In this paper, we introduce Factorization Machines (FM) which are a new model class that combines the advantages of Support Vector Machines (SVM) with factorization models. Like SVMs, FMs are a general predictor working with any real valued feature vector. In contrast to SVMs, FMs model all interactions between variables using factorized parameters. Thus they are able to estimate interactions even in problems with huge sparsity (like recommender systems) where SVMs fail. We show that the model equation of FMs can be calculated in linear time and thus FMs can be optimized directly. So unlike nonlinear SVMs, a transformation in the dual form is not necessary and the model parameters can be estimated directly without the need of any support vector in the solution. We show the relationship to SVMs and the advantages of FMs for parameter estimation in sparse settings.On the other hand there are many different factorization models like matrix factorization, parallel factor analysis or specialized models like SVD++, PITF or FPMC. The drawback of these models is that they are not applicable for general prediction tasks but work only with special input data. Furthermore their model equations and optimization algorithms are derived individually for each task. We show that FMs can mimic these models just by specifying the input data (i.e. the feature vectors). This makes FMs easily applicable even for users without expert knowledge in factorization models.

Item recommendation is the task of predicting a personalized ranking on a set of items (e.g. websites, movies, products). In this paper, we investigate the most common scenario with implicit feedback (e.g. clicks, purchases). There are many methods for item recommendation from implicit feedback like matrix factorization (MF) or adaptive knearest-neighbor (kNN). Even though these methods are designed for the item prediction task of personalized ranking, none of them is directly optimized for ranking. In this paper we present a generic optimization criterion BPR-Opt for personalized ranking that is the maximum posterior estimator derived from a Bayesian analysis of the problem. We also provide a generic learning algorithm for optimizing models with respect to BPR-Opt. The learning method is based on stochastic gradient descent with bootstrap sampling. We show how to apply our method to two state-of-the-art recommender models: matrix factorization and adaptive kNN. Our experiments indicate that for the task of personalized ranking our optimization method outperforms the standard learning techniques for MF and kNN. The results show the importance of optimizing models for the right criterion.

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 networkbased 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.

Such systems are particularly useful for entertainment products such as movies, music, and TV shows. Many customers will view the same movie, and each customer is likely to view numerous different movies. Customers have proven willing to indicate their level of satisfaction with particular movies, so a huge volume of data is available about which movies appeal to which customers. Companies can analyze this data to recommend movies to particular customers. RecommendeR system stRategiesBroadly speaking, recommender systems are based on one of two strategies. The content filtering approach creates a profile for each user or product to characterize its nature. For example, a movie profile could include attributes regarding its genre, the participating actors, its box office popularity, and so forth. User profiles might include demographic information or answers provided on a suitable questionnaire. The profiles allow programs to associate users with matching products. Of course, content-based strategies require gathering external information that might not be available or easy to collect.A known successful realization of content filtering is the Music Genome Project, which is used for the Internet radio service Pandora.com. A trained music analyst scores M odern consumers are inundated with choices. Electronic retailers and content providers offer a huge selection of products, with unprecedented opportunities to meet a variety of special needs and tastes. Matching consumers with the most appropriate products is key to enhancing user satisfaction and loyalty. Therefore, more retailers have become interested in recommender systems, which analyze patterns of user interest in products to provide personalized recommendations that suit a user's taste. Because good personalized recommendations can add another dimension to the user experience, e-commerce leaders like Amazon.com and Netflix have made recommender systems a salient part of their websites.

传统的推荐系统面临两个长期存在的障碍，即数据稀疏性和冷启动问题，这些问题促进了跨域建议（CDR）的出现和发展。 CDR的核心思想是利用从其他领域收集的信息来减轻一个域中的两个问题。在过去的十年中，许多努力进行了跨域建议。最近，随着深度学习和神经网络的发展，出现了许多方法。但是，关于CDR的系统调查数量有限，尤其是关于最新提出的方法以及他们解决的建议方案和建议任务。在本调查文件中，我们首先提出了跨域建议的两级分类法，该分类法对不同的建议方案和建议任务进行了分类。然后，我们以结构化的方式介绍并总结了不同建议方案下的现有跨域推荐方法。我们还组织了常用的数据集。我们通过提供有关该领域的几个潜在研究方向来结束这项调查。

Factorization machines (FMs) are a powerful tool for regression and classification in the context of sparse observations, that has been successfully applied to collaborative filtering, especially when side information over users or items is available. Bayesian formulations of FMs have been proposed to provide confidence intervals over the predictions made by the model, however they usually involve Markov-chain Monte Carlo methods that require many samples to provide accurate predictions, resulting in slow training in the context of large-scale data. In this paper, we propose a variational formulation of factorization machines that allows us to derive a simple objective that can be easily optimized using standard mini-batch stochastic gradient descent, making it amenable to large-scale data. Our algorithm learns an approximate posterior distribution over the user and item parameters, which leads to confidence intervals over the predictions. We show, using several datasets, that it has comparable or better performance than existing methods in terms of prediction accuracy, and provide some applications in active learning strategies, e.g., preference elicitation techniques.

随着深度学习技术扩展到现实世界推荐任务，已经开发出许多深度神经网络的协作滤波（CF）模型基于各种神经结构，例如多层的神经架构将用户项目交互项目投影到潜伏特征空间中Perceptron，自动编码器和图形神经网络。然而，大多数现有的协作过滤系统不充分设计用于处理缺失的数据。特别是，为了在训练阶段注入负信号，这些解决方案很大程度上依赖于未观察到的用户项交互，并且简单地将它们视为负实例，这带来了推荐性能下降。为了解决问题，我们开发了一个协作反射增强的AutoEncoder网络（Cranet），它能够探索从观察到和未观察的用户项交互的可转移知识。 Cranet的网络架构由具有反射接收器网络的集成结构和信息融合自动统计器模块形成，其推荐框架具有在互动和非互动项目上编码隐式用户的成对偏好的能力。另外，基于参数正规化的捆绑重量方案旨在对两级颅骨模型进行鲁棒联合训练。我们终于在对应于两个推荐任务的四个不同基准数据集上进行了实验验证了Cranet，以表明，与各种最先进的推荐技术相比，脱叠用户项交互的负信号提高了性能。我们的源代码可在https://github.com/akaxlh/cranet上获得。

由于其适应性和从稀疏数据中学习的能力，分解机（FMS）被广泛用于推荐系统。但是，对于稀疏数据中无处不在的非相互作用特征，现有的FMS只能通过其嵌入的内部产物估算与这些特征相对应的参数。不可否认，他们无法学习这些功能的直接相互作用，这限制了模型的表现力。为此，我们首先提出了受混合启发的MixFM，以生成辅助培训数据以增强FMS。与需要人工成本和专业知识的现有增强策略不同，以收集其他信息，例如位置和领域，这些额外的数据仅由原始的数据组合而没有任何专业知识支持。更重要的是，如果要混合的父样本具有非相互作用的特征，则MixFM将建立其直接相互作用。其次，考虑到MixFM可能会产生冗余甚至有害实例，我们进一步提出了由显着性引导混合措施（称为SMFM）提供动力的新型分解机。在自定义显着性的指导下，SMFM可以生成更具翔实的邻居数据。通过理论分析，我们证明所提出的方法最大程度地减少了概括误差的上限，这对增强FMS具有有益的效果。值得注意的是，我们给出了FM的第一个概括结构，这意味着概括需要更多的数据，并且在足够的表示能力下需要较小的嵌入大小。最后，在五个数据集上进行的大量实验证实，我们的方法优于基准。此外，结果表明，“中毒”混合数据同样对FM变体有益。

Recommender systems provide users with personalized suggestions for products or services. These systems often rely on Collaborating Filtering (CF), where past transactions are analyzed in order to establish connections between users and products. The two more successful approaches to CF are latent factor models, which directly profile both users and products, and neighborhood models, which analyze similarities between products or users. In this work we introduce some innovations to both approaches. The factor and neighborhood models can now be smoothly merged, thereby building a more accurate combined model. Further accuracy improvements are achieved by extending the models to exploit both explicit and implicit feedback by the users. The methods are tested on the Netflix data. Results are better than those previously published on that dataset. In addition, we suggest a new evaluation metric, which highlights the differences among methods, based on their performance at a top-K recommendation task.

在本文中，我们考虑点击率（CTR）预测问题。因子化机器及其变体考虑配对特征交互，但通常我们不会由于高时间复杂度而使用FM进行高阶功能交互。鉴于许多领域的深度神经网络（DNN）的成功，研究人员提出了几种基于DNN的模型来学习高阶功能交互。已广泛用于从功能嵌入到最终登录的功能嵌入的可靠映射，从而广泛使用多层。在本文中，我们的目标是更多地探索这些高阶功能的交互。然而，高阶特征互动值得更加关注和进一步发展。灵感来自计算机愿景中密集连接的卷积网络（DENSENET）的巨大成就，我们提出了一种新颖的模型，称为殷勤基于DENENET的分解机（ADNFM）。 ADNFM可以通过使用前馈神经网络的所有隐藏层作为隐式的高阶功能来提取更全面的深度功能，然后通过注意机制选择主导特征。此外，使用DNN的隐式方式的高阶交互比以明确的方式更具成本效益，例如在FM中。两个真实数据集的广泛实验表明，所提出的模型可以有效地提高CTR预测的性能。

Many existing approaches to collaborative filtering can neither handle very large datasets nor easily deal with users who have very few ratings. In this paper we present the Probabilistic Matrix Factorization (PMF) model which scales linearly with the number of observations and, more importantly, performs well on the large, sparse, and very imbalanced Netflix dataset. We further extend the PMF model to include an adaptive prior on the model parameters and show how the model capacity can be controlled automatically. Finally, we introduce a constrained version of the PMF model that is based on the assumption that users who have rated similar sets of movies are likely to have similar preferences. The resulting model is able to generalize considerably better for users with very few ratings. When the predictions of multiple PMF models are linearly combined with the predictions of Restricted Boltzmann Machines models, we achieve an error rate of 0.8861, that is nearly 7% better than the score of Netflix's own system.

推荐系统是机器学习系统的子类，它们采用复杂的信息过滤策略来减少搜索时间，并向任何特定用户建议最相关的项目。混合建议系统以不同的方式结合了多种建议策略，以从其互补的优势中受益。一些混合推荐系统已经结合了协作过滤和基于内容的方法来构建更强大的系统。在本文中，我们提出了一个混合推荐系统，该系统将基于最小二乘（ALS）的交替正方（ALS）的协作过滤与深度学习结合在一起，以增强建议性能，并克服与协作过滤方法相关的限制，尤其是关于其冷启动问题。本质上，我们使用ALS（协作过滤）的输出来影响深度神经网络（DNN）的建议，该建议结合了大数据处理框架中的特征，上下文，结构和顺序信息。我们已经进行了几项实验，以测试拟议混合体架构向潜在客户推荐智能手机的功效，并将其性能与其他开源推荐人进行比较。结果表明，所提出的系统的表现优于几个现有的混合推荐系统。

多臂匪徒（MAB）提供了一种原则性的在线学习方法，以达到探索和剥削之间的平衡。由于表现出色和反馈学习低，没有学习在多种情况下采取行动，因此多臂匪徒在诸如推荐系统等应用程序中引起了广泛的关注。同样，在推荐系统中，协作过滤（CF）可以说是推荐系统中最早，最具影响力的方法。至关重要的是，新用户和不断变化的推荐项目池是推荐系统需要解决的挑战。对于协作过滤，经典方法是训练模型离线，然后执行在线测试，但是这种方法无法再处理用户偏好的动态变化，即所谓的冷启动。那么，如何在没有有效信息的情况下有效地向用户推荐项目？为了解决上述问题，已经提出了一个基于多臂强盗的协作过滤推荐系统，名为BanditMF。 BANDITMF旨在解决多军强盗算法和协作过滤中的两个挑战：（1）如何在有效信息稀缺的条件下解决冷启动问题以进行协作过滤，（2）强大社会关系域中的强盗算法问题是由独立估计与每个用户相关的未知参数并忽略用户之间的相关性引起的。

因子化机器（FM）是在处理高维稀疏数据时建模成对（二阶）特征交互的普遍存在方法。然而，一方面，FM无法捕获患有组合扩展的高阶特征相互作用，另一方面，考虑每对特征之间的相互作用可能引入噪声和降低预测精度。为了解决问题，我们通过在图形结构中自然表示特征来提出一种新颖的方法图形因子分子机器（GraphFM）。特别地，设计了一种新颖的机制来选择有益特征相互作用，并将它们装配为特征之间的边缘。然后我们所提出的模型将FM的交互功能集成到图形神经网络（GNN）的特征聚合策略中，可以通过堆叠图层模拟图形结构特征上的任意顺序特征交互。关于若干现实世界数据集的实验结果表明了我们提出的方法的合理性和有效性。

大多数现有推荐系统仅基于评级数据，并且他们忽略了可能会增加建议质量的其他信息来源，例如文本评论或用户和项目特征。此外，这些系统的大多数仅适用于小型数据集（数千个观察）并且无法处理大型数据集（具有数百万观察结果）。我们提出了一种推荐人算法，该算法将评级建模技术（即潜在因子模型）与基于文本评论（即潜在Dirichlet分配）的主题建模方法组合，并且我们扩展了算法，使其允许添加额外的用户和项目 - 对系统的特定信息。我们使用具有不同大小的Amazon.com数据集来评估算法的性能，对应于23个产品类别。将建筑模型与四种其他型号进行比较后，我们发现将患有评级的文本评语相结合，导致更好的建议。此外，我们发现为模型添加额外的用户和项目功能会提高其预测精度，这对于中型和大数据集尤其如此。

推荐系统，也称为推荐系统，是一种信息过滤系统，其尝试预测用户的额定值或偏好。本文根据类型，Pearson相关系数，基于KNN的基于KNN的基于KNN的滤波，使用TFIDF和SVD，基于TFIDF和SVD的协作滤波，基于TFIDF和SVD，基于TFIDF和SVD，基于TFIDF和SVD，基于SVD，基于TFIDF和SVD，基于SVD的协作的推荐系统技术来设计和实现完整的电影推荐系统原型。除此之外，我们还提供了一种新颖的想法，适用机器学习技术，基于流派构建电影的集群，然后观察定义了截线的惯性数量。已经描述了本工作中讨论的方法的约束，以及一个策略如何克服另一个策略的缺点。在集团镜头网站上的数据集电影镜片上完成了整个工作，其中包含100836个额定值和3683个TAG应用程序，跨越9742部电影。这些数据是由610年3月29日的610名用户在2018年3月29日和2018年9月24日创建。

To offer accurate and diverse recommendation services, recent methods use auxiliary information to foster the learning process of user and item representations. Many SOTA methods fuse different sources of information (user, item, knowledge graph, tags, etc.) into a graph and use Graph Neural Networks to introduce the auxiliary information through the message passing paradigm. In this work, we seek an alternative framework that is light and effective through self-supervised learning across different sources of information, particularly for the commonly accessible item tag information. We use a self-supervision signal to pair users with the auxiliary information associated with the items they have interacted with before. To achieve the pairing, we create a proxy training task. For a given item, the model predicts the correct pairing between the representations obtained from the users that have interacted with this item and the assigned tags. This design provides an efficient solution, using the auxiliary information directly to enhance the quality of user and item embeddings. User behavior in recommendation systems is driven by the complex interactions of many factors behind the decision-making processes. To make the pairing process more fine-grained and avoid embedding collapse, we propose an intent-aware self-supervised pairing process where we split the user embeddings into multiple sub-embedding vectors. Each sub-embedding vector captures a specific user intent via self-supervised alignment with a particular cluster of tags. We integrate our designed framework with various recommendation models, demonstrating its flexibility and compatibility. Through comparison with numerous SOTA methods on seven real-world datasets, we show that our method can achieve better performance while requiring less training time. This indicates the potential of applying our approach on web-scale datasets.

在本文中，我们提出了一种方法，用于预测社交媒体对等体之间的信任链接，其中一个是在多识别信任建模的人工智能面积。特别是，我们提出了一种数据驱动的多面信任信任建模，该信任建模包括许多不同的特征以进行全面分析。我们专注于展示类似用户的聚类如何实现关键新功能：支持更个性化的，从而为用户提供更准确的预测。在信任感知项目推荐任务中说明，我们在大yelp数据集的上下文中评估所提出的框架。然后，我们讨论如何提高社交媒体的可信关系的检测可以帮助在最近爆发的社交网络环境中支持在线用户的违法行为和谣言的传播。我们的结论是关于一个特别易受资助的用户基础，老年人的反思，以说明关于用户组的推理价值，期望通过通过数据分析获得的洞察力集成已知偏好的一些未来方向。

用户评估包括跨在线平台的大量信息。尽管大多数现有推荐系统都可以缓解稀疏性问题并提高建议质量，但大多数现有推荐系统都忽略了此信息源。这项工作为同时学习项目属性和用户行为提供了一个深层模型。深层合作神经网络（DeepConn）是建议的模型，该模型由两个平行的神经网络组成，这些神经网络在其最终层中相连。其中一个网络专注于从用户提交的评论中学习用户行为，而另一个网络从用户评论中学习项目属性。最重要的是，添加了共享层以连接这两个网络。与分解机方法类似，共享层允许获得的潜在因素和事物相互互动。根据实验发现，在许多数据集上，DeepConn超过所有基线推荐系统。

我们应对嵌入功能的挑战，以改善点击率预测过程。我们选择了三个模型：逻辑回归，分解机和深层分解机，因为我们的基准并提出了五个不同的功能嵌入模块：嵌入缩放，FM嵌入，嵌入编码，NN嵌入，嵌入和嵌入重新加权模块。嵌入模块是改善基线模型特征嵌入的一种方式，并以端到端方式与其余模型参数一起训练。每个模块分别添加到基线模型中，以获得新的增强模型。我们在用于基准点击率预测模型的公共数据集上测试了增强模型的预测性能。我们的结果表明，几个建议的嵌入模块为预测性能提供了重要的提高，而不会大幅度增加训练时间。