United States

Rumor detection is critical as the spread of misinformation on social media threatens social stability. The propagation structure has gained attention for its ability to capture discriminative information, such as crowd stance, leading to improved detection methods using propagation trees. However, these detectors are vulnerable to attacks that can manipulate results and evade detection, potentially disrupting public order or influencing public opinion. While adversarial attacks on rumor detectors have been studied, the use of backdoor attacks—an evasive and powerful method—remains unexplored due to the challenges in applying them to propagation trees. In this paper, we introduce the first backdoor attack framework against propagation-based rumor detectors, designed to maintain overall detector performance while enabling targeted attacks on specific rumors. We propose an adaptive discrete trigger generator that injects trigger nodes into critical nodes, creating evasive, transferable attacks. Extensive experiments on three real-world rumor datasets demonstrate that our framework effectively undermines the performance of propagation-based rumor detectors and is transferable across different architectures.

AAAI 2025

Backdoor Attack on Propagation-based Rumor Detectors

graph based machine learning

## Welcome!
"I am excited to welcome you to this year’s edition of the Conference on Empirical Methods in Natural Language Processing! Importantly, it marks the 30th edition of EMNLP. With over 8,000 submissions, more than 3,000 accepted papers, and thousands of attendees, we have come a long way from that first
workshop, which had 14 accepted papers. As the field looks ahead, Suzhou is the fitting location for celebrating this milestone: rooted in a long literary tradition, yet modern and forward-looking, and home to a large share of the NLP community." 

*Message from the General Chair, Dirk Hovy*

EMNLP 2025

Celebrate 30 Years of EMNLP! 
EMNLP 2025 will be held in Suzhou, China from November 5th to November 9th, 2025.

technical paper

We are pleased to announce the Thirty-Ninth AAAI Conference on Artificial Intelligence (AAAI-25), which will be held in Philadelphia, Pennsylvania at the Pennsylvania Convention Center from February 25 to March 4, 2025.

The purpose of the AAAI conference series is to promote research in Artificial Intelligence (AI) and foster scientific exchange between researchers, practitioners, scientists, students, and engineers across the entirety of AI and its affiliated disciplines. AAAI-25 will feature technical paper presentations, special tracks, invited speakers, workshops, tutorials, poster sessions, senior member presentations, competitions, and exhibit programs, and a range of other activities to be announced.

### [Invited Speakers](https://aaai.org/conference/aaai/aaai-25/aaai-25-invited-speakers/)

Register [here](https://aaai.org/conference/aaai/aaai-25/registration/)

The purpose of the AAAI conference series is to promote research in Artificial Intelligence (AI) and foster scientific exchange between researchers, practitioners, scientists, students, and engineers across the entirety of AI and its affiliated disciplines. AAAI-25 will feature technical paper presentations, special tracks, invited speakers, workshops, tutorials, poster sessions, senior member presentations, competitions, and exhibit programs, and a range of other activities to be announced.



The task of one-shot face video re-enactment aims at generating target video of faces with the same identity of one source frame and facial deformation of the driving video. To achieve high quality generation, it is essential to precisely disentangle identity-related and  identity-independent characteristics, meanwhile build expressive features keeping high-frequency facial details, which still remain unaddressed for existing approaches. To deal with these two challenges, we propose a two-stage generation model based on StyleGAN, whose key novel techniques lie in better disentangling identity and deformation codes in the latent space through an identity-based modeling and manipulating intermediate StyleGAN features at the second stage for augmenting facial details of the generating targets. To further improve identity consistency, a data augmentation method is introduced during training for enhancing the key features affecting identity such as hair and wrinkles. Extensive experimental results demonstrate the superiority of our approach compared state-of-the-art approaches. Code is available at https://anonymous.4open.science/r/ViVFace-CBD3.

Enhancing Identity-Deformation Disentanglement in StyleGAN for One-Shot Face Video Re-Enactment

High Dynamic Range (HDR) video reconstruction is a technology designed to restore the real-world dynamic range as accurately as possible, and it is widely used in photography, video games, and virtual reality. Existing methods typically process one or a few adjacent frames together, which can lead to inconsistencies in brightness across frames because they do not treat the video as a whole. Additionally, the methods under supervised learning hold data bias from collected training data and degrade their effectiveness when the unseen test cases have a domain gap with the training ones. To address these issues, we propose an event-guided HDR video reconstruction method based on 3D Gaussian Splatting.  We use 3D Gaussians to represent the entire video, ensuring consistent brightness in the HDR output.  Since existing 3D Gaussians are limited to representing the 0-255 range, we have designed an HDR 3D Gaussian that can represent both HDR and LDR simultaneously.  Additionally, we employ learnable parameters to model the relationship between events and LDR images.  Our method is self-supervised, eliminating data bias present in existing event-guided HDR video reconstruction approaches. The proposed method demonstrates state-of-the-art performance both quantitatively and qualitatively for synthetic and real-world data.

EvHDR-GS: Event-guided HDR Video Reconstruction with 3D Gaussian Splatting

Domain adaptive object detection (DAOD) aims to generalize an object detector trained on labeled source-domain data to a target domain without annotations, the core principle of which is source-target feature alignment. Typically, existing approaches employ adversarial learning to align the distributions of the source and target domains as a whole, barely considering the varying significance of distinct regions, say instances under different circumstances and foreground vs background areas, during feature alignment. To overcome the shortcoming, this work investigates a differential feature alignment strategy. Specifically, a prediction-discrepancy feedback instance alignment module (dubbed PDFA) is designed to adaptively assign higher weights to instances of higher teacher-student detection discrepancy, effectively handling heavier domain-specific information. On the other hand, an uncertainty-based foreground-oriented image alignment module (UFOA) is proposed to explicitly guide the model to focus more on regions of interest. Extensive experiments on widely-used DAOD datasets together with ablation studies are conducted to demonstrate the efficacy of our proposed method and reveal its superiority over other SOTA alternatives. Our code will be made publicly available.

Differential Alignment for Domain Adaptive Object Detection

Deep hashing models have achieved great success in retrieval tasks due to their powerful representation ability and strong information compression capabilities. However, they inherit the vulnerability of deep neural networks to adversarial perturbations. Attackers can severely impact the retrieval capability of hashing models by adding small, carefully crafted adversarial perturbations to benign images, transforming them into adversarial images. Most existing adversarial attacks target image classification models, with few focusing on hashing retrieval models. We propose HUANG, a targeted adversarial attack algorithm for hashing retrieval in black-box scenarios. To the best of our knowledge, this is the first algorithm that leverages a diffusion model to achieve adversarial attacks on retrieval models. In our approach, adversarial denoising uses adversarial perturbations and residual images to guide the shift from benign to adversarial distribution. Extensive experiments demonstrate the superiority of HUANG across different datasets, achieving state-of-the-art performance in black-box targeted attacks. Additionally, the dynamic interplay between denoising and adding adversarial perturbations in adversarial denoising endows HUANG with exceptional robustness and transferability.

HUANG: A Robust Diffusion Model-based Targeted Adversarial Attack Against Deep Hashing Retrieval

Probability calibration transforms raw output of a classification model into empirically interpretable probability. When the model is purposed to detect rare event and only a small expensive data source has clean labels, it becomes extraordinarily challenging to obtain accurate probability calibration. Utilizing an additional large cheap data source is very helpful, however, such data sources oftentimes suffer from biased labels. To this end, we introduce an approximate expectation-maximization (EM) algorithm to extract useful information from the large data sources. For a family of calibration methods based on the logistic likelihood, we derive closed-form updates and call the resulting iterative algorithm CalEM. We shpw that CalEM inherits convergence guarantees from the approximate EM algorithm. We test the proposed model in simulation and on the marketing uplift dataset, where it shows significant performance increases.

Improving Model Probability Calibration by Integration of Large Data Sources with Biased Labels

A recent endeavor in one class of video anomaly detection is to leverage diffusion models and posit the task as a generation problem, where the diffusion model is trained to recover normal patterns exclusively, thus reporting abnormal patterns as outliers. Yet, existing attempts neglect the various formations of anomaly and predict normal samples at the feature level regardless that abnormal objects in surveillance videos are often relatively small.
To address this, a novel patch-based diffusion model is proposed, specifically engineered to capture fine-grained local information. We further observe that anomalies in videos manifest themselves as deviations in both appearance and motion. Therefore, we argue that a comprehensive solution must consider both of these aspects simultaneously to achieve accurate frame prediction. To address this, we introduce innovative motion and appearance conditions that are seamlessly integrated into our patch diffusion model. These conditions are designed to guide the model in generating coherent and contextually appropriate predictions for both semantic content and motion relations. Experimental results on four challenging video anomaly detection datasets empirically substantiate the efficacy of our proposed approach, demonstrating that it consistently outperforms most existing methods in detecting abnormal behaviors.

Video Anomaly Detection with Motion and Appearance Guided Patch Diffusion Model

Noisy labels can negatively impact deep neural network performance. One common solution is label refurbishment, which involves reconstructing noisy labels through predictions and distributions. However, these methods may introduce problematic semantic associations, a phenomenon we identify as Semantic Contamination. Through an analysis of Robust LR, a representative label refurbishment method, we found that utilizing the logits of views for refurbishment does not adequately balance the semantic information of individual classes. Conversely, using the logits of models fails to maintain consistent semantic relationships across models, which explains why label refurbishment methods frequently encounter issues related to Semantic Contamination. To address this issue, we propose a novel method called Collaborative Cross Learning, which utilizes semi-supervised learning on refurbished labels to extract appropriate semantic associations from embeddings across views and models. Experimental results show that our method outperforms existing approaches on both synthetic and real-world noisy datasets, effectively mitigating the impact of label noise and Semantic Contamination.

Combating Semantic Contamination in Learning with Label Noise

The strength of multimodal learning lies in its ability to integrate information from various sources, providing rich and comprehensive insights. However, in real-world scenarios, multi-modal systems often face the challenge of dynamic modality contributions, the dominance of different modalities may change with the environments, leading to suboptimal performance in multimodal learning. Current methods mainly enhance weak modalities to balance multimodal representation bias, which inevitably optimizes from a partial modality perspective, easily leading to performance descending for dominant modalities. To address this problem, we propose an Asymmetric Reinforcing method against Multimodal Representation bias (ARMR). Our ARMR dynamically reinforces on the weak modalities while maintaining the representation ability of dominant modalities through condition mutual information. Moreover, we first provide an in-depth analysis that optimizing certain modalities could cause information loss and prevent leveraging the full advantages of multimodal data. By exploring the dominance and narrowing the contribution gaps between modalities, we have significantly improved the performance of multimodal learning, making notable progress in mitigating imbalanced multimodal cooperation.

Asymmetric Reinforcing against Multi-modal Representation Bias

With the explosive growth of deep learning applications, the right to be forgotten has been required unprecedentedly in various AI industries. For example, given a facial recognition system, some individuals may wish to remove images that might have been used in the training phase from the trained model. Unfortunately, modern deep neural networks sometimes unexpectedly leak personal identities.
Recent studies have presented various machine unlearning algorithms to make a trained model unlearn the data to be forgotten. 
While these methods generally perform well in terms of forgetting scores, we have found that an unexpected model utility drop can occur. This phenomenon, which we term correlation collapse, happens when the machine unlearning algorithms reduce the useful correlation between image features and the true label. To address this challenge, we propose Distribution-Level Feature Distancing (DLFD), a novel method that efficiently forgets instances while preventing correlation collapse. Our method synthesizes data samples so that the generated data distribution is far from the distribution of samples being forgotten in the feature space, achieving significant results even within a single training epoch. Through extensive experiments on facial recognition datasets, we demonstrate that our approach significantly outperforms state-of-the-art machine unlearning methods. All datasets and codes will be publicly available upon acceptance of the paper. All datasets and codes are publicly available after they are accepted.

Distribution-Level Feature Distancing for Machine Unlearning: Towards a Better Trade-off Between Model Utility and Forgetting

Despite significant advancements in image and text conditional image editing, the exploration of using brain signals, which are more direct and personalized to reflect user intentions, remains limited. An intuitive method is to convert implicit brain signals into explicit representations such as images, which can then serve as prompts for editing. However, such two-stage method suffers from low inference efficiency, inaccurate brain interpretation, and unnatural editing results. In this paper, we apply brain signals of visual perception as prompts and propose a cross-modal self-supervised learning for natural image painting (MindPainter). This method achieves efficient and natural brain-conditioned image editing in a straightforward manner. MindPainter is trained for reconstruction from masked images directly with pseudo-brain signals, which is simulated by the proposed Pseudo Brain Generator. It facilitates efficient cross-modal integration. The proposed Brain Adapter further eliminates the gap in implicit space between modalities, ensuring accurate semantic interpretation of brain signals and coherent consolidation. Besides, the designed Multi-Mask Generation Policy enhances the generalization, realizing high-quality editing in various painting scenarios, including inpainting and outpainting. To the best of our knowledge, MindPainter is the first work to achieve efficient brain-conditioned image painting, providing potential for direct brain control in creative AI.

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Enhancing Identity-Deformation Disentanglement in StyleGAN for One-Shot Face Video Re-Enactment

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Enhancing Identity-Deformation Disentanglement in StyleGAN for One-Shot Face Video Re-Enactment

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