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Documents authored by Devanny, William E.


Document
Optimally Sorting Evolving Data

Authors: Juan Jose Besa, William E. Devanny, David Eppstein, Michael T. Goodrich, and Timothy Johnson

Published in: LIPIcs, Volume 107, 45th International Colloquium on Automata, Languages, and Programming (ICALP 2018)


Abstract
We give optimal sorting algorithms in the evolving data framework, where an algorithm's input data is changing while the algorithm is executing. In this framework, instead of producing a final output, an algorithm attempts to maintain an output close to the correct output for the current state of the data, repeatedly updating its best estimate of a correct output over time. We show that a simple repeated insertion-sort algorithm can maintain an O(n) Kendall tau distance, with high probability, between a maintained list and an underlying total order of n items in an evolving data model where each comparison is followed by a swap between a random consecutive pair of items in the underlying total order. This result is asymptotically optimal, since there is an Omega(n) lower bound for Kendall tau distance for this problem. Our result closes the gap between this lower bound and the previous best algorithm for this problem, which maintains a Kendall tau distance of O(n log log n) with high probability. It also confirms previous experimental results that suggested that insertion sort tends to perform better than quicksort in practice.

Cite as

Juan Jose Besa, William E. Devanny, David Eppstein, Michael T. Goodrich, and Timothy Johnson. Optimally Sorting Evolving Data. In 45th International Colloquium on Automata, Languages, and Programming (ICALP 2018). Leibniz International Proceedings in Informatics (LIPIcs), Volume 107, pp. 81:1-81:13, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2018)


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@InProceedings{besa_et_al:LIPIcs.ICALP.2018.81,
  author =	{Besa, Juan Jose and Devanny, William E. and Eppstein, David and Goodrich, Michael T. and Johnson, Timothy},
  title =	{{Optimally Sorting Evolving Data}},
  booktitle =	{45th International Colloquium on Automata, Languages, and Programming (ICALP 2018)},
  pages =	{81:1--81:13},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-076-7},
  ISSN =	{1868-8969},
  year =	{2018},
  volume =	{107},
  editor =	{Chatzigiannakis, Ioannis and Kaklamanis, Christos and Marx, D\'{a}niel and Sannella, Donald},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ICALP.2018.81},
  URN =		{urn:nbn:de:0030-drops-90858},
  doi =		{10.4230/LIPIcs.ICALP.2018.81},
  annote =	{Keywords: Sorting, Evolving data, Insertion sort}
}
Document
Square-Contact Representations of Partial 2-Trees and Triconnected Simply-Nested Graphs

Authors: Giordano Da Lozzo, William E. Devanny, David Eppstein, and Timothy Johnson

Published in: LIPIcs, Volume 92, 28th International Symposium on Algorithms and Computation (ISAAC 2017)


Abstract
A square-contact representation of a planar graph G = (V,E) maps vertices in V to interior-disjoint axis-aligned squares in the plane and edges in E to adjacencies between the sides of the corresponding squares. In this paper, we study proper square-contact representations of planar graphs, in which any two squares are either disjoint or share infinitely many points. We characterize the partial 2-trees and the triconnected cycle-trees allowing for such representations. For partial 2-trees our characterization uses a simple forbidden subgraph whose structure forces a separating triangle in any embedding. For the triconnected cycle-trees, a subclass of the triconnected simply-nested graphs, we use a new structural decomposition for the graphs in this family, which may be of independent interest. Finally, we study square-contact representations of general triconnected simply-nested graphs with respect to their outerplanarity index.

Cite as

Giordano Da Lozzo, William E. Devanny, David Eppstein, and Timothy Johnson. Square-Contact Representations of Partial 2-Trees and Triconnected Simply-Nested Graphs. In 28th International Symposium on Algorithms and Computation (ISAAC 2017). Leibniz International Proceedings in Informatics (LIPIcs), Volume 92, pp. 24:1-24:14, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2017)


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@InProceedings{dalozzo_et_al:LIPIcs.ISAAC.2017.24,
  author =	{Da Lozzo, Giordano and Devanny, William E. and Eppstein, David and Johnson, Timothy},
  title =	{{Square-Contact Representations of Partial 2-Trees and Triconnected Simply-Nested Graphs}},
  booktitle =	{28th International Symposium on Algorithms and Computation (ISAAC 2017)},
  pages =	{24:1--24:14},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-054-5},
  ISSN =	{1868-8969},
  year =	{2017},
  volume =	{92},
  editor =	{Okamoto, Yoshio and Tokuyama, Takeshi},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ISAAC.2017.24},
  URN =		{urn:nbn:de:0030-drops-82675},
  doi =		{10.4230/LIPIcs.ISAAC.2017.24},
  annote =	{Keywords: Square-Contact Representations, Partial 2-Trees, Simply-Nested Graphs}
}
Document
The Online House Numbering Problem: Min-Max Online List Labeling

Authors: William E. Devanny, Jeremy T. Fineman, Michael T. Goodrich, and Tsvi Kopelowitz

Published in: LIPIcs, Volume 87, 25th Annual European Symposium on Algorithms (ESA 2017)


Abstract
We introduce and study the online house numbering problem, where houses are added arbitrarily along a road and must be assigned labels to maintain their ordering along the road. The online house numbering problem is related to classic online list labeling problems, except that the optimization goal here is to minimize the maximum number of times that any house is relabeled. We provide several algorithms that achieve interesting tradeoffs between upper bounds on the number of maximum relabels per element and the number of bits used by labels.

Cite as

William E. Devanny, Jeremy T. Fineman, Michael T. Goodrich, and Tsvi Kopelowitz. The Online House Numbering Problem: Min-Max Online List Labeling. In 25th Annual European Symposium on Algorithms (ESA 2017). Leibniz International Proceedings in Informatics (LIPIcs), Volume 87, pp. 33:1-33:15, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2017)


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@InProceedings{devanny_et_al:LIPIcs.ESA.2017.33,
  author =	{Devanny, William E. and Fineman, Jeremy T. and Goodrich, Michael T. and Kopelowitz, Tsvi},
  title =	{{The Online House Numbering Problem: Min-Max Online List Labeling}},
  booktitle =	{25th Annual European Symposium on Algorithms (ESA 2017)},
  pages =	{33:1--33:15},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-049-1},
  ISSN =	{1868-8969},
  year =	{2017},
  volume =	{87},
  editor =	{Pruhs, Kirk and Sohler, Christian},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ESA.2017.33},
  URN =		{urn:nbn:de:0030-drops-78831},
  doi =		{10.4230/LIPIcs.ESA.2017.33},
  annote =	{Keywords: house numbering, list labeling, file maintenance}
}
Document
Scheduling Autonomous Vehicle Platoons Through an Unregulated Intersection

Authors: Juan José Besa Vial, William E. Devanny, David Eppstein, and Michael T. Goodrich

Published in: OASIcs, Volume 54, 16th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2016)


Abstract
We study various versions of the problem of scheduling platoons of autonomous vehicles through an unregulated intersection, where an algorithm must schedule which platoons should wait so that others can go through, so as to minimize the maximum delay for any vehicle. We provide polynomial-time algorithms for constructing such schedules for a k-way merge intersection, for constant k, and for a crossing intersection involving two-way traffic. We also show that the more general problem of scheduling autonomous platoons through an intersection that includes both a k-way merge, for non-constant k, and a crossing of two-way traffic is NP-complete.

Cite as

Juan José Besa Vial, William E. Devanny, David Eppstein, and Michael T. Goodrich. Scheduling Autonomous Vehicle Platoons Through an Unregulated Intersection. In 16th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2016). Open Access Series in Informatics (OASIcs), Volume 54, pp. 5:1-5:14, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2016)


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@InProceedings{besavial_et_al:OASIcs.ATMOS.2016.5,
  author =	{Besa Vial, Juan Jos\'{e} and Devanny, William E. and Eppstein, David and Goodrich, Michael T.},
  title =	{{Scheduling Autonomous Vehicle Platoons Through an Unregulated Intersection}},
  booktitle =	{16th Workshop on Algorithmic Approaches for Transportation Modelling, Optimization, and Systems (ATMOS 2016)},
  pages =	{5:1--5:14},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-021-7},
  ISSN =	{2190-6807},
  year =	{2016},
  volume =	{54},
  editor =	{Goerigk, Marc and Werneck, Renato F.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.ATMOS.2016.5},
  URN =		{urn:nbn:de:0030-drops-65296},
  doi =		{10.4230/OASIcs.ATMOS.2016.5},
  annote =	{Keywords: autonomous vehicles, platoons, scheduling}
}
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