Consensus in a fuzzy environment: a bibliometric study

In today’s organizations, group decision making has become a part of everyday organizational life. It involves multiple individuals interacting to reach a decision. An important question here is the level of agreement or consensus achieved among the individuals before making the decision. Traditionally, consensus has been meant to be a full and unanimous agreement. However, it is often not reachable in practice. A more reasonable approach is the use of softer consensus measures, which assess the consensus in a more flexible way, reflecting the large spectrum of possible partial agreements and guiding the discussion process until widespread agreement is achieved. As soft consensus measures are more human-consistent in the sense that they better reflect a real human perception of the essence of consensus, consensus models based on these kind of measures have been widely proposed. The aim of this contribution is to present a bibliometric study performed on the consensus approaches that have been proposed in a fuzzy environment. It gives an overview about the research products gathered in this research field. To do so, several points have been studied, among others: countries, journals, top contributing authors, most cited keywords, papers and authors. This allows us to show a quick shot of the state of the art in this research area

The Inverse Scattering Method, Lie-Backlund Transformations and Solitons for Low-energy Effective Field Equations of 5D String Theory

In the framework of the 5D low-energy effective field theory of the heterotic string with no vector fields excited, we combine two non-linear methods in order to construct a solitonic field configuration. We first apply the inverse scattering method on a trivial vacuum solution and obtain an stationary axisymmetric two-soliton configuration consisting of a massless gravitational field coupled to a non-trivial chargeless dilaton and to an axion field endowed with charge. The implementation of this method was done following a scheme previously proposed by Yurova. We also show that within this scheme, is not possible to get massive gravitational solitons at all. We then apply a non-linear Lie-Backlund matrix transformation of Ehlers type on this massless solution and get a massive rotating axisymmetric gravitational soliton coupled to axion and dilaton fields endowed with charges. We study as well some physical properties of the constructed massless and massive solitons and discuss on the effect of the generalized solution generating technique on the seed solution and its further generalizations.Comment: 17 pages in latex, changed title, improved text, added reference

Approximate gravitational field of a rotating deformed mass

A new approximate solution of vacuum and stationary Einstein field equations is obtained. This solution is constructed by means of a power series expansion of the Ernst potential in terms of two independent and dimensionless parameters representing the quadrupole and the angular momentum respectively. The main feature of the solution is a suitable description of small deviations from spherical symmetry through perturbations of the static configuration and the massive multipole structure by using those parameters. This quality of the solution might eventually provide relevant differences with respect to the description provided by the Kerr solution.Comment: 16 pages. Latex. To appear in General Relativity and Gravitatio

Looking Over the Research Literature on Software Engineering from 2016 to 2018

This paper carries out a bibliometric analysis to detect (i) what is the most influential research on software engineering at the moment, (ii) where is being published that relevant research, (iii) what are the most commonly researched topics, (iv) and where is being undertaken that research (i.e., in which countries and institutions). For that, 6,365 software engineering articles, published from 2016 to 2018 on a variety of conferences and journals, are examined.This work has been funded by the Spanish Ministry of Science, Innovation, and Universities under Project DPI2016-77677-P, the Community of Madrid under Grant RoboCity2030-DIH-CM P2018/NMT-4331, and grant TIN2016-75850-R from the FEDER funds

Reaching Consensus in Digital Libraries: A Linguistic Approach

This work has been developed with the financing of FEDER funds in FUZZYLING-II Project TIN2010-17876, the Andalusian Excellence Projects TIC-05299 and TIC-5991, and Proyecto de Investigación del Plan de Promoción de la Investigación UNED 2011 (2011/PUNED/0003)2nd International Conference on Information Technology and Quantitative Management, ITQM 2014Libraries are recently changing their classical role of providing stored information into new virtual communities, which involve large number of users sharing real time information. Despite of those good features, there is still a necessity of developing tools to help users to reach decisions with a high level of consensus in those new virtual environments. In this contribution we present a new consensus reaching tool with linguistic preferences designed to minimize the main problems that this kind of organization presents (low and intermittent participation rates, difficulty of establishing trust relations and so on) while incorporating the benefits that a new digital library offers (rich and diverse knowledge due to a large number of users, real-time communication and so on). The tool incorporates some delegation and feedback mechanisms to improve the speed of the process and its convergence towards a consensual solution.FEDER funds in FUZZYLING-II Project TIN2010-17876Andalusian Excellence Projects TIC-05299 and TIC-5991Proyecto de Investigación del Plan de Promoción de la Investigación UNED 2011 (2011/PUNED/0003

Using Multi-granular Fuzzy Linguistic Modelling Methods to Represent Social Networks Related Information in an Organized Way

Social networks are the preferred mean for experts to share their knowledge and provide information. Therefore, it is one of the best sources that can be used for obtaining data that can be used for a high amount of purposes. For instance, determining social needs, identifying problems, getting opinions about certain topics, ... Nevertheless, this kind of information is difficult for a computational system to interpret due to the fact that the text is presented in free form and that the information that represents is imprecise. In this paper, a novel method for extracting information from social networks and represent it in a fuzzy ontology is presented. Sentiment analysis procedures are used in order to extract information from free text. Moreover, multi-granular fuzzy linguistic modelling methods are used for converting the information into the most suitable representation mean.This work has been supported by the ’Juan de la Cierva Incorporación’ grant from the Spanish Ministry of Economy and Competitiveness and by the Grant from the FEDER funds provided by the Spanish Ministry of Economy and Competitiveness (No. TIN2016-75850-R)

3D heterotic string theory: new approach and extremal solutions

We develop a new formalism for the bosonic sector of low-energy heterotic string theory toroidally compactified to three dimensions. This formalism is based on the use of some single non-quadratic real matrix potential which transforms linearly under the action of subgroup of the three-dimensional charging symmetries. We formulate a new charging symmetry invariant approach for the symmetry generation and straightforward construction of asymptotically flat solutions. Finally, using the developed approach and the established formal analogy between the heterotic and Einstein-Maxwell theories, we construct a general class of the heterotic string theory extremal solutions of the Israel-Wilson-Perjes type. This class is asymptotically flat and charging symmetry complete; it includes the extremal solutions constructed before and possesses the non-trivial bosonic string theory limit.Comment: 20 pages in Late

Comparing Electronic Monitoring and human observer collected fishery data in the tropical purse seine operating in the Western and Central Pacific Ocean

Electronic Monitory (EM) systems have been proven a valid tool for collecting fishery dependent data. They are being widely used in many fisheries as a complement or alternative to human observers to increase the monitoring coverage of fisheries. However, considering its wide application, following agreed minimum standard, it is important to compare the congruence between the information collected by EM and observers. We compared EM and two sets of different observer data collected on 6 trips of tuna purse seiners in the Eastern and Western and Central Pacific Ocean to analyze the similarity of fishing set type identification, estimation of tuna and bycatch catches between both monitoring systems. Overall EM was a valid tool to estimate the type of fishing set. Retained total catch of tunas by set was estimated by EM as reliable as that by both observer programs and logbook. When comparing the information by set, EM estimation of the main species, such as skipjack and bigeye and the combination of bigeye/yellowfin, was proven to be less accurate but statistically similar to the estimates made by both observers’ programs. EM tended to underestimate the retained catch of skipjack in comparison to both observers estimates and slightly overestimate bigeye and yellowfin, the overestimation being less pronounced for bigeye than for yellowfin. For bycatch species, EM is able to identify main bycatch species as observers do. However, the capability of EM to estimate the same number of bycatch items in comparison to IATTC and WCPFC observers varies greatly by species group. For sharks, which are the main bycatch issue in the FAD purse seine fishery, the overall congruence between EM and observers was high. EM and IATTC observer identified a similar overall number of individual sharks, however, WCPFC observers estimated lower number of shark individuals than the other two monitoring systems when considering all trips together.Versión del edito

Unwrapping Closed Timelike Curves

Closed timelike curves (CTCs) appear in many solutions of the Einstein equation, even with reasonable matter sources. These solutions appear to violate causality and so are considered problematic. Since CTCs reflect the global properties of a spacetime, one can attempt to change its topology, without changing its geometry, in such a way that the former CTCs are no longer closed in the new spacetime. This procedure is informally known as unwrapping. However, changes in global identifications tend to lead to local effects, and unwrapping is no exception, as it introduces a special kind of singularity, called quasi-regular. This "unwrapping" singularity is similar to the string singularities. We give two examples of unwrapping of essentially 2+1 dimensional spacetimes with CTCs, the Gott spacetime and the Godel universe. We show that the unwrapped Gott spacetime, while singular, is at least devoid of CTCs. In contrast, the unwrapped Godel spacetime still contains CTCs through every point. A "multiple unwrapping" procedure is devised to remove the remaining circular CTCs. We conclude that, based on the two spacetimes we investigated, CTCs appearing in the solutions of the Einstein equation are not simply a mathematical artifact of coordinate identifications, but are indeed a necessary consequence of General Relativity, provided only that we demand these solutions do not possess naked quasi-regular singularities.Comment: 29 pages, 9 figure