Online Ad assignment with free disposal

Jon Feldman, Nitish Korula, Vahab Mirrokni, S. Muthukrishnan, Martin Pál

    Research output: Chapter in Book/Report/Conference proceedingConference contribution


    We study an online weighted assignment problem with a set of fixed nodes corresponding to advertisers and online arrival of nodes corresponding to ad impressions. Advertiser a has a contract for n(a) impressions, and each impression has a set of weighted edges to advertisers. The problem is to assign the impressions online so that while each advertiser a gets n(a) impressions, the total weight of edges assigned is maximized. Our insight is that ad impressions allow for free disposal, that is, advertisers are indifferent to, or prefer being assigned more than n(a) impressions without changing the contract terms. This means that the value of an assignment only includes the n(a) highest-weighted items assigned to each node a. With free disposal, we provide an algorithm for this problem that achieves a competitive ratio of 1-1/e against the offline optimum, and show that this is the best possible ratio. We use a primal/dual framework to derive our results, applying a novel exponentially-weighted dual update rule. Furthermore, our algorithm can be applied to a general set of assignment problems including the ad words problem as a special case, matching the previously known 1-1/e competitive ratio.

    Original languageEnglish (US)
    Title of host publicationInternet and Network Economics - 5th International Workshop, WINE 2009, Proceedings
    Number of pages12
    StatePublished - 2009
    Event5th International Workshop on Internet and Network Economics, WINE 2009 - Rome, Italy
    Duration: Dec 14 2009Dec 18 2009

    Publication series

    NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
    Volume5929 LNCS
    ISSN (Print)0302-9743
    ISSN (Electronic)1611-3349


    Conference5th International Workshop on Internet and Network Economics, WINE 2009

    ASJC Scopus subject areas

    • Theoretical Computer Science
    • General Computer Science


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