Afeez Lawal - Academia.edu (original) (raw)

Papers by Afeez Lawal

Research paper thumbnail of Negotiating Access to Health Care for All through Social and Political Accountability: A Qualitative Study in Rural Nigeria

Social Sciences, 2022

Social accountability is an important strategy towards ensuring that political leaders and actors... more Social accountability is an important strategy towards ensuring that political leaders and actors implement the right policies in the interest of the entire society. In 2007, a community-based health insurance programme was implemented in selected rural communities in Kwara State, Nigeria, through collaboration between the Dutch Health Insurance Fund, PharmAccess Foundation, the Kwara State Government, and Hygeia Nigeria Limited to provide access to basic healthcare for the people. After operating for 9 years, the programme stopped in 2016. This paper describes how social and political accountability shaped the introduction, functioning, and stoppage of the CBHI programme. The study adopted a qualitative approach for data collection, particularly in-depth (n = 22) and key informant interviews (n = 32). Findings indicate that the community-based health insurance programme was proposed by the foreign agency and that the state government was instrumental in the stoppage of the programm...

Research paper thumbnail of AJAS / SPAS ISSN 2316-0861 Corrective Measures in Linear Regression Model Plagued with Heteroscedasticity: A Monte Carlo Approach

In the presence of heteroscedasticity, Ordinary Least Squares (OLS) estimators remain unbiased bu... more In the presence of heteroscedasticity, Ordinary Least Squares (OLS) estimators remain unbiased but no longer efficient. The study examined the corrective measures in linear regression model plagued with heteroscedasticity. Four different heteroscedasticity test were examined of which Goldfeld Quandt test perform better when the sample size is small, while Glejser test is appropriate for larger sample sizes. The HC3 results in better inference for small samples and performed equally with other HCCM for large samples. The performance of OLS, WLS and HC3 compared shows that WLS estimator is preferable in parameter estimation if the model is plagued with heteroscedasticity with known functional form.

Research paper thumbnail of A novel design and implementation of crack pattern analysis using image processing

International Journal of Advance Research, Ideas and Innovations in Technology, 2019

Nowadays, cracks are more happening due to environmental changes, In the real-time scenario, crac... more Nowadays, cracks are more happening due to environmental changes, In the real-time scenario, cracks are very common in a wall, bridge, furniture, railway track. Cracks are the black marks that vanish the civil infrastructure. It indicates the safety status and It is typically developed within a few months or years.

Research paper thumbnail of Corrective Measures in Linear Regression Model Plagued with Heteroscedasticity: A Monte Carlo

African Journal of Applied Statistics, 2019

In the presence of heteroscedasticity, Ordinary Least Squares (OLS) estimators remain unbiased bu... more In the presence of heteroscedasticity, Ordinary Least Squares (OLS) estimators remain unbiased but no longer efficient. The study examined the corrective measures in linear regression model plagued with heteroscedasticity. Four different heteroscedasticity test were examined of which Goldfeld Quandt test perform better when the sample size is small, while Glejser test is appropriate for larger sample sizes. The HC3 results in better inference for small samples and performed equally with other HCCM for large samples. The performance of OLS, WLS and HC3 compared shows that WLS estimator is preferable in parameter estimation if the model is plagued with heteroscedasticity with known functional form.

Research paper thumbnail of Exploratory Analysis of Some Sectors of the Economy : A Seemingly Unrelated Regression Approach

African Journal of Applied Statistics, 2019

Research paper thumbnail of Bootstrap Bartlett Adjustment on Decomposed Variance-Covariance Matrix of Seemingly Unrelated Regression Model

Research paper thumbnail of Corrosion cracking of carbon steels of different structure in the hydrogen sulfide environment under static load

Procedia Structural Integrity, 2018

Abstract Hydrogen sulfide corrosion is one of the main reasons of steels destruction in the oil a... more Abstract Hydrogen sulfide corrosion is one of the main reasons of steels destruction in the oil and gas industry. Damages appear as a result of corrosion and hydrogen embrittlement, and corrosion cracking occurs when the load is applied. The influence of the steels structure on its stress corrosion cracking under the loads in hydrogen sulfide environment is insufficiently studied. The aim of the study is to determine the influence of the steels structure on its corrosion, hydrogenation and corrosion cracking in the NACE hydrogen sulfide solution. It was established that the corrosion rate and hydrogenation of steel У8 in the NACE solution grows when the structure dispersion increases from perlite to sorbite, troostite and martensite. The corrosion rate and hydrogenation of steel 45 are the greatest in pearlite-ferrite, while the smallest - in sorbite. The corrosion of steels У8 and 45 in the NACE solution is localized: the average size of the ulcers is 50 ... 80 μm on the steel У8 and 45 ... 65 μm on steel 45. The depth of ulcers is maximal on the steel У8 with the martensite structure (~ 260 μm) and on the steel 45 with the troostite structure (~ 210 μm). Static load (σ = 300 MPa) increases the hydrogenation of steels in the hydrogen sulfide environment. The concentration of hydrogen in steel У8 with troostite structure increases by ~ 1.8 times. The concentration of hydrogen in steel 45 with troostite and martensite structures increases by ~ 1.2...1.3 and by ~ 1.4...1.6 times, respectively. The steel У8 with martensite and perlite structures and steel 45 with troostite structure has the lowest resistance to corrosion cracking. Steels destruction depends on both hydrogen permeation and the corrosion localization, which leads to the increase of the microelectrochemical heterogeneity of the surfaces.

Research paper thumbnail of Asymptotic hitting time for a simple evolutionary model of protein folding

Journal of Applied Probability, 2005

We consider two versions of a simple evolutionary algorithm (EA) model for protein folding at zer... more We consider two versions of a simple evolutionary algorithm (EA) model for protein folding at zero temperature, namely the (1 + 1)-EA on the LeadingOnes problem. In this schematic model, the structure of the protein, which is encoded as a bit-string of length n, is evolved to its native conformation through a stochastic pathway of sequential contact bindings. We study the asymptotic behavior of the hitting time, in the mean case scenario, under two different mutations: the one-flip, which flips a unique bit chosen uniformly at random in the bit-string, and the Bernoulli-flip, which flips each bit in the bit-string independently with probability c/n, for some c ∈ ℝ + (0 ≤ c ≤ n). For each algorithm, we prove a law of large numbers, a central limit theorem, and compare the performance of the two models.

Research paper thumbnail of Game Theoretic Analysis of the Mobile Discount Service of the Offline Retailers

Journal of Society of Korea Industrial and Systems Engineering, 2016

Research paper thumbnail of Negotiating Access to Health Care for All through Social and Political Accountability: A Qualitative Study in Rural Nigeria

Social Sciences, 2022

Social accountability is an important strategy towards ensuring that political leaders and actors... more Social accountability is an important strategy towards ensuring that political leaders and actors implement the right policies in the interest of the entire society. In 2007, a community-based health insurance programme was implemented in selected rural communities in Kwara State, Nigeria, through collaboration between the Dutch Health Insurance Fund, PharmAccess Foundation, the Kwara State Government, and Hygeia Nigeria Limited to provide access to basic healthcare for the people. After operating for 9 years, the programme stopped in 2016. This paper describes how social and political accountability shaped the introduction, functioning, and stoppage of the CBHI programme. The study adopted a qualitative approach for data collection, particularly in-depth (n = 22) and key informant interviews (n = 32). Findings indicate that the community-based health insurance programme was proposed by the foreign agency and that the state government was instrumental in the stoppage of the programm...

Research paper thumbnail of AJAS / SPAS ISSN 2316-0861 Corrective Measures in Linear Regression Model Plagued with Heteroscedasticity: A Monte Carlo Approach

In the presence of heteroscedasticity, Ordinary Least Squares (OLS) estimators remain unbiased bu... more In the presence of heteroscedasticity, Ordinary Least Squares (OLS) estimators remain unbiased but no longer efficient. The study examined the corrective measures in linear regression model plagued with heteroscedasticity. Four different heteroscedasticity test were examined of which Goldfeld Quandt test perform better when the sample size is small, while Glejser test is appropriate for larger sample sizes. The HC3 results in better inference for small samples and performed equally with other HCCM for large samples. The performance of OLS, WLS and HC3 compared shows that WLS estimator is preferable in parameter estimation if the model is plagued with heteroscedasticity with known functional form.

Research paper thumbnail of A novel design and implementation of crack pattern analysis using image processing

International Journal of Advance Research, Ideas and Innovations in Technology, 2019

Nowadays, cracks are more happening due to environmental changes, In the real-time scenario, crac... more Nowadays, cracks are more happening due to environmental changes, In the real-time scenario, cracks are very common in a wall, bridge, furniture, railway track. Cracks are the black marks that vanish the civil infrastructure. It indicates the safety status and It is typically developed within a few months or years.

Research paper thumbnail of Corrective Measures in Linear Regression Model Plagued with Heteroscedasticity: A Monte Carlo

African Journal of Applied Statistics, 2019

In the presence of heteroscedasticity, Ordinary Least Squares (OLS) estimators remain unbiased bu... more In the presence of heteroscedasticity, Ordinary Least Squares (OLS) estimators remain unbiased but no longer efficient. The study examined the corrective measures in linear regression model plagued with heteroscedasticity. Four different heteroscedasticity test were examined of which Goldfeld Quandt test perform better when the sample size is small, while Glejser test is appropriate for larger sample sizes. The HC3 results in better inference for small samples and performed equally with other HCCM for large samples. The performance of OLS, WLS and HC3 compared shows that WLS estimator is preferable in parameter estimation if the model is plagued with heteroscedasticity with known functional form.

Research paper thumbnail of Exploratory Analysis of Some Sectors of the Economy : A Seemingly Unrelated Regression Approach

African Journal of Applied Statistics, 2019

Research paper thumbnail of Bootstrap Bartlett Adjustment on Decomposed Variance-Covariance Matrix of Seemingly Unrelated Regression Model

Research paper thumbnail of Corrosion cracking of carbon steels of different structure in the hydrogen sulfide environment under static load

Procedia Structural Integrity, 2018

Abstract Hydrogen sulfide corrosion is one of the main reasons of steels destruction in the oil a... more Abstract Hydrogen sulfide corrosion is one of the main reasons of steels destruction in the oil and gas industry. Damages appear as a result of corrosion and hydrogen embrittlement, and corrosion cracking occurs when the load is applied. The influence of the steels structure on its stress corrosion cracking under the loads in hydrogen sulfide environment is insufficiently studied. The aim of the study is to determine the influence of the steels structure on its corrosion, hydrogenation and corrosion cracking in the NACE hydrogen sulfide solution. It was established that the corrosion rate and hydrogenation of steel У8 in the NACE solution grows when the structure dispersion increases from perlite to sorbite, troostite and martensite. The corrosion rate and hydrogenation of steel 45 are the greatest in pearlite-ferrite, while the smallest - in sorbite. The corrosion of steels У8 and 45 in the NACE solution is localized: the average size of the ulcers is 50 ... 80 μm on the steel У8 and 45 ... 65 μm on steel 45. The depth of ulcers is maximal on the steel У8 with the martensite structure (~ 260 μm) and on the steel 45 with the troostite structure (~ 210 μm). Static load (σ = 300 MPa) increases the hydrogenation of steels in the hydrogen sulfide environment. The concentration of hydrogen in steel У8 with troostite structure increases by ~ 1.8 times. The concentration of hydrogen in steel 45 with troostite and martensite structures increases by ~ 1.2...1.3 and by ~ 1.4...1.6 times, respectively. The steel У8 with martensite and perlite structures and steel 45 with troostite structure has the lowest resistance to corrosion cracking. Steels destruction depends on both hydrogen permeation and the corrosion localization, which leads to the increase of the microelectrochemical heterogeneity of the surfaces.

Research paper thumbnail of Asymptotic hitting time for a simple evolutionary model of protein folding

Journal of Applied Probability, 2005

We consider two versions of a simple evolutionary algorithm (EA) model for protein folding at zer... more We consider two versions of a simple evolutionary algorithm (EA) model for protein folding at zero temperature, namely the (1 + 1)-EA on the LeadingOnes problem. In this schematic model, the structure of the protein, which is encoded as a bit-string of length n, is evolved to its native conformation through a stochastic pathway of sequential contact bindings. We study the asymptotic behavior of the hitting time, in the mean case scenario, under two different mutations: the one-flip, which flips a unique bit chosen uniformly at random in the bit-string, and the Bernoulli-flip, which flips each bit in the bit-string independently with probability c/n, for some c ∈ ℝ + (0 ≤ c ≤ n). For each algorithm, we prove a law of large numbers, a central limit theorem, and compare the performance of the two models.

Research paper thumbnail of Game Theoretic Analysis of the Mobile Discount Service of the Offline Retailers

Journal of Society of Korea Industrial and Systems Engineering, 2016