Method and system for rescheduling passengers
A method of generating solutions for rescheduling objects such as passengers and cargo. The objects are grouped into subproblems according to segments. Initial solutions are generated without varying the origin and destination for any of the objects. Upon creating the initial solutions, objects that are unsuitably rescheduled are grouped together and rescheduled without constraint to reduce the scope of the original rescheduling problem. The reduced problem is then reevaluated for further improvement.
1 . A method for generating a solution to a problem having objects scheduled originally in itineraries, each original itinerary having at least an origin and a destination, the method comprising the steps of:
receiving a disruption specification based upon an event, the disruption specification including data identifying the objects to be rescheduled;
receiving a request for rescheduling of the objects from a user;
grouping the objects to be rescheduled into subproblems, wherein each subproblem is defined by each object therein having the same original origin and destination;
applying a first algorithm to each subproblem without allowing varying the origin and destination of the objects in the subproblem for simplification and, in turn, quickly reaching initial solutions;
identifying a subclass of objects that are unsuitably rescheduled in the initial solutions; and
applying a second algorithm for rescheduling the subclass that allows varying the original itinerary to generate rescheduling solutions for the subclass.
2 . A method as recited in claim 1 , further comprising the step of applying a third algorithm to an IP problem based upon all of the objects.
3 . A method as recited in claim 2 , wherein the third algorithm is an IP algorithm with a branch and bound technique.
4 . A method as recited in claim 2 , further comprising the steps of excluding the subclass of objects from the objects that need to be rescheduled in the disruption specification and applying a fourth algorithm to the remaining objects in the reduced disruption specification to determine rescheduling solutions for the remaining objects.
5 . A method according to claim 4 , wherein the first and fourth algorithms are transportation simplex algorithms.
6 . A method as recited in claim 1 , wherein the subclass of objects to be rerouted are identified based upon a suitably of rescheduling criteria.
7 . A method as recited in claim 6 , wherein identifying the subclass includes determining a cost for each rescheduled object and comparing the cost to a threshold.
8 . A method as recited in claim 1 , wherein the objects are passengers traveling one or more legs between the origin and the destination.
9 . A method as recited in claim 1 , wherein the rescheduling solutions include upgrading, downgrading, delaying, and offloading the objects.
10 . A method according to claim 1 , wherein the second algorithm is selected from the group consisting of the Dijkstra algorithm and a K-shortest path algorithm.
11 . A method for generating solutions to problems having objects scheduled in itineraries, the method comprising the steps of:
receiving a disruption specification based upon an event, the disruption specification including data identifying at least one object to be rerouted;
applying a shortest path algorithm to generate a plurality of possible solutions for rerouting the at least one object;
forming an IP problem based upon the plurality of possible solutions; and
applying an IP algorithm to the IP problem for generating a practical solution for rerouting the at least one object.
12 . A method as recited in claim 11 , wherein the event is selected from the group consisting of an airplane breakdown, a hub closing, flight cancellation and a weather storm.
13 . A method as recited in claim 11 , wherein the IP algorithm utilizes a branch and bound technique.
14 . A method for generating solutions to problems having objects scheduled in itineraries, the method comprising the steps of:
receiving a disruption specification based upon an event, the disruption specification including data identifying objects to be rerouted;
grouping the objects to be rescheduled into subproblems, wherein each subproblem is defined by each object therein having the same original origin and destination; and
applying an algorithm for generating solutions to each subproblem.
15 . A method as recited in claim 14 , wherein the algorithm is a transportation algorithm.
16 . A method as recited in claim 14 , further comprising the steps of:
identifying a subclass of objects that are unsuitably rescheduled in the initial solutions;
applying a shortest path algorithm for rescheduling the subclass to generate additional possible rescheduling solutions for the each object in the subclass.
17 . A method as recited in claim 16 , further comprising the steps of:
applying an IP algorithm based upon the additional possible rescheduling solutions to generate a practical solution for rerouting the objects.
18 . A method as recited in claim 17 , further comprising the steps of:
excluding the identified subclass to reduce the disruption specification; and
solving the reduced specification by applying a transportation algorithm.
19 . A method as recited in claim 18 , further comprising the step of varying the origin and destination of the objects only at the step of solving the reduced specification.
20 . A method as recited in claim 18 , further comprising the step of grouping the objects by segment prior to solving the reduced disruption specification
21 . A method for generating solutions to problems having objects scheduled in itineraries, the method comprising the steps of:
receiving a disruption specification based upon an event, the disruption specification including data identifying objects to be rerouted;
grouping the objects to be rescheduled into subproblems, wherein each subproblem is defined by each object therein having the same original origin and destination;
applying a transportation algorithm for generating solutions to each subproblem;
identifying a subclass of objects that are unsuitably rescheduled in the initial solutions; and
applying a shortest path algorithm for rescheduling the subclass to generate multiple possible rescheduling solutions for the each object in the subclass; and
applying an IP algorithm based upon the transportation algorithm and shortest path algorithm solutions to generate a practical solution for rerouting the objects.
excluding the subclass of objects from the objects that need to be rescheduled in the disruption specification; and
applying a fourth algorithm to the remaining objects in the reduced disruption specification to determine rescheduling solutions for the remaining objects.
22 . A method according to claim 21 , wherein during applying the shortest path algorithm, a temporal limitation of arrival time is included in the disruption specification.
23 . A method according to claim 21 , wherein the forth algorithm is the same as the transportation algorithm.
24 . A method as recited in claim 21 , wherein the objects are passengers traveling on one of a group consisting of an airplane, a train and a bus.
25 . A method as recited in claim 21 , wherein the IP algorithm uses a branch and bound technique with a cost function.
26 . A method as recited in claim 21 , wherein the cost function is
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wherein: an itinerary class (hereinafter “IC”) is an itinerary consisting of a sequence of cabin classes on specific flights; a PaxGroup (hereinafter “PG”) is a group of passengers that have booked the same itinerary and are booked in the same cabin class on each of the flights in the itinerary; x ij is the number of passengers from PG i, who are assigned to ICj; c ij is the cost of assigning one passenger from PG i to IC j ; u i is the cost of leaving one passenger from PG i unhandled; and N i is the number of passengers in PG i .
27 . An engine for generating solutions to a rescheduling disruption of objects comprising:
applying a first process for large problems; and
applying a second process for small problems, wherein the small and large problems are defined by a user.
28 . A method according to claim 27 , wherein the first process includes the steps of:
receiving a disruption specification based upon an event, the disruption specification including data identifying objects to be rerouted;
grouping the objects to be rescheduled into subproblems, wherein each subproblem is defined by each object therein having the same original origin and destination;
applying a transportation algorithm for generating solutions to each subproblem;
identifying a subclass of objects that are unsuitably rescheduled in the initial solutions; and
applying a shortest path algorithm for rescheduling the subclass to generate additional possible rescheduling solutions for the each object in the subclass.
29 . A method according to claim 27 , wherein the first process further includes the step of solving an IP problem for all passengers.
30 . A method according to claim 27 , wherein the second process includes the steps of:
receiving a disruption specification based upon an event, the disruption specification including data identifying at least one object to be rerouted;
applying a shortest path algorithm to generate a plurality of LP solutions for rerouting the at least one object; and
applying an IP algorithm based upon the plurality of LP solutions to generate a practical solution for rerouting the at least one object.
31 . A method according to claim 27 , wherein the second process includes the steps of:
receiving a disruption specification based upon an event, the disruption specification including data identifying objects to be rerouted;
grouping the objects to be rescheduled into subproblems, wherein each subproblem is defined by each object therein having the same original origin and destination; and
applying a transportation algorithm for generating solutions to each subproblem.