Africa
Towards a Unified Representation Evaluation Framework Beyond Downstream Tasks
Plachouras, Christos, Guinot, Julien, Fazekas, George, Quinton, Elio, Benetos, Emmanouil, Pauwels, Johan
--Downstream probing has been the dominant method for evaluating model representations, an important process given the increasing prominence of self-supervised learning and foundation models. However, downstream probing primarily assesses the availability of task-relevant information in the model's latent space, overlooking attributes such as equivariance, invariance, and disentanglement, which contribute to the interpretability, adaptability, and utility of representations in real-world applications. While some attempts have been made to measure these qualities in representations, no unified evaluation framework with modular, generalizable, and interpretable metrics exists. In this paper, we argue for the importance of representation evaluation beyond downstream probing. We introduce a standardized protocol to quantify informativeness, equivariance, invariance, and disentanglement of factors of variation in model representations. We use it to evaluate representations from a variety of models in the image and speech domains using different architectures and pretraining approaches on identified controllable factors of variation. We find that representations from models with similar downstream performance can behave substantially differently with regard to these attributes. This hints that the respective mechanisms underlying their downstream performance are functionally different, prompting new research directions to understand and improve representations. Representation learning has become popular across many fields due to its effectiveness, computational efficiency, and the relative simplicity of using representations from pretrained models as features for various downstream tasks. Many architectures, training paradigms, and modalities have been used to learn representations that are effective in a variety of tasks, such as retrieval, classification, and generation.
A Noise-Resilient Semi-Supervised Graph Autoencoder for Overlapping Semantic Community Detection
Bekkair, Abdelfateh, Bellaouar, Slimane, Oulad-Naoui, Slimane
A Noise-Resilient Semi-Supervised Graph Autoencoder for Overlapping Semantic Community Detection Abdelfateh Bekkair, Slimane Bellaouar and Slimane Oulad-Naoui Laboratoire des Mathรฉmatiques et Sciences Appliquรฉes (LMSA), Universitรฉ de Ghardaia, Ghardaia, Algeria Faculty of Sciences and Technology, Universitรฉ de Ghardaia, Ghardaia, AlgeriaA R T I C L E I N F OKeywords: Overlapping community detection Graph attention autoencoder Semi-supervised learning Attributed networks Attribute noise analysis A B S T R A C T Community detection in networks with overlapping structures remains a significant challenge, particularly in noisy real-world environments where integrating topology, node attributes, and prior information is critical. To address this, we propose a semi-supervised graph autoencoder that combines graph multi-head attention and modularity maximization to robustly detect overlapping communities. The model learns semantic representations by fusing structural, attribute, and prior knowledge while explicitly addressing noise in node features. Key innovations include a noise-resistant architecture and a semantic semi-supervised design optimized for community quality through modularity constraints. Experiments demonstrate superior performance the model outperforms state-of-the-art methods in overlapping community detection (improvements in NMI and F1-score) and exhibits exceptional robustness to attribute noise, maintaining stable performance under 60% feature corruption.
Machine learning automorphic forms for black holes
Jejjala, Vishnu, Nampuri, Suresh, Nxumalo, Dumisani, Roy, Pratik, Swain, Abinash
Modular, Jacobi, and mock-modular forms serve as generating functions for BPS black hole degeneracies. By training feed-forward neural networks on Fourier coefficients of automorphic forms derived from the Dedekind eta function, Eisenstein series, and Jacobi theta functions, we demonstrate that machine learning techniques can accurately predict modular weights from truncated expansions. Our results reveal strong performance for negative weight modular and quasi-modular forms, particularly those arising in exact black hole counting formulae, with lower accuracy for positive weights and more complicated combinations of Jacobi theta functions. This study establishes a proof of concept for using machine learning to identify how data is organized in terms of modular symmetries in gravitational systems and suggests a pathway toward automated detection and verification of symmetries in quantum gravity.
Army ditches helicopters for new radical air assault planes
Fox News contributor Brett Velicovich joins'Fox & Friends First' to discuss Secretary's Hegseth's sweeping Army transformation, how Russia has responded to the U.S. minerals deal with Ukraine and the military bolstering drone technology. This is how the Army will island hop in the Pacific to fend off China. And by the way, Chinese President Xi Jinping has nothing like it. With a stunning announcement, the Army did more than ax 40 generals and open the door to AI. The Army bet its future on this radical aircraft, whose engines swivel to take off and land like a helicopter, or fly high and fast like an airplane.
A Benchmark Dataset and a Framework for Urdu Multimodal Named Entity Recognition
Ahmad, Hussain, Zeng, Qingyang, Wan, Jing
The emergence of multimodal content, particularly text and images on social media, has positioned Multimodal Named Entity Recognition (MNER) as an increasingly important area of research within Natural Language Processing. Despite progress in high-resource languages such as English, MNER remains underexplored for low-resource languages like Urdu. The primary challenges include the scarcity of annotated multimodal datasets and the lack of standardized baselines. To address these challenges, we introduce the U-MNER framework and release the Twitter2015-Urdu dataset, a pioneering resource for Urdu MNER. Adapted from the widely used Twitter2015 dataset, it is annotated with Urdu-specific grammar rules. We establish benchmark baselines by evaluating both text-based and multimodal models on this dataset, providing comparative analyses to support future research on Urdu MNER. The U-MNER framework integrates textual and visual context using Urdu-BERT for text embeddings and ResNet for visual feature extraction, with a Cross-Modal Fusion Module to align and fuse information. Our model achieves state-of-the-art performance on the Twitter2015-Urdu dataset, laying the groundwork for further MNER research in low-resource languages.
Dukawalla: Voice Interfaces for Small Businesses in Africa
Ankrah, Elizabeth, Nyairo, Stephanie, Muchai, Mercy, Awori, Kagonya, Ochieng, Millicent, Kariuki, Mark, O'Neill, Jacki
Small and medium sized businesses often struggle with data driven decision making do to a lack of advanced analytics tools, especially in African countries where they make up a majority of the workforce. Though many tools exist they are not designed to fit into the ways of working of SMB workers who are mobile first, have limited time to learn new workflows, and for whom social and business are tightly coupled. To address this, the Dukawalla prototype was created. This intelligent assistant bridges the gap between raw business data, and actionable insights by leveraging voice interaction and the power of generative AI. Dukawalla provides an intuitive way for business owners to interact with their data, aiding in informed decision making. This paper examines Dukawalla's deployment across SMBs in Nairobi, focusing on their experiences using this voice based assistant to streamline data collection and provide business insights
Decomposition of Probabilities of Causation with Two Mediators
Mediation analysis for probabilities of causation (PoC) provides a fundamental framework for evaluating the necessity and sufficiency of treatment in provoking an event through different causal pathways. One of the primary objectives of causal mediation analysis is to decompose the total effect into path-specific components. In this study, we investigate the path-specific probability of necessity and sufficiency (PNS) to decompose the total PNS into path-specific components along distinct causal pathways between treatment and outcome, incorporating two mediators. W e define the path-specific PNS for decomposition and provide an identification theorem. Furthermore, we conduct numerical experiments to assess the properties of the proposed estimators from finite samples and demonstrate their practical application using a real-world educational dataset.
Biomed-DPT: Dual Modality Prompt Tuning for Biomedical Vision-Language Models
Peng, Wei, Liu, Kang, Hu, Jianchen, Zhang, Meng
Prompt learning is one of the most effective paradigms for adapting pre-trained vision-language models (VLMs) to the biomedical image classification tasks in few shot scenarios. However, most of the current prompt learning methods only used the text prompts and ignored the particular structures (such as the complex anatomical structures and subtle pathological features) in the biomedical images. In this work, we propose Biomed-DPT, a knowledge-enhanced dual modality prompt tuning technique. In designing the text prompt, Biomed-DPT constructs a dual prompt including the template-driven clinical prompts and the large language model (LLM)-driven domain-adapted prompts, then extracts the clinical knowledge from the domain-adapted prompts through the knowledge distillation technique. In designing the vision prompt, Biomed-DPT introduces the zero vector as a soft prompt to leverage attention re-weighting so that the focus on non-diagnostic regions and the recognition of non-critical pathological features are avoided. Biomed-DPT achieves an average classification accuracy of 66.14\% across 11 biomedical image datasets covering 9 modalities and 10 organs, with performance reaching 78.06\% in base classes and 75.97\% in novel classes, surpassing the Context Optimization (CoOp) method by 6.20\%, 3.78\%, and 8.04\%, respectively. Our code are available at \underline{https://github.com/Kanyooo/Biomed-DPT}.
Precise gradient descent training dynamics for finite-width multi-layer neural networks
Han, Qiyang, Imaizumi, Masaaki
In this paper, we provide the first precise distributional characterization of gradient descent iterates for general multi-layer neural networks under the canonical single-index regression model, in the `finite-width proportional regime' where the sample size and feature dimension grow proportionally while the network width and depth remain bounded. Our non-asymptotic state evolution theory captures Gaussian fluctuations in first-layer weights and concentration in deeper-layer weights, and remains valid for non-Gaussian features. Our theory differs from existing neural tangent kernel (NTK), mean-field (MF) theories and tensor program (TP) in several key aspects. First, our theory operates in the finite-width regime whereas these existing theories are fundamentally infinite-width. Second, our theory allows weights to evolve from individual initializations beyond the lazy training regime, whereas NTK and MF are either frozen at or only weakly sensitive to initialization, and TP relies on special initialization schemes. Third, our theory characterizes both training and generalization errors for general multi-layer neural networks beyond the uniform convergence regime, whereas existing theories study generalization almost exclusively in two-layer settings. As a statistical application, we show that vanilla gradient descent can be augmented to yield consistent estimates of the generalization error at each iteration, which can be used to guide early stopping and hyperparameter tuning. As a further theoretical implication, we show that despite model misspecification, the model learned by gradient descent retains the structure of a single-index function with an effective signal determined by a linear combination of the true signal and the initialization.
2025 AI Index Report
AI performance on demanding benchmarks continues to improve. Performance of advanced AI systems on new benchmarks introduced in 2023 has increased sharply. AI systems also made major strides in generating high-quality video. AI is increasingly embedded in everyday life. In 2023, the FDA (in the US) approved 223 AI-enabled medical devices, up from just six in 2015.