Session-based Recommendation Research Articles

Advancing Session-Based Recommendations with Atten-Mixer+: Dynamic and Adaptive Multi-Level Intent Mining

Session-based recommendation (SBR) systems, traditionally reliant on complex graph neural networks (GNNs), often face challenges with marginal performance improvements despite increased model complexity. In this paper, we dissect the classical GNN-based SBR models and empirically find that the sophisticated GNN propagations might be redundant, given the readout module plays a significant role in GNN-based models. Based on this observation, we introduce Atten-Mixer+, an advanced iteration of our previously developed Multi-Level Attention Mixture Network (Atten-Mixer). Atten-Mixer+ forgoes GNN propagation in favor of a dynamic and adaptive readout process, tailored to the unique characteristics of each session. Different from the vanilla version, Atten-Mixer+ features the Adaptive Intent Scaler (AIS) layer, which dynamically determines the depth of multi-level user intent analysis, and a soft allocation approach for generating user intent queries across entire user interaction sequences. This innovative design allows Atten-Mixer+ to capture a nuanced and comprehensive understanding of user behaviors, overcoming the limitations of fixed-length analysis. Empirical evaluations on benchmark datasets highlight Atten-Mixer+'s superior efficiency and effectiveness, marking a significant step forward in the predictive accuracy of session-based recommendation systems.

CGG: Category-aware global graph contrastive learning for session-based recommendation

With the auxiliary role of category information in capturing user interests, employing category information to improve session-based recommendation (SBR) is getting an energetic research point. Recent studies organized the category-aware session as the graph structure and utilized the graph neural network to explore the session interest for SBR. However, existing studies only focused on the category information in the current session and failed to overcome inherent sparsity of session data, which resulted in suboptimal SBR performance. To overcome these deficiencies, we propose a Category-aware Global Graph contrastive learning method, namely CGG, for SBR. To be specific, we firstly construct the category-aware global graph based on global item-item transitions, item-category associations and global category-category transitions, which utilizes more sufficient category information across sessions to learn embeddings of categories and items. Furthermore, we design the hierarchical dual-pattern contrastive learning mechanism to model the information interaction of graphical and sequential patterns of a category-aware session, which overcomes the negative influence of sparse session data by injecting self-supervised signals. Extensive experiments on multiple real-world datasets verify that CGG outperforms seven mainstream SBR methods on different measurements.

Fusing temporal and semantic dependencies for session-based recommendation

Session-based recommendation (SBR) predicts the next item in user sequences. Existing research focuses on item transition patterns, neglecting semantic information dependencies crucial for understanding users’ preferences. Incorporating semantic characteristics is vital for accurate recommendations, especially in applications like user purchase sequences. In this paper, to tackle the above issue, we novelly propose a framework that hierarchically fuses temporal and semantic dependencies. Technically, we present the Item Transition Dependency Module and Semantic Dependency Module based on the whole session set: (i) Item Transition Dependency Module is exclusively to learn the item embeddings through temporal relations and utilizes item transitions from both global and local levels; (ii) Semantic Dependency Module develops mutually independent embeddings of both sessions and items via stable interaction relations. In addition, under the unified organization of the Cross View, semantic information is adaptively incorporated into the temporal dependency learning and used to improve the performance of SBR. Extensive experiments on three large-scale real-world datasets show the superiority of our framework over current state-of-the-art methods. In particular, our model improves its performance over SOTA on all three datasets, with 5.5%, 0.2%, and 3.0% improvements on Recall@20, and 5.8%, 4.6%, and 2.0% improvements on MRR@20, respectively.

Graph and Sequential Neural Networks in Session-based Recommendation: A Survey

Recent years have witnessed the remarkable success of recommendation systems (RSs) in alleviating the information overload problem. As a new paradigm of RSs, session-based recommendation (SR) specializes in users’ short-term preferences and aims to provide a more dynamic and timely recommendation based on ongoing interactions. This survey presents a comprehensive overview of the recent works on SR. First, we clarify the key definitions within SR and compare the characteristics of SR against other recommendation tasks. Then, we summarize the existing methods in two categories: sequential neural network based methods and graph neural network (GNN) based methods. The relevant frameworks and technical details are further introduced. Finally, we discuss the challenges of SR and new research directions in this area.

Learning multi-behavior user intent for session-based recommendation

Session-based recommendation makes a recommendation by exploiting short-term user interaction and has become a hot research topic. A quantity of methods have been proposed for session-based recommendation. Although effective, these methods focus on a particular behavior or fail to model the complex relationship between items with multiple behaviors. Thus they can only provide limited recommendation performance. To solve the above problem, we design a Multi-behavior User Intent Recommendation model (MUIR) to produce a recommendation to explore the complicated item–item dependencies with multiple behavior to make more effective recommendation. Technically, MUIR captures item–item cross-session global dependencies and generates behavior-specific user intent representations through a behavior-aware global attention encoder. MUIR employs a low-rank self-attention network to model in-session local dependencies within a session. Moreover, a proposed user behavior discrimination task is auxiliary optimized to disentangle the user intent with multiple behaviors. The extensive experiments show that our MUIR consistently outperforms the various state-of-the-art baselines.

Category-aware self-supervised graph neural network for session-based recommendation

Category-aware self-supervised graph neural network for session-based recommendation

Context enhanced multi-level attention model for session-based recommendation

Context enhanced multi-level attention model for session-based recommendation

SeSMR: Secure and Efficient Session-based Multimedia Recommendation in Edge Computing

Session-based multimedia recommendation in edge computing remains an important issue for boosting the utilization of services since service composition has increasingly attracted attention. Existing session-based recommendations (SBRs) model the session sequence with multilevel feature extraction in graph neural networks (GNNs). However, multilevel feature extraction in disentangled graph neural networks causes over-smoothing and privacy leakage. To address the aforementioned problems, Secure and Efficient Session-based Multimedia Recommendation (SeSMR) model is proposed. In the proposed SeSMR model, based on BGV homomorphic encryption, a ciphertext training submodel is proposed to address the privacy leakage, ensuring the security in session-based recommendation. Furthermore, based on the reinforcement of feature activation, a residual attention mechanism is proposed to mitigate over-smoothing while maintaining the independence of multiple features. Finally, based on location coding, a soft attention mechanism is proposed to improve the recommendation accuracy, by introducing the position difference information between items into intra-session and inter-session scenarios. Experiments demonstrate that both Recall and MRR metrics exhibit nearly 2%∼5% improvement.

Exploring multi-dimensional interests for session-based recommendation

Exploring multi-dimensional interests for session-based recommendation

MSD: Multi-Order Semantic Denoising Model for Session-Based Recommendations

Session-based recommendations which aim to predict subsequent user–item interactions based on historical user behaviour during anonymous sessions can be challenging to carry out. Two main challenges need to be addressed and improved: (1) how does one analyze these sessions to accurately and completely capture users’ preferences, and (2) how does one identify and eliminate any interference caused by noisy behavior? Existing methods have not adequately addressed these issues since they either neglect the valuable insights that can be gained from analyzing consecutive groups of items or fail to take these noisy data in sessions seriously and handle them properly, which can jointly impede recommendation systems from capturing users’ real intentions. To address these two problems, we designed a multi-order semantic denoising (MSD) model for session-based recommendations. Specifically, we grouped items of different lengths into varying multi-order semantic units to mine the user’s primary intentions from multiple dimensions. Meanwhile, a novel denoising network was designed to alleviate the interference of noisy behavior and provide a more precise session representation. The results of extensive experiments on three real-world datasets demonstrated that the proposed MSD model exhibited improved performance compared with existing state-of-the-art methods in session-based recommendations.

A Novel Popularity Extraction Method Applied in Session-Based Recommendation

A Novel Popularity Extraction Method Applied in Session-Based Recommendation

Session-based Recommendation Based on Long-term and Short-term Interest Incorporating Social Information

In session-based recommendation systems, user interests are dynamic and purchasing actions are often influenced by both long-term and short-term interest preferences. However, user interests are not solely influenced by the users themselves but also by other external factors, such as social connections. To address these issues, a method utilizing a Graph Attention Network is proposed, which effectively integrates both the long-term and short-term interests of users and their friends. Experiments on the Douban and Delicious datasets demonstrate that the proposed algorithm outperforms baseline models.

Skip-Gram and Transformer Model for Session-Based Recommendation

Session-based recommendation uses past clicks and interaction sequences from anonymous users to predict the next item most likely to be clicked. Predicting the user’s subsequent behavior in online transactions becomes a problem mainly due to the lack of user information and limited behavioral information. Existing methods, such as recurrent neural network (RNN)-based models that model user’s past behavior sequences and graph neural network (GNN)-based models that capture potential relationships between items, miss different time intervals in the past behavior sequence and can only capture certain types of user interest patterns due to the characteristics of neural networks. Graphic models created to improve the current session reduce the model’s success due to the addition of irrelevant items. Moreover, attention mechanisms in recent approaches have been insufficient due to weak representations of users and products. In this study, we propose a model based on the combination of skip-gram and transformer (SkipGT) to solve the above-mentioned drawbacks in session-based recommendation systems. In the proposed method, skip-gram both captures chained user interest in the session thread through item-specific subreddits and learns complex interaction information between items. The proposed method captures short-term and long-term preference representations to predict the next click with the help of a transformer. The transformer in our proposed model overcomes many limitations in turn-based models and models longer contextual connections between items more effectively. In our proposed model, by giving the transformer trained item embeddings from the skip-gram model as input, the transformer has better performance because it does not learn item representations from scratch. By conducting extensive experiments with three real-world datasets, we confirm that SkipGT significantly outperforms state-of-the-art solutions with an average MRR score of 5.58%.

Multi-Hop Multi-View Memory Transformer for Session-Based Recommendation

A Session-Based Recommendation (SBR) seeks to predict users’ future item preferences by analyzing their interactions with previously clicked items. In recent approaches, Graph Neural Networks (GNNs) have been commonly applied to capture item relations within a session to infer user intentions. However, these GNN-based methods typically struggle with feature ambiguity between the sequential session information and the item conversion within an item graph, which may impede the model’s ability to accurately infer user intentions. In this article, we propose a novel Multi-hop Multi-view Memory Transformer (M 3 T) to effectively integrate the sequence-view information and relation conversion (graph-view information) of items in a session. First, we propose a Multi-view Memory Transformer (M 2 T) module to concurrently obtain multi-view information of items. Then, a set of trainable memory matrices are employed to store sharable item features, which mitigates cross-view item feature ambiguity. To comprehensively capture latent user intentions, an M 3 T framework is designed to integrate user intentions across different hops of an item graph. Specifically, a k-order power method is proposed to manage the item graph to alleviate the over-smoothing problem when obtaining high-order relations of items. Extensive experiments conducted on three real-world datasets demonstrate the superiority of our method.

Gated graph spiking neural P network for session-based recommendation

Session-based recommendation (SBR) is a recommendation system application scenario that focuses on user interests and behaviors in sessions formed within a short period. However, existing SBR methods do not fully extract user contextual information, and gated graph neural networks(GNNs) still face challenges in handling long-term dependencies. The nonlinear spiking neural P system is a novel spiking neural-like computing model in which the nonlinear spiking mechanism is a typical feature. Based on this nonlinear spiking mechanism, we propose a new recurrent-like model called the extended gated spiking neural P model or the EGSNP model, which can effectively capture temporal relationships in their sequence and obtain the user’s contextual information to alleviate information extraction problems in SBR. Based on this EGSNP model, we propose a new type of GNN called the extended gated graph spiking neural P network or termed the EGGSNP network. Finally, we use the EGSNP model and EGGSNP network to construct a new SBR model for the session recommendation task, termed the SR-EGGSNP model. This SR-EGGSNP model can effectively extract contextual information and flexibly capture the long-term evolution of interest while alleviating the long-distance dependency problem in GNNs. We conducted extensive comparative experiments on two public datasets, and the results demonstrated the effectiveness of the proposed model and accuracy of the recommendations.

X-Model4Rec: An Extensible Recommender Model Based on the User’s Dynamic Taste Profile

Several approaches have been proposed to obtain successful models to solve complex next-item recommendation problem in non-prohibitive computational time, such as by using heuristics, designing architectures, and applying information filtering techniques. In the current technological scenario of artificial intelligence, sequential recommender systems have been gaining attention and they are a highly demanding research area, especially using deep learning in their development. Our research focuses on an efficient and practical model for managing sequential session-based recommendations of specific products for users using the wine and movie domains as case studies. Through an innovative recommender model called X-Model4Rec – eXtensible Model for Recommendation, we explore the user's dynamic taste profile using architectures with transformer and multi-head attention mechanisms to solve the next-item recommendation problem. The performance of the proposed model is compared to that of classical and baseline recommender models on two real-world datasets of wines and movies, and the results are better for most of the evaluation metrics.

Dual-Tower Counterfactual Session-Aware Recommender System.

In the complex dynamics of modern information systems such as e-commerce and streaming services, managing uncertainty and leveraging information theory are crucial in enhancing session-aware recommender systems (SARSs). This paper presents an innovative approach to SARSs that combines static long-term and dynamic short-term preferences within a counterfactual causal framework. Our method addresses the shortcomings of current prediction models that tend to capture spurious correlations, leading to biased recommendations. By incorporating a counterfactual viewpoint, we aim to elucidate the causal influences of static long-term preferences on next-item selections and enhance the overall robustness of predictive models. We introduce a dual-tower architecture with a novel data augmentation process and a self-supervised training strategy, tailored to tackle inherent biases and unreliable correlations. Extensive experiments demonstrate the effectiveness of our approach, outperforming existing benchmarks and paving the way for more accurate and reliable session-based recommendations.

Intention enhanced mixed attentive model for session-based recommendation

AbstractSession-based recommendation aims to generate recommendations for the next item of users’ interest based on a given session. In this manuscript, we develop intention enhanced mixed attentive model () to generate session-based recommendations using two important factors: temporal patterns and estimates of users’ intentions. Unlike existing methods which primarily leverage complicated gated recurrent units to model the temporal patterns, models the temporal patterns using a light-weight while effective position-sensitive attention mechanism. In , we also leverage the estimate of users’ prospective preferences to signify important items, and generate better recommendations. Our experimental results demonstrate that models significantly outperform the state-of-the-art methods in six benchmark datasets, with an improvement as much as 19.2%. In addition, our run-time performance comparison demonstrates that during testing, models are much more efficient than the best baseline method, with a significant average speedup of 47.7 folds.

Multi-perspective learning for enhanced user preferences for session-based recommendation

Due to the sparsity and anonymity of interactions within sessions, capturing user preferences by modeling item relationships poses a significant challenge. Previous methods have attempted to utilize collaborative information from adjacent sessions or item attribute knowledge as supplements. However, these methods are prone to introducing interfering information through their session similarity measurement strategies and attribute embedding learning processes, both requiring optimization. Moreover, they often fail to fully model global item relationships. To address these issues, we propose a novel method called Multi-perspective Learning for Enhanced User Preferences (MLEUP) for session-based recommendations. Specifically, we first construct reliable session groups by measuring the overlap and incompatibility of items across sessions to calculate session similarity. Then, by modeling attribute–item and attribute–attribute relationships, along with employing a neighbor-based contrastive self-supervised attribute learning task, we learn high-quality attribute embeddings that capture the user’s stable preferences. Next, leveraging the session groups, we model global item multi-granularity co-occurrence and high-order sequential relationships through designed attention layers, enabling us to learn informative item embeddings that represent the user’s dynamic preferences. Finally, we further model the correlated relationship between the two user preference representations. Our approach ensures that effective attribute knowledge and global collaborative information are learned to mitigate the data sparsity issue, while comprehensively modeling global item relationships to capture the user’s complex dynamic preferences. Experimental results demonstrate that MLEUP achieves state-of-the-art performance in terms of precision, MRR, and NDCG. The experimental datasets and source code of MLEUP are publicly available at https://github.com/lean030/MLEUP.

A Collaborative Filtering-Based Recommender Systems approach for Multifarious applications

Recommender systems are crucial in today's IT landscape, enhancing user experiences in various industries. Collaborative filtering (CF) is a key approach, using historical interaction data to predict user preferences. This paper presents CF advancements, with a focus on latent factor models that represent users and items in a compact feature space. It also addresses sparsity issues with techniques like neighborhood-based approaches and content augmentation. Contextual CF, which incorporates temporal and contextual dynamics, is explored through methods like matrix factorization with side information and session-based recommendation. Evaluation metrics such as MAE and RMSE, along with novel ranking-based metrics, provide a comprehensive assessment of recommendation quality. In this paper we outline cutting-edge CF techniques, showcasing their mechanisms and applications and were able to achieve accurate recommendations of almost 90% using MAE and RMSE metrics. By integrating latent factor modeling, sparsity mitigation, contextual enrichment, and advanced evaluation, it paves the way for the next generation of personalized recommendation systems, tailored to meet evolving demands in modern information environments.