On-line single-server dial-a-ride problems

Online multi-server dial-a-ride problems

In an online dial-a-ride problem, a crew of servers has to process transportation requests as they arrive in real time. Possible objective functions include minimizing the makespan and minimizing the sum of completion times. We give competitive algorithms and negative results for several online dial-a-ride problems with multiple servers. Surprisingly, in some cases the competitive ratio is dram...

Online Dial-a-Ride Problems: Minimizing the Completion Time

Euler is Standing in Line Dial - a - Ride Problems with FIFO - Precedence - Constraints

In this paper we study algorithms for “Dial-a-Ride” transportation problems. In the basic version of the problem we are given transportation jobs between the vertices of a graph and the goal is to find a shortest transportation that serves all the jobs. This problem is known to be NP-hard even on trees. We consider the extension when precedence relations between the jobs with the same source ar...

Computer-Aided Complexity Classification of Dial-a-Ride Problems

Cap Gemini Ernst & Young, P.O. Box 2575, 3500 GN Utrecht, The Netherlands CWI, P.O. Box 94079, 1090 GB Amsterdam, The Netherlands Mathematical Institute, Academy of Sciences of the Czech Republic, Žitná 25, CZ-11567 Praha 1, Czech Republic Department of Mathematics and Computer Science, Technische Universiteit Eindhoven, P.O. Box 513, 5600 MB Eindhoven, The Netherlands Department of Mathematics...

Efficient feasibility testing for dial-a-ride problems

Dial-a-Ride systems involve dispatching a vehicle to satisfy demands from a set of customers who call a vehicle operating agency requesting that an item be picked up from a specific location and delivered to a specific destination. Dial-a-ride problems differ from other routing and scheduling problems in that they typically involve service related constraints. It is common to have maximum wait ...