Department of Information Technology

Permanent URI for this collectionhttps://ir.mug.edu.gh/handle/123456789/137

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Optimum production scheduling for a beverage firm based in Accra
(Research Journal of Applied Sciences, Engineering and Technology, 2011-02-20) Amponsah, S.K; Ofosu, J.B.; Opoku-Sarkodie, R.
This study, which was conducted in Accra, Ghana, presents a production scheduling problem for a beverage firm based in Accra, all in an attempt to cut down manufacturing cost and increase efficiency. The creation of an optimum production schedule requires the modelling of the scheduling problem as a balanced transportation problem. An important result upon the implementation of the model is the allocation of the optimum level of production necessary to meet a given demand at a minimum cost.
A simple air deterministic mathematical model for determining oxygen and carbondioxide concentration in a sealed environment
(Research Journal of Mathematics and Statistics, 2014-08-25) Acheampong, E.; Gardiner, P.; Opoku-Sarkodie, R.; Manu, T.
This study presents a mathematical model that simulates oxygen and carbon-dioxide concentrations in a sealed environment without the actual measurement of the presence of these substances. Using Mathematical software for simulation, the model was tested using data (volume in cubic meters) of a sealed environment whiles varying the number of people in that environment. The results revealed that, the number of people in the sealed environment affected the concentrations of these substances in the air. Also the model revealed that there is a time (threshold) beyond which it will be unsafe to stay in such an environment.
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.
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.
Modelling the Queue at the Scan Station of Tema Port: An Application of Queuing Theory
(Asia Pacific Journal of Education, Arts and Sciences, 2015-07-03) Acheampong, E.; Opoku-Sarkodie, R.
The long hours spent in queues by imported consignment of goods waiting to be scanned causes congestion at the Tema Port. This study was conducted to find ways of reducing the time spent in queues by imported consignment of goods at the Tema Port. The main objective of this study was to minimize the time spent in queues by imported consignment of goods designated for the two scanners (Scanco and Nick-TC) for examination at the Tema Port. The study employed the technique of queuing theory for the analysis. We found that, the Scanco scanner had a faster service rate than the Nick-TC scanner when both were considered under the M/M/1 model where the two scanners served two independent queues. However, under the M/M/2 model where the two independent parallel scanners served one queue of designated consignments, the number of consignments (mean system size) in the queuing system reduced to 8.3984 per hour with an average waiting time of 0.5339 hours. Based on the findings, the following policy recommendations were made: The Ghana Ports and Harbours Authority, and the Government of Ghana must formulate policies to permit the two current existing scanners to serve only one single queue in order to ease the congestion caused by long hours of waiting in a queue.
Comparative analysis of comparison and non comparison based sorting algorithms
(International Journal of Computer Applications, 2020-10-28) Fenyi, Adolf; Fosu, Michael; Appiah, Bright
Sorting is one of the most important task in many computer applications. Efficiency becomes a big problem when the sorting involves a large amounts of data. There are a lot of sorting algorithms with different implementations. Some of them sort data by comparison while others don’t. The main aim of this thesis is to evaluate the comparison and noncomparison based algorithms in terms of execution time and memory consumption. Five main algorithms were selected for evaluation. Out of these five, three were comparison based algorithms (quick, bubble and merge) while the remaining two were non-comparison based (radix and counting). After conducting an experiment using array of different data sizes (ranging from 1000 to 35000), it was realized that the comparison based algorithms were less efficient than the noncomparison ones. Among the comparison algorithms, bubble sort had the highest time complexity due to the swapping nature of the algorithm. It never stops execution until the largest element is bubbled to the right of the array in every iteration. Despite this disadvantage, it was realized that it is memory efficient since it does not create new memory in every iteration. It relies on a single memory for the swapping array operation. The quick sort algorithm uses a reasonable amount of time to execute, but has a poor memory utilization due to the creation of numerous sub arrays to complete the sorting process. Among the comparison based algorithms, merge sort was far better than both quick and bubble. On the average, merge sort utilized 32.261 seconds to sort all the arrays used in the experiment while quick and bubble utilized 41.05 and 165.11 seconds respectively. The merge algorithm recorded an average memory consumption of 5.5MB for all the experiment while quick and bubble recorded 650.792MB and 4.54MB respectively. Even though the merge sort is better than both quick and bubble, it cannot be compared to the non-comparison based algorithms since they perform far better than the comparison based ones. When the two groups were evaluated against execution time, the comparison based algorithms recorded an average score of 476.757 seconds while the non-comparison obtained 17.849 seconds. With respect to the memory utilization, the non-comparison based algorithms obtained 27.12MB while the comparison ones obtained 1321.681MB. This clearly reveals the efficiency of the non-comparison based algorithms over the comparison ones in terms of execution time and memory utilization.
Sex differences in the experience of COVID-19 post-traumatic stress symptoms by adults in South Africa
(BMC Psychiatry, 2022-04-04) . Nzimande, Ntombifuthi P; Tantawi, Maha El; Zuñiga, Roberto Ariel Abeldaño; Opoku‑Sarkodie, Richmond; Brown, Brandon; Ezechi, Oliver C; . Uzochukwu, Benjamin S. C; Ellakany, Passent; Aly, Nourhan M.; Nguyen, Annie Lu; Folayan, Morenike Oluwatoyin
The COVID-19 pandemic has created multiple mental health challenges. Many residents in South Africa face pre-existing elevated levels of stress and the pandemic may have had varying impacts on sub-populations. The aims of this study were to determine: 1) the factors associated with post-traumatic stress symptoms (PTSS) and 2) sex differences in the factors associated with PTSS in adults residing in South Africa during the COVID-19 pandemic. Study participants aged 18 years and above, were recruited for this cross-sectional study through an online survey implemented from June 29, 2020 to December 31, 2020. The outcome variable was PTSS; explanatory variables were sex at birth, COVID-19 status, social isolation and access to emotional support. Confounders considered were age, education level completed and current work status. Logistic regressions were used to determine the association between the outcome and explanatory variables after adjusting for confounders. There were 489 respondents. Among all respondents, those who were older (AOR: 0.97; 95% CI: 0.95 – 0.99) and had access to emotional support from family and relatives (AOR: 0.27; 95% CI: 0.14 – 0.53) had significantly lower odds of PTSS. Respondents who felt socially isolated had higher odds of PTSS (AOR: 1.17; 95% CI: 1.08 – 1.27). Females had higher PTSS scores and higher odds of PTSS compared to males (AOR: 2.18; 95% CI: 1.41-3.39). Females (AOR: 0.27; 95% CI: 0.08 – 0.95) and males (AOR: 0.26; 95% CI: 0.11, 0.59) who had access to emotional support had significantly lower odds of PTSS than those who had no support. Females (AOR: 1.15; 95% CI: 1.04 -1.27) and males (AOR: 1.19; 95% CI: 0.11, 0.59) who felt socially isolated had higher odds of PTSS compared to those who did not feel socially isolated.Compared to males, females had higher scores and higher odds of reporting PTSS during the COVID19 pandemic. Access to emotional support ameliorated the odds of having PTSS for both sexes, while feeling socially isolated worsened the odds for both sexes
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.
Bifurcation analysis of waning-boosting epidemiological models with repeat infections and varying immunity periods
(Elsevier, 2024-04) Opoku-Sarkodie, R.; Bartha, F.A; Polner, M.; Röst, G.
We consider the SIRWJS epidemiological model that includes the waning and boosting of immunity via secondary infections. We carry out combined analytical and numerical investigations of the dynamics. The formulae describing the existence and stability of equilibria are derived. Combining this analysis with numerical continuation techniques, we construct global bifurcation diagrams with respect to several epidemiological parameters. The bifurcation analysis reveals a very rich structure of possible global dynamics. We show that backward bifurcation is possible at the critical value of the basic reproduction number, 0 = 1. Furthermore, we find stability switches and Hopf bifurcations from steady states forming multiple endemic bubbles, and saddle–node bifurcations of periodic orbits. Regions of bistability are also found, where either two stable steady states, or a stable steady state and a stable periodic orbit coexist. This work provides an insight to the rich and complicated infectious disease dynamics that can emerge from the waning and boosting of immunity.

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