Adrián Valledor

Mr. Adrián Valledor

orcid

Research Focus & Metrics

Academic Career Length

4Years (2023-Present)

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

Representative Publications

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24 September 2023 in Sustainability
Verified
Journal Article
Open access
PDF file
CHCarlos J. Hellín
Carlos J. Hellín
FCFrancisco Calles-Esteban
Francisco Calles-Esteban
AVAdrián Valledor
Adrián Valledor
JGJosé Gómez-Pulido
José Gómez-Pulido
SALVADOR OTON TORTOSASALVADOR OTON TORTOSA
SALVADOR OTON TORTOSA
Abdelhamid TayebiAbdelhamid Tayebi
Abdelhamid Tayebi
Gamification is a viable strategy used to enhance motivation and engagement in programming classes among students. However, automated evaluation capabilities, which are crucial for giving students fast and correct feedback, are frequently lacking in currently available gamification technologies. This study proposes a novel web-based application that combines automated programming assessment features with gamification concepts; the aim is to provide students taking a programming course with an engaging learning environment. A survey conducted with 215 undergraduate students assessed how the tool affected the motivation and engagement of students. The findings show that the tool had a beneficial impact on students’ willingness to participate in class, study, increase their self-confidence, engage in healthy competition with peers, and learn from their mistakes. The qualitative feedback that students offered regarding the features of the tool that they liked best is also covered in the study. This paper contributes to the field of programming education by presenting a detailed gamified tool, incorporating automated evaluation and gamification in a web-based platform.

18 April 2024 in Applied Sciences
Verified
Journal Article
Open access
PDF file
CHCarlos J. Hellín
Carlos J. Hellín
ARAlvaro Antonio Olmedo Rodriguez
Alvaro Antonio Olmedo Rodriguez
AVAdrián Valledor
Adrián Valledor
JGJosé Gómez-Pulido
José Gómez-Pulido
MLMiguel López-Benítez
Miguel López-Benítez
Abdelhamid TayebiAbdelhamid Tayebi
Abdelhamid Tayebi
The field of image analysis with artificial intelligence has grown exponentially thanks to the development of neural networks. One of its most promising areas is medical diagnosis through lung X-rays, which are crucial for diseases like pneumonia, which can be mistaken for other conditions. Despite medical expertise, precise diagnosis is challenging, and this is where well-trained algorithms can assist. However, working with medical images presents challenges, especially when datasets are limited and unbalanced. Strategies to balance these classes have been explored, but understanding their local impact and how they affect model evaluation is still lacking. This work aims to analyze how a class imbalance in a dataset can significantly influence the informativeness of metrics used to evaluate predictions. It demonstrates that class separation in a dataset impacts trained models and is a strategy deserving more attention in future research. To achieve these goals, classification models using artificial and deep neural networks implemented in the R environment are developed. These models are trained using a set of publicly available images related to lung pathologies. All results are validated using metrics obtained from the confusion matrix to verify the impact of data imbalance on the performance of medical diagnostic models. The results raise questions about the procedures used to group classes in many studies, aiming to achieve class balance in imbalanced data and open new avenues for future research to investigate the impact of class separation in datasets with clinical pathologies.

3 August 2023 in Sustainability
Verified
Journal Article
Open access
PDF file
AVAdrián Valledor
Adrián Valledor
ARAlvaro Antonio Olmedo Rodriguez
Alvaro Antonio Olmedo Rodriguez
CHCarlos J. Hellín
Carlos J. Hellín
Abdelhamid TayebiAbdelhamid Tayebi
Abdelhamid Tayebi
SALVADOR OTON TORTOSASALVADOR OTON TORTOSA
SALVADOR OTON TORTOSA
JGJosé Gómez-Pulido
José Gómez-Pulido
This paper proposes a study of the methodologies used to teach English as a second language through computer applications. It reviews the different methodologies used in language teaching in order to contrast them with different fundamental approaches. It examines the applications used for teaching English online, especially those in line with personalised learning environments and learner-centred autonomy. The use of a mixed methodology is reported, allowing the selection of papers from both a traditional systematic review and the search engine elicit.org. Finally, it is concluded that Blended Learning is the most appropriate method, highlighting that current applications are mainly based on the Audio-Lingual method, which limits their practical use in wider contexts. Further research is needed on software applications that prioritise personalised learning environments with learner-centred autonomy, incorporating technologies based on Blended Learning and artificial intelligence (AI). To this end, it is proposed in the future to develop an application using Automatic Speech Recognition (ASR), Text To Speech (TTS), Natural Language Understanding (NLU) and Dialog Management (DM) algorithms, focusing on the above and simulating the capabilities of a teacher. This may lead to innovations in the development of software applications capable of integrating different methods, teaching modalities and learning methods.

14 July 2023 in Sensors
Verified
Journal Article
Open access
PDF file
JGJosé Gómez-Pulido
José Gómez-Pulido
Abdelhamid TayebiAbdelhamid Tayebi
Abdelhamid Tayebi
CHCarlos J. Hellín
Carlos J. Hellín
AVAdrián Valledor
Adrián Valledor
MBMarcos Barranquero
Marcos Barranquero
JCJuan J. Cuadrado-Gallego
Juan J. Cuadrado-Gallego
The implementation of a fast and efficient computer tool for field coverage studies in urban mobile radio systems is presented in this work. An accelerated and tailored ray launching method takes advantage of a ray tracing programmable framework optimized for massively parallel processing on GPUs. The PlotOptiX API is used to customize the code before applying the electromagnetic equations. The proposed code is described, and results are shown to demonstrate its correct operation. A high number of diffractions and reflections can be tracked in each ray from the transmitter to the receiver. In addition to the typical point-to-point simulation, measurement planes can also be set as receivers to provide fast predictions in wide urban areas.

28 March 2024 in Sensors
Verified
Journal Article
Open access
PDF file
FCFrancisco Calles-Esteban
Francisco Calles-Esteban
ARAlvaro Antonio Olmedo Rodriguez
Alvaro Antonio Olmedo Rodriguez
CHCarlos J. Hellín
Carlos J. Hellín
AVAdrián Valledor
Adrián Valledor
JGJosé Gómez-Pulido
José Gómez-Pulido
Abdelhamid TayebiAbdelhamid Tayebi
Abdelhamid Tayebi
The precise placement of antennas is essential to ensure effective coverage, service quality, and network capacity in wireless communications, particularly given the exponential growth of mobile connectivity. The antenna positioning problem (APP) has evolved from theoretical approaches to practical solutions employing advanced algorithms, such as evolutionary algorithms. This study focuses on developing innovative web tools harnessing genetic algorithms to optimize antenna positioning, starting from propagation loss calculations. To achieve this, seven empirical models were reviewed and integrated into an antenna positioning web tool. Results demonstrate that, with minimal configuration and careful model selection, a detailed analysis of antenna positioning in any area is feasible. The tool was developed using Java 17 and TypeScript 5.1.6, utilizing the JMetal framework to apply genetic algorithms, and features a React-based web interface facilitating application integration. For future research, consideration is given to implementing a server capable of analyzing the environment based on specific area selection, thereby enhancing the precision and objectivity of antenna positioning analysis.

31 August 2023 in IEEE Access
Verified
Journal Article
Open access
CHCarlos J. Hellín
Carlos J. Hellín
AVAdrián Valledor
Adrián Valledor
LULuis Usero
Luis Usero
JCJuan J. Cuadrado-Gallego
Juan J. Cuadrado-Gallego
Abdelhamid TayebiAbdelhamid Tayebi
Abdelhamid Tayebi
JGJosé Gómez-Pulido
José Gómez-Pulido
The term Text Mining , which is given to the set of techniques used for the extraction, cleaning and processing of the information in texts, has become useful to provide valuable information to other algorithms and widely used with statistical and machine learning methods. By enabling the extraction of useful insights from textual data, Text Mining has become a potent tool in decision-making and knowledge discovery across many areas, including health care, government, education and industry. R is a mature open-source programming environment that has overstepped its initial scope of application for statistical computing and graphics to be used in pretty all the Data Science knowledge Area Groups. The objective of this paper is to present review and benchmarking analysis of packages for text mining techniques with R in computational systems. The paper reviews thirteen different packages comparing them on their execution time and memory used, for which new tests have been specifically designed. The results of this approach have been intended to be used over the most common tasks carried out when analyzing texts, and comparisons included allow R users to know which packages are best for each task and to improve their performance. Text mining package (tm) stands out particularly in Tokenization and Stemming techniques, while fastTextR is the best choice for Topic Modeling and Normalization. Also in the case of the Term Frequency–Inverse Document Frequency (TF-IDF) technique, the textir package is a clear choice. The other packages will depend on whether the technique is applied to a document-term matrix (DTM) or to plain text. In addition, there are packages that perform better in runtime than in memory usage and vice versa, making the choice more difficult. Packages such as udpipe can achieve better results working in parallel. Future works will include the same analysis for parallel computing, hybrid approaches, and novel algorithms.