5,978 research outputs found
A Fast and Tight Heuristic for A* in Road Networks
No full textWe study exact, efficient and practical algorithms for route planning in large road networks. Routing applications often require integrating the current traffic situation, planning ahead with traffic predictions for the future, respecting forbidden turns, and many other features depending on the exact application. While Dijkstra’s algorithm can be used to solve these problems, it is too slow for many applications. A* is a classical approach to accelerate Dijkstra’s algorithm. A* can support many extended scenarios without much additional implementation complexity. However, A*’s performance depends on the availability of a good heuristic that estimates distances. Computing tight distance estimates is a challenge on its own. On road networks, shortest paths can also be quickly computed using hierarchical speedup techniques. They achieve speed and exactness but sacrifice A*’s flexibility. Extending them to certain practical applications can be hard. In this paper, we present an algorithm to efficiently extract distance estimates for A* from Contraction Hierarchies (CH), a hierarchical technique. We call our heuristic CH-Potentials. Our approach allows decoupling the supported extensions from the hierarchical speed-up technique. Additionally, we describe A* optimizations to accelerate the processing of low degree nodes, which often occur in road networks
sj-docx-1-evi-10.1177_13563890231204664 – Supplemental material for Applying SCALE 3D for evaluating transformative social innovation
No full textSupplemental material, sj-docx-1-evi-10.1177_13563890231204664 for Applying SCALE 3D for evaluating transformative social innovation by Tim Strasser and Joop de Kraker in Evaluation</p
Space-Efficient, Fast and Exact Routing in Time-Dependent Road Networks
No full textWe study the problem of computing shortest paths in massive road networks with traffic predictions. Incorporating traffic predictions into routing allows, for example, to avoid commuter traffic congestions. Existing techniques follow a two-phase approach: In a preprocessing step, an index is built. The index depends on the road network and the traffic patterns but not on the path start and end. The latter are the input of the query phase, in which shortest paths are computed. All existing techniques have either large index size, slow query running times, or may compute suboptimal paths. In this work, we introduce CATCHUp (Customizable Approximated Time-dependent Contraction Hierarchies through Unpacking), the first algorithm that simultaneously achieves all three objectives. The core idea of CATCHUp is to store paths instead of travel times at shortcuts. Shortcut travel times are derived lazily from the stored paths. We perform an experimental study on a set of real world instances and compare our approach with state-of-the-art techniques. Our approach achieves the fastest preprocessing, competitive query running times and up to 30 times smaller indexes than competing approaches
Do dolphins benefit from nonlinear mathematics when processing their sonar returns?
No full textAn interview with author Tim Leighton about the paper
Opportunities for linking young surveyors across professional surveying member organisations and FIG
No full textTim Di Muzio on 'Sabotage'
No full textIn a series of essays published in 2013 and 2014 on capitaspower.com, political economist Tim Di Muzio explored the concept of ‘sabotage’ as it applies to capitalist power. I recently rediscovered these essays and was so impressed by them that I have reposted them here as a single piece.
About the author: Tim Di Muzio is a researcher at the University of Wollongong. He is the author of numerous books, including Debt as power, Carbon capitalism, and The 1% and the Rest of us
1996-1997 Tim Gautreaux
No full textTim Gautreaux is the author of three novels and two earlier short story collections. His work has appeared in The New Yorker, The Best American Short Stories, The Atlantic, Harper’s, and GQ. After teaching for thirty years at Southeastern Louisiana University, he now lives, with his wife, in Chattanooga, Tennessee. (Photo credit: Randy Bergeron)https://egrove.olemiss.edu/grisham_res/1023/thumbnail.jp
First person - Tim Petzold
No full textFirst Person is a series of interviews with the first authors of a selection of papers published in Biology Open, helping researchers promote themselves alongside their papers. Tim Petzold is first author on ‘ Connexin 41.8 governs timely haematopoietic stem and progenitor cell specification’, published in BiO. Tim conducted the research described in this article while a PhD student in Julien Bertrand's lab at the Department of Pathology and Immunology, Faculty of Medicine, University of Geneva, Switzerland. He is now a postdoc in the lab of Holger Gerhardt at the Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany, investigating developmental biology – previously his focus was on how blood stem cells develop and now it has shifted to how the vascular system develops
Tim Seibles, 40th Annual ODU Literary Festival
No full textTim Seibles is the author of several poetry collections including Hurdy-Gurdy, Hammerlock, Buffalo Head Solos, and Fast Animal, which was a finalist for the 2012 National Book Award. In 2013 he received both the Pen Oakland Josephine Miles Award for poetry and an honorary Doctorate of Humane Letters from Misericordia University for his literary accomplishments. His latest collection, One Turn Around the Sun, has just been released. Tim is the current Poet Laureate of Virginia and is a Professor of English at Old Dominion University where he teaches literature as well as classes in the MFA in writing program
Tim Seibles, 39th Annual ODU Literary Festival
No full textTim Seibles is the author of several poetry collections including Hurdy-Gurdy, Hammerlock, Buffalo Head Solos, and Fast Animal, which was a finalist for the 2012 National Book Award. In 2013 he received both the Pen Oakland Josephine Miles Award for poetry and an honorary Doctorate of Humane Letters from Misericordia University for his literary accomplishments. His latest collection, One Turn Around the Sun, has just been released. Tim is the current Poet Laureate of Virginia and is a Professor of English at Old Dominion University where he teaches literature as well as classes in the MFA in writing program
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