This paper explores how small and medium-sized e-grocery mobile application retailers evolving wi... more This paper explores how small and medium-sized e-grocery mobile application retailers evolving within the geographical context of South Africa and operating in the urban, township, and rural areas respond to theoretically and emerging field-based e-business and e-grocery adoption challenges, respectively. The study used semi-structured qualitative interviews to explore the coping strategies of e-grocery mobile application retailers to mitigate technological, organizational, and environmental (TOE) adoption challenges. The significance of small grocery adoption strategies related to context informs e-grocery adoption from the evidence generated in other small e-grocers and for the superior grade of TOE (or theoretical) knowledge sought from the inevitable evolving mobile application and digital grocery markets. The findings reveal that specialist skills and unified team production are crucial conduits for lowering the TOE barriers to e-business and e-grocery adoption. They also revea...
This work presents a simulation study of the check-in system at the Ottawa International Airport.... more This work presents a simulation study of the check-in system at the Ottawa International Airport. Various data were collected and used to define the inputs to a simulation model. These include the current agents' working schedules, the passengers' arrival pattern distributions, the passengers' service time distributions, the historical flight load factor, the distributions of the types of passengers, and the flight schedule. The scenarios evaluated include changing the queue structure and considering alternate agents' working schedules. The performance measurement retained are the average waiting time in queues, the maximum waiting time in queues, the average queue length, the maximum queue length, and the distribution of passengers waiting times in queues. A linear programming (LP) model was developed to provide alternate agent working schedules that minimizes the total agent person hours and meets the passenger loads that vary throughout the day. A heuristic was us...
This paper discusses a general nonlinear optimization model for the problem of investing in reduc... more This paper discusses a general nonlinear optimization model for the problem of investing in reduced setup times and process improvements for a manufacturer of several products operating in a JIT environment. Demand for each product occurs at a constant rate. The problem is constrained by limitations on the process improvement and setup reduction budgets, and on the manufacturing and warehousing capacities. The objective is to determine optimal levels of setup time and process improvements along with the corresponding amounts of investments respectively, and the optimal production cycle time for each product. A convex geometric programming model of this problem is developed in order to solve it. In order to deal with numerical difficulties that may be encountered in practice, a dual reformulation of the model is discussed.
2015 48th Hawaii International Conference on System Sciences, 2015
This work describes and illustrates the use of simulation modeling for evaluating and analyzing t... more This work describes and illustrates the use of simulation modeling for evaluating and analyzing the impacts of workflow changes in healthcare resulting from the deployment of a computerized provider order entry (CPOE) system. It is motivated by our longitudinal research program which purports to explore simulation modeling as one of the means that can be applied not merely to contribute to an increased acceptance and use of CPOE systems, but also to aid in decision making. The setting used is The Ottawa Hospital, one of the Canada's largest teaching hospitals, and its multi-phase, multi-year CPOE deployment project for laboratory and diagnostic imaging orders to improve both patient safety and quality of care. The preliminary results indicate that the proposed simulation-based tool can be effectively applied in its current level of development to quantitatively evaluate and compare different options of workflow changes within a given set of operational and organizational constraints.
International Journal of Production Research, 2015
We examine the problem of planning the supply of rewards in coalition loyalty programmes consider... more We examine the problem of planning the supply of rewards in coalition loyalty programmes considering that the buyer–supplier relationships with commercial partners are governed by option contracts rather than wholesale price contracts similar to what is commonly used in practice. We develop a two-stage stochastic linear programme model with simple recourse which considers uncertain demand requirements, limited reward purchasing budgets, multiple programme partners of various sizes, point-liability control targets and overall profitability. A sampling average approximation scheme is used to solve the model. Numerical experiments show that option contracts perform better than wholesale price contracts when redemption demand uncertainty is high and the number of redemption partners is large. The results also suggest that the common practice of increasing redemption capacities is not the most effective way to cope with demand uncertainties. Programmes that reduce redemption demand variability and/or create better contracting structures are more promising in improving points-liability, redemption budget spending and overall profitability than traditional approaches.
Communications in Computer and Information Science, 2010
Loyalty reward programs (LRPs), initially developed as marketing programs to enhance customer ret... more Loyalty reward programs (LRPs), initially developed as marketing programs to enhance customer retention, have now become an important part of customer-focused business strategy. With the proliferation and increasing economy impact of the programs, the management complexity in the programs has also increased. However, despite widespread adoption of LRPs in business, academic research in the field seems to lag behind its
ABSTRACT Coalition loyalty programmes (CLPs) are owned and operated as for-profit enterprises. We... more ABSTRACT Coalition loyalty programmes (CLPs) are owned and operated as for-profit enterprises. We consider the ordering decisions of rewards that arise in this context, under a general setting in which not only is the demand for rewards uncertain, but also the CLP firm offers bonus points, a very common cooperative promotion mechanism used in loyalty programmes. The rewards are acquired either at a wholesale ‘discounted’ cost or at a wholesale ‘non-discounted’ cost by the CLP firm from its multiple commercial partners and supplied to customers seeking to redeem their accumulated ‘reward points’, subject to commercial partners’ capacities for offering rewards, the firm’s overall budget for purchasing rewards, and its control policy on points liability. We formulate the problem as a stochastic linear programme with recourse and solve it using a sampling-based heuristic solution procedure previously discussed in the literature. We report on the managerial applicability of our model in dealing with the redemption budget spending resulting from changes in demand variability, changes in the redemption budget, and the control of liability levels within a reasonable range.
We develop a Lagrangean relaxation-based heuristic procedure to generate a near-optimal solution ... more We develop a Lagrangean relaxation-based heuristic procedure to generate a near-optimal solution to large-scale capacitated part-routing problems through a cellular manufacturing system with both routing flexibilities and setup times. Several alternate process plans exist for each product. Any given operation can be performed on alternate machines at different costs. The part demands can be satisfied from internal production or through outsourcing. The objective is to minimize the total material handling, production, outsourcing, and setup costs, subject to satisfying all the part demands and not exceeding any of the machine capacity limits. Our computational experiments show that large problems involving several thousand products and decision variables can be solved in a reasonable amount of computer time to within 1% of their optimal solutions. The proposed procedure is general enough to be applied directly or with slight modifications to real-life, industrial-sized problems.
International Journal of Production Research, 2009
We consider the problem of planning the production steps of several parts through a manufacturing... more We consider the problem of planning the production steps of several parts through a manufacturing system with both process and routing flexibilities. The problem is formulated as a network flow-based linear programming model which seeks to minimise the total material handling, production, and outsourcing costs subject to satisfying all the part demands and not exceeding any of the machine capacity
This paper explores how small and medium-sized e-grocery mobile application retailers evolving wi... more This paper explores how small and medium-sized e-grocery mobile application retailers evolving within the geographical context of South Africa and operating in the urban, township, and rural areas respond to theoretically and emerging field-based e-business and e-grocery adoption challenges, respectively. The study used semi-structured qualitative interviews to explore the coping strategies of e-grocery mobile application retailers to mitigate technological, organizational, and environmental (TOE) adoption challenges. The significance of small grocery adoption strategies related to context informs e-grocery adoption from the evidence generated in other small e-grocers and for the superior grade of TOE (or theoretical) knowledge sought from the inevitable evolving mobile application and digital grocery markets. The findings reveal that specialist skills and unified team production are crucial conduits for lowering the TOE barriers to e-business and e-grocery adoption. They also revea...
This work presents a simulation study of the check-in system at the Ottawa International Airport.... more This work presents a simulation study of the check-in system at the Ottawa International Airport. Various data were collected and used to define the inputs to a simulation model. These include the current agents' working schedules, the passengers' arrival pattern distributions, the passengers' service time distributions, the historical flight load factor, the distributions of the types of passengers, and the flight schedule. The scenarios evaluated include changing the queue structure and considering alternate agents' working schedules. The performance measurement retained are the average waiting time in queues, the maximum waiting time in queues, the average queue length, the maximum queue length, and the distribution of passengers waiting times in queues. A linear programming (LP) model was developed to provide alternate agent working schedules that minimizes the total agent person hours and meets the passenger loads that vary throughout the day. A heuristic was us...
This paper discusses a general nonlinear optimization model for the problem of investing in reduc... more This paper discusses a general nonlinear optimization model for the problem of investing in reduced setup times and process improvements for a manufacturer of several products operating in a JIT environment. Demand for each product occurs at a constant rate. The problem is constrained by limitations on the process improvement and setup reduction budgets, and on the manufacturing and warehousing capacities. The objective is to determine optimal levels of setup time and process improvements along with the corresponding amounts of investments respectively, and the optimal production cycle time for each product. A convex geometric programming model of this problem is developed in order to solve it. In order to deal with numerical difficulties that may be encountered in practice, a dual reformulation of the model is discussed.
2015 48th Hawaii International Conference on System Sciences, 2015
This work describes and illustrates the use of simulation modeling for evaluating and analyzing t... more This work describes and illustrates the use of simulation modeling for evaluating and analyzing the impacts of workflow changes in healthcare resulting from the deployment of a computerized provider order entry (CPOE) system. It is motivated by our longitudinal research program which purports to explore simulation modeling as one of the means that can be applied not merely to contribute to an increased acceptance and use of CPOE systems, but also to aid in decision making. The setting used is The Ottawa Hospital, one of the Canada's largest teaching hospitals, and its multi-phase, multi-year CPOE deployment project for laboratory and diagnostic imaging orders to improve both patient safety and quality of care. The preliminary results indicate that the proposed simulation-based tool can be effectively applied in its current level of development to quantitatively evaluate and compare different options of workflow changes within a given set of operational and organizational constraints.
International Journal of Production Research, 2015
We examine the problem of planning the supply of rewards in coalition loyalty programmes consider... more We examine the problem of planning the supply of rewards in coalition loyalty programmes considering that the buyer–supplier relationships with commercial partners are governed by option contracts rather than wholesale price contracts similar to what is commonly used in practice. We develop a two-stage stochastic linear programme model with simple recourse which considers uncertain demand requirements, limited reward purchasing budgets, multiple programme partners of various sizes, point-liability control targets and overall profitability. A sampling average approximation scheme is used to solve the model. Numerical experiments show that option contracts perform better than wholesale price contracts when redemption demand uncertainty is high and the number of redemption partners is large. The results also suggest that the common practice of increasing redemption capacities is not the most effective way to cope with demand uncertainties. Programmes that reduce redemption demand variability and/or create better contracting structures are more promising in improving points-liability, redemption budget spending and overall profitability than traditional approaches.
Communications in Computer and Information Science, 2010
Loyalty reward programs (LRPs), initially developed as marketing programs to enhance customer ret... more Loyalty reward programs (LRPs), initially developed as marketing programs to enhance customer retention, have now become an important part of customer-focused business strategy. With the proliferation and increasing economy impact of the programs, the management complexity in the programs has also increased. However, despite widespread adoption of LRPs in business, academic research in the field seems to lag behind its
ABSTRACT Coalition loyalty programmes (CLPs) are owned and operated as for-profit enterprises. We... more ABSTRACT Coalition loyalty programmes (CLPs) are owned and operated as for-profit enterprises. We consider the ordering decisions of rewards that arise in this context, under a general setting in which not only is the demand for rewards uncertain, but also the CLP firm offers bonus points, a very common cooperative promotion mechanism used in loyalty programmes. The rewards are acquired either at a wholesale ‘discounted’ cost or at a wholesale ‘non-discounted’ cost by the CLP firm from its multiple commercial partners and supplied to customers seeking to redeem their accumulated ‘reward points’, subject to commercial partners’ capacities for offering rewards, the firm’s overall budget for purchasing rewards, and its control policy on points liability. We formulate the problem as a stochastic linear programme with recourse and solve it using a sampling-based heuristic solution procedure previously discussed in the literature. We report on the managerial applicability of our model in dealing with the redemption budget spending resulting from changes in demand variability, changes in the redemption budget, and the control of liability levels within a reasonable range.
We develop a Lagrangean relaxation-based heuristic procedure to generate a near-optimal solution ... more We develop a Lagrangean relaxation-based heuristic procedure to generate a near-optimal solution to large-scale capacitated part-routing problems through a cellular manufacturing system with both routing flexibilities and setup times. Several alternate process plans exist for each product. Any given operation can be performed on alternate machines at different costs. The part demands can be satisfied from internal production or through outsourcing. The objective is to minimize the total material handling, production, outsourcing, and setup costs, subject to satisfying all the part demands and not exceeding any of the machine capacity limits. Our computational experiments show that large problems involving several thousand products and decision variables can be solved in a reasonable amount of computer time to within 1% of their optimal solutions. The proposed procedure is general enough to be applied directly or with slight modifications to real-life, industrial-sized problems.
International Journal of Production Research, 2009
We consider the problem of planning the production steps of several parts through a manufacturing... more We consider the problem of planning the production steps of several parts through a manufacturing system with both process and routing flexibilities. The problem is formulated as a network flow-based linear programming model which seeks to minimise the total material handling, production, and outsourcing costs subject to satisfying all the part demands and not exceeding any of the machine capacity
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Papers by Aaron Nsakanda