# Florian SchoppmannStanford University | SU · Department of Computer Science

Florian Schoppmann

Ph.D. in Computer Science (German degree: Dr. rer. nat.)

## About

18

Publications

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## Publications

Publications (18)

MADlib is a free, open source library of in-database analytic methods. It
provides an evolving suite of SQL-based algorithms for machine learning, data
mining and statistics that run at scale within a database engine, with no need
for data import/export to other tools. The goal is for MADlib to eventually
serve a role for scalable database systems...

MADlib is a free, open-source library of in-database analytic methods. It provides an evolving suite of SQL-based algorithms for machine learning, data mining and statistics that run at scale within a database engine, with no need for data import/export to other tools. The goal is for MADlib to eventually serve a role for scalable database systems...

We resolve the worst-case price of anarchy (POA) of atomic splittable congestion games. Prior to this work, no tight bounds on the POA in such games were known, even for the simplest non-trivial special case of affine cost functions. We make two distinct contributions. On the upper-bound side, we define the framework of "local smoothness", which re...

We show exact values for the worst-case price of anarchy in weighted and unweighted (atomic unsplittable) congestion games, provided that all cost functions are bounded-degree polynomials with nonnegative coefficients. The given values also hold for weighted and unweighted network congestion games.

This work initiates the study of cost-sharing mechanisms that, in addition to the usual incentive compatibility conditions, make it disadvantageous for the users to employ pseudonyms. We show that this is possible only if all serviced users pay the same price, which implies that such mechanisms do not exist even for certain subadditive cost functio...

In a cost-sharing problem, finitely many players have an unknown preference for some public excludable good (service), and the task is to determine which players to serve and how to distribute the in- curred cost. Therefore, incentive-compatible mechanisms are sought that elicit truthful bids, charge prices that recover the cost, and are economical...

In a Voronoi game, there is a finite number of players who each chooses a point in some metric space. A player's utility is the total measure of all points that are closer to him than to any other player, where points equidistant to several players are split up evenly among the closest players. In a recent paper, Dürr and Thang (2007) considered di...

In the context of scheduling, we study social cost efficiency for a cost-sharing problem in which the service provider's cost is determined by the makespan of the served agents' jobs. For identical machines, we give surprisingly simple cross-monotonic cost-sharing methods that achieve the essentially best efficiency Moulin mechanisms can guarantee....

In the context of general demand cost sharing, we present the first group-strategyproof mechanisms for the metric fault tolerant uncapacitated facility location problem. They are \((3 \ensuremath{L})\)-budget-balanced and \((3 \ensuremath{L} \cdot (1 + \mathcal H_n))\)-efficient, where \(\ensuremath{L}\) is the maximum service level and n is the nu...

We provide a collection of new upper and lower bounds on the price of anarchy for singleton congestion games. In our study, we distinguish between restricted and unrestricted strategy sets, between weighted and unweighted player weights,
and between linear and polynomial latency functions.

A common modeling assumption in the realm of cost sharing is that players persuade each other to jointly submit false bids if none of the members of such a coalition loses utility and at least one gains. In order to counteract this kind of manipulation, the service provider could employ group-strategyproof (GSP) mechanisms that elicit truthful bids...

Assuming strict consumer sovereignty (CS*), when can cost-sharing mechanisms simultaneously be group-strategyproof (GSP) and β-budget-balanced (β-BB)? Moulin mechanisms are GSP and 1-BB for submodular costs. We overcome the submodularity requirement and instead consider arbitrary—yet symmetric—costs:
Already for 4 players, we show that symmetry of...

We look at the scenario of having to route a continuous rate of traffic from a source node to a sink node in a network, where the objective is to maximize throughput. This is of interest, e.g., for providers of streaming content in communication networks. The overall path latency, which was relevant in other non-cooperative network routing games su...

We show exact values for the price of anarchy of weighted and unweighted congestion games with polynomial latency functions.
The given values also hold for weighted and unweighted network congestion games.

In a cost-sharing problem, finitely many players have an unknown valuation for some service, and the task is to determine which players to serve and how to distribute the incurred cost. Incentive-compatible mechanisms are sought that elicit truthful valuations, charge prices that recover the cost, and are economically ecient in that they reasonably...

Zusammenfassung Große Kommunikations-und Verkehrsnetze sind Systeme, in denen es zur Routenplanung oftmals keine zentrale Regulierungsinstanz gibt. Eine solche Instanz kann sogar inhärent unmöglich sein, wenn Benutzer – wie etwa in Ver-kehrsnetzen – frei entscheiden dürfen. Stattdessen ist oftmals die Annahme gerechtfertigt, dass die Teilnehmer eig...

Wie kann man ein System so gestalten, dass sich autonome eigennützige Spieler in "wünschenswerter" Weise verhalten werden? In dieser Dissertation betrachten wir diese Frage im Kontext von Kostenaufteilungs-Problemen, bei denen endlich viele Spieler eine unbekannte Wertschätzung für einen nicht-rivalen aber ausschließbaren Service (z.B. Netzwerk-Kon...