Crowd Flow Model Development for Consequence Assessments

Capstone Proposal:
Development of a Crowd Flow
Model Coupled with
Concentration Fields for
Consequence Assessments
John Bambrick
Advisor: Frank Hardisty
1
Outline
What is Consequence Assessments
Models for Coupling
Proposed Model Development
Case Study
Journal Article
2
WHAT IS CONSEQUENCE
ASSESSMENTS (CA)?
 
3
Analysis of Risk/Threat from
Hazardous Atmospheric Releases
2002 Accidental Release of Chlorine Gas from a Railcar in Festus, MO.
http://www.aristatek.com/Newsletter/OCT07/OCT07ts.aspx
4
MODELS FOR COUPLING
 
5
 CA Models
HPAC
Is commonly used by civil
government and military
Couples hazard plume
with static population
dataset for casualty
estimate
Has potential for over
prediction of casualties
6
Crowd Flow Models 
(2 Categories)
Microscopic
Simulates individuals
Discrete position
Computationally “heavy”
Applied within EpiSimS
Macroscopic
Models density flow
1D and 2D cellular
Computationally “light”
Applied within ???
Simulated Individuals Moving Around an Obstacle
http://www.cs.virginia.edu/~gfx/pubs/group_behaviors_2/jar_herd.pdf
Cellar Flow of Density
http://scholar.lib.vt.edu/theses/available/etd-12152006-143454/unrestricted/NewCM.pdf
7
PROPOSED MODEL DEVELOPMENT
 
8
Proposal
Develop a prototype macroscopic crowd flow
model coupled with CA outputs to predict
casualty estimates
Develop a 2D pedestrian flow model
Develop for specific scenario
Build in ArcGIS 9.3 with VBA
Couple HPAC outputs with 2D flow model
Document in journal submission
9
Concepts Behind Model
 
http://www.timtim.com/drawing/vie
w/drawing_id/398
http://www.theipinionsjournal.com/index.php/2006/07/its-official-second-hand-
smoke-kills/
Running with the Bulls
http://www.flickr.com/photos/mcmahon/4788415049/
10
Key Components
Concentration Fields
From HPAC
Environment
Crowd
Obstacles
Terrain
Egresses
Crowd Flow Model
11
Key Functions
Dosage calculation
Dosage = ∑ Concentration × Time Step
Crowd flow model
Primary flow driver
Recognize hazard
Determine directional flow based on hazard
Unique for differing hazard types
Secondary flow drivers
Model crowd density
Find path of least resistance
Find egress for escape from hazardous environment
Selection between primary and secondary flow factors
12
Moved out
Moved in
Stayed in
Quasi-Macroscopic
True Macroscopic
Model density flow
Know density but not who went
where
No way to know who got what
exposure
Quasi-Macroscopic
Model “individual” in flow
Track who went where
Track exposure of each
“individual”
ρ
=7
ρ
=4
ρ
=2
ρ
=9
ρ
=5
ρ
=5
ρ
=3
ρ
=2
ρ
=3
ρ
=3
ρ
=5
ρ
=6
ρ
=4
ρ
=6
ρ
=4
ρ
=3
ρ
=2
ρ
=2
Concentrations
T
1
T
2
T
1
T
2
13
Primary vs. Secondary Flow Direction
Flow Rate
Fast
Slow
Primary
Primary
Secondary
Primary
Secondary
Hazard
Primary Only
Secondary Only
Split Primary and
Secondary
14
T
1
T
2
Data
Population shapefile
Point geometry
Attributes
Characteristics
Status
Variables
Concentration fields & aspect
Source: HPAC
Point geometry interpolated to raster
Environmental rasters
Density & aspect, slope
Distance from obstacles & aspect of slope
Terrain
15
Crowd Flow Model
Flow Direction
Population Data
Population
Density
Primary Flow:
Hazard Induced
Flow Direction
Secondary Flow:
Path of Least
Resistance
Concentration Field /
Flow Driver
Integrated
Exposure
People
Rate
Urgency:
Hazard Induced
HPAC
User:
Study Area
Definitions
Environment
Location,
t
n-1
, t
n
Data Flow
16
Variable Sources for Primary and
Secondary Flow (Conceptual)
Primary direction
Aspect (downward direction) of concentration
Secondary direction
Aspect of density (weighted by slope)
Perpendicular to aspect of the slope of distance to the
obstacle (weighted by inverse of distance)
Rate
Urgency
Function of concentration above detectable levels but limited to
individual’s max speed
Resistance
Function of density
Friction factor classified by terrain
17
Constants
Time Step Sequence
Pop
X,Y
t
n-1
Population
Density
Aspect
Conc.
Field
HPAC
Aspect
IDW
Kernel
Density
Slope
Slope
Aspect
Aspect
Pop
X,Y
t
n
Conc.
Field
IDW
Obstacles
Terrain
Output
t
n-1
Output t
n
Reclassify
Friction
Factor
Distance
Distance
Flow
 
Direction
Calculation
Rate Calculation
Aspect
Aspect
Time
Step
Intake
Extract from Raster at Point
Internal Calculation
Geoprocess
Point Data
Raster
Flow
Vector
T
n-1
T
n
<<dependant on>>
18
Development Priorities
Calculation of individual’s intakes from concentration fields
at T
n
 location (
Required
)
Create individual’s primary flow vector at T
n 
and new
location  (
Required
)
Create secondary flow direction based on density and
selection algorithm (
Required
)
Create secondary flow direction based on obstacle
avoidance and selection algorithm (
Optional - probable
)
Apply terrain based friction factors to flow rate (
Optional –
possible
)
Create secondary flow direction toward egresses and
selection algorithm (
Optional - doubtful
)
19
CASE STUDY
 
20
Case Study
Accident results in Cl
2
 released near pedestrian mall
Cl
2
Visible and odorous
Irritation and harmful effects
Cl
2
 acts as primary flow driver (crowd responds)
Flow from high to low concentrations
Urgency determined by concentration level
21
Expected Results
Dosage developing over time
Casualty estimates provided
Results comparatively different from a static
population
Each run of model unique
Exploration of scale adaptability
22
JOURNAL ARTICLE
 
23
Article Submission
Purpose:  To propose and promote the use of dynamic
population flow models in consequence assessments
Contents
Present concepts of model
Demonstrate the working conceptual model
Suggest uses
Identify areas for future development
Candidate journals
Risk Management
Journal of Homeland Security
Journal of Homeland Security and Emergency
Management
24
QUESTIONS?
 
25
Slide Note
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Development of a crowd flow model coupled with concentration fields for consequence assessments. The proposed model aims to predict casualty estimates by integrating pedestrian flow and hazardous atmospheric releases. Various existing models like EpiSimS, HPAC, ALOHA, and CATS are considered in the development process. The study involves microscopic and macroscopic crowd flow models, scenario-specific development in ArcGIS, and journal submission documenting the findings.


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  1. Capstone Proposal: Development of a Crowd Flow Model Coupled with Concentration Fields for Consequence Assessments John Bambrick Advisor: Frank Hardisty 1

  2. Outline What is Consequence Assessments Models for Coupling Proposed Model Development Case Study Journal Article 2

  3. WHAT IS CONSEQUENCE ASSESSMENTS (CA)? 3

  4. Analysis of Risk/Threat from Hazardous Atmospheric Releases 2002 Accidental Release of Chlorine Gas from a Railcar in Festus, MO. http://www.aristatek.com/Newsletter/OCT07/OCT07ts.aspx 4

  5. MODELS FOR COUPLING 5

  6. CA Models EpiSimS HPAC ALOHA ALOHA CATS CATS QUIC QUIC HPAC Is commonly used by civil government and military Couples hazard plume with static population dataset for casualty estimate Has potential for over prediction of casualties 6

  7. Crowd Flow Models (2 Categories) Microscopic Simulates individuals Discrete position Computationally heavy Applied within EpiSimS Macroscopic Models density flow 1D and 2D cellular Computationally light Applied within ??? Simulated Individuals Moving Around an Obstacle http://www.cs.virginia.edu/~gfx/pubs/group_behaviors_2/jar_herd.pdf Cellar Flow of Density http://scholar.lib.vt.edu/theses/available/etd-12152006-143454/unrestricted/NewCM.pdf 7

  8. PROPOSED MODEL DEVELOPMENT 8

  9. Proposal Develop a prototype macroscopic crowd flow model coupled with CA outputs to predict casualty estimates Develop a 2D pedestrian flow model Develop for specific scenario Build in ArcGIS 9.3 with VBA Couple HPAC outputs with 2D flow model Document in journal submission 9

  10. Concepts Behind Model http://www.timtim.com/drawing/vie w/drawing_id/398 Running with the Bulls http://www.flickr.com/photos/mcmahon/4788415049/ http://www.theipinionsjournal.com/index.php/2006/07/its-official-second-hand- smoke-kills/ 10

  11. Key Components Concentration Fields From HPAC Environment Crowd Obstacles Terrain Egresses Crowd Flow Model 11

  12. Key Functions Dosage calculation Dosage = Concentration Time Step Crowd flow model Primary flow driver Recognize hazard Determine directional flow based on hazard Unique for differing hazard types Secondary flow drivers Model crowd density Find path of least resistance Find egress for escape from hazardous environment Selection between primary and secondary flow factors 12

  13. Quasi-Macroscopic True Macroscopic Quasi-Macroscopic T1 T2 T1 T2 =9 =3 =5 =6 =5 =5 =2 =7 =4 =4 =6 =4 =3 =2 =3 =3 =2 =2 Moved out Moved in Stayed in Concentrations Model density flow Know density but not who went where No way to know who got what exposure Model individual in flow Track who went where Track exposure of each individual 13

  14. Primary vs. Secondary Flow Direction Hazard T1 Fast Flow Rate Primary Slow Split Primary and Secondary Primary Only Secondary Only Secondary Secondary T2 Primary Primary 14

  15. Data Population shapefile Point geometry Attributes Characteristics Status Variables Concentration fields & aspect Source: HPAC Point geometry interpolated to raster Environmental rasters Density & aspect, slope Distance from obstacles & aspect of slope Terrain 15

  16. Data Flow Input User: Study Area Definitions Output Crowd Flow Model Population Data Location, tn-1, tn Integrated Exposure Environment Population Density People Rate Flow Direction Secondary Flow: Path of Least Resistance Primary Flow: Hazard Induced Flow Direction Urgency: Hazard Induced Concentration Field / Flow Driver HPAC 16

  17. Variable Sources for Primary and Secondary Flow (Conceptual) Primary direction Aspect (downward direction) of concentration Secondary direction Aspect of density (weighted by slope) Perpendicular to aspect of the slope of distance to the obstacle (weighted by inverse of distance) Rate Urgency Function of concentration above detectable levels but limited to individual s max speed Resistance Function of density Friction factor classified by terrain 17

  18. Time Step Sequence Tn-1 Tn Slope Slope FlowDirection Calculation Flow Vector Pop X,Y tn-1 Population Density Kernel Density Aspect Aspect Pop X,Y tn Time Step Intake Rate Calculation Output tn-1 Conc. Field Aspect IDW Aspect HPAC Conc. Field IDW Output tn Constants Distance Aspect Point Data Obstacles Aspect Distance Raster Geoprocess Friction Factor Terrain Reclassify Extract from Raster at Point Internal Calculation 18

  19. Development Priorities Calculation of individual s intakes from concentration fields at Tn location (Required) Create individual s primary flow vector at Tn and new location (Required) Create secondary flow direction based on density and selection algorithm (Required) Create secondary flow direction based on obstacle avoidance and selection algorithm (Optional - probable) Apply terrain based friction factors to flow rate (Optional possible) Create secondary flow direction toward egresses and selection algorithm (Optional - doubtful) 19

  20. CASE STUDY 20

  21. Case Study Accident results in Cl2 released near pedestrian mall Cl2 Visible and odorous Irritation and harmful effects Cl2 acts as primary flow driver (crowd responds) Flow from high to low concentrations Urgency determined by concentration level 21

  22. Expected Results Dosage developing over time Casualty estimates provided Results comparatively different from a static population Each run of model unique Exploration of scale adaptability 22

  23. JOURNAL ARTICLE 23

  24. Article Submission Purpose: To propose and promote the use of dynamic population flow models in consequence assessments Contents Present concepts of model Demonstrate the working conceptual model Suggest uses Identify areas for future development Candidate journals Risk Management Journal of Homeland Security Journal of Homeland Security and Emergency Management 24

  25. QUESTIONS? 25

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