Personal Assistant Systems
Bridging User Dynamics: Transforming Sequential Recommendations with Schr\"odinger Bridge and Diffusion Models
Xie, Wenjia, Zhou, Rui, Wang, Hao, Shen, Tingjia, Chen, Enhong
Sequential recommendation has attracted increasing attention due to its ability to accurately capture the dynamic changes in user interests. We have noticed that generative models, especially diffusion models, which have achieved significant results in fields like image and audio, hold considerable promise in the field of sequential recommendation. However, existing sequential recommendation methods based on diffusion models are constrained by a prior distribution limited to Gaussian distribution, hindering the possibility of introducing user-specific information for each recommendation and leading to information loss. To address these issues, we introduce the Schr\"odinger Bridge into diffusion-based sequential recommendation models, creating the SdifRec model. This allows us to replace the Gaussian prior of the diffusion model with the user's current state, directly modeling the process from a user's current state to the target recommendation. Additionally, to better utilize collaborative information in recommendations, we propose an extended version of SdifRec called con-SdifRec, which utilizes user clustering information as a guiding condition to further enhance the posterior distribution. Finally, extensive experiments on multiple public benchmark datasets have demonstrated the effectiveness of SdifRec and con-SdifRec through comparison with several state-of-the-art methods. Further in-depth analysis has validated their efficiency and robustness.
Towards Empathetic Conversational Recommender Systems
Zhang, Xiaoyu, Xie, Ruobing, Lyu, Yougang, Xin, Xin, Ren, Pengjie, Liang, Mingfei, Zhang, Bo, Kang, Zhanhui, de Rijke, Maarten, Ren, Zhaochun
Conversational recommender systems (CRSs) are able to elicit user preferences through multi-turn dialogues. They typically incorporate external knowledge and pre-trained language models to capture the dialogue context. Most CRS approaches, trained on benchmark datasets, assume that the standard items and responses in these benchmarks are optimal. However, they overlook that users may express negative emotions with the standard items and may not feel emotionally engaged by the standard responses. This issue leads to a tendency to replicate the logic of recommenders in the dataset instead of aligning with user needs. To remedy this misalignment, we introduce empathy within a CRS. With empathy we refer to a system's ability to capture and express emotions. We propose an empathetic conversational recommender (ECR) framework. ECR contains two main modules: emotion-aware item recommendation and emotion-aligned response generation. Specifically, we employ user emotions to refine user preference modeling for accurate recommendations. To generate human-like emotional responses, ECR applies retrieval-augmented prompts to fine-tune a pre-trained language model aligning with emotions and mitigating hallucination. To address the challenge of insufficient supervision labels, we enlarge our empathetic data using emotion labels annotated by large language models and emotional reviews collected from external resources. We propose novel evaluation metrics to capture user satisfaction in real-world CRS scenarios. Our experiments on the ReDial dataset validate the efficacy of our framework in enhancing recommendation accuracy and improving user satisfaction.
Exploring User Acceptance Of Portable Intelligent Personal Assistants: A Hybrid Approach Using PLS-SEM And fsQCA
Mvondo, Gustave Florentin Nkoulou, Niu, Ben
This research explores the factors driving user acceptance of Rabbit R1, a newly developed portable intelligent personal assistant (PIPA) that aims to redefine user interaction and control. The study extends the technology acceptance model (TAM) by incorporating artificial intelligence-specific factors (conversational intelligence, task intelligence, and perceived naturalness), user interface design factors (simplicity in information design and visual aesthetics), and user acceptance and loyalty. Using a purposive sampling method, we gathered data from 824 users in the US and analyzed the sample through partial least squares structural equation modeling (PLS-SEM) and fuzzy set qualitative comparative analysis (fsQCA). The findings reveal that all hypothesized relationships, including both direct and indirect effects, are supported. Additionally, fsQCA supports the PLS-SEM findings and identifies three configurations leading to high and low user acceptance. This research enriches the literature and provides valuable insights for system designers and marketers of PIPAs, guiding strategic decisions to foster widespread adoption and long-term engagement.
Transformers Meet ACT-R: Repeat-Aware and Sequential Listening Session Recommendation
Tran, Viet-Anh, Salha-Galvan, Guillaume, Sguerra, Bruno, Hennequin, Romain
Music streaming services often leverage sequential recommender systems to predict the best music to showcase to users based on past sequences of listening sessions. Nonetheless, most sequential recommendation methods ignore or insufficiently account for repetitive behaviors. This is a crucial limitation for music recommendation, as repeatedly listening to the same song over time is a common phenomenon that can even change the way users perceive this song. In this paper, we introduce PISA (Psychology-Informed Session embedding using ACT-R), a session-level sequential recommender system that overcomes this limitation. PISA employs a Transformer architecture learning embedding representations of listening sessions and users using attention mechanisms inspired by Anderson's ACT-R (Adaptive Control of Thought-Rational), a cognitive architecture modeling human information access and memory dynamics. This approach enables us to capture dynamic and repetitive patterns from user behaviors, allowing us to effectively predict the songs they will listen to in subsequent sessions, whether they are repeated or new ones. We demonstrate the empirical relevance of PISA using both publicly available listening data from Last.fm and proprietary data from Deezer, a global music streaming service, confirming the critical importance of repetition modeling for sequential listening session recommendation. Along with this paper, we publicly release our proprietary dataset to foster future research in this field, as well as the source code of PISA to facilitate its future use.
Do Recommender Systems Promote Local Music? A Reproducibility Study Using Music Streaming Data
Matrosova, Kristina, Marey, Lilian, Salha-Galvan, Guillaume, Louail, Thomas, Bodini, Olivier, Moussallam, Manuel
This paper examines the influence of recommender systems on local music representation, discussing prior findings from an empirical study on the LFM-2b public dataset. This prior study argued that different recommender systems exhibit algorithmic biases shifting music consumption either towards or against local content. However, LFM-2b users do not reflect the diverse audience of music streaming services. To assess the robustness of this study's conclusions, we conduct a comparative analysis using proprietary listening data from a global music streaming service, which we publicly release alongside this paper. We observe significant differences in local music consumption patterns between our dataset and LFM-2b, suggesting that caution should be exercised when drawing conclusions on local music based solely on LFM-2b. Moreover, we show that the algorithmic biases exhibited in the original work vary in our dataset, and that several unexplored model parameters can significantly influence these biases and affect the study's conclusion on both datasets. Finally, we discuss the complexity of accurately labeling local music, emphasizing the risk of misleading conclusions due to unreliable, biased, or incomplete labels. To encourage further research and ensure reproducibility, we have publicly shared our dataset and code.
Towards Graph Prompt Learning: A Survey and Beyond
Long, Qingqing, Yan, Yuchen, Zhang, Peiyan, Fang, Chen, Cui, Wentao, Ning, Zhiyuan, Xiao, Meng, Cao, Ning, Luo, Xiao, Xu, Lingjun, Jiang, Shiyue, Fang, Zheng, Chen, Chong, Hua, Xian-Sheng, Zhou, Yuanchun
Large-scale "pre-train and prompt learning" paradigms have demonstrated remarkable adaptability, enabling broad applications across diverse domains such as question answering, image recognition, and multimodal retrieval. This approach fully leverages the potential of large-scale pre-trained models, reducing downstream data requirements and computational costs while enhancing model applicability across various tasks. Graphs, as versatile data structures that capture relationships between entities, play pivotal roles in fields such as social network analysis, recommender systems, and biological graphs. Despite the success of pre-train and prompt learning paradigms in Natural Language Processing (NLP) and Computer Vision (CV), their application in graph domains remains nascent. In graph-structured data, not only do the node and edge features often have disparate distributions, but the topological structures also differ significantly. This diversity in graph data can lead to incompatible patterns or gaps between pre-training and fine-tuning on downstream graphs. We aim to bridge this gap by summarizing methods for alleviating these disparities. This includes exploring prompt design methodologies, comparing related techniques, assessing application scenarios and datasets, and identifying unresolved problems and challenges. This survey categorizes over 100 relevant works in this field, summarizing general design principles and the latest applications, including text-attributed graphs, molecules, proteins, and recommendation systems. Through this extensive review, we provide a foundational understanding of graph prompt learning, aiming to impact not only the graph mining community but also the broader Artificial General Intelligence (AGI) community.
Contextual Bandit with Herding Effects: Algorithms and Recommendation Applications
Xu, Luyue, Wang, Liming, Xie, Hong, Zhou, Mingqiang
Contextual bandits serve as a fundamental algorithmic framework for optimizing recommendation decisions online. Though extensive attention has been paid to tailoring contextual bandits for recommendation applications, the "herding effects" in user feedback have been ignored. These herding effects bias user feedback toward historical ratings, breaking down the assumption of unbiased feedback inherent in contextual bandits. This paper develops a novel variant of the contextual bandit that is tailored to address the feedback bias caused by the herding effects. A user feedback model is formulated to capture this feedback bias. We design the TS-Conf (Thompson Sampling under Conformity) algorithm, which employs posterior sampling to balance the exploration and exploitation tradeoff. We prove an upper bound for the regret of the algorithm, revealing the impact of herding effects on learning speed. Extensive experiments on datasets demonstrate that TS-Conf outperforms four benchmark algorithms. Analysis reveals that TS-Conf effectively mitigates the negative impact of herding effects, resulting in faster learning and improved recommendation accuracy.
Modeling and Analyzing the Influence of Non-Item Pages on Sequential Next-Item Prediction
Fischer, Elisabeth, Schlör, Daniel, Zehe, Albin, Hotho, Andreas
Analyzing the sequence of historical interactions between users and items, sequential recommendation models learn user intent and make predictions about the next item of interest. Next to these item interactions, most systems also have interactions with pages not related to specific items, for example navigation pages, account pages, and pages for a specific category, which may provide additional insights into the user's interests. However, while there are several approaches to integrate additional information about items and users, the topic of integrating non-item pages has been less explored. We use the hypotheses testing framework HypTrails to show that there is indeed a relationship between these non-item pages and the items of interest and fill this gap by proposing various approaches of representing non-item pages (e.g, based on their content) to use them as an additional information source for the task of sequential next-item prediction. We create a synthetic dataset with non-item pages highly related to the subsequent item to show that the models are generally capable of learning from these interactions, and subsequently evaluate the improvements gained by including non-item pages in two real-world datasets. We adapt eight popular sequential recommender models, covering CNN-, RNN- and transformer-based architectures, to integrate non-item pages and investigate the capabilities of these models to leverage their information for next item prediction. We also analyze their behavior on noisy data and compare different item representation strategies. Our results show that non-item pages are a valuable source of information, but representing such a page well is the key to successfully leverage them. The inclusion of non-item pages can increase the performance for next-item prediction in all examined model architectures with a varying degree.
Gay Brazilians targeted in deadly stickups, lured by dating apps
It was June 12, Lover's Day in Brazil. Leo Nunes, 24, had spent a few days talking to someone he met on Hornet, a popular gay dating app, before arranging their first encounter in Sao Paulo's middle-class Sacoma neighborhood. A security camera captured the moment that two men on a motorcycle showed up in the alley where he was waiting, grabbed his phone and shot him dead. The Nunes family, who shared details of the investigation with Reuters, said one suspect had been arrested. Sao Paulo police said they are investigating the shooting as a robbery resulting in a homicide, but did not provide further information or confirm if there had been an arrest.
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