Browsing by Author "Ebufegha, Akposeiyifa Joseph"

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    Decentralized Scheduling Using The Multi-Agent System Approach For Smart Manufacturing Systems: Investigation And Design
    (2023-09-20) Ebufegha, Akposeiyifa Joseph; Li, Simon; Brennan, Robert; Lee, Jihyun
    The advent of industry 4.0 has resulted in increased availability, velocity, and volume of data as well as increased data processing capabilities. There is a need to determine how best to incorporate these advancements to improve the performance of manufacturing systems. The purpose of this research is to present a solution for incorporating industry 4.0 into manufacturing systems. It will focus on how such a system would operate, how to select resources for the system, and how to configure the system. Our proposed solution is a smart manufacturing system that operates as a self-coordinating system. It utilizes a multi-agent system (MAS) approach, where individual entities within the system have autonomy to make dynamic scheduling decisions in real-time. This solution was shown to outperform alternative scheduling strategies (right shifting and dispatching priority rule) in manufacturing environments subject to uncertainty in our simulation experiments. The second phase of our research focused on system design. This phase involved developing models for two problems: (1) resource selection, and (2) layout configuration. Both models developed use simulation-based optimization. We first present a model for determining machine resources using a genetic algorithm (GA). This model yielded results comparable to an exhaustive search whilst significantly reducing the number of required experiments to find the solution. To address layout configuration, we developed a model that combines hierarchical clustering and GA. Our numerical experiments demonstrated that the hybrid layouts derived from the model result in shorter and less variable order completion times compared to alternative layout configurations. Overall, our research showed that MAS-based scheduling can outperform alternative dynamic scheduling approaches in manufacturing environments subject to uncertainty. We also show that this performance can further be improved through optimal resource selection and layout design.
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    Design Project Scheduling with Probabilistic Iterations: Optimization & Investigation of Robustness
    (2018-09-05) Ebufegha, Akposeiyifa Joseph; Li, Simon; Tu, Paul; Xue, Deyi; Sadeghpour, Farnaz
    This research focuses on reliable prediction of product development (PD) project duration within reasonable solution times. It is based on the model of PD projects presented by Smith and Eppinger which suggests that PD projects are akin to Markov reward chains. The research was divided into two phases; the development of a hybrid algorithm to minimize the problem’s solve time without compromising solution quality and the identification of features of a robust PD schedule. The first phase of the research shows that the hybrid algorithm yields similar quality solutions whilst reducing solve times by 50% - 97.4%. The second phase highlights four features that affect robust PD schedule as well as patterns observed in the schedule. In conclusion, this research demonstrates the utility of the developed hybrid algorithm and also illustrates the importance of examining expected project duration and the standard deviation in the results when developing robust PD schedules.