Articles by Silvia Cavazzoni

Multivariate discriminant analyses were applied to the chemical composition data of four groups of fictile archaeological findings from the lagoon of Venice. Three groups are constituted of ceramic fragments of different manufacture, local and imported Byzantine originating from different epochs, from the Middle Ages to the Renaissance. The fourth group is formed of special Middle Age bricks (“altinelle”). Our aim was to first find the chemical characteristic of each group and, on this basis, to classify other unidentified findings. After having verified the structure of the four groups by means of PCA analysis, three discriminant canonical variates were determined: the relative weights of the original variables represent their discriminant power. The groups were also analysed in pairs and their relative discriminating variables were found. Discriminant function on the basis of the three new variates were calculated for each of the four groups and used for their verification. Finally a quadratic PCA analysis was applied to the first two variates of each group allowing, by means of recognition of their geometric form, to also identify non-linear relationships.

A particular type of multivariate analysis called “fuzzy c-means clustering” was applied to ancient bricks of 44 archaeological sites in the Lagoon of Venice, the remains of historical settlements of the last two thousand years. Each brick is characterized by its three geometrical dimensions, probably related to the local units of measure of the various epochs. The analysis was made with binary data (presence/absence) for the 20 principal types of bricks. The aim was to establish temporal relations among the various sites, some of which have definite temporal reference, allowing both to extend the references to the unknown sites and to evaluate, measuring the depth of the archaeological sites, the trend of the geological subsidence in the Venetian area. The results, compared also with those of a Correspondence Analysis, are, within some limitations, in agreement with the available dating from archivistic sources.