Álvar Arnaiz-González

Dr. Álvar Arnaiz-González

orcid

Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

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

Representative Publications

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25 September 2023 in ISA Transactions
Verified
Journal Article
Open access
José Miguel Ramírez-SanzJosé Miguel Ramírez-Sanz
José Miguel Ramírez-Sanz
JMJose-Alberto Maestro-Prieto
Jose-Alberto Maestro-Prieto
ÁAÁlvar Arnaiz-González
Álvar Arnaiz-González
ABAndres Bustillo
Andres Bustillo
The automation of Fault Detection and Diagnosis (FDD) is a central task for many industries today. A myriad of methods are in use, although the most recent leading contenders are data-driven approaches and especially Machine Learning (ML) methods. ML algorithms fall into two main categories: supervised and unsupervised methods, depending on whether or not the instances are labeled with the expected outputs. However, a new approach called Semi-Supervised Learning (SSL) has recently emerged that uses a few labeled instances together with other unlabeled instances for the training process. This new approach can significantly improve the accuracy of conventional ML models for industrial environments where labeled data are scarce. SSL has been tested as a promising solution over the past few years for several FDD problems, although there have been no systemic reviews of this sort of approach up until the present review. In this study, an attempt to organize the existing literature on SSL for FDD using the taxonomy of van Engelen & Hoos is reported. The most and the least frequently used SSL algorithms are identified and considered in terms of different fault detection tasks and their most common dataset structure. Moreover, a set of best practices are proposed in the conclusions of this work for implementation under real industrial conditions, so as to avoid some of the most common faults.

MARIA CONSUELO SAIZ MANZANARESMARIA CONSUELO SAIZ MANZANARES
MARIA CONSUELO SAIZ MANZANARES
MEMARÍA DEL CAMINO ESCOLAR-LLAMAZARES
MARÍA DEL CAMINO ESCOLAR-LLAMAZARES
ÁAÁlvar Arnaiz-González
Álvar Arnaiz-González
Currently, teaching in higher education is being heavily developed by learning management systems that record the learning behaviour of both students and teachers. The use of learning management systems that include project-based learning and hypermedia resources increases safer learning, and it is proven to be effective in degrees such as nursing. In this study, we worked with 120 students in the third year of nursing degree. Two types of blended learning were applied (more interaction in learning management systems with hypermedia resources vs. none). Supervised learning techniques were applied: linear regression and k-means clustering. The results indicated that the type of blended learning in use predicted 40.4% of student learning outcomes. It also predicted 71.9% of the effective learning behaviors of students in learning management systems. It therefore appears that blended learning applied in Learning Management System (LMS) with hypermedia resources favors greater achievement of effective learning. Likewise, with this type of Blended Learning (BL) a larger number of students were found to belong to the intermediate cluster, suggesting that this environment strengthens better results in a larger number of students. BL with hypermedia resources and project-based learning increase students´ learning outcomes and interaction in learning management systems. Future research will be aimed at verifying these results in other nursing degree courses.

1 August 2015 in The International Journal of Advanced Manufacturing Technology
Verified
Journal Article
Closed access
PDF file
ÁAÁlvar Arnaiz-González
Álvar Arnaiz-González
AFAsier Fernández-Valdivielso
Asier Fernández-Valdivielso
ABAndres Bustillo
Andres Bustillo
Luis Norberto López De LacalleLuis Norberto López De Lacalle
Luis Norberto López De Lacalle

1 September 2016 in Knowledge-Based Systems
Verified
Journal Article
Open access
ÁAÁlvar Arnaiz-González
Álvar Arnaiz-González
JDJosé-Francisco Díez-Pastor
José-Francisco Díez-Pastor
JRJuan J. Rodriguez
Juan J. Rodriguez
César García-OsorioCésar García-Osorio
César García-Osorio
Over recent decades, database sizes have grown considerably. Larger sizes present new challenges, because machine learning algorithms are not prepared to process such large volumes of information. Instance selection methods can alleviate this problem when the size of the data set is medium to large. However, even these methods face similar problems with very large-to-massive data sets.\ud \ud In this paper, two new algorithms with linear complexity for instance selection purposes are presented. Both algorithms use locality-sensitive hashing to find similarities between instances. While the complexity of conventional methods (usually quadratic, O(n2), or log-linear, O(nlogn)) means that they are unable to process large-sized data sets, the new proposal shows competitive results in terms of accuracy. Even more remarkably, it shortens execution time, as the proposal manages to reduce complexity and make it linear with respect to the data set size. The new proposal has been compared with some of the best known instance selection methods for testing and has also been evaluated on large data sets (up to a million instances).Supported by the Research Projects TIN 2011-24046 and TIN 2015-67534-P from the Spanish Ministry of Economy and Competitiveness

1 April 2020 in Knowledge-Based Systems
Verified
Journal Article
Closed access
JRJuan J. Rodriguez
Juan J. Rodriguez
JDJosé-Francisco Díez-Pastor
José-Francisco Díez-Pastor
ÁAÁlvar Arnaiz-González
Álvar Arnaiz-González
LKLudmila I. Kuncheva
Ludmila I. Kuncheva

1 July 2016 in Information Fusion
Verified
Journal Article
Closed access
ÁAÁlvar Arnaiz-González
Álvar Arnaiz-González
Marcin BlachnikMarcin Blachnik
Marcin Blachnik
MKMiroslaw Kordos
Miroslaw Kordos
César García-OsorioCésar García-Osorio
César García-Osorio