On the cell suppression by merging technique in the lattice model of summary tables

The authors investigate the suitability of the cell suppression by merging (CSM) technique as an SDB (statistical database) protection mechanism, and give various heuristic algorithms for the minimum information loss. They first revise the definition for the information loss when query probabilities are taken into account. This definition reflects the actual utilization of cells in the lattice. The authors then propose a heuristic approach to be used with the CSM technique. This approach tries to minimize the information loss by properly choosing the merging pairs. Experimental results show that, in most cases, the information loss is lower than that of the case in which the query probabilities are not considered. This indicates that the actual information loss under query probabilities is low when the CSM technique is combined with the heuristic approach. It is concluded that the CSM technique is therefore an effective protection mechanism for summary tables. It is also shown that the CSM technique is also applicable in the generalized lattice model as an effective security enforcement mechanism. The authors propose several heuristic approaches to minimize the information loss when this technique is applied