Essay On Outlier

IV. GIVING MEANING TO UNUSUAL BEHAVIORS
After extracting outliers from semantic trajectories, the main goal of the next step is to add meaning to the outliers extracted. The next step is about splitting the outliers extracted to tree types according to their speed: Stop outlier, regular/slow outlier, Fast outlier, figure 4 illustrates the classification of outliers extracted.
A. A stop outlier
It occurs when the moving object made a stop for some time during the deviation, for instance the moving object had an appointment, a meeting, go shopping after work, pick up the children at school, go with friends, pass by a market, or something to do somewhere else that was not in the standard path. This is an intentional detour with a reason. To discover if an outlier has a stop we need to look for stops not in the complete outlier trajectory, but only in the sub-trajectory that corresponds to the outlier (deviation), i.e., the outlier segment. We consider as a stop a sub-trajectory that its speed is close to zero for a minimal amount of time (MT).
B. A regular/slow outlier
It occurs when the moving object deviates from the main route without changing its speed, or with a degradation of speed. This may reveal that

For that we look for slow traffic in the main route at the time of the outlier. To measure the speed on the main route at the same moment that the outlier deviated from it we need to look only at the segments of the synchronized common trajectories. The average speed of all synchronized common segments in the same main route is compared to the speed of the non-synchronized common segments in the same route. We consider that there is a traffic jam when the average speed of those who are synchronized is less than half of the average speed of the