Social platforms such as Twitter are increasingly threatened by automated social bots, which can manipulate public opinion, spread misinformation, and compromise platform integrity. To detect such accounts, various methods have been proposed, with many recent approaches leveraging graph neural networks (GNNs) due to their ability to model relational structures among users. However, these models may be vulnerable to adversarial perturbations that exploit their structural dependencies. To investigate this vulnerability, we propose a targeted black-box node injection attack that deceives detection models by injecting a new bot near a target bot, causing both to evade detection. This attack is specifically designed to exploit GNN-based model behaviors and does not require any access to model parameters or architecture. Given the success of this attack in exposing structural weaknesses, it is essential to develop effective defenses to improve the robustness of detection models. To this end, we introduce a cost-efficient adversarial training method with reweighted supervision, which selectively emphasizes adversarial samples during learning. This approach improves model robustness without increasing computational cost or requiring additional data. The effectiveness of our attack and defense methods is demonstrated through experiential evaluations conducted on six different models. Specifically, we achieve a maximum attack success rate (ASR) of 95.74% and robustness improvement of 95.74% in Cresci-2015 and achieve a maximum ASR of 97.15% and robustness improvement of 56.20% in TwiBot-22. The detection performance of the models fluctuates less than 2% after adversarial training.

News captioning aims to describe an image with its news article body as input. It greatly relies on a set of detected named entities, including real-world people, organizations, and places. This article exploits commonsense knowledge to understand named entities for news captioning. By “understand,” we mean correlating the news content with commonsense in the wild, which helps an agent to (1) distinguish semantically similar named entities and (2) describe named entities using words outside of training corpora. Our approach consists of three modules: (a) Filter Module aims to clarify the commonsense concerning a named entity from two aspects: what does it mean ? and what is it related to ?, which divide the commonsense into explanatory knowledge and relevant knowledge , respectively. (b) Distinguish Module aggregates explanatory knowledge from node-degree , dependency , and distinguish three aspects to distinguish semantically similar named entities. (c) Enrich Module attaches relevant knowledge to named entities to enrich the entity description by commonsense information (e.g., identity and social position). Finally, all of information is integrated into the large multimodal model to generate the news caption. Extensive experiments on two challenging datasets (i.e., GoodNews and NYTimes) demonstrate the superiority of our method. Ablation studies and visualization further validate its effectiveness in understanding named entities.

Iterative language-based image manipulation aims to edit images step by step according to user's linguistic instructions. The existing methods mostly focus on aligning the attributes and appearance of new-added visual elements with current instruction. However, they fail to maintain consistency between instructions and images as iterative rounds increase. To address this issue, we propose a novel Long and Short term consistency reasoning Generative Adversarial Network (LS-GAN), which enhances the awareness of previous objects with current instruction and better maintains the consistency with the user's intent under the continuous iterations. Specifically, we first design a Context-aware Phrase Encoder (CPE) to learn the user's intention by extracting different phrase-level information about the instruction. Further, we introduce a Long and Short term Consistency Reasoning (LSCR) mechanism. The long-term reasoning improves the model on semantic understanding and positional reasoning, while short-term reasoning ensures the ability to construct visual scenes based on linguistic instructions. Extensive results show that LS-GAN improves the generation quality in terms of both object identity and position, and achieves the state-of-the-art performance on two public datasets.

Under the heavy management on the increasing 3D models, the topic of image-based 3D model retrieval which organizes unlabeled 3D models based on abundant knowledge learned from labeled 2D images has drawn attention. However, prior methods are limited in aligning semantically at corresponding categories of two domains due to the lack of label information in the 3D domain. To this end, this paper proposes an improved semantic representation learning by multiple clustering approach, which improves the reliability of pseudo labels for 3D models, so as to achieve class-level semantic alignment. Specifically, this paper first extracts features for 2D images and 3D models. Then it clusters combining the 3D features with the semantic information from multiple clustering on 3D model features to obtain more reliable target pseudo labels. Extensive experiments have shown that the proposed method has achieved the gain of 3.0%-205.0% averagely for popular retrieval metrics on the benchmark of monocular image-based 3D object retrieval (MI3DOR), and 1.3%-69.7% on another advanced benchmark, MI3DOR-2.

With the popularization of social media, the way of information transmission has changed, and the prediction of information popularity based on social media platforms has attracted extensive attention. Feature fusion-based media popularity prediction methods focus on the multi-modal features of social media, which aim at exploring the key factors affecting media popularity. Meanwhile, the methods make up for the deficiency in feature utilization of traditional methods based on information propagation processes. In this paper, we review feature fusion-based media popularity prediction methods from the perspective of feature extraction and predictive model construction. Before that, we analyze the influencing factors of media popularity to provide intuitive understanding. We further argue about the advantages and disadvantages of existing methods and datasets to highlight the future directions. Finally, we discuss the applications of popularity prediction. To the best of our knowledge, this is the first survey reporting feature fusion-based media popularity prediction methods.

Image Captioning is a cross-modal task that needs to automatically generate coherent natural sentences to describe the image contents. Due to the large gap between vision and language modalities, most of the existing methods have the problem of inaccurate semantic matching between images and generated captions. To solve the problem, this paper proposes a novel multi-level similarity-guided semantic matching method for image captioning, which can fuse local and global semantic similarities to learn the latent semantic correlation between images and generated captions. Specifically, we extract the semantic units containing fine-grained semantic information of images and generated captions, respectively. Based on the comparison of the semantic units, we design a local semantic similarity evaluation mechanism. Meanwhile, we employ the CIDEr score to characterize the global semantic similarity. The local and global two-level similarities are finally fused using the reinforcement learning theory, to guide the model optimization to obtain better semantic matching. The quantitative and qualitative experiments on large-scale MSCOCO dataset illustrate the superiority of the proposed method, which can achieve fine-grained semantic matching of images and generated captions.