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Publicações

2025

Reducing algorithm configuration spaces for efficient search

Autores
Freitas, F; Brazdil, P; Soares, C;

Publicação
INTERNATIONAL JOURNAL OF DATA SCIENCE AND ANALYTICS

Abstract
Many current AutoML platforms include a very large space of alternatives (the configuration space). This increases the probability of including the best one for any dataset but makes the task of identifying it for a new dataset more difficult. In this paper, we explore a method that can reduce a large configuration space to a significantly smaller one and so help to reduce the search time for the potentially best algorithm configuration, with limited risk of significant loss of predictive performance. We empirically validate the method with a large set of alternatives based on five ML algorithms with different sets of hyperparameters and one preprocessing method (feature selection). Our results show that it is possible to reduce the given search space by more than one order of magnitude, from a few thousands to a few hundred items. After reduction, the search for the best algorithm configuration is about one order of magnitude faster than on the original space without significant loss in predictive performance.

2025

DFDT: Dynamic Fast Decision Tree for IoT Data Stream Mining on Edge Devices

Autores
Lourenço, A; Rodrigo, J; Gama, J; Marreiros, G;

Publicação
CoRR

Abstract

2025

A 3-level integrated lot sizing and cutting stock problem applied to a truck suspension factory

Autores
Andrade, PRD; De Araujo, SA; Cherri, AC; Lemos, FK;

Publicação
TOP

Abstract
This paper studies the process of cutting steel bars in a truck suspension factory with the objective of reducing its inventory costs and material losses. A mathematical model is presented that focuses on decisions for a medium-term horizon (4 periods of 2 months). This approach addresses the one-dimensional 3-level integrated lot sizing and cutting stock problem, considering demand, inventory costs and stock level limits for bars (objects-level 1), springs (items-level 2) and spring bundles (final products-level 3), as well as the acquisition of bars as a decision variable. The solution to the proposed mathematical model is reached through an optimization package, using column generation along with a method for achieving integer solutions. The results obtained with real data demonstrate that the method provides significantly better solutions than those carried out at the company, whilst using reduced computational time. Additionally, the application of tests with random data enabled the analysis of both the effect of varying parameters in the solution, which provides managerial insights, and the overall performance of the method.

2025

RENEWABLE ENERGY MANAGEMENT SYSTEMS - METHODOLOGICAL ASPECTS FOR ACTIVE POWER CONTROL

Autores
Viegas, P; Bairrão, D; Gonçalves, L; Pereira, JC; Carvalho, LM; SimÕes, J; Silva, P; Dias, S;

Publicação
IET Conference Proceedings

Abstract
A Renewable Energy Management System (REMS) is designed to enhance the operation and efficiency of renewable energy assets, such as wind and solar power, by addressing their inherent variability. Through integration with Supervisory Control and Data Acquisition (SCADA) systems, REMS facilitates real-time adjustments and forecast-based decisions, enabling grid security, optimizing energy dispatch, and maximizing economic benefits. This paper introduces a versatile active power control methodology for renewable energy plants, capable of operating across various time scales to address technical and market-driven requirements. The proposed framework processes inputs from power system measurements to generate forecasts using two distinct approaches, optimizing setpoints for energy dispatch and control processes. Four optimization methods—merit order, weighted allocation, proportional allocation, and linear optimization—are employed to maximize power utilization while adhering to system constraints. The approach is validated for two control intervals: 4 seconds, representing rapid response for converter-based resources, and 15 minutes, simulating broader operational adjustments for reserve provision programs. This dynamic and scalable control framework demonstrates its potential to enhance the management, efficiency, and sustainability of renewable energy systems. © The Institution of Engineering & Technology 2025.

2025

Exploring the Potential of LLM-based Chatbots for Task Scheduling in Robot Operations

Autores
Rema, C; Sousa, A; Sobreira, H; Costa, P; Silva, MF;

Publicação
2025 IEEE INTERNATIONAL CONFERENCE ON AUTONOMOUS ROBOT SYSTEMS AND COMPETITIONS, ICARSC

Abstract
The rise of Industry 4.0 has revolutionized manufacturing by integrating real-time data analysis, artificial intelligence (AI), automation, and interconnected systems, enabling adaptive and resilient smart factories. Autonomous Mobile Robots (AMRs), with their advanced mobility and navigation capabilities, are a pillar of this transformation. However, their deployment in job shop environments adds complexity to the already challenging Job Shop Scheduling Problem (JSSP), expanding it to include task allocation, robot scheduling, and travel time optimization, creating a multi-faceted, non-deterministic polynomial-time hardness (NP-hard) problem. Traditional approaches such as heuristics, meta-heuristics, and mixed integer linear programming (MILP) are commonly used. Recent AI advancements, particularly large language models (LLM), have shown potential in addressing these scheduling challenges due to significant improvements in reasoning and decision-making from textual data. This paper examines the application of LLM to tackle scheduling complexities in smart job shops with mobile robots. Guided by tailored prompts inserted manually, LLM are employed to generate scheduling solutions, being these compared to an heuristic-based method. The results indicate that LLM currently have limitations in solving complex combinatorial problems, such as task scheduling with mobile robots. Due to issues with consistency and repeatability, they are not yet reliable enough for practical implementation in industrial environments. However, they offer a promising foundation for augmenting traditional approaches in the future.

2025

Trends and Future Paths for Simulation and Agent Based Modelling in Industry 4.0

Autores
Carvalhal, C; Marques, J; Mourão, E; Sousa, T; Santos, S; Varela, L; Bastos, J; Ávila, P; Leal, N; Machado, J;

Publicação
Lecture Notes in Mechanical Engineering

Abstract
In this article it is performed an in-depth literature review of simulation in Industry 4.0. This paper intends to evaluate the use of simulation tools, focusing on its developments in Industry 4.0. In the first part a literature review was executed on the significance of simulation tools, such as Digital Twins, Discrete Event Simulation and Agent-Based Modelling, throughout several fields of study, giving special attention to manufacturing and production. A bibliometric analysis is also performed to understand the growth in number of articles published on simulation in Industry 4.0. Then, two case studies are presented, conveying the effectiveness of Digital Twins and Discrete Event Simulation in assisting process planning and control, and manufacturing automation. A few more case studies are also briefly referred in order to reinforce this point. At the end, a discussion about the future of simulation, its applications and advantages in industry settings is held, finally presenting the final thoughts, predicting an exponential growth in simulation uses, establishing this tool as a pillar of industrial production in the future. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2025.

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