As it is known the Web is changing the information access processes. The Web is one of the most i... more As it is known the Web is changing the information access processes. The Web is one of the most important information media. Furthermore, the Web is influencing in the development of other information media, as for example, newspapers, journals, books, libraries, etc. In this chapter we analyze its impact in the development of the University Digital Libraries (UDL). As in the Web, the growing of information is the main problem of the academic digital libraries, and similar tools could be applied in university digital libraries to facilitate the information access to the students and teachers. Filtering systems or recommender systems are tools whose objective is to evaluate and filter the great amount of information available on the Web to assist the users in their information access processes. Therefore, we present a model of fuzzy linguistic recommender system to help students and researchers to find research resources which could improve the services that render the UDL to their users.
In the resolution of group decision making problems where the consensus process can not be held f... more In the resolution of group decision making problems where the consensus process can not be held face to face by the experts it is usually difficult for them to be able to identify the closeness of the opinions of the rest of the experts, and thus, it is difficult to have a clear view of the current state of the consensus process. In this paper we present a tool that creates consensus diagrams that can help experts to easily comprehend the current consensus state and to easily identify the experts that have similar or very different opinions. Those diagrams are based on several new similarity and consistency measures.
International Journal of Intelligent Systems, 2004
In this paper we introduce the Induced Ordered Weighted Geometric (IOWG) operator and its propert... more In this paper we introduce the Induced Ordered Weighted Geometric (IOWG) operator and its properties. This is a more general type of Ordered Weighted Geometric operator which is based on the Induced Ordered Weighted Averaging operator defined by Yager and Filev. We provide some IOWG operators to aggregate multiplicative preference relations in group decision-making problems. In particular, we present the Importance Induced Ordered Weighted Geometric (I-IOWG) operator, which induces the ordering of the argument values based upon the importance of the information sources; the Consistency Induced Ordered Weighted Geometric (C-IOWG) operator, which induces the ordering of the argument values based upon the consistency of the information sources; and the Preference Induced Ordered Weighted Geometric (P-IOWG) operator, which induces the ordering of the argument values based upon the relative preference values associated to each one of them. We also provide a procedure to deal with 'ties' in respect of the ordering induced by the application of one of these IOWG operators. This procedure consists of a sequential application of the above IOWG operators. Finally, we analyse the reciprocity and consistency properties of the collective multiplicative preference relations obtained using IOWG operators.
Un Sistema De Recomendaciones Linguístico Difuso Para Filtrar Recursos en Bibliotecas Digitales Universitarias
Resumen—En este trabajo se presenta el diseño de un sistema de recomendaciones lingüístico difuso... more Resumen—En este trabajo se presenta el diseño de un sistema de recomendaciones lingüístico difuso para facilitar a los alumnos el acceso a información sobre recursos docentes que puedan ser de su interés. Al sugerir material didáctico adecuado a las necesidades específicas del alumno, se fomenta un aprendizaje significativo, incidiendo directamente en el proceso de enseñanza- aprendizaje. El uso de dicho
An ordinal fuzzy linguistic Information Retrieval System (IRS) based on a multi-level weighting s... more An ordinal fuzzy linguistic Information Retrieval System (IRS) based on a multi-level weighting scheme to represent the user queries, in a more flexible way, is proposed. The IRS accepts Boolean queries that can be weighted simultaneously by means of ordinal linguistic values in two weighting levels: level of terms and level of connectives. In level of terms, the weights are associated to a threshold semantics, and in the level of connectives they are associated to a control semantics acting as modifiers of the action of the Boolean classical connectives AND and OR in the retrieval process. A new family of parameterized soft computing operators, called S-LOWA operators, is introduced for modelling that control semantics in the action of the connectives AND and OR.
To be able to measure the scientific output of researchers is an increasingly important task to s... more To be able to measure the scientific output of researchers is an increasingly important task to support research assessment decisions. To do so, we can find several different measures and indices in the literature. Recently, the h-index, introduced by Hirsch in 2005, has got a lot of attention from the scientific community for its good properties to measure the scientific production of researchers. Additionally, several different indicators, for example, the g-index, have been developed to try to improve the possible drawbacks of the h-index. In this paper we present a new index, called hg-index, to characterize the scientific output of researchers which is based on both h-index and g-index to try to keep the advantages of both measures as well as to minimize their disadvantages.
Fuzzy Optimization and Decision Making, Sep 17, 2009
Computing with Words (CW) methodology has been used in several different environments to narrow t... more Computing with Words (CW) methodology has been used in several different environments to narrow the differences between human reasoning and computing. As Decision Making is a typical human mental process, it seems natural to apply the CW methodology in order to create and enrich decision models in which the information that is provided and manipulated has a qualitative nature. In this paper we make a review of the developments of CW in decision making. We begin with an overview of the CW methodology and we explore different linguistic computational models that have been applied to the decision making field. Then we present an historical perspective of CW in decision making by examining the pioneer papers in the field along with its most recent applications. Finally, some current trends, open questions and prospects in the topic are pointed out.
2007 Ieee International Fuzzy Systems Conference, Jun 1, 2007
The consistency of reciprocal preference relations is studied. Consistency is related with ration... more The consistency of reciprocal preference relations is studied. Consistency is related with rationality, which is associated with the transitivity property. For fuzzy preference relations many properties have been suggested to model transitivity and, consequently, consistency may be measured according to which of these different properties is required to be satisfied. However, we will show that many of them are not appropriate for reciprocal preference relations. We put forward a functional equation to model consistency of reciprocal preference relations, and show that self-dual uninorms operators are the solutions to it. In particular, Tanino's multiplicative transitivity property being an example of such type of uninorms seems to be an appropriate consistency property for fuzzy reciprocal preferences.
Some induced ordered weighted averaging operators and their use for solving group decision-making problems based on fuzzy preference relations
In [RR Yager, DP Filev, Operations for granular computing: Mixing words and numbers, in: Proceedi... more In [RR Yager, DP Filev, Operations for granular computing: Mixing words and numbers, in: Proceedings of the FUZZ-IEEE World Congress on Computational Intelligence, Anchorage, 1998, pp. 123–128] Yager and Filev introduced the Induced Ordered Weighted Averaging (IOWA) operator. In this paper, we provide some IOWA operators to aggregate fuzzy preference relations in group decision-making (GDM) problems. These IOWA operators when guided by fuzzy linguistic quantifiers allow the introduction of some semantics or ...
Consistency of preferences is related to rationality, which is associated with the transitivity p... more Consistency of preferences is related to rationality, which is associated with the transitivity property. Many properties suggested to model transitivity of preferences are inappropriate for reciprocal preference relations. In this paper, a functional equation is put forward to model the "cardinal consistency in the strength of preferences" of reciprocal preference relations. We show that under the assumptions of continuity and monotonicity properties, the set of representable uninorm operators is characterized as the solution to this functional equation. Cardinal consistency with the conjunctive representable cross ratio uninorm is equivalent to Tanino's multiplicative transitivity property. Because any two representable uninorms are order isomorphic, we conclude that multiplicative transitivity is the most appropriate property for modeling cardinal consistency of reciprocal preference relations. Results toward the characterization of this uninorm consistency property based on a restricted set of (n − 1) preference values, which can be used in practical cases to construct perfect consistent preference relations, are also presented.
Journal of Multiple Valued Logic and Soft Computing, 2008
To achieve consistent solutions is an important goal in group decision making problems. However, ... more To achieve consistent solutions is an important goal in group decision making problems. However, the expression of preferences is often a very difficult task for the experts, specially in decision problems with a high number of alternatives and when experts use fuzzy preference relations to provide their opinions. This usually leads to situations where experts are not able to properly express all their preferences in a consistent way, that is, without contradiction. In this paper, to overcome this problem, we present a decision support system based on consistency criteria to aid experts to express their fuzzy preference relations in a more consistent way. The system works interactively with the expert by providing him/her recommendations on the preference values that he/she has not yet expressed. These recommendations are computed trying to maintain the expert's consistency level as high as possible.
In group decision making (GDM) processes, prior to the selection of the best alternative(s), it w... more In group decision making (GDM) processes, prior to the selection of the best alternative(s), it would be desirable that experts achieve a high degree of consensus or agreement between them. Due to the complexity of most decision making problems, individuals' preferences may not satisfy formal properties. 'Consistency' is one of such properties, and it is associated with the transitivity property. Obviously, when carrying out a rational decision making, consistent information, i.e. information which does not imply any kind of contradiction, is more appropriate than information containing some contradictions. Therefore, in a GDM process, consistency should also be sought after. In this paper we present a consensus model for GDM problems that proceeds from consistency to consensus. This model includes a novel consistency reaching module based on consistency measures. In particular, the model generates advice on how experts should change their preferences in order to reach a solution with high consistency and consensus degrees.
Intelligent Decision Making Systems - Proceedings of the 4th International ISKE Conference on Intelligent Systems and Knowledge Engineering, 2010
Web 2.0 technologies provide rich and lightweight online tools that let users contribute new data... more Web 2.0 technologies provide rich and lightweight online tools that let users contribute new data. They can associate in social networks, share ideas and information and collaborate together for many kind of reasons, obtaining a community's "collective intelligence". We propose to compute this collective intelligence with a Mobile Decision Support System (MDSS) to aggregate recommendations and use this collective advice to improve the customer satisfaction in decision making situations related with the m-commerce activities.
Applied Artificial Intelligence - Proceedings of the 7th International FLINS Conference, 2006
In Group Decision Making, the expression of preferences is often a very difficult task for the ex... more In Group Decision Making, the expression of preferences is often a very difficult task for the experts, specially in decision problems with a high number of alternatives. The problem is increased when they are asked to give their preferences in form of preference relations: although preference relations have a very high level of expresivity and they present good properties that allow to operate with them easily, the amount of preference values that the experts are required to give increases exponentially. This usually leads to situations where the expert is not capable of properly express all his/her preferences in a consistent way (that is, without contradiction), so finally the information provided can easily be either inconsistent or incomplete (when the expert prefers not to give some particular preference values). In this work we develop a support system, based on some transitivity properties, to aid experts to express their preferences (in form of preference relations) in a more consistent way. The system works interactively with the expert making recomendations for the preference values that the expert have not yet expressed. Those recomendations are computed trying to maintain the consistency level of the expert as high as possible.
Web 2.0 Communities allow large amounts of users to interact with each others. In fact, new Web 2... more Web 2.0 Communities allow large amounts of users to interact with each others. In fact, new Web 2.0 technologies allow to share resources and information in an easy and timely manner, allowing real time communication among persons all over the world. However, as Web 2.0 Communities are a quite recent phenomenon with its own characteristics and particularities, there is still a necessity of developing new tools that allow to reach decisions with a high enough consensus level among their users. In this contribution we present a new consensus reaching model designed to incorporate the benefits that a Web 2.0 Community offers (rich and diverse knowledge due to a large number of users, real-time communication.. .) and that tries to minimize the main problems that this kind of organization presents (low and intermittent participation rates, difficulty of establishing trust relations and so on).
IEEE Transactions on Systems, Man, and Cybernetics: Systems, 2014
In the literature, we find that the consensus models proposed for group decision making problems ... more In the literature, we find that the consensus models proposed for group decision making problems are guided by consensus degrees and/or similarity measures and/or consistency measures [1]. When we work in heterogeneous group decision making frameworks, we have importance degrees associated with the experts by expressing their different knowledge levels on the problem. Usually, the importance degrees are applied in the weighted aggregation operators developed to solve the decision situations. In this paper, we study another application possibility, i.e., to use heterogeneity existing among experts to guide the consensus model. Thus, the main goal of this paper is to present a new consensus model for heterogeneous group decision making problems guided also by the heterogeneity criterion. It is also based on consensus degrees and similarity measures, but it presents a new feedback mechanism that adjusts the amount of advice required by each expert depending on his/her own relevance or importance level.
As it is known the Web is changing the information access processes. The Web is one of the most i... more As it is known the Web is changing the information access processes. The Web is one of the most important information media. Furthermore, the Web is influencing in the development of other information media, as for example, newspapers, journals, books, libraries, etc. In this chapter we analyze its impact in the development of the University Digital Libraries (UDL). As in the Web, the growing of information is the main problem of the academic digital libraries, and similar tools could be applied in university digital libraries to facilitate the information access to the students and teachers. Filtering systems or recommender systems are tools whose objective is to evaluate and filter the great amount of information available on the Web to assist the users in their information access processes. Therefore, we present a model of fuzzy linguistic recommender system to help students and researchers to find research resources which could improve the services that render the UDL to their users.
In the resolution of group decision making problems where the consensus process can not be held f... more In the resolution of group decision making problems where the consensus process can not be held face to face by the experts it is usually difficult for them to be able to identify the closeness of the opinions of the rest of the experts, and thus, it is difficult to have a clear view of the current state of the consensus process. In this paper we present a tool that creates consensus diagrams that can help experts to easily comprehend the current consensus state and to easily identify the experts that have similar or very different opinions. Those diagrams are based on several new similarity and consistency measures.
International Journal of Intelligent Systems, 2004
In this paper we introduce the Induced Ordered Weighted Geometric (IOWG) operator and its propert... more In this paper we introduce the Induced Ordered Weighted Geometric (IOWG) operator and its properties. This is a more general type of Ordered Weighted Geometric operator which is based on the Induced Ordered Weighted Averaging operator defined by Yager and Filev. We provide some IOWG operators to aggregate multiplicative preference relations in group decision-making problems. In particular, we present the Importance Induced Ordered Weighted Geometric (I-IOWG) operator, which induces the ordering of the argument values based upon the importance of the information sources; the Consistency Induced Ordered Weighted Geometric (C-IOWG) operator, which induces the ordering of the argument values based upon the consistency of the information sources; and the Preference Induced Ordered Weighted Geometric (P-IOWG) operator, which induces the ordering of the argument values based upon the relative preference values associated to each one of them. We also provide a procedure to deal with 'ties' in respect of the ordering induced by the application of one of these IOWG operators. This procedure consists of a sequential application of the above IOWG operators. Finally, we analyse the reciprocity and consistency properties of the collective multiplicative preference relations obtained using IOWG operators.
Un Sistema De Recomendaciones Linguístico Difuso Para Filtrar Recursos en Bibliotecas Digitales Universitarias
Resumen—En este trabajo se presenta el diseño de un sistema de recomendaciones lingüístico difuso... more Resumen—En este trabajo se presenta el diseño de un sistema de recomendaciones lingüístico difuso para facilitar a los alumnos el acceso a información sobre recursos docentes que puedan ser de su interés. Al sugerir material didáctico adecuado a las necesidades específicas del alumno, se fomenta un aprendizaje significativo, incidiendo directamente en el proceso de enseñanza- aprendizaje. El uso de dicho
An ordinal fuzzy linguistic Information Retrieval System (IRS) based on a multi-level weighting s... more An ordinal fuzzy linguistic Information Retrieval System (IRS) based on a multi-level weighting scheme to represent the user queries, in a more flexible way, is proposed. The IRS accepts Boolean queries that can be weighted simultaneously by means of ordinal linguistic values in two weighting levels: level of terms and level of connectives. In level of terms, the weights are associated to a threshold semantics, and in the level of connectives they are associated to a control semantics acting as modifiers of the action of the Boolean classical connectives AND and OR in the retrieval process. A new family of parameterized soft computing operators, called S-LOWA operators, is introduced for modelling that control semantics in the action of the connectives AND and OR.
To be able to measure the scientific output of researchers is an increasingly important task to s... more To be able to measure the scientific output of researchers is an increasingly important task to support research assessment decisions. To do so, we can find several different measures and indices in the literature. Recently, the h-index, introduced by Hirsch in 2005, has got a lot of attention from the scientific community for its good properties to measure the scientific production of researchers. Additionally, several different indicators, for example, the g-index, have been developed to try to improve the possible drawbacks of the h-index. In this paper we present a new index, called hg-index, to characterize the scientific output of researchers which is based on both h-index and g-index to try to keep the advantages of both measures as well as to minimize their disadvantages.
Fuzzy Optimization and Decision Making, Sep 17, 2009
Computing with Words (CW) methodology has been used in several different environments to narrow t... more Computing with Words (CW) methodology has been used in several different environments to narrow the differences between human reasoning and computing. As Decision Making is a typical human mental process, it seems natural to apply the CW methodology in order to create and enrich decision models in which the information that is provided and manipulated has a qualitative nature. In this paper we make a review of the developments of CW in decision making. We begin with an overview of the CW methodology and we explore different linguistic computational models that have been applied to the decision making field. Then we present an historical perspective of CW in decision making by examining the pioneer papers in the field along with its most recent applications. Finally, some current trends, open questions and prospects in the topic are pointed out.
2007 Ieee International Fuzzy Systems Conference, Jun 1, 2007
The consistency of reciprocal preference relations is studied. Consistency is related with ration... more The consistency of reciprocal preference relations is studied. Consistency is related with rationality, which is associated with the transitivity property. For fuzzy preference relations many properties have been suggested to model transitivity and, consequently, consistency may be measured according to which of these different properties is required to be satisfied. However, we will show that many of them are not appropriate for reciprocal preference relations. We put forward a functional equation to model consistency of reciprocal preference relations, and show that self-dual uninorms operators are the solutions to it. In particular, Tanino's multiplicative transitivity property being an example of such type of uninorms seems to be an appropriate consistency property for fuzzy reciprocal preferences.
Some induced ordered weighted averaging operators and their use for solving group decision-making problems based on fuzzy preference relations
In [RR Yager, DP Filev, Operations for granular computing: Mixing words and numbers, in: Proceedi... more In [RR Yager, DP Filev, Operations for granular computing: Mixing words and numbers, in: Proceedings of the FUZZ-IEEE World Congress on Computational Intelligence, Anchorage, 1998, pp. 123–128] Yager and Filev introduced the Induced Ordered Weighted Averaging (IOWA) operator. In this paper, we provide some IOWA operators to aggregate fuzzy preference relations in group decision-making (GDM) problems. These IOWA operators when guided by fuzzy linguistic quantifiers allow the introduction of some semantics or ...
Consistency of preferences is related to rationality, which is associated with the transitivity p... more Consistency of preferences is related to rationality, which is associated with the transitivity property. Many properties suggested to model transitivity of preferences are inappropriate for reciprocal preference relations. In this paper, a functional equation is put forward to model the "cardinal consistency in the strength of preferences" of reciprocal preference relations. We show that under the assumptions of continuity and monotonicity properties, the set of representable uninorm operators is characterized as the solution to this functional equation. Cardinal consistency with the conjunctive representable cross ratio uninorm is equivalent to Tanino's multiplicative transitivity property. Because any two representable uninorms are order isomorphic, we conclude that multiplicative transitivity is the most appropriate property for modeling cardinal consistency of reciprocal preference relations. Results toward the characterization of this uninorm consistency property based on a restricted set of (n − 1) preference values, which can be used in practical cases to construct perfect consistent preference relations, are also presented.
Journal of Multiple Valued Logic and Soft Computing, 2008
To achieve consistent solutions is an important goal in group decision making problems. However, ... more To achieve consistent solutions is an important goal in group decision making problems. However, the expression of preferences is often a very difficult task for the experts, specially in decision problems with a high number of alternatives and when experts use fuzzy preference relations to provide their opinions. This usually leads to situations where experts are not able to properly express all their preferences in a consistent way, that is, without contradiction. In this paper, to overcome this problem, we present a decision support system based on consistency criteria to aid experts to express their fuzzy preference relations in a more consistent way. The system works interactively with the expert by providing him/her recommendations on the preference values that he/she has not yet expressed. These recommendations are computed trying to maintain the expert's consistency level as high as possible.
In group decision making (GDM) processes, prior to the selection of the best alternative(s), it w... more In group decision making (GDM) processes, prior to the selection of the best alternative(s), it would be desirable that experts achieve a high degree of consensus or agreement between them. Due to the complexity of most decision making problems, individuals' preferences may not satisfy formal properties. 'Consistency' is one of such properties, and it is associated with the transitivity property. Obviously, when carrying out a rational decision making, consistent information, i.e. information which does not imply any kind of contradiction, is more appropriate than information containing some contradictions. Therefore, in a GDM process, consistency should also be sought after. In this paper we present a consensus model for GDM problems that proceeds from consistency to consensus. This model includes a novel consistency reaching module based on consistency measures. In particular, the model generates advice on how experts should change their preferences in order to reach a solution with high consistency and consensus degrees.
Intelligent Decision Making Systems - Proceedings of the 4th International ISKE Conference on Intelligent Systems and Knowledge Engineering, 2010
Web 2.0 technologies provide rich and lightweight online tools that let users contribute new data... more Web 2.0 technologies provide rich and lightweight online tools that let users contribute new data. They can associate in social networks, share ideas and information and collaborate together for many kind of reasons, obtaining a community's "collective intelligence". We propose to compute this collective intelligence with a Mobile Decision Support System (MDSS) to aggregate recommendations and use this collective advice to improve the customer satisfaction in decision making situations related with the m-commerce activities.
Applied Artificial Intelligence - Proceedings of the 7th International FLINS Conference, 2006
In Group Decision Making, the expression of preferences is often a very difficult task for the ex... more In Group Decision Making, the expression of preferences is often a very difficult task for the experts, specially in decision problems with a high number of alternatives. The problem is increased when they are asked to give their preferences in form of preference relations: although preference relations have a very high level of expresivity and they present good properties that allow to operate with them easily, the amount of preference values that the experts are required to give increases exponentially. This usually leads to situations where the expert is not capable of properly express all his/her preferences in a consistent way (that is, without contradiction), so finally the information provided can easily be either inconsistent or incomplete (when the expert prefers not to give some particular preference values). In this work we develop a support system, based on some transitivity properties, to aid experts to express their preferences (in form of preference relations) in a more consistent way. The system works interactively with the expert making recomendations for the preference values that the expert have not yet expressed. Those recomendations are computed trying to maintain the consistency level of the expert as high as possible.
Web 2.0 Communities allow large amounts of users to interact with each others. In fact, new Web 2... more Web 2.0 Communities allow large amounts of users to interact with each others. In fact, new Web 2.0 technologies allow to share resources and information in an easy and timely manner, allowing real time communication among persons all over the world. However, as Web 2.0 Communities are a quite recent phenomenon with its own characteristics and particularities, there is still a necessity of developing new tools that allow to reach decisions with a high enough consensus level among their users. In this contribution we present a new consensus reaching model designed to incorporate the benefits that a Web 2.0 Community offers (rich and diverse knowledge due to a large number of users, real-time communication.. .) and that tries to minimize the main problems that this kind of organization presents (low and intermittent participation rates, difficulty of establishing trust relations and so on).
IEEE Transactions on Systems, Man, and Cybernetics: Systems, 2014
In the literature, we find that the consensus models proposed for group decision making problems ... more In the literature, we find that the consensus models proposed for group decision making problems are guided by consensus degrees and/or similarity measures and/or consistency measures [1]. When we work in heterogeneous group decision making frameworks, we have importance degrees associated with the experts by expressing their different knowledge levels on the problem. Usually, the importance degrees are applied in the weighted aggregation operators developed to solve the decision situations. In this paper, we study another application possibility, i.e., to use heterogeneity existing among experts to guide the consensus model. Thus, the main goal of this paper is to present a new consensus model for heterogeneous group decision making problems guided also by the heterogeneity criterion. It is also based on consensus degrees and similarity measures, but it presents a new feedback mechanism that adjusts the amount of advice required by each expert depending on his/her own relevance or importance level.
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Papers by Sergio Alonso