Peter-Paul de Wolf

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The views expressed in this paper are those of the author and do not necessarily reflect the policies of Statistics Netherlands. This paper describes a heuristic approach to find suppression patterns in tables that exhibit a hierarchical structure in at least one of the explanatory variables. The hierarchical structure implies that there exist (many)(More)
PRAM is a probabilistic, perturbative method for disclosure protection of categorical variables in microdata files. If PRAM is to be applied, several issues should be carefully considered. The microdata file will usually contain a specific structure, e.g., a hierarchical structure when all members of a household are present in the data file. To what extent(More)
The software package τ-ARGUS offers a very efficient algorithm for secondary cell suppression known as either HiTaS or the Modular approach. The method is well suited for the protection of up to 3-dimensional hierarchical tables. In practice, statistical agencies release multiple tabulations based on the same dataset. Usually these tables are linked through(More)
1. Orienterend onderzoek werd gedaan naar de mogelijkheid om met de mossel (Mytilus edulis) als proefdier een meetnet voor zeewatervervuiling, speciaal met het oog O? metalen, op te bouwen. Hiertoe werden enkele malen mosselen verzameld van een aantal plaatsen langs de Nederlandse kust en d.m.v. emissiespektrografie of neutroaenaktivering geanalyseerd. 2.(More)
The views expressed in this paper are those of the authors and do not necessarily reflect the policies of Statistics Netherlands Explanation of symbols. = data not available * = provisional figure x = publication prohibited (confidential figure) – = nil or less than half of unit concerned – = (between two figures) inclusive 0 (0,0) = less than half of unit(More)