University of Bari – IVU lab
Mini Challenge 4: Evacuation Traces
Authors and Affiliations:
Simeone, University of Bari, firstname.lastname@example.org
Paolo Buono, University of Bari, email@example.com
We specifically developed a tool in WPF (Windows Presentation Foundation) for the purpose of visualizing and interpreting the data of the challenge. It was developed at the IVU Lab of the University of Bari in these last months. In our tool, there are two main visualization modes. In the first, an animation of each person’s movement during the recorded time is displayed. Each person is represented as a green dot that moves across the map. Users can interact with the animation by pausing and resuming it, advancing or rewinding it frame by frame. Since it is impossible to distinguish a particular person from its green dot representation, we allowed users to “highlight” one or more persons by clicking on them. Once highlighted, a light cyan transparent circle will be displayed and will follow the person as it moves around the map. In the second visualization method, instead of showing the actual animation, we use the movement data to trace a line that represent their path during the course of the animation. Users can customize this visualization by choosing the starting and ending point (in terms of keyframes) of their path. The rightmost portion of the bottom control panel, allows the user to “place” the bomb. They can select the radius, and then click on the map to place a red transparent circle. Finally the right side panel allows the user to filter (or restore) uninteresting persons, by rendering them in a light gray color or removing their path tracks (if in the tracking mode).
Two Page Summary: YES
Grid cell number of where the device went off:
X: 66, Y: 34
People that used our tool were asked to use the “place bomb” feature of the tool, so that they could mark the exact location of the explosion by a red circle (with a customizable radius). The majority of the users (53.84%) marked a point inside the room where number 18 and number 50 are (Figure 1). Therefore we chose the center of that room as our final answer (Figure 2). According to the users, the main suspect either “throws” the device inside that room or activates it upon entering that room.
Figure 1 - The red dots mark the locations of the detonation chosen by our users. Some of the locations are overlapped.
Figure 2 - The supposed location of the bomb (X:66 Y:34) and its possible area of effect
Traces-2 Identify potential suspects
and/or witnesses to the event.
Note: Potential suspects and/or witnesses are people who were near the area just prior to the explosion and exhibit suspicious behavior
List of RFID tag numbers :
Suspects: 21, 28, 29
Witnesses: 1, 18, 50
According to our users’ answers, Number 21, Ramon Katalanow is the most probable person to have detonated the bomb. It was chosen as the main culprit by 76,92% of the interviewed. Most users arrived at this answer by looking at the animation, noticing where the probable area of detonation was and examining the people in that area. Thanks to the “highlight” feature, most of them concluded that nr 21 was probably the terrorist, due to his suspicious behavior. When asked to indicate other potential suspects, number 28 and 29 were equally chosen by 30,77% of the interviewed. The most probable eye witnesses that saw nr. 21, are number 1 (chosen by 60% of those users that chose nr. 21) , number 18 (50%) and number 50 (40%). They were chosen because the users stated that number 21 was in their line of sight (Figure 3).
Figure 3 - On the left image, Nr. 21 (in red) enters the room and he is probably seen by Nr. 18 and Nr. 50 (in green). On the right image, Nr.21 could also have been seen by Nr. 1 on his way outside the building.
Traces-3 Identify any suspects and/or witnesses who managed to escape the building.
List of RFID tag numbers :
Persons who managed to escape: 1, 21, 28, 29
A person is considered “escaped” from the building if he/she manages to reach one of the three wide rectangular areas on the borders of the map. All of the interviewed correctly found out if the suspect or witness that they chose managed or not to escape the building by seeing where they were located at the end of the animation. In Figure 4, the image shows which persons managed to escape among those our users marked as potential suspects or witnesses.
Figure 4 - The persons who managed to escape (that were among the suspects or witnesses) are highlighted in their final location in the three "safe zones"
Traces-4 Identify any casualties.
List of RFID tag numbers :
18, 19, 36, 39, 47, 50, 56, 60, 65, 69, 76, 78
The largest “casualty group” identified by our users is the one reported above and it was chosen by 53,84% of them. They decided if they had to be considered as a casualty whether or not they were moving after the explosion. We identified two groups of casualties, a bottom one (Nr: 18, 19, 36, 50, 56, 76) and a top one (39, 47, 60, 65, 69, 78). The bottom one (bright red in Figure 5) are the most probable casualties because they stop moving few frames after the possible explosion, around frame 410 (while the explosion occurs at frame 370). The second group (darker red in Figure 5) stops moving at frame 625. A possible anomaly is Nr 59, described in the next section
Figure 5 - The two groups of casualties: the bottom one are those that have the highest chances to be counted as casualties. The top group are probably also casualties. We were unable to determine if the highlighted person in the bottom of the screen, nr. 59, is also a possible casualty.
Traces-5 Describe the evacuation
A complete understanding of how the evacuation developed could be comprehended by showing in a visual manner the movement of each person on the map (also see the video we provided). One of the file at our disposal in fact contains the exact location of every person for each of the moments in which data was recorded (about 820 “ticks”). By using the coordinates of each person as a keyframe, it is possible to obtain a fluid animation by interpolating the coordinate between each frame. In this way users can see exactly how the evacuation develops by being on both large and individual scale. They are in fact able to monitor each person’s path, thanks to the “highlight” feature (that places a light cyan transparent circle around the “focused” person, enabling the user to follow him/her around). By looking several times at the animation, they realized that the explosion occurs around frame 370 approximately in the northeastern quadrant. Before that time, the employees move very little. In fact by using the “show traces” feature (displayed in Figure 6), and then clicking the button to filter out nonmoving persons, we are able to know that only 4 persons move before the bomb is detonated, and our primary suspect, Nr. 21, is among them. Assuming that “moving before the bomb detonates” is a suspicious behavior, this could lead to narrowing down the list of suspects. Failing that, examining the area of the incident is also a good way to start the investigation.
Figure 6 - The only four persons that move before the bomb detonates, after having applied the automated filter – the green dot is their starting point, while the red dot is their ending point (at the frame selected in the sliders in the bottom part of the interface)
Around frame 370, everyone starts to flee in a somewhat orderly fashion towards their nearest exits. We do not know if this moment in time marks the time of detonation or the time when the alarm starts to ring. In fact, it can be observed that as soon as everyone starts to move, the “future” victims are still moving: they will cease to move several frames later. As previously mentioned (and reported in Figure 5), the “bottom” group of the persons we marked as casualties stops moving at frame 425, while the other group stops moving at frame 610, but we are unable to determine if this second group is composed of persons standing still or possible casualties. The only anomaly in the evacuation that we and our users noticed is that Nr. 59 first tries to reach for the exit, then when she (Olive Palmer) is almost out of the building, she retraces her steps perhaps towards the other exit. At this point she is followed by Nr. 13. At a certain point Nr. 59 stops and as soon as she does that, Nr. 13 goes back towards the exit. Could this mean that N. 13 follows Nr. 59 to kill her? We are unable to determine this.
At the time of the last frame of the animation, the only persons inside the building are the two “casualty groups” identified in the previous answer, and nr. 59.