Kang, M., H.G. Dietz, and B. Bhargava, "Data Dependence Analysis
   for an Untrusted Transaction Manager in a Multilevel Database
   System"  Proc. of ISMM First International Conference on Information
   and Knowledge Management, Baltimore, 1992, pp. 441-448.
   <a href="1992kang-ikm.ps">
    PostScript</a>

<blockquote>
There are two components in the scheduler for multilevel-secure
databases which use the replicated architecture; global and local
schedulers.  Since the global scheduler, which enforces data
consistency among replicas, has to make scheduling decisions based on
transactions (i.e., without any knowledge of actual data or physical
layout of data), an accurate analysis technique which can detect
conflicts among queries is needed.  The data dependence analysis
introduced here provides a method for precisely determining whether the
portions of relations affected by various database operations overlap
without the knowledge of actual data.
</blockquote>