3,634 research outputs found
Learning from User Interactions with Rankings: A Unification of the Field
Ranking systems form the basis for online search engines and recommendation
services. They process large collections of items, for instance web pages or
e-commerce products, and present the user with a small ordered selection. The
goal of a ranking system is to help a user find the items they are looking for
with the least amount of effort. Thus the rankings they produce should place
the most relevant or preferred items at the top of the ranking. Learning to
rank is a field within machine learning that covers methods which optimize
ranking systems w.r.t. this goal. Traditional supervised learning to rank
methods utilize expert-judgements to evaluate and learn, however, in many
situations such judgements are impossible or infeasible to obtain. As a
solution, methods have been introduced that perform learning to rank based on
user clicks instead. The difficulty with clicks is that they are not only
affected by user preferences, but also by what rankings were displayed.
Therefore, these methods have to prevent being biased by other factors than
user preference. This thesis concerns learning to rank methods based on user
clicks and specifically aims to unify the different families of these methods.
As a whole, the second part of this thesis proposes a framework that bridges
many gaps between areas of online, counterfactual, and supervised learning to
rank. It has taken approaches, previously considered independent, and unified
them into a single methodology for widely applicable and effective learning to
rank from user clicks.Comment: PhD Thesis of Harrie Oosterhuis defended at the University of
Amsterdam on November 27th 202
Neural Collaborative Filtering
In recent years, deep neural networks have yielded immense success on speech
recognition, computer vision and natural language processing. However, the
exploration of deep neural networks on recommender systems has received
relatively less scrutiny. In this work, we strive to develop techniques based
on neural networks to tackle the key problem in recommendation -- collaborative
filtering -- on the basis of implicit feedback. Although some recent work has
employed deep learning for recommendation, they primarily used it to model
auxiliary information, such as textual descriptions of items and acoustic
features of musics. When it comes to model the key factor in collaborative
filtering -- the interaction between user and item features, they still
resorted to matrix factorization and applied an inner product on the latent
features of users and items. By replacing the inner product with a neural
architecture that can learn an arbitrary function from data, we present a
general framework named NCF, short for Neural network-based Collaborative
Filtering. NCF is generic and can express and generalize matrix factorization
under its framework. To supercharge NCF modelling with non-linearities, we
propose to leverage a multi-layer perceptron to learn the user-item interaction
function. Extensive experiments on two real-world datasets show significant
improvements of our proposed NCF framework over the state-of-the-art methods.
Empirical evidence shows that using deeper layers of neural networks offers
better recommendation performance.Comment: 10 pages, 7 figure
Dense Text Retrieval based on Pretrained Language Models: A Survey
Text retrieval is a long-standing research topic on information seeking,
where a system is required to return relevant information resources to user's
queries in natural language. From classic retrieval methods to learning-based
ranking functions, the underlying retrieval models have been continually
evolved with the ever-lasting technical innovation. To design effective
retrieval models, a key point lies in how to learn the text representation and
model the relevance matching. The recent success of pretrained language models
(PLMs) sheds light on developing more capable text retrieval approaches by
leveraging the excellent modeling capacity of PLMs. With powerful PLMs, we can
effectively learn the representations of queries and texts in the latent
representation space, and further construct the semantic matching function
between the dense vectors for relevance modeling. Such a retrieval approach is
referred to as dense retrieval, since it employs dense vectors (a.k.a.,
embeddings) to represent the texts. Considering the rapid progress on dense
retrieval, in this survey, we systematically review the recent advances on
PLM-based dense retrieval. Different from previous surveys on dense retrieval,
we take a new perspective to organize the related work by four major aspects,
including architecture, training, indexing and integration, and summarize the
mainstream techniques for each aspect. We thoroughly survey the literature, and
include 300+ related reference papers on dense retrieval. To support our
survey, we create a website for providing useful resources, and release a code
repertory and toolkit for implementing dense retrieval models. This survey aims
to provide a comprehensive, practical reference focused on the major progress
for dense text retrieval
A Neural Network Approach to Context-Sensitive Generation of Conversational Responses
We present a novel response generation system that can be trained end to end
on large quantities of unstructured Twitter conversations. A neural network
architecture is used to address sparsity issues that arise when integrating
contextual information into classic statistical models, allowing the system to
take into account previous dialog utterances. Our dynamic-context generative
models show consistent gains over both context-sensitive and
non-context-sensitive Machine Translation and Information Retrieval baselines.Comment: A. Sordoni, M. Galley, M. Auli, C. Brockett, Y. Ji, M. Mitchell,
J.-Y. Nie, J. Gao, B. Dolan. 2015. A Neural Network Approach to
Context-Sensitive Generation of Conversational Responses. In Proc. of
NAACL-HLT. Pages 196-20
Improving End-to-End Sequential Recommendations with Intent-aware Diversification
Sequential Recommendation (SRs) that capture users' dynamic intents by
modeling user sequential behaviors can recommend closely accurate products to
users. Previous work on SRs is mostly focused on optimizing the recommendation
accuracy, often ignoring the recommendation diversity, even though it is an
important criterion for evaluating the recommendation performance. Most
existing methods for improving the diversity of recommendations are not ideally
applicable for SRs because they assume that user intents are static and rely on
post-processing the list of recommendations to promote diversity. We consider
both recommendation accuracy and diversity for SRs by proposing an end-to-end
neural model, called Intent-aware Diversified Sequential Recommendation (IDSR).
Specifically, we introduce an Implicit Intent Mining module (IIM) into SRs to
capture different user intents reflected in user behavior sequences. Then, we
design an Intent-aware Diversity Promoting (IDP) loss to supervise the learning
of the IIM module and force the model to take recommendation diversity into
consideration during training. Extensive experiments on two benchmark datasets
show that IDSR significantly outperforms state-of-the-art methods in terms of
recommendation diversity while yielding comparable or superior recommendation
accuracy
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