Online packet scheduling with bounded delay and lookahead

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F19%3A10404878" target="_blank" >RIV/00216208:11320/19:10404878 - isvavai.cz</a>

Výsledek na webu

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=A.kn0WUlc5" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=A.kn0WUlc5</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.tcs.2019.01.013" target="_blank" >10.1016/j.tcs.2019.01.013</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Online packet scheduling with bounded delay and lookahead

Popis výsledku v původním jazyce

We study the online bounded delay packet scheduling problem (PacketScheduling), where packets of unit size arrive at a router over time and need to be transmitted over a network link. Each packet has two attributes: a non-negative weight and a deadline for its transmission. The objective is to maximize the total weight of the transmitted packets. This problem has been well studied in the literature; yet currently the best published upper bound is 1.828 [8], still quite far from the best lower bound of phi approximate to 1.618 [11,2,6]. In the variant of PacketScheduling with s-bounded instances, each packet can be scheduled in at most s consecutive slots, starting at its release time. The lower bound of phi applies even to the special case of 2-bounded instances, and a phi-competitive algorithm for 3-bounded instances was given in [5]. Improving that result, and addressing a question posed by Goldwasser [9], we present a phi-competitive algorithm for 4 bounded instances. We also study a variant of PacketScheduling where an online algorithm has the additional power of 1- lookahead, knowing at time t which packets will arrive at time t + 1. For PacketScheduling with 1-lookahead restricted to 2-bounded instances, we present an online algorithm with competitive ratio 1/2 (root 13-1) approximate to 1.303 and we prove a nearly tight lower bound of 1/4 (1 + root 17) approximate to 1.281. In fact, our lower bound result is more general: using only 2-bounded instances, for any integer l &gt;= 0 we prove a lower bound of 1/2(l+1) (1+root 5+8l+4l(2)) for online algorithms with l-lookahead, i.e., algorithms that at time t can see all packets arriving by time t + l. Finally, for non-restricted instances we show a lower bound of 1.25 for randomized algorithms with l-lookahead, for any l &gt;= 0.

Název v anglickém jazyce

Online packet scheduling with bounded delay and lookahead

Popis výsledku anglicky

We study the online bounded delay packet scheduling problem (PacketScheduling), where packets of unit size arrive at a router over time and need to be transmitted over a network link. Each packet has two attributes: a non-negative weight and a deadline for its transmission. The objective is to maximize the total weight of the transmitted packets. This problem has been well studied in the literature; yet currently the best published upper bound is 1.828 [8], still quite far from the best lower bound of phi approximate to 1.618 [11,2,6]. In the variant of PacketScheduling with s-bounded instances, each packet can be scheduled in at most s consecutive slots, starting at its release time. The lower bound of phi applies even to the special case of 2-bounded instances, and a phi-competitive algorithm for 3-bounded instances was given in [5]. Improving that result, and addressing a question posed by Goldwasser [9], we present a phi-competitive algorithm for 4 bounded instances. We also study a variant of PacketScheduling where an online algorithm has the additional power of 1- lookahead, knowing at time t which packets will arrive at time t + 1. For PacketScheduling with 1-lookahead restricted to 2-bounded instances, we present an online algorithm with competitive ratio 1/2 (root 13-1) approximate to 1.303 and we prove a nearly tight lower bound of 1/4 (1 + root 17) approximate to 1.281. In fact, our lower bound result is more general: using only 2-bounded instances, for any integer l &gt;= 0 we prove a lower bound of 1/2(l+1) (1+root 5+8l+4l(2)) for online algorithms with l-lookahead, i.e., algorithms that at time t can see all packets arriving by time t + l. Finally, for non-restricted instances we show a lower bound of 1.25 for randomized algorithms with l-lookahead, for any l &gt;= 0.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10201 - Computer sciences, information science, bioinformathics (hardware development to be 2.2, social aspect to be 5.8)

Projekt

<a href="/cs/project/GA17-09142S" target="_blank" >GA17-09142S: Moderní algoritmy: Nové výzvy komplexních dat</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2019

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Theoretical Computer Science

ISSN

0304-3975

e-ISSN

—

Svazek periodika

776

Číslo periodika v rámci svazku

July 2019

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

19

Strana od-do

95-113

Kód UT WoS článku

000470948700006

EID výsledku v databázi Scopus

2-s2.0-85060101147