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Rasha Shanaz

Publications and source records attributed to Rasha Shanaz.

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Dynamics-Informed Reservoir Computing with Visibility Graphs

Accurate prediction of complex and nonlinear time series remains a challenging problem across engineering and scientific disciplines. Reservoir computing (RC) offers a computationally efficient alternative to traditional deep learning by training only the read-out layer while employing a randomly structured and fixed reservoir network. Despite its advantages, the largely random reservoir graph architecture often results in suboptimal and oversized networks with poorly understood dynamics. Addressing this issue, we propose a novel Dynamics-Informed Reservoir Computing (DyRC) framework that systematically infers the reservoir network structure directly from the input training sequence. This work proposes to employ the visibility graph (VG) technique, which converts time series data into networks by representing measurement points as nodes linked by mutual visibility. The reservoir network is constructed by directly adopting the VG network from a training data sequence, leveraging the parameter-free visibility graph approach to avoid expensive hyperparameter tuning. This process results in a reservoir that is directly informed by the specific dynamics of the prediction task under study. We assess the DyRC-VG method through prediction tasks involving the canonical nonlinear Duffing oscillator, evaluating prediction accuracy and consistency. Compared to an Erdős-Rényi (ER) graph of the same size, spectral radius, and fixed density, we observe higher prediction quality and more consistent performance over repeated implementations in the DyRC-VG. An ER graph with density matched to the DyRC-VG can in some conditions outperform both approaches.

cs.LG

Ethics in rotten apples: A network epidemiology approach for active cyber defense

As Internet of Things (IoT) technology grows, so does the threat of malware infections. A proposed countermeasure, the use of benevolent "white worms" to combat malicious "black worms", presents unique ethical and practical challenges. This study examines these issues via network epidemiology models and simulations, considering the propagation dynamics of both types of worms in various network topologies. Our findings highlight the critical role of the rate at which white worms activate themselves, relative to the user's system update rate, as well as the impact of the network structure on worm propagation. The results point to the potential of white worms as an effective countermeasure, while underscoring the ethical and practical complexities inherent in their deployment.

physics.soc-ph