Experiment Date: 2/13/10
Start Time: 1:57:57
The aim of the experiment was to check the proper functioning of the mote and the pucks. The experiment was organized in such a way that the user performed a hand sanitizing event, walked into the room for approximately 15 seconds, came out and performed hand hygiene again, and waited again for 15 seconds before repeating the same.
The experiment was set up in a manner that the sanitizer when pressed would stimulate the puck and the readings were collected by the mote on the PC through the program PuckToRadio. The data was also recorded manually in order to keep track of the readings. Once the results were collected, the data generated by the mote was compared to the data obtained by the user.
Analysis:
For the first experiment using gel sanitizer, the data generated by the mote seemed to be in correlation with the data collected manually. A scatter plot was generated between the two data sets and the estimate was to see a linear trend in the experiment. Once the linear trendline was set up, the correlation constant (R ) turned out to be .9663 which indicated that the data sets generated by the mote and collected manually were in close proximity and followed a linear trend.
We calculated the difference between the two times generated by the Linux machine, of which the last five digits correspond to the milliseconds of the actual time. We divided the difference by 1000 to convert from milliseconds to seconds. We set up a relative point after which we calculated the difference between times recorded by us in seconds. The data for the same is shown in the table below.
For the second experiment using foam sanitizer, the data generated by the mote did not correspond to the manual data sets. The number of clicks recorded by the mote was lesser in number when compared to the ones recorded by us. The data set is linked below.
From results through the second experiment, we can hypothesize that the mote has problems sensing the signals when foam sanitizer is used. This may be due to the fact that the pucks do not respond in the same manner as they did when gel sanitizer was used. We noticed that the difference in seconds between two presses recorded by the mote differed by the sum of a few of our data points. This tells us that some data points have not been recorded by the mote. We could fix this by adjusting the physical set up of the puck to match the type of sanitizer being used, since we did not change the set up when switching from gel sanitizer to foam.
Deepti and Arunan
(links to come later tonight 2/18)
Great start. However, I think that Phil and I were looking for a slightly different analysis. I think the statistics you present measures the interarrival time of the pucks as a function of the interarrival time recoded by the experimenters. My guess is that the R^2 value is largely dependent on the accuracy of the experimenters — the differences between when the mote was actually pressed and the time the experimenters recorded by hand. What we are most interested in are false alarms and misses. To find this you need to set up a 2×2 grid for each experiment. The two columns should be labeled “Dispenser Pressed” and “Dispenser Not Pressed”. The two rows should be labeled “Puck Activated” and “Puck Not Activated”. Divide the time sequence into periods during which the protocol indicates a period during which the puck should have been activated (perhaps a 5 second period) and a period when it should not have been activated (perhaps a 15 second period). In experiment 1 we had 40 puck activations and 39 periods during which there was no puck activations. Go through the puck activation record and check for each interval whether or not there was a puck activation. If the puck was completely reliable, it should have 40 activations when we predicted activations and 39 intervals in which there were no activations. There should also be zero periods when we predicated and activation but saw none and no periods when we expected no activation but saw one anyway.
We should end up with a 2×2 matrix for each experiment.
Comment by gthomas — February 19, 2010 @ 11:42 am