Iker Pastor López

Dr. Iker Pastor López

orcid

Research Focus & Metrics

Academic Career Length

15Years (2012-Present)

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

Representative Publications

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7 October 2023 in Neurocomputing
Verified
Journal Article
Closed access
AMAlberto Miranda-García
Alberto Miranda-García
ARAgustín Zubillaga Rego
Agustín Zubillaga Rego
Iker Pastor LópezIker Pastor López
Iker Pastor López
BSBorja Sanz
Borja Sanz
Alberto Tellaeche IglesiasAlberto Tellaeche Iglesias
Alberto Tellaeche Iglesias
Pablo Garcia-BringasPablo Garcia-Bringas
Pablo Garcia-Bringas

29 January 2024 in IEEE Access
Verified
Journal Article
Open access
DCDaniel González Cortés
Daniel González Cortés
Enrique OnievaEnrique Onieva
Enrique Onieva
Iker Pastor LópezIker Pastor López
Iker Pastor López
LTLaura Trinchera
Laura Trinchera
JWJian Wu
Jian Wu
While Machine Learning significantly boosts the performance of predictive models, its efficacy varies across different data dimensions. It is essential to cluster time series data of similar characteristics, particularly in the financial sector. However, clustering financial time series data poses considerable challenges due to the market’s inherent complexity and multidimensionality. To address these issues, our study introduces a novel clustering framework that leverages autoencoders for a compressed yet informative representation of financial time series. We rigorously evaluate our approach through multiple dimensionality reduction and clustering algorithms, applying it to key financial indices, including IBEX-35, CAC-40, DAX-30, S&P 500, and FTSE 100. Our findings consistently demonstrate that incorporating autoencoders significantly enhances the granularity and quality of clustering, effectively isolating distinct categories of financial time series. Our findings carry significant ramifications for the financial industry. By refining clustering methodologies, we set the stage for increasingly accurate financial predictive models, offering valuable insights for optimizing investment strategies and enhancing risk management.

11 May 2021 in Sensors
Verified
Journal Article
Open access
PDF file
Alberto Tellaeche IglesiasAlberto Tellaeche Iglesias
Alberto Tellaeche Iglesias
MAMiguel Ángel Campos Anaya
Miguel Ángel Campos Anaya
Gonzalo Pajares MartinsanzGonzalo Pajares Martinsanz
Gonzalo Pajares Martinsanz
Iker Pastor LópezIker Pastor López
Iker Pastor López
Defects in textured materials present a great variability, usually requiring ad-hoc solutions for each specific case. This research work proposes a solution that combines two machine learning-based approaches, convolutional autoencoders, CA; one class support vector machines, SVM. Both methods are trained using only defect free textured images for each type of analyzed texture, labeling the samples for the SVMs in an automatic way. This work is based on two image processing streams using image sensors: (1) the CA first processes the incoming image from the input to the output, producing a reconstructed image, from which a measurement of correct or defective image is obtained; (2) the second process uses the latent layer information as input to the SVM to produce a measurement of classification. Both measurements are effectively combined, making an additional research contribution. The results obtained achieve a percentage of success of 92% on average, outperforming results of previous works.

Verified
Journal Article
Open access
PDF file
XSXabier Sarrionandia
Xabier Sarrionandia
Javier NievesJavier Nieves
Javier Nieves
Beñat Bravo ZubillagaBeñat Bravo Zubillaga
Beñat Bravo Zubillaga
Iker Pastor LópezIker Pastor López
Iker Pastor López
Pablo Garcia-BringasPablo Garcia-Bringas
Pablo Garcia-Bringas
Metallographic analyses of nodular iron casting methods are based on visual comparisons according to measuring standards. Specifically, the microstructure is analyzed in a subjective manner by comparing the extracted image from the microscope to pre-defined image templates. The achieved classifications can be confused, due to the fact that the features extracted by a human being could be interpreted differently depending on many variables, such as the conditions of the observer. In particular, this kind of problem represents an uncertainty when classifying metallic properties, which can influence the integrity of castings that play critical roles in safety devices or structures. Although there are existing solutions working with extracted images and applying some computer vision techniques to manage the measurements of the microstructure, those results are not too accurate. In fact, they are not able to characterize all specific features of the image and, they cannot be adapted to several characterization methods depending on the specific regulation or customer. Hence, in order to solve this problem, we propose a framework to improve and automatize the evaluations by combining classical machine vision techniques for feature extraction and deep learning technologies, to objectively make classifications. To adapt to the real analysis environments, all included inputs in our models were gathered directly from the historical repository of metallurgy from the Azterlan Research Centre (labeled using expert knowledge from engineers). The proposed approach concludes that these techniques (a classification under a pipeline of deep neural networks and the quality classification using an ANN classifier) are viable to carry out the extraction and classification of metallographic features with great accuracy and time, and it is possible to deploy software with the models to work on real-time situations. Moreover, this method provides a direct way to classify the metallurgical quality of the molten metal, allowing us to determine the possible behaviors of the final produced parts.

26 August 2019
Verified
Book Chapter
Closed access
PDF file
Iker Pastor LópezIker Pastor López
Iker Pastor López
BSBorja Sanz
Borja Sanz
JPJosé Gaviria de la Puerta
José Gaviria de la Puerta
PBPablo G. Bringas
Pablo G. Bringas

2 July 2024 in Expert Systems
Verified
Journal Article
Open access
DCDaniel González Cortés
Daniel González Cortés
Enrique OnievaEnrique Onieva
Enrique Onieva
Iker Pastor LópezIker Pastor López
Iker Pastor López
LTLaura Trinchera
Laura Trinchera
JWJian Wu
Jian Wu
While machine learning's role in financial trading has advanced considerably, algorithmic transparency and explainability challenges still exist. This research enriches prior studies focused on high‐frequency financial data prediction by introducing an explainable reinforcement learning model for portfolio management. This model transcends basic asset prediction, formulating concrete, actionable trading strategies. The methodology is applied in a custom trading environment mimicking the CAC‐40 index's financial conditions, allowing the model to adapt dynamically to market changes based on iterative learning from historical data. Empirical findings reveal that the model outperforms an equally weighted portfolio in out‐of‐sample tests. The study offers a dual contribution: it elevates algorithmic planning while significantly boosting transparency and interpretability in financial machine learning. This approach tackles the enduring ‘black‐box’ issue and provides a holistic, transparent framework for managing investment portfolios.