Intelligent rail-air travel planner

Describes a model of expert human reasoning which reaches the same conclusions that the human expert would reach for any given origin/destination combination from a train/airline schedule on a rail-air network. The route suggested by the model can be optimized on journey time, distance/fare, or number of changeover stations. This necessitates representation of imprecise and noncategorical knowledge in a computational framework so that it can be exploited by the model. This model was designed to minimize interaction with passengers by given prompt, precise, and complete information. The authors decided to use the A* algorithm-probably the best known heuristic search technique. However, for the network size under consideration and the number of parameters/constraints involved, the time taken to find an optimal path was large. To overcome this problem, the concept of a virtual network consisting of multiple fully-connected context-sensitive virtual layers is introduced. The modified A* algorithm is referred to as A* virtual or A*V. Output is presented in the form of an itinerary or list of all trains/flights between each leg of a journey