It is a known fact that there are a particular set of people who are at higher risk of getting CO... more It is a known fact that there are a particular set of people who are at higher risk of getting COVID-19 infection. Typically, these high-risk individuals are recommended to take more preventive measures. The use of non-pharmaceutical interventions (NPIs) and the vaccine are playing a major role in the dynamics of the transmission of COVID-19. We propose a COVID-19 model with high-risk and low-risk susceptible individuals and their respective intervention strategies. We find two equilibrium solutions and we investigate the basic reproduction number. We also carry out the stability analysis of the equilibria. Further, this model is extended by considering the vaccination of some non-vaccinated individuals in the high-risk population. Sensitivity analyses and numerical simulations are carried out. From the results, we are able to obtain disease-free and endemic equilibrium solutions by solving the system of equations in the model and show their global stabilities using the Lyapunov fun...
Today, reverse osmosis (RO) is a critical technique in the production of fresh water all over the... more Today, reverse osmosis (RO) is a critical technique in the production of fresh water all over the world. As a result, downtimes due to repairing operations (after breakdowns, membrane blockage, pressure losses, etc.) or preventative maintenance (cleaning of membranes, component replacements, etc.) must be kept to a minimum in duration and frequency to guarantee optimum availability. Indeed, enhancing the availability (or dependability) of the RO plant as a whole system leads to a significant decrease in operating and maintenance expenses. We look at a recursive technique for reliability, availability, maintainability, and dependability in this study (RAMD. In addition, the efficacy of a RO unit, mean time to failure (MTTF), mean time to repair (MTTR), and dependability ratio were evaluated. The primary goal is economic optimization. For the method's validation, we utilized data from a RO unit that had a repair rate and a failure rate during a one-year period. It was demonstrated...
The present paper deals with profit modelling and comparison between two dissimilar systems under... more The present paper deals with profit modelling and comparison between two dissimilar systems under two types of failures based on Markovian Birth-Death process. Type I failure is minor in the sense that the work is in a reduced capacity whereas type II failure is major because it causes the entire system failure. Both systems consist of four subsystems arranged in series-parallel with three possible states: working with full capacity, reduced capacity and failed state. The systems are attended to by two repairmen in tandem. Through the transition diagrams, systems of differential difference equations are developed and solved recursively to obtain the steady-state availability, busy period of repair men, and profit function. Profit matrices for each subsystem have been developed for different combinations of failure and repair rates. Furthermore, we compare the profit for the two systems and find that system I is more profitable than system II.
2017 IEEE 3rd International Conference on Electro-Technology for National Development (NIGERCON), 2017
Matrix multiplication is presumably one of the most important techniques in many scientific appli... more Matrix multiplication is presumably one of the most important techniques in many scientific applications. Efficient implementation of this technique on the ubiquitous multi-cores is therefore critical to the performance of this broad range of applications. The execution time of sequential and parallel implementation of the algorithms were measured, analyzed and interpreted. The main aim of this research work is to compare the speedup obtainable from executing one-level recursion parallel Strassen's matrix multiplication algorithm on multi-core processors. The programs were written in C++/OpenMP. The result of the research work showed significant performance of the parallel programs of the Strassen's algorithm for large matrix size. It was also observed that Strassen's algorithm performs better for large matrix size while having the same performance as the Traditional algorithm for small matrices. The result suggested that with one step recursion, for both small and large...
International journal of information and management sciences, 2013
This paper deals with analysis of reliability characteristics of two unit active parallel system ... more This paper deals with analysis of reliability characteristics of two unit active parallel system connected to external supporting devices in cold standby for its operation. First order differential equations method is used to obtain the explicit expressions for mean time to system failure, steady-state availability, busy period of repairman and profit function. Some numerical experiments are conducted in order to illustrate the effects of failure and repair rates on reliability indices mentioned above.
Journal of Mathematical and Computational Science, May 15, 2013
Availability and profit of an industrial system are becoming an increasingly important issue. Whe... more Availability and profit of an industrial system are becoming an increasingly important issue. Where the availability of a system increases, the related profit will also increase. The objective of this paper is to present the effect of minor and major maintenance rates, and perfect repair rate on system availability and profit generated. We analyzed the system by using Kolmogorov’s forward equations method. Results have shown that perfect repair increases system availability and profit generated than minor and major maintenance. Through combine action of minor maintenance, major maintenance and perfect repair action the system availability and profit generated are improved. Models presented in this paper are important to engineers, maintenance managers, and plant management for proper maintenance analysis, decision and for safety of the system as a whole.
Many authors have studied maintenance or optimization models of deteriorating system without taki... more Many authors have studied maintenance or optimization models of deteriorating system without taking into consideration the kind or the degree of such deterioration on the system performance. Also little or no attention is found on the various stages of such deterioration and their effect on some measures of system effectiveness. In this study, we considered a system with three stages of deterioration: slow, medium or fast. Measures of system effectiveness like mean time to system failure (MTSF) and system availability were discussed. We analyzed the system using kolmogorov’s forward equations method and developed explicit expressions for mean time to system failure and steady state availability for the system. Some particular cases have also been discussed graphically to see the effect of deterioration rates on MTSF and system availability. The results have indicated that deterioration rates decrease the mean time to system failure and system availability.
The main objective of the present study is to analyze the availability of solar photovoltaic syst... more The main objective of the present study is to analyze the availability of solar photovoltaic system. The solar photovoltaic system in this paper is simple one consisting of four subsystems namely, solar panel subsystem, charge controller subsystem, batteries subsystem and inverter subsystem. Through the schematic diagram of state of the system, availability model is formulated and Chapmen - Kolmogorov differential equations are developed and solved using Gumbel Haugaard family Copula technique. The numerical values for availability, reliability, mean time to failure (MTTF), cost analysis as well as sensitivity analysis are presented. The effects of failure rates to various solar photovoltaic subsystems were developed.
Malaria is a deadly infectious disease, which is transmitted to humans via the bites of infected ... more Malaria is a deadly infectious disease, which is transmitted to humans via the bites of infected female mosquitoes. Antimalarial drug resistance has been identified as one of the characteristics of malaria that complicates control efforts. Typically, the use of insecticide-treated bed-nets (ITNs) and drug treatment are some of the recommended control strategies against malaria. Here, the use of ITNs, drug treatment, and their efficacies and evolution of antimalarial drug resistance are considered to be the major driving forces in the dynamics of malaria transmissions. We formulate a mathematical model of two-strain malaria to assess the impacts of ITNs, drug treatment, and their efficacies on the transmission dynamics of the disease in a human population. We propose a simple mosquito biting rate function that depends on both the proportion of ITN usage and its efficacy. We show that both disease-free and co-existence equilibrium points are globally-asymptotically stable where they e...
We modeled the impact of bed-net use and insecticide treated nets (ITNs), temperature, and treatm... more We modeled the impact of bed-net use and insecticide treated nets (ITNs), temperature, and treatment on malaria transmission dynamics using ordinary differential equations. To achieve this we formulated a simple model of mosquito biting rate that depends on temperature and usage of insecticides treated bed nets. We conducted global uncertainty and sensitivity analysis using Latin Hypercube Sampling (LHC) and Partial Rank Correlation Coefficient (PRCC) in order to find the most effective parameters that affect malaria transmission dynamics. We established the existence of the region where the model is epidemiologically feasible. We conducted the stability analysis of the disease-free equilibrium by the threshold parameter. We found the condition for the existence of the endemic equilibrium and provided necessary condition for its stability. Our results show that the peak of mosquitoes biting rate occurs at a range of temperature values not on a single value as previously reported in ...
It is a known fact that there are a particular set of people who are at higher risk of getting CO... more It is a known fact that there are a particular set of people who are at higher risk of getting COVID-19 infection. Typically, these high-risk individuals are recommended to take more preventive measures. The use of non-pharmaceutical interventions (NPIs) and the vaccine are playing a major role in the dynamics of the transmission of COVID-19. We propose a COVID-19 model with high-risk and low-risk susceptible individuals and their respective intervention strategies. We find two equilibrium solutions and we investigate the basic reproduction number. We also carry out the stability analysis of the equilibria. Further, this model is extended by considering the vaccination of some non-vaccinated individuals in the high-risk population. Sensitivity analyses and numerical simulations are carried out. From the results, we are able to obtain disease-free and endemic equilibrium solutions by solving the system of equations in the model and show their global stabilities using the Lyapunov fun...
Today, reverse osmosis (RO) is a critical technique in the production of fresh water all over the... more Today, reverse osmosis (RO) is a critical technique in the production of fresh water all over the world. As a result, downtimes due to repairing operations (after breakdowns, membrane blockage, pressure losses, etc.) or preventative maintenance (cleaning of membranes, component replacements, etc.) must be kept to a minimum in duration and frequency to guarantee optimum availability. Indeed, enhancing the availability (or dependability) of the RO plant as a whole system leads to a significant decrease in operating and maintenance expenses. We look at a recursive technique for reliability, availability, maintainability, and dependability in this study (RAMD. In addition, the efficacy of a RO unit, mean time to failure (MTTF), mean time to repair (MTTR), and dependability ratio were evaluated. The primary goal is economic optimization. For the method's validation, we utilized data from a RO unit that had a repair rate and a failure rate during a one-year period. It was demonstrated...
The present paper deals with profit modelling and comparison between two dissimilar systems under... more The present paper deals with profit modelling and comparison between two dissimilar systems under two types of failures based on Markovian Birth-Death process. Type I failure is minor in the sense that the work is in a reduced capacity whereas type II failure is major because it causes the entire system failure. Both systems consist of four subsystems arranged in series-parallel with three possible states: working with full capacity, reduced capacity and failed state. The systems are attended to by two repairmen in tandem. Through the transition diagrams, systems of differential difference equations are developed and solved recursively to obtain the steady-state availability, busy period of repair men, and profit function. Profit matrices for each subsystem have been developed for different combinations of failure and repair rates. Furthermore, we compare the profit for the two systems and find that system I is more profitable than system II.
2017 IEEE 3rd International Conference on Electro-Technology for National Development (NIGERCON), 2017
Matrix multiplication is presumably one of the most important techniques in many scientific appli... more Matrix multiplication is presumably one of the most important techniques in many scientific applications. Efficient implementation of this technique on the ubiquitous multi-cores is therefore critical to the performance of this broad range of applications. The execution time of sequential and parallel implementation of the algorithms were measured, analyzed and interpreted. The main aim of this research work is to compare the speedup obtainable from executing one-level recursion parallel Strassen's matrix multiplication algorithm on multi-core processors. The programs were written in C++/OpenMP. The result of the research work showed significant performance of the parallel programs of the Strassen's algorithm for large matrix size. It was also observed that Strassen's algorithm performs better for large matrix size while having the same performance as the Traditional algorithm for small matrices. The result suggested that with one step recursion, for both small and large...
International journal of information and management sciences, 2013
This paper deals with analysis of reliability characteristics of two unit active parallel system ... more This paper deals with analysis of reliability characteristics of two unit active parallel system connected to external supporting devices in cold standby for its operation. First order differential equations method is used to obtain the explicit expressions for mean time to system failure, steady-state availability, busy period of repairman and profit function. Some numerical experiments are conducted in order to illustrate the effects of failure and repair rates on reliability indices mentioned above.
Journal of Mathematical and Computational Science, May 15, 2013
Availability and profit of an industrial system are becoming an increasingly important issue. Whe... more Availability and profit of an industrial system are becoming an increasingly important issue. Where the availability of a system increases, the related profit will also increase. The objective of this paper is to present the effect of minor and major maintenance rates, and perfect repair rate on system availability and profit generated. We analyzed the system by using Kolmogorov’s forward equations method. Results have shown that perfect repair increases system availability and profit generated than minor and major maintenance. Through combine action of minor maintenance, major maintenance and perfect repair action the system availability and profit generated are improved. Models presented in this paper are important to engineers, maintenance managers, and plant management for proper maintenance analysis, decision and for safety of the system as a whole.
Many authors have studied maintenance or optimization models of deteriorating system without taki... more Many authors have studied maintenance or optimization models of deteriorating system without taking into consideration the kind or the degree of such deterioration on the system performance. Also little or no attention is found on the various stages of such deterioration and their effect on some measures of system effectiveness. In this study, we considered a system with three stages of deterioration: slow, medium or fast. Measures of system effectiveness like mean time to system failure (MTSF) and system availability were discussed. We analyzed the system using kolmogorov’s forward equations method and developed explicit expressions for mean time to system failure and steady state availability for the system. Some particular cases have also been discussed graphically to see the effect of deterioration rates on MTSF and system availability. The results have indicated that deterioration rates decrease the mean time to system failure and system availability.
The main objective of the present study is to analyze the availability of solar photovoltaic syst... more The main objective of the present study is to analyze the availability of solar photovoltaic system. The solar photovoltaic system in this paper is simple one consisting of four subsystems namely, solar panel subsystem, charge controller subsystem, batteries subsystem and inverter subsystem. Through the schematic diagram of state of the system, availability model is formulated and Chapmen - Kolmogorov differential equations are developed and solved using Gumbel Haugaard family Copula technique. The numerical values for availability, reliability, mean time to failure (MTTF), cost analysis as well as sensitivity analysis are presented. The effects of failure rates to various solar photovoltaic subsystems were developed.
Malaria is a deadly infectious disease, which is transmitted to humans via the bites of infected ... more Malaria is a deadly infectious disease, which is transmitted to humans via the bites of infected female mosquitoes. Antimalarial drug resistance has been identified as one of the characteristics of malaria that complicates control efforts. Typically, the use of insecticide-treated bed-nets (ITNs) and drug treatment are some of the recommended control strategies against malaria. Here, the use of ITNs, drug treatment, and their efficacies and evolution of antimalarial drug resistance are considered to be the major driving forces in the dynamics of malaria transmissions. We formulate a mathematical model of two-strain malaria to assess the impacts of ITNs, drug treatment, and their efficacies on the transmission dynamics of the disease in a human population. We propose a simple mosquito biting rate function that depends on both the proportion of ITN usage and its efficacy. We show that both disease-free and co-existence equilibrium points are globally-asymptotically stable where they e...
We modeled the impact of bed-net use and insecticide treated nets (ITNs), temperature, and treatm... more We modeled the impact of bed-net use and insecticide treated nets (ITNs), temperature, and treatment on malaria transmission dynamics using ordinary differential equations. To achieve this we formulated a simple model of mosquito biting rate that depends on temperature and usage of insecticides treated bed nets. We conducted global uncertainty and sensitivity analysis using Latin Hypercube Sampling (LHC) and Partial Rank Correlation Coefficient (PRCC) in order to find the most effective parameters that affect malaria transmission dynamics. We established the existence of the region where the model is epidemiologically feasible. We conducted the stability analysis of the disease-free equilibrium by the threshold parameter. We found the condition for the existence of the endemic equilibrium and provided necessary condition for its stability. Our results show that the peak of mosquitoes biting rate occurs at a range of temperature values not on a single value as previously reported in ...
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