Articles publicats (Matemàtica)
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- ItemOpen AccessA Deep Learning Approach for Image Analysis and Reading Body Weight From Digital Scales in Pigs Farms(IEEE, 2025) Reyes-Reyes, Nicolás A.; Doja, Mihai Catalin; Llagostera Blasco, Pol; Pla Aragonés, Lluís Miquel; González Araya, Marcela CeciliaBody weight is an important measure in fattening farms that allows pig farmers to monitor weight gain, manage feeding, and care for animal health. Traditionally, pig weighing is done directly, i.e. placing one or more pigs at a time on a scale while the total body weight is displayed and recorded. However, this process is labor-intensive, causes stress to the animals, and is highly prone to manual recording errors. Recently, several deep learning-based image analysis methods have emerged to estimate pig body weight, but these only consider the animal’s body characteristics. For this reason, an automatic deep learning-based approach is introduced for reading pig body weight from digital scale images. This reading is done by recognizing the body weight values indicated on the scale screen during the weighing process. For this purpose, convolutional neural network models are developed from scale screen segmentation to scale digit classification used to build the body weight value. The proposed approach is applied and validated in a real case study of fattening pigs from a Spanish company. Computational results showed that our approach read body weight with an average error of 20.2 g for a group of pigs with an average weight of 44 kg, taking less than 50 milliseconds to individually recognize the weight value. Therefore, our approach is reliable to support decisions in pig fattening management and suitable to be embedded into real-time weighing systems and useful too for image annotation purposes.
- ItemOpen AccessA reusable public transport electronic ticket system with fast validation(Springer, 2025) Borges Llorens, Ricard; Sebé Feixas, FrancescThis paper presents an electronic ticket system for public transport which provides reusability in the sense that, after the validation of a ticket, a traveler is enabled to perform a journey which can include a limited number of transfers before an expiration time. The proposal has been designed following a privacy-by-design approach. Travelers are only required to identify themselves if requested to prove possession of a valid ticket by an officer. Otherwise, they can travel without being required to disclose their identity (anonymity). Also, the diverse interactions of a traveler with the system cannot be related to them (unlinkability). The security and privacy requirements are achieved by making use of advanced cryptographic techniques. The system has been simulated and proven to provide running times which make it appropriate for a real deployment. When compared to an existing proposal designed for an equivalent scenario, the reduction in the time required for ticket validation is especially remarkable. In effect, all the use cases with real-time constraints (“Ticket validation”, “Get-in”, and “Get-out”) can be run in less than one second.
- ItemOpen AccessOn the Search for Supersingular Elliptic Curves and Their Applications(MDPI, 2025) Martínez-Díaz, Ismel; Ali, Rashad; Kamran Jamil, MuhammadElliptic curves with the special quality known as supersingularity have gained much popularity in the rapidly developing field of cryptography. The conventional method of employing random search is quite ineffective in finding these curves. This paper analyzes the search of supersingular elliptic curves in the space of curves over 𝔽𝑝2. We show that naive random search is unsuitable to easily find any supersingular elliptic curves when the space size is greater than 1013. We improve the random search using a necessary condition for supersingularity. As our main result, we define for the first time an objective function to measure the supersingularity in ordinary curves, and we apply local search and a genetic algorithm using that function. The study not only finds these supersingular elliptic curves but also investigates possible uses for them. These curves were used to create cycles inside the isogeny graph in one particular application. The research shows how the design of S-boxes may strategically use these supersingular elliptic curves. The key components of replacement, which is a fundamental step in the encryption process that shuffles and encrypts the data inside images, are S-boxes. This work represents a major advancement in effectively identifying these useful elliptic curves, eventually leading to their wider application and influence in the rapidly expanding field of cryptography.
- ItemEmbargoDulac functions and monodromic singularities(Elsevier, 2025-02-02) García, I. A. (Isaac A.); Giné, Jaume; Rodero, Ana LiviaWe are interested in bound the maximum number of small amplitude limit cycles that an analytic planar vector field can have bifurcating from any monodromic singularity as well as its stability and hyperbolic nature. We do not use the Poincaré map approach to this problem. Instead, we propose an algorithmic procedure to construct, under some assumptions, a Dulac function in a neighborhood (may be punctured) of the singularity. This approach is based on the existence of a real analytic invariant curve passing through the singularity which allows us to overcome the usual difficulty seeking for the candidates to be a Dulac function. We finally apply our results to a degenerate polynomial monodromic family.
- ItemOpen AccessMonodromic singularities without curves of zero angular speed(AIMS Press, 2025-01-20) García, I. A. (Isaac A.); Giné, JaumeWe consider planar analytic vector fields X having a monodromic singular point with Poincare map ´ Π. We use the fact that there always exists a real analytic invariant curve F = 0 of X in a neighborhood of that singularity. We find some relations between Π and F that can be used to determine new conditions that guarantee the analyticity of Π at the singularity. In the special case that F becomes an inverse integrating factor of X, we rediscover formulas obtained previously by other methods. Applications to the center-focus problem and also to vector fields with degenerate infinity are given.