2007, Vol. XIV, Núm. 1http://hdl.handle.net/2099/98632022-08-08T03:58:48Z2022-08-08T03:58:48ZAlgorithms for classification based on k-NNLaguía, ManuelCastro, Juan L.http://hdl.handle.net/2099/109292020-07-22T22:02:41Z2011-10-14T15:53:24ZAlgorithms for classification based on k-NN
Laguía, Manuel; Castro, Juan L.
In this paper we focus on methods that solve classification tasks based on distances, and we introduce some variants of the basic k-NN method adding up to 3 characteristics. The experiments reveal a relationship between the accuracy of 1-NN (distances) and the accuracy of the methods based on those distances. We propose a heuristics according to this observation and test its correctness. We study the usefulness of the proposed methods epsilon-ball, epsilon-ball^{k-NN} and epsilon-ball^{1-NN}, and make an exhaustive comparison using six different distance functions and 68 data sets, including UCI--Repository and artificial data sets. The proposed methods are useful and significantly outperform k-NN frequently. We have also found some evidence about the weakness of k-NN when the optimal value of $k$ varies in different regions along the space.
2011-10-14T15:53:24ZLaguía, ManuelCastro, Juan L.In this paper we focus on methods that solve classification tasks based on distances, and we introduce some variants of the basic k-NN method adding up to 3 characteristics. The experiments reveal a relationship between the accuracy of 1-NN (distances) and the accuracy of the methods based on those distances. We propose a heuristics according to this observation and test its correctness. We study the usefulness of the proposed methods epsilon-ball, epsilon-ball^{k-NN} and epsilon-ball^{1-NN}, and make an exhaustive comparison using six different distance functions and 68 data sets, including UCI--Repository and artificial data sets. The proposed methods are useful and significantly outperform k-NN frequently. We have also found some evidence about the weakness of k-NN when the optimal value of $k$ varies in different regions along the space.Weakening of fuzzy relational queries: an absolute proximity relation-based approachBosc, P.HadjAli, A.Pivert, O.http://hdl.handle.net/2099/109272020-07-22T22:02:40Z2011-10-14T15:46:18ZWeakening of fuzzy relational queries: an absolute proximity relation-based approach
Bosc, P.; HadjAli, A.; Pivert, O.
In this paper we address the problem of query failure in the context of flexible querying. We propose a fuzzy set–based approach for relaxing queries involving gradual predicates. This approach relies on the notion of proximity relation which is defined in an absolute way. We show how such proximity relation allows for transforming a given predicate into an enlarged one. The resulting predicate is semantically not far from the original one and it is obtained by a simple fuzzy arithmetic operation. The main features of the weakening mechanism are investigated and a comparative study with some methods proposed for the purpose of fuzzy query weakening is presented as well. Last, an example is provided to illustrate our proposal in the case of conjunctive queries.
2011-10-14T15:46:18ZBosc, P.HadjAli, A.Pivert, O.In this paper we address the problem of query failure in the context of flexible querying. We propose a fuzzy set–based approach for relaxing queries involving gradual predicates. This approach relies on the notion of proximity relation which is defined in an absolute way. We show how such proximity relation allows for transforming a given predicate into an enlarged one. The resulting predicate is semantically not far from the original one and it is obtained by a simple fuzzy arithmetic operation. The main features of the weakening mechanism are investigated and a comparative study with some methods proposed for the purpose of fuzzy query weakening is presented as well. Last, an example is provided to illustrate our proposal in the case of conjunctive queries.Homogeneity properties of hypercubesOvchinnikov, Sergeihttp://hdl.handle.net/2099/109262020-07-22T22:02:41Z2011-10-14T15:43:06ZHomogeneity properties of hypercubes
Ovchinnikov, Sergei
The paper reviews properties of hypercubes of arbitrary dimension from the metric geometry point of view. It is shown, in particular, that a hypercube is a homogeneous metric space with respect to a class of partial cubes. This generalizes the L1-rigidity property of finite partial cubes.
2011-10-14T15:43:06ZOvchinnikov, SergeiThe paper reviews properties of hypercubes of arbitrary dimension from the metric geometry point of view. It is shown, in particular, that a hypercube is a homogeneous metric space with respect to a class of partial cubes. This generalizes the L1-rigidity property of finite partial cubes.Characterizing Ordered Semigroups by Means of Intuitionistic Fuzzy Bi-idealsHong, YongfaXu, RuipingFang, Xianwenhttp://hdl.handle.net/2099/109232020-07-22T22:02:41Z2011-10-14T15:39:13ZCharacterizing Ordered Semigroups by Means of Intuitionistic Fuzzy Bi-ideals
Hong, Yongfa; Xu, Ruiping; Fang, Xianwen
In this paper, we endow set S with the structure of an ordered semigroup and define “intuitionistic fuzzy” analogous for several notions that have been proved to be useful in the theory of ordered semigroups and give some equivalent conditions of these definitions. Then we characterize the completely regular and the strongly regular ordered semigroups by means of intuitionistic fuzzy bi-ideals.
2011-10-14T15:39:13ZHong, YongfaXu, RuipingFang, XianwenIn this paper, we endow set S with the structure of an ordered semigroup and define “intuitionistic fuzzy” analogous for several notions that have been proved to be useful in the theory of ordered semigroups and give some equivalent conditions of these definitions. Then we characterize the completely regular and the strongly regular ordered semigroups by means of intuitionistic fuzzy bi-ideals.Convergences in perfect BL-algebrasCiungu, L.C.http://hdl.handle.net/2099/98672020-07-22T22:02:41Z2011-02-09T09:53:27ZConvergences in perfect BL-algebras
Ciungu, L.C.
The aim of the paper is to investigate some concepts of convergence in the class of
perfect BL-algebras. Similarity convergence was developed by G. Georgescu and A. Popescu in
the case of the residuated lattices, while the convergence with a fixed regulator was studied
by Cernák for lattice-ordered groups and MV-algebras and by the author for residuated lattices. In this paper we study the similarity convergence and the convergence with a fixed regulator for the perfect BL-algebras. The main result is the construction of Cauchy completion of a perfect BL-algebra.
2011-02-09T09:53:27ZCiungu, L.C.The aim of the paper is to investigate some concepts of convergence in the class of
perfect BL-algebras. Similarity convergence was developed by G. Georgescu and A. Popescu in
the case of the residuated lattices, while the convergence with a fixed regulator was studied
by Cernák for lattice-ordered groups and MV-algebras and by the author for residuated lattices. In this paper we study the similarity convergence and the convergence with a fixed regulator for the perfect BL-algebras. The main result is the construction of Cauchy completion of a perfect BL-algebra.