The FacetedDBLP logo    Search for: in:

Disable automatic phrases ?     Syntactic query expansion: ?

Publications of "Alberto Fernández" ( http://dblp.L3S.de/Authors/Alberto_Fernández )

  Author page on DBLP  Author page in RDF  Community of Alberto Fernández in ASPL-2

Publication years (Num. hits)
2002-2006 (17) 2007-2008 (19) 2009 (15) 2010-2011 (20) 2012 (4)
Publication types (Num. hits)
article(32) inproceedings(43)
Venues (Conferences, Journals, ...)
GrowBag graphs for keyword ? (Num. hits/coverage)

Group by:
The graphs summarize 52 occurrences of 36 keywords

Results
Found 75 publication records. Showing 75 according to the selection in the facets
Hits ? Authors Title Venue Year Link Author keywords
1Victoria López, Alberto Fernández, Jose G. Moreno-Torres, Francisco Herrera Analysis of preprocessing vs. cost-sensitive learning for imbalanced classification. Open problems on intrinsic data characteristics. Search on Bibsonomy Expert Syst. Appl. The full citation details ... 2012 DBLP  DOI  BibTeX  RDF
1Sergio Gomez, Alberto Fernandez, Justo Montiel, David Torres MultiDendrograms: Variable-Group Agglomerative Hierarchical Clustering Search on Bibsonomy CoRR The full citation details ... 2012 DBLP  BibTeX  RDF
1Alberto Fernández, Zijie Cong, Analay Baltá Bridging the gap between service description models in service matchmaking. Search on Bibsonomy Multiagent and Grid Systems The full citation details ... 2012 DBLP  DOI  BibTeX  RDF
1Victoria López, Alberto Fernández, María José del Jesús, Francisco Herrera Cost Sensitive and Preprocessing for Classification with Imbalanced Data-sets: Similar Behaviour and Potential Hybridizations. Search on Bibsonomy ICPRAM The full citation details ... 2012 DBLP  BibTeX  RDF
1Alberto Fernández, Sascha Ossowski A Multiagent Approach to the Dynamic Enactment of Semantic Transportation Services. Search on Bibsonomy IEEE Transactions on Intelligent Transportation Systems The full citation details ... 2011 DBLP  DOI  BibTeX  RDF
1Julián Luengo, Alberto Fernández, Salvador García, Francisco Herrera Addressing data complexity for imbalanced data sets: analysis of SMOTE-based oversampling and evolutionary undersampling. Search on Bibsonomy Soft Comput. The full citation details ... 2011 DBLP  DOI  BibTeX  RDF
1Jürgen Dunkel, Alberto Fernández, Rubén Ortiz, Sascha Ossowski Event-driven architecture for decision support in traffic management systems. Search on Bibsonomy Expert Syst. Appl. The full citation details ... 2011 DBLP  DOI  BibTeX  RDF
1Holger Billhardt, Roberto Centeno, Carlos E. Cuesta, Alberto Fernández, Ramón Hermoso, Rubén Ortiz, Sascha Ossowski, J. Santiago Pérez-Sotelo, Matteo Vasirani Organisational structures in next-generation distributed systems: Towards a technology of agreement. Search on Bibsonomy Multiagent and Grid Systems The full citation details ... 2011 DBLP  DOI  BibTeX  RDF
1Jesús Alcalá-Fdez, Alberto Fernández, Julián Luengo, Joaquín Derrac, Salvador García KEEL Data-Mining Software Tool: Data Set Repository, Integration of Algorithms and Experimental Analysis Framework. Search on Bibsonomy Multiple-Valued Logic and Soft Computing The full citation details ... 2011 DBLP  BibTeX  RDF
1Josean Sanz, Alberto Fernández, Humberto Bustince Sola, Francisco Herrera A genetic tuning to improve the performance of Fuzzy Rule-Based Classification Systems with Interval-Valued Fuzzy Sets: Degree of ignorance and lateral position. Search on Bibsonomy Int. J. Approx. Reasoning The full citation details ... 2011 DBLP  DOI  BibTeX  RDF
1Mikel Galar, Alberto Fernández, Edurne Barrenechea Tartas, Humberto Bustince Sola, Francisco Herrera An overview of ensemble methods for binary classifiers in multi-class problems: Experimental study on one-vs-one and one-vs-all schemes. Search on Bibsonomy Pattern Recognition The full citation details ... 2011 DBLP  DOI  BibTeX  RDF
1Alberto Fernández, Salvador García, Francisco Herrera Addressing the Classification with Imbalanced Data: Open Problems and New Challenges on Class Distribution. Search on Bibsonomy HAIS The full citation details ... 2011 DBLP  DOI  BibTeX  RDF
1Pedro Villar, Alberto Fernández, Francisco Herrera Studying the behavior of a multiobjective genetic algorithm to design fuzzy rule-based classification systems for imbalanced data-sets. Search on Bibsonomy FUZZ-IEEE The full citation details ... 2011 DBLP  DOI  BibTeX  RDF
1José Antonio Sanz, Humberto Bustince Sola, Alberto Fernández, Francisco Herrera On the cooperation of interval-valued fuzzy sets and genetic tuning to improve the performance of fuzzy decision trees. Search on Bibsonomy FUZZ-IEEE The full citation details ... 2011 DBLP  DOI  BibTeX  RDF
1José Antonio Sanz, Alberto Fernández, Humberto Bustince Sola, Francisco Herrera Improving the performance of fuzzy rule-based classification systems with interval-valued fuzzy sets and genetic amplitude tuning. Search on Bibsonomy Inf. Sci. The full citation details ... 2010 DBLP  DOI  BibTeX  RDF
1Salvador García, Alberto Fernández, Julián Luengo, Francisco Herrera Advanced nonparametric tests for multiple comparisons in the design of experiments in computational intelligence and data mining: Experimental analysis of power. Search on Bibsonomy Inf. Sci. The full citation details ... 2010 DBLP  DOI  BibTeX  RDF
1Alberto Fernández, María José del Jesús, Francisco Herrera On the 2-tuples based genetic tuning performance for fuzzy rule based classification systems in imbalanced data-sets. Search on Bibsonomy Inf. Sci. The full citation details ... 2010 DBLP  DOI  BibTeX  RDF
1Alberto Fernández, Salvador García, Julián Luengo, Ester Bernadó-Mansilla, Francisco Herrera Genetics-Based Machine Learning for Rule Induction: State of the Art, Taxonomy, and Comparative Study. Search on Bibsonomy IEEE Trans. Evolutionary Computation The full citation details ... 2010 DBLP  DOI  BibTeX  RDF
1Alberto Fernández, María Calderón, Edurne Barrenechea Tartas, Humberto Bustince Sola, Francisco Herrera Solving multi-class problems with linguistic fuzzy rule based classification systems based on pairwise learning and preference relations. Search on Bibsonomy Fuzzy Sets and Systems The full citation details ... 2010 DBLP  DOI  BibTeX  RDF
1M. Dolores Pérez-Godoy, Alberto Fernández, Antonio Jesús Rivera Rivas, María José del Jesús Analysis of an evolutionary RBFN design algorithm, CO2RBFN, for imbalanced data sets. Search on Bibsonomy Pattern Recognition Letters The full citation details ... 2010 DBLP  DOI  BibTeX  RDF
1Victoria López, Alberto Fernández, Francisco Herrera A first approach for cost-sensitive classification with linguistic Genetic Fuzzy Systems in imbalanced data-sets. Search on Bibsonomy ISDA The full citation details ... 2010 DBLP  DOI  BibTeX  RDF
1José Antonio Sanz, Alberto Fernández, Humberto Bustince Sola, Francisco Herrera A genetic algorithm for tuning fuzzy rule-based classification systems with Interval-Valued Fuzzy Sets. Search on Bibsonomy FUZZ-IEEE The full citation details ... 2010 DBLP  DOI  BibTeX  RDF
1Pedro Villar, Alberto Fernández, Francisco Herrera A Genetic Algorithm for Feature Selection and Granularity Learning in Fuzzy Rule-Based Classification Systems for Highly Imbalanced Data-Sets. Search on Bibsonomy IPMU The full citation details ... 2010 DBLP  DOI  BibTeX  RDF
1Alberto Fernández, María José del Jesús, Francisco Herrera Multi-class Imbalanced Data-Sets with Linguistic Fuzzy Rule Based Classification Systems Based on Pairwise Learning. Search on Bibsonomy IPMU The full citation details ... 2010 DBLP  DOI  BibTeX  RDF
1Salvador García, Alberto Fernández, Julián Luengo, Francisco Herrera A study of statistical techniques and performance measures for genetics-based machine learning: accuracy and interpretability. Search on Bibsonomy Soft Comput. The full citation details ... 2009 DBLP  DOI  BibTeX  RDF Non-parametric tests, Cohen’s kappa, Genetic algorithms, Classification, Interpretability, Statistical tests, Genetics-based machine learning
1Salvador García, Alberto Fernández, Francisco Herrera Enhancing the effectiveness and interpretability of decision tree and rule induction classifiers with evolutionary training set selection over imbalanced problems. Search on Bibsonomy Appl. Soft Comput. The full citation details ... 2009 DBLP  DOI  BibTeX  RDF
1Alberto Fernández, María José del Jesús, Francisco Herrera On the influence of an adaptive inference system in fuzzy rule based classification systems for imbalanced data-sets. Search on Bibsonomy Expert Syst. Appl. The full citation details ... 2009 DBLP  DOI  BibTeX  RDF
1Alberto Fernández, María José del Jesús, Francisco Herrera Hierarchical fuzzy rule based classification systems with genetic rule selection for imbalanced data-sets. Search on Bibsonomy Int. J. Approx. Reasoning The full citation details ... 2009 DBLP  DOI  BibTeX  RDF
1Jürgen Dunkel, Alberto Fernández, Rubén Ortiz, Sascha Ossowski Injecting Semantics into Event-driven Architectures. Search on Bibsonomy ICEIS The full citation details ... 2009 DBLP  BibTeX  RDF
1Josean Sanz, Alberto Fernández, Humberto Bustince Sola, Francisco Herrera A First Study on the Use of Interval-Valued Fuzzy Sets with Genetic Tuning for Classification with Imbalanced Data-Sets. Search on Bibsonomy HAIS The full citation details ... 2009 DBLP  DOI  BibTeX  RDF Genetic Algorithms, Tuning, Imbalanced Data-Sets, Interval-valued Fuzzy Sets, Fuzzy Rule-Based Classification Systems
1Julián Luengo, Alberto Fernández, Salvador García, Francisco Herrera Addressing Data-Complexity for Imbalanced Data-Sets: A Preliminary Study on the Use of Preprocessing for C4.5. Search on Bibsonomy ISDA The full citation details ... 2009 DBLP  DOI  BibTeX  RDF
1Alberto Fernández, Julián Luengo, Joaquín Derrac, Jesús Alcalá-Fdez, Francisco Herrera Implementation and Integration of Algorithms into the KEEL Data-Mining Software Tool. Search on Bibsonomy IDEAL The full citation details ... 2009 DBLP  DOI  BibTeX  RDF Data Mining, Java, Machine Learning, Evolutionary Algorithms, Knowledge Extraction
1Pedro Villar, Alberto Fernández, Francisco Herrera A genetic learning of the fuzzy rule-based classification system granularity for highly imbalanced data-sets. Search on Bibsonomy FUZZ-IEEE The full citation details ... 2009 DBLP  DOI  BibTeX  RDF
1Alberto Fernández, Francisco José Berlanga, María José del Jesús, Francisco Herrera Genetic Cooperative-Competitive Fuzzy Rule Based Learning Method using Genetic Programming for Highly Imbalanced Data-Sets. Search on Bibsonomy IFSA/EUSFLAT Conf. The full citation details ... 2009 DBLP  BibTeX  RDF
1Miguel Rebollo, Adriana Giret, Estefania Argente, Carlos Carrascosa, Juan M. Corchado, Alberto Fernández, Vicente Julián On the Road to an Abstract Architecture for Open Virtual Organizations. Search on Bibsonomy IWANN The full citation details ... 2009 DBLP  DOI  BibTeX  RDF
1Alberto Fernández, María José del Jesús, Francisco Herrera Improving the Performance of Fuzzy Rule Based Classification Systems for Highly Imbalanced Data-Sets Using an Evolutionary Adaptive Inference System. Search on Bibsonomy IWANN The full citation details ... 2009 DBLP  DOI  BibTeX  RDF Parametric Conjunction Operators, Imbalanced Data-Sets, Genetic Fuzzy Systems, Inference System, Fuzzy Rule-Based Classification Systems
1Sara Rodríguez, Alberto Fernández, Vicente Julián, Juan M. Corchado, Sascha Ossowski, Vicente J. Botti THOMAS-MALL: A Multiagent System for Shopping and Guidance in Malls. Search on Bibsonomy IWANN The full citation details ... 2009 DBLP  DOI  BibTeX  RDF
1M. Dolores Pérez-Godoy, Antonio Jesús Rivera Rivas, Alberto Fernández, María José del Jesús, Francisco Herrera A Preliminar Analysis of CO2RBFN in Imbalanced Problems. Search on Bibsonomy IWANN The full citation details ... 2009 DBLP  DOI  BibTeX  RDF Genetic Algorithms, Neural Networks, Radial Basis Functions, Imbalanced Data-Sets
1Roberto Centeno, Moser Silva Fagundes, Holger Billhardt, Sascha Ossowski, Juan M. Corchado, Vicente Julián, Alberto Fernández An Organisation-Based Multiagent System for Medical Emergency Assistance. Search on Bibsonomy IWANN The full citation details ... 2009 DBLP  DOI  BibTeX  RDF
1Javier Escudero, Roberto Hornero, Jesús Poza, Daniel E. Abásolo, Alberto Fernández Assessment of classification improvement in patients with Alzheimer's disease based on magnetoencephalogram blind source separation. Search on Bibsonomy Artificial Intelligence in Medicine The full citation details ... 2008 DBLP  DOI  BibTeX  RDF
1Alberto Fernández, Sergio Gómez Solving Non-Uniqueness in Agglomerative Hierarchical Clustering Using Multidendrograms. Search on Bibsonomy J. Classification The full citation details ... 2008 DBLP  DOI  BibTeX  RDF Agglomerative methods, Lance and Williams’ formula, Ties in proximity, Cluster analysis, Hierarchical classification
1Alberto Fernández, Salvador García, María José del Jesús, Francisco Herrera A study of the behaviour of linguistic fuzzy rule based classification systems in the framework of imbalanced data-sets. Search on Bibsonomy Fuzzy Sets and Systems The full citation details ... 2008 DBLP  DOI  BibTeX  RDF
1Jesús Poza, Roberto Hornero, Daniel E. Abásolo, Alberto Fernández, Agustín Mayo Evaluation of spectral ratio measures from spontaneous MEG recordings in patients with Alzheimer's disease. Search on Bibsonomy Computer Methods and Programs in Biomedicine The full citation details ... 2008 DBLP  DOI  BibTeX  RDF
1Holger Billhardt, Roberto Centeno, Alberto Fernández, Ramón Hermoso, Rubén Ortiz, Sascha Ossowski, Matteo Vasirani On the Relevance of Organizational Structures for a Technology of Agreement. Search on Bibsonomy OTM Workshops The full citation details ... 2008 DBLP  DOI  BibTeX  RDF
1Alberto Fernández, María José del Jesús, Francisco Herrera A Short Study on the Use of Genetic 2-Tuples Tuning for Fuzzy Rule Based Classification Systems in Imbalanced Data-Sets. Search on Bibsonomy HIS The full citation details ... 2008 DBLP  DOI  BibTeX  RDF Linguistic 2-Tuples Representation, Genetic Algorithms, Tuning, Imbalanced Data-Sets, Genetic Fuzzy Systems, Fuzzy Rule-Based Classification Systems
1Alberto Fernández, Sascha Ossowski Exploiting organisational information for service coordination in multiagent systems. Search on Bibsonomy AAMAS The full citation details ... 2008 DBLP  DOI  BibTeX  RDF
1Alberto Fernández, Conor Hayes, Nikos Loutas, Vassilios Peristeras, Axel Polleres, Konstantinos A. Tarabanis Closing the Service Discovery Gap by Collaborative Tagging and Clustering Techniques. Search on Bibsonomy SMRR The full citation details ... 2008 DBLP  BibTeX  RDF
1Alberto Fernández, Sergio Gómez Portfolio selection using neural networks. Search on Bibsonomy Computers & OR The full citation details ... 2007 DBLP  DOI  BibTeX  RDF
1Alex Arenas, Alberto Fernández, Sergio Gómez Multiple resolution of the modular structure of complex networks Search on Bibsonomy CoRR The full citation details ... 2007 DBLP  BibTeX  RDF
1Carlos Gómez, Roberto Hornero, Daniel E. Abásolo, Alberto Fernández, Javier Escudero Analysis of the magnetoencephalogram background activity in Alzheimer's disease patients with auto-mutual information. Search on Bibsonomy Computer Methods and Programs in Biomedicine The full citation details ... 2007 DBLP  DOI  BibTeX  RDF
1Alberto Fernández, Sascha Ossowski Exploiting Organizational Models for Semantic Service Description, .. Search on Bibsonomy ERCIM News The full citation details ... 2007 DBLP  BibTeX  RDF
1Alberto Fernández, Salvador García, Francisco Herrera, María José del Jesús An Analysis of the Rule Weights and Fuzzy Reasoning Methods for Linguistic Rule Based Classification Systems Applied to Problems with Highly Imbalanced Data Sets. Search on Bibsonomy WILF The full citation details ... 2007 DBLP  DOI  BibTeX  RDF rule weight, Fuzzy Reasoning Method, Imbalanced Data-sets, Over-sampling, Fuzzy Rule Based Classification Systems
1Alex Arenas, Alberto Fernández, Sergio Gómez A Complex Network Approach to the Determination of Functional Groups in the Neural System of C. Elegans. Search on Bibsonomy BIOWIRE The full citation details ... 2007 DBLP  DOI  BibTeX  RDF
1Alberto Fernández, Sascha Ossowski Filters for semantic service composition in service-oriented multiagent systems. Search on Bibsonomy AAMAS The full citation details ... 2007 DBLP  DOI  BibTeX  RDF multiagent systems, service composition, semantic web services
1Alberto Fernández, Axel Polleres, Sascha Ossowski Towards Fine-grained Service Matchmaking by Using Concept Similarity. Search on Bibsonomy SMRR The full citation details ... 2007 DBLP  BibTeX  RDF
1Alberto Fernández, Sascha Ossowski Semantic Service Composition in Service-Oriented Multiagent Systems: A Filtering Approach. Search on Bibsonomy SOCASE The full citation details ... 2007 DBLP  DOI  BibTeX  RDF
1Alberto Fernández, Matteo Vasirani, César Cáceres, Sascha Ossowski A Role-Based Support Mechanism for Service Description and Discovery. Search on Bibsonomy SOCASE The full citation details ... 2007 DBLP  DOI  BibTeX  RDF
1Alberto Fernández, Salvador García, María José del Jesús, Francisco Herrera A Study on the Use of the Fuzzy Reasoning Method Based on the Winning Rule vs. Voting Procedure for Classification with Imbalanced Data Sets. Search on Bibsonomy IWANN The full citation details ... 2007 DBLP  DOI  BibTeX  RDF Fuzzy Reasoning Method, Imbalanced Data-sets, Instance Selection, Over-sampling, Fuzzy Rule Based Classification Systems
1Alberto Fernández, Sergio Gómez Solving non-uniqueness in agglomerative hierarchical clustering using multidendrograms Search on Bibsonomy CoRR The full citation details ... 2006 DBLP  BibTeX  RDF
1César Cáceres, Alberto Fernández, Sascha Ossowski, Matteo Vasirani Agent-Based Semantic Service Discovery for Healthcare: An Organizational Approach. Search on Bibsonomy IEEE Intelligent Systems The full citation details ... 2006 DBLP  DOI  BibTeX  RDF ontology, Semantic Web, artificial intelligence, multiagent systems, healthcare, intelligent Web services
1César Cáceres, Alberto Fernández, Sascha Ossowski, Matteo Vasirani The CASCOM Abstract Architecture for Semantic Service Discovery and Coordination in IP2P Environments. Search on Bibsonomy ICEIS The full citation details ... 2006 DBLP  BibTeX  RDF
1César Cáceres, Alberto Fernández, Sascha Ossowski, Matteo Vasirani An abstract architecture for semantic service coordination in agent-based intelligent peer-to-peer environments. Search on Bibsonomy SAC The full citation details ... 2006 DBLP  DOI  BibTeX  RDF mobile computing, intelligent agents, peer-to-peer computing, service coordination
1Federico Bergenti, César Cáceres, Alberto Fernández, Nadine Fröhlich, Heikki Helin, Oliver Keller, Ari Kinnunen, Matthias Klusch, Heimo Laamanen, António Lopes, Sascha Ossowski, Heiko Schuldt, Michael Schumacher Context-aware Service Coordination for Mobile e-Health Applications. Search on Bibsonomy ECEH The full citation details ... 2006 DBLP  BibTeX  RDF
1Salvador García, José Ramón Cano, Alberto Fernández, Francisco Herrera A Proposal of Evolutionary Prototype Selection for Class Imbalance Problems. Search on Bibsonomy IDEAL The full citation details ... 2006 DBLP  DOI  BibTeX  RDF
1César Cáceres, Alberto Fernández, Sascha Ossowski, Matteo Vasirani An Abstract Architecture for Service Coordination in IP2P Environments. Search on Bibsonomy Computer Supported Acitivity Coordination The full citation details ... 2006 DBLP  BibTeX  RDF
1Alberto Fernández, Matteo Vasirani, César Cáceres, Sascha Ossowski Role-based Service Description and Discovery. Search on Bibsonomy EUMAS The full citation details ... 2006 DBLP  BibTeX  RDF
1Alberto Fernández, Sergio Gómez Portfolio selection using neural networks Search on Bibsonomy CoRR The full citation details ... 2005 DBLP  BibTeX  RDF
1María-Victoria Belmonte, José-Luis Pérez-de-la-Cruz, Francisco Triguero Ruiz, Alberto Fernández Agent coordination for bus fleet management. Search on Bibsonomy SAC The full citation details ... 2005 DBLP  DOI  BibTeX  RDF FIPA interaction protocols, multiagent decision support systems, traffic management, agent coordination
1Alberto Fernández, Sergio Gómez A Hopfield Network for the Portfolio Selection Problem. Search on Bibsonomy CCIA The full citation details ... 2005 DBLP  BibTeX  RDF
1Heikki Helin, Matthias Klusch, António Lopes, Alberto Fernández, Michael Schumacher, Heiko Schuldt, Federico Bergenti, Ari Kinnunen CASCOM: Context-Aware Service Co-ordination in Mobile P2P Environments. Search on Bibsonomy MATES The full citation details ... 2005 DBLP  DOI  BibTeX  RDF
1Sascha Ossowski, Josefa Z. Hernández, María-Victoria Belmonte, José-Manuel Maseda, Alberto Fernández, Ana García-Serrano, Francisco Triguero Ruiz, Juan Manuel Serrano, José-Luis Pérez-de-la-Cruz Multi-Agent Systems For Decision Support: A Case Study In The Transportation Management Domain. Search on Bibsonomy Applied Artificial Intelligence The full citation details ... 2004 DBLP  DOI  BibTeX  RDF
1Sascha Ossowski, Alberto Fernández, Juan Manuel Serrano, José-Luis Pérez-de-la-Cruz, María-Victoria Belmonte, Josefa Z. Hernández, Ana García-Serrano, José-Manuel Maseda Designing Multiagent Decision Support System - The Case of Transportation Management. Search on Bibsonomy AAMAS The full citation details ... 2004 DBLP  DOI  BibTeX  RDF
1Juan Manuel Serrano, Sascha Ossowski, Alberto Fernández The Pragmatics of Software Agents: Analysis and Design of Agent Communication Languages. Search on Bibsonomy AgentLink The full citation details ... 2003 DBLP  DOI  BibTeX  RDF
1Sascha Ossowski, José-Luis Pérez-de-la-Cruz, Josefa Z. Hernández, José-Manuel Maseda, Alberto Fernández, María-Victoria Belmonte, Ana García-Serrano, Juan Manuel Serrano, Rafael León, Francesco Carbone Towards a Generic Multiagent Model for Decision Support: Two Case Studies. Search on Bibsonomy CAEPIA The full citation details ... 2003 DBLP  DOI  BibTeX  RDF
1Sascha Ossowski, Josefa Z. Hernández, Carlos Angel Iglesias, Alberto Fernández Engineering Agent Systems for Decision Support. Search on Bibsonomy ESAW The full citation details ... 2002 DBLP  DOI  BibTeX  RDF
Displaying result #1 - #75 of 75 (100 per page; Change: )
Valid XHTML 1.1! Valid CSS! [Valid RSS]
Maintained by Jörg Diederich.
Based upon DBLP by Michael Ley.