1116 research outputs found
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THE GENERALISED HERMITE REGRESSION MODEL: A ROBUST FRAMEWORK FOR EXTREME NONLINEAR DATASETS
No full textNonlinear regression modelling is a fundamental problem in econometrics and applied statistics, particularly for datasets exhibiting heavy tails, skewness, and volatility clustering. Such features are prevalent in many empirical applications and frequently violate the assumptions underlying classical linear regression methods. The central hypothesis of this study is that a regression framework based on orthogonal polynomial expansions can provide improved stability and predictive performance in the presence of pronounced nonlinear behaviour. The motivation for this work arises from the limitations of Ordinary Least Squares regression, which relies on linearity and distributional regularity, and from the instability of standard polynomial regression when applied to heavy-tailed data. To address these issues, the Generalised Hermite Regression Model (GHRM) is proposed by embedding Hermite polynomial expansions into a regression structure, enabling higher-order nonlinear dependencies to be modelled while preserving key theoretical properties. A numerical experiment based on a simulated dataset of 10,000 observations exhibiting nonlinear and heavy-tailed behaviour is conducted to evaluate the proposed model. The GHRM is assessed in comparison with Ordinary Least Squares and cubic polynomial regression using forecasting accuracy measures and information criteria. The results show that Ordinary Least Squares performs poorly under nonlinear conditions, while both polynomial regression and the GHRM achieve substantial improvements in predictive accuracy. Although the two nonlinear models produce comparable numerical results under the cubic specification, the GHRM demonstrates superior structural stability due to the orthogonality of the Hermite basis. These findings establish the GHRM as a robust and scalable framework for modelling nonlinear datasets with complex distributional characteristics
DEVELOPMENT OF A CONTINUOUS MULTI-STEP ONE-FOURTH STEP HYBRID SCHEME FOR THIRD-ORDER IVP IN ORDINARY DIFFERENTIAL EQUATIONS
No full textThis study introduces a hybrid block approach for the approximate solution of initial value problems involving third-order ordinary differential equations. The formulation of the method employs orthogonal and Chebyshev polynomials as basis functions, with its performance enhanced through the incorporation of off-step points. This modification is aimed at achieving zero-stability while maintaining high computational accuracy. Several numerical experiments are carried out to demonstrate the methods effectiveness, and the results confirm its reliability and efficiency in solving such problems
Risk Perceptions of Motor-Insurance Fraud in Nigeria: Insights From Industry Experts
No full textMotor insurance fraud poses a critical threat to the insurer solvency and market integrity, particularly in developing economies where regulatory enforcement and data infrastructure remain weak. In Nigeria, both opportunistic exaggerations (“soft” fraud) and deliberate schemes (“hard” fraud) distort claims performance and erode public confidence in insurance. This study investigates how industry professionals perceive the scale and consequences of fraud, drawing on behavioural and institutional perspectives. Using an expert elicitation methodology, data were obtained through a structured questionnaire administered to 120 insurance experts, including underwriters, claims managers, brokers, and regulators. The findings reveal that systemic weaknesses, such as weak enforcement and cultural tolerance for minor deception, amplify fraud risks. Respondents viewed soft fraud as more frequent but harder to prove, while hard fraud was perceived as less common yet more financially damaging. These results extend existing literature by providing context-specific, empirically grounded evidence from a sub-Saharan African market where reliable claims data are scarce. The study contributes to risk research by demonstrating how perceptions of fraud are shaped by institutional capacity, and it offers actionable implications for enhancing regulatory oversight, improving insurer resilience, and strengthening governance frameworks in emerging insurance markets
Job Satisfaction and Employee Performance in Small-Scale Businesses in Lagos State, Nigeria
No full textThis study examined job satisfaction and employee performance in small-scale businesses in Lagos State, Nigeria. It investigated the dimensions of job satisfaction, including time management, absenteeism, and feedback mechanisms, and their impact on employee performance. A quantitative approach was adopted. The study population comprises fifty (50) respondents drawn from employees of small -scale businesses in Ago Palace Way, Lagos State. A survey design question was administered to employees working in small-scale businesses in Ago Palace Way, Lagos State. The regression analysis indicated that effective time management and regular feedback mechanisms had a positive, statistically significant impact on job satisfaction and employee performance; absenteeism did not significantly influence job satisfaction. The findings suggest that job satisfaction is closely linked to performance levels, with improved time management and feedback processes enhancing both. It highlighted that business owners should invest in employee development, effective communication strategies, regular feedback mechanisms, a positive work environment, productivity, and employee well-being. It also revealed that small-scale businesses could benefit from focusing on job satisfaction through strategic time management and feedback channels. It recommends adopting effective time management strategies, investing in employee development, and establishing regular feedback mechanisms to foster a positive work environment and improve performance
PERFORMANCE EVALUATION OF A COMPUTATIONAL BLOCK METHOD FOR SOLVING QUADRATIC RICCATI DIFFERENTIAL EQUATIONS: A NUMERICAL VALIDATION AND COMPARATIVE ANALYSIS
No full textThis study presents a computational block method derived through interpolation and collocation using power series polynomials for solving quadratic Riccati differential equations (QRDEs). A rigorous analysis of the method's core properties including order, consistency, and stability confirms its theoretical soundness. The method's performance was evaluated by applying it to three benchmark QRDEs. Numerical results demonstrate that the proposed method achieves significantly higher accuracy compared to several existing techniques documented in the literature. The study concludes that the computational block method is an efficient and reliable numerical tool for solving QRDEs, offering superior precision and convergence characteristics
SEMI-ANALYTICAL ITERATIVE METHODS FOR SOLVING TIME-FRACTIONAL RICCATI DIFFERENTIAL EQUATION
No full textIn this paper, two semi-analytical methods for solving the time-fractional Riccati differential equation, the homotopy perturbation method (HPM) and the modified new iterative method (MNIM), are employed to solve the time-fractional Riccati equation, which is characterized by its nonlinear and fractional-order nature, and serves as a fundamental model in mathematical physics and engineering processes involving memory and hereditary properties. By incorporating the Caputo fractional derivative, the study captures the nonlocal temporal dynamics of the system. The MNIM is formulated to enhance convergence and minimize computational complexity, while HPM is utilized to construct an approximate analytical series solution without linearization or discretization. Both methods yield rapidly convergent series solutions that approximate the exact analytical solution with high accuracy. We considered two test cases, and the results demonstrated the efficiency, simplicity, and robustness of the proposed methods for various fractional orders, establishing both methods as powerful tools for fractional nonlinear differential equations in applied sciences and engineering. The paper lies in applying semi-analytical iterative methods tailored to the time-fractional Riccati differential equation, providing accurate approximate solutions with reduced computational complexity
MHD Natural Convection Couette Flow in a Vertical Channel: Effects of Nonlinear Boussinesq Approximation and Suction/Injection
No full textThis study analytically investigates buoyancy driven magnetohydrodynamic (MHD) natural convection Couette flow in a vertical channel, focusing on the effects of the nonlinear Boussinesq approximation, suction/injection and magnetic fields. The nonlinear Boussinesq term captures significant thermal variations beyond linear models, suction/injection modifies boundary-layer thickness and convective transport, and the magnetic field introduces Lorentz-force damping in electrically conducting flows. The governing momentum and energy equations are solved using the Homotopy Perturbation Method (HPM), and the influence of various parameters on velocity and temperature distributions is examined. Results indicate that the nonlinear Boussinesq parameter enhances fluid motion near the moving plate while suppressing it near the stationary plate. Increased Hartmann numbers uniformly dampen velocity due to stronger Lorentz forces, whereas suction/injection modulates flow development by adjusting the boundary layer. The findings highlight the interplay of buoyancy, magnetic suppression and boundary layer control, providing insights for optimizing flow stability and heat transfer in advanced thermal fluid systems
AN APPLICATION OF BANACH’S CONTRACTION PRINCIPLE TO THE NUMERICAL TREATMENT OF NONLINEAR VOLTERRA-FREDHOLM EQUATIONS IN HEALTH DOMAINS
No full textThis paper investigates the numerical approximations of nonlinear Volterra-Fredholm equations, focusing on their bounded solutions over specified regions. The research employed the Banach contraction principle to prove the existence of a unique solution in the space of continuous functions. The integral equations were formulated to model complex interactions in various applications, particularly infectious disease dynamics. Also, some key parameters, like the kernel functions and scalar multipliers were analyzed to ascertain that the contraction mappings conditions are satisfied. The Picard iteration was used to approximate solutions, proving convergence and stability results. The findings showed significance of these mathematical models in dynamic systems and optimizing treatment in healthcare. This work contributes to the existing literature on nonlinear integral equations
An Analytical Investigation of MHD Williamson Fluid Flow over an Inclined Stretching Sheet in a Porous Medium with Non-Uniform Internal Heat Generation and Mixed Convection
No full textThe complex interplay between heat transfer, fluid motion, and porous media permeability plays a pivotal role in numerous physical and engineering applications. In particular, the control of heat generation and absorption under mixed convection has garnered considerable attention due to its relevance in thermofluid systems embedded in permeable structures. This research presents a semi-analytical approach for solving the nonlinear Williamson fluid model, accounting for the combined effects of mixed convection, medium permeability, and non-uniform heat generation. Through similarity transformations, the governing partial differential equations are reduced to a system of ordinary differential equations, which are subsequently solved using Legendre polynomials as basis functions and Gauss-Lobatto collocation points. The resulting algebraic system is handled in Mathematica 11.0, with solution accuracy verified by comparison to results from the classical Runge-Kutta shooting technique. Numerical findings reveal that increasing the Grashof number enhances fluid velocity, while higher porosity intensifies thermal fields but suppresses flow due to increased resistance in the porous medium. Moreover, spatially varying heat generation induces steep thermal gradients, potentially leading to localized thermal stresses. The proposed methodology proves effective for analyzing complex nonlinear fluid dynamics, offering robust insights for applications in energy systems, geophysical flows, and thermal engineering
Health Management Practices and Health Insurance Uptake among Lagos State Civil Servants
No full textHealth insurance is a veritable mechanism for managing health-related costs. Despite its benefits, the uptake of health insurance in Lagos State still remains low. The study examined the effect of health management practices on the uptake of health insurance among Lagos State civil servants. A survey research design was adopted. The population was departmentalised into demand (civil servants) and supply (health care providers). The sample size for the demand was three hundred and ninety-nine (399), and the supply was one hundred and ninety (190), using Taro-Yamane sampling sample size determination. Multistage sampling techniques were adopted. Regression analysis was applied to test the hypotheses. The results indicated significant relationships between health insurance literacy, coverage breadth, and service quality, and health insurance utilisation, demand for health insurance, and access to healthcare, respectively. The study concluded that improved health management practices, such as health insurance literacy, coverage breadth, and service quality, would increase health insurance uptake among Lagos State civil servants. Therefore, health providers in Lagos State should add ancillary benefits to health coverage. The government and its agencies should further create awareness on the usefulness and benefits of health insurance plans.