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© 2005 Philippe A. Bonnefoy, Roland E. Weibel, Engineering
Systems Division, Massachusetts Institute of Technology 1
Air Transportation System Air Transportation System Architecture
AnalysisArchitecture Analysis
Project Phase IIProject Phase II
Advanced System ArchitectureAdvanced System Architecture
Spring 2006Spring 2006
March 23rd, 2006
Presentation by: Philippe Bonnefoy
Roland Weibel
Instructors: Chris Magee, Joel Moses and Daniel Whitney
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© 2005 Philippe A. Bonnefoy, Roland E. Weibel, Engineering
Systems Division, Massachusetts Institute of Technology 2
Motivation• The air transportation system is facing and will
continue
to face significant challenges in terms of meeting demand for
mobility
• Current multi-agency effort to establish a roadmap for the
“Next Generation of Air Transportation System”
• Navigation in current system under most conditions requires
use of fixed-location of current infrastructure to facilitate
mobility
• Future (evolved) architecture of the system require
understanding of the structure of the current system
• Lack of integrated quantitative analysis of structure of the
current system
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© 2005 Philippe A. Bonnefoy, Roland E. Weibel, Engineering
Systems Division, Massachusetts Institute of Technology 3
Objective of the project• Better understand the architecture of
the current system
through network analyzes• Understand
– the network characteristics of individual system layers–
Influence of constraints, desired properties (i.e. safety,
capacity,
etc.) in explanation of network characteristics– comparison of
network characteristics across different layers,
through coupling of infrastructure or comparison of different
network characteristics across layers
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© 2005 Philippe A. Bonnefoy, Roland E. Weibel, Engineering
Systems Division, Massachusetts Institute of Technology 4
Overview of the System
Infrastructure layer
Operator layer
Transport layer
Mobility layer
System layer
Ground
Airspace
Demand layer
National Airspace System(airports layout and airspace
structure)
Crews & Pilots
Aircraft routes
Movements of People and goods
Layer attributes
Population, income,location of businesses
SUPP
LY
Scheduled
On-Demand
DEM
AND
Data sources
FAA Form 5010 airportdatabase, airway
ETMS, OAG
DB1B database
ArcGIS, Census
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© 2005 Philippe A. Bonnefoy, Roland E. Weibel, Engineering
Systems Division, Massachusetts Institute of Technology 5
Infrastructure Layer Analysis
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© 2005 Philippe A. Bonnefoy, Roland E. Weibel, Engineering
Systems Division, Massachusetts Institute of Technology 6
Navigation Infrastructure Analysis
• Nodes: FAA-Defined Navigational Aids of Different Types– VORs,
Reporting Points, etc
• Links: Air Routes Between Nodes– Victor (low alt) & Jet
Routes (high alt)
• Network Metrics– Clustering Coefficient (Watts method) – Proxy
for robustness of
network– Correlation Coefficient
• Architecture Analyses– Shortest-Path Navigational vs. Direct
Distance between
Airports– Nodal Betweenness/Centrality
Nodes & Link Highlighted
Image removed for copyright reasons.Chart of jet routes.
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© 2005 Philippe A. Bonnefoy, Roland E. Weibel, Engineering
Systems Division, Massachusetts Institute of Technology 7
Degree Sequence
0
500
1000
1500
2000
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15Degree
Freq
uenc
y
Other PointsVOR/VORTAC
020406080
100120
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15Degree
Freq
uenc
y
Victor Airways-All Points (left)-VOR/VORTAC (below)
0100200300400500600
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15Degree
Freq
uenc
y
Other PointsVOR/VORTAC
05
101520253035
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15Degree
Freq
uenc
y
Jet Routes-All Points (left), VOR/VORTAC (right)
NavAid Network n m C (Watts) r0.1928 -0.0166
-0.07280.2761Jet Routes 1787 4444Victor Airways 2669 7635
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© 2005 Philippe A. Bonnefoy, Roland E. Weibel, Engineering
Systems Division, Massachusetts Institute of Technology 8
Navigation Architecture Analysis
• End Nodes: Navaids corresponding to published airports
• Geodesic (shortest path by navigational distance) computed
between top 1,000 airport pairs– Airports ranked based on 2004 FAA
traffic data– A-Star search algorithm implemented to find shortest
distance along
network
• Results – Dynamics Along Network– Navigational Distance
Compared to Shortest Path Distance by
Airport Ranking – Maximum “direct-to” efficiency– Betweenness
centrality to be calculated for navigation nodes as
measure of their utilization• Number of shortest-paths through
nodes as a proportion to total
shortest paths
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© 2005 Philippe A. Bonnefoy, Roland E. Weibel, Engineering
Systems Division, Massachusetts Institute of Technology 9
Navigation Distance Results
6.0%
6.5%
7.0%
7.5%
8.0%
8.5%
9.0%
0 200 400 600 800 1000 1200
Number of Airport Pairs
% D
ista
nce
Red
uctio
n
∑ ∑>
=airports airportsn
i
n
ij,jijdd
)
dd̂1%reduction −=
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© 2005 Philippe A. Bonnefoy, Roland E. Weibel, Engineering
Systems Division, Massachusetts Institute of Technology 10
Transport Layer Analysis
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© 2005 Philippe A. Bonnefoy, Roland E. Weibel, Engineering
Systems Division, Massachusetts Institute of Technology 11
0.001
0.01
0.1
1
1 10 100 1000 10000
Degree
Cum
ulat
ive
Prob
abili
ty p
(>k)
Wide/Narrow Body &Regional Jets
WB/NB/RJ + with primary &secondary airportsaggregated
Preliminary Analysis of the Wide-Body/Narrow Body &Regional
Jet Flight Network
Degree Distribution
Regional JetsRegional Jets
Wide Body JetsWide Body Jets Narrow Body JetsNarrow Body
Jets
(Images removed forcopyright reasons.)
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© 2005 Philippe A. Bonnefoy, Roland E. Weibel, Engineering
Systems Division, Massachusetts Institute of Technology 12
Analysis of the Wide-Body/Narrow Body & Regional Jet Route
Network
y = 1.85x-0.49
0.01
0.1
1
10
1 10 100 1000 10000
Degree
Cum
ulat
ive
Prob
abili
ty p
(>k)
WB/NB/RJ + w ith primary &secondary airports
aggregatedBeyond Pow er Law
Pow er (WB/NB/RJ + w ith primary &secondary airports
aggregated)
Coefficient of the degree distribution power law function: γ =
1.49
Hypotheses for the exponential cut-off:- Nodal capacity
constraints- Connectivity limitations between core and secondary
airports- Spatial constraints
Degree Distribution Analysis
Network Characteristics
Network n m Density Clustering coeff. rCentrality
vs.connectivity
-0.3913/20
most central also part of the top 20 most
connected
0.64Scheduled
transportation network
249 3389 0.052
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© 2005 Philippe A. Bonnefoy, Roland E. Weibel, Engineering
Systems Division, Massachusetts Institute of Technology 13
Preliminary Analysis of the Light Jet Route Network
Light JetsLight Jets
0.0001
0.001
0.01
0.1
1
1 10 100 1000 10000
Degree
Cum
ulat
ive
Freq
uenc
y (n
(>k)
)
Degree Distribution
Image removed for copyright reasons.
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© 2005 Philippe A. Bonnefoy, Roland E. Weibel, Engineering
Systems Division, Massachusetts Institute of Technology 14
Analysis of the Light Jet Route Network
Degree distribution identified as resulting from sub-linear
preferential attachment.
Degree Distribution Analysis
Network Characteristics
Network n m Density Clustering coefficient r
0.12 0.0045Light Jet Network(Unscheduled)
900 5384 0.005
0.0001
0.001
0.01
0.1
1
1 10 100 1000 10000
Degree
Cum
ulat
ive
Freq
uenc
y (n
(>k)
)
Power law network degree signature
Light Jet Network ⎥⎦
⎤⎢⎣
⎡⎟⎟⎠
⎞⎜⎜⎝
⎛−−
−=−−
−
γµ
γγγ
12exp.
11kkank
with: γ = 0.57µ = 0.16a = 0.13
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© 2005 Philippe A. Bonnefoy, Roland E. Weibel, Engineering
Systems Division, Massachusetts Institute of Technology 15
0
10
20
30
40
50
60
70
80
90
0 200 400 600 800 1000 1200 1400
Scheduled Traffic WB/NB/RJ(weighted degree)
Uns
cehd
uled
Tra
ffic
LJ(w
eigh
ted
degr
ee)
Interactions between Transport Layers
TEB
ATL
SEA
ORD
CMH
CLT
DFW
Scheduled
On-Demand
Transport layer
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© 2005 Philippe A. Bonnefoy, Roland E. Weibel, Engineering
Systems Division, Massachusetts Institute of Technology 16
Demand Layer Analysis
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© 2005 Philippe A. Bonnefoy, Roland E. Weibel, Engineering
Systems Division, Massachusetts Institute of Technology 17
Analysis of the Demand Layer
0.00001
0.0001
0.001
0.01
0.1
10.0 0.1 1.0 10.0
Size of population basin (b) [in millions]
Cum
ulat
ive
Den
sity
Fun
ctio
n p(
>b)
• Single Layer Analysis
Population/Airport Gravity Model
based on 66,000 Census Track data
• Non scale free nature of distribution of population around
airports
⎭⎬⎫
⎩⎨⎧ === ∑
∈jctjictiCct
cti ddctCtspbi
,, min..
Notations:
Pct: population of census track ct
bi: size of population basin around airport i
ct: census track
di,j: Euclidean distance
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© 2005 Philippe A. Bonnefoy, Roland E. Weibel, Engineering
Systems Division, Massachusetts Institute of Technology 18
Questions & Comments
Thank you
Air Transportation System Architecture AnalysisProject Phase
IIAdvanced System ArchitectureSpring 2006MotivationObjective of the
projectOverview of the SystemInfrastructure Layer
AnalysisNavigation Infrastructure AnalysisDegree SequenceNavigation
Architecture AnalysisNavigation Distance ResultsTransport Layer
AnalysisPreliminary Analysis of the Wide-Body/Narrow Body
&Regional Jet Flight NetworkAnalysis of the Wide-Body/Narrow
Body & Regional Jet Route NetworkPreliminary Analysis of the
Light Jet Route NetworkAnalysis of the Light Jet Route
NetworkInteractions between Transport LayersDemand Layer
AnalysisAnalysis of the Demand LayerQuestions & Comments