Approximation and Online Algorithms: 11th International Workshop, WAOA 2013, Sophia Antipolis, France, September 5-6, 2013, Revised Selected Papers

177 Pages·2014·2.69 MB·English

by  Christos Kaklamanis

Christos Kaklamanis
Kirk Pruhs (Eds.)
7
4 Approximation
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C and Online Algorithms
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11th International Workshop, WAOA 2013
Sophia Antipolis, France, September 5–6, 2013
Revised Selected Papers
123
Lecture Notes in Computer Science 8447
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LancasterUniversity,UK
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CarnegieMellonUniversity,Pittsburgh,PA,USA
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UniversityofSurrey,Guildford,UK
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CornellUniversity,Ithaca,NY,USA
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UniversityofCalifornia,Irvine,CA,USA
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ETHZurich,Switzerland
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WeizmannInstituteofScience,Rehovot,Israel
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UniversityofBern,Switzerland
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IndianInstituteofTechnology,Madras,India
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TUDortmundUniversity,Germany
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UniversityofCalifornia,LosAngeles,CA,USA
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UniversityofCalifornia,Berkeley,CA,USA
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MaxPlanckInstituteforInformatics,Saarbruecken,Germany
Christos Kaklamanis Kirk Pruhs (Eds.)
Approximation
and Online Algorithms
11th International Workshop, WAOA 2013
Sophia Antipolis, France, September 5-6, 2013
Revised Selected Papers
1 3
VolumeEditors
ChristosKaklamanis
UniversityofPatras
ComputerTechnologyInstitute
andPress“Diophantus”
26504Rio,Greece
E-mail:[email protected]
KirkPruhs
UniversityofPittsburgh
210SouthBouquetStreet
Pittsburgh,PA15260,USA
E-mail:[email protected]
ISSN0302-9743 e-ISSN1611-3349
ISBN978-3-319-08000-0 e-ISBN978-3-319-08001-7
DOI10.1007/978-3-319-08001-7
SpringerChamHeidelbergNewYorkDordrechtLondon
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Preface
The 11th Workshop on Approximation and Online Algorithms (WAOA 2013)
focusedonthe designandanalysisofalgorithmsfor online andcomputationally
hardproblems.Both kinds ofproblems havea largenumber ofapplications ina
wide variety of fields. WAOA 2013 took place in Sophia Antipolis, France, dur-
ing September 5–6,2013.The workshopwas part of the ALGO 2013event that
alsohostedESA,WABI,IPEC,ALGOSENSORS,MASSIVE,andATMOS.The
previous WAOA workshops were held in Budapest (2003), Rome (2004), Palma
de Mallorca (2005), Zurich (2006), Eilat (2007), Karlsruhe (2008), Copenhagen
(2009), Liverpool (2010), Saarbru¨cken (2011), and Leicester (2012). The pro-
ceedings of these previous WAOA workshops have appeared as LNCS volumes
2909, 3351, 3879, 4368, 4927, 5426, 5893, 6534, 7164, and 7846, respectively.
TopicsofinterestforWAOA2013were:algorithmicgametheory,algorithmic
trading,coloringandpartitioning,competitiveanalysis,computationaladvertis-
ing, computational finance, cuts and connectivity, geometric problems, graph
algorithms, inapproximability results, mechanism design, natural algorithms,
network design, packing and covering, paradigms for the design and analysis
of approximation and online algorithms, parameterized complexity, real-world
applications, and scheduling problems. In response to the call for papers, we
received 33 submissions. Each submission was reviewed by at least three refer-
ees. The submissions were mainly judged on originality, technical quality, and
relevance to the topics of the conference. Based on the reviews, the Program
Committee selected 14 papers. This volume contains final revised versions of
these papers.
We wouldalsoliketo thank all the authorswho submitted papersto WAOA
2013 as well as Ola Svensson, who gave an invited talk on “New Approaches
forApproximatingTSP.”Furthermore,wearegratefultothelocalorganizersof
ALGO 2013: Fr´ed´eric Cazals, Agn`es Cortell, David Coudert, Olivier Devillers,
Joanna Moulierac, and Monique Teillaud (Chair).
March 2014 Christos Kaklamanis
Kirk Pruhs
Organization
Program Co-chairs
Christos Kaklamanis University of Patras and CTI, Greece
Kirk Pruhs University of Pittsburgh, USA
Program Committee
Vincenzo Bonifaci IASI-CNR, Italy
Niv Buchbinder Tel Aviv University, Israel
Matthias Englert University of Warwick, UK
Leah Epstein University of Haifa, Israel
Bruno Escoffier Universit´e Paris Dauphine, France
Dimitris Fotakis National Technical University of Athens,
Greece
Fabrizio Grandoni University of Lugano, Switzerland
Anupam Gupta Carnegie Mellon University, USA
L(cid:3) ukasz Jez˙ University of Wroc(cid:3)law, Poland
Sungjin Im Duke University, USA
Christos Kaklamanis
(Co-chair) University of Patras and CTI, Greece
Bodo Manthey University of Twente, The Netherlands
Luca Moscardelli University of Chieti-Pescara, Italy
Benjamin Moseley ToyotaTechnologicalInstituteatChicago,USA
Viswanath Nagarajan IBM Research, USA
Debmalya Panigrahi Duke University, USA
Kirk Pruhs
(Co-chair) University of Pittsburgh, USA
Adi Rosen CNRS and Universit´e Paris Diderot, France
Anastasios Sidiropoulos UIUC, USA
Rene Sitters VrijeUniversiteitAmsterdam,TheNetherlands
Kavitha Telikepalli Tata Institute of Fundamental Research, India
Kasturi Varadarajan University of Iowa, USA
Additional Reviewers
Marek Adamczyk Paul Bonsma
Haris Angelidakis Denise Duma
Marcin Bienkowski Alina Ene
VIII Organization
Andreas Galanis Jerome Monnot
Laurent Gourves Katarzyna Paluch
Csanad Imreh Dror Rawitz
Nikos Karanikolas Marc Renault
Robert Kleinberg Bartosz Rybicki
Maria Kyropoulou Alejandro Salinger
Asaf Levin Florian Sikora
Nutan Limaye Aravindan Vijayaraghavan
George Mertzios
Table of Contents
Min-Sum 2-Paths Problems ....................................... 1
Trevor Fenner, Oded Lachish, and Alexandru Popa
Low Dimensional Embeddings of Doubling Metrics ................... 12
Ofer Neiman
Degree-Constrained Graph Orientation: Maximum Satisfaction and
Minimum Violation .............................................. 24
Yuichi Asahiro, Jesper Jansson, Eiji Miyano, and Hirotaka Ono
On the max min vertex cover Problem .......................... 37
Nicolas Boria, Federico Della Croce, and Vangelis Th. Paschos
On Fixed Cost k-Flow Problems ................................... 49
MohammadTaghi Hajiaghayi, Rohit Khandekar, Guy Kortsarz, and
Zeev Nutov
Approximating the Quadratic Knapsack Problem on Special Graph
Classes ......................................................... 61
Ulrich Pferschy and Joachim Schauer
Approximating the Sparsest k-Subgraph in Chordal Graphs ........... 73
R´emi Watrigant, Marin Bougeret, and Rodolphe Giroudeau
Improved Approximation Algorithm for k-Level UFL with Penalties,
a Simplistic View on Randomizing the Scaling Parameter ............. 85
Jaroslaw Byrka, Shanfei Li, and Bartosz Rybicki
Inapproximability Results for Graph Convexity Parameters............ 97
Erika M.M. Coelho, Mitre C. Dourado, and Rudini M. Sampaio
Continuum Armed Bandit Problem of Few Variables in High
Dimensions...................................................... 108
Hemant Tyagi and Bernd Ga¨rtner
Approximability of Connected Factors .............................. 120
Kamiel Cornelissen, Ruben Hoeksma, Bodo Manthey,
N.S. Narayanaswamy, and C.S. Rahul
Reordering Buffer Management with Advice......................... 132
Anna Adamaszek, Marc P. Renault, Adi Ros´en, and Rob van Stee
X Table of Contents
Online Knapsack Revisited........................................ 144
Marek Cygan and L(cid:2) ukasz Jez˙
Counting Approximately-Shortest Paths in Directed Acyclic Graphs.... 156
Matu´ˇs Mihal´ak, Rastislav Sˇra´mek, and Peter Widmayer
Author Index.................................................. 169
Min-Sum 2-Paths Problems
TrevorFenner1,OdedLachish1,andAlexandruPopa2
1 Birkbeck,UniversityofLondon,London,UK
{trevor,oded}@dcs.bbk.ac.uk
2 FacultyofInformatics,MasarykUniversity,Brno,CzechRepublic
[email protected]
Abstract. AnorientationofanundirectedgraphGisadirectedgraphobtained
byreplacingeachedge{u,v}ofGbyexactlyoneofthearcs(u,v)or(v,u).In
themin-sumk-pathsorientationproblem,theinputisanundirectedgraphGand
orderedpairs(si,ti),wherei∈{1,2,...,k}.Thegoalistofindanorientation
ofGthatminimizesthesumovereveryi∈{1,2,...,k}ofthedistancefromsi
toti.
Inthemin-sumkedge-disjointpathsproblemtheinputisthesame,however
thegoal istofindforeveryi ∈ {1,2,...,k}apathbetweensi andti sothat
thesepathsareedge-disjointandthesumoftheirlengthsisminimum.Notethat,
for every fixed k ≥ 2, the question of NP-hardness for the min-sum k-paths
orientation problem and themin-sum k edge-disjoint paths problem havebeen
open for more than two decades. We study the complexity of these problems
whenk=2.
WeexhibitaPTASforthemin-sum2-pathsorientationproblem.Aby-product
ofthisPTASisareductionfromthemin-sum2-pathsorientationproblemtothe
min-sum2edge-disjoint pathsproblem. Theimplicationsofthisreduction are:
(i)anNP-hardnessproofforthemin-sum2-pathsorientationproblemyieldsan
NP-hardnessproof forthemin-sum2edge-disjointpathsproblem,and(ii)any
approximationalgorithmforthemin-sum2edge-disjointpathsproblemcanbe
usedtoconstructanapproximationalgorithmforthemin-sum2-pathsorientation
problemwiththesameapproximationguaranteeandonlyanadditivepolynomial
increaseintherunningtime.
1 Introduction
Incommunications,Multihomingisthe processofcommunicatingthroughmorethan
one connection. The goal is to increase communication reliability. Now imagine that
eachconnectionmustbemadebetweentwodistinctentities,forexample,ifacustomer
hasnumerousinternetproviders,eachwithadistinctentrypointthatrequiresaconnec-
tiontoadistinctend-point,see[1,8].Thisisthecasewedealwithhere.
Inordertooptimizereliabilitywhenusingmultipleconnectionsanaturalgoalisthat
thechannelsaredisjoint.Wemodeltheproblemofdeterminingwhethersuchchannels
existwiththek edge-disjointpathsproblem,wheretheinputisaninstanceconsisting
ofagraphandpairsofvertices{s ,t },wherei∈{1,2,...,k},andthegoalistofind
i i
kedge-disjointpathsbetweenthekpairs{s ,t }.RobertsonandSeymourprovedin[7]
i i
that,forfixedk,thisproblemisinP.
C.KaklamanisandK.Pruhs(Eds.):WAOA2013,LNCS8447,pp.1–11,2014.
(cid:2)c SpringerInternationalPublishingSwitzerland2014