AN EVALUATION OF ONLINE DATABASES BY METHODS OF LATTICE THEORY

The evaluation of databases is of great importance for potential users . The usual technique to define a ranking index however is not helpful , because users may have different interests concerning databases. The refore evaluation techniques are needed, which do not mask different e lements of information performing a ranking. The appropriate technique is given by the theory of order relation which leads to partially ord ered sets. Partially ordered sets can be visualized by Hasse diagrams. In this contribution 15 databases are characterised by five quality c riteria and the Hasse diagram shows that there are four databases whic h are best suitable with respect to different aspects, namely GAS, ECD IN, BEILSTEIN and HSDB. These four databases are further investigated by the formal concept analysis. A comprehensive diagram shows the spec ialities of each of these four databases and logical rules are automat ically derived, which show that there are interdependencies between qu alities within the context of the four priority databases. For example a good quality with respect to the use of chemicals implies a good qu ality of the general extent of the database with respect to the chemic als.