Wireless Sensor and Actuator Networks for Lighting Energy ...

where x f (k) is the current upgraded fused value [79, 80].
4.4 Simulation and Experiment Results
The mote-FVF algorithm was tested with a small-scale sensor network
consisting of six mote sensors. The sensed target was the illuminance on the testbed
under the prototyping dimmable luminaire structure (see Chapter 7.4 for detail). The
MICA motes were integrated with the photosensor boards as shown in Figure 2-5(a) to
measure the illuminance. The test environment possessed the following characteristics:
• There could be a large change in illuminance, such as when lights are turned on
and off. Thus it is important to test the algorithm’s response to such a large
discontinuous change.
• The algorithm should be tested over the operating range of the lighting
environment – from 0 lux (completely dark) to 1000 lux (bright lighting
conditions in an indoor office).
• Although zero-valued states are usually considered to be an error or rest
condition for many systems, in the lighting environment zero can be either an
error or a meaningful state when the environment is completely dark. The
algorithm should be capable of distinguishing between them.
4.4.1 Hardware and Environment Setup
The illuminance on the testbed varied from 50 lux to 1000 lux in 18 equal
intervals, and the true illuminance was measured with a high fidelity light meter. Six
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