Substructure subsystem

There is some difficulty with using an intuitive notion of complexity, as we have been. How can we decide more precisely what we mean by "complexity" of a system The initial intuition is that any system is more complex than any of its proper subsystems. The solar system example shows that this intuition fails when the focus with which the system is considered changes. An alternative intuition is that the complexity of a system might be measured by the number and diversity of its component atomic entities (in this sense, an entity is atomic in any consideration of a structure if we do not inquire into its substructure). This also fails in that it does not deal well with the fact that a static structure, or an instantaneous snapshot of a structure, is a less complex entity than a dynamic structure that contains the same atomic units. There may be an information theoretic measure of the complexity of a system in terms of the number of bits of information required to specify its observable properties at the required focus. 

Composite crystals are crystalline structures that consist of two or more periodic substructures, each one having its own 3-D periodicity to a first approximation. The symmetry of each of these subsystems is characterized by one of the 230 space groups. However, owing to their mutual interaction, the fine structure consists of a collection of incommensurately modulated subsystems. All known composite stractures to date have at least one lattice direction in common and consist of a maximum of three substructures. There are three main classes ... 

Nuclear power plant structures may be very complex and a single complete model of the entire structure would be too cumbersome or possibly iU conditioned. The analysis should therefore identify the substructures by defining main systems and subsystems. 

The systems analysis showed that it was important for Dialog to adopt a fully integrated subsystem that would effectively perform structure and substructure searches. Such a subsystem would permit the Dialog program to remain in control of all the communications functions to the user s terminal, but would use searching techniques that were different from those of Dialog and more appropriately suited to the handling of structure information. 

Interaction effects and in particular damping effects between the subsystems are neglected. The resulting conservatisms are especially important if the substructure is excited with a frequency near its resonance frequency, i.e., when the resulting vibrations are most important. 

The fixed-interface method discussed in the preceding section requires the knowledge of subsystem structural matrices, and for this reason, they are not suited if one or more of the subsystems are studied experimentally (Maia and de Silva 1997). Also, creating fixed interfaces for substructures in experimental work is generally not feasible. An alternative formulation to overcome these difficulties is as follows. Consider the substmcture Eq. 1 and determine the natural frequencies and mode shapes by solving the eigenvalue problem A A = AM A- This leads to the Na x Na matrices A = diag[ct) ] and such that = 7 and... 

This equation can now be analyzed to deduce the built-up system natural frequencies and mode shapes. It is emphasized that the mass and stiffness matrices for the built-up system here are constmcted in terms of the natural frequencies, and mode shapes of the subsystem in the uncoupled states and knowledge of substructure structural matrices are not needed in this formulation. This enables the introduction of experimentally studied substructures to be embedded into the modal synthesis of the built-up system. 

Cross Reference file. The connection table in the Registry Structure file is accessed for a given NSC Number by the IRN present in the NSC record of the Cross Reference file. The name and address and other control information for a given supplier in the Miscellaneous file is accessed by the supplier code in the NSC record for a given compound. The NSC Numbers of all the compounds scheduled for shipment on a specific Material Shipping List (MSL) is accessed for a specific carton of samples by the MSL number in the MSL record in the Miscellaneous file. As will be described later, the INQUIRY subsystem uses the search Indexes and Inverted lists to be lead to NSC Numbers and their associated data in response to full structure or substructure searches. (See Table 2 for the size and growth rate of the DR D CIS files.)... 

---