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Dinesh Kumar

Publications and source records attributed to Dinesh Kumar.

At least 19 recordsLinked to original sources

Structural Classification of a Graph with Independence Number Five

The independence polynomial of a simple graph $G$ is given by \( I_G(z) = i_0 + i_1 z + i_2 z^2 + \cdots + i_\alpha z^\alpha \), where \( i_\alpha \) denotes the size of a maximum independent set, also called the independence number of the graph. The independence polynomial has the notable feature of being essentially closed under graph composition (lexicographic product). In this paper, we determine the independence polynomials of size five. For a disconnected graph $G$, we exploit the fact that $I_G(z)$ factors as the product of the independence polynomials of the connected components of $G$. Furthermore, we classify all independence polynomials that can occur for such a disconnected graph $G$ and, by examining their component structures, we characterize the disconnected configurations that may arise.

math.CO

A survey on permutable transcendental entire functions and their dynamics

In this paper, we survey important results on the dynamics of permutable transcendental entire functions from 1958 to 2025. We have discussed the forms of transcendental entire functions that could be permutable. We have also discussed the dynamical properties of permutable entire functions. For instance, how the Fatou and Julia sets are related. We have also considered the relation of the subsets which are classified based on the dynamics of the orbit of a point in the complex plane. They are the filled Julia set $K(f)$ (set of points whose orbits remain bounded), the escaping set $I(f)$ (set of points whose orbits escape to infinity) and the bungee set $BU(f)$ (set of points which are neither bounded nor escaping to infinity). The escaping set is further classified based on the speed of escape, namely, the fast escaping set $A(f)$ or other sets such as $I_0(f)$ and $T(f)$, whose definitions are mentioned in this article. We have also discussed the dynamical relations of these sets. The bungee set sometimes contains a wandering domain, and in this article we have discussed the dynamical relations and conditions that dictates whether wandering domains exists or if it is contained within the bungee set.

math.DS

CGMap: A Geospatially Aware Deep Learning Framework for Crop Gap Mapping Using UAV

In India, crop germination is primarily monitored by visual inspection and manual counting, which are prone to errors, despite their crucial role in determining eventual yield potential. This paper highlights a deep learning based pipeline which uses object detection methods and drone imagery to assess and provide a precise count of sugarcane germination in fields. The approch uses a pre-trained AI model to find germinated plant sampling and identify gaps, also known as ``bald spots'', which restricts field productivity. The techniques used here relies on the YOLOV8 architecture, which was trained on a carefully selected dataset of UAV photos taken in various agroclimatic zones of India. Here, we bring upon a novel orientation-normalization technique that uses minimum Spanning Trees (MST) to account for variations in planting geometry, allowing for dependable row and column extraction across a variety of field layouts. By converting detected seedlings into spatial point clouds, emergence gaps can be inferred from the anticipated spacing between plants. A geospatial germination map exported in Well-Known Text (WKT) format is the end result, and it can be easily incorporated into GIS platforms used by sugar mills and agronomists to direct transplant initiatives. Timely interventions based on the insights provided by the algorithm can significantly increase yield, resulting in higher profits. Hence, support proper allocation of resources, avoid wastage, and enhance long-term sustainability.

cs.CV

Results on the postsingular set of compositions of transcendental entire functions

In this paper, we study the dynamics of commuting transcendental entire functions $f$ and $g$, where $g=af^p+b$ with $a,b\in\mathbb{C}$, $p\in\mathbb{N}$, and $a\neq 0,1$. We examine how singular values and postsingular sets behave under composition. Within this framework, we show that if one of the functions is postsingularly finite (respectively, postsingularly bounded, hyperbolic), then the other function also has this property, and so do their compositions. As an application, we derive several results concerning transcendental semigroups, including situations in which Eremenko's conjecture is satisfied.

math.DS

Hybrid Topological Data Analysis and LSTM Networks for Enhanced Network Intrusion Detection Using CIC-IDS2017 Dataset

Network intrusion detection systems (NIDS) are crucial in cybersecurity infrastructure, needing advanced techniques to detect hostile activity in network traffic. This research introduces a hybrid approach that combines Topological Data Analysis (TDA) with Long Short-Term Memory (LSTM) networks to improve anomaly detection in network security. Our multi-layered design combines TDA's persistent homology with LSTM networks to capture topological characteristics of network traffic patterns and simulate temporal sequences. We assessed our methodology using the CIC-IDS2017 dataset, which includes over 2.8 million labelled flows, 77 network variables, and 14 attack categories that reflect modern threat landscapes such as DDoS, brute force, web attacks, penetration, and botnet activities. Integrating Betti curves and persistence diagrams with deep learning architectures enhances feature extraction performance. Our hybrid TDA+LSTM model has an AUC of 1.000 and F1-score of 1.000, with 5-fold cross-validation producing a mean AUC of 1.000 $\pm$ 0.000 and mean F1 of 0.999 $\pm$ 0.001. An ablation research demonstrates the complimentary contributions of topological (F1=0.990) and temporal characteristics (F1=1.000). Comparative research shows that the suggested strategy beats TDA+Random Forest (F1=0.994) and Isolation Forest (F1=0.835) baselines in several attack categories.

cs.CR

Probing Signatures of Right-Handed Neutrinos via $b \to s \nu \bar\nu$ Decays

The recent Belle II measurement of $\mathcal{B}(B^+\to K^+\nu\bar{\nu})$, which deviates from the Standard Model prediction, provides a strong motivation to search for New Physics in $b\to s\nu\bar{\nu}$ transitions. We perform a model-independent analysis within the low-energy effective theory, focusing on dimension-six vector operators involving right-handed neutrinos. Using the Belle II measurement of $\mathcal{B}({B\to K\nu\bar{\nu}})$ together with the upper limit on $\mathcal{B}({B\to K^{*}\nu\bar{\nu}})$, we constrain the new physics interactions. We study the correlation of $\mathcal{B}({B\to K\nu\bar{\nu}})$ with $\mathcal{B}({B\to K^{*}\nu\bar{\nu}})$, $\mathcal{B}({B_s\to\phi\nu\bar{\nu}})$, $\mathcal{B}({\Lambda_b\to\Lambda\nu\bar{\nu}})$, and the longitudinal polarization fraction $F_L^{K^*}$. We find sizeable enhancements in all branching fractions studied, while $F_L^{K^*}$ offers complementary sensitivity to the underlying RHN interaction structure. These results provide testable signatures of right-handed neutrino interactions at Belle~II and LHCb, and at the future FCC-ee experiment.

hep-ph

Holomorphic Neural ODEs with Kolmogorov-Arnold Networks for Interpretable Discovery of Complex Dynamics

Complex dynamical systems governed by holomorphic maps such as $z^2 + c$ exhibit fractal boundaries with extreme sensitivity to initial conditions. Accurately modelling these structures from data requires methods that respect the underlying complex-analytic geometry, yet Multi-Layer Perceptrons (MLPs) within Neural Ordinary Differential Equations (Neural ODEs) lack complex-analytic priors, violate the Cauchy--Riemann conditions, and function as opaque approximators incapable of yielding governing equations. We introduce Holomorphic KAN-ODE, a framework that replaces the MLP with a Kolmogorov-Arnold Network (KAN) whose learnable B-spline activations reside on network edges, and incorporates Cauchy--Riemann equations as a differentiable regularization to preserve holomorphic structure. We evaluate on six families of complex dynamical systems spanning polynomial and transcendental classes. With only 280 parameters ($16\times$ fewer than the MLP baseline), the network achieves velocity-field $R^2 > 0.95$ on all six systems, correctly identifies all six governing symbolic families through automatic spline-to-formula fitting, and reconstructs Julia set fractal boundaries with up to 98.0\% agreement. Crucially, the model exhibits only 4\% MSE degradation under 10\% observation noise versus $15.2\times$ for MLPs, and achieves 90.4\% improvement in transfer learning from quadratic to cubic dynamics. While the MLP attains lower pointwise reconstruction error due to its larger capacity, the KAN uniquely provides interpretable symbolic equations, enforced holomorphic structure, and superior noise resilience, capabilities that are entirely absent in black-box architectures. These results establish KANs as a parameter-efficient, interpretable alternative to MLPs for physics-informed discovery of holomorphic dynamics.

cs.LG

Equality of the dynamical sets of two commuting transcendental entire functions

In this paper, we study the dynamics of commuting transcendental entire functions $f$ and $g$, where $g$ is of the form $af^p + b$ with $a,b \in \C$, $p \in \N$, and $a \neq 0,1$. We establish that the escaping sets, filled Julia sets, and bungee sets of $f$ and $g$ all coincide. As an immediate consequence, we obtain in particular that the Julia sets of $f$ and $g$ are identical. Our theorem extends the 1998 result of Poon and Yang. Furthermore, following Wang and Yang, we consider a non-constant polynomial $Q$ and permutable entire functions $f$ and $g$ satisfying the relation $Q(g)=aQ(f)+b$, where $a(\neq 0,1), b \in \C$. In this more general setting, we also prove that the escaping sets, the filled Julia sets, and the bungee sets of $f$ and $g$ are equal.

math.DS

Probing the Evolution of Dark Energy: A Joint Analysis of DESI DR2, Pantheon+, and Cosmic Chronometers

We investigate several phenomenological dark energy parameterizations using a joint analysis of late-time cosmological observations, including cosmic-chromatometer measurements of the Hubble parameter, DESI DR2 baryon acoustic oscillation data, and the Pantheon+ Type Ia supernova sample. Our results show that allowing for a time-varying dark energy equation of state significantly improves the overall fit compared to $\Lambda$CDM. The present-day equation-of-state parameter departs from the standard cosmological constant value. In contrast, the evolution parameter in two-parameter models tends to be negative, indicating a possible time dependence of dark energy. However, the constraints on the evolution remain moderate, and current data cannot clearly distinguish the specific functional form of dark energy. Model comparison using information criteria suggests that dynamical dark energy models are favored over $\Lambda$CDM, with the most straightforward one-parameter extension emerging as the most parsimonious scenario. These findings indicate a mild preference for dark energy evolution, though future high-precision observations will be required for definitive conclusions.

astro-ph.CO

Fast Large-Scale Model-Based Iterative Tomography via Exploiting Mathematical Structure, Hierarchical Optimization, Smart Initialization, and Distributed GPU Computing

Model-Based Iterative Reconstruction (MBIR) is important because direct methods, such as Filtered Back-Projection (FBP) can introduce significant noise and artifacts in sparse-angle tomography, especially for time-evolving samples. Although MBIR produces high-quality reconstructions through prior-informed optimization, its computational cost has traditionally limited its broader adoption. In previous work, we addressed this limitation by expressing the Radon transform and its adjoint using non-uniform fast Fourier transforms (NUFFTs), reducing computational complexity relative to conventional projection-based methods. We further accelerated computation by employing a multi-GPU system for parallel processing. In this work, we further accelerate our Fourier-domain framework, by introducing four main strategies: (1) a reformulation of the MBIR forward and adjoint operators that exploits their multi-level Toeplitz structure for efficient Fourier-domain computation; (2) an improved initialization strategy that uses back-projected data filtered with a standard ramp filter as the starting estimate; (3) a hierarchical multi-resolution reconstruction approach that first solves the problem on coarse grids and progressively transitions to finer grids using Lanczos interpolation; and (4) a distributed-memory implementation using MPI that enables near-linear scaling on large high-performance computing (HPC) systems. Together, these innovations significantly reduce iteration counts, improve parallel efficiency, and make high-quality MBIR reconstruction practical for large-scale tomographic imaging. These advances open the door to near-real-time MBIR for applications such as in situ, in operando, and time-evolving experiments.

cs.MS

Sustainable and Optimal Harvesting in a Seasonally Harvested Fishery with a Marine Protected Area: A Two-Patch Model with Bang-Bang and Singular Control

We analyze a bioeconomic model for optimal fishery harvesting in a spatially heterogeneous habitat comprising both harvestable and preservation (reserve) zones. The population dynamics are governed by a hybrid system coupling continuous time within-season dynamics -mortality, harvesting, and dispersal -with a discrete-time Beverton-Holt reproduction map. We derive the necessary and sufficient condition $Fr > 1$ for long-term population persistence, where $F$ encapsulates within-season survival including harvesting effects and $r$ is the intrinsic growth rate. Through bifurcation analysis, we demonstrate that marine protected areas (MPAs) significantly expand the sustainable parameter space. Using Pontryagin's Maximum Principle, we characterize the optimal harvesting strategy as a composite Bang-Singular-Bang control. We derive an explicit state-feedback formula for the singular arc and verify its optimality via the Generalized Legendre-Clebsch condition. Numerical simulations reveal that this dynamic strategy significantly outperforms constant maximum-effort policies, yielding higher cumulative revenue while maintaining the population above the critical collapse threshold through a stable "sawtooth" trajectory. Our results highlight that modest preservation (20-30% of habitat) allows for more intensive, profitable harvesting in open zones without risking resource extinction.

math.DS

On the Stability of Discrete Reaction-Diffusion System of Networked Dynamical Systems

We derive a simple sufficient condition for the local asymptotic stability of spatially discrete, continuous-time reaction-diffusion systems of networked dynamical systems at a homogeneous equilibrium point. The framework explicitly accommodates \emph{heterogeneous} local dynamics -- patches at different nodes governed by structurally distinct functional forms -- a setting not covered by the classical bookkeeping reduction of Jansen and Lloyd (2000), which requires identical patch dynamics, nor by the Master Stability Function of Pecora and Carroll (1998), which is restricted to identical nodes. The stability condition separates cleanly into two independent components: (i) a diagonal dominance criterion on the \emph{spatially averaged Jacobian} of the local patch dynamics, verifiable directly from model parameters without computing eigenvalues of the full composite system; and (ii) a lower bound on the algebraic connectivity (Fiedler value) of the network Laplacian, capturing the role of network topology. The resulting sufficient condition holds for purely conservative dispersal (standard graph Laplacians with zero row sums) and does not require any dispersal loss or mortality during transit -- a restrictive assumption appearing in the author's prior work (2021) and many classical multi-patch analyses. The theory is illustrated through metapopulation networks of predator-prey systems with heterogeneous functional responses, including a striking example in which individually unstable patches are stabilized entirely by dispersal connections.

math.DS

On Dynamics of the Bungee set and the Filled Julia set of a Transcendental Semigroup

We have introduced the notion of the bungee set and the filled Julia set of a transcendental semigroup using Fatou-Julia theory. Numerous results of the bungee set of a single transcendental entire function have been generalized to a transcendental semigroup. For a transcendental semigroup having no oscillatory wandering domain, we provide some conditions for the containment of the bungee set inside the Julia set. The filled Julia set has also been explored in the context of a transcendental semigroup, and some of its properties are discussed. We have also explored some new features of the escaping set of a transcendental semigroup. The bungee set of a conjugate semigroup and an abelian transcendental semigroup has also been investigated.

math.DS

A comprehensive study of $\Lambda_c^- \to \Lambda (\to p \pi) \mu^- \bar \nu_{\mu}$ incorporating SMEFT implications and right-handed neutrino

We present a comprehensive analysis of the decay $\Lambda_c^- \to \Lambda(\to p\pi)\,\mu^- \bar\nu_\mu$ within a model-independent effective field theory framework. Previous studies have been restricted to the three-body decay $\Lambda_c^+ \to \Lambda \mu^+ \nu_\mu$ and considered only left-handed neutrinos within the Low-Energy Effective Theory (LEFT). In this work, we extend the analysis to the complete four-body angular distribution for the first time, incorporating the indirect constraints implied by the Standard Model Effective Field Theory (SMEFT) on the LEFT Wilson coefficients. We also include the effects of right-handed neutrino (RHN) operators, enabling a unified treatment of both left- and right-handed neutrino interactions in the $c \to s \mu \nu_\mu$ transition. Using the global bounds derived from LEFT observables and their SMEFT correlations, we study the impact of allowed new-physics scenarios on a variety of observables, including differential decay rates, forward-backward asymmetries, polarization asymmetries of the final-state hadron and lepton, and the angular coefficients (${\cal M}_0$ to ${\cal M}_9$) in the 4-body angular distribution. Our analysis reveals significant deviations from the Standard Model in the observables $\mathcal{P}^\Lambda_L$ and ${\cal M}_1$ for $C^V_{RL}$ and $C^V_{RR}$, and striking $T$-odd effects in ${\cal M}_7$ for complex $C^V_{RL}$. These features provide sensitive probes of vector-type new physics, such as leptoquark or right-handed current models. The predicted patterns can be tested in forthcoming measurements at BESIII, LHCb, and Belle II, where polarization-sensitive observables in $\Lambda_c$ decays are becoming experimentally accessible.

hep-ph

Crystal Growth & Physical Property Characterization of Mixed Topological Insulator BiSbTe$_3$

This article reports the synthesis of a single crystalline mixed topological insulator (TI) BiSbTe$_3$ and its detailed structural and magneto-transport properties. The single crystalline samples of BiSbTe$_3$ are grown by the melt-growth process and characterized by X-ray diffraction (XRD), Energy dispersive X-ray analysis (EDAX) and Raman spectroscopy. The single crystal XRD peaks dictated the growth direction along the c-axis. The Raman spectrum elucidated the characteristic peaks of the mixed topological insulator. The broadening of Raman peaks exhibited the formation of Te-Bi-Te and Te-Sb-Te bonds and associated vibrational modes. The single crystals are characterized by magneto-transport measurements down to 2 K and up to 14 Tesla transverse magnetic field. The residual resistance ratio (R200 K/R0 K) is found to be 3.64, which endorses the metallic nature of the synthesized crystal. The relative resistance turns out to be higher for the mixed TI than the pure TIs i.e., Bi$_2$Te$_3$ or Sb$_2$Te$_3$. The lower Debye temperature (82.64 K) of BiSbTe$_3$ connotes the presence of effective electron-phonon interaction at quite low temperatures in comparison to pure TI, which explains the observed suppression in magnetoresistance (MR) for the mixed TI. At 2 K, an MR of 150 percent is observed for BiSbTe$_3$, which is suppressed in contrast to the pure TIs i.e., Bi$_2$Te$_3$ or Sb$_2$Te$_3$. Though the MR% is suppressed significantly, its non-saturating linear behavior indicates the topological nature of the studied mixed TI. The modified Hikami-Larkin-Nagaoka (HLN) equation analysis of magneto-conductivity of mixed TI revealed that the conductivity has not only a surface states driven 2D component but also contributions from the bulk charge carriers and quantum scattering.

cond-mat.mtrl-sci

Degradation-Aware and Machine Learning-Driven Uncertainty Quantification in Crystal Plasticity Finite Element: Texture-Driven Plasticity in 316L Stainless Steel

The mechanical properties and long-term structural reliability of crystalline materials are strongly influenced by microstructural features such as grain size, morphology, and crystallographic texture. These characteristics not only determine the initial mechanical behavior but also govern the progression of degradation mechanisms, such as strain localization, fatigue damage, and microcrack initiation under service conditions. Variability in these microstructural attributes, introduced during manufacturing or evolving through in-service degradation, leads to uncertainty in material performance. Therefore, understanding and quantifying microstructure-sensitive plastic deformation is critical for assessing degradation risk in high-value mechanical systems. This study presents a first-of-its-kind machine learning-driven framework that couples high-fidelity crystal plasticity finite element (CPFE) simulations with data-driven surrogate modeling to accelerate degradation-aware uncertainty quantification in welded structural alloys. Specifically, the impact of crystallographic texture variability in 316L stainless steel weldments, characterized via high-throughput electron backscatter diffraction (EBSD), is examined through CPFE simulations on calibrated representative volume elements (RVEs). A polynomial chaos expansion-based surrogate model is then trained to efficiently emulate the CPFE response using only 200 simulations, reducing computational cost by several orders of magnitude compared to conventional Monte Carlo analysis. The surrogate enables rapid quantification of uncertainty in stress-strain behavior and identifies texture components such as Cube and Goss as key drivers of degradation-relevant plastic response.

stat.AP

AI-driven Uncertainty Quantification & Multi-Physics Approach to Evaluate Cladding Materials in a Microreactor

The pursuit of enhanced nuclear safety has spurred the development of accident-tolerant cladding (ATC) materials for light water reactors (LWRs). This study investigates the potential of repurposing these ATCs in advanced reactor designs, aiming to expedite material development and reduce costs. The research employs a multi-physics approach, encompassing neutronics, heat transfer, thermodynamics, and structural mechanics, to evaluate four candidate materials (Haynes 230, Zircaloy-4, FeCrAl, and SiC-SiC) within the context of a high-temperature, sodium-cooled microreactor, exemplified by the Kilopower design. While neutronic simulations revealed negligible power profile variations among the materials, finite element analyses highlighted the superior thermal stability of SiC-SiC and the favorable stress resistance of Haynes 230. The high-temperature environment significantly impacted material performance, particularly for Zircaloy-4 and FeCrAl, while SiC-SiC's inherent properties limited its ability to withstand stress loads. Additionally, AI-driven uncertainty quantification and sensitivity analysis were conducted to assess the influence of material property variations on maximum hoop stress. The findings underscore the need for further research into high-temperature material properties to facilitate broader applicability of existing materials to advanced reactors. Haynes 230 is identified as the most promising candidate based on the evaluated criteria.

physics.ins-det