Social networks exhibit a distinct "celebrity effect" whereby influential individuals have a more significant impact on others compared to ordinary individuals, unlike other network structures such as citation networks and knowledge graphs. Despite its common occurrence in social networks, the celebrity effect is frequently overlooked by existing social recommendation methods when modeling social relationships, thereby hindering the full exploitation of social networks to mine similarities between users. In this paper, we fill this gap and propose a Celebrity-aware Graph Contrastive Learning Framework for Social Recommendation (CGCL), which explicitly models the celebrity effect in the social domain. Technically, we measure the different influences of celebrity and ordinary nodes by mining social network structure features, such as closeness centrality. To model the celebrity effect in social networks, we design a novel user-user impact-aware aggregation method, which incorporates the celebrity-aware influence information into the message propagation process. Additionally, we design a graph neural network-based framework which incorporates social semantics into the user-item interaction modeling with contrastive learning-enhanced data augmentation. The experimental results on three real-world datasets show the effectiveness of the proposed framework. We conduct ablation experiments to prove that the key components of our model benefit the recommendation performance improvement.

Quality of life (QoL) is an effective index of well-being, including physical health, aspect of social activity, and mental state of individuals. A new approach that uses a deep-learning architecture to estimate the score of a user's QoL is presented. This system was built using a combination of a 3D convolutional neural network and a support vector machine for multimodal data. In order to evaluate the accuracy of the estimation system, three experiments were conducted. Before these experiments, ten hours of audio and video data were collected from healthy participants during a natural-language conversation with a conversational agent we implemented. In the first experiment, the QoL question-answer estimation experiment, the accuracy of “Physical functioning,” which is one of the eight scales that constitute QoL, reached 84.0%. In the second experiment, the QoL-score-regression experiment, in which the scores of each scale were directly estimated, the distribution of the difference between the actual score and the estimated results, known as error, was investigated. These results imply that the features necessary for QoL estimation can be extracted from audio and video data, except for the “Mental Health” domain. One of the reasons why it was difficult to estimate the “Mental Health” scale may be that the learning framework could not extract an appropriate feature for estimation. Therefore, we estimated “Mental Health” by focusing on eye movement. From the result, it was proven that estimation is possible, and the proposed system using multimodal data demonstrated its effectiveness for estimation for all eight scales that constitute QoL and for extracting high-dimensional information regarding the QoL of a human, including their satisfaction level towards daily life and social activities. Finally, suggestions and discussions regarding the plausible behavior of the estimation results were made from the viewpoint of human–agent interaction in the field of elderly welfare.

Agents that build interactive relationships with people can provide appropriate support and generate behaviors by accurately grasping the state of the person. This study focuses on the quality of life (QOL), which can be assessed multidimensionally, and aims to estimate QOL scores in the process of human interaction. Although vision-based estimation has been the main method for QOL estimation, we proposed a new text-based estimation method. We created a QOL-specific dictionary called SqolDic, which is based on large-scale Japanese textual data. To evaluate the effectiveness of SqolDic, we implemented a system that outputs the time-series variation of a user’s conversation content and the QOL scores based on it. In an experiment for estimating the content of user conversations based on a QOL scale by inputting data from actual human conversations, we achieved a maximum estimation accuracy of 91.2%. Additionally, in an experiment to estimate QOL score variability, we successfully estimated the mental health state and one of the QOL scales with a smaller distribution of error than that in previous studies. The experimental results demonstrated the effectiveness of our system in estimating conversation content and QOL scores as well as the effectiveness of our newly proposed QOL dictionary.