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Publications

Publications by SEM

2024

Educational Practices and Strategies With Immersive Learning Environments: Mapping of Reviews for Using the Metaverse

Authors
Beck, D; Morgado, L; O'Shea, P;

Publication
IEEE TRANSACTIONS ON LEARNING TECHNOLOGIES

Abstract
The educational metaverse promises fulfilling ambitions of immersive learning, leveraging technology-based presence alongside narrative and/or challenge-based deep mental absorption. Most reviews of immersive learning research were outcomes-focused, few considered the educational practices and strategies. These are necessary to provide theoretical and pedagogical frameworks to situate outcomes within a context where technology is in concert with educational approaches. We sought a broader perspective of the practices and strategies used in immersive learning environments, and conducted a mapping survey of reviews, identifying 47 studies. Extracted accounts of educational practices and strategies under thematic analysis yielded 45 strategies and 21 practices, visualized as a network clustered by conceptual proximity. Resulting clusters Active context, Collaboration, Engagement and Scaffolding, Presence, and Real and virtual multimedia learning expose the richness of practices and strategies within the field. The visualization maps the field, supporting decision-making when combining practices and strategies for using the metaverse in education, highlights which practices and strategies are supported by the literature, and the presence and absence of diversity within clusters.

2024

Energy-efficient job shop scheduling problem with transport resources considering speed adjustable resources

Authors
Fontes, DBMM; Homayouni, SM; Fernandes, JC;

Publication
INTERNATIONAL JOURNAL OF PRODUCTION RESEARCH

Abstract
This work extends the energy-efficient job shop scheduling problem with transport resources by considering speed adjustable resources of two types, namely: the machines where the jobs are processed on and the vehicles that transport the jobs around the shop-floor. Therefore, the problem being considered involves determining, simultaneously, the processing speed of each production operation, the sequence of the production operations for each machine, the allocation of the transport tasks to vehicles, the travelling speed of each task for the empty and for the loaded legs, and the sequence of the transport tasks for each vehicle. Among the possible solutions, we are interested in those providing trade-offs between makespan and total energy consumption (Pareto solutions). To that end, we develop and solve a bi-objective mixed-integer linear programming model. In addition, due to problem complexity we also propose a multi-objective biased random key genetic algorithm that simultaneously evolves several populations. The computational experiments performed have show it to be effective and efficient, even in the presence of larger problem instances. Finally, we provide extensive time and energy trade-off analysis (Pareto front) to infer the advantages of considering speed adjustable machines and speed adjustable vehicles and provide general insights for the managers dealing with such a complex problem.

2024

A literature review of economic efficiency assessments using Data Envelopment Analysis

Authors
Camanho, AS; Silva, MC; Piran, FS; Lacerda, DP;

Publication
EUROPEAN JOURNAL OF OPERATIONAL RESEARCH

Abstract
This paper presents a literature review on Data Envelopment Analysis assessments of economic efficiency, covering methodological developments and empirical applications. We review the seminal models for economic efficiency measurement, involving the optimization of cost, revenue, and profit. The applications of the different modelling approaches are also discussed. Based on a content analysis of papers published between 1978 and 2020 in various sectors, the main areas of study are identified, and the pathways of research developments are discussed. Most studies are based on disaggregated quantity and price data. In addition, the use of panel data is prevalent compared to cross-sectional studies. There is a preponderance of input -oriented studies focused on cost efficiency rather than revenue or profit efficiency. Informed by the historical evolution of economic efficiency assessments portrayed in this review, we suggest directions for future developments. (c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )

2024

Synchronisation in vehicle routing: Classification schema, modelling framework and literature review

Authors
Soares, R; Marques, A; Amorim, P; Parragh, SN;

Publication
EUROPEAN JOURNAL OF OPERATIONAL RESEARCH

Abstract
The practical relevance and challenging nature of the Vehicle Routing Problem (VRP) have motivated the Operations Research community to consider different practical requirements and problem variants throughout the years. However, businesses still face increasingly specific and complex transportation re-quirements that need to be tackled, one of them being synchronisation. No literature contextualises syn-chronisation among other types of problem aspects of the VRP, increasing ambiguity in the nomenclature used by the community. The contributions of this paper originate from a literature review and are three-fold. First, new conceptual and classification schemas are proposed to analyse literature and re-organise different interdependencies that arise in routing decisions. Secondly, a modelling framework is presented based on the proposed schemas. Finally, an extensive literature review identifies future research gaps and opportunities in the field of VRPs with synchronisation.(c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )

2024

Deep Reinforcement Learning-Based Approach to Dynamically Balance Multi-manned Assembly Lines

Authors
Santos, R; Marques, C; Toscano, C; Ferreira, M; Ribeiro, J;

Publication
Lecture Notes in Mechanical Engineering

Abstract
Assembly lines are at the core of many manufacturing systems, and planning for a well-balanced flow is key to ensure long-term efficiency. However, in flexible configurations such as Multi-Manned Assembly Lines (MMAL), the balancing problem also becomes more challenging. Due to the increased relevance of these assembly lines, this work aims to investigate the MMAL balancing problem, to contribute for a more effective decision-making process. Therefore, a new approach is proposed based on Deep Reinforcement Learning (DRL) embedded in a Digital Twin architecture. The proposed approach provides a close-to-reality training environment for the agent, using Discrete Event Simulation to simulate the production system dynamics. This methodology was tested on a real-world instance with preliminary results showing that similar solutions to the ones obtained using optimization-based strategies are achieved. This research provides evidence of success in terms of dynamic resource assignment to tasks and workers as a basis for future developments. © 2024, The Author(s), under exclusive license to Springer Nature Switzerland AG.

2023

The assessment of performance trends and convergence in education and training systems of European countries

Authors
Camanho, AS; Stumbriene, D; Barbosa, F; Jakaitiene, A;

Publication
EUROPEAN JOURNAL OF OPERATIONAL RESEARCH

Abstract
The Strategic Framework for European Cooperation in Education and Training (ET 2020) aimed to pro-mote the exchange of best practices among the Member States. This paper assesses the performance evo-lution of European countries in terms of the common objectives for the education sector. The framework used to evaluate European education systems is based on constructing a composite indicator adopting a benefit-of-the-doubt approach. The evaluation of performance change over time is done using a Global Malmquist Index. Sigma and beta convergence of EU countries are also explored using non-parametric frontier techniques. The results are analysed for the period 2009-2018 and discussed in light of the goals envisaged and the national policies adopted. The results revealed a trend of improvement in the perfor-mance of education systems in most European countries in the period analysed. Although most European countries moved closer to the European best practice frontier over time, as confirmed by the values of sigma-convergence, a few countries are still lagging considerably below their peers, as revealed by the existence of divergence in beta.(c) 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )

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