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Publications

Publications by SYSTEM

2025

A production quality monitoring approach based on a condition index: an application on the glass container industry

Authors
Oliveira, MA; Guimaraes, L; Borges, JL; Almada Lobo, B;

Publication
INTERNATIONAL JOURNAL OF PRODUCTION RESEARCH

Abstract
Ensuring process quality in modern manufacturing is increasingly challenging due to the complexity of production processes and reliance on skilled operators, which can lead to suboptimal solutions and poor quality. To address these challenges, we introduce a novel, unsupervised, robust, nonparametric control chart for Phase II monitoring. This chart tracks the degradation of a quality characteristic using a condition index that captures mean and scale shifts without relying on assumptions, offering high flexibility and adaptability. Comparative studies with state-of-the-art nonparametric schemes demonstrate faster detection capabilities and competitive accuracy across various scenarios. We validate our approach through its application in the glass container production process, showcasing its effectiveness in monitoring multiple defective rates. Although tested on defective rates, the methodology is adaptable to any quantifiable quality characteristic.

2025

Exploring the impacts of Industry 4.0 technologies on the triple bottom line of sustainability in industrial companies

Authors
Almeida, D; Simoes, AC; Fernandes, A;

Publication
INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY

Abstract
Industrial companies operate in a context of dynamic technological innovation, in which new technologies are adopted with a high impact internally and externally, leveraging their competitive advantages. Usually, managers decide to adopt technologies, often without realising the impacts on the company, but mainly supported by a strategic vision and the pursuit of differentiation. This study aims to describe the impacts of adopting Industry 4.0 technologies in industrial companies, focusing on sustainability's economic, social, and environmental dimensions and explaining which Industry 4.0 technologies contribute to each impact. This study used qualitative methodology, collecting data through interviews, internal documents, and observation. The results of this study identified new impacts in the three dimensions of sustainability, as well as the relationships between impacts and respective technologies. This study contributes to the literature by enriching and validating the impacts of adopting Industry 4.0 technologies on sustainability dimensions and linking these impacts with the technologies. In practice, it provides important insights to managers and decision-makers of manufacturing companies in making more informed decisions on adopting i4.0 technologies.

2025

User Acceptance in Human-Robot Interaction: Exploring the Role of Anthropomorphic Mechanisms in Manufacturing Environments-A Systematic Literature Review

Authors
Pinto, A; Solovov, A; Simoes, AC; Menezes, P;

Publication
JOURNAL OF INTELLIGENT & ROBOTIC SYSTEMS

Abstract
In pursuing Industry 5.0's vision, which emphasises human well-being and the seamless integration of robots into manufacturing processes, understanding the role of anthropomorphic design is crucial. Anthropomorphic design, where robots exhibit human-like, animal-like, or even entirely novel traits (e.g. a display scrolling text), aims to improve human-robot interaction (HRI) and enhance human acceptance within manufacturing contexts. Understanding the optimal degree of human-readable characteristics in robots is essential for further advancements in this domain. This systematic literature review aims to identify anthropomorphic mechanisms in HRI and their effect on human acceptance in manufacturing. Using the PRISMA methodology, a systematic literature review was conducted across the WOS, EBSCO, and SCOPUS databases, resulting in the selection of four articles for final analysis. A quality assessment of the articles was conducted. On a scale of 0 to 16, article scores ranged from 10 to 15, with an average score of 13. The findings indicate that while current research provides valuable insights, it has predominantly focused on conventional anthropomorphic mechanisms from social robotics, such as basic human-like features (e.g., facial expressions, gestures), without exploring more advanced or novel traits. This highlights significant room for further exploration and innovation in industrial settings to enhance user acceptance and interaction. The study underscores the necessity for continued research and development to leverage advanced anthropomorphic designs that can better fulfil the goals of Industry 5.0.

2025

Discovering user groups of active modes of transport in urban centers using clustering methods

Authors
Felicio, S; Hora, J; Ferreira, MC; Sobral, T; Camacho, R; Galvao, T;

Publication
JOURNAL OF TRANSPORT & HEALTH

Abstract
Introduction: Urban centers face increasing congestion and pollution due to population growth driven by jobs, education, and entertainment. Promoting active modes like walking and cycling offers healthier and less polluting alternatives. Understanding perceptions of comfort (green areas, commercial areas, crowd density, noise, thermal sensation, air quality, allergenics), safety and security (street illumination, traffic volume, surveillance, visual appearance, and speed limits) are crucial for encouraging active modes adoption. This study categorizes user groups based on these indicators, supporting policymakers in the development of targeted strategies. Methods: We developed a questionnaire to support our empirical study and collected 653 responses. We have analyzed the data using clustering methods such as Affinity Propagation, BIRCH, Bisecting K-means, HAC, K-means, Mini-Batch K-means, and Spectral clustering. The best performing method (K-means) was used to identify the user groups while a random forest model evaluated the relative importance of indicators for each group. Results: The study identified five user groups based on urban mobility indicators for safety and security, comfort, and distance and time. Conclusions: These groups, distinguished by sociodemographic features, include: Street Aesthetes (young men valuing visual appeal), Safety Seekers (employed men prioritizing speed limits), Working Guardians (employed men focused on surveillance and green spaces), Urban Explorers (young women valuing air quality and low traffic), and Comfort Connoisseurs (employed women prioritizing noise reduction and aesthetics).

2025

Improving warehouse operations: leveraging simulation for efficient layout design and process improvement in a picking by line operation

Authors
de Carvalho Paula, M; Carvalho, MS; Silva, E;

Publication
Procedia Computer Science

Abstract
This study focuses on improving the picking processes within a Picking-by-Line (PBL) warehouse through the development of a simulation model to assess different layouts and new operational rules. Utilizing a combination of Discrete Event Simulation (DES) and Agent-Based Modeling (ABS) in AnyLogic, the simulation model was validated against real-world Key Performance Indicators (KPIs) to ensure accuracy. The study identified three primary improvement opportunities. To address these opportunities, four scenarios were tested. The results showed varying impacts on productivity, with three of the four scenarios yielding improvements in picking productivity. Pilot testing confirmed the simulation model's predictions. The findings indicate that balancing travel distance reduction with congestion management is key to increasing picking productivity. This study reaffirms the value of simulation modeling in warehouse management, providing a robust framework for free-risk testing. © 2025 Elsevier B.V., All rights reserved.

2025

Anew effective heuristic for the Prisoner Transportation Problem

Authors
Ferreira, L; Maciel, MVM; de Carvalho, JV; Silva, E; Alvelos, FP;

Publication
EUROPEAN JOURNAL OF OPERATIONAL RESEARCH

Abstract
The Prisoner Transportation Problem is an NP-hard combinatorial problem and a complex variant of the Dial-a- Ride Problem. Given a set of requests for pick-up and delivery and a homogeneous fleet, it consists of assigning requests to vehicles to serve all requests, respecting the problem constraints such as route duration, capacity, ride time, time windows, multi-compartment assignment of conflicting prisoners and simultaneous services in order to optimize a given objective function. In this paper, we present anew solution framework to address this problem that leads to an efficient heuristic. A comparison with computational results from previous papers shows that the heuristic is very competitive for some classes of benchmark instances from the literature and clearly superior in the remaining cases. Finally, suggestions for future studies are presented.

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