Search results for " operations"
showing 10 items of 1066 documents
Best Proximity Point Results in Non-Archimedean Fuzzy Metric Spaces
2013
We consider the problem of finding a best proximity point which achieves the minimum distance between two nonempty sets in a non-Archimedean fuzzy metric space. First we prove the existence and uniqueness of the best proximity point by using di fferent contractive conditions, then we present some examples to support our best proximity point theorems.
A class of label-correcting methods for the K shortest paths problem
2001
In this paper we deal with the problem of finding the first K shortest paths from a single origin node to all other nodes of a directed graph. In particular, we define the necessary and sufficient conditions for a set of distance label vectors, on the basis of which we propose a class of methods which can be viewed as an extension of the generic label-correcting method for solving the classical single-origin all-destinations shortest path problem. The data structure used is characterized by a set of K lists of candidate nodes, and the proposed methods differ in the strategy used to select the node to be extracted at each iteration. The computational results show that: 1. some label-correct…
Upper and lower approximations of general aggregation operators based on fuzzy rough sets
2015
Our paper deals with constructions of upper and lower general aggregation operators which act on fuzzy sets. These constructions are based on fuzzy rough sets and provide two approximations (upper and lower) of the pointwise extension and the t-extension of an ordinary aggregation operator. Considering two lattices of corresponding general aggregation operators we describe two approximate systems with respect to a lattice of fuzzy equivalence relations.
An Exact Algorithm for the Quadratic Assignment Problem on a Tree
1989
The Tree QAP is a special case of the Quadratic Assignment Problem (QAP) where the nonzero flows form a tree. No condition is required for the distance matrix. This problem is NP-complete and is also a generalization of the Traveling Salesman Problem. In this paper, we present a branch-and-bound algorithm for the exact solution of the Tree QAP based on an integer programming formulation of the problem. The bounds are computed using a Lagrangian relaxation of this formulation. To solve the relaxed problem, we present a Dynamic Programming algorithm which is polynomially bounded. The obtained lower bound is very sharp and equals the optimum in many cases. This fact allows us to employ a redu…
Some dissenting views on the transitivity of individual preference
1990
(1) The transitivity property is not a necessary condition for the rationality of all individual preference relations. (2) A weakened definition of the transitivity is not necessarily relevant. (3) The non-transitivity of fuzzy preference relations is not inconsistent with a fuzzy total preorder structure on the set of alternatives.
New Encodings of Pseudo-Boolean Constraints into CNF
2009
International audience; This paper answers affirmatively the open question of the existence of a polynomial size CNF encoding of pseudo-Boolean (PB) constraints such that generalized arc consistency (GAC) is maintained through unit propagation (UP). All previous encodings of PB constraints either did not allow UP to maintain GAC, or were of exponential size in the worst case. This paper presents an encoding that realizes both of the desired properties. From a theoretical point of view, this narrows the gap between the expressive power of clauses and the one of pseudo-Boolean constraints.
A family of distances for preference–approvals
2022
Producción Científica
Unravelling the moderating effects of size and experience on product innovations and exports: a study in a medium knowledge-intensive industry
2012
This paper contributes to improve our knowledge on the important role of product innovation in export strategy by introducing the moderating effects of organizational variables. We argue that in a medium knowledge-intensive industry, these variables might strengthen the relationship between innovations and exports. Research on innovation and export strategy has addressed these issues increasingly during last decades; however, the divergence on the empirical approaches difficult the understanding of the linkages among variables, which are highly dependent on the industry technological characteristics. We carry out a time-lagged study using the literature-based innovation output (LBIO) method…
Exploring the relationships between maritime connectivity, international trade and domestic production
2020
The objective of this paper is to simultaneously analyse the complex relationships between bilateral maritime connectivity, bilateral trade and domestic production as measured by gross domestic pro...
Asymmetric behaviour of biotechnology business patterns in Spain
2009
Since the end of the 90s there has been an increase in the emergence of biotechnology industries in Spain, partially as a result of growing support from institutionally based infrastructures. Through the use of empirical fieldwork, this study aims to reveal how future prospects are not as optimistic as most Spanish agents perceive. Our conclusions are based on the asymmetric behaviour shown by Spanish biotechnology firms in their business models. This asymmetry is based on the overwhelming dominance of business models centred on low investment, limited R&D expenditure and minor or incremental innovation, whereas the long term–long return model, which prevails in the leading countries in thi…