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Publicações

Publicações por SYSTEM

2024

A Data-Driven Monitoring Approach for Diagnosing Quality Degradation in a Glass Container Process

Autores
Oliveira, MA; Guimaraes, L; Borges, JL; Almada-Lobo, B;

Publicação
MACHINE LEARNING, OPTIMIZATION, AND DATA SCIENCE, LOD 2023, PT I

Abstract
Maintaining process quality is one of the biggest challenges manufacturing industries face, as production processes have become increasingly complex and difficult to monitor effectively in today's manufacturing contexts. Reliance on skilled operators can result in suboptimal solutions, impacting process quality. In doing so, the importance of quality monitoring and diagnosis methods cannot be undermined. Existing approaches have limitations, including assumptions, prior knowledge requirements, and unsuitability for certain data types. To address these challenges, we present a novel unsupervised monitoring and detection methodology to monitor and evaluate the evolution of a quality characteristic's degradation. To measure the degradation we created a condition index that effectively captures the quality characteristic's mean and scale shifts from the company's specification levels. No prior knowledge or data assumptions are required, making it highly flexible and adaptable. By transforming the unsupervised problem into a supervised one and utilising historical production data, we employ logistic regression to predict the quality characteristic's conditions and diagnose poor condition moments by taking advantage of the model's interpretability. We demonstrate the methodology's application in a glass container production process, specifically monitoring multiple defective rates. Nonetheless, our approach is versatile and can be applied to any quality characteristic. The ultimate goal is to provide decision-makers and operators with a comprehensive view of the production process, enabling better-informed decisions and overall product quality improvement.

2024

Matheuristic for the lot-sizing and scheduling problem in integrated pulp and paper production

Autores
Furlan, M; Almada Lobo, B; Santos, M; Morabito, R;

Publicação
COMPUTERS & INDUSTRIAL ENGINEERING

Abstract
Vertical pulp and paper production is challenging from a process point of view. Managers must deal with floating bottlenecks, intermediate storage levels, and by-product production to control the whole process while reducing unexpected downtimes. Thus, this paper aims to address the integrated lot sizing and scheduling problem considering continuous digester production, multiple paper machines, and a chemical recovery line to treat by-products. The aim is to minimize the total production cost to meet customer demands, considering all productive resources and encouraging steam production (which can be used in power generation). Production planning should define the sizes of production lots, the sequence of paper types produced in each machine, and the digester working speed throughout the planning horizon. Furthermore, it should indicate the rate of byproduct treatment at each stage of the recovery line and ensure the minimum and maximum storage limits. Due to the difficulty of exactly solving the mixed integer programming model representing this problem for realworld instances, mainly with planning horizons of over two weeks, constructive and improvement heuristics are proposed in this work. Different heuristic combinations are tested on hundreds of instances generated from data collected from the industry. Comparisons are made with a commercial Mixed-Integer and Linear Programming solver and a hybrid metaheuristic. The results show that combining the greedy constructive heuristic with the new variation of a fix-and-optimize improvement method delivers the best performance in both solution quality and computational time and effectively solves realistic size problems in practice. The proposed method achieved 69.41% of the best solutions for the generated set and 55.40% and 64.00% for the literature set for 1 and 2 machines, respectively, compared with the best solution method from the literature and a commercial solver.

2024

COGNITIVE WORKLOAD AND FATIGUE IN A HUMAN-ROBOT COLLABORATIVE ASSEMBLY WORKSTATION: A PILOT STUDY

Autores
Joana Santos; Mariana Ferraz; Ana Pinto; Luis F. Rocha; Carlos M. Costa; Ana C. Simões; Klass Bombeke; M.A.P. Vaz;

Publicação
International Symposium on Occupational Safety and Hygiene: Proceedings Book of the SHO2023

Abstract

2024

Business Model Revolution: Unleashing Innovation Through Digitalisation, Servitisation and Collaborative Research in Industrial Companies

Autores
Mesquita, M; Simões, AC; Teles, V; Dalmarco, G;

Publicação
Lecture Notes in Mechanical Engineering

Abstract
Companies are putting more emphasis on the customer experience, associating services with their physical products with the help of emerging technologies. At the same time, several actors participating in research and innovation projects, such as universities, research institutes, and service providers, are involved in the value co-creation process. Thus, this study describes how digitalisation and servitisation in the context of participation in research and innovation projects contributed to innovation in industrial companies’ business model (BM). Qualitative exploratory research took place, collecting data through interviews with twelve key actors in industrial companies. The interviewees were professionals in management and R&D areas and founders from nine European countries who participated in six research and innovation European projects. The exchange of knowledge and experiences between the different actors of the innovation ecosystem influences this. From a practical point of view, research provides managers of industrial companies with the best practices and describes the main changes observed in the BM Canvas. This study also contributes to categorising companies in terms of their service maturity by associating factors other than servitisation, such as digitalisation and the actors of the research and innovation projects. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.

2024

Burnout and coping strategies among Professors during COVID-19: Portugal-Brazil comparative study

Autores
Pinto, A; Carvalho, C; Rodriguez, S; Simões, A; Carvalhais, C; Gonçalves, FJ; Santos, J;

Publicação
Atlantis Highlights in Social Sciences, Education and Humanities - International Conference on Lifelong Education and Leadership for All (ICLEL 2023)

Abstract

2024

What Matters for Managers When Adopting Cobots in Manufacturing Organisations? - The Results of a Survey Study in Portuguese SMEs

Autores
Couto, G; Simoes, AC; Ferreira, LMDF; Sousa, PSA; Moreira, MRA; Ribeiro, FL;

Publicação
ADVANCES IN PRODUCTION MANAGEMENT SYSTEMS-PRODUCTION MANAGEMENT SYSTEMS FOR VOLATILE, UNCERTAIN, COMPLEX, AND AMBIGUOUS ENVIRONMENTS, APMS 2024, PT III

Abstract
Collaborative robots, or cobots, are increasingly used by manufacturing companies to meet the demands for greater flexibility and to adapt to the trend of mass customisation in production. When considering the adoption of cobots, companies enter a critical decision-making phase. This study aims to identify the relevant decision factors for adopting collaborative robots (cobots) in manufacturing medium-sized enterprises (SMEs) in Portugal, using a combined framework of Technology-Organisation-Environment (TOE), Diffusion of Innovations (DOI) theory, and Institutional Theory. Data was collected through an online survey distributed to Portuguese manufacturing companies, yielding 78 valid responses. Analysis conducted using SmartPLS 4 revealed that top management support, resource availability, and industry pressure significantly influence the adoption decision. However, factors such as the relative advantage of cobots, compatibility with existing processes, organisational innovativeness, human resources quality, and external support did not significantly impact SMEs' adoption of cobots. These findings enhance the understanding of technology management, specifically the process of adopting cobots in manufacturing. The insights from this study help managers focus on the key factors critical for successful cobot adoption, supporting decision-makers in making more informed choices.

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