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Item Hybrid algorithm selection and hyperparameter tuning on distribute machine learning resources: Hierarchical agent-based approach(Association for Computing Machinery, 2024-11-18) Esmaeili, Ahmad; Rayz, Julia; Matson, EricAlgorithm selection and hyperparameter tuning are critical steps in both academic and applied machine learning (ML). These steps are becoming increasingly delicate due to the extensive rise in the number, diversity, and distributed nature of ML resources. Multi-agent systems, when applied to the design of ML platforms, bring about several distinctive characteristics, such as scalability, flexibility, and robustness, just to name a few. This article proposes a fully automatic and collaborative agent-based mechanism for selecting distributed ML algorithms and simultaneously tuning their hyperparameters. Our method builds upon an existing agent-based hierarchical ML platform and augments its query structure to support the aforementioned functionalities without being limited to specific learning, selection, and tuning mechanisms. We have conducted theoretical assessments, formal verification, and analytical study to demonstrate the correctness, resource utilization, and computational efficiency of our technique. According to the results, our solution is algorithmically correct and exhibits linear time and space complexity in relation to the size of available resources. To further verify its correctness and demonstrate its effectiveness and flexibility across a range of algorithmic options and datasets, the article also presents a series of empirical results on a system composed of 24 algorithms and 9 datasets. The findings not only highlight the efficiency and scalability of the proposed approach, but also show its flexibility and openness to responding to the dynamic and distributed ML ecosystem. © 2024 held by the owner/author(s).Item ProActive Deepfake detection using GAN-based visible watermarking(Association for Computing Machinery, 2024-9-12) Nadimpalli, Aakash Varma; Rattani, AjitaWith the advances in generative adversarial networks (GAN), facial manipulations called DeepFakes have caused major security risks and raised severe societal concerns. However, the popular DeepFake passive detection is an ex-post forensics countermeasure and fails in blocking the disinformation spread in advance. Alternatively, precautions such as adding perturbations to the real data for unnatural distorted DeepFake output easily spotted by the human eyes are introduced as proactive defenses. Recent studies suggest that these existing proactive defenses can be easily bypassed by employing simple image transformation and reconstruction techniques when applied to the perturbed real data and the distorted output, respectively. The aim of this article is to propose a novel proactive DeepFake detection technique using GAN-based visible watermarking. To this front, we propose a reconstructive regularization added to the GAN’s loss function that embeds a unique watermark to the assigned location of the generated fake image. Thorough experiments on multiple datasets confirm the viability of the proposed approach as a proactive defense mechanism against DeepFakes from the perspective of detection by human eyes. Thus, our proposed watermark-based GANs prevent the abuse of the pretrained GANs and smartphone apps, available via online repositories, for DeepFake creation for malicious purposes. Further, the watermarked DeepFakes can also be detected by the SOTA DeepFake detectors. This is critical for applications where automatic DeepFake detectors are used for mass audits due to the huge cost associated with human observers examining a large amount of data manually. © 2024 Copyright held by the owner/author(s) Publication rights licensed to ACM.Item Geographic atrophy progression secondary to age-related macular degeneration: Five years of follow-up(SAGE Publications Ltd, 2024-10-24) Sadeghi, Elham; Valsecchi, Nicola; Vupparaboina, Surat Chandra; Mehrotra, Kunaal; Vupparaboina, Kiran Kumar; Bollepalli, Sandeep Chandra; Sahel, Jose-Alain; Eller, Andrew W.; Chhablani, JayPurpose: To study the progression of geographic atrophy (GA) secondary to age-related macular degeneration over a five-year follow-up. Methods: Eyes with GA included to assess demographic data, yearly optical coherence tomography (OCT) findings and the GA growth rate on infra-red (IR) images. Results: A total of 41 eyes of 29 patients were included with a mean age of 81.76 ± 6.37 at baseline, and 65.51% were females. Over five years, there was a significant increase in the mean GA area from 8.44 ± 8.98 mm² to 13.32 ± 10.07 mm² (P < 0.001), with an annual growth rate of 1.14 ± 0.78 mm². The annual growth rates in females were slightly higher compared to males (1.29 ± 0.89 mm2 vs 0.96 ± 0.49 mm2, p = 0.569), and in smokers was slightly higher than non-smokers (1.35 ± 0.85 mm2 vs 0.94 ± 0.66 mm2, p = 0.100). Larger GA areas at the baseline showed higher GA progression in mm2 per year (P = 0.04). Smaller GA areas and fovea-spared GA at the baseline exhibited a larger percentage increase (P < 0.001 and P = 0.015, respectively). There was a lower GA progression rate in eyes with outer retinal tubulations (ORT) (P = 0.027), yet no significant correlation was found between GA progression and other OCT features. Conclusions: Smaller, fovea-sparing GA eyes experienced a more substantial proportional increase over five years. Also, The presence of ORT was associated with a slower rate of GA progression. Additionally, we observed a trend of faster GA growth in smokers and female genders. © The Author(s) 2024.Item Incidence and risk factors of fellow-eyes wet conversion in unilateral neovascular age-related macular degeneration over 15-year follow-up(Springer Science and Business Media Deutschland GmbH, 2024-08-23) Sadeghi, Elham; Vupparaboina, Sharat Chandra; Bollepalli, Sandeep Chandra; Vupparaboina, Kiran; Agarwal, Komal; Sahel, Jose-Alain; Eller, Andrew W.; Chhablani, JayPurpose: Incidence and risk factors of fellow eye wet conversion in unilateral neovascular age-related macular degeneration (nAMD) over 15-years follow-up. Methods: This retrospective study reviewed 593 unilateral nAMD patients with a minimum of five years up to 15-years of follow-up. The demographic data, visual acuity, fellow eye nAMD conversion rate, and the number of anti-vascular endothelial growth factor (anti-VEGF) injections in the primary eye were evaluated. Also, the nAMD-converted fellow eyes were divided into two groups based on the time of conversion (less and more than two years from the first injection in the primary eye). Based on the data types, the T-test, Chi-square, and Mann-Whitney U test were used to analyze. Results: The total cases were 593 patients, and 248 eyes (41.82%) converted to nAMD in the mean interval of 34.92 ± 30.62months. The males exhibited a predisposition to wet conversion at 2.54years earlier than their female counterparts (P = 0.025). In all the converted fellow eyes, the mean age was 2.3years higher at presentation in the group who converted within two years of follow-up in compared to eyes that converted after two years (79.82 ± 8.64 vs 77.51 ± 8.5years, P = 0.035). Additionally, eyes converting within two years had a mean baseline LogMAR visual acuity of 0.44 ± 0.47, compared to 0.32 ± 0.41 for conversions after two years (P = 0.014). Conclusion: This study reported that males showed a predisposition to fellow eye nAMD conversion at an earlier age. Additionally, there was a trend of faster fellow eye nAMD conversion in individuals with higher age and lower baseline visual acuity. Key messages: What is known • Certain risk factors may make the fellow eye of neovascular age-related macular degeneration (nAMD) more likely to progress to wet conversion. • Identifying these risk factors for fellow eye wet conversion can help prevent it, potentially preserving the patient's vision quality for a longer duration. • The studies on the incidence of wet conversion in the fellow eye have yielded controversial results. What is new • During the 15-year follow-up period, nearly half (47.58%) of the fellow eyes that underwent wet conversion did so within the initial two years following the wet conversion of the first eye. • Males showed a predisposition to fellow eye nAMD conversion at an earlier age. • There was a trend of faster fellow eye nAMD conversion in individuals with higher age and lower baseline visual acuity. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.Item On the use of a simulation framework for studying accessibility challenges faced by people with disabilities in indoor environments(Springer Science and Business Media Deutschland GmbH, 2024) Garfias, Francisco R.; Namboodiri, VinodNavigating indoor spaces is known to be significantly challenges for individuals with mobility and sensory impairments due to the presence of physical barriers and inadequate accessible signage. Current laws and efforts have not led to meeting diverse needs of these populations. In this work we provide a brief introduction to MABLESim (Mapping for Accessible BuiLt Environments Simulator), a simulation framework for studying indoor space accessibility. MABLESim recreates digital models of indoor environments, allowing for the simulation of diverse mobility scenarios for individuals with varying abilities. MABLESim enables the analysis of critical factors important for efficient mobility in indoor spaces such as route complexity and disability characteristics. Through careful configuration of simulation parameters, MABLESim facilitates the assessment of accessibility challenges in both simple and complex indoor spaces. This framework offers a tool for designers and planners to visualize and address accessibility barriers in built environments. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.