (0
at third column) the day 12 of march 2010, which has a type day of 6 (meaning
it was Friday) at the time 13:37. In the second line, the same sensor provides
occupancy information (value 1 at third column) at time 14:33, line three shows
that the room was empty again at time 14:48 and so on.
With this information (only binary occupancy with 1 minute frequency) we
construct the documents, one document for each room and day, which are se-
quences of words over 30 minutes interval. The frequency patterns can be seen
more clear in a video, which plots the obtained frequencies on the building
ground-plane, posted online at http://fcastanedo.com/wp-content/uploads/
2010/11/foo-candidate-30min.avi .
A document is formed using the frequency of words which composed them,
following an approach similar to tf-idf [14] scheme. Therefore the original data
is transformed on another which follows this structure:
1. 9 0:34 8:4 16:10 24:10 32:16 40:16 48:10 56:10 64:16
2. 23 0:34 8:4 16:2 17:2 18:1 19:1 20:1 23:3 31:10 39:16 40:7 41:1 43:1 44:1 46:1
47:5 50:1 52:1 53:1 54:1 55:6 56:10 64:16
3. ...
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