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Operations Research in Air Transportation. Air Transportation System. Infrastructure Airports ATM (Air Traffic Management) ATFM (AT Flow Management) ATC (AT Control) Superstructure Commercial Flights Private Flights Military Flights.
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Air Transportation System • Infrastructure • Airports • ATM (Air Traffic Management) • ATFM (AT Flow Management) • ATC (AT Control) • Superstructure • Commercial Flights • Private Flights • Military Flights
ATM (AT Management) Motivation for improvement • New technologies • CNS (Communications Navigation Surveillance) • Datalink • Better weather forecasting • New economic framework • Deregulation • Liberalization • Competition
Aviation Authorities (ICAO, FAA, Eurocontrol, National Aviation Authorities) are adopting new ATM concepts: • FANS (Future Air Navigation System) • Free Flight • CDM (Collaborative Decision Making) and tools, for example: • COMPAS • MAESTRO • CTAS
SAFETY • Primary objective of ATM system • Same separation rules in the last 15 years (except for vertical separation …) • Lack of quantitative models • Need for a greater flexibility • Implementation of new concepts requires careful examination (example: implications of Free Flight)
ATFM (AT Flow Management) • Providers • FAA • Eurocontrol CFMU (Central Flow Management Unit) • ATM is continuously evolving • Excellent information, elaboration and visualization capabilities • Lack of satisfactory decision support systems • Need for real time tools able to handle uncertainties (e.g., weather) and dynamically changing reality.
Over 95% of the total EUROCONTROL Route charges revenues
Demand Scheduled flights Charter flights General Aviation Military flights State flights … System Capacity Airports (number of take-off/landings) Airways Sectors (no. of flights entering the sector or no. of flights in the sector) ATFM
First solution: Ground Holding • Ground holding safer than airborne holding • Ground holding cheaper than airborne holding N.B.: Flight shift in time
Second solution: Rerouting • It is sometimes directly imposed by the Aviation Authority (CFMU) • Could be in-directly imposed: air traffic demand management N.B.: flight shift in space
Ground Holding • Ground holding better than airborne delay • History: 1981 USA AT controllers strike • Dimensions (No. of daily flights): • 60,000 domestic flights in USA • 30,000 flights in Eurocontrol zone
Ground Holding Problem MIT Padova University
GH model(meaning) MIN Total Cost of (ground + airborne delays) subject to: • Capacity constraints • Assignment constraints • Coupling constraints • Integrality constraints
GH model(type and dimensions) • The resulting model is a MIP (Mixed Integer Programming) problem with a few hundred thousands boolean variables and constraints • The problem is NP-hard (i.e., difficult) • Yet, the instances using real data were easy to solve
Rerouting A rerouting is sometimes imposed by CFMU. Rerouting implies different route charges! € € € € € € €
EUROCONTROLroute charge formula Totalcost: where for each State i the charge is given by: Distance traveled in State i Unit rate in State i
Critics to EUROCONTROL formula: Should better reflect actual ATC costs: • Use time rather than distance? • Question the importance of weight (augment the exponent from 0.5 to 0.87 ?) • Efficiency in providing ATC services should be taken into account • …
Air Navigation and Airport User Charges • Great interest internationally • Background of rising infrastructure costs and security costs at a time of global industry crisis • Multiple objectives for charging systems: • Cover costs of service providers • Cost-related charging formulae • Provide incentives to improve efficiency/performance of service providers • Inform prioritization of investments • Promote operational efficiency (e.g., reduce congestion) • Transparency and user participation • etc.
IRCSproject(Trieste + Padova) Innovative Route Charging Schemes For more information see: www.eurocontrol.int/care/innovative/projects2002/ircs/
IRCS Specific Issues (partial list) • Alternative charging formulae • Common unit rate • Two-part charge, etc. • Impacts of alternative charging systems • Charge according to flight plan • Tax on tickets • Containment of service provider costs • Other?
General aim of IRCS project the final purpose of the Innovative Route Charging Schemes project is: • to study the impact of changes in en-route charges • with respect to the demand and supply sides of ATM • in a view to improve the overall efficiency of the system
Market based Flow Demand Management and Rerouting Odoni, Fan, … (MIT) Andreatta, Lulli (Padova)
Optimal congestion fee A congestion fee on a user is optimal when it is equal to the external costs that the user imposes on the other users. For a M/G/1 queue: Marginal Internal External cost cost cost + =
Idea under investigation • Without congestion fee, BIG aircraft are penalized • With “optimal” congestion fee, SMALL aircraft are penalized Why not consider different categories and compute the “external” cost imposed within each category?
Airport modeling • Landside (Passenger terminal) • Baggage handling • Apron stand allocation • Arrival aircraft sequencing
Airport landside modeling European sponsored projects: • IV UE framework program: “TAPE” • V UE framework program: “OPAL” • VI UE framework program: “SPADE” Padova University Rome “La Sapienza” University Athens AUEB Toulouse ONERA Delft University
Input file Output file Output file Output file run SLAM Implementation • Program: ANSI C, LEX and YACC • Graphic User Interface: JAVA • Run under UNIX and WINDOWS
Apron stand allocation Romanin-Jacur, Filippi
Arrival aircraft sequencing Bianco, Rinaldi, Dell’Olmo, Lulli, …
Airlines Deregulation and Liberalization drive a higher competition Need to reduce costs Need to enhance revenues
Airlines costs • The Passenger Mix Model • The Fleet Assignment Problem • The Crew Pairing Problem, the Aircraft Routing Problem, and the Integrated Crew Pairing-Aircraft Routing Problem • The Schedule Design Problem • Integrated Models
Airlines revenues • Revenue management • Seat pricing • Seat categorization • Integration
Optimization Methods • Integer Linear Programming • Greedy algorithms • Genetic algorithms • Tabu search • Bi-linear programming models
Where in the USA ? • NEXTOR • MIT • Virginia TECH • U. of Maryland • UC Berkeley • GMU • FAA
Where in Italy • Padova • Andreatta, Brunetta, Lulli, Romanin-Jacur, … • Rome • Dell’Olmo, Bianco, … • Trieste • Ukovich, Castelli, Pesenti, … • Siena • Marti
Thank You Padova References: www.dei.unipd.it/~brunetta/at_papers/