Catálogo de publicaciones - libros

This paper presents a new interest point descriptors representation method based on empirical mode decomposition (EMD) and independent components analysis (ICA). The proposed algorithm first finds the characteristic scale and the location of the interest points using Harris-Laplacian interest point detector. We then apply the Hilbert transform to each component and get the amplitude and the instantaneous frequency as the feature vectors. Then independent components analysis is used to model the image subspace and reduces the dimension of the feature vectors. The aim of this algorithm is to find a meaningful image subspace and more compact descriptors. Combination the proposed descriptors with an effective interest point detector, the proposed algorithm has a more accurate matching rate besides the robustness towards image deformations.

In a distributed environment, authorizations are usually physically stored in several computers connected by a network. Each computer may have its own local policies which could conflict with the others. Therefore how to make a global decision from the local authorization policies is a crucial and practical problem for a distributed system. In this paper, three general integration models based on the degrees of node autonomy are proposed, and different strategies of integrating the local policies into the global policies in each model are systematically discussed. The discussion is based on the weighted authorization graph model that we proposed before.

Association rules are typically evaluated in terms of support and confidence measures, which ensure that discovered rules have enough positive evidence. However, in real-world applications, even considering only those rules with high confidence and support it is not true that all of them are interesting. It may happen that the presentation of all discovered rules can discourage users from interpreting them in order to find nuggets of knowledge. Association rules interpretation can benefit from discovering group of “similar” rules, where (dis)similarity is estimated on the basis of syntactic or semantic characteristics. In this paper, we resort to the multi-dimensional scaling to support a visual exploration of association rules by means of bi-dimensional scatter-plots. An application in the domain of biomedical literature is reported. Results show that the use of this visualization technique is beneficial.

In this paper, we present an evaluation of learning algorithms of a novel rule evaluation support method for post-processing of mined results with rule evaluation models based on objective indices. Post-processing of mined results is one of the key processes in a data mining process. However, it is difficult for human experts to completely evaluate several thousands of rules from a large dataset with noises. To reduce the costs in such rule evaluation task, we have developed the rule evaluation support method with rule evaluation models which learn from a dataset. This dataset comprises objective indices for mined classification rules and evaluations by a human expert for each rule. To evaluate performances of learning algorithms for constructing the rule evaluation models, we have done a case study on the meningitis data mining as an actual problem. Furthermore, we have also evaluated our method with five rule sets obtained from five UCI datasets.

This paper investigates problems related to quality assessment in the case of multi-label automatic classification of data, using -Nearest Neighbor classifier. Various methods of assigning classes, as well as measures of assessing the quality of classification results are proposed and investigated both theoretically and in practical tests. In our experiments, audio data representing short music excerpts of various emotional contents were parameterized and then used for training and testing. Class labels represented emotions assigned to a given audio excerpt. The experiments show how various measures influence quality assessment of automatic classification of multi-label data.

This paper addresses fuzzy weighted multi-cross-level association rule mining. We define a fuzzy data cube, which facilitates for handling quantitative values of dimensional attributes, and hence allows for mining fuzzy association rules at different levels. A method is introduced for single dimension fuzzy weighted association rules mining. To the best of our knowledge, none of the studies described in the literature considers weighting the internal nodes in such taxonomy. Only items appearing in transactions are weighted to find more specific and important knowledge. But, sometimes weighting internal nodes on a tree may be more meaningful and enough. We compared the proposed approach to an existing approach that does not utilize fuzziness. The reported experimental results demonstrate the effectiveness and applicability of the proposed fuzzy weighted multi-cross-level mining approach.

In this paper we present a stepwise method for the analysis of musical sequences. The starting point is either a MIDI file or the score of a piece of music. The result is a set of likely themes and motifs. The method relies on a pitch intervals representation of music and an event discovery system that extracts significant and repeated patterns from sequences. We report and discuss the results of a preliminary experimentation, and outline future enhancements.

Despite many recent developments, there are still a number of central issues in inductive databases that need more research. In this paper we address two of them. The first issue is about how the discovery of patterns can use existing patterns. We will give a concrete example showing an advantage of mining both the patterns and the data. The second issue we consider is the actual implementation of inductive databases. We will propose an architectural framework for inductive databases and show how existing databases can be incorporated.

Within 0/1 data, co-clustering provides a collection of bi-clusters, i.e., linked clusters for both objects and Boolean properties. Beside the classical need for grouping quality optimization, one can also use user-defined constraints to capture subjective interestingness aspects and thus to improve bi-cluster relevancy. We consider the case of 0/1 data where at least one dimension is ordered, e.g., objects denotes time points, and we introduce co-clustering constrained by interval constraints. Exploiting such constraints during the intrinsically heuristic clustering process is challenging. We propose one major step in this direction where bi-clusters are computed from collections of local patterns. We provide an experimental validation on two temporal gene expression data sets.

The purpose of our research is to identify the critical variables, to evaluate the performance of variable selection, to evaluate the performance of a two-level SOM and to implement this methodology into Asian online game market segmentation. Conclusively, our results suggest that weight-based variable selection is more useful for market segmentation than full-based and SEM-based variable selection. Additionally, a two-level SOM is more accurate in classification than K-means and SOM. The critical segmentation variables and the characteristics of target customers were different among countries. Therefore, online game companies should develop diverse marketing strategies based on characteristics of their target customers using research framework we propose.