The State Scientific Center of the Russian Federation--Institute of Physics and Power Engineering's (SSC RF-IPPE) practice of nuclear material control and accounting (MC&A) has undergone significant changes during the period of cooperation with U.S. national laboratories from 1995 to the present. These changes corresponded with general changes of the Russian system of state control and accounting of nuclear materials resulting from the new Concept of the System for State Regulating and Control of Nuclear Materials (1996) and further regulatory documents, which were developed and implemented to take into account international experience in the MC&A [1]. During the upgrades phase of Russian-U.S. cooperation, an MC&A laboratory was specially created within the SSC RF IPPE for the purpose of guiding the creation of the upgraded MC&A system, coordinating the activities of all units involved in the creation of this system, and implementing a unified technical policy during the transition period. After five years of operation of the MC&A laboratory and the implementation of new components for the upgraded MC&A system, it was decided that a greater degree of attention must be paid to the MC&A system's operation in addition to the coordination activities carried out by the MC&A laboratory. To meet this …

We present some theoretical and experimental results of animportant caching problem that arises frequently in data intensivescientific applications. In such applications, jobs need to processseveral files simultaneously, i.e., a job can only be serviced if all itsneeded files are present in the disk cache. The set of files requested bya job is called a file-bundle. This requirement introduces the need forcache replacement algorithms based on file-bundles rather then individualfiles. We show that traditional caching algorithms such Least RecentlyUsed (LRU), and GreedyDual-Size (GDS), are not optimal in this case sincethey are not sensitive to file-bundles and may hold in the cachenon-relevant combinations of files. In this paper we propose and analyzea new cache replacement algorithm specifically adapted to deal withfile-bundles. We tested the new algorithm using a disk cache simulationmodel under a wide range of parameters such as file requestdistributions, relative cache size, file size distribution,and queuesize. In all these tests, the results show significant improvement overtraditional caching algorithms such as GDS.