yusuke1997/dblp-id-title huggingface dataset:
Generating Chaos in Dynamical Systems: Applications, Symmetry Results, and Stimulating Examples
String Theory Bounds on the Cosmological Constant, the Higgs Mass, and the Quark and Lepton Masses
Fuzzy Reasoning Symmetric Quintuple-Implication Method for Mixed Information and Its Application
Nature, Nurture, and Noise: Developmental Instability, Fluctuating Asymmetry, and the Causes of Phenotypic Variation
Multi-Scale Feature Fusion Based on Difference Enhancement for Remote Sensing Image Change Detection
SOAM Block: A Scale-Orientation-Aware Module for Efficient Object Detection in Remote Sensing Imagery
Applications of the q-Srivastava-Attiya Operator Involving a Certain Family of Bi-Univalent Functions Associated with the Horadam Polynomials
Analysis of Key Elements of Truss Structures Based on the Tangent Stiffness Method
Development and Evaluation of Speech Synthesis System Based on Deep Learning Models
Compromised-Imputation and EWMA-Based Memory-Type Mean Estimators Using Quantile Regression
Hybrid Ćirić Type Graphic Υ, Λ-Contraction Mappings with Applications to Electric Circuit and Fractional Differential Equations
Dynamics of Shunting Inhibitory Cellular Neural Networks with Variable Two-Component Passive Decay Rates and Poisson Stable Inputs
Spontaneous and Explicit Spacetime Symmetry Breaking in Einstein-Cartan Theory with Background Fields
Novel m - Polar Fuzzy Linguistic ELECTRE-I Method for Group Decision-Making
Symmetric Multi-Scale Residual Network Ensemble with Weighted Evidence Fusion Strategy for Facial Expression Recognition
A Fuzzy Multi-Criteria Analysis of Barriers and Policy Strategies for Small and Medium Enterprises to Adopt Green Innovation
A Compression Resistant Steganography Based on Differential Manchester Code
Blind Audio Watermarking Based on Parametric Slant-Hadamard Transform and Hessenberg Decomposition
Classical and Quantum Cosmological Solutions in Teleparallel Dark Energy with Anisotropic Background Geometry
The Fuzzy-AHP Synthesis Model for Energy Security Assessment of the Serbian Natural Gas Sector
Interweaving the Numerical Kinematic Symmetry Principles in School and Introductory University Physics Courses
Symmetry in the Multidimensional Dynamical Analysis of Iterative Methods with Memory
Classification of Negative Information on Socially Significant Topics in Mass Media
A Deterministic and Stochastic Fractional-Order ILSR Rumor Propagation Model Incorporating Media Reports and a Nonlinear Inhibition Mechanism
The Generation of High-Energy Electron-Positron Pairs during the Breit-Wheeler Resonant Process in a Strong Field of an X-ray Electromagnetic Wave
Low Complexity and High Accuracy Estimation of Frequency Offsets for OFDM-Based Cable Transmission Systems
Study of Change-Point Detection and Applications Based on Several Statistical Methods
An Efficient Data Transmission with GSM-MPAPM Modulation for an Indoor VLC System
Stage-Specific Multi-Objective Five-Element Cycle Optimization Algorithm in Green Vehicle-Routing Problem with Symmetric Distance Matrix: Balancing Carbon Emissions and Customer Satisfaction
Blind Color Image Watermarking Using Fan Beam Transform and QR Decomposition
Modular Version of Edge Irregularity Strength for Fan and Wheel Graphs
Leaf Counting with Multi-Scale Convolutional Neural Network Features and Fisher Vector Coding
A Smart 3D RT Method: Indoor Radio Wave Propagation Modelling at 28 GHz
A Symmetric Reversible Audio Information Hiding Algorithm Using Matrix Embedding Within Image Carriers
Key Exchange Protocol Defined over a Non-Commuting Group Based on an NP-Complete Decisional Problem
Common Fixed-Points Technique for the Existence of a Solution to Fractional Integro-Differential Equations via Orthogonal Branciari Metric Spaces
Contextual Modulation in Mammalian Neocortex is Asymmetric
Test-Retest Reliability of the Magnitude and Direction of Asymmetry in the Countermovement Jump, Drop Jump, and Countermovement Rebound Jump
Hand Gesture Recognition with Symmetric Pattern under Diverse Illuminated Conditions Using Artificial Neural Network
A Balance Interface Design and Instant Image-based Traffic Assistant Agent Based on GPS and Linked Open Data Technology
Local-Energy-Conservation-Based Decomposition Method for Wall Friction and Heat Flux
Solutions of the Nonlinear Integral Equation and Fractional Differential Equation Using the Technique of a Fixed Point with a Numerical Experiment in Extended b -Metric Space
An Artwork Rental System Based on Blockchain Technology
Exact Solutions and Conservation Laws of Time-Fractional Levi Equation
Generalized Higher Order Preinvex Functions and Equilibrium-like Problems
Symmetries in Generalized Kaprekar's Routine
Some Results on Neutrosophic Triplet Group and Their Applications
Existence Theory for Nonlinear Third-Order Ordinary Differential Equations with Nonlocal Multi-Point and Multi-Strip Boundary Conditions
Algebraic Structures of Neutrosophic Triplets, Neutrosophic Duplets, or Neutrosophic Multisets
Lagrange-Based Hypergeometric Bernoulli Polynomials
Fingerprint-Based Secure Query Scheme for Databases over Symmetric Mirror Servers
Optical Bistability of Graphene Incorporated into All-Superconducting Photonic Crystals
Primordial Perturbations Including Second-Order Derivatives of the Inflationary Potential
Automatic Parking Path Optimization Based on Immune Moth Flame Algorithm for Intelligent Vehicles
Special Issue: Machine Learning and Data Analysis
New Acoustic Features for Synthetic and Replay Spoofing Attack Detection
Assessment of Conditions for Implementing Information Technology in a Warehouse System: A Novel Fuzzy PIPRECIA Method
A New Parametric Life Family of Distributions: Properties, Copula and Modeling Failure and Service Times
Structural Optimization of a Circular Symmetric Threaded Connection System Based on the Effect of the Upper Stabbing Flank Corner Radius
Multi-Domain Digital Twin and Real-Time Performance Optimization for Marine Steam Turbines
On τ-Pseudo-ν-Convex κ-Fold Symmetric Bi-Univalent Function Family
Characterization of Degree Energies and Bounds in Spectral Fuzzy Graphs
Chemical Composition Optimization of Biocompatible Non-Equiatomic High-Entropy Alloys Using Machine Learning and First-Principles Calculations
Progress on the Stereoselective Synthesis of Chiral Molecules Based on Metal-Catalyzed Dynamic Kinetic Resolution of Alcohols with Lipases
The Dynamics of a Fractional-Order Mathematical Model of Cancer Tumor Disease
Relating Noncommutative SO(2, 3) ★ Gravity to the Lorentz-Violating Standard-Model Extension
Fourth-Order Difference Approximation for Time-Fractional Modified Sub-Diffusion Equation
Revisiting the Schrödinger-Dirac Equation
A Note on the Birnbaum-Saunders Conditionals Model
Thermo-Mechanical Performance of a Phase Change Energy Pile in Saturated Sand
Aero-Engine Borescope Image Defect Detection Algorithm Using Symmetric Feature Extraction and State Space Model
A Continuous Region-Based Skyline Computation for a Group of Mobile Users
Noether Symmetries of Lemaitre-Tolman-Bondi Metric via Rif Tree Approach
Research on Electronic Voltage Transformer for Big Data Background
Codes with Weighted Poset Metrics Based on the Lattice of Subgroups of Zm
A Survey of Public Key Infrastructure-Based Security for Mobile Communication Systems
Reducing Successive Interference Cancellation Iterations in Hybrid Beamforming Multiuser Massive Multiple Input Multiple Output Systems Through Grouping Users with Symmetry Channels
Force Loading Tracking Control of an Electro-Hydraulic Actuator Based on a Nonlinear Adaptive Fuzzy Backstepping Control Scheme
Operator Relationship between Conventional Coupled Cluster and Unitary Coupled Cluster
Synchronous Steady State Solutions of a Symmetric Mixed Cubic-Superlinear Schrödinger System
Fuzzy-System-Based Detection of Pupil Center and Corneal Specular Reflection for a Driver-Gaze Tracking System Based on the Symmetrical Characteristics of Face and Facial Feature Points
Fuzzy System-Based Face Detection Robust to In-Plane Rotation Based on Symmetrical Characteristics of a Face
Loop Representation of Wigner's Little Groups
Fractional Differential Equations and Expansions in Fractional Powers
Intrusion Detection Based on Device-Free Localization in the Era of IoT
The Effects of Computer-Assisted Learning Based on Dual Coding Theory
Research on Green Vehicle Path Planning of AGVs with Simultaneous Pickup and Delivery in Intelligent Workshop
Gate Antiphase of Potassium Channel
Adaptive and Blind Audio Watermarking Algorithm Based on Chaotic Encryption in Hybrid Domain
Unknown Input Observer Scheme for a Class of Nonlinear Generalized Proportional Fractional Order Systems
MFBS: Multiple Factor Bandwidth Strategy Scheme for Anonymity Assessment
Three New Classes of Solvable N -Body Problems of Goldfish Type with Many Arbitrary Coupling Constants
A New Method of Solving Special Solutions of Quaternion Generalized Lyapunov Matrix Equation
Dipole-like Field Configurations in Nonperturbative Vacuum
Order-Theoretic Common Fixed Point Results in Rmb-Metric Spaces
Lightweight Secure Authentication and Key Distribution Scheme for Vehicular Cloud Computing
Multiplicative Brownian Motion Stabilizes the Exact Stochastic Solutions of the Davey-Stewartson Equations
Online Social Networks (OSN) Evolution Model Based on Homophily and Preferential Attachment
An Adaptive Routing-Forwarding Control Scheme Based on an Intelligent Fuzzy Decision-Making System for Opportunistic Social Networks
A Novel Method of Laser Coating Process on Worn-Out Cutter Rings of Tunnel Boring Machine for Eco-Friendly Reuse
The Singularity of Three Kinds of New Tricyclic Graphs
Applications of Gegenbauer Polynomials for Subfamilies of Bi-Univalent Functions Involving a Borel Distribution-Type Mittag-Leffler Function
Personal Data Value Realization and Symmetry Enhancement Under Social Service Orientation: A Tripartite Evolutionary Game Approach
Comparison of Dynamic Performance of an All-Metallic Vibration Isolator by Elliptic Method and Frequency Sweeping Method
Research on the Deposition Characteristics of Integrated Prefabricated Pumping Station
Optimal Design and Singularity Analysis of a Spatial Parallel Manipulator
A Variety of Dynamic Steffensen-Type Inequalities on a General Time Scale
Numerical Contrivance for Kawahara-Type Differential Equations Based on Fifth-Kind Chebyshev Polynomials
Estimating the Variance of Estimator of the Latent Factor Linear Mixed Model Using Supplemented Expectation-Maximization Algorithm
On Bivariate-Balancing and Lucas-Balancing Hybrinomials
Dynamic Marketing Uplift Modeling: A Symmetry-Preserving Framework Integrating Causal Forests with Deep Reinforcement Learning for Personalized Intervention Strategies
Password Authenticated Key Exchange and Protected Password Change Protocols
Anonymous Multi-Receiver Identity-Based Authenticated Encryption with CCA Security
Numerical Study on the Reinforcement Measures of Tunneling on Adjacent Piles
Weak Fault Detection for Gearboxes Using Majorization-Minimization and Asymmetric Convex Penalty Regularization
Application of Fractional Derivative Without Singular and Local Kernel to Enhanced Heat Transfer in CNTs Nanofluid Over an Inclined Plate
Computing the Surface Area of Three-Dimensional Scanned Human Data
Analysis of the Limit Support Pressure of a Shallow Shield Tunnel in Sandy Soil Considering the Influence of Seepage
Enumerating Subtrees of Flower and Sunflower Networks
A Method of Calculation of Non-Homogeneous, Rotationally Symmetric Circular Plates, Supported on Piles
A Sliding Windows Singular Decomposition Model of Monitoring Data for Operational Tunnels
Finely Modulated LDPE/PS Blends via Synergistic Compatibilization with SEBS-g-MAH and OMMT
A Network Security Situational Assessment Method Considering Spatio-Temporal Correlations
Sensitivity Analysis of the Optimal Inventory-Pooling Strategies According to Multivariate Demand Dependence
A Novel Classification Framework for Hyperspectral Image Data by Improved Multilayer Perceptron Combined with Residual Network
Ear Detection under Uncontrolled Conditions with Multiple Scale Faster Region-Based Convolutional Neural Networks
Image Encryption Algorithm Based on Tent Delay-Sine Cascade with Logistic Map
A Motion Control Strategy for a Blind Hexapod Robot Based on Reinforcement Learning and Central Pattern Generator
Nuclear Power Plant Location Selection in Vietnam under Fuzzy Environment Conditions
Some Limiting Measures Related to Free and Boolean Convolutions
An Efficient Algorithm for Solving the Matrix Optimization Problem in the Unsupervised Feature Selection
One-Dimensional Quaternion Fourier Transform with Application to Probability Theory
An Intelligent Based Symmetrical Classification of Online Shop Selling Counterfeit Products
Exact Solutions for Vector Phase-Matching Conditions in Nonlinear Uniaxial Crystals
A Topology Optimization Method Based on Non-Uniform Rational Basis Spline Hyper-Surfaces for Heat Conduction Problems
Transient Dynamic Analysis of Composite Vertical Tail Structures Under Transportation-Induced Vibration Loads
Sparse Fuzzy C-Means Clustering with Lasso Penalty
Calculating Crossing Numbers of Graphs Using Their Redrawings
A High-Accuracy PCB Defect Detection Algorithm Based on Improved YOLOv12
Distribution of Antennal Olfactory and Non-Olfactory Sensilla in Different Species of Bees
A Class of Symmetric Harmonic Functions Involving a Specific q-Difference Symmetric Operator
Separability of the Planar 1/ρ2 Potential in Multiple Coordinate Systems
Some Single-Valued Neutrosophic Power Heronian Aggregation Operators and Their Application to Multiple-Attribute Group Decision-Making
Design of Fast Response Compound Control System for Hypersonic Skid-to-Turn Missile
Propagation and Parametric Amplification in Four-Wave Mixing Processes: Intramolecular Coupling and High-Order Effects
Dual Quaternion Matrix Equation AXB = C with Applications
An Automatic Algorithm to Generate a Reachability Tree for Large-Scale Fuzzy Petri Net by And/Or Graph
CEEMDAN-SVD Motor Noise Reduction Method and Application Based on Underwater Glider Noise Characteristics
Uncertain Time Series Analysis for the Confirmed Case of Brucellosis in China
Anatomical Considerations and Study of the Fractal Dimension around the Posterior Superior Alveolar Artery
Prototiles and Tilings from Voronoi and Delone Cells of the Root Lattice A n
A Semi-Supervised Monocular Stereo Matching Method
Image Inpainting Anti-Forensics Network via Attention-Guided Hierarchical Reconstruction
The Single-Photon Scattering Properties of Three-Level Giant Atoms under the Interaction of Dissipation and Local Coupling
Astrape: An Efficient Concurrent Cloud Attestation with Ciphertext-Policy Attribute-Based Encryption
Determination of Air Traffic Complexity Most Influential Parameters Based on Machine Learning Models
A Chaotic Jerk Oscillator with Complete Control via Fractional Exponentiation and Its Experimental Analog Circuit Realization
Olfactory Laterality Is Valence-Dependent in Mice
Stagnation Point Flow and Heat Transfer over an Exponentially Stretching/Shrinking Sheet in CNT with Homogeneous-Heterogeneous Reaction: Stability Analysis
Tikhonov Regularization Terms for Accelerating Inertial Mann-Like Algorithm with Applications
High-Field Nonresonant Response of Zundel Cations to Intense Terahertz Radiation
Distributed and Asynchronous Population-Based Optimization Applied to the Optimal Design of Fuzzy Controllers
Chaotic Discrete Fractional-Order Food Chain Model and Hybrid Image Encryption Scheme Application
T-Stress Evaluation Based Cracking of Pipes Using an Extended Isogeometric Analysis (X-IGA)
Distributed Integrated Synthetic Adaptive Multi-Objective Reactive Power Optimization
Weight Queue Dynamic Active Queue Management Algorithm
Multi-Scale Pure Graphs with Multi-View Subspace Clustering for Salient Object Detection
Identification of the Ignition Point of High Voltage Cable Trenches Based on Ceiling Temperature Distribution
Semiclassical Spectral Series Localized on a Curve for the Gross-Pitaevskii Equation with a Nonlocal Interaction
The Neutron Lifetime Discrepancy and Its Implications for Cosmology and Dark Matter
A Longitudinal Study of Changes in Fluctuating Asymmetry with Age in Jamaican Youth
On the Evolutionary Form of the Constraints in Electrodynamics
Chaotic Time Series Forecasting Approaches Using Machine Learning Techniques: A Review
Performance Prediction of Air Source Heat Pumps Under Cold and Hot Ambient Temperatures Using ANFIS and ANN Models
Numerical Study of Natural Convection Flow of Nanofluid Past a Circular Cone with Cattaneo-Christov Heat and Mass Flux Models
Advanced Algorithms in Battery Management Systems for Electric Vehicles: A Comprehensive Review
Deep Learning as a Tool for Automatic Segmentation of Corneal Endothelium Images
Dynamics of Fuzzy-Rough Cognitive Networks
Cubane Copper(I) Iodide Clusters with Remotely Functionalized Phosphine Ligands: Synthesis, Structural Characterization and Optical Properties
Towards Generalized Noise-Level Dependent Crystallographic Symmetry Classifications of More or Less Periodic Crystal Patterns
Pattern Recognition of Different Window Size Control Charts Based on Convolutional Neural Network and Information Fusion
Prediction of Tool Point Frequency Response Functions within Machine Tool Work Volume Considering the Position and Feed Direction Dependence
Relationship between Body Composition Asymmetry and Specific Performance in Taekwondo Athletes: A Cross-Sectional Study
Stability of Bounded Dynamical Networks with Symmetry
Scheduling Randomization Protocol to Improve Schedule Entropy for Multiprocessor Real-Time Systems
Complex Dynamics in Circular and Deformed Bilayer Graphene-Inspired Billiards with Anisotropy and Strain
Iterative Algorithms for a System of Variational Inclusions in Banach Spaces
Montgomery Identity and Ostrowski-Type Inequalities for Generalized Quantum Calculus through Convexity and Their Applications
A Puzzle-Based Data Sharing Approach with Cheating Prevention Using QR Code
Improving Multivariate Microaggregation through Hamiltonian Paths and Optimal Univariate Microaggregation
Implicative Neutrosophic Quadruple BCK -Algebras and Ideals
Explicit Runge-Kutta Numerical Manifold Method for Solving the Burgers' Equation via the Hopf-Cole Transformation
The Linguistic Interval-Valued Intuitionistic Fuzzy Aggregation Operators Based on Extended Hamacher T-Norm and S-Norm and Their Application
Detection of Transcoding from H.264/AVC to HEVC Based on CU and PU Partition Types
Identifying D Mesons from Radiative W Decays at the Large Hadron Collider
Khalil New Generalized Weibull Distribution Based on Ranked Samples: Estimation, Mathematical Properties, and Application to COVID-19 Data
Racemization in Post-Translational Modifications Relevance to Protein Aging, Aggregation and Neurodegeneration: Tip of the Iceberg
The Comparative Study for Solving Fractional-Order Fornberg-Whitham Equation via ρ-Laplace Transform
Magnetic Properties of Nickel-Titanium Alloy during Martensitic Transformations under Plastic and Elastic Deformation
Dynamical Properties, Deformations, and Chaos in a Class of Inversion Invariant Jerk Equations
Geographically Weighted Three-Parameters Bivariate Gamma Regression and Its Application
Fractional Landweber Iterative Regularization Method for Solving the Inverse Problem of Time-Fractional Schrödinger Equation
Some Bounds for the Complex Čebyšev Functional of Functions of Bounded Variation
Conflicting Information Fusion Based on an Improved DS Combination Method
Asymmetry Between Queues with Correlated Service and Correlated Arrivals
On Some Symmetries of Quadratic Systems
A Relaxed Inertial Method for Solving Monotone Inclusion Problems with Applications
Modifications of Gravity Via Differential Transformations of Field Variables
Characterizations of Chemical Networks Entropies by K-Banhatii Topological Indices
Sliding Mode Control for Stochastic SIR Models with Telegraph and Lévy Noise: Theory and Applications
Discrete and Continuous Symmetries of Stratified Flows Past a Sphere
A Novel Chaos-Based Color Image Encryption Scheme Using Bit-Level Permutation
An Efficient Algorithm for Eigenvalue Problem of Latin Squares in a Bipartite Min-Max-Plus System
FIGD-Net: A Symmetric Dual-Branch Dehazing Network Guided by Frequency Domain Information
New Numerical Method for the Rotation form of the Oseen Problem with Corner Singularity
A Fault Diagnosis Method for the Train Communication Network Based on Active Learning and Stacked Consistent Autoencoder
The Emergence of Chaos in Quantum Mechanics
A New Generalization of q-Laguerre-Based Appell Polynomials and Quasi-Monomiality
Josephson-like Oscillations in Toroidal Spinor Bose-Einstein Condensates: A Prospective Symmetry Probe
The Impact of Sound Pressure Level, Loudness, Roughness, Sharpness, Articulation Index, Hand Vibration, and Seat Vibration on Subjective Comfort Perception of Tractor Drivers
Bipolar Fuzzy Multi-Criteria Decision-Making Technique Based on Probability Aggregation Operators for Selection of Optimal Artificial Intelligence Framework
On r -Central Incomplete and Complete Bell Polynomials
Developing an Image Manipulation Detection Algorithm Based on Edge Detection and Faster R-CNN
Generalized Dual-Root Lattice Transforms of Affine Weyl Groups
Finite Element Simulation Analysis of the Influence of Pile Spacing on the Uplift Bearing Performance of Concrete Expanding-Plate Pile Groups
A Note on Lower Bounds for Colourful Simplicial Depth
Three-Way Decisions with Interval-Valued Intuitionistic Fuzzy Decision-Theoretic Rough Sets in Group Decision-Making
A Symmetry In-between the Shapes, Shells, and Clusters of Nuclei
A Novel Medical Image Encryption Algorithm Based on High-Dimensional Memristor Chaotic System with Extended Josephus-RNA Hybrid Mechanism
The Exponential-Centred Skew-Normal Distribution
Higher-Order Delay Differential Equation with Distributed Deviating Arguments: Improving Monotonic Properties of Kneser Solutions
On Several Results Associated with the Apéry-like Series
Assessment of Non-Coplanar Maneuver Parameters and Perturbing Accelerations Using the Minimal Number of Observations
Bounds for Extreme Zeros of Classical Orthogonal Polynomials Related to Birth and Death Processes
An Improved Two-Stage Spherical Harmonic ESPRIT-Type Algorithm
Adaptive Fuzzy Fault-Tolerant Control against Time-Varying Faults via a New Sliding Mode Observer Method
Exploring the High-Temperature Electrical Performance of Ca3-xLaxCo4O9 Thermoelectric Ceramics for Moderate and Low Substitution Levels
Studying the Dynamics of the Rumor Spread Model with Fractional Piecewise Derivative
ST-HO: Symmetry-Enhanced Energy-Efficient DAG Task Offloading Algorithm in Intelligent Transport System
Polynomial Decay Rate for Kirchhoff Type in Viscoelasticity with Logarithmic Nonlinearity and Not Necessarily Decreasing Kernel
First and Second Law Thermodynamic Analyses of Hybrid Nanofluid with Different Particle Shapes in a Microplate Heat Exchanger
Background Augmentation Generative Adversarial Networks (BAGANs): Effective Data Generation Based on GAN-Augmented 3D Synthesizing
N = (4, 4) Supersymmetry and T-Duality
High-Intensity Harmonic Generation with Energy Tunability Produced by Robust Two-Color Linearly Polarized Laser Fields
Attribute Network Representation Learning with Dual Autoencoders
Symmetries of Systems with the Same Jacobi Multiplier
An Improved Whale Optimization Algorithm for the Traveling Salesman Problem
Categorical Nonstandard Analysis
Modelling of Red-Mud Particle-Solid Distribution in the Feeder Cup of a Thickener Using the Combined CFD-DPM Approach
Lower Approximation Reduction Based on Discernibility Information Tree in Inconsistent Ordered Decision Information Systems
Short-Term Solar Photovoltaic Power Prediction Utilizing the VMD-BKA-BP Neural Network
Energy of Accelerations Used to Obtain the Motion Equations of a Three- Dimensional Finite Element
Transgenerational Sub-Lethal Pyrethroid Exposure Affects Shape Variation and Fluctuating Asymmetry in Seed Beetles
Lateralization of Auditory Processing of Silbo Gomero
Hybrid Nil Radical of a Ring