Texas Advanced Computing Center - Visualization

VAST 2008 Challenge
Mini Challenge 4:  Evacuation Traces

Authors and Affiliations:

Jaya Sreevalsan-Nair, Texas Advanced Computing Center, jaya@tacc.utexas.edu  [PRIMARY contact]
Weijia Xu, Texas Advanced Computing Center

Student team: NO

Tool(s):

We developed our own visualization tool using OpenGL and C++ in July 2008 for purposes of analyzing data for this contest. This simple tool allows one to do animation of the data by drawing traces of each person as a line of specific color (in order to distinguish between different persons). This tool enables the user to move forward and backwards in time which enables them to study the evolution of events leading to and after the explosive detonation in the building. It also provides facility to look at one or all persons at a time, which is very helpful in identifying the actions of specific persons during the event.

Two Page Summary:   YES

    Traces-summary.pdf

ANSWERS:

Traces-1  Where was the device set off?

Short Answer:
Grid cell number of where the device went off: 66 x 32
Around timestep 370-374, a lot of people on the left side of the building start to move which continues to being evacuation traces.
At that instant, we observed there are upto 6 casualities in the right side of the building soon after this timestep. RFIDs 18, 50, 76, 56, 19 and 1, who are close to each other, stop movements are at timesteps 383, 384, 403, 413, 439 and 463, respectively. Since RFIDs 18 and 50 are the first ones to be casualities and they happen to be in the same room, the likelihood of the device being in that room is very high.

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

Short Answer: 
List of RFID tag numbers :  28; 40; 59; 64; 76; 77; 78; 1; 13; 21; 36; 39; 56
28 moves to the opposite end of the safe room inside the building. 21 is the only one who enters the room where the device is detonated. 21 and 1 show suspicious behavior at a close distance and enter an enclosure in the building without evacuating. 76 is very close to the room with the device, and 56 moves towards the direction of the explosion and combats 76. 78 and 39 have a suspicious interaction after which they both stop movements. 36 moves before the device detonates only for once in the entire period, indicating he has thrown his badge away to escape detection. 13 follows 56 for a distance and retreats once 56 stops movement, thus 13 is a suspect and 56, a witness. 64, 40 and 77 are possible witnesses since they were in the same room as 13 and 56 initially and they moved together.

Traces-3  Identify any suspects and/or witnesses who managed to escape the building.

Short Answer: 
List of RFID tag numbers :  40; 64; 77; 13; 36
From the list of possible suspects and witnesses, these RFIDs (except for 36) made it to the exits in the front of the building. Possibly 28 made it safe to the enclosure at the back of the building. 36 goes unnoticed through the entire period. Hence there is a possibility that 36 made it to the exit as well. 

Traces-4  Identify any casualties.

Short Answer:
List of RFID tag numbers : 1; 18; 19; 21; 39; 47; 50; 56; 59; 60; 65; 69; 76 ;78
All these RFIDs stop movements and end up in the interior of the building and are unable to move to the  exits or the safety spot.  18, 50 and 19, in the vicinity of the device, stop movements immediately after the detonation. 56 and 76  stop after coming  in contact with each other, which indicates they attacked each other, especially with 56 moving towards the detonation spot. Similar event occur between 39 and 78.  21 and  1  stop movements in an  enclosure,  after changing their route to the exit; which indicates they are injured.  56 stops very close to the exit after  13 follows him, which shows a high probability of attack.  47, 59, 60, 65 and 69 stop very close to the  safe spot in the back of the building, which indicates  they have been injured while trying to exit either by the fumes of the detonation or by stampede, since there seems to be no other foul play.

Traces-5  Describe the evacuation

Detailed Answer:
The people in the building follow the natural rule of running out to nearest exit. It is very clear from the paths taken soon after the detonation. All the people at the back try to reach the safe enclosure in the back of the building. There is a heavy flow of people in the left-side of the building which confirms that the device was detonated in the right side, and there are more casualities in the right side. We observe there are 3 exits in the front of the building. There is presumably a safe spot in the back of the building where a lot of people concentrate. The breakdown of the people making it safe are: 29% at the leftmost exit, 32% at the center exit, 6% in the rightmost exit, 12% in the back, and 19% in the interior of the building.
Shown below is the general pattern observed from the paths.

 Figure 1: Building map: The black dots indicate solid structure, the grey lines indicate the possible paths all the 82 persons took in 837 time-steps, the red arrows
indicate the general evacuation patterns most people followed and the blue dot indicates possible spot of detonation, 'Exit' implies exit from the building,
'Safe' is a spot a few people went to during evacuation.

There are strange anomalies that can be seen during the evacuation. Though the casualities due to the actual impact of the device are very few: RFID's 1, 19, 21, 18, 50, 56 and 76. However there are suspicious interactions that we observed that led us to believe the cases of suspects and witnesses.

• RFID 28 moves a lot in the beginning as well, and eventually moves towards the safe spot, stays away from the crowd in the other end of the enclosure and at time=591 he stops moving. It is highly improbable he is injured. He is more likely a witness than a suspect because if he were a suspect, he will move with the crowd to avoid detection and if he were not a witness, he would still have moved with the crowd as a natural behavior.
• RFID 21 is clearly the one who planted the device from our hypothesis. However soon after the detonation the dynamics between RFIDs 28 and 1, who was in the adjacent room of the detonation, is strange. RFID 28 moves away from the detonation, but moves into another enclosure after following 1. 1 stops moving at timestep 479, indicating that he has been impacted by the explosion by virtue of vicinity. However, 21 and 1 never come in touch in the enclosure, 21 entering much after 1 stops moving. 21 eventually stops moving at timestep 520. Our hypothesis for this is that 1 and 21 are accomplices and they are both injured and are hence casualities themselves.
• RFID 56 is a possible suspect. He moves around a lot in the beginning and after the bomb detonates, he walks in the direction of the device rather than away from it. He tries to come in contact with RFID 76 who is in the adjacent room where the device is set off. Soon after their contact, 76 stops moving, and 56 stops moving after a little while. We hypothesize that 76 is likely a witness since 21 visits his room before planting the device in the neighboring room. 56 attacks 76 to protect 21. However due to proximity of 76 to the explosion, 76 is likely very injured already. 56 becomes a casuality either by inhaling poisonous fumes from the explosion or in a rare event, 76 attacks him back.
• RFID 19 accidentally moves towards the scene of explosion and becomes the casuality, very probably due to the poisonous fumes from the explosion.
• RFID 36 moves only once during the entire time-period. His movement occurs much before the device detonates at timestep 243, which implies that he is very unlikely a casuality. It brings us to believe that he is a suspect and has thrown away his RFID badge to avoid detection.
  
• RFIDs 59, 64, 40, 77 are possible witnesses, whereas RFID 13 is a possible suspect, who meets with RFID 44 at timestep 198. 59 is later followed by 13 during which 59 stops movement at timestep 689, possibly is attacked by 13, while the others escape.
• RFID 39 meets with RFID 78 at timestep 513 and then retraces his path and moves around in a closed corridor until timestep 573. 78 moves last at timestep 619 and 39 moves last at timestep 653. Their movements prior to their meeting indicate evacuation. However the pattern changes after they meet. Possibly there has been an attack between the two at the meeting point, and both get seriously injured. Their injuries are not induced by the  device because they are at a safe distance from the device at the time of trigger. It is very likely that 39 is a suspect, as he moves in the direction opposite to the rest of the occupants of the room he is in. That leads us to believe that somehow 78 is a witness.
  

Figure 2: Closeup of the Detonation spot

Hence we conclude that that RFIDs trapped in the interior of the building except for RFID 36 are all casualities. RFIDs 28, 40, 59, 64, 76, 77 and 78 are possible witnesses. RFIDs 1, 13, 21, 36, 39, and 56 are possibly the perpetrators.