Data Analysis
The data analysis software reads the data from the data files that the data acquisition system produced and compiles some interesting graphs describing the motion of the fly.
Position
This category simply finds plots all the positions that the fly travels. Since the data is processed and updated in real-time, the graph look like the sped up motion of the flies with everywhere it has gone recorded. There is little processing for this category since the data comes in as these positions, but the graph is scaled and the values converted from pixels to an input length unit using the coordinate data. This way the user will see all flies in relative same scale and know the extent that it has moved in its environment. While this graph will show the user where the fly has moved, it will not be very useful for comparisons after long recording periods when the flies have moved to most of the positions in the tray and any new movement can not be seen by the user. Other categories become necessary to characterize the fly’s motion.
The following categories all have the same three subcategories for each: function of time, Histogram, and Fast Fourier Transform. Since the data is updated in real-time, a plot of each of the characteristics as a function of time was displayed to show its variation with time. The histogram is used to give the user an idea of the distribution of that data. The Fast Fourier Transform breaks each signal down into functions of sine and displays the intensity of each frequency. This is used to determine if the flies have any particular pattern to how they cycle between activity and inactivity. This subcategory also requires a long recording period to see multiple cycles before any useful information can be seen.
The Categories used to characterize the flies are activity counts which have radial and line count categories, and velocity which has speed, radial velocity, and angular velocity categories.
Activity Count
This category is used to quantify how active the flies are for each discrete amount of time. Since the previous DAM system also recorded the fly activity by this criterion, it also serves to confirm previous results under the DAM system. The line count is the most similar to the previous system as it counts how many times the fly crossed a line it arbitrates across the diameter of the dish. The radial count is to be used as an improvement over the previous system in accuracy and control. It counts how many times the fly will move a beyond an input threshold distance away from its previous position. This takes advantage of the greater precision of the new system and allows users to define how great a movement is to be considered activity.
Velocity
We also wanted to quantify the intensity of the fly’s activity. To do this we decide to calculate the fly’s velocity. We first simply calculated the speed of the flies to see what magnitude was their rate of motion. Later, we decided to find the radial and angular velocity of the flies with the origin set at the center of each dish. With these polar components of velocity, we can see the tendencies of flies to move in circular paths around the perimeter of the dish versus tendencies to move across the dish. Researchers believe that such activity or inactivity may correlate to fly’s tendency to explore and its implications about their locomotive activity.