Rafael Magdalena

Dr. Rafael Magdalena

orcid

Research Focus & Metrics

Academic Career Length

20Years (2007-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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10 April 2020 in Physical Review Letters
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Journal Article
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YDYongcheng Ding
Yongcheng Ding
José D.José D.
José D.
MSMikel Sanz
Mikel Sanz
RMRafael Magdalena
Rafael Magdalena
Xi ChenXi Chen
Xi Chen
ESEnrique Solano
Enrique Solano
Active learning is a machine learning method aiming at optimal design for model training. At variance with supervised learning, which labels all samples, active learning provides an improved model by labeling samples with maximal uncertainty according to the estimation model. Here, we propose the use of active learning for efficient quantum information retrieval, which is a crucial task in the design of quantum experiments. Meanwhile, when dealing with large data output, we employ active learning for the sake of classification with minimal cost in fidelity loss. Indeed, labeling only 5% samples, we achieve almost 90% rate estimation. The introduction of active learning methods in the data analysis of quantum experiments will enhance applications of quantum technologies.

13 April 2022 in Acta Psychiatrica Scandinavica
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JSJoan Vicent Sánchez‐Ortí
Joan Vicent Sánchez‐Ortí
Vicent Balanzá-MartínezVicent Balanzá-Martínez
Vicent Balanzá-Martínez
PGPatricia Correa Ghisays
Patricia Correa Ghisays
GVGabriel Vera
Gabriel Vera
Joan Vila-FrancésJoan Vila-Francés
Joan Vila-Francés
RTRafael Tabarés-Seisdedos
Rafael Tabarés-Seisdedos
Objective: Obesity and metabolic diseases such as metabolic syndrome (MetS) are more prevalent in people with type 2 diabetes mellitus (T2DM), major depressive disorder (MDD), bipolar disorder (BD), and schizophrenia (SZ). MetS components might be associated with neurocognitive and functional impairments in these individuals. The predictive and discriminatory validity of MetS and its components regarding those outcomes were assessed from prospective and transdiagnostic perspectives.Methods: Metabolic syndrome components and neurocognitive and social functioning were assessed in 165 subjects, including 30 with SZ, 42 with BD, 35 with MDD, 30 with T2DM, and 28 healthy controls (HCs). A posteriori, individuals were classified into two groups. The MetS group consisted of those who met at least three of the following criteria: abdominal obesity (AO), elevated triglycerides (TG), reduced high‐density lipoprotein cholesterol (HDL), elevated blood pressure (BP), and elevated fasting glucose (FPG); the remaining participants comprised the No‐MetS group. Mixed one‐way analysis of covariance and linear and binary logistic regression analyses were performed.Results: Cognitive impairment was significantly greater in the MetS group (n = 82) than in the No‐MetS group (n = 83), with small effect sizes (p < 0.05; η²p = 0.02 – 0.03). In both groups, the most robust associations between MetS components and neurocognitive and social functioning were observed with TG and FPG (p < 0.05). There was also evidence for a significant relationship between cognition and BP in the MetS group (p < 0.05). The combination of TG, FPG, elevated systolic BP and HDL best classified individuals with greater cognitive impairment (p < 0.001), and TG was the most accurate (p < 0.0001).Conclusions: Specific MetS components are significantly associated with cognitive impairment across somatic and psychiatric disorders. Our findings provide further evidence on the summative effect of MetS components to predict cognition and social functioning and allow the identification of individuals with worse outcomes. Transdiagnostic, lifestyle‐based therapeutic interventions targeted at that group hold the potential to improve health outcomes.

26 February 2025 in Information
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AHAntonio Herreros-Martínez
Antonio Herreros-Martínez
RMRafael Magdalena
Rafael Magdalena
Joan Vila-FrancésJoan Vila-Francés
Joan Vila-Francés
Antonio-José Serrano-LópezAntonio-José Serrano-López
Antonio-José Serrano-López
Sonia Pérez-DíazSonia Pérez-Díaz
Sonia Pérez-Díaz
José Javier Martínez HerraizJosé Javier Martínez Herraiz
José Javier Martínez Herraiz
In the era of increasing digitalisation, organisations face the critical challenge of detecting anomalies in large volumes of data, which may indicate suspicious activities. To address this challenge, audit engagements are conducted regularly, and internal auditors and purchasing specialists seek innovative methods to streamline these processes. This study introduces a methodology to prioritise the investigation of anomalies identified in two large real-world purchase datasets. The primary objective is to enhance the effectiveness of companies’ control efforts and improve the efficiency of anomaly detection tasks. The approach begins with a comprehensive exploratory data analysis, followed by the application of unsupervised machine learning techniques to identify anomalies. A univariate analysis is performed using the z-Score index and the DBSCAN algorithm, while multivariate analysis employs k-Means clustering and Isolation Forest algorithms. Additionally, the Silhouette index is used to evaluate the quality of the clustering, ensuring each method produces a prioritised list of candidate transactions for further review. To refine this process, an ensemble prioritisation framework is developed, integrating multiple methods. Furthermore, explainability tools such as SHAP are utilised to provide actionable insights and support specialists in interpreting the results. This methodology aims to empower organisations to detect anomalies more effectively and streamline the audit process.

5 February 2007 in IEEE Transactions on Education
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Journal Article
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JGJUAN GUERRERO
JUAN GUERRERO
MBManuel Bataller
Manuel Bataller
ESEmilio Soria
Emilio Soria
RMRafael Magdalena
Rafael Magdalena
This paper introduces and evaluates BioLab, a tool for teaching biosignal processing. BioLab has been used in the biomedical engineering module that is given in the second semester of the fifth year of the electronic engineering degree at the University of Valencia, Spain. This module and its correspondent curricular pathway are also reviewed. BioLab allows the results obtained with digital processing techniques to be shown interactively in the theory classes, and it also provides support in laboratory sessions. The graphic interface of BioLab simplifies its learning and use and provides access to processing and visualization functions by means of menus. The tool is based on Matlab since the students have had previous experience in this environment. BioLab also supports diverse formats of data files, which facilitate access to real records and their conversion to usable formats. The modular structure of BioLab allows it to be easily extended to other educational materials that are related to signal processing and to research applications. An evaluation of BioLab has revealed that students found it useful for understanding the general concepts of digital processing and biosignal processing in particular. The students also found BioLab very easy to learn and use

28 November 2024 in Applied Sciences
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ARAlejandro Dionis Ros
Alejandro Dionis Ros
Joan Vila-FrancésJoan Vila-Francés
Joan Vila-Francés
RMRafael Magdalena
Rafael Magdalena
Fernando Mateo JiménezFernando Mateo Jiménez
Fernando Mateo Jiménez
Antonio-José Serrano-LópezAntonio-José Serrano-López
Antonio-José Serrano-López
In this article, we propose the detection of crowd anomalies through the extraction of information in the form of time series in video format using a multimodal approach. Through pattern recognition algorithms and segmentation, informative measures of the number of people and image occupancy are extracted at regular intervals, which are then analyzed to obtain trends and anomalous behaviors. Specifically, through temporal decomposition and residual analysis, intervals or specific situations of unusual behaviors are identified, which can be used in decision-making and the improvement of actions in sectors related to human movement such as tourism or security. This methodology introduces a novel, privacy-focused approach by analyzing anonymized metrics rather than tracking or recognizing individuals, setting a new standard for ethical crowd monitoring. Applied to the webcam of Turisme Comunitat Valenciana in the town of Morella (Comunitat Valenciana, Spain), this approach has shown excellent results, correctly detecting specific anomalous situations and unusual overall increases during the previous weekend and during the October 2023 festivities. These results have been obtained while preserving the confidentiality of individuals at all times by using measures that maximize anonymity, without trajectory recording or person recognition.

21 March 2022 in Physical Review Research
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Journal Article
Open access
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YDYongcheng Ding
Yongcheng Ding
José D.José D.
José D.
YSYujing Song
Yujing Song
RMRafael Magdalena
Rafael Magdalena
Xi ChenXi Chen
Xi Chen
Optimal design for model training is a critical topic in machine learning. Active learning aims at obtaining improved models by querying samples with maximum uncertainty according to the estimation model for artificially labeling; this has the additional advantage of achieving successful performances with a reduced number of labeled samples. We analyze its capability as an assistant for the design of experiments, extracting maximum information for learning with the minimal cost in fidelity loss, or reducing total operation costs of labeling in the laboratory. We present two typical applications as quantum information retrieval in qutrits and phase boundary prediction in many-body physics. For an equivalent multinomial classification problem, we achieve the correct rate of 99% with less than 2% of samples labeled. We reckon that active-learning-inspired physics experiments will remarkably save budget without loss of accuracy.