Multimodal aspect-based sentiment analysis (MABSA) is an essential task in the field of sentiment analysis, which still confronts several critical challenges. The first challenge is how to effectively capture key information within both image and text features to enhance the recognition and understanding of complex sentiment expressions. The second challenge is how to achieve cross-modal alignment of multi-granularity text features and image features. The third challenge is how to narrow the semantic gap between image modality and text modality through effective cross-modal feature fusion. To address these issues, a framework that leverages external knowledge and multi-granularity image and text features (EKMG) is proposed. Firstly, an external knowledge enhanced semantic extraction module is introduced to fuse external knowledge with image features and text features, thereby capturing the key information from texts and images. Secondly, we design a multi-granularity image-text contrastive learning module. This module initially introduces a graph attention network and a novel cross-modal fusion mechanism to align image features and text features at multiple granularities. Additionally, the module employs an image-text contrastive learning strategy to narrow the semantic gap between different modalities. Experimental results on two public benchmark datasets demonstrate that EKMG achieves significant performance improvements compared to state-of-the-art baseline models.

Multimodal sarcasm detection has received considerable attention due to its unique role in social networks. Existing methods often rely on feature concatenation to fuse different modalities or model the inconsistencies among modalities. However, sarcasm is often embodied in local and momentary nuances in a subtle way, which causes difficulty for sarcasm detection. To effectively incorporate these nuances, this paper presents Context-Aware Self-Attention Fusion (CAAF) to integrate local and momentary multimodal information into specific words. Furthermore, due to the instantaneous nature of sarcasm, the connotative meanings of words post-multimodal integration generally deviate from their denotative meanings. Therefore, Word Weight Calculation (WWC) is presented to compute the weight of specific words based on CAAF’s fusion nuances, illustrating the inconsistency between connotation and denotation. We evaluate our method on the MUStARD dataset, achieving an accuracy of 76.9 and an F1 score of 76.1, which surpasses the current state-of-the-art IWAN model by 1.7 and 1.6 respectively.

The widespread availability of smart mobile terminals along with the ever increasing bandwidth capabilities has promoted the popularity of mobile Internet video systems. Understanding the geographic features of mobile content consumption is of an extreme importance for the design and the performance optimization of a mobile video delivery system. This paper is a first step towards characterization of the geographic patterns of a large-scale commercial mobile video-on-demand (VoD) system, by measuring both uniformity and intensity of geographic interests on videos. In particular, we identify a geographical concentration effect of views for individual videos, which is however dependent on video popularity. We also analyze the temporal evolution trends of the geographic popularity which reveal distinct behavior of popular and non-popular videos. While the set of locations that contribute to most of the views of non-popular videos largely varies, the daily geographic popularity distribution of popular videos closely follows the distribution of global traffic and remains stable. We also examine the impact of content type and viewing sources on the geographic features of mobile videos consumption, and the correlation between content similarity and geographic locality. Finally, we provide insights into the implications of our findings.

User-generated content (UGC) video systems by definition heavily depend on the input of their community of users and their social interactions for video diffusion and opinion sharing. Nevertheless, we show in this paper, through measurement and analysis of YouKu, the most popular UGC video system in China, that the social connectivity of its users is very low. These observations are consistent with what was reported about YouTube in previous works. As a UGC system can achieve a larger audience through improved connectivity, our findings motivate us to propose a mean to enhance the users' connectivity by taking benefit of friend recommendation. To this end, we assess two similarity metrics based on users' interests that are derived from their uploads and favorites tagging of videos, to evaluate the interest similarity between friends. The results consistently show that friends share to a great extent common interests. Two friend recommendation algorithms are then proposed. The algorithms use public information provided by users to suggest potential friends with similar interests as measured by the similarity metrics. Experiments on our gathered YouKu dataset demonstrate that the social connectivity can be greatly enhanced by our friend proposition set and that users can access a larger set of interesting videos through the recommendations.

The subscription in UGC (user-generated content) video systems provides shortcuts for users to be aware of emerging videos from their subscribings. While the subscription is deemed to have great impacts on video views, its patterns and impacts on the user popularity are not well understood. By measuring YouKu, the largest UGC video system in China, we have found stretched exponential distributions for subscribers, subscribings, rather than power-law distributions. We further examine to whom users would like to subscribe and the correlation between the friendship and subscription. Finally, we analyze the impacts of subscription on user popularity. Our findings can be leveraged for the design of subscription/video recommendation systems and the prediction schemes in UGC video systems.

In this work, we aim to analyze and compare interaction patterns in different types of social platforms. To this end, we measured Renren, the largest online social network in China, and Sina Weibo, the most popular microblog service in China. We model the interaction networks as unidirectional weighted graphs in light of the asymmetry of user interactions. Following this model, we first study the basic interaction patterns. Then, we examine whether weak ties hypothesis holds in these interaction graphs and analyze the impacts on information diffusion. Furthermore, we model the temporal patterns of user interactions and cluster users based on the temporal patterns. Our findings demonstrate that although users in the two platforms share some common interaction patterns, users in Sina Weibo are more popular and diverse. Moreover, analysis and simulation results show that Sina Weibo is a more efficient platform for information diffusion. These findings provide an in-depth understanding of interaction patterns in different social platforms and can be used for the design of efficient information diffusion.

In this paper, we examine mobile users' behavior and their corresponding video viewing patterns from logs extracted from the servers of a large scale VoD system. We focus on the analysis of the main discrepancies that might exist when users access the VoD system catalog from WiFi or 3G connections. We also study factors that might impact mobile users' interests and video popularity. The users' behavior exhibits strong daily and weekly patterns, with mobile users' interests being surprisingly spread across almost all categories and video lengths, independently of the connection type. However, by examining the activity of users individually, we observed a concentration of interests and peculiar access patterns, which allows to classify the users and thus better predict their behavior. We also find a skewed video popularity distribution and then demonstrate that the popularity of a video can be predicted using its very early popularity level. We further analyzed the sources of video viewing and found that even if search engines are the dominant sources for a majority of videos, they represent less than 10% (resp. 20%) of the sources for the highly popular videos in 3G (resp. WiFi) network. We report that both the type of connections and mobile devices in use have an impact on the viewing time and the source of viewing. Based on our findings, we provide insights and recommendations that can be used to design intelligent mobile VoD systems and help improving personalized services on these platforms.