Browsing by Author "Opoku-Sarkodie, Richmond"

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Dynamics of an SIRWS model with waning of immunity and varying immune boosting period
(Journal of Biological Dynamics, 2022-07-29) Opoku-Sarkodie, Richmond; Bartha, Ferenc A.; Polner, Mónika; Röst, Gergely
SIRS models capture transmission dynamics of infectious diseases for which immunity is not lifelong. Extending these models by a W compartment for individuals with waning immunity, the boosting of the immune system upon repeated exposure may be incorporated. Previous analyses assumed identical waning rates from R to W and from W to S. This implicitly assumes equal length for the period of fullimmunityandofwanedimmunity.Werelaxthisrestriction,andallowan asymmetric partitioning of the total immune period. Stability switches of the endemic equilibrium are investigated with a combination of analytic and numerical tools. Then, continuation methods are applied to track bifurcations along the equilibrium branch. We find rich dynamics: Hopf bifurcations, endemic double bubbles, and regions of biostability. Our results highlight that the length of the period in which waning immunity can be boosted is a crucial parameter significantly influencing long term epidemiological dynamics.
Mathematical Model to Extrapolate the Population of Ghana: An Application of Newton‟s Divided Difference Formula
(Asia Pacific Journal of Multidisciplinary Research, 2015-05) Opoku-Sarkodie, Richmond; Acheampong, E.; Enu, Patrick; Bokoum, Amadu; Gardiner, F. A.; Manu, T. A.
This work presents the derivation of a mathematical model for extrapolating the population of Ghana using Newton’s divided difference formula. Newton’s divided difference formula was used because of the uneven time intervals at which the population census was conducted. A simulation was done using mathematical software to estimate the parameters in the derived model because the exact solution was quite difficult. The model was able to predict the population of Ghana with a residual percentage error within 10%. We will therefore recommend the usage of this model to be used for countries in which the population censuses were conducted at uneven time intervals as was the case with Ghana
Mathematical Model to Extrapolate the Population of Ghana: An Application of Newton‟s Divided Difference Formula
(Asia Pacific Journal of Multidisciplinary Research, 2015-05-02) Opoku-Sarkodie, Richmond; Acheampong, E.; Enu, Patrick; Bokoum, Amadu; Gardiner, F. A.; Manu, T. A.
This work presents the derivation of a mathematical model for extrapolating the population of Ghana using Newton’s divided difference formula. Newton’s divided difference formula was used because of the uneven time intervals at which the population census was conducted. A simulation was done using mathematical software to estimate the parameters in the derived model because the exact solution was quite difficult. The model was able to predict the population of Ghana with a residual percentage error within 10%. We will therefore recommend the usage of this model to be used for countries in which the population censuses were conducted at uneven time intervals as was the case with Ghana.
Mean Vector Analyses of the Voting Patterns of Ghanaians for Three Consecutive Periods: A Case Study of the Greater Accra Region
(Research Journal of Mathematics and Statistics, 2014-08-25) Opoku-Sarkodie, Richmond; Amponsah, S. Gyimah; Gardiner, F.; Manu, T.
The aim of this paper was to find out whether the outcome of future elections in the Greater Accra region could be predicted based on empirical data. The voting patterns of the presidential elections in Ghana deserve notice, not because of their political significance but because of the theoretical weight they carry. The shifts in electoral fortunes between the two main political parties in the country, especially in the greater Accra region provide a unique leverage for assessing theories of voting behavior. The paper uses statistical tools to examine the electoral performance of the four major political parties in Accra and the Hotelling’s T2 Statistic to test whether a prediction could be made to predict future outcomes of elections. Our results revealed that there was not enough statistical evidence to predict future outcomes of elections in the greater Accra district.
Vector-valued function application to projectile motion
(Asia Pacific Journal of Education, Arts and Sciences, 2015-04-14) Opoku-Sarkodie, Richmond; Acheampong, E.
This research work study the motion of a projectile without air resistance using vector-valued function. In this work, we combined the factors that affect the path of a trajectory to determine how a pilot can jump off from an aircraft into a river which is located at a known distance without falling on the ground in case there is a failure in the parachute. Based on our study of the problem statement, we established a theorem which states that at every maximum point (time) of a projectile (ignoring air resistance), the tangential component of acceleration is equal to zero and the normal component of acceleration is equal to gravity.