Alapfogalmak
The core message of this paper is to propose a Markov Decision Process (MDP) model to capture the user's response to the quality of ads, with the objective of maximizing the long-term discounted revenue for the ad auction platform. The authors characterize the optimal mechanism as a Myerson's auction with a notion of modified virtual value, and also propose a simple second-price auction with personalized reserves that achieves a constant-factor approximation to the optimal long-term revenue.
Kivonat
The paper proposes a new Markov Decision Process (MDP) model to capture the user's response to the quality of ads in ad auctions. The key idea is to model the user state as a user-specific click-through rate (CTR) that changes in the next round based on the set of ads shown to the user in the current round.
The authors first characterize the optimal mechanism for this MDP setting as a Myerson's auction with a notion of modified virtual value, which takes into account both the current revenue and the future impact of showing the ad to the user. This optimal mechanism balances the short-term revenue considerations and the long-term effects on the user's propensity to click ads.
The authors then propose a simple second-price auction with personalized reserves as an approximation to the optimal mechanism. They show that this simple mechanism can achieve a constant-factor approximation to the optimal long-term discounted revenue, while maintaining the same user state transitions as the optimal mechanism. The key technical challenge is to design the personalized reserves in a way that controls the user state transitions and trades off the current round revenue with the long-term impact.
Finally, the authors provide experimental results comparing various natural auctions that incorporate user state.
Statisztikák
The paper does not contain any explicit numerical data or statistics. It focuses on the theoretical analysis of the proposed MDP model and auction mechanisms.
Idézetek
"We propose a new Markov Decision Process (MDP) model for ad auctions to capture the user response to the quality of ads, with the objective of maximizing the long-term discounted revenue."
"The long-term revenue-optimal auction takes a recognizable form. A seminal result due to Myerson [23] showed that, when bidders' valuations are drawn from some regular distribution, the revenue optimal auction maximizes virtual welfare, which is a function of both the bid and the value distribution of each bidder. In our model, we define the notion of a modified virtual welfare which consists of the original virtual welfare plus a correction term that takes into account the long-term impact of showing a particular set of ads."
"There is indeed a version of a second-price auction with personalized reserves which provides a constant factor approximation to the long-term revenue-optimal auction."