1. The Flight Network

2. What is a network and why should I care?
Networks key elements
A network is comprised of two key elements. One being a point also referred to as an vertex. The other being a line also referred to as an edge.
Example of a network
A few examples of networks would be online gaming, for example when you are playing an online game you are connected to the server which is connected to other players playing as well.
Why should I care?
Networks are all around us and understanding how these networks work and their weak points and strengths will help to solve problems among the networks. We can also learn from the weakness of other networks to develop our own superior networks in the future.

3. Air Traffic Characterized as a network
Each airport can be thought of as a node.
Each flight can be thought of as an edge.
Function of flights are to transport people in the quickest way available.
Airplanes are packets being transferred by nodes through lines.
Packets ship from node to node until intended destination is reached

4. Air Traffic Characterized as a network
Multigraph in Airline Traffic control shows all the connections between two airports.
The Air Traffic Network provides a safe sky between nodes and avoids incidents between flights.

5. Importance of Air Traffic Networks
There are approximately 87,000 flights per day in the U.S and an average of 102,465 per day in the entire world.
At any given time there is 8,000-10,000 flights in the air.
The study of air traffic networks allows for such complex networks to run seamlessly.
Prevention of infectious diseases

6. Dirk Brockmann discovery and modeling of global mobility network
WheresGeorge.com is an online bill tracking system that provided data for the groundbreaking research
Mathematically analyzed the human mobility network from a few to a few thousand miles.
Led to discovery of scaling laws which is key for modeling pandemic disease forecast

7. Structure of the Flight Network
The structure of the network affects how efficient flights are between airports (nodes), and availability of flights throughout the world.
Makes all the flight undirected, where paths are allowed to go either way along any edge, so flight can arrive in less time.
Trees would be more specified for undirected network, since it would be no closed loops in airplanes direction.

8. Mathematical Models and Methods used with transportation systems
A method developed by Jin Qin and Yuxin He can show how a network will be affected based off of: the amount of traffic, route choices by users, demand and a networks structure.
The input can be changed to determine an efficiency.
nA is the number of elements, xa is the flow of a link, ta is the travel cost, this analysis runs from point a to A, EQH is the efficiency of the network.

9. Typical Research Questions
The flight network has endless possibilities which also means there is always room for improvement.
How should we choose the route a plane flies?
Is the shortest route to fly always the fastest?
- Due to a variety of conditions this is not always the case
How can air traffic slowdowns and bottlenecks be avoided?
What happens when a vertex or edge fails?
Where can new flights be added?
How can we catch, stop or contain disease outbreak using this network?

10. Transportation Network Studies

11. Atlanta Airport 11 hour shutdown
Atlanta Airport shut down and over 1,500 flights were grounded due to a power outage. The airport acts as a Vertex in which multiple edges (planes) connect to. With this vertex no longer connected to the network 1500 different edges were severed and essentially useless until the vertex was restored. This is a good example of how a network can be damaged from a single vertex issue. Although NASA has a developed programs to help combat some of these issues, most notably their software labeled FACET.

12. NASA and Air Traffic Networks
FACET
Facet is short for Future Air Traffic Management Concepts Evaluation Tool, was developed to show Air Traffic and simulate changes in Air Traffic. These simulations can include, but are not limited to: change in weather conditions, flight additions or subtractions and more.
Benefits to using FACET
Using FACET allows NASA to help better regulate air traffic and prevent incidents. The use of this system can also help improve efficiency of flights and save the airline companies money which translates to savings for the consumers.

13. FACET-WEATHER

14. FACET-GLOBAL

15. How FACET helps research the network
The lead developer Dr. Kapil Sheth was quoted saying: “We’ve used this capability to study the impact of global aviation emissions on the environment”.
The studies can not only help Airlines with efficiency and safety but also help NASA analyse global emissions due to airlines.
The next generation of this software will be used in the cockpit to track weather patterns and dangers more easily and allow flight paths to change if needed in an emergency
The next generation of FACET will also allow airlines to better track arrival times based off a variety of unforeseen conditions.

17. Works Cited
“Research on Complex Systems.” The Scaling Laws of Human Travel - Research on Complex Systems, ESAM, Northwestern University, rocs.northwestern.edu/projects/scaling_laws.html.
“Where's George?” Wikipedia, Wikimedia Foundation, 24 Jan. 2018, en.wikipedia.org/wiki/Where%27s_George%3F.
He, Yuxin, et al. “Comparative Analysis of Quantitative Efficiency Evaluation Methods for Transportation Networks.” PLOS ONE, Public Library of Science, journals.plos.org/plosone/article?id= %2Fjournal.pone
Gipson, Lillian. “NASA Air Traffic Management Research Tool Shows New Colors.” NASA, NASA, 7 Sept. 2017,