Route Planning in Transportation Networks

We survey recent advances in algorithms for route planning in transportation networks. For road networks, we show that one can compute driving directions in milliseconds or less even at continental scale. A variety of techniques provide different trade-offs between preprocessing effort, space requirements, and query time. Some algorithms can answer queries in a fraction of a microsecond, while others can deal efficiently with real-time traffic. Journey planning on public transportation systems, although conceptually similar, is a significantly harder problem due to its inherent time-dependent and multicriteria nature. Although exact algorithms are fast enough for interactive queries on metropolitan transit systems, dealing with continent-sized instances requires simplifications or heavy preprocessing. The multimodal route planning problem, which seeks journeys combining schedule-based transportation (buses, trains) with unrestricted modes (walking, driving), is even harder, relying on approximate solutions even for metropolitan inputs.Comment: This is an updated version of the technical report MSR-TR-2014-4, previously published by Microsoft Research. This work was mostly done while the authors Daniel Delling, Andrew Goldberg, and Renato F. Werneck were at Microsoft Research Silicon Valle

A précis of philosophy of computing and information technology

The authors recently finished a comprehensive chapter on “Philosophy of Computing and Information Technology” for the forthcoming (fall 2009) Philosophy of Technology and Engineering Sciences (Ed.: A. Meijers), Volume IX in the Elsevier series Handbook of the Philosophy of Science (Eds.: D. Gabbay, P. Thagard and J. Woods). The purpose of the chapter is to review and discuss the main developments, concepts, topics, and contributors in the intersection between philosophy and computing, as well as provide some suggestions on how to structure the many subcategories within what is loosely referred to as philosophy of computing. In this short synopsis, we will give an outline of the kinds of issues raised in this chapter