Search results for "Fuzzy number"
showing 10 items of 86 documents
Fuzzy Classifier Based on Fuzzy Decision Tree
2007
A popular method for making a fuzzy decision tree for classification is Fuzzy ID3 algorithm. We introduce a new approach that uses cumulative information estimations of initial data. Based on these estimations we propose a new greedy version of fuzzy ID3 algorithm to be used to generate understandable fuzzy classification rules. The goal is to find a sequence of rules that causes near minimal classification costs.
An Approach to the Concept of Soft Fuzzy Proximity
2014
The purpose of this paper is to introduce the concept of soft fuzzy proximity. Firstly, we give the definitions of soft fuzzy proximity and Katsaras soft fuzzy proximity, and also we investigate the relations between the soft fuzzy proximity and slightly modified version of Katsaras soft fuzzy proximity. Secondly, we induce a soft fuzzy topology from a given soft fuzzy proximity by using soft fuzzy closure operator. Then, we obtain the initial soft fuzzy proximity from a given family of soft fuzzy proximities. So, we describe products in the category of soft fuzzy proximities. Finally, we show that a family of all soft fuzzy proximities on a given set constitutes a complete lattice.
Different averages of a fuzzy set with an application to vessel segmentation
2005
Image segmentation is a major problem in image processing, particularly in medical image analysis. A great number of segmentation procedures produce intermediate gray-scale images that can be understood as fuzzy sets. Additionally, some segmentation procedures tend to leave free tuning parameters (very influential in the final binary image) for the user. These different binary images can be easily aggregated (into a fuzzy set) by making use of fuzzy set theory. In any case, a single binary image is required so our interest is to associate a crisp set to a given fuzzy set in an intelligent and unsupervised manner. The main idea of this paper is to define the averages of a given fuzzy set by …
Fuzzy fixed points of generalized F2-geraghty type fuzzy mappings and complementary results
2016
The aim of this paper is to introduce generalized F2-Geraghty type fuzzy mappings on a metric space for establishing the existence of fuzzy fixed points of such mappings. As an application of our result, we obtain the existence of common fuzzy fixed point for a generalized F2-Geraghty type fuzzy hybrid pair. These results unify, generalize and complement various known comparable results in the literature. An example and an application to theoretical computer science are presented to support the theory proved herein. Also, to suggest further research on fuzzy mappings, a Feng–Liu type theorem is proved.
A theory of spatial general equilibrium in a fuzzy economy
1984
Let an economic space be characterized by the existence of a given distribution of locations, i.e. consumers' residential locations and producers' plants. It is equipped with a system of prices. The economy is fuzzy because the economic behaviors of agents are imprecise. In this context, spatial partial equilibria theories are applications of a fuzzy economic calculation model. The aim of the present paper is to study the conditions which must be fulfilled in order that the compatibility of consumers' equilibria and producers' equilibria be verified. Mathematical tools are Butnariu's theorems which extend the Brouwer's and Kakutani's theorems to the cases of fuzzy functions and fuzzy point-…
A fuzzy framework to evaluate service quality in the healthcare industry: An empirical case of public hospital service evaluation in Sicily
2016
A novel fuzzy framework is considered to analyze healthcare service quality.The fundamental quality structure of healthcare service delivered in Sicily is described.The public healthcare in Sicily (Italy) is strategically analyzed.Strategic stakeholders' oriented implications for healthcare improvements are given. A novel fuzzy evaluation framework is applied in this study to evaluate service quality in the public healthcare sector. In particular, the proposed framework is based on the ServQual disconfirmation paradigm and incorporates the Analytic Hierarchy Process (AHP) method to elicit reliable estimations of service quality expectations. Moreover, degrees of uncertainty, subjectivity an…
A multi-criteria approach for the group assessment of an academic course: A case study
2015
The present paper aims at proposing a structured methodology to evaluate the results of an academic training course addressed to postgraduate students. The evaluation process intends to identify the efficacy of an education course bymeans of acomparison between the general objectives and the results expected by the students. Since the evaluated aspects by the students, detected by means of questionnaires, are both quantitative and qualitative, the proposed methodology is based on the analytic hierarchy process (AHP). In order to facilitate the evaluation process, answers have been modelled by means of linguistic variables. In particular, different evaluation scales have been used and each on…
Portfolio optimization using a credibility mean-absolute semi-deviation model
2015
We present a cardinality constrained credibility mean-absolute semi-deviation model.We prove relationships for possibility and credibility moments for LR-fuzzy variables.The return on a given portfolio is modeled by means of LR-type fuzzy variables.We solve the portfolio selection problem using an evolutionary procedure with a DSS.We select best portfolio from Pareto-front with a ranking strategy based on Fuzzy VaR. We introduce a cardinality constrained multi-objective optimization problem for generating efficient portfolios within a fuzzy mean-absolute deviation framework. We assume that the return on a given portfolio is modeled by means of LR-type fuzzy variables, whose credibility dist…
The facility layout problem approached using a fuzzy model and a genetic search
2005
The problem of facility layout design is discussed, taking into account the uncertainty of production scenarios and the finite production capacity of the departments. The uncertain production demand is modelled by a fuzzy number, and constrained arithmetic operators are used in order to calculate the fuzzy material handling costs. By using a ranking criterion, the layout that represents the minimum fuzzy cost is selected. A flexible bay structure is adopted as a physical model of the system while an effective genetic algorithm is implemented to search for a near optimal solution in a fuzzy contest. Constraints on the aspect ratio of the departments are taken into account using a penalty fun…
A multi-objective genetic algorithm for cardinality constrained fuzzy portfolio selection
2012
This paper presents a new procedure that extends genetic algorithms from their traditional domain of optimization to fuzzy ranking strategy for selecting efficient portfolios of restricted cardinality. The uncertainty of the returns on a given portfolio is modeled using fuzzy quantities and a downside risk function is used to describe the investor's aversion to risk. The fitness functions are based both on the value and the ambiguity of the trapezoidal fuzzy number which represents the uncertainty on the return. The soft-computing approach allows us to consider uncertainty and vagueness in databases and also to incorporate subjective characteristics into the portfolio selection problem. We …