2,877 research outputs found
Automated Machine Learning for Deep Recommender Systems: A Survey
Deep recommender systems (DRS) are critical for current commercial online
service providers, which address the issue of information overload by
recommending items that are tailored to the user's interests and preferences.
They have unprecedented feature representations effectiveness and the capacity
of modeling the non-linear relationships between users and items. Despite their
advancements, DRS models, like other deep learning models, employ sophisticated
neural network architectures and other vital components that are typically
designed and tuned by human experts. This article will give a comprehensive
summary of automated machine learning (AutoML) for developing DRS models. We
first provide an overview of AutoML for DRS models and the related techniques.
Then we discuss the state-of-the-art AutoML approaches that automate the
feature selection, feature embeddings, feature interactions, and system design
in DRS. Finally, we discuss appealing research directions and summarize the
survey
Personalized Ranking in eCommerce Search
We address the problem of personalization in the context of eCommerce search.
Specifically, we develop personalization ranking features that use in-session
context to augment a generic ranker optimized for conversion and relevance. We
use a combination of latent features learned from item co-clicks in historic
sessions and content-based features that use item title and price.
Personalization in search has been discussed extensively in the existing
literature. The novelty of our work is combining and comparing content-based
and content-agnostic features and showing that they complement each other to
result in a significant improvement of the ranker. Moreover, our technique does
not require an explicit re-ranking step, does not rely on learning user
profiles from long term search behavior, and does not involve complex modeling
of query-item-user features. Our approach captures item co-click propensity
using lightweight item embeddings. We experimentally show that our technique
significantly outperforms a generic ranker in terms of Mean Reciprocal Rank
(MRR). We also provide anecdotal evidence for the semantic similarity captured
by the item embeddings on the eBay search engine.Comment: Under Revie
LambdaOpt: Learn to Regularize Recommender Models in Finer Levels
Recommendation models mainly deal with categorical variables, such as
user/item ID and attributes. Besides the high-cardinality issue, the
interactions among such categorical variables are usually long-tailed, with the
head made up of highly frequent values and a long tail of rare ones. This
phenomenon results in the data sparsity issue, making it essential to
regularize the models to ensure generalization. The common practice is to
employ grid search to manually tune regularization hyperparameters based on the
validation data. However, it requires non-trivial efforts and large computation
resources to search the whole candidate space; even so, it may not lead to the
optimal choice, for which different parameters should have different
regularization strengths. In this paper, we propose a hyperparameter
optimization method, LambdaOpt, which automatically and adaptively enforces
regularization during training. Specifically, it updates the regularization
coefficients based on the performance of validation data. With LambdaOpt, the
notorious tuning of regularization hyperparameters can be avoided; more
importantly, it allows fine-grained regularization (i.e. each parameter can
have an individualized regularization coefficient), leading to better
generalized models. We show how to employ LambdaOpt on matrix factorization, a
classical model that is representative of a large family of recommender models.
Extensive experiments on two public benchmarks demonstrate the superiority of
our method in boosting the performance of top-K recommendation.Comment: Accepted by KDD 201
Continuous Input Embedding Size Search For Recommender Systems
Latent factor models are the most popular backbones for today's recommender
systems owing to their prominent performance. Latent factor models represent
users and items as real-valued embedding vectors for pairwise similarity
computation, and all embeddings are traditionally restricted to a uniform size
that is relatively large (e.g., 256-dimensional). With the exponentially
expanding user base and item catalog in contemporary e-commerce, this design is
admittedly becoming memory-inefficient. To facilitate lightweight
recommendation, reinforcement learning (RL) has recently opened up
opportunities for identifying varying embedding sizes for different
users/items. However, challenged by search efficiency and learning an optimal
RL policy, existing RL-based methods are restricted to highly discrete,
predefined embedding size choices. This leads to a largely overlooked potential
of introducing finer granularity into embedding sizes to obtain better
recommendation effectiveness under a given memory budget. In this paper, we
propose continuous input embedding size search (CIESS), a novel RL-based method
that operates on a continuous search space with arbitrary embedding sizes to
choose from. In CIESS, we further present an innovative random walk-based
exploration strategy to allow the RL policy to efficiently explore more
candidate embedding sizes and converge to a better decision. CIESS is also
model-agnostic and hence generalizable to a variety of latent factor RSs,
whilst experiments on two real-world datasets have shown state-of-the-art
performance of CIESS under different memory budgets when paired with three
popular recommendation models.Comment: To appear in SIGIR'2
AutoMLP: Automated MLP for Sequential Recommendations
Sequential recommender systems aim to predict users' next interested item
given their historical interactions. However, a long-standing issue is how to
distinguish between users' long/short-term interests, which may be
heterogeneous and contribute differently to the next recommendation. Existing
approaches usually set pre-defined short-term interest length by exhaustive
search or empirical experience, which is either highly inefficient or yields
subpar results. The recent advanced transformer-based models can achieve
state-of-the-art performances despite the aforementioned issue, but they have a
quadratic computational complexity to the length of the input sequence. To this
end, this paper proposes a novel sequential recommender system, AutoMLP, aiming
for better modeling users' long/short-term interests from their historical
interactions. In addition, we design an automated and adaptive search algorithm
for preferable short-term interest length via end-to-end optimization. Through
extensive experiments, we show that AutoMLP has competitive performance against
state-of-the-art methods, while maintaining linear computational complexity.Comment: Accepted by WWW'2
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