Search results for "Theoretical Computer Science"
showing 10 items of 1151 documents
Overlapping Community Structure in Co-authorship Networks: A Case Study
2014
Community structure is one of the key properties of real-world complex networks. It plays a crucial role in their behaviors and topology. While an important work has been done on the issue of community detection, very little attention has been devoted to the analysis of the community structure. In this paper, we present an extensive investigation of the overlapping community network deduced from a large-scale co-authorship network. The nodes of the overlapping community network represent the functional communities of the co-authorship network, and the links account for the fact that communities share some nodes in the co-authorship network. The comparative evaluation of the topological prop…
Impact of centrality on cooperative processes
2016
The solution of today's complex problems requires the grouping of task forces whose members are usually connected remotely over long physical distances and different time zones. Hence, understanding the effects of imposed communication patterns (i.e., who can communicate with whom) on group performance is important. Here, we use an agent-based model to explore the influence of the betweenness centrality of the nodes on the time the group requires to find the global maxima of NK-fitness landscapes. The agents cooperate by broadcasting messages, informing on their fitness to their neighbors, and use this information to copy the more successful agents in their neighborhood. We find that for ea…
Correlations among Game of Thieves and other centrality measures in complex networks
2021
Social Network Analysis (SNA) is used to study the exchange of resources among individuals, groups, or organizations. The role of individuals or connections in a network is described by a set of centrality metrics which represent one of the most important results of SNA. Degree, closeness, betweenness and clustering coefficient are the most used centrality measures. Their use is, however, severely hampered by their computation cost. This issue can be overcome by an algorithm called Game of Thieves (GoT). Thanks to this new algorithm, we can compute the importance of all elements in a network (i.e. vertices and edges), compared to the total number of vertices. This calculation is done not in…
A privacy-aware framework for decentralized online social networks
2015
Online social networks based on a single service provider suffer several drawbacks, first of all the privacy issues arising from the delegation of user data to a single entity. Distributed online social networks (DOSN) have been recently proposed as an alternative solution allowing users to keep control of their private data. However, the lack of a centralized entity introduces new problems, like the need of defining proper privacy policies for data access and of guaranteeing the availability of user's data when the user disconnects from the social network. This paper introduces a privacy-aware support for DOSN enabling users to define a set of privacy policies which describe who is entitle…
Artificial Vision and Soft Computing
1999
The term soft-computing has been introduced by Zadeh in 1994. Soft-computing provides an appropriate paradigm to program malleable and smooth concepts. For example, it can be used to introduce flexibility in artificial systems to improve their Intelligent Quotient. The aim of this paper is to describe the applicability of soft-computing to artificial vision problems. Good performance of this approach is assured by the fact that digital images are examples of fuzzy entities, where shapes are not always describable by exact equations and their approximation can be very complex.
Some reflections on Fuzzy Set Theory as an Experimental Science
2014
The aim of this paper is to open a critical discussion on the claim, recently presented in the community and especially heralded by Enric Trillas, that fuzzy logic should be seen as an “experimental science”. The first interesting aspect of such remark is whether and in which way such position has consequences on the real development of the research, or if it is simply a (different) way of looking at the same phenomenon. As a consequence, we investigate the possible connection to Zadeh’s distiction between Fuzzy logic in a restricted sense and in a general sense. We shall argue that Trillas’s claim not only strongly supports the necessity for such a distinction, but provides a path of inves…
Experimental modeling for a natural landing of fuzzy sets in new domains
2015
In this paper we plan to touch upon (and briefly discuss) some (out of the many) contributions done by Enric Trillas to Fuzzy Sets Theory. We have carefully chosen, from the abundant panorama we have been allowed to gaze at in the years, two different but intertwined topics of a more methodological character, which—as such—are, obviously, not only outside the topics massively developed by the scientific community in this field but also not in the mainstream of Enric’s investigations. We picked up them, however, since we believe that they are related to a crucial problem for the further developments of fuzzy research in the subsequent years. In this perspective, they represent a very signifi…
On Fuzziness, Its Homeland and Its Neighbour
2013
It has been frequently remembered (also in the invitation letter to contribute to the present volume) that in his 1962 paper [27] which is a sort of proto-manifesto of fuzzy sets [28], Zadeh among the possible names that could denote the new notion he was trying to introduce, basides fuzzy, mentioned the term cloudy. If he had chosen this last one as the name of the theory, today we had contributed to a volume On Cloudiness.
Soft Computing Methods for Personnel Selection Based on the Valuation of Competences
2014
Personnel selection based on candidates' competences is a difficult task due to the imprecise description of the applicants' competences and to the existence of several experts simultaneously evaluating those attributes. In this context, fuzzy sets theory provides suitable tools for the attainment of the maximum possible information from imprecise data. In this work, personnel selection methods are proposed that rely on the definition of an ideal candidate. Aggregated fuzzy valuations of each candidate are obtained taking into account the individual valuations provided by the experts. Then, candidates are ranked based on their similarity with the ideal candidate. Three different scenarios a…
Suffix array and Lyndon factorization of a text
2014
Abstract The main goal of this paper is to highlight the relationship between the suffix array of a text and its Lyndon factorization. It is proved in [15] that one can obtain the Lyndon factorization of a text from its suffix array. Conversely, here we show a new method for constructing the suffix array of a text that takes advantage of its Lyndon factorization. The surprising consequence of our results is that, in order to construct the suffix array, the local suffixes inside each Lyndon factor can be separately processed, allowing different implementative scenarios, such as online, external and internal memory, or parallel implementations. Based on our results, the algorithm that we prop…