Nonlinear time series analysis, nonlinear dynamics, and chaos, complex networks, multiplex networks
12
Scopus Publications
226
Scholar Citations
6
Scholar h-index
6
Scholar i10-index
Scopus Publications
Topological Methods for Flight Trajectory Analysis and Planned Path Optimization C. Jeeva Jose, Salviyas Sojan, Geo Mathew Gregory, Arjun Krishnan, Christom Joseph, Jithin Mathews, Rinku Jacob, G. Sreekumar, Joel George, P. B. Vinod Kumar New Mathematics and Natural Computation, 2026 Flight trajectories are typically analyzed using a single reference path, although aircraft rarely follow the same route across different days or seasons due to meteorological and operational factors. This limits the ability of conventional methods to capture systematic and season-dependent variations in flight behavior. To address this limitation, this study applies Topological Data Analysis (TDA) to the trajectories of flight KL1613 between Amsterdam and Istanbul over the period from February 2023 to January 2024. The proposed framework integrates geometric measures, including the Haversine distance, with topological descriptors such as persistence diagrams and persistence landscapes to characterize structural deviations in flight paths. The analysis identifies recurrent one-dimensional topological features corresponding to alternative routing patterns and seasonal variations. Monthly trajectory data are clustered into two dominant groups based on combined geometric and topological similarity, from which representative reference paths are extracted for each month. Cost analysis shows that the proposed monthly reference trajectories consistently reduce fuel consumption and travel time compared to both the planned annual reference route and the actual flown trajectories. These results demonstrate the effectiveness of TDA for capturing seasonal structure in flight trajectories and its potential applicability to large-scale air traffic analysis.
Physiologically interpretable ECG classification using recurrence network topology and amplitude-preserving normalization Sruthi S L, Rinku Jacob, Suresh Davis Aip Advances, 2025 This study proposes a novel normalization method that retains signal-specific amplitude characteristics, improving the differentiation between healthy and unhealthy electrocardiogram (ECG) signals. We present a nonlinear network-based approach to analyze ECG dynamics using a recurrence network (RN), described by characteristic path length, link density, and the clustering coefficient as key network measures. To quantify signal complexity, we introduce weighted Shannon entropy measures based on the distributions of shortest path lengths and clustering coefficients in the RN. Degree heterogeneity is further investigated to examine network-level local node variability between cardiac conditions. A comprehensive analysis using the Physikalisch-Technische Bundesanstalt (PTB) Diagnostic ECG Database of Physionet shows that the proposed approach effectively differentiates between normal and abnormal signals, including bundle branch block, myocardial infarction, dysrhythmias, hypertrophy, and cardiomyopathy even when only the V1 lead is used. The method achieves a classification accuracy of 93.5% for Random Forest and 91.7% with XGBoost, confirming the robustness of recurrence-based features in short-duration ECG analysis. The recurrence-based topological and complexity measures, integrated with the proposed amplitude-preserving normalization, quantitatively agree with physiological mechanisms such as conduction delay, repolarization instability, and morphological irregularity, offering a reliable framework for real-time and clinically useful cardiac diagnosis.
Weighted recurrence networks for the analysis of time-series data Rinku Jacob, K. P. Harikrishnan, R. Misra, G. Ambika Proceedings of the Royal Society A Mathematical Physical and Engineering Sciences, 2019 Recurrence networks (RNs) have become very popular tools for the nonlinear analysis of time-series data. They are unweighted and undirected complex networks constructed with specific criteria from time series. In this work, we propose a method to construct a ‘weighted recurrence network’ from a time series and show that it can reveal useful information regarding the structure of a chaotic attractor which the usual unweighted RN cannot provide. Especially, a network measure, the node strength distribution, from every chaotic attractor follows a power law (with exponential cut off at the tail) with an index characteristic to the fractal structure of the attractor. This provides a new class among complex networks to which networks from all standard chaotic attractors are found to belong. Two other prominent network measures, clustering coefficient and characteristic path length, are generalized and their utility in discriminating chaotic dynamics from noise is highlighted. As an application of the proposed measure, we present an analysis of variable star light curves whose behaviour has been reported to be strange non-chaotic in a recent study. Our numerical results indicate that the weighted recurrence network and the associated measures can become potentially important tools for the analysis of short and noisy time series from the real world.
Cross over of recurrence networks to random graphs and random geometric graphs RINKU JACOB, K P HARIKRISHNAN, R MISRA, G AMBIKA Pramana Journal of Physics, 2017 Recurrence networks are complex networks constructed from the time series of chaotic dynamical systems where the connection between two nodes is limited by the recurrence threshold. This condition makes the topology of every recurrence network unique with the degree distribution determined by the probability density variations of the representative attractor from which it is constructed. Here we numerically investigate the properties of recurrence networks from standard low-dimensional chaotic attractors using some basic network measures and show how the recurrence networks are different from random and scale-free networks. In particular, we show that all recurrence networks can cross over to random geometric graphs by adding sufficient amount of noise to the time series and into the classical random graphs by increasing the range of interaction to the system size. We also highlight the effectiveness of a combined plot of characteristic path length and clustering coefficient in capturing the small changes in the network characteristics.
Weighted recurrence networks from chaotic time series Chaos 2017 Proceedings 10th Chaotic Modeling and Simulation International Conference, 2017
Measure for degree heterogeneity in complex networks and its application to recurrence network analysis Rinku Jacob, K. P. Harikrishnan, R. Misra, G. Ambika Royal Society Open Science, 2017 We propose a novel measure of degree heterogeneity, for unweighted and undirected complex networks, which requires only the degree distribution of the network for its computation. We show that the proposed measure can be applied to all types of network topology with ease and increases with the diversity of node degrees in the network. The measure is applied to compute the heterogeneity of synthetic (both random and scale free (SF)) and real-world networks with its value normalized in the interval [ 0 , 1 ] . To define the measure, we introduce a limiting network whose heterogeneity can be expressed analytically with the value tending to 1 as the size of the network N tends to infinity. We numerically study the variation of heterogeneity for random graphs (as a function of p and N ) and for SF networks with γ and N as variables. Finally, as a specific application, we show that the proposed measure can be used to compare the heterogeneity of recurrence networks constructed from the time series of several low-dimensional chaotic attractors, thereby providing a single index to compare the structural complexity of chaotic attractors.
Topological Methods for Flight Trajectory Analysis and Planned Path Optimization C Jeeva Jose, S Sojan, GM Gregory, A Krishnan, C Joseph, J Mathews, ... New Mathematics and Natural Computation, 1-21 , 2026 2026
Physiologically interpretable ECG classification using recurrence network topology and amplitude-preserving normalization S SL, R Jacob, S Davis AIP Advances 15 (12) , 2025 2025
Tracking Dynamical Transitions using Link Density of Recurrence Networks R Jacob, R Misra, KP Harikrishnan, G Ambika arXiv preprint arXiv:2405.19357 , 2024 2024
Analyzing Electrocardiogram Signal Complexity with Weighted Entropy SL Sruthi, R Jacob International Conference on Nonlinear Dynamics and Applications, 152-163 , 2024 2024
Weighted recurrence networks for the analysis of time-series data R Jacob, KP Harikrishnan, R Misra, G Ambika Proceedings of the Royal Society A: Mathematical, Physical and Engineering … , 2019 2019 Citations: 11
Recurrence network measures for hypothesis testing using surrogate data: Application to black hole light curves KP Harikrishnan, R Jacob, R Misra, G AMBIKA Elsevier BV , 2018 2018
Recurrence network measures for hypothesis testing using surrogate data: Application to black hole light curves R Jacob, KP Harikrishnan, R Misra, G Ambika Communications in Nonlinear Science and Numerical Simulation 54, 84-99 , 2018 2018 Citations: 15
Degree weighted recurrence networks for the analysis of time series data R Jacob, KP Harikrishnan, R Misra, G Ambika arXiv preprint arXiv:1709.05042 , 2017 2017
Determining the minimum embedding dimension for state space reconstruction through recurrence networks KP Harikrishnan, R Jacob, R Misra, G Ambika Indian Academy of Sciences ‘Conference Series 1 (1), 43-49 , 2017 2017 Citations: 3
Cross over of recurrence networks to random graphs and random geometric graphs R Jacob, KP Harikrishnan, R Misra, G Ambika Pramana 88 (2), 37 , 2017 2017 Citations: 6
Measure for degree heterogeneity in complex networks and its application to recurrence network analysis KP Harikrishnan, R Jacob, R Misra, G Ambika Royal Society of Chemistry , 2017 2017 Citations: 1
Weighted recurrence networks from chaotic time series KP Harikrishnan, R Jacob, R Misra, G Ambika Chaotic Model. Simul 4, 433-440 , 2017 2017 Citations: 2
Cross over of recurrence networks to random graphs and random geometric graphs KP Harikrishnan, R Jacob, R Misra, G AMBIKA Springer Nature , 2017 2017
Measure for degree heterogeneity in complex networks and its application to recurrence network analysis R Jacob, KP Harikrishnan, R Misra, G Ambika Royal Society open science 4 (1) , 2017 2017 Citations: 92
Characterization of chaotic attractors under noise: A recurrence network perspective R Jacob, KP Harikrishnan, R Misra, G Ambika Communications in Nonlinear Science and Numerical Simulation 41, 32-47 , 2016 2016 Citations: 26
Can recurrence networks show small-world property? R Jacob, KP Harikrishnan, R Misra, G Ambika Physics Letters A 380 (35), 2718-2723 , 2016 2016 Citations: 12
A new measure of heterogeneity for complex networks. R Jacob, KP Harikrishnan, R Misra, G Ambika arXiv preprint arXiv:1605.06607 , 2016 2016
Characterization of chaotic attractors under noise: A recurrence network perspective KP Harikrishnan, R Jacob, R Misra, G AMBIKA Elsevier BV , 2016 2016
Uniform framework for the recurrence-network analysis of chaotic time series KP Harikrishnan, R Jacob, R Misra, G AMBIKA American Physical Society , 2016 2016
Uniform framework for the recurrence-network analysis of chaotic time series R Jacob, KP Harikrishnan, R Misra, G Ambika Physical review E 93 (1), 012202 , 2016 2016 Citations: 55
MOST CITED SCHOLAR PUBLICATIONS
Measure for degree heterogeneity in complex networks and its application to recurrence network analysis R Jacob, KP Harikrishnan, R Misra, G Ambika Royal Society open science 4 (1) , 2017 2017 Citations: 92
Uniform framework for the recurrence-network analysis of chaotic time series R Jacob, KP Harikrishnan, R Misra, G Ambika Physical review E 93 (1), 012202 , 2016 2016 Citations: 55
Characterization of chaotic attractors under noise: A recurrence network perspective R Jacob, KP Harikrishnan, R Misra, G Ambika Communications in Nonlinear Science and Numerical Simulation 41, 32-47 , 2016 2016 Citations: 26
Recurrence network measures for hypothesis testing using surrogate data: Application to black hole light curves R Jacob, KP Harikrishnan, R Misra, G Ambika Communications in Nonlinear Science and Numerical Simulation 54, 84-99 , 2018 2018 Citations: 15
Can recurrence networks show small-world property? R Jacob, KP Harikrishnan, R Misra, G Ambika Physics Letters A 380 (35), 2718-2723 , 2016 2016 Citations: 12
Weighted recurrence networks for the analysis of time-series data R Jacob, KP Harikrishnan, R Misra, G Ambika Proceedings of the Royal Society A: Mathematical, Physical and Engineering … , 2019 2019 Citations: 11
Cross over of recurrence networks to random graphs and random geometric graphs R Jacob, KP Harikrishnan, R Misra, G Ambika Pramana 88 (2), 37 , 2017 2017 Citations: 6
Determining the minimum embedding dimension for state space reconstruction through recurrence networks KP Harikrishnan, R Jacob, R Misra, G Ambika Indian Academy of Sciences ‘Conference Series 1 (1), 43-49 , 2017 2017 Citations: 3
Fiber Bragg Grating based temperature and strain sensor simulation for biomedical applications G Gopalakrishnan, IM SERENE, R Jacob, G Amit, SK Sudheer, ZC Alex, ... Optoelectronics and Advanced Materials–Rapid Communications 2 (1), 10-14 , 2008 2008 Citations: 3
Weighted recurrence networks from chaotic time series KP Harikrishnan, R Jacob, R Misra, G Ambika Chaotic Model. Simul 4, 433-440 , 2017 2017 Citations: 2
Measure for degree heterogeneity in complex networks and its application to recurrence network analysis KP Harikrishnan, R Jacob, R Misra, G Ambika Royal Society of Chemistry , 2017 2017 Citations: 1
Topological Methods for Flight Trajectory Analysis and Planned Path Optimization C Jeeva Jose, S Sojan, GM Gregory, A Krishnan, C Joseph, J Mathews, ... New Mathematics and Natural Computation, 1-21 , 2026 2026
Physiologically interpretable ECG classification using recurrence network topology and amplitude-preserving normalization S SL, R Jacob, S Davis AIP Advances 15 (12) , 2025 2025
Tracking Dynamical Transitions using Link Density of Recurrence Networks R Jacob, R Misra, KP Harikrishnan, G Ambika arXiv preprint arXiv:2405.19357 , 2024 2024
Analyzing Electrocardiogram Signal Complexity with Weighted Entropy SL Sruthi, R Jacob International Conference on Nonlinear Dynamics and Applications, 152-163 , 2024 2024
Recurrence network measures for hypothesis testing using surrogate data: Application to black hole light curves KP Harikrishnan, R Jacob, R Misra, G AMBIKA Elsevier BV , 2018 2018
Degree weighted recurrence networks for the analysis of time series data R Jacob, KP Harikrishnan, R Misra, G Ambika arXiv preprint arXiv:1709.05042 , 2017 2017
Cross over of recurrence networks to random graphs and random geometric graphs KP Harikrishnan, R Jacob, R Misra, G AMBIKA Springer Nature , 2017 2017
A new measure of heterogeneity for complex networks. R Jacob, KP Harikrishnan, R Misra, G Ambika arXiv preprint arXiv:1605.06607 , 2016 2016
Characterization of chaotic attractors under noise: A recurrence network perspective KP Harikrishnan, R Jacob, R Misra, G AMBIKA Elsevier BV , 2016 2016