Browsing by Author "Cabrerizo, F. J."
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Item Open Access Challenges and Open Questions in Soft Consensus Models(2013-06) Cabrerizo, F. J.; Chiclana, Francisco; Ureña, M. R.; Herrera-Viedma, EnriqueIn group decision making problems, given the importance of obtaining an accepted solution by the whole group, the consensus has attained a great attention and it is virtually a major goal of these problems. Consensus, as traditionally meant to be a full and unanimous agreement, is often not reachable in practice. A more realistic approach is to use softer consensus measures, which assess the consensus degree in a more flexible way, and therefore reflect the large spectrum of possible partial agreements, guiding the consensus process until widespread agreement is achieved among experts. In particular, the interpretation of the consensus based on the concept of fuzzy majority has been used in the most of the consensus models proposed in the literature, as it is more human-consistent and suitable for reflecting human perceptions of the meaning of consensus. However, there are still some open questions to be addressed. In this paper, we are going to highlight some issues in order to focus researcher’s attention on new problems that arise when using consensus models based on soft consensus measures in real-world applications.Item Metadata only A decision aid system to provide consistent linguistic preference relations.(2006) Alonso, S.; Herrera-Viedma, Enrique; Chiclana, Francisco; Herrera, F.; Cabrerizo, F. J.Item Metadata only Fuzzy decision making and consensus: challenges(IOS Press, 2015-10) Cabrerizo, F. J.; Chiclana, Francisco; Al-Hmouz, Rami; Morfeq, Ali; Saeed Balamash, Abdullah; Herrera-Viedma, EnriqueGroup decision making is part of every organizational life. It is a type of participatory process in which multiple decision makers acting collectively, analyze problems, consider and evaluate several alternatives, and select from among the alternatives a solution. In such a situation, an important issue is the level of agreement or consensus achieved among the group of decision makers before obtaining the solution. In the beginning, consensus was meant as a full and unanimous agreement. Regrettably, this stringent concept of consensus in many cases is a utopia. As a result, and from a pragmatic point of view, it makes more sense to speak about a degree of consensus and, here, the theory of fuzzy sets has delivered new tools for the analysis of such imprecise phenomena like consensus. Given the significance of reaching an accepted solution by all the decision makers, consensus is a major aim of group decision making problems and, in such a way, it has obtained a great attention in the literature. However, there still exist several dares which have to be tackled by the researcherItem Open Access GDM-VieweR: A new tool in R to visualize the evolution of fuzzy consensus processes(2015) Urena, Raquel; Cabrerizo, F. J.; Chiclana, Francisco; Herrera-Viedma, EnriqueWith the incorporation of web 2.0 frameworks the complexity of decision making situations has exponentially increased, involving in many cases many experts, and a huge number of different alternatives. In the literature we can find a great deal of methodologies to assist multi-person decision making. However these classical approaches are not prepared to deal with such a huge complexity and there is a lack of tools that support the decision processes providing some graphical information. Therefore the main objective of this contribution is to present an open source tool developed in R to provide a quick insight of the evolution of the decision making by means of meaningful graphical representations. Thanks to the modular architecture of this solution this tool can be easily adapted to work with various Group decision making methodologies.Item Open Access GDMR A new framework in R to suppot Fuzzy Group Decision Making processes(2016) Urena, Raquel; Cabrerizo, F. J.; Chiclana, Francisco; Herrera-Viedma, EnriqueThis is a summary of our article published in Information Science [12] to be part of the MultiConference CAEPIA'15 KeyWorks.Item Open Access Group decision-making based on heterogeneous preference relations with self-confidence(Springer, 2016-11-29) Chiclana, Francisco; Herrera-Viedma, Enrique; Cabrerizo, F. J.; Dong, Yucheng; Liu, WenquPreference relations are very useful to express decision makers’ preferences over alternatives in the process of group decision-making. However, the multiple self-confidence levels are not considered in existing preference relations. In this study, we define the preference relation with self-confidence by taking multiple self-confidence levels into consideration, and we call it the preference relation with self-confidence. Furthermore, we present a two-stage linear programming model for estimating the collective preference vector for the group decision-making based on heterogeneous preference relations with self-confidence. Finally, numerical examples are used to illustrate the two-stage linear programming model, and a comparative analysis is carried out to show how self-confidence levels influence on the group decision-making results.Item Metadata only Group decision-making with incomplete fuzzy linguistic preference relations.(2009) Alonso, S.; Cabrerizo, F. J.; Chiclana, Francisco; Herrera, F.; Herrera-Viedma, EnriqueItem Metadata only Improving consistency in fuzzy preference relations with an allocation of information granularity(IOS Press, 2014-09) Cabrerizo, F. J.; Pedrycz, Witold; Chiclana, Francisco; Herrera-Viedma, EnriqueAn important issue to bear in mind in Group Decision Making situations is that of consistency. However, the expression of consistent preferences is often a very difficult task for the decision makers, specially in decision problems with a high number of alternatives and when decision makers use fuzzy preference relations to provide their opinions. It leads to situations where a decision maker may not be able to express all his/her preferences properly and without contradiction. To overcome this problem, we propose the concept of the information granularity being regarded as an important and useful asset supporting the goal to reach consistent fuzzy preference relations. To do so, we develop a concept of granular fuzzy preference relation where each pairwise comparison is formed as a certain information granule instead of a single numeric value. As being more abstract, the granular format of the preference model offers the required flexibility to increase the level of consistency.Item Metadata only An interactive decision support system based on consistency criteria.(Old City Publishing, 2008) Alonso, S.; Cabrerizo, F. J.; Chiclana, Francisco; Herrera, F.; Herrera-Viedma, EnriqueItem Metadata only An interactive support system to aid experts to express consistent preferences.(2006) Alonso, S.; Herrera-Viedma, Enrique; Chiclana, Francisco; Herrera, F.; Cabrerizo, F. J.Item Metadata only A Mobile Decision Support System for Dynamic Group Decision-Making Problems(IEEE, 2010-11) Pérez, I. J.; Cabrerizo, F. J.; Herrera-Viedma, EnriqueThe aim of this paper is to present a decision support system model with two important characteristic: 1) mobile technologies are applied in the decision process and 2) the set of alternatives is not fixed over time to address dynamic decision situations in which the set of solution alternatives could change throughout the decision-making process. We implement a prototype of such mobile decision support system in which experts use mobile phones to provide their preferences anywhere and anytime. To get a general system, experts’ preferences are assumed to be represented by different preference representations: 1) fuzzy preference relations; 2) orderings; 3) utility functions; and 4) multiplicative preference relations. Because this prototype incorporates both selection and consensus processes, it allows us to model group decision-making situations. The prototype incorporates a tool for managing the changes on the set of feasible alternatives that could happen throughout the decision process. This way, the prototype provides a new approach to deal with dynamic group decision-making situations to help make decisions anywhere and anytime.Item Embargo A New Selection Process Based on Granular Computing for Group Decision Making Problems(Springer International Publishing Switzerland, 2015-05) Cabrerizo, F. J.; Urena, Raquel; Morente-Molinera, Juan Antonio; Pedrycz, Witold; Chiclana, Francisco; Herrera-Viedma, EnriqueIn Group Decision Making, there are situations in which the decision makers may not be able to provide his/her opinions properly and they could contain contradictions. To avoid it, in this contribution, we present a new selection process to deal with inconsistent information. As part of it, we use a method based on granular computing to increase the consistency of the opinions given by the decision makers. To do so, each opinion is articulated as a certain information granule instead of a single numeric value, offering the necessary flexibility to increase the consistency. Finally, the importance of the decision makers’ opinions in the aggregation step is modeled by means of their consistency.Item Open Access A new type of preference relations: Fuzzy preference relations with self-confidence(IEEE, 2016) Chiclana, Francisco; Herrera-Viedma, Enrique; Cabrerizo, F. J.; Liu, Wenqu; Dong, Y.Preference relations are very useful to express decision makers’ preferences over alternatives in the process of decision-making. However, multiple self-confidence levels are not considered in existing preference relations. In this study, we propose a new type of preference relations: fuzzy preference relations with self-confidence. A linear programming model is proposed for estimating priority vectors of this new type of preference relations. Finally, two numerical examples are provided to demonstrate the linear programming model, and a comparative analysis is used to show the influence of self-confidence levels on the decision-making results.Item Embargo An opinion control rule with minimum adjustments to support the consensus reaching in bounded confidence model(Elsevier, 2016) Dong, Yucheng; Chiclana, Francisco; Herrera-Viedma, Enrique; Cabrerizo, F. J.; Ding, Zhaogang; Liang, HaimingOpinion dynamics provides a modeling tool for the public opinion management. The existing studies mainly focused on building the evolution model of opinions. However, the control of public opinions has been a key problem in practical opinion dynamics. The objective of this paper is to propose an opinion control rule to support the consensus reaching. Based on the bounded confidence model, the consensus model with the minimum adjustment is proposed. Next, based on the proposed consensus model, we propose the opinion control rule to support the consensus reaching. Furthermore, a numerical example is given to illustrate the feasibility of the proposed opinion control rule. Through simulation experiments, we investigate the effects of adjustment thresholds and bounded confidences on the opinion control rule.Item Metadata only A procedure to estimate missing information in group decision-making with fuzzy linguistic information(2007) Alonso, S.; Cabrerizo, F. J.; Herrera, F.; Herrera-Viedma, Enrique; Chiclana, FranciscoItem Metadata only A selection process to deal with incomplete fuzzy preference relations in a 2-tuple fuzzy linguistic approach(2008) Alonso, S.; Cabrerizo, F. J.; Herrera-Viedma, Enrique; Herrera, F.; Chiclana, FranciscoItem Embargo Soft consensus models in group decision making(Springer, 2016-04-06) Perez, Ignacio Javier; Cabrerizo, F. J.; Alonso, S.; Chiclana, Francisco; Herrera-Viedma, EnriqueIn group decision making problems, when a consensual solution is required, a natural question is how to measure the closeness among experts’ opinions in order to obtain the consensus level. To do so, different approaches have been proposed. Following this research line, several authors have introduced hard consensus measures varying between 0 (no consensus or partial consensus) and 1 (full consensus or complete agreement). However, consensus as a full and unanimous agreement is far from being achieved in real situations. So, in practice, a more realistic approach is to use some softer consensus measures, which assess the consensus degree in a more flexible way reflecting better all possible partial agreements obtained through the process. The aim of this chapter is to identify and describe the different existing approaches to compute soft consensus measures in fuzzy group decision making problems. Additionally, we analyze the current models Additionally, we analyze the current model and new challenges on this field.Item Metadata only Visualizing consensus in group decision making situations.(2007) Alonso, S.; Herrera-Viedma, Enrique; Cabrerizo, F. J.; Chiclana, Francisco; Herrera, F.Item Metadata only A web consensus support system to deal with GDM problems under incomplete fuzzy preference relations(2007) Alonso, S.; Cabrerizo, F. J.; Herrera-Viedma, Enrique; Herrera, F.; Chiclana, FranciscoItem Open Access A Web Information System to Improve the Digital Library Service Quality(2015) Cabrerizo, F. J.; Martinez, Maria Angeles; Lopez-Gijon, Javier; Chiclana, Francisco; Herrera-Viedma, EnriqueTo asses the quality of the services provided by a digital library, traditional measures, such as the size of its collection, have usually been utilized. However, service quality also has to be evaluated by considering users’ expectations. In addition, as a digital library plays an important role in the educational progress of a society, it is very important not only to measure the quality of its services but also to improve them. In this contribution, we present a web information system which supports the staff of a digital library to carry out decisions with the aim of improving the services offered by it. To do so, this system provides some advice taking into account both objective criteria, related to quantitative data, and subjective criteria, related to users’ judgments.