In a fuzzy metric space (X, M,*), where * is a continuous t-norm, a locally fuzzy contraction mapping is defined. It is proved that any locally fuzzy contraction mapping is a global fuzzy contractive. Also, if f satisfies the locally fuzzy contractivity condition then it satisfies the global fuzzy contractivity condition.

In the present work, a common fixed point theorem for self-maps on cone metric spaces is proved. Also two examples, which shows that our main theorem is generalized version of main theorems of [A. Branciari, Int. J. Math. Math. Sci., 29 (2002), no. 9, 531–536] and [L.G. Huang and X. Zhang, J. Math. Anal. Appl. 332 (2007), no. 2, 1468–1476], are given.

The target of this paper is to present partial fuzzy metric-preserving functions and characterize the functions $f:[0,1]\to[0,1]$ with this aspect. We give a characterization for partial fuzzy  metric-preserving functions considering the different t-norms. Also, we show that the topology induced by partial fuzzy metric does not preserve under these functions with  an example. Then we  give a characterization of those partial fuzzy metric-preserving functions which preserve completeness and contractivity under some conditions. Finally, we discussed the relation between fuzzy  metric preserving and partial fuzzy preserving functions.

In this paper, we extend very recent fixed point theorems in the setting of ordered non-Archimedean fuzzy metric spaces. We present some fixed point theorems for self-mappings satisfying generalized $(\phi,\psi)$-contraction conditions in partially ordered complete non-Archimedean fuzzy metric spaces. On the other hand, we consider a more general class of auxiliary functions in the contractivity condition and we extend recently fixed point theorems for complete ordered non-Archimedean fuzzy metric spaces.  Also, we present a few examples to illustrate the validity of the results obtained in the paper.

In this article, we extend some recently fixed point theorems in the setting of G−fuzzy metric spaces. We introduce some new concepts of contractions called γ-contractions and γ-weak contractions. We prove some fixed point theorems for mappings providing γ-contractions and γ-weak contractions. On the other hand, we consider a more general class of auxiliary functions in the contractivity condition.

Fuzzy analytical hierarchy process (Fuzzy-AHP) technique as a knowledge-driven approach relies on the geologist’ s input to weight the importance of each evidence layer is applied for prospectivity modeling of Au mineralization within the Takhte-soleyman district. Firstly, in current study, all of the criteria and sub-criteria which are gained from exploratory data (geochemistry, remote sensing, geology and tectonic) are weighted by using AHP and thereafter are transformed into [0-1] range based on the fuzzy logic. All fuzzified layers according to the calculated weights were synthesized and prospectivity modeling of Au mineralization based on the Fuzzy-AHP technique was generated. In this study, it was used another fuzzy method based on the fuzzy operators (OR and GAMMA) that called “ Fuzzy-GAMMA” to generate the map of promising areas of Au mineralization in the study area. Finally, in order to evaluate the ability of the applied methods in delineating reliable promising areas, locations of Au occurrences in the study area were used. Consequently, the results demonstrate the more acceptable outcomes for Fuzzy-AHP model by comparison with Fuzzy-GAMMA model.

Background and aims: Occurrence of accidents in the petroleum industry cause irreparable damage to human life. Understanding the causes of accidents takes place with analysis. One of the most important steps in accident analysis is a conscious selection of accident analysis method due to the existence of high variety of methods and various effective criteria. This study was carried out with the aim of selecting the optimal method for analysis of accidents in petroleum industry.Methods: A multi–criteria decision model was developed which was comprised of the analytic network process to obtain the criteria weights (which was used for selection of the accident analysis method) and fuzzy TOPSIS for ranking of the accident analysis methods.Results: Based on the results, 8 criteria and 19 sub criteria were used for selection of the accident analysis method. The factors of multiple levels cause identification capability, training need and levels of analysis with final weights of 0.375, 0.168 and 0.088 (respectively) had the most important weights in method selection. Based on fuzzy TOPSIS ranking of accident analysis method, tripod beta was selected as the optimal method and other methods such as BOW tie and MTO were in subsequent priorities.Conclusion: The results showed that there were several criteria (with different weight) for selecting the optimal method of accident analysis. Based on important of criteria incorporated in the present study, the optimal method for petroleum accident analysis is Tripod beta. Incorporation of Tripod beta in combination with the other methods may be resulted in numerous benefits in accident analysis.

Background: One of the main dilemmas of the human community has been municipal waste landfills. Various methods have been developed to manage municipal wastes in which landfills are the final destination apart from the used technologies. Given the sensitivity of this issue, identifing areas approriate for landfilling requires the application of comprehensive techniques. The objective of the present research is to select the most appropriate place for municipal wastes landfilling using geographical information systems, fuzzy analytic hierarchy process and fuzzy TOPSIS.Methods: Initially the effective factors in choosing landfill location was inquired from various institution and were standardized and analysed using geographical information systems. Then every criterion was weighted according to expert opinion and FAHP (Fuzzy Analytic Hierarchy Process). Then, FTOPSIS (Fuzzy Technique for Order Preference by Similarity to Ideal Solution) method was used to prioritize the options. Each method was programmed in MATLAB.Results: Thirty six suitable options were calculated through running the above mentioned methods. Then, two options that were located in the south east of the current landfilling (in Kulik) and Pakdasht city were selected as the best location for landfilling.Conclusion: Results showed that the selected landfills are located at a better position compared to the current one. And this integrated approach, showed a better performance than others due to taking into account the inexact nature of the phenomena both at weighting and ranking stages.