2022
Authors
Araujo, C; Soares, C; Pereira, I; Coelho, D; Rebelo, MA; Madureira, A;
Publication
APPLIED SCIENCES-BASEL
Abstract
In the digital world, the demand for better interactions between subscribers and companies is growing, creating the need for personalized and individualized experiences. With the exponential growth of email usage over the years, broad flows of campaigns are sent and received by subscribers, which reveals itself to be a problem for both companies and subscribers. In this work, subscribers are segmented by their behaviors and profiles, such as (i) open rates, (ii) click-through rates, (iii) frequency, and (iv) period of interactions with the companies. Different regressions are used: (i) Random Forest Regressor, (ii) Multiple Linear Regression, (iii) K-Neighbors Regressor, and (iv) Support Vector Regressor. All these regressions' results were aggregated into a final prediction achieved by an ensemble approach, which uses averaging and stacking methods. The use of Long Short-Term Memory is also considered in the presented case. The stacking model obtained the best performance, with an R-2 score of 0.91 and a Mean Absolute Error of 0.204. This allows us to estimate the week's days with a half-day error difference. This work presents promising results for subscriber segmentation based on profile information for predicting the best period for email marketing. In the future, subscribers can be segmented using the Recency, Frequency and Monetary value, the Lifetime Value, or Stream Clustering approaches that allow more personalized and tailored experiences for subscribers. The latter tracks segments over time without costly recalculations and handles continuous streams of new observations without the necessity to recompile the entire model.
2022
Authors
Coelho, D; Madureira, A; Pereira, I; Gonçalves, R;
Publication
International Journal of Computer Information Systems and Industrial Management Applications
Abstract
In the areas ofmachine learning / big data, when collecting data, sometimes too many features may be stored. Some of them may be redundant or irrelevant for the problem to be solved, adding noise to the dataset. Feature selection allows to create a subset from the original feature set, according to certain criteria. By creating a smaller subset of relevant features, it is possible to improve the learning accuracy while reducing the amount of data. This means means better results obtained in a shorter learning time. However, feature selection is normally regarded as a very important problem to be solved, as it directly impacts both data analysis and model creation. The problem of optimizing the selected features of a given dataset is not always trivial but, throughout the years, different ways to counter this optimization problem have been presented. This work presents how feature selection fits in the larger context of multi-objective problems as well as a review of how both multi-objective evolutionary algorithms and metaheuristics are being used in order to solve feature selection problems © MIR Labs, www.mirlabs.net/ijcisim/index.html
2023
Authors
Sousa, B; Santos, AS; Madureira, AM;
Publication
Lecture Notes in Networks and Systems
Abstract
In this article the influence of the maximum partition size on the performance of a discrete version of the Bat Algorithm (BA) is studied. The Bat Algorithm is a population-based meta-heuristic based on swarm intelligence developed for continuous problems with exceptional results. Thus, it has a set of parameters that must be studied in order to enhance the performance of the meta-heuristic. This paper aims to investigate whether the maximum size of the partitions used for the search operations throughout the algorithm should not also be considered as a parameter. First, a literature review was conducted, with special focus on the parameterization of the meta-heuristics and each of the parameters currently used in the algorithm, followed by its implementation in VBA in Microsoft Excel. After a thorough parameterization of the discrete algorithm, different maximum partition sizes were applied to 30 normally distributed instances to draw broader conclusions. In addition, they were also tested for different sizes of the problem to see if they had an influence on the results obtained. Finally, a statistical analysis was carried out, where it was possible to conclude that there was no maximum partition value for which superiority could be proven, and so the size of the partition should be considered a parameter in the bat algorithm and included in the parametrization of BA. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.
2023
Authors
Mateus, F; Santos, AS; Brito, MF; Madureira, AM;
Publication
Lecture Notes in Networks and Systems
Abstract
The transport and logistics sector, which include freight forwarders companies, constitutes a vast network of entities that are central to a good performance in services. With the COVID-19 pandemic and its effects on the global economy, there was a huge shortage in the number of containers available, thus creating the need to optimize the loading of available equipment to avoid waste and maximize profits from each export. The present work presents a novel approach where a set of restrictions were created that, applied in synergy with the Non-Linear GRG algorithm, aim to allocate the boxes in different consecutive lines until forming a wall, and, therefore, the walls complete the container, in order to maximize the occupancy on it. To validate the proposed approach a prototype was developed and studied in real-world problem where the solutions resulted in occupations around 80% to 90%. Thus, we can foresee the importance of the proposed approach in decision-making regarding container consolidation services. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.
2023
Authors
Antal, L; Aubard, M; Ábrahám, E; Madureira, A; Madureira, L; Costa, M; Pinto, J; Campos, R;
Publication
Lecture Notes in Networks and Systems
Abstract
Over the past decades, underwater robotics has enjoyed growing popularity and relevance. While performing a mission, one crucial task for Autonomous Underwater Vehicles (AUVs) is bottom tracking, which should keep a constant distance from the seabed. Since static obstacles like walls, rocks, or shipwrecks can lie on the sea bottom, bottom tracking needs to be extended with obstacle avoidance. As AUVs face a wide range of uncertainties, implementing these essential operations is still challenging. A simple rule-based control method has been proposed in [7] to realize obstacle avoidance. In this work, we propose an alternative AI-based control method using a Long Short-Term Memory network. We compare the performance of both methods using real-world data as well as via a simulator. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.
2023
Authors
Cunha, B; Madureira, A; Gonçalves, L;
Publication
Lecture Notes in Networks and Systems
Abstract
Multiple Sclerosis is one of the most common diseases of the central nervous system that affects millions of people worldwide. The prediction of this disease is considered a challenge since the symptoms are highly variable as the disease worsens and, as such, it has emerged as a topic that artificial intelligence scientists have tried to challenge. With the goal of providing a brief review that may serve as a starting point for future researchers on such a deep field, this paper puts forward a summary of artificial intelligence applications for Multiple Sclerosis evaluation and diagnosis. It includes a detailed recap of what Multiple Sclerosis is, the connections between artificial intelligence and the human brain, and a description of the main proposals in this field. It also concludes what the most reliable methods are at the present time, discussing approaches that achieve accuracy values up to 98.8%. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.
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