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We have developed a comprehensive approach to satisfying these requirements consisting of : a survivable object abstraction in which survivable services and applications can be developed ; a collection of models describing capabilities , needs , and threats ; and the architecture of a Survivability Service that manages the survival of systems constructed in accordance with the survivable object abstraction . Abstract : Fibre Diffraction and X-ray scattering afford the possibility of observing nanostructural changes in dynamic systems where the lattice and ordering of systems can be challenged by a number of factors . Control of systems can be performed directly in open loops in such a way that a certain criterium attains its optimal value . Currently , techniques used in " virtual " testing of systems can take months or even years to complete . From a technical point of view a continuous spectrum of systems can be conceived , ranging from collections of Ethernet-based workstations to tightly integrated custom multiprocessors .