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Very High-Resolution Forest Mapping with TanDEM-X InSAR Data and Self-Supervised Learning

arXiv.org Artificial Intelligence

Deep learning models have shown encouraging capabilities for mapping accurately forests at medium resolution with TanDEM-X interferometric SAR data. Such models, as most of current state-of-the-art deep learning techniques in remote sensing, are trained in a fully-supervised way, which requires a large amount of labeled data for training and validation. In this work, our aim is to exploit the high-resolution capabilities of the TanDEM-X mission to map forests at 6 m. The goal is to overcome the intrinsic limitations posed by midresolution products, which affect, e.g., the detection of narrow roads within vegetated areas and the precise delineation of forested regions contours. To cope with the lack of extended reliable reference datasets at such a high resolution, we investigate self-supervised learning techniques for extracting highly informative representations from the input features, followed by a supervised training step with a significantly smaller number of reliable labels. A 1 m resolution forest/non-forest reference map over Pennsylvania, USA, allows for comparing different training approaches for the development of an effective forest mapping framework with limited labeled samples. We select the best-performing approach over this test region and apply it in a real-case forest mapping scenario over the Amazon rainforest, where only very few labeled data at high resolution are available. In this challenging scenario, the proposed self-supervised framework significantly enhances the classification accuracy with respect to fully-supervised methods, trained using the same amount of labeled data, representing an extremely promising starting point for large-scale, very high-resolution forest mapping with TanDEM-X data.


Explosions, huge fire in Sudanese city of Port Sudan

Al Jazeera

Multiple explosions have been heard and a huge fire seen in Port Sudan, though the exact locations and causes were unclear, as Sudan's civil war rocks the previously quiet city for the third day. Dark plumes of smoke could be seen emerging from the vicinity of the country's main maritime port in the city, where hundreds of thousands of displaced people have sought refuge. Al Jazeera's Hiba Morgan, reporting from the Sudanese capital, Khartoum, said residents in the port city reported that attack drones launched by the paramilitary Rapid Support Forces (RSF) hit a fuel depot and other targets. "According to the residents, they believe that it was drone strikes by the paramilitary Rapid Support Forces – once again. They targeted a fuel depot in the city but also around the port and the air base," Morgan said.


Data Augmentation With Back translation for Low Resource languages: A case of English and Luganda

arXiv.org Artificial Intelligence

In this paper,we explore the application of Back translation (BT) as a semi-supervised technique to enhance Neural Machine Translation(NMT) models for the English-Luganda language pair, specifically addressing the challenges faced by low-resource languages. The purpose of our study is to demonstrate how BT can mitigate the scarcity of bilingual data by generating synthetic data from monolingual corpora. Our methodology involves developing custom NMT models using both publicly available and web-crawled data, and applying Iterative and Incremental Back translation techniques. We strategically select datasets for incremental back translation across multiple small datasets, which is a novel element of our approach. The results of our study show significant improvements, with translation performance for the English-Luganda pair exceeding previous benchmarks by more than 10 BLEU score units across all translation directions. Additionally, our evaluation incorporates comprehensive assessment metrics such as SacreBLEU, ChrF2, and TER, providing a nuanced understanding of translation quality. The conclusion drawn from our research confirms the efficacy of BT when strategically curated datasets are utilized, establishing new performance benchmarks and demonstrating the potential of BT in enhancing NMT models for low-resource languages.


Learning Local Causal World Models with State Space Models and Attention

arXiv.org Machine Learning

World modelling, i.e. building a representation of the rules that govern the world so as to predict its evolution, is an essential ability for any agent interacting with the physical world. Despite their impressive performance, many solutions fail to learn a causal representation of the environment they are trying to model, which would be necessary to gain a deep enough understanding of the world to perform complex tasks. With this work, we aim to broaden the research in the intersection of causality theory and neural world modelling by assessing the potential for causal discovery of the State Space Model (SSM) architecture, which has been shown to have several advantages over the widespread Transformer. We show empirically that, compared to an equivalent Transformer, a SSM can model the dynamics of a simple environment and learn a causal model at the same time with equivalent or better performance, thus paving the way for further experiments that lean into the strength of SSMs and further enhance them with causal awareness.


Towards Cross-Modality Modeling for Time Series Analytics: A Survey in the LLM Era

arXiv.org Machine Learning

The proliferation of edge devices has generated an unprecedented volume of time series data across different domains, motivating various well-customized methods. Recently, Large Language Models (LLMs) have emerged as a new paradigm for time series analytics by leveraging the shared sequential nature of textual data and time series. However, a fundamental cross-modality gap between time series and LLMs exists, as LLMs are pre-trained on textual corpora and are not inherently optimized for time series. Many recent proposals are designed to address this issue. In this survey, we provide an up-to-date overview of LLMs-based cross-modality modeling for time series analytics. We first introduce a taxonomy that classifies existing approaches into four groups based on the type of textual data employed for time series modeling. We then summarize key cross-modality strategies, e.g., alignment and fusion, and discuss their applications across a range of downstream tasks. Furthermore, we conduct experiments on multimodal datasets from different application domains to investigate effective combinations of textual data and cross-modality strategies for enhancing time series analytics. Finally, we suggest several promising directions for future research. This survey is designed for a range of professionals, researchers, and practitioners interested in LLM-based time series modeling.


Bayesian Robust Aggregation for Federated Learning

arXiv.org Machine Learning

Federated Learning enables collaborative training of machine learning models on decentralized data. This scheme, however, is vulnerable to adversarial attacks, when some of the clients submit corrupted model updates. In real-world scenarios, the total number of compromised clients is typically unknown, with the extent of attacks potentially varying over time. To address these challenges, we propose an adaptive approach for robust aggregation of model updates based on Bayesian inference. The mean update is defined by the maximum of the likelihood marginalized over probabilities of each client to be `honest'. As a result, the method shares the simplicity of the classical average estimators (e.g., sample mean or geometric median), being independent of the number of compromised clients. At the same time, it is as effective against attacks as methods specifically tailored to Federated Learning, such as Krum. We compare our approach with other aggregation schemes in federated setting on three benchmark image classification data sets. The proposed method consistently achieves state-of-the-art performance across various attack types with static and varying number of malicious clients.


Bayesian Federated Cause-of-Death Classification and Quantification Under Distribution Shift

arXiv.org Artificial Intelligence

In regions lacking medically certified causes of death, verbal autopsy (VA) is a critical and widely used tool to ascertain the cause of death through interviews with caregivers. Data collected by VAs are often analyzed using probabilistic algorithms. The performance of these algorithms often degrades due to distributional shift across populations. Most existing VA algorithms rely on centralized training, requiring full access to training data for joint modeling. This is often infeasible due to privacy and logistical constraints. In this paper, we propose a novel Bayesian Federated Learning (BFL) framework that avoids data sharing across multiple training sources. Our method enables reliable individual-level cause-of-death classification and population-level quantification of cause-specific mortality fractions (CSMFs), in a target domain with limited or no local labeled data. The proposed framework is modular, computationally efficient, and compatible with a wide range of existing VA algorithms as candidate models, facilitating flexible deployment in real-world mortality surveillance systems. We validate the performance of BFL through extensive experiments on two real-world VA datasets under varying levels of distribution shift. Our results show that BFL significantly outperforms the base models built on a single domain and achieves comparable or better performance compared to joint modeling.


Transfer Learning-Based Deep Residual Learning for Speech Recognition in Clean and Noisy Environments

arXiv.org Artificial Intelligence

Addressing the detrimental impact of non-stationary environmental noise on automatic speech recognition (ASR) has been a persistent and significant research focus. Despite advancements, this challenge continues to be a major concern. Recently, data-driven supervised approaches, such as deep neural networks, have emerged as promising alternatives to traditional unsupervised methods. With extensive training, these approaches have the potential to overcome the challenges posed by diverse real-life acoustic environments. In this light, this paper introduces a novel neural framework that incorporates a robust frontend into ASR systems in both clean and noisy environments. Utilizing the Aurora-2 speech database, the authors evaluate the effectiveness of an acoustic feature set for Mel-frequency, employing the approach of transfer learning based on Residual neural network (ResNet). The experimental results demonstrate a significant improvement in recognition accuracy compared to convolutional neural networks (CNN) and long short-term memory (LSTM) networks. They achieved accuracies of 98.94% in clean and 91.21% in noisy mode.


Revealed: What the most stereotypical MEN around the world look like, according to AI - so, do you think they're accurate?

Daily Mail - Science & tech

If you were asked to visualise a stereotypical British man, what would you think of? According to AI, the answer is an overweight man wearing a football shirt. Instagram account @reimagineuk asked AI to create videos of the most stereotypical men around the world - with hilarious results. While the British man looks casual in his football shirt, men from other countries are depicted with fancier outfits. The stereotypical man from Portugal sports a white shirt and a waistcoat, while the man from Nigeria can be seen wearing a bright orange suit.


Constrained Network Adversarial Attacks: Validity, Robustness, and Transferability

arXiv.org Artificial Intelligence

While machine learning has significantly advanced Network Intrusion Detection Systems (NIDS), particularly within IoT environments where devices generate large volumes of data and are increasingly susceptible to cyber threats, these models remain vulnerable to adversarial attacks. Our research reveals a critical flaw in existing adversarial attack methodologies: the frequent violation of domain-specific constraints, such as numerical and categorical limits, inherent to IoT and network traffic. This leads to up to 80.3% of adversarial examples being invalid, significantly overstating real-world vulnerabilities. These invalid examples, though effective in fooling models, do not represent feasible attacks within practical IoT deployments. Consequently, relying on these results can mislead resource allocation for defense, inflating the perceived susceptibility of IoT-enabled NIDS models to adversarial manipulation. Furthermore, we demonstrate that simpler surrogate models like Multi-Layer Perceptron (MLP) generate more valid adversarial examples compared to complex architectures such as CNNs and LSTMs. Using the MLP as a surrogate, we analyze the transferability of adversarial severity to other ML/DL models commonly used in IoT contexts. This work underscores the importance of considering both domain constraints and model architecture when evaluating and designing robust ML/DL models for security-critical IoT and network applications.