Nana Kena Frempong

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• PhD Mathematical Statistics
• Professor (Associate) at Kwame Nkrumah University of Science and Technology

Geometry plays a crucial role in mathematics education, yet Ghanaian senior high school students consistently struggle with mastering geometric concepts, particularly circle theorems. This study investigates the effectiveness of the jigsaw cooperative learning strategy in enhancing students' comprehension and performance in circle theorems. Guided...

Probability distributions offer the best description of survival data and as a result, various lifetime models have been proposed. However, some of these survival datasets are not followed or sufficiently fitted by the existing proposed probability distributions. This paper presents a novel Kumaraswamy Odd Ramos-Louzada-G (KumORL-G) family of distr...

Classical estimation methods of the rate parameter of the gamma distribution have shown to have quality issues. In this paper we propose three estimators namely linear shrinkage, preliminary test and linear shrinkage preliminary test for rate parameter of the gamma distribution using maximum likelihood estimation as a baseline estimator. The salien...

In snakebite envenoming research, occurrences of snakebite are predominantly in the poor, rural communities within the tropical and subtropical countries throughout the world. The most affected in health are the people who engage in agricultural or pastoral activities living in those areas. In recent times, there are increasing in cost and the burd...

This study examines the use of a highly effective training method to conduct one-class classification. The existence of both positive and negative examples in the training data is necessary to develop an effective classifier in common binary classification scenarios. Unfortunately, these criteria are not met in many domains. Here, there is just one...

Several standard distributions can be used to model lifetime data. Nevertheless, a number of these datasets from diverse fields such as engineering, finance, the environment, biological sciences, and others may not fit the standard distributions. As a result, there is a need to develop new distributions that incorporate a high degree of skewness an...

In this study, we have proposed a new generator called the Odd Ramos-Louzada Generator (ORL-G), which can extend many well-known distributions by applying the T-X method. Some of its basic statistical properties such as the quantile function, the non-central moments, and Renyi entropy are also investigated. The ORL-G has the ability to model symme...

In this extant paper, a multivariate time series model using the seemingly unrelated times series equation (SUTSE) framework is proposed to forecast the peak and short-term electricity demand using time series data from February 2, 2014, to August 2, 2018. Further the Markov Chain Monte Carlo (MCMC) method, Gibbs Sampler, together with the Kalman F...

Data recorded from monitoring the health condition of industrial equipment are often high-dimensional, nonlinear, nonstationary and characterised by high levels of uncertainty. These factors limit the efficiency of machine learning techniques to produce desirable results when developing effective fault classification frameworks. This paper sought t...

The Ghana stock market is considered attractive to both local and international investors, as it is a developing market with potential for growth. The volatility of stock returns is one of the crucial features of Ghana's stock market that should be carefully taken into account by any investor or policymaker. As a result, the GARCH, TGARCH, and EGAR...

Empirical evidence suggests that the traditional GARCH-type models are unable to accurately estimate the volatility of financial markets. To improve on the accuracy of the traditional GARCH-type models, a hybrid model (BSGARCH (1, 1)) that combines the flexibility of B-splines with the GARCH (1, 1) model has been proposed in the study. The lagged r...

This study proposes a modified Geometric Brownian motion (GBM), to simulate stock price paths under normal and convoluted distributional assumptions. This study utilised four selected continuous probability distributions for the convolution because of shared properties, including normality, and parameters that have a standard distribution with a lo...

With the rising demand for integrated and autonomous systems in the field of engineering, efficient frameworks for instant detection of performance anomalies are imperative for improved productivity and cost-effectiveness. This study proposes a systematic predictive maintenance framework based on the hybrid multisensor fusion technique of fuzzy rou...

Knowledge of the dependence between random variables is necessary in the area of risk assessment and evaluation. Some of the existing Archimedean copulas, namely the Clayton and the Gumbel copulas, allow for higher correlations on the extreme left and right, respectively. In this study, we use the idea of convex combinations to build a hybrid Clayt...

In this paper, an intelligent Predictive Maintenance (PdM) framework with an efficient and automated selection of relevant and most informative features has been proposed for fault classification. This was achieved by using the hybrid of Fuzzy Set and Rough Set Theories as a feature selection technique for pre-processing and the selection of featur...

Background: Current studies show early interventions of autism increase significant long-term positive effects, symptoms and, later skills. Currently, These interventions are based on the use of an early diagnostic test. Existing methods for diagnosing Autism Spectrum Disorders (ASDs) such as cognitive tests, Intelligence Quotient, and standardized...

This paper uses publicly available data and various statistical models to estimate the basic reproduction number (R0) and other disease parameters for Ghana’s early COVID-19 pandemic outbreak. We also test the effectiveness of government imposition of public health measures to reduce the risk of transmission and impact of the pandemic, especially i...

Data recorded from monitoring the health condition of industrial equipment are often high-dimensional, nonlinear, nonstationary and characterised by high levels of uncertainty. These factors limit the efficiency of machine learning techniques to produce desirable results when developing effective fault classification frameworks. This paper sought t...

In this paper we proposed three estimators namely linear shrinkage, preliminary test and shrinkage preliminary test for the rate parameter of univariate gamma. The salient feature of the proposed estimators is the admissibility property that is defined on belief of the uncertain prior information. Expressions for bias and relative efficiency under...

This paper uses publicly available data and various statistical models to estimate the basic reproduction number (R0) and other disease parameters for the early COVID-19 pandemic outbreak in Ghana. We also test the effectiveness of government imposition of public health measures to reduce the risk of transmission and impact of the pandemic, especia...

Considering the complexities and challenges in the classification of multiclass and imbalanced fault conditions, this study explores the systematic combination of unsupervised and supervised learning by hybridising clustering (CLUST) and optimised multi-layer perceptron neural network with grey wolf algorithm (GWO-MLP). The hybrid technique was met...

In the last two decades, a number of modified and new measures of skewness have been introduced for population data. Tajuddin (2016) attempted to examine the performance of different measures of skewness. In this paper, we seek to examine the performance of Holgersson, Pearson, Classical and Tajuddin Skewness measures based on bias by a simulation...

The interaction of different alloying elements has a significant impact on the mechanical and microstructural properties of steel products due to the thermodynamic and kinetic effect. This article presents a statistically developed and validated model for austenite decomposition during cooling, based on a set of experimental continuous cooling tran...

In this paper, the objective was to study differential factors that explains the mortality rates of male pensioners, comparing the survival patterns of early and normal retirees through a non-parametric approach and a Cox-Proportional Hazard model .The data used was obtained from the Social Security and National Insurance Trust (SSNIT)-Ghana which...

The study of mechanisms and transport of proteins inside cells provide understanding of the dynamics of biological systems and give clues to biological effect of drugs on our system. Reaction-diffusion mechanisms inside cells control various cell functions from adhesion, haptotaxis, chemotaxis to cytoskeletal rearrangement. The theoretical model pr...

The aim of this study is to estimate the age-dependent force of infection for hepatitis B virus (HBV) for sick patients showing symptoms, blood donors and people coming to the serology department to test for the antigen in blood voluntarily. A secondary data was obtained from the serology department at the Komfo Anokye Teaching Hospital (KATH, Janu...

This study exploits the closure property of the converse convolution operator to come up with a hybrid Clayton-Frank Archimedean copula for two random variables. Pairs of random variables were generated and the upper tail observation of the cumulative distribution function (CDF) was used to assess the right skew behavior of the proposed model. Vari...

The aim of this study is to determine the best mixture model for claim amount from a comprehensive insurance policy portfolio and use the model to estimate the expected claim amount per risk for the coming calendar year. The claims data were obtained from the motor insurance office of one of the top business insurance companies in Ghana. The data c...

In Ghana Demographic Health Survey (GDHS), information is collected on the demographic characteristics and health status which is representative sample of the entire population. The backbone for the survey is enumeration areas (EA), clusters which was done using two-stage probabilistic approach. This paper illustrates analysis of childhood mortalit...

The objective of this study is to develop a predictive model that can predict the likelihood of claim given some possible risk factors on the occurrence of claims from the insurance industry. The decision trees analysis was adopted and a predictive model was developed. The model developed took into account the class of portfolios at the individual...

Purpose Being able to predict the likelihood of a project to overrun its cost before the contract signing phase is crucial in developing the required mitigating measures to avert it. Known parameters that permit the timely prediction of cost overrun provide the basis for such predictions. Therefore, the purpose of this paper is to develop a model f...

The study focused on the likelihood of a pair of random variables having either an Archimedean copula or an Elliptical copula. The study involved simulating several pairs of random variables and the bicopselect () function in R was used to select an appropriate bivariate copula family for simulated pairs of random variables. The corresponding param...

The simple random walk with mixed barriers at state $ 0 $ and state $ n $ defined on non-negative integers has transition matrix $ P $ with transition probabilities $ p_{ij} $. Matrix $ Q $ is obtained from matrix $ P $ when rows and columns at state $ 0 $ and state $ n $ are deleted . The fundamental matrix $ B $ is the inverse of the matrix $ A =...

Purpose Time overruns are commonplace within the construction industry. These result in deception because project managers critically assess the economic and financial viability of a project before implementation. Forecasting the likelihood of time overruns will not only lead to a reconsideration on the decision to build but also help put in place...

Sometimes, people with interest in measuring quality of education take into account level in academic performance and various associated factors. Usually, an average academic performance is an accustomed way of assessment; however, this study examines on individual basis different factors that might have an impact on the academic performance of und...

Road accident fatalities have been analyzed over the past decades in many countries. Specifically Ghana, not many studies have looked at the occurrence and incidence of road accident fatalities due to any possible risk exposures. In this study we seek to identify possible significant risk factors on the occurrence and incidence of road accident fat...

The study investigated the presence of volatility in two insurance companies listed on the Ghana Stock Exchange. In checking for the presence of volatility, several ARIMA (p,d,q) models were fitted separately to the log return series of the two companies and the best model selected using the AIC and BIC selection criterion. Using the selected ARIMA...

In this paper, we propose and analyze a new fractional order malaria model with temporary immunity. We extend the existing malaria model to include fractional derivatives. Basic reproduction number is computed using the next generation matrix method. Model equilibria are determined and their local asymptotic stability analysis are considered. An ef...

The main objective of this paper is to formulate an epidemiological model using fractional order derivatives which has an advantage over the classical integer order models due to its memory effect property. Our mathematical formulation of the non-integer order initial value problem will be based on the famous fractional order Caputo derivative. We...

In this paper, we consider an epidemic model of Ebola disease which is deadly in its transmission. Local stability analysis of the model equilibria was investigated. We computed the basic reproduction number í µí±… 0 using the next generation method. The threshold parameter í µí±… 0 was found to be dependent on several hosts of model parameters in...

This research article focuses on the formulation of a treatment model of hepatitis epidemic of type B. The dynamics of the model were studied and the local stability analyses of the equilibrium points of the model were investigated. Lyapunov functions were defined for the equilibrium points and their global stabilities were performed. It was shown...

The aim of this study is to empirically estimate the sensitivity of inflation and interest rate together with some key macroeconomic variables on real economic activity index. Secondly, to investigate the direction of causality between inflation and interest rate, interest rate and real economic activity index, as well as between inflation and real...

The research aimed at developing a groundwater recharge model from available and reliable data of recharge predictor variables from 1985-2009 for the Sumanpa catchment in the forest-savannah transitional zone. Streamflow data for the Sumanpa River was generated from daily stage data using the rating curve model developed by the researchers at the g...

The study examined and modeled stock market volatility of financial return series for three listed equities on the Ghana Stock Exchange (GSE). A historical data from 25th June 2007 to 31st October 2014 was considered for the analysis. The series for each of the three equities were tested for stationarity using the KPSS test. Series found to be non-...

In this paper, we consider two univariate time series models of predicting the dynamics of the exchange rate (using mid-rate data) of the Ghana cedi to the US dollar over a 10year 2months period from January 2004, to February 2015. We consider out-of-sample forecast for the next three years of the exchange rate. The time series models considered fo...

This study examines on an average different factors that might have an impact on the academic performance of undergraduate students. Data on the Semester Weighted Average (SWA) of Class of 2012 Mathematics students was acquired from the Quality Assurance and Planning Unit (QAPU) and the Examination Office of the Department of Mathematics, Kwame Nkr...

The objective of this study was to examine the stability of disease free and endemic equilibria based on the basic reproductive number R 0 and the dynamics of infection at high borrowing rate of Injecting Drug Users (IDU). A deterministic compartmental model for Hepatitis C virus (HCV) infection was adopted from Kretzschmar and Wiessing, 2006. It h...

Survey research has been widely used in public opinion research in Ghana. Ghanaian researchers are happy about data richness and they are also concerned about data quality. In this paper Item Response Theory (IRT) has been used to identify the most appropriate IRT model for understanding item. The techniques are appropriate and practical. A questio...

This paper illustrates analysis of longitudinal data on students' academic performance using GEE (Generalize Estimation Equations) under various working correlation assumptions. Many factors account for students' academic performance in the fulcrum of all levels of education. Hence, any variable that triggers the academic performance of students ev...

The Preschool Imitation and Praxis Scale (PIPS) is a newly developed scale to measure action-level imitation in preschool children. The objective was to study the psychometric properties of the scale which includes Reliability (inter and intra) and the association between the PIPS test score and age. 495 children (12-59 months of age, mean age 37.0...

Divorce is referred to as the dissolution of marriage meaning canceling the legal duties and responsibilities of marriage and dissolving the bonds of matrimony between married persons. Since the time marriage became a civil contract and civil authorities asserted their power to decree divorce, there has been an increase and the menace becoming a so...

Hemolytic anemia is common in sickle cell disease (SCD), but the course and extent differ, depending on genetic, epigenetic, and environmental factors. In the malaria-endemic tropical environment, some vulnerable subjects would be infected and the impact of infection would vary. Therefore, this study was to find malaria incidence and the associated...

In the western world, transmission of hepatitis C occurs primarily through injecting drug use. Transmission of hepatitis C in injecting drug users is mainly associated with the sharing of contaminated syringes/needles, although evidence for risk of hepatitis C infection through sharing of other injecting paraphernalia is increasing. Due to the infl...