A case for biogas as the viable substitute fuel in spark ignition engines
- Kukoyi, T. O., Muzenda. E., Mbohwa, Charles
- Authors: Kukoyi, T. O. , Muzenda. E. , Mbohwa, Charles
- Date: 2017
- Subjects: Biogas , Crude Oil , Fossil fuels
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/250381 , uj:26091 , Citation: Kukoyi, T.O., Muzenda. E. & Mbohwa, C. 2017. A case for biogas as the viable substitute fuel in spark ignition engines.
- Description: Abstract: Unstable prices, energy security, depleting reserves and their negative effect on the ecosystem have forced mankind to critically tackle it’s over dependence on fossil fuels. Fossil fuels are oil coal and natural gas which currently caters for over 80% of the world’s energy needs. Crude oil derivatives and coal have been extensively tapped and utilized to make living more comfortable and to drive different sectors that power the world’s economies. These have however come at an irreparable cost on human health and the environment. The transport sector, a major driver of development consumes the 2nd largest portion of our fossil energy reserves and has also been at the forefront of the creation of alternative fuels to mitigate various economic, political and environmental challenges associated with the refining and utilization of the conventional fuels in the sector which are petrol and diesel. The sector recently turned to natural gas as an efficient substitute particularly in the more popular passenger cars that utilize spark ignition engines. It performs excellently with lesser tail pipe emissions when compared with petrol which emits lesser harmful products than diesel. Though readily available, with well-developed infrastructure, its fossil nature makes it a finite resource hence the need for a viable renewable replacement fuel. Many alternative fuels have been developed to power the spark ignition engine as stricter emission standards are being created and the need for improved fuel economy with better system efficiency. This paper highlights the popular alternative fuels been utilized in spark ignition engines which are hydrogen, ethanol, liquefied petroleum gas and biogas looking at criteria such as performance, renewability, ease of integration into existing infrastructure and cost with the need to make a case for biogas as the right substitute for petrol in existing and future spark ignition engine applications.
- Full Text:
- Authors: Kukoyi, T. O. , Muzenda. E. , Mbohwa, Charles
- Date: 2017
- Subjects: Biogas , Crude Oil , Fossil fuels
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/250381 , uj:26091 , Citation: Kukoyi, T.O., Muzenda. E. & Mbohwa, C. 2017. A case for biogas as the viable substitute fuel in spark ignition engines.
- Description: Abstract: Unstable prices, energy security, depleting reserves and their negative effect on the ecosystem have forced mankind to critically tackle it’s over dependence on fossil fuels. Fossil fuels are oil coal and natural gas which currently caters for over 80% of the world’s energy needs. Crude oil derivatives and coal have been extensively tapped and utilized to make living more comfortable and to drive different sectors that power the world’s economies. These have however come at an irreparable cost on human health and the environment. The transport sector, a major driver of development consumes the 2nd largest portion of our fossil energy reserves and has also been at the forefront of the creation of alternative fuels to mitigate various economic, political and environmental challenges associated with the refining and utilization of the conventional fuels in the sector which are petrol and diesel. The sector recently turned to natural gas as an efficient substitute particularly in the more popular passenger cars that utilize spark ignition engines. It performs excellently with lesser tail pipe emissions when compared with petrol which emits lesser harmful products than diesel. Though readily available, with well-developed infrastructure, its fossil nature makes it a finite resource hence the need for a viable renewable replacement fuel. Many alternative fuels have been developed to power the spark ignition engine as stricter emission standards are being created and the need for improved fuel economy with better system efficiency. This paper highlights the popular alternative fuels been utilized in spark ignition engines which are hydrogen, ethanol, liquefied petroleum gas and biogas looking at criteria such as performance, renewability, ease of integration into existing infrastructure and cost with the need to make a case for biogas as the right substitute for petrol in existing and future spark ignition engine applications.
- Full Text:
A Cleaner Production (CP) Perspective for the Metal Industry Processes: Case Study
- Madanhire, Ignatio, Mbohwa, Charles
- Authors: Madanhire, Ignatio , Mbohwa, Charles
- Date: 2016
- Subjects: cleaner production , metal waste , metal fabrication
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/93083 , uj:20306 , Citation:Madanhire,I. & Mbohwa, C. A Cleaner Production (CP) Perspective for the Metal Industry Processes: Case Study.
- Description: Abstract: The study investigated the metal processing industry and established gaps in its application of cleaner production initiatives. Major processes were reviewed through use of material balance diagrams for typical operations. Upon which feasible CP options were generated to minimize waste and emissions from the metal industry. The specific framework guidelines for CP implementation were outlined for various metal industry sector processes.
- Full Text:
- Authors: Madanhire, Ignatio , Mbohwa, Charles
- Date: 2016
- Subjects: cleaner production , metal waste , metal fabrication
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/93083 , uj:20306 , Citation:Madanhire,I. & Mbohwa, C. A Cleaner Production (CP) Perspective for the Metal Industry Processes: Case Study.
- Description: Abstract: The study investigated the metal processing industry and established gaps in its application of cleaner production initiatives. Major processes were reviewed through use of material balance diagrams for typical operations. Upon which feasible CP options were generated to minimize waste and emissions from the metal industry. The specific framework guidelines for CP implementation were outlined for various metal industry sector processes.
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A dynamic simulation of a lean and agile manufacturing system
- Mutingi, M., Mbohwa, Charles, Mhlanga, S.
- Authors: Mutingi, M. , Mbohwa, Charles , Mhlanga, S.
- Date: 2013
- Subjects: Agile manufacturing , Lean thinking , Manufacturing systems
- Type: Article
- Identifier: uj:4947 , http://hdl.handle.net/10210/13047
- Description: The integration of just-in-time and lean principles in agile manufacturing plays an important role in enhancing the operational performance of manufacturing systems. In this paper, we address this issue by (i) building a set of performance criteria for a typical manufacturing system, (ii) developing a system dynamics model for the system, and (iii) performing experimental “what-if” simulation analyses. Using a system dynamics simulation methodology, the impact of the application of lean and just-in-time policies on a traditional inventory-focused manufacturing system is investigated. System dynamics modelling is used to capture the dynamic causal linkages between different components of the manufacturing system. Different scenarios are generated in order to investigate the dynamics of the system under assumed demand scenarios. The results of the simulation study reveal that manufacturing systems can benefit from the introduction of lean and just-in-time principles, depending on the extent to which the necessary structural changes are implemented. The paper concludes by providing useful managerial insights for effective implementation of lean and agile manufacturing concepts.
- Full Text:
- Authors: Mutingi, M. , Mbohwa, Charles , Mhlanga, S.
- Date: 2013
- Subjects: Agile manufacturing , Lean thinking , Manufacturing systems
- Type: Article
- Identifier: uj:4947 , http://hdl.handle.net/10210/13047
- Description: The integration of just-in-time and lean principles in agile manufacturing plays an important role in enhancing the operational performance of manufacturing systems. In this paper, we address this issue by (i) building a set of performance criteria for a typical manufacturing system, (ii) developing a system dynamics model for the system, and (iii) performing experimental “what-if” simulation analyses. Using a system dynamics simulation methodology, the impact of the application of lean and just-in-time policies on a traditional inventory-focused manufacturing system is investigated. System dynamics modelling is used to capture the dynamic causal linkages between different components of the manufacturing system. Different scenarios are generated in order to investigate the dynamics of the system under assumed demand scenarios. The results of the simulation study reveal that manufacturing systems can benefit from the introduction of lean and just-in-time principles, depending on the extent to which the necessary structural changes are implemented. The paper concludes by providing useful managerial insights for effective implementation of lean and agile manufacturing concepts.
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A framework for analysis and evaluation of renewable energy policies
- Mutingi, Michael, Mbohwa, Charles
- Authors: Mutingi, Michael , Mbohwa, Charles
- Date: 2014
- Subjects: Energy planning , Renewable energy policies
- Type: Article
- Identifier: uj:4921 , http://hdl.handle.net/10210/13021
- Description: The formulation and evaluation of renewable energy policies is a burning subject matter all over the globe. Policy makers seek to cautiously perceive information from the renewable energy market place so as to determine the dynamic factors, variables and policy parameters that influence the design of renewable energy policies. The perceived information is often imprecise or fuzzy, which makes policy formulation difficult. This paper presents a framework for evaluating renewable energy policies based on a fuzzy system dynamics (FSD) paradigm. First, we describe the renewable energy policy problem, with a case study example. Second, we present a framework for FSD modeling. Third, we propose a high-level causal loop analysis to capture the complex dynamic interactions among various energy demand and supply factors, from a fuzzy system dynamics perspective. Fourth, and finally, we propose an FSD model for renewable energy policy formulation and evaluation.
- Full Text:
- Authors: Mutingi, Michael , Mbohwa, Charles
- Date: 2014
- Subjects: Energy planning , Renewable energy policies
- Type: Article
- Identifier: uj:4921 , http://hdl.handle.net/10210/13021
- Description: The formulation and evaluation of renewable energy policies is a burning subject matter all over the globe. Policy makers seek to cautiously perceive information from the renewable energy market place so as to determine the dynamic factors, variables and policy parameters that influence the design of renewable energy policies. The perceived information is often imprecise or fuzzy, which makes policy formulation difficult. This paper presents a framework for evaluating renewable energy policies based on a fuzzy system dynamics (FSD) paradigm. First, we describe the renewable energy policy problem, with a case study example. Second, we present a framework for FSD modeling. Third, we propose a high-level causal loop analysis to capture the complex dynamic interactions among various energy demand and supply factors, from a fuzzy system dynamics perspective. Fourth, and finally, we propose an FSD model for renewable energy policy formulation and evaluation.
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A framework for developing performance measurement systems for “green” supply chain management strategies
- Mutingi, M., Mhlanga, S, Mbohwa, Charles, Mapfaira, H
- Authors: Mutingi, M. , Mhlanga, S , Mbohwa, Charles , Mapfaira, H
- Date: 2013
- Subjects: Performance measurement , Performance management systems , Supply chain management
- Type: Article
- Identifier: uj:6167 , ISBN 978-0-7972-1405-7 , http://hdl.handle.net/10210/13774
- Description: As environmental issues are continually and rapidly emerging as one of the most crucial topics in strategic manufacturing decision making, the formulation of “green” performance management systems is very important. This research seeks to introduce and explore green performance measurement frameworks that exist in various real-world case studies that are found in literature. The study yielded a set of four taxonomic performance measurement systems that are applicable in specific contexts of manufacturing supply chain strategies. Moreover, specific green performance metrics are provided in respect of the identified green manufacturing strategies. Implications of the application of each performance management system on existing manufacturing policies are evaluated, giving practical managerial insights. The study forms an essential framework for the decision maker to rapidly develop a suitable performance system in a green manufacturing environment, within a reasonable time frame.
- Full Text:
- Authors: Mutingi, M. , Mhlanga, S , Mbohwa, Charles , Mapfaira, H
- Date: 2013
- Subjects: Performance measurement , Performance management systems , Supply chain management
- Type: Article
- Identifier: uj:6167 , ISBN 978-0-7972-1405-7 , http://hdl.handle.net/10210/13774
- Description: As environmental issues are continually and rapidly emerging as one of the most crucial topics in strategic manufacturing decision making, the formulation of “green” performance management systems is very important. This research seeks to introduce and explore green performance measurement frameworks that exist in various real-world case studies that are found in literature. The study yielded a set of four taxonomic performance measurement systems that are applicable in specific contexts of manufacturing supply chain strategies. Moreover, specific green performance metrics are provided in respect of the identified green manufacturing strategies. Implications of the application of each performance management system on existing manufacturing policies are evaluated, giving practical managerial insights. The study forms an essential framework for the decision maker to rapidly develop a suitable performance system in a green manufacturing environment, within a reasonable time frame.
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A framework for sharing tacit knowledge within SMMEs : a South African Study
- Seseni, Lawrance, Mbohwa, Charles
- Authors: Seseni, Lawrance , Mbohwa, Charles
- Date: 2016
- Subjects: Knowledge management , SMMEs , Tacit knowledge
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/213980 , uj:21221 , Seseni, L & Mbohwa, C. 2016. A framework for sharing tacit knowledge within SMMEs : a South African Study.
- Description: Abstract: This study aims to develop a framework for effectively sharing knowledge within SMMEs that are situated in Johannesburg, South Africa. This is a qualitative approach. It was discussed that tacit knowledge is an intangible resource and intellectual capital that is not easily transferred to other people because some employees of the employees are not eager to share their knowledge. This can be as desire of having an upper hand over their colleagues. However, this paper discovered that in order for effective knowledge sharing to take place there must be a culture of sharing within the organization, those who are sharing and receiving knowledge must be given sufficient time so that sharing may be effective, management must support their subordinates by means of giving them the resources that they may need, there must be effective teamwork, employees must be committed and motivated, effective communication and the must be trust between the employees themselves and employees and their employers. Further research should be done on the correlations between the framework’s independent variable and the dependent variables of sharing knowledge within SMMEs.
- Full Text:
- Authors: Seseni, Lawrance , Mbohwa, Charles
- Date: 2016
- Subjects: Knowledge management , SMMEs , Tacit knowledge
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/213980 , uj:21221 , Seseni, L & Mbohwa, C. 2016. A framework for sharing tacit knowledge within SMMEs : a South African Study.
- Description: Abstract: This study aims to develop a framework for effectively sharing knowledge within SMMEs that are situated in Johannesburg, South Africa. This is a qualitative approach. It was discussed that tacit knowledge is an intangible resource and intellectual capital that is not easily transferred to other people because some employees of the employees are not eager to share their knowledge. This can be as desire of having an upper hand over their colleagues. However, this paper discovered that in order for effective knowledge sharing to take place there must be a culture of sharing within the organization, those who are sharing and receiving knowledge must be given sufficient time so that sharing may be effective, management must support their subordinates by means of giving them the resources that they may need, there must be effective teamwork, employees must be committed and motivated, effective communication and the must be trust between the employees themselves and employees and their employers. Further research should be done on the correlations between the framework’s independent variable and the dependent variables of sharing knowledge within SMMEs.
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A fuzzy genetic algorithm for healthcare staff scheduling
- Mutingi, Michael, Mbohwa, Charles
- Authors: Mutingi, Michael , Mbohwa, Charles
- Date: 2013
- Subjects: Healthcare staff scheduling , Fuzzy-based genetic algorithm , Fuzzy sets
- Type: Article
- Identifier: uj:6172 , ISBN 978-93-82242-26-0 , http://hdl.handle.net/10210/13779
- Description: In the presence of multiple conflicting objectives and constraints, healthcare staff scheduling is complex. This research presents a fuzzy-based genetic algorithm (FGA) for handling multiple conflicting objectives and constraints common in healthcare manpower scheduling problems. Fuzzy set theory is used for genetic evaluations of alternative staff schedules by representing the fitness of each alternative solution as a fuzzy membership functions. The proposed FGA framework is designed to incorporate the often imprecise decision maker’s preferences and choices in terms of weights. The framework is also designed to provide a population of alternative solutions for the decision maker, rather than prescribe a single decision. It is anticipated that the FGA procedure forms a useful decision support tool for healthcare staff scheduling in a fuzzy environment with multiple conflicting objectives and constraints.
- Full Text:
- Authors: Mutingi, Michael , Mbohwa, Charles
- Date: 2013
- Subjects: Healthcare staff scheduling , Fuzzy-based genetic algorithm , Fuzzy sets
- Type: Article
- Identifier: uj:6172 , ISBN 978-93-82242-26-0 , http://hdl.handle.net/10210/13779
- Description: In the presence of multiple conflicting objectives and constraints, healthcare staff scheduling is complex. This research presents a fuzzy-based genetic algorithm (FGA) for handling multiple conflicting objectives and constraints common in healthcare manpower scheduling problems. Fuzzy set theory is used for genetic evaluations of alternative staff schedules by representing the fitness of each alternative solution as a fuzzy membership functions. The proposed FGA framework is designed to incorporate the often imprecise decision maker’s preferences and choices in terms of weights. The framework is also designed to provide a population of alternative solutions for the decision maker, rather than prescribe a single decision. It is anticipated that the FGA procedure forms a useful decision support tool for healthcare staff scheduling in a fuzzy environment with multiple conflicting objectives and constraints.
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A fuzzy grouping genetic algorithm for care assignment task
- Mutingi, Michael, Mbohwa, Charles
- Authors: Mutingi, Michael , Mbohwa, Charles
- Date: 2014
- Subjects: Care tasks , Task assignment , Fuzzy grouping genetic algorithm , Fuzzy theory
- Type: Article
- Identifier: uj:4935 , ISSN 2078-0966 , http://hdl.handle.net/10210/13035
- Description: The assignment of care tasks to nurses is often done manually in most hospitals. A high quality care task schedule is crucial for efficient and effective execution of nursing care duties. High quality schedules seek to satisfy patient preferences over time window for the care, schedule fairness among nurses, and management goals regarding care activity completion times and labor costs. This paper suggests a grouping genetic approach to care task scheduling in a hospital setting. By taking advantage of the group structure of the problem, the algorithm uses fuzzy evaluation techniques, permuting tasks across candidate nurse schedules and within each nurse schedule. Results of the computational experiments show that the proposed approach is effective.
- Full Text:
- Authors: Mutingi, Michael , Mbohwa, Charles
- Date: 2014
- Subjects: Care tasks , Task assignment , Fuzzy grouping genetic algorithm , Fuzzy theory
- Type: Article
- Identifier: uj:4935 , ISSN 2078-0966 , http://hdl.handle.net/10210/13035
- Description: The assignment of care tasks to nurses is often done manually in most hospitals. A high quality care task schedule is crucial for efficient and effective execution of nursing care duties. High quality schedules seek to satisfy patient preferences over time window for the care, schedule fairness among nurses, and management goals regarding care activity completion times and labor costs. This paper suggests a grouping genetic approach to care task scheduling in a hospital setting. By taking advantage of the group structure of the problem, the algorithm uses fuzzy evaluation techniques, permuting tasks across candidate nurse schedules and within each nurse schedule. Results of the computational experiments show that the proposed approach is effective.
- Full Text:
A fuzzy-based particle swarm optimization algorithm for nurse scheduling
- Mutingi, Michael, Mbohwa, Charles
- Authors: Mutingi, Michael , Mbohwa, Charles
- Date: 2014
- Subjects: Nurse scheduling , Nurse rostering , Personnel scheduling , Particle swarm optimization
- Type: Article
- Identifier: uj:4926 , ISSN 2078-0966 , http://hdl.handle.net/10210/13026
- Description: The nurse scheduling problem (NSP) has a great impact on the quality and efficiency of health care operations. Healthcare Operations Analysts have to assign daily shifts to nurses over the planning horizon, so that operations costs are minimized, health care quality is improved, and the nursing staff is satisfied. Due to conflicting objectives and a myriad of restrictions imposed by labor laws, company requirements, and other legislative laws, the NSP is a hard problem. In this paper we present a particle swarm optimization-based algorithm that relies on a heuristic mechanism that incorporates hard constraints to improve the computational efficiency of the algorithm. Further, we incorporate soft constraints into objective function evaluation to guide the algorithm. Results from illustrative examples show that the algorithm is effective and efficient, even over large scale problems.
- Full Text:
- Authors: Mutingi, Michael , Mbohwa, Charles
- Date: 2014
- Subjects: Nurse scheduling , Nurse rostering , Personnel scheduling , Particle swarm optimization
- Type: Article
- Identifier: uj:4926 , ISSN 2078-0966 , http://hdl.handle.net/10210/13026
- Description: The nurse scheduling problem (NSP) has a great impact on the quality and efficiency of health care operations. Healthcare Operations Analysts have to assign daily shifts to nurses over the planning horizon, so that operations costs are minimized, health care quality is improved, and the nursing staff is satisfied. Due to conflicting objectives and a myriad of restrictions imposed by labor laws, company requirements, and other legislative laws, the NSP is a hard problem. In this paper we present a particle swarm optimization-based algorithm that relies on a heuristic mechanism that incorporates hard constraints to improve the computational efficiency of the algorithm. Further, we incorporate soft constraints into objective function evaluation to guide the algorithm. Results from illustrative examples show that the algorithm is effective and efficient, even over large scale problems.
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A group genetic algorithm for the fleet size and mix vehicle routing problem
- Mutingi, M., Mbohwa, Charles
- Authors: Mutingi, M. , Mbohwa, Charles
- Date: 2012
- Subjects: Logistics , Vehicle routing , Genetic algorithms , Vehicle fleets - Management
- Type: Article
- Identifier: uj:5181 , http://hdl.handle.net/10210/14423
- Description: In logistics management, the use of vehicles to distribute products from suppliers to customers is a major operational activity. Optimizing the routing of vehicles is crucial for providing cost-effective services to customers. This research addresses the fleet size and mix vehicle routing problem (FSMVRP), where the heterogeneous fleet and its size are to be determined. A group genetic algorithm (GGA) approach, with unique genetic operators, is designed and implemented on a number of existing benchmark problems. GGA demonstrates competitive performance in terms of cost and computation time when compared to other heuristics.
- Full Text:
- Authors: Mutingi, M. , Mbohwa, Charles
- Date: 2012
- Subjects: Logistics , Vehicle routing , Genetic algorithms , Vehicle fleets - Management
- Type: Article
- Identifier: uj:5181 , http://hdl.handle.net/10210/14423
- Description: In logistics management, the use of vehicles to distribute products from suppliers to customers is a major operational activity. Optimizing the routing of vehicles is crucial for providing cost-effective services to customers. This research addresses the fleet size and mix vehicle routing problem (FSMVRP), where the heterogeneous fleet and its size are to be determined. A group genetic algorithm (GGA) approach, with unique genetic operators, is designed and implemented on a number of existing benchmark problems. GGA demonstrates competitive performance in terms of cost and computation time when compared to other heuristics.
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A home healthcare multi-agent system in a multi-objective environment
- Mutingi, M., Mbohwa, Charles
- Authors: Mutingi, M. , Mbohwa, Charles
- Date: 2013
- Subjects: Home healthcare , Multiagent systems
- Type: Article
- Identifier: http://ujcontent.uj.ac.za8080/10210/380551 , uj:4974 , http://hdl.handle.net/10210/13075
- Description: Decision making in home care service is complex due to the need to satisfice multi-objective goals such as maximizing customer service quality, minimizing service cost, and maximizing employee satisfaction. With the increasing world-wide need for efficient and effective home healthcare, the increasing elderly population, and the increasing pressure from governments and other stakeholders in various societies, the development of effective novel approaches for home care decisions is imperative. In this paper, we present a multi-agent architecture that facilitates decision making characterised with multiple objectives. The approach integrates the capabilities of a multi-agent system and Web services so as to facilitate effective decisions for home healthcare services. The aim is to provide a multi-agent system based on genetic algorithm, where decisions are based on intelligent agents that provide intelligent alternative decisions in a multiple-objective environment.
- Full Text:
- Authors: Mutingi, M. , Mbohwa, Charles
- Date: 2013
- Subjects: Home healthcare , Multiagent systems
- Type: Article
- Identifier: http://ujcontent.uj.ac.za8080/10210/380551 , uj:4974 , http://hdl.handle.net/10210/13075
- Description: Decision making in home care service is complex due to the need to satisfice multi-objective goals such as maximizing customer service quality, minimizing service cost, and maximizing employee satisfaction. With the increasing world-wide need for efficient and effective home healthcare, the increasing elderly population, and the increasing pressure from governments and other stakeholders in various societies, the development of effective novel approaches for home care decisions is imperative. In this paper, we present a multi-agent architecture that facilitates decision making characterised with multiple objectives. The approach integrates the capabilities of a multi-agent system and Web services so as to facilitate effective decisions for home healthcare services. The aim is to provide a multi-agent system based on genetic algorithm, where decisions are based on intelligent agents that provide intelligent alternative decisions in a multiple-objective environment.
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A multi-criteria approach for nurse scheduling : fuzzy simulated metamorphosis algorithm approach
- Mutingi, Michael, Mbohwa, Charles
- Authors: Mutingi, Michael , Mbohwa, Charles
- Date: 2015-03-03
- Subjects: Healthcare staff scheduling , Nurse rostering , Fuzzy sets
- Type: Article
- Identifier: uj:5221 , http://hdl.handle.net/10210/14507
- Description: Motivated by the biological metamorphosis process and the need to solve multi-objective optimization problems with conflicting and fuzzy goals and constraints, this paper proposes a simulated metamorphosis algorithm, based on the concepts of biological evolution in insects, such as moths, butterflies, and beetles. By mimicking the hormone controlled evolution process the algorithm works on a single candidate solution, going through initialization, iterative growth loop, and finally maturation loop. The method is a practical way to optimizing multi-objective problems with fuzzy conflicting goals and constraints. The approach is applied to the nurse scheduling problem. Equipped with the facility to incorporate the user’s choices and wishes, the algorithm offers an interactive approach that can accommodate the decision maker’s expert intuition and experience, which is otherwise impossible with other optimization algorithms. By using hormonal guidance and unique operators, the algorithm works on a single candidate solution, and efficiently evolves it to a near-optimal solution. Computational experiments show that the algorithm is competitive.
- Full Text:
- Authors: Mutingi, Michael , Mbohwa, Charles
- Date: 2015-03-03
- Subjects: Healthcare staff scheduling , Nurse rostering , Fuzzy sets
- Type: Article
- Identifier: uj:5221 , http://hdl.handle.net/10210/14507
- Description: Motivated by the biological metamorphosis process and the need to solve multi-objective optimization problems with conflicting and fuzzy goals and constraints, this paper proposes a simulated metamorphosis algorithm, based on the concepts of biological evolution in insects, such as moths, butterflies, and beetles. By mimicking the hormone controlled evolution process the algorithm works on a single candidate solution, going through initialization, iterative growth loop, and finally maturation loop. The method is a practical way to optimizing multi-objective problems with fuzzy conflicting goals and constraints. The approach is applied to the nurse scheduling problem. Equipped with the facility to incorporate the user’s choices and wishes, the algorithm offers an interactive approach that can accommodate the decision maker’s expert intuition and experience, which is otherwise impossible with other optimization algorithms. By using hormonal guidance and unique operators, the algorithm works on a single candidate solution, and efficiently evolves it to a near-optimal solution. Computational experiments show that the algorithm is competitive.
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A new product development framework for a timber processing company
- Nyemba, Wilson R., Mushiri, Tawanda, Mbohwa, Charles, Shoniwa, Kuda J.
- Authors: Nyemba, Wilson R. , Mushiri, Tawanda , Mbohwa, Charles , Shoniwa, Kuda J.
- Date: 2016
- Subjects: New product development , Quality function deployment , Stage-Gate modelling.
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/91902 , uj:20160 , Citation: Nyemba, W.R. et al. 2016. A new product development framework for a timber processing company.
- Description: Abstract: Customer perceptions of products continuously change over time. Marketing specialists are generally tasked with the responsibility of rebranding and product changes. However this is normally technology driven, with inputs from engineering designers and manufacturers providing the designs and feasibilities for either modifying existing designs or developing new ones. An opportunity arose at a timber processing company where a variety of products such as domestic and commercial furniture are manufactured. This paper reports on the development of a framework for formulating new products using the wide array of hard and soft wood that the company processes. A work study was conducted, focusing on the company’s production capacity, sales history of their twenty-three products, market trends and interviews with current customers. The research set out to develop innovative and new product platforms (product families) that are unique and represent the company while satisfying customer needs and requirements. A stage-gate model of the New Product Development (NPD) framework was formulated. Coupled with Quality Function Deployment (QFD) and weighted objectives, the use of the stage-gate model was demonstrated in the development of a four wheeler coffee table into a prototype. Implementation of the stage-gate model and further research into the four-wheeler coffee table were recommended as well as other areas related to NPD.
- Full Text:
- Authors: Nyemba, Wilson R. , Mushiri, Tawanda , Mbohwa, Charles , Shoniwa, Kuda J.
- Date: 2016
- Subjects: New product development , Quality function deployment , Stage-Gate modelling.
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/91902 , uj:20160 , Citation: Nyemba, W.R. et al. 2016. A new product development framework for a timber processing company.
- Description: Abstract: Customer perceptions of products continuously change over time. Marketing specialists are generally tasked with the responsibility of rebranding and product changes. However this is normally technology driven, with inputs from engineering designers and manufacturers providing the designs and feasibilities for either modifying existing designs or developing new ones. An opportunity arose at a timber processing company where a variety of products such as domestic and commercial furniture are manufactured. This paper reports on the development of a framework for formulating new products using the wide array of hard and soft wood that the company processes. A work study was conducted, focusing on the company’s production capacity, sales history of their twenty-three products, market trends and interviews with current customers. The research set out to develop innovative and new product platforms (product families) that are unique and represent the company while satisfying customer needs and requirements. A stage-gate model of the New Product Development (NPD) framework was formulated. Coupled with Quality Function Deployment (QFD) and weighted objectives, the use of the stage-gate model was demonstrated in the development of a four wheeler coffee table into a prototype. Implementation of the stage-gate model and further research into the four-wheeler coffee table were recommended as well as other areas related to NPD.
- Full Text:
A review of municipal solid waste data for Harare, Zimbabwe
- Nhubu, T., Muzenda, E., Mbohwa, Charles, Patel, B.
- Authors: Nhubu, T. , Muzenda, E. , Mbohwa, Charles , Patel, B.
- Date: 2019
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/400914 , uj:33482 , Citation: Nhubu, T. et al. 2019. A review of municipal solid waste data for Harare, Zimbabwe.
- Description: Abstract: Municipal solid waste (MSW) data sources in Harare metropolitan province show significantly varying data with regards to generation and composition. The sources of variations include data lumping; exclusion of MSW managed outside the formal system and remain uncol-lected, lack of a clear definition of what constitutes MSW within the Zimbabwean context as well as temporal variations. It is therefore important for waste generation and characterisation studies to be undertaken building upon the already existing datasets to ensure the accuracy and reliability needed for data credibility for use in MSW management planning.
- Full Text:
- Authors: Nhubu, T. , Muzenda, E. , Mbohwa, Charles , Patel, B.
- Date: 2019
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/400914 , uj:33482 , Citation: Nhubu, T. et al. 2019. A review of municipal solid waste data for Harare, Zimbabwe.
- Description: Abstract: Municipal solid waste (MSW) data sources in Harare metropolitan province show significantly varying data with regards to generation and composition. The sources of variations include data lumping; exclusion of MSW managed outside the formal system and remain uncol-lected, lack of a clear definition of what constitutes MSW within the Zimbabwean context as well as temporal variations. It is therefore important for waste generation and characterisation studies to be undertaken building upon the already existing datasets to ensure the accuracy and reliability needed for data credibility for use in MSW management planning.
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A review on factors affecting municipal solid waste generation
- Masebinu, S. O., Akinlabi, Esther Titilayo, Muzenda, E., Aboyade, A. O., Mbohwa, Charles, Manyuchi, M., Naidoo, P.
- Authors: Masebinu, S. O. , Akinlabi, Esther Titilayo , Muzenda, E. , Aboyade, A. O. , Mbohwa, Charles , Manyuchi, M. , Naidoo, P.
- Date: 2017
- Subjects: Municipal solid waste , Waste quantity , Waste generation factors
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/250378 , uj:26089 , Citation: Masebinu, S.O. et al. 2017. A review on factors affecting municipal solid waste generation. 2nd International Engineering Conference (IEC 2017) Federal University of Technology, Minna, Nigeria.
- Description: Abstract: Municipal solid waste (MSW) management is not a one-off planning, it is a dynamic evolution and planning has to cater for it. The quantity of MSW generated and composition form the basis for planning and management of MSW. However, for an effective MSW reduction policy to be implemented, generated quantity of MSW is not sufficient alone for policy implementation but more of the variables affecting the generation rate and composition are critical. Without an in-depth understanding of these variables, waste reduction policies may be ineffective and unsuccessful. In this study, we reviewed the impact of these factors on MSW. A case of the City of Johannesburg (CoJ) was studied. Population and gross domestic product (GDP) are the two compelling factors affecting MSW generation. The waste generation per capita is influenced by income level. High income group generate on average 1.91 kg/capita/day, middle income group generates 1.01 kg/capita/day and low income group 0.92 kg/capita/day. This put the CoJ total waste generated at an average of 1.83 million ton/year.
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- Authors: Masebinu, S. O. , Akinlabi, Esther Titilayo , Muzenda, E. , Aboyade, A. O. , Mbohwa, Charles , Manyuchi, M. , Naidoo, P.
- Date: 2017
- Subjects: Municipal solid waste , Waste quantity , Waste generation factors
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/250378 , uj:26089 , Citation: Masebinu, S.O. et al. 2017. A review on factors affecting municipal solid waste generation. 2nd International Engineering Conference (IEC 2017) Federal University of Technology, Minna, Nigeria.
- Description: Abstract: Municipal solid waste (MSW) management is not a one-off planning, it is a dynamic evolution and planning has to cater for it. The quantity of MSW generated and composition form the basis for planning and management of MSW. However, for an effective MSW reduction policy to be implemented, generated quantity of MSW is not sufficient alone for policy implementation but more of the variables affecting the generation rate and composition are critical. Without an in-depth understanding of these variables, waste reduction policies may be ineffective and unsuccessful. In this study, we reviewed the impact of these factors on MSW. A case of the City of Johannesburg (CoJ) was studied. Population and gross domestic product (GDP) are the two compelling factors affecting MSW generation. The waste generation per capita is influenced by income level. High income group generate on average 1.91 kg/capita/day, middle income group generates 1.01 kg/capita/day and low income group 0.92 kg/capita/day. This put the CoJ total waste generated at an average of 1.83 million ton/year.
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A review on standards, practices and future prospects of project management in a South African context
- Mukwakungu, Sambil Charles, Mabasa, Matimba Davis, Mbohwa, Charles
- Authors: Mukwakungu, Sambil Charles , Mabasa, Matimba Davis , Mbohwa, Charles
- Date: 2018
- Subjects: Project management practices and standard , Project management competency , Competitive advantage
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/273815 , uj:29181 , Citation: Mukwakungu, S.C., Mabasa, M.D. & Mbohwa, C. 2018. A review on standards, practices and future prospects of project management in a South African context.
- Description: Abstract: This article investigates the state of affairs of Project Management as one key discipline that is beneficial to both private and public organizations in the country. A gap analysis was conducted in reviewing the literature of published articles that are relevant to the project management’s practices and standards, to gain insight with regard to what has been covered by academics in the field of Project Management. It was established that various authors consider project management as a tool that is not limited to projects but applicable strategically by different organizations in different fields, despite their uniqueness. Therefore strengthening the ability of project management practitioners through project management programs is a cornerstone in the country’s economic growth and stability.
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- Authors: Mukwakungu, Sambil Charles , Mabasa, Matimba Davis , Mbohwa, Charles
- Date: 2018
- Subjects: Project management practices and standard , Project management competency , Competitive advantage
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/273815 , uj:29181 , Citation: Mukwakungu, S.C., Mabasa, M.D. & Mbohwa, C. 2018. A review on standards, practices and future prospects of project management in a South African context.
- Description: Abstract: This article investigates the state of affairs of Project Management as one key discipline that is beneficial to both private and public organizations in the country. A gap analysis was conducted in reviewing the literature of published articles that are relevant to the project management’s practices and standards, to gain insight with regard to what has been covered by academics in the field of Project Management. It was established that various authors consider project management as a tool that is not limited to projects but applicable strategically by different organizations in different fields, despite their uniqueness. Therefore strengthening the ability of project management practitioners through project management programs is a cornerstone in the country’s economic growth and stability.
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A review on the impact of leadership in healthcare : South African context
- Mukwakungu, Sambil Charles, Mabasa, Matimba Davis, Mbohwa, Charles
- Authors: Mukwakungu, Sambil Charles , Mabasa, Matimba Davis , Mbohwa, Charles
- Date: 2018
- Subjects: Leadership , Health Care Practitioners , Health Care System
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/273141 , uj:29093 , Citation: Mukwakungu, S.C., Mabasa, M.D. & Mbohwa, C. 2018. A review on the impact of leadership in healthcare : South African context.
- Description: Abstract: This paper reports the status quo and impact of leadership in the healthcare sector in South Africa. A gap analysis was conducted in reviewing relevant literature of articles published between 2013-2018 related to the impact of leadership in the country’s healthcare. This was to provide an understanding and clear awareness of the influence leadership has. It was established that leadership in healthcare falls short in addressing critical challenges in the sector. Considering the importance of leadership in healthcare, it is recommended that government should prioritize investing in leadership programs from undergraduate health programs to shelter the future of healthcare in South Africa.
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- Authors: Mukwakungu, Sambil Charles , Mabasa, Matimba Davis , Mbohwa, Charles
- Date: 2018
- Subjects: Leadership , Health Care Practitioners , Health Care System
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/273141 , uj:29093 , Citation: Mukwakungu, S.C., Mabasa, M.D. & Mbohwa, C. 2018. A review on the impact of leadership in healthcare : South African context.
- Description: Abstract: This paper reports the status quo and impact of leadership in the healthcare sector in South Africa. A gap analysis was conducted in reviewing relevant literature of articles published between 2013-2018 related to the impact of leadership in the country’s healthcare. This was to provide an understanding and clear awareness of the influence leadership has. It was established that leadership in healthcare falls short in addressing critical challenges in the sector. Considering the importance of leadership in healthcare, it is recommended that government should prioritize investing in leadership programs from undergraduate health programs to shelter the future of healthcare in South Africa.
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A satisficing approach to home healthcare worker scheduling
- Mutingi, Michael, Mbohwa, Charles
- Authors: Mutingi, Michael , Mbohwa, Charles
- Date: 2013
- Subjects: Home healthcare staff scheduling , Fuzzy sets
- Type: Article
- Identifier: uj:6174 , ISBN 978-93-82242-26-0 , http://hdl.handle.net/10210/13781
- Description: The homecare worker scheduling problem is inundated with fuzzy and often conflicting goals, constraints and preferences. In such an uncertain environment, the decision maker needs to find a satisficing solution approach that takes into account the humanistic judgments and the conflicting nature of the goals. This paper proposes a fuzzy satisficing approach, based on fuzzy set theory, for addressing the homecare worker scheduling problem. The aim is to provide a satisficing approach that considers the management goals, the worker preferences, as well as the service quality as specified by the healthcare clients. By addressing the desired goals or preferences of the three players, (i) the management, (ii) the worker, and (iii) the client, the approach provides a more realistic, flexible and adaptable method for real-world healthcare staff scheduling in an uncertain environment.
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- Authors: Mutingi, Michael , Mbohwa, Charles
- Date: 2013
- Subjects: Home healthcare staff scheduling , Fuzzy sets
- Type: Article
- Identifier: uj:6174 , ISBN 978-93-82242-26-0 , http://hdl.handle.net/10210/13781
- Description: The homecare worker scheduling problem is inundated with fuzzy and often conflicting goals, constraints and preferences. In such an uncertain environment, the decision maker needs to find a satisficing solution approach that takes into account the humanistic judgments and the conflicting nature of the goals. This paper proposes a fuzzy satisficing approach, based on fuzzy set theory, for addressing the homecare worker scheduling problem. The aim is to provide a satisficing approach that considers the management goals, the worker preferences, as well as the service quality as specified by the healthcare clients. By addressing the desired goals or preferences of the three players, (i) the management, (ii) the worker, and (iii) the client, the approach provides a more realistic, flexible and adaptable method for real-world healthcare staff scheduling in an uncertain environment.
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A Study on the leadership behaviour, safety leadership and safety performance in the construction industry in South Africa
- Skeepers, Natalie C., Mbohwa, Charles
- Authors: Skeepers, Natalie C. , Mbohwa, Charles
- Date: 2015
- Subjects: Construction industry - South Africa - Leadership , Construction industry - South Africa - Safety measures , Construction industry - Safety regulations - South Africa
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/68376 , uj:17728 , Citation: Skeepers, N.C. & Mbohwa, C. 2015. A study on the leadership behaviour, safety leadership and safety performance in the construction industry in South Africa
- Description: Abstract: The review of recent publications of employee safety to investigate the relationship between leadership behaviour, safety communication and performance in the construction industry. Method: The study is a cross sectional study, over 348 questionnaires were e-mailed to construction companies in Gauteng, with 155 valid responses received and 44.5% valid response rate achieved. Confirmatory Factor Analysis was carried out to test the factor structure and determine if the composite reliability was significant with a factor loading of > 0.5, resulting in an acceptable model fit. Through the analysis of SPSS, the results show that leadership visibility and behaviour affects safety culture and safety performance in the construction industry. Safety performance was affected and improved with contingency leadership and a positive safety organisational culture. The study suggests improving safety performance by providing well-entrenched safety management systems with the foundation being, safety leadership, communication, commitment and employee training.
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- Authors: Skeepers, Natalie C. , Mbohwa, Charles
- Date: 2015
- Subjects: Construction industry - South Africa - Leadership , Construction industry - South Africa - Safety measures , Construction industry - Safety regulations - South Africa
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/68376 , uj:17728 , Citation: Skeepers, N.C. & Mbohwa, C. 2015. A study on the leadership behaviour, safety leadership and safety performance in the construction industry in South Africa
- Description: Abstract: The review of recent publications of employee safety to investigate the relationship between leadership behaviour, safety communication and performance in the construction industry. Method: The study is a cross sectional study, over 348 questionnaires were e-mailed to construction companies in Gauteng, with 155 valid responses received and 44.5% valid response rate achieved. Confirmatory Factor Analysis was carried out to test the factor structure and determine if the composite reliability was significant with a factor loading of > 0.5, resulting in an acceptable model fit. Through the analysis of SPSS, the results show that leadership visibility and behaviour affects safety culture and safety performance in the construction industry. Safety performance was affected and improved with contingency leadership and a positive safety organisational culture. The study suggests improving safety performance by providing well-entrenched safety management systems with the foundation being, safety leadership, communication, commitment and employee training.
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A systems thinking approach to collaborations for capacity building and sustainability in engineering education
- Nyemba, Wilson R., Carter, Keith F., Mbohwa, Charles, Chinguwa, Simon
- Authors: Nyemba, Wilson R. , Carter, Keith F. , Mbohwa, Charles , Chinguwa, Simon
- Date: 2019
- Subjects: Capacity building , Industry-academia partnerships , Engineering education
- Language: English
- Type: Articles
- Identifier: http://hdl.handle.net/10210/295135 , uj:32129 , Citation: Nyemba, W.R. et al. 2019. A systems thinking approach to collaborations for capacity building and sustainability in engineering education.
- Description: Abstract: Please refer to full text to view abstract.
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- Authors: Nyemba, Wilson R. , Carter, Keith F. , Mbohwa, Charles , Chinguwa, Simon
- Date: 2019
- Subjects: Capacity building , Industry-academia partnerships , Engineering education
- Language: English
- Type: Articles
- Identifier: http://hdl.handle.net/10210/295135 , uj:32129 , Citation: Nyemba, W.R. et al. 2019. A systems thinking approach to collaborations for capacity building and sustainability in engineering education.
- Description: Abstract: Please refer to full text to view abstract.
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