Goto

Collaborating Authors

 Ashanti


The changing surface of the world's roads

Randhawa, Sukanya, Randhawa, Guntaj, Langer, Clemens, Andorful, Francis, Herfort, Benjamin, Kwakye, Daniel, Olchik, Omer, Lautenbach, Sven, Zipf, Alexander

arXiv.org Artificial Intelligence

Resilient road infrastructure is a cornerstone of the UN Sustainable Development Goals. Yet a primary indicator of network functionality and resilience is critically lacking: a comprehensive global baseline of road surface information. Here, we overcome this gap by applying a deep learning framework to a global mosaic of Planetscope satellite imagery from 2020 and 2024. The result is the first global multi-temporal dataset of road pavedness and width for 9.2 million km of critical arterial roads, achieving 95.5% coverage where nearly half the network was previously unclassified. This dataset reveals a powerful multi-scale geography of human development. At the planetary scale, we show that the rate of change in pavedness is a robust proxy for a country's development trajectory (correlation with HDI = 0.65). At the national scale, we quantify how unpaved roads constitute a fragile backbone for economic connectivity. We further synthesize our data into a global Humanitarian Passability Matrix with direct implications for humanitarian logistics. At the local scale, case studies demonstrate the framework's versatility: in Ghana, road quality disparities expose the spatial outcomes of governance; in Pakistan, the data identifies infrastructure vulnerabilities to inform climate resilience planning. Together, this work delivers both a foundational dataset and a multi-scale analytical framework for monitoring global infrastructure, from the dynamics of national development to the realities of local governance, climate adaptation, and equity. Unlike traditional proxies such as nighttime lights, which reflect economic activity, road surface data directly measures the physical infrastructure that underpins prosperity and resilience - at higher spatial resolution.


Human Experts' Evaluation of Generative AI for Contextualizing STEAM Education in the Global South

Nyaaba, Matthew, Nabang, Macharious, Kyeremeh, Patrick, Nantomah, Ibrahim, Owusu-Fordjour, Collins, Ako, Martin, Akanzire, Bismark Nyaaba, Nantomah, Kassim Korah, Issaka, Cecilia, Zhai, Xiaoming

arXiv.org Artificial Intelligence

STEAM education in many parts of the Global South remains abstract and weakly connected to learners sociocultural realities. This study examines how human experts evaluate the capacity of Generative AI (GenAI) to contextualize STEAM instruction in these settings. Using a convergent mixed-methods design grounded in human-centered and culturally responsive pedagogy, four STEAM education experts reviewed standardized Ghana NaCCA lesson plans and GenAI-generated lessons created with a customized Culturally Responsive Lesson Planner (CRLP). Quantitative data were collected with a validated 25-item Culturally Responsive Pedagogy Rubric assessing bias awareness, cultural representation, contextual relevance, linguistic responsiveness, and teacher agency. Qualitative reflections provided additional insight into the pedagogical and cultural dynamics of each lesson. Findings show that GenAI, especially through the CRLP, improved connections between abstract standards and learners lived experiences. Teacher Agency was the strongest domain, while Cultural Representation was the weakest. CRLP-generated lessons were rated as more culturally grounded and pedagogically engaging. However, GenAI struggled to represent Ghana's cultural diversity, often producing surface-level references, especially in Mathematics and Computing. Experts stressed the need for teacher mediation, community input, and culturally informed refinement of AI outputs. Future work should involve classroom trials, broader expert participation, and fine-tuning with Indigenous corpora.


Facilitating Matches on Allocation Platforms

Trabelsi, Yohai, Adiga, Abhijin, Aumann, Yonatan, Kraus, Sarit, Ravi, S. S.

arXiv.org Artificial Intelligence

We consider a setting where goods are allocated to agents by way of an allocation platform (e.g., a matching platform). An "allocation facilitator" aims to increase the overall utility/social-good of the allocation by encouraging (some of the) agents to relax (some of) their restrictions. At the same time, the advice must not hurt agents who would otherwise be better off. Additionally, the facilitator may be constrained by a "bound" (a.k.a. 'budget'), limiting the number and/or type of restrictions it may seek to relax. We consider the facilitator's optimization problem of choosing an optimal set of restrictions to request to relax under the aforementioned constraints. Our contributions are three-fold: (i) We provide a formal definition of the problem, including the participation guarantees to which the facilitator should adhere. We define a hierarchy of participation guarantees and also consider several social-good functions.


Large-Scale Mixed-Traffic and Intersection Control using Multi-agent Reinforcement Learning

Liu, Songyang, Fan, Muyang, Li, Weizi, Du, Jing, Li, Shuai

arXiv.org Artificial Intelligence

Traffic congestion remains a significant challenge in modern urban networks. Autonomous driving technologies have emerged as a potential solution. Among traffic control methods, reinforcement learning has shown superior performance over traffic signals in various scenarios. However, prior research has largely focused on small-scale networks or isolated intersections, leaving large-scale mixed traffic control largely unexplored. This study presents the first attempt to use decentralized multi-agent reinforcement learning for large-scale mixed traffic control in which some intersections are managed by traffic signals and others by robot vehicles. Evaluating a real-world network in Colorado Springs, CO, USA with 14 intersections, we measure traffic efficiency via average waiting time of vehicles at intersections and the number of vehicles reaching their destinations within a time window (i.e., throughput). At 80% RV penetration rate, our method reduces waiting time from 6.17s to 5.09s and increases throughput from 454 vehicles per 500 seconds to 493 vehicles per 500 seconds, outperforming the baseline of fully signalized intersections. These findings suggest that integrating reinforcement learning-based control large-scale traffic can improve overall efficiency and may inform future urban planning strategies.


ZKP-FedEval: Verifiable and Privacy-Preserving Federated Evaluation using Zero-Knowledge Proofs

Commey, Daniel, Appiah, Benjamin, Klogo, Griffith S., Crosby, Garth V.

arXiv.org Artificial Intelligence

Federated Learning (FL) enables collaborative model training on decentralized data without exposing raw data. However, the evaluation phase in FL may leak sensitive information through shared performance metrics. In this paper, we propose a novel protocol that incorporates Zero-Knowledge Proofs (ZKPs) to enable privacy-preserving and verifiable evaluation for FL. Instead of revealing raw loss values, clients generate a succinct proof asserting that their local loss is below a predefined threshold. Our approach is implemented without reliance on external APIs, using self-contained modules for federated learning simulation, ZKP circuit design, and experimental evaluation on both the MNIST and Human Activity Recognition (HAR) datasets. We focus on a threshold-based proof for a simple Convolutional Neural Network (CNN) model (for MNIST) and a multi-layer perceptron (MLP) model (for HAR), and evaluate the approach in terms of computational overhead, communication cost, and verifiability.


A Bayesian Incentive Mechanism for Poison-Resilient Federated Learning

Commey, Daniel, Sarpong, Rebecca A., Klogo, Griffith S., Bagyl-Bac, Winful, Crosby, Garth V.

arXiv.org Artificial Intelligence

Federated learning (FL) enables collaborative model training across decentralized clients while preserving data privacy. However, its open-participation nature exposes it to data-poisoning attacks, in which malicious actors submit corrupted model updates to degrade the global model. Existing defenses are often reactive, relying on statistical aggregation rules that can be computationally expensive and that typically assume an honest majority. This paper introduces a proactive, economic defense: a lightweight Bayesian incentive mechanism that makes malicious behavior economically irrational. Each training round is modeled as a Bayesian game of incomplete information in which the server, acting as the principal, uses a small, private validation dataset to verify update quality before issuing payments. The design satisfies Individual Rationality (IR) for benevolent clients, ensuring their participation is profitable, and Incentive Compatibility (IC), making poisoning an economically dominated strategy. Extensive experiments on non-IID partitions of MNIST and FashionMNIST demonstrate robustness: with 50% label-flipping adversaries on MNIST, the mechanism maintains 96.7% accuracy, only 0.3 percentage points lower than in a scenario with 30% label-flipping adversaries. This outcome is 51.7 percentage points better than standard FedAvg, which collapses under the same 50% attack. The mechanism is computationally light, budget-bounded, and readily integrates into existing FL frameworks, offering a practical route to economically robust and sustainable FL ecosystems.


A Cookbook for Community-driven Data Collection of Impaired Speech in LowResource Languages

Salihs, Sumaya Ahmed, Wiafe, Isaac, Abdulai, Jamal-Deen, Atsakpo, Elikem Doe, Ayoka, Gifty, Cave, Richard, Ekpezu, Akon Obu, Holloway, Catherine, Tomanek, Katrin, Winful, Fiifi Baffoe Payin

arXiv.org Artificial Intelligence

This study presents an approach for collecting speech samples to build Automatic Speech Recognition (ASR) models for impaired speech, particularly, low-resource languages. It aims to democratize ASR technology and data collection by developing a "cookbook" of best practices and training for community-driven data collection and ASR model building. As a proof-of-concept, this study curated the first open-source dataset of impaired speech in Akan: a widely spoken indigenous language in Ghana. The study involved participants from diverse backgrounds with speech impairments. The resulting dataset, along with the cookbook and open-source tools, are publicly available to enable researchers and practitioners to create inclusive ASR technologies tailored to the unique needs of speech impaired individuals. In addition, this study presents the initial results of fine-tuning open-source ASR models to better recognize impaired speech in Akan.


Deploying and Evaluating Multiple Deep Learning Models on Edge Devices for Diabetic Retinopathy Detection

Asare, Akwasi, Gookyi, Dennis Agyemanh Nana, Boateng, Derrick, Wulnye, Fortunatus Aabangbio

arXiv.org Artificial Intelligence

Abstract: Diabetic Retinopathy (DR), a leading cause of vision impairment in individuals with diabetes, affects approximately 34.6% of diabetes patients globally, with the number of cases projected to reach 242 million by 2045 . Traditional DR diagnosis relies on the manual examination of retinal fundus images, which is both time - consuming and resource intensive . This study presents a novel solution using Edge Impulse to deploy multiple deep learning models for real - time DR detection on edge devices . A robust dataset of over 3,662 retinal fundus images, sourced from the Kaggle EyePACS dataset, was curated, and enhanced through preprocessing techniques, including augmentation and normalization. Using TensorFlow, various Convolutional Neural Networks (CNNs), such as MobileNet, ShuffleNet, SqueezeNet, and a custom Deep Neural Network (DNN), were designed, trained, and optimized for edge deployment. The models were converted to TensorFlo w Lite and quantized to 8 - bit integers to reduce their size and enhance inference speed, with minimal trade - offs in accuracy. Performance evaluations across different edge hardware platforms, including smartphones and microcontrollers, highlighted key metrics such as inference speed, accuracy, precision, and resource utilization. MobileNet ach ieved an accuracy of 96.45%, while SqueezeNet demonstrated strong real - time performance with a small model size of 176 KB and latency of just 17 ms on GPU. ShuffleNet and the custom DNN achieved moderate accuracy but excelled in resource efficiency, making them suitable for lower - end devices. This integration of edge AI technology into healthcare presents a scalable, cost - effective solution for early DR detection, providing timely and accurate diagnosis, especially in resource - constrained and remote healthc are settings. Keywords: Diabetic Retinopathy, Edge Impulse, Deep Learning, Microcontroller Units, TensorFlow, Model Quantization, Edge AI 1. INTRODUCTION Diabetes is a significant global health challenge, with rates rising worldwide over the past two decades. One of the major complications of diabetes is Diabetic Retinopathy (DR), a severe eye condition that can lead to vision loss in adults (Maqsood and Gupta, 2022) . DR is caused by damage to the blood vessels in the retina, leading to swelling and leakage, which can impair vision (Saeed, Hussain and Aboalsamh, 2021) . Approximately 34.6% of individuals with diabetes develop DR, making it the leading cause of vision loss among working - age adults (Li et al., 2023) .


Improving Multilingual Math Reasoning for African Languages

Ogundepo, Odunayo, Oladipo, Akintunde, Ogueji, Kelechi, Adenuga, Esther, Adelani, David Ifeoluwa, Lin, Jimmy

arXiv.org Artificial Intelligence

Researchers working on low-resource languages face persistent challenges due to limited data availability and restricted access to computational resources. Although most large language models (LLMs) are predominantly trained in high-resource languages, adapting them to low-resource contexts, particularly African languages, requires specialized techniques. Several strategies have emerged for adapting models to low-resource languages in todays LLM landscape, defined by multi-stage pre-training and post-training paradigms. However, the most effective approaches remain uncertain. This work systematically investigates which adaptation strategies yield the best performance when extending existing LLMs to African languages. We conduct extensive experiments and ablation studies to evaluate different combinations of data types (translated versus synthetically generated), training stages (pre-training versus post-training), and other model adaptation configurations. Our experiments focuses on mathematical reasoning tasks, using the Llama 3.1 model family as our base model.


Large-Scale Analysis of Online Questions Related to Opioid Use Disorder on Reddit

Laud, Tanmay, Kacha-Ochana, Akadia, Sumner, Steven A., Krishnasamy, Vikram, Law, Royal, Schieber, Lyna, De Choudhury, Munmun, ElSherief, Mai

arXiv.org Artificial Intelligence

Opioid use disorder (OUD) is a leading health problem that affects individual well-being as well as general public health. Due to a variety of reasons, including the stigma faced by people using opioids, online communities for recovery and support were formed on different social media platforms. In these communities, people share their experiences and solicit information by asking questions to learn about opioid use and recovery. However, these communities do not always contain clinically verified information. In this paper, we study natural language questions asked in the context of OUD-related discourse on Reddit. We adopt transformer-based question detection along with hierarchical clustering across 19 subreddits to identify six coarse-grained categories and 69 fine-grained categories of OUD-related questions. Our analysis uncovers ten areas of information seeking from Reddit users in the context of OUD: drug sales, specific drug-related questions, OUD treatment, drug uses, side effects, withdrawal, lifestyle, drug testing, pain management and others, during the study period of 2018-2021. Our work provides a major step in improving the understanding of OUD-related questions people ask unobtrusively on Reddit. We finally discuss technological interventions and public health harm reduction techniques based on the topics of these questions.