Wireless Sensor and Actuator Networks for Lighting Energy ...

Current Level on the investigator’s GUI in Figure 8-4 (b), but was left out on purpose to
avoid possible biases when evaluating the performances of the systems.
System performance comparison
The questions asked in the questionnaire regarding the performance of both
systems were: (1) whether the participants felt comfortable working under the lighting
systems, (2) whether the systems successfully maintained the lighting chosen by the
participants, and (3) if the two systems performed differently on the subjects. As
pointed out previously, other than the types of overriding mechanisms, the subjects
were not told how many different lighting systems they were exposed to or what
systems the overriding mechanisms controlled. The first question was quantified using a
five-level scale: totally agree, partially agree, neither agree nor disagree, partially
disagree, and totally disagree. The second question was answered using a 1-7 scale
where 1 means poor performance and 7 means excellent performance. Table 8-3
summarizes the answers to the first two questions gathered from the questionnaires.
Answers of totally agree and partially agree to the first question are assigned to the
same category in Table 8-3, as are those of totally disagree and partially disagree. For
the second question, answers below 3 and above 5 are considered bad performance and
good performance respectively in Table 8-3. Detailed responses from the subjects are
tabulated in Appendix B.3.
According to Table 8-3, it is fair to say that both systems delivered a
comfortable lighting environment and managed to maintain the light at the levels of the
subjects’ choices. One subject did not rate the ability of the commercial system to
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