Motivated by online advertising auctions, we study auction design in repeated
auctions played by simple Artificial Intelligence algorithms (Q-learning). We
find that first-price auctions with no additional feedback lead to
tacit-collusive outcomes (bids lower than values), while second-price auctions
do not. We show that the difference is driven by the incentive in first-price
auctions to outbid opponents by just one bid increment. This facilitates
re-coordination on low bids after a phase of experimentation. We also show that
providing information about lowest bid to win, as introduced by Google at the
time of switch to first-price auctions, increases competitiveness of auctions.

本文探究了重复拍卖中的拍卖设计，其中通过简单人工智能算法 (Q-learning) 进行拍卖。我们发现，在没有额外反馈的情况下，第一价格拍卖会导致默认勾结结果（竞投低于价值），而第二价格拍卖则不会。我们展示了这种差异是由第一价格拍卖中超越竞争者一个出价单位的刺激所驱动的。这在经过试验阶段之后便有助于实现对低竞标的重新协调。同时，我们还发现，谷歌在转向第一价格拍卖时引入的有关获胜的最低竞标的信息提供，增加了拍卖的竞争度。

人工智能与拍卖设计

Artificial Intelligence and Auction Design

In programmatic advertising, ad slots are usually sold using second-price
(SP) auctions in real-time. The highest bidding advertiser wins but pays only
the second-highest bid (known as the winning price). In SP, for a single item,
the dominant strategy of each bidder is to bid the true value from the bidder's
perspective. However, in a practical setting, with budget constraints, bidding
the true value is a sub-optimal strategy. Hence, to devise an optimal bidding
strategy, it is of utmost importance to learn the winning price distribution
accurately. Moreover, a demand-side platform (DSP), which bids on behalf of
advertisers, observes the winning price if it wins the auction. For losing
auctions, DSPs can only treat its bidding price as the lower bound for the
unknown winning price. In literature, typically censored regression is used to
model such partially observed data. A common assumption in censored regression
is that the winning price is drawn from a fixed variance (homoscedastic)
uni-modal distribution (most often Gaussian). However, in reality, these
assumptions are often violated. We relax these assumptions and propose a
heteroscedastic fully parametric censored regression approach, as well as a
mixture density censored network. Our approach not only generalizes censored
regression but also provides flexibility to model arbitrarily distributed
real-world data. Experimental evaluation on the publicly available dataset for
winning price estimation demonstrates the effectiveness of our method.
Furthermore, we evaluate our algorithm on one of the largest demand-side
platforms and significant improvement has been achieved in comparison with the
baseline solutions.

本文提出了一个基于未完全观测数据的 heteroscedastic fully parametric censored regression 方法和混合密度 censored 网络，用于估计广告拍卖中的赢价分布，并在实验上证明了该方法的有效性。

实时竞价中可扩展的竞价预测

Scalable Bid Landscape Forecasting in Real-time Bidding

Second-price auctions with reserve play a critical role for modern search
engine and popular online sites since the revenue of these companies often
directly de- pends on the outcome of such auctions. The choice of the reserve
price is the main mechanism through which the auction revenue can be influenced
in these electronic markets. We cast the problem of selecting the reserve price
to optimize revenue as a learning problem and present a full theoretical
analysis dealing with the complex properties of the corresponding loss
function. We further give novel algorithms for solving this problem and report
the results of several experiments in both synthetic and real data
demonstrating their effectiveness.

本研究运用学习算法优化电子市场上二价拍卖的保留价，实现收益最大化。经过理论探讨与实验展示，证明该算法有效性高。