Examinando por Autor "Rojas, K"

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Consistency and stability in aggregation operators with data structure
(2013 Joint IFSA World Congress and NAFIPS Annual Meeting (IFSA/NAFIPS), 2013) Rojas, K; Gómez, D; Rodríguez, JT; Montero, J
In this work, we continue with a previous work in which we analyzed and defined notions of consistency, stability and continuity of a family of aggregation operators (FAO) when the data is unstructured. Here we use these concepts to tackle with aggregation problem for those situations in which the information or data that has to be aggregated has an inherent structure. In particular, we will focus on two structures that has received an important attention during last decades due to it application is different fields as Muticriteria Decision Analysis: The linear order structures and the hierarchical structures from a prioritized point of view.
Consistency and stability in aggregation operators: an application to missing data problems
(Aggregation Functions in Theory and in Practise: Proceedings of the 7th International Summer School on Aggregation Operators at the Public University of Navarra, Pamplona, Spain, July 16-20, 2013, 2013) Gómez, D; Rojas, K; Montero, J; Rodríguez, JT
An aggregation operator is usually defined as a real function A n such that, from n data items x 1, …, x n in [0,1], produces an aggregated value A n (x 1,…,x n ) in [0,1]. This definition can be extended to consider the whole family of operators for any n instead of a single operator for an specific n. This has led to the current standard definition [4, 15] of a family of aggregation operators (FAO) as a set {A n :[0,1]n → [0,1],n ∈ N}, providing instructions on how to aggregate collections of items of any dimension n. This sequence of aggregation functions {A n } n ∈ N is also called extended aggregation functions (EAF) by other authors.
Development of child's home environment indexes based on consistent families of aggregation operators with prioritized hierarchical information
(Fuzzy Sets and Systems, 2013-06-24) Rojas, K; Gómez, D; Montero, J; Rodríguez, JT
The interventions aimed at the early childhood are of a main interest in educational policy, since it is in this period when it is possible to produce a major impact in the subsequent human development. The quality of children's social environment is the main influence to consider in achieving sound child development, affecting throughout school life. For this reason, the development of child's environment indexes appears in a natural way in the evaluation of all kind of educational policy research and social programs. However, crisp measures and indexes, based on usual linear techniques, do not ensure an adequate representation of social reality, since this last has a fuzzy nature and a nonlinear behavior. The development of indexes can be seen as an aggregation problem. In this paper, we extend the notions of consistency and strict stability of a family of aggregation operators (FAO), proposed in a previous work of the authors for the case of an aggregation process in which the data have no particular structure, to the case in which the information has a prioritized hierarchical structure. This extended notion of strict stability is then used to address the construction of indexes. Particularly, we apply this approach to develop a construction method of child's home environment indexes in which a stable family of prioritized aggregation operators is used in order to ensure robustness of the aggregation process when the information has a lineal structure. These indexes are built using fuzzy data that fit into a hierarchical structure by means of a stable family of prioritized aggregation operators based on the prioritized operator formulated by Yager, where the order relationship over fuzzy information was defined by experts on child development.
Some properties of consistency in the families of aggregation operators
(Eurofuse 2011: Workshop on Fuzzy Methods for Knowledge-Based Systems, 2012) Rojas, K; Gómez, Daniel; Montero, J; Rodríguez, JT
Aggregation functions have been widely studied in literature. Nevertheless, few efforts have been dedicated to analyze those properties related with the family of operators in a global way. In this work, we analyze the stability in a family of aggregation operators The stability property for a family of aggregation operators tries to force a family to have a stable/continuous definition in the sense that the aggregation of n − 1 items should be similar to the aggregation of n items if the last item is the aggregation of the previous n − 1 items. Following this idea some definitions and results are given.
Stability in Aggregation Operators
(Advances in Computational Intelligence. IPMU 2012. Communications in Computer and Information Science, 2012) Rojas, K; Gómez, D; Montero, J; Rodríguez, JT
Aggregation functions have been widely studied in literature. Nevertheless, few efforts have been dedicated to analyze those properties related with the family of operators in a global way. In this work, we analyze the stability in a family of aggregation operators The stability property for a family of aggregation operators tries to force a family to have a stable/continuous definition in the sense that the aggregation of n − 1 items should be similar to the aggregation of n items if the last item is the aggregation of the previous n − 1 items. Following this idea some definitions and results are given.
Strictly stable families of aggregation operators
(Fuzzy Sets and Systems, 2013) Rojas, K; Gómez, D; Rodríguez, JT; Montero, J
In this paper we analyze the notion of family of aggregation operators (FAO), also refereed to as extended aggregation functions (EAF), i.e., a set of aggregation operators defined in the unit interval which aggregate several input values into a single output value. In particular, we address the key issue of the relationship that should hold between the operators in a family in order to understand that they properly define a consistent FAO. We focus on the idea of strict stability of a family of aggregation operators in order to propose an operative notion of consistency between operators of such a family. In this way, robustness of the aggregation process can be guaranteed. Some strict stability definitions for FAOs are proposed, leading to a classification of the main aggregation operators in terms of the properties they satisfy. Furthermore, we apply this approach to analyze the stability of some families of aggregation operators based on weights.