Creativity is the heart and soul of advertising services. Effective creatives can create a win-win scenario: advertisers each target users and achieve marketing objectives more effectively, users more quickly find products of interest, and platforms generate more advertising revenue. With the advent of AI-Generated Content, advertisers now can produce vast amounts of creative content at a minimal cost. The current challenge lies in how advertising systems can select the most pertinent creative in real-time for each user personally. Existing methods typically perform serial ranking of ads or creatives, limiting the creative module in terms of both effectiveness and efficiency. In this paper, we propose for the first time a novel architecture for online parallel estimation of ads and creatives ranking, as well as the corresponding offline joint optimization model. The online architecture enables sophisticated personalized creative modeling while reducing overall latency. The offline joint model for CTR estimation allows mutual awareness and collaborative optimization between ads and creatives. Additionally, we optimize the offline evaluation metrics for the implicit feedback sorting task involved in ad creative ranking. We conduct extensive experiments to compare ours with two state-of-the-art approaches. The results demonstrate the effectiveness of our approach in both offline evaluations and real-world advertising platforms online in terms of response time, CTR, and CPM.

Thompson Sampling (TS) is an effective way to deal with the exploration-exploitation dilemma for the multi-armed (contextual) bandit problem. Due to the sophisticated relationship between contexts and rewards in real- world applications, neural networks are often preferable to model this relationship owing to their superior representation capacity. In this paper, we study the problem of combining neural networks with TS in a plug-and-play manner. The basic idea is to maintain a posterior distribution over the reward mean relying on the prediction and the deep representation of the neural network for any given context. Specifically, our proposed algorithm, PlugTS (Pluggable deep Thompson Sampling), introduces no change into the network training process, but only requires one additional sampling stage during serving - sampling from a univariate Gaussian distribution (by maintaining a positive definite matrix). Theoretically, we prove that PlugTS achieves an regret bound, which matches the state-of-the-art neural network-based TS, while PlugTS enjoys much lower computational overhead for each iteration. Experimental results on public datasets among traditional classification and recommendation tasks validate the effectiveness and efficiency of PlugTS. Furthermore, it is inspiring for real-world applications that a simplified version of PlugTS has been deployed in an industrial advertising recommender system of one of the world's largest e-commerce platforms, JD.com, achieving significant improvement in both RPM (Revenue Per Mille) and CTR (Click-Through Rate) in online A/B testing. The appendix and code are available at https://github.com/adsturing/PlugTS.

Organic recommendation and advertising recommendation usually coexist on e-commerce platforms. In this paper, we study the problem of utilizing data from organic recommendation to reinforce click-through rate prediction in advertising scenarios from a multi-view learning perspective. We propose a novel method, termed LOVF (Layered Organic View Fusion). LOVF implements a multi-view fusion mechanism - for each advertising instance, LOVF derives deep representations layer-by-layer from the organic recommendation view and these deep representations are then fused into the corresponding vanilla representations of the advertising view. Extensive experiments across a variety of backbones demonstrate LOVF's generality, effectiveness and efficiency on a new real-world production dataset. The dataset encompasses data from both the organic recommendation and advertising scenarios. Notably, LOVF has been successfully deployed in the advertising recommender system of JD.com, which is one of the world's largest e-commerce platforms; online A/B testing shows that LOVF achieves impressive improvement on advertising clicks and revenue. Our code and dataset are available at https://github.com/adsturing/lovf for facilitating further research.

Click-through rate (CTR) prediction plays a crucial role in sponsored search advertising (search ads). User click behavior usually showcases strong comparison patterns among relevant/competing items within the user awareness. Explicit user awareness could be characterized by user behavior sequence modeling, which however suffers from issues such as cold start, behavior noise and hidden channels. Instead, in this paper, we study the problem of modeling implicit user awareness about relevant/competing items. We notice that candidate items of the CTR prediction model could play as surrogates for relevant/competing items within the user awareness. Motivated by this finding, we propose a novel framework, named CIM (Candidate Item Modeling), to characterize users’ awareness on candidate items. CIM introduces an additional module to encode candidate items into a context vector and therefore is plug-and-play for existing neural network-based CTR prediction models. Offline experiments on a ten-billion-scale production dataset collected from the real traffic of a search advertising system, together with the corresponding online A/B testing, demonstrate CIM’s superior performance. Notably, CIM has been deployed in production at JD.com, serving the main traffic of hundreds of millions of users, which shows great application value. Our code and dataset are available at https://github.com/kaifuzheng/cim.

Click-through rate (CTR) prediction based on deep neural networks has made significant progress in recommendation systems. However, these methods often suffer from CTR underestimation due to insufficient impressions for long-tail items. When formalizing CTR prediction as a contextual bandit problem, exploration methods provide a natural solution addressing this issue. In this paper, we first benchmark state-of-the-art exploration methods in the recommendation system setting. We find that the combination of gradient-based uncertainty modeling and Thompson Sampling achieves a significant advantage. On the basis of the benchmark, we further propose a general enhancement strategy, Underestimation Refinement (UR), which explicitly incorporates the prior knowledge that insufficient impressions likely leads to CTR underestimation. This strategy is applicable to almost all the existing exploration methods. Experimental results validate UR's effectiveness, achieving consistent improvement across all baseline exploration methods.

Metric learning is an important family of algorithms for classification and similarity search, but the robustness of learned metrics against small adversarial perturbations is less studied. In this paper, we show that existing metric learning algorithms, which focus on boosting the clean accuracy, can result in metrics that are less robust than the Euclidean distance. To overcome this problem, we propose a novel metric learning algorithm to find a Mahalanobis distance that is robust against adversarial perturbations, and the robustness of the resulting model is certifiable. Experimental results show that the proposed metric learning algorithm improves both certified robust errors and empirical robust errors (errors under adversarial attacks). Furthermore, unlike neural network defenses which usually encounter a trade-off between clean and robust errors, our method does not sacrifice clean errors compared with previous metric learning methods.

Matrix concentration inequalities have attracted much attention in diverse applications such as linear algebra, statistical estimation, combinatorial optimization, etc. In this paper, we present new Bernstein concentration inequalities depending only on the first moments of random matrices, whereas previous Bernstein inequalities are heavily relevant to the first and second moments. Based on those results, we analyze the empirical risk minimization in the presence of label noise. We find that many popular losses used in risk minimization can be decomposed into two parts, where the first part won't be affected and only the second part will be affected by noisy labels. We show that the influence of noisy labels on the second part can be reduced by our proposed LICS (Labeled Instance Centroid Smoothing) approach. The effectiveness of the LICS algorithm is justified both theoretically and empirically.