Biologically active colloid-gold complexes were used to compare ligand-induced microaggregation, redistribution, and internalization of insulin receptors on Rat 1 fibroblasts expressing wild type (HIRc) or tyrosine kinase-defective (HIR A/K1018) human insulin receptors. Insulin-like growth factor I (IGF I) and alpha 2-macroglobulin receptors also were compared. On both cell types, all four unoc...

Microaggregation is a special clustering problem where the goal is to cluster a set of points into groups of at least k points in such a way that groups are as homogeneous as possible. Microaggregation arises in connection with anonymization of statistical databases for privacy protection (k-anonymity), where points are assimilated to database records. A usual group homogeneity criterion is wit...

In this paper we discuss how most edit constraints can be taken into account in an effective way through microaggregation. We discuss different edit constraints and some variations of microaggregation that permits to deal with such constraints. We will also present our software to formalize and deal with such constraints in an automatic way.

Privacy is becoming a pervasive issue, as nowadays information is gathered by all kind of information systems. In this paper we introduce a method for database protection in the case that the data under consideration is expressed in terms of time series. We propose the use of microaggregation for this purpose and extend standard microaggregation so that it works for this kind of data.

Nodulation, which begins with the formation of cellular microaggregates, is the predominant cellular defense reaction to bacterial infections in insects. We suggested that these reactions to bacterial infections are mediated by eicosanoids. The lipopolysaccharide (LPS) component of some bacterial cells stimulates defense reactions in mammals and insects. Here, we report on experiments designed ...

Microaggregation is a technique for protecting the privacy of respondents in individual data (microdata) releases. This papers starts with a survey of the general definitions and concepts related to microdata protection and then reviews the state of the art of microaggregation, to which our group has substantially contributed.

The field of statistical disclosure control aims to reduce the risk re-identifying an individual from disseminated data, a major concern among national agencies. Operations Research (OR) techniques have been widely used in past for protecting tabular but not microdata (i.e., files individuals and attributes). Few papers apply OR microaggregation problem, which is considered one best methods pro...

Microaggregation is one of the most important statistical disclosure control techniques for continuous data. The basic principle of microaggregation is to group the observations in a data set and to replace them by their corresponding group means. In this paper, we consider single-axis sorting, a frequently applied microaggregation technique where the formation of groups depends on the magnitud...

− Microaggregation is a technique that is used by statistical agencies to limit disclosure of sensitive microdata. Noting that no polynomial time algorithms are known to microaggregate optimally, Domingo-Ferrer and Mateo-Sanz have presented heuristic methods based on hierarchical clustering and genetic algorithms to identify sub-optimal solutions. We present an efficient polynomial time algorit...

Microaggregation is a masking procedure used for protecting confidential data prior to their public release. This technique, that relies on clustering and aggregation techniques, is solely used for numerical data. In this work we introduce a microaggregation procedure for categorical variables. We describe the new masking method and we analyse the results it obtains according to some indices fo...