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Nafisa Anjum

Publications and source records attributed to Nafisa Anjum.

15 recordsLinked to original sources

AGSA-Net: Abundance-Guided Self-Attention Network for Spectral Unmixing-Aware Hyperspectral Remote Sensing Image Classification

Hyperspectral image (HSI) classification plays a vital role in remote sensing applications, including agriculture, environmental monitoring, and urban analysis. However, its performance remains challenged by high spectral redundancy, noise sensitivity, and the difficulty of jointly modeling local material composition and long-range spectral dependencies. To address this, we propose AGSA-Net, an abundance-guided self-attention network that explicitly integrates spectral unmixing priors into the classification process. AGSA Net first estimates physically meaningful subpixel abundance maps subject to non-negativity and sum-to-one constraints, regularized by hybrid linear-nonlinear reconstruction decoder. The learned abundances are then used to construct an abundance affinity prior that guides a spectral transformer to emphasize class-discriminative interactions, and the resulting transformer features are fused with compact abundance descriptors for final prediction; in contrast to existing approaches that use abundance as auxiliary or concatenated features. Experiments on Indian Pines, Augsburg, and Berlin demonstrate the benefit of incorporating abundance- guided contextual modeling, particularly in heterogeneous urban scenes. The source code and trained models are available at: https://github.com/nnuvi/AGSA-Net

cs.CV

XR-PRISM: Data-Driven Privacy and Risk Impact Scoring Metric for Extended Reality in Healthcare

Extended Reality (XR) technologies are transforming healthcare through immersive training, remote consultation, and patient rehabilitation. However, their extensive sensing capabilities and complex data pipelines introduce distinct security, privacy, and safety risks. Existing research lacks a unified quantitative framework for assessing and prioritizing these risks. We review 65 peer-reviewed studies on XR security and privacy published from 2017 to 2024, synthesizing a four-layer threat taxonomy consisting of Device, Network, User, and Cloud layers, along with a corresponding catalog of defenses. Building on this analysis, we introduce XR-PRISM, a six-factor weighted Privacy and Risk Impact Scoring Metric that integrates threat likelihood, system vulnerability, attack surface, safety impact, privacy impact, and control effectiveness into a single actionable risk score. Our analysis shows that more than 70% of the identified countermeasures lack standardized risk evaluation, while fewer than 15% of the documented attacks require a high level of expertise to execute. XR-PRISM provides researchers and practitioners with a transparent, data-driven method for comparing, prioritizing, and mitigating security and privacy risks in healthcare XR deployments.

cs.CR

ECG-Based Stress Prediction with Power Spectral Density Features and Classification Models

Stress has emerged as a critical global health issue, contributing to cardiovascular disorders, depression, and several other long-term illnesses. Consequently, accurate and reliable stress monitoring systems are of growing importance. In this work, we propose a stress prediction framework based on electrocardiogram (ECG) signals recorded during multiple daily activities such as sitting, walking, and jogging. Frequency-domain indicators of autonomic nervous system activity were obtained through Power Spectral Density (PSD) analysis and utilized as input for machine learning models including Decision Tree, Random Forest, XGBoost, LightGBM, and CatBoost. In addition, deep learning approaches, namely Convolutional Neural Networks (CNN) and Long Short-Term Memory (LSTM) networks, were directly applied to the raw ECG signals. Our experiments highlight the effectiveness of ensemble-based classifiers, with CatBoost achieving 90% accuracy. Moreover, the LSTM model provided superior results, attaining 94% accuracy with balanced precision, recall, and F1-score, reflecting its strength in modeling temporal dependencies in ECG data. Overall, the findings suggest that integrating frequency-domain feature extraction with advanced learning algorithms enhances stress prediction and paves the way for real-time healthcare monitoring solutions.

eess.SP

Performance Benchmarking of Machine Learning Models for Terahertz Metamaterial Absorber Prediction

This study presents a polarization-insensitive ultra-broadband terahertz metamaterial absorber based on vanadium dioxide (VO2) and evaluates machine learning methods for predicting its absorption performance. The structure consists of a VO2 metasurface, a MF2 dielectric spacer, and a gold ground plane. It achieves more than 90% absorption between 5.72 and 11.11 THz, covering a 5.38 THz bandwidth with an average absorptance of 98.15%. A dataset of 9,018 samples was generated from full-wave simulations by varying patch width, dielectric thickness, and frequency. Six regression models were trained: Linear Regression, Support Vector Regression, Decision Tree, Random Forest, XGBoost, and Bagging. Performance was measured using adjusted R2, MAE, MSE, and RMSE. Ensemble models achieved the best results, with Bagging reaching an adjusted R2 of 0.9985 and RMSE of 0.0146. The workflow offers a faster alternative to exhaustive simulations and can be applied to other metamaterial designs, enabling efficient evaluation and optimization.

physics.optics

Design and Analysis of a Vanadium Dioxide-Based Ultra-Broadband Terahertz Metamaterial Absorber

This paper presents a VO2-based metamaterial absorber optimized for ultra-broadband, polarization-insensitive performance in the terahertz (THz) frequency range. The absorber consists of a patterned VO2 metasurface, a low-loss MF2 dielectric spacer, and a gold ground plane. Exploiting the phase transition of VO2, the design enables dynamic control of electromagnetic absorption. Full-wave simulations show an average absorptance of 98.15% across a 5.38THz bandwidth (5.72-11.11THz) and over 99% absorption sustained across 3.35THz. The absorber maintains stable performance for varying polarization angles and both TE and TM modes under oblique incidence. Impedance analysis confirms strong matching to free space, reducing reflection and eliminating transmission. Parametric analysis investigates the influence of VO2 conductivity, MF2 thickness, and unit cell periodicity on performance. Compared to recent THz metamaterial absorbers, the proposed design achieves broader bandwidth, higher efficiency, and simpler implementation. These characteristics make it suitable for THz sensing, imaging, wireless communication, and adaptive photonic systems, and position it as a promising platform for tunable and reconfigurable THz modules.

physics.optics

ECOLogic: Enabling Circular, Obfuscated, and Adaptive Logic via eFPGA-Augmented SoCs

Traditional hardware platforms - ASICs and FPGAs - offer competing trade-offs among performance, flexibility, and sustainability. ASICs provide high efficiency but are inflexible post-fabrication, require costly re-spins for updates, and expose IPs to piracy risks. FPGAs offer reconfigurability and reuse, yet suffer from substantial area, power, and performance overheads, resulting in higher carbon footprints. We present ECOLogic, a hybrid design paradigm that embeds lightweight eFPGA fabric within ASICs to enable secure, updatable, and resource-aware computation. Central to this architecture is ECOScore, a quantitative scoring framework that evaluates IPs based on adaptability, piracy threat, performance tolerance, and resource fit to guide RTL partitioning. Evaluated across six diverse SoC modules, ECOLogic retains an average of 90 percent ASIC-level performance (up to 2 GHz), achieves 9.8 ns timing slack (versus 5.1 ns in FPGA), and reduces power by 480 times on average. Moreover, sustainability analysis shows a 99.7 percent reduction in deployment carbon footprint and 300 to 500 times lower emissions relative to FPGA-only implementations. These results position ECOLogic as a high-performance, secure, and environmentally sustainable solution for next-generation reconfigurable systems.

cs.AR

SoK: Securing the Final Frontier for Cybersecurity in Space-Based Infrastructure

With the advent of modern technology, critical infrastructure, communications, and national security depend increasingly on space-based assets. These assets, along with associated assets like data relay systems and ground stations, are, therefore, in serious danger of cyberattacks. Strong security defenses are essential to ensure data integrity, maintain secure operations, and protect assets in space and on the ground against various threats. Previous research has found discrete vulnerabilities in space systems and suggested specific solutions to address them. Such research has yielded valuable insights, but lacks a thorough examination of space cyberattack vectors and a rigorous assessment of the efficacy of mitigation techniques. This study tackles this issue by taking a comprehensive approach to analyze the range of possible space cyber-attack vectors, which include ground, space, satellite, and satellite constellations. In order to address the particular threats, the study also assesses the efficacy of mitigation measures that are linked with space infrastructures and proposes a Risk Scoring Framework. Based on the analysis, this paper identifies potential research challenges for developing and testing cutting-edge technology solutions, encouraging robust cybersecurity measures needed in space.

cs.CR

Design and Optimization of a Metamaterial Absorber for Solar Energy Harvesting in the THz Frequency Range

This paper introduces the design and comprehensive characterization of a novel three-layer metamaterial absorber, engineered to exploit the unique optical properties of gold, vanadium dioxide, and silicon dioxide. At the core of this design, silicon dioxide serves as a robust substrate that supports an intricately structured layer of gold and a top layer of vanadium dioxide. This configuration is optimized to harness and enhance absorption capabilities effectively across a broadband terahertz (THz) spectrum. The absorber demonstrates an extensive absorption bandwidth of 3.00 THz, spanning frequencies from 2.414 THz to 5.417 THz. Remarkably, throughout this range, the device maintains a consistently high absorption efficiency, exceeding 90%. This efficiency is characterized by two sharp absorption peaks located at 2.638 THz and 5.158 THz, which signify the precise tuning of the metamaterial structure to interact optimally with specific THz frequencies. The absorbance of the proposed model is almost equal to 99%. This absorber is polarization insensitive. The development of this absorber involved a series of theoretical simulations backed by experimental validations, which helped refine the metamaterial's geometry and material composition. This process illuminated the critical role of the dielectric properties of silicon dioxide and the plasmonic effects induced by gold and vanadium dioxide layers, which collectively contribute to the high-performance metrics observed.

physics.optics

Ultrasound-Based AI for COVID-19 Detection: A Comprehensive Review of Public and Private Lung Ultrasound Datasets and Studies

The COVID-19 pandemic has affected millions of people globally, with respiratory organs being strongly affected in individuals with comorbidities. Medical imaging-based diagnosis and prognosis have become increasingly popular in clinical settings for detecting COVID-19 lung infections. Among various medical imaging modalities, ultrasound stands out as a low-cost, mobile, and radiation-safe imaging technology. In this comprehensive review, we focus on AI-driven studies utilizing lung ultrasound (LUS) for COVID-19 detection and analysis. We provide a detailed overview of both publicly available and private LUS datasets and categorize the AI studies according to the dataset they used. Additionally, we systematically analyzed and tabulated the studies across various dimensions, including data preprocessing methods, AI models, cross-validation techniques, and evaluation metrics. In total, we reviewed 60 articles, 41 of which utilized public datasets, while the remaining employed private data. Our findings suggest that ultrasound-based AI studies for COVID-19 detection have great potential for clinical use, especially for children and pregnant women. Our review also provides a useful summary for future researchers and clinicians who may be interested in the field.

cs.CV

Benchmarking ChatGPT, Codeium, and GitHub Copilot: A Comparative Study of AI-Driven Programming and Debugging Assistants

With the increasing adoption of AI-driven tools in software development, large language models (LLMs) have become essential for tasks like code generation, bug fixing, and optimization. Tools like ChatGPT, GitHub Copilot, and Codeium provide valuable assistance in solving programming challenges, yet their effectiveness remains underexplored. This paper presents a comparative study of ChatGPT, Codeium, and GitHub Copilot, evaluating their performance on LeetCode problems across varying difficulty levels and categories. Key metrics such as success rates, runtime efficiency, memory usage, and error-handling capabilities are assessed. GitHub Copilot showed superior performance on easier and medium tasks, while ChatGPT excelled in memory efficiency and debugging. Codeium, though promising, struggled with more complex problems. Despite their strengths, all tools faced challenges in handling harder problems. These insights provide a deeper understanding of each tool's capabilities and limitations, offering guidance for developers and researchers seeking to optimize AI integration in coding workflows.

cs.SE

Protecting the Decentralized Future: An Exploration of Common Blockchain Attacks and their Countermeasures

Blockchain technology transformed the digital sphere by providing a transparent, secure, and decentralized platform for data security across a range of industries, including cryptocurrencies and supply chain management. Blockchain's integrity and dependability have been jeopardized by the rising number of security threats, which have attracted cybercriminals as a target. By summarizing suggested fixes, this research aims to offer a thorough analysis of mitigating blockchain attacks. The objectives of the paper include identifying weak blockchain attacks, evaluating various solutions, and determining how effective and effective they are at preventing these attacks. The study also highlights how crucial it is to take into account the particular needs of every blockchain application. This study provides beneficial perspectives and insights for blockchain researchers and practitioners, making it essential reading for those interested in current and future trends in blockchain security research.

cs.CR

Software Supply Chain Vulnerabilities Detection in Source Code: Performance Comparison between Traditional and Quantum Machine Learning Algorithms

The software supply chain (SSC) attack has become one of the crucial issues that are being increased rapidly with the advancement of the software development domain. In general, SSC attacks execute during the software development processes lead to vulnerabilities in software products targeting downstream customers and even involved stakeholders. Machine Learning approaches are proven in detecting and preventing software security vulnerabilities. Besides, emerging quantum machine learning can be promising in addressing SSC attacks. Considering the distinction between traditional and quantum machine learning, performance could be varies based on the proportions of the experimenting dataset. In this paper, we conduct a comparative analysis between quantum neural networks (QNN) and conventional neural networks (NN) with a software supply chain attack dataset known as ClaMP. Our goal is to distinguish the performance between QNN and NN and to conduct the experiment, we develop two different models for QNN and NN by utilizing Pennylane for quantum and TensorFlow and Keras for traditional respectively. We evaluated the performance of both models with different proportions of the ClaMP dataset to identify the f1 score, recall, precision, and accuracy. We also measure the execution time to check the efficiency of both models. The demonstration result indicates that execution time for QNN is slower than NN with a higher percentage of datasets. Due to recent advancements in QNN, a large level of experiments shall be carried out to understand both models accurately in our future research.

cs.CR

COVID-19 Detection using Transfer Learning with Convolutional Neural Network

The Novel Coronavirus disease 2019 (COVID-19) is a fatal infectious disease, first recognized in December 2019 in Wuhan, Hubei, China, and has gone on an epidemic situation. Under these circumstances, it became more important to detect COVID-19 in infected people. Nowadays, the testing kits are gradually lessening in number compared to the number of infected population. Under recent prevailing conditions, the diagnosis of lung disease by analyzing chest CT (Computed Tomography) images has become an important tool for both diagnosis and prophecy of COVID-19 patients. In this study, a Transfer learning strategy (CNN) for detecting COVID-19 infection from CT images has been proposed. In the proposed model, a multilayer Convolutional neural network (CNN) with Transfer learning model Inception V3 has been designed. Similar to CNN, it uses convolution and pooling to extract features, but this transfer learning model contains weights of dataset Imagenet. Thus it can detect features very effectively which gives it an upper hand for achieving better accuracy.

eess.IV

Optimization of Temperature and Relative Humidity in an Automatic Egg Incubator Using Mamdani Interference System

Temperature and humidity are two of the rudimentary factors that must be controlled during egg incubation. Improper temperature and humidity levels during the incubation period often result in unwanted conditions. This paper proposes the design of an efficient Mamdani fuzzy interference system instead of the widely used Takagi-Sugeno system in this field for controlling the temperature and humidity levels of an egg incubator. Though the optimum incubation temperature and humidity levels used here are that of chicken egg, the proposed methodology is applicable to other avian species as well. Theinput functions have been used here as per estimated values forsafe hatching using Mamdani whereas defuzzification method, COA, has been applied for output. From the model output,a stabilized heat from temperature level and fan speed to control the humidity level of an egg incubator can be obtained. This maximizes the hatching rate of healthy chicks under any conditions in the field.

eess.SY

Identifying Counterfeit Products using Blockchain Technology in Supply Chain System

With the advent of globalization and the evergrowing rate of technology, the volume of production as well as ease of procuring counterfeit goods has become unprecedented. Be it food, drug or luxury items, all kinds of industrial manufacturers and distributors are now seeking greater transparency in supply chain operations with a view to deter counterfeiting. This paper introduces a decentralized Blockchain based application system (DApp) with a view to identifying counterfeit products in the supply chain system. With the rapid rise of Blockchain technology, it has become known that data recorded within Blockchain is immutable and secure. Hence, the proposed project here uses this concept to handle the transfer of ownership of products. A consumer can verify the product distribution and ownership information scanning a Quick Response (QR) code generated by the DApp for each product linked to the Blockchain.

cs.CR