Hard computational problems are often solvable by multiple algorithms that each perform well on different problem instances. We describe techniques for building an algorithm portfolio that can outperform its constituent algorithms, just as the aggregate classifiers learned by boosting outperform the classifiers of which they are composed. We also provide a method for generating test distributio...

Combinatorial Auctions are an attractive application of intelligent agents; their applications are countless and are shown to provide good revenues. On the other hand, one of the issues they raise is the computational complexity of the solving process (the Winner Determination Problem, WDP), that delayed their practical use. Recently, efficient solvers have been applied to the WDP, so the frame...

We introduce an auction design and computational methods to determine core payments for large markets with many objects such as the market for TV ads. Bidder optimal, core-selecting auctions have been introduced in spectrum auctions worldwide as a means to set incentives for truthful bidding, but at the same time avoid the problems of the Vickrey-Clarke-Groves mechanism. Many real-world markets...

Winner determination is one of the main challenges in combinatorial auctions. However, not much work has been done to solve this problem in the case of reverse auctions using evolutionary techniques. This has motivated us to propose an improvement of a genetic algorithm based method, we have previously proposed, to address two important issues in the context of combinatorial reverse auctions: d...

A combinatorial auction is an auction where the bidders have the choice to bid on bundles of items. The WDP in combinatorial auctions is the problem of finding winning bids that maximize the auctioneer’s revenue under the constraint that each item can be allocated to at most one bidder. The WDP is known as an NP-hard problem with practical applications like electronic commerce, production manag...

Preferences can be aggregated using voting rules. We consider here the family of rules which perform a sequence of pairwise majority comparisons between two candidates. The winner thus depends on the chosen sequence of comparisons, which can be represented by a binary tree. We address the difficulty of computing candidates that win for some trees, and then introduce and study the notion of fair...

Combinatorial auctions, i.e. auctions where bidders can bid on combinations of items, tend to lead to more eecient allocations than traditional auctions in multi-item auctions where the agents' valuations of the items are not additive. However, determining the winners so as to maximize revenue is NP-complete. First, existing approaches for tackling this problem are reviewed: exhaustive enu-mera...

Computing the winners of an election is an important subtask in voting and preference aggregation. The declarative nature of answer-set programming (ASP) and the performance of state-of-the-art solvers render ASP very well-suited to tackle this problem. In this work we present a novel, reduction-based approach for a variety of voting rules, ranging from tractable cases to problems harder than N...