Page 336 - Practical Design Ships and Floating Structures

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decomposed to several easier cases, and every case can be decomposed hierarchy upon hierarchy. In
each hierarchy, the case can be used independently. In the before mentioned, the result of compartment
layout design is expressed by complex object structure. Because these objects have the format that is
needed in case presentation and their properties can present result data of the compartment layout
design, the object structure that present result of compartment layout design can present the case of
compartment layout design directly. The object structure that is the result of the compartment layout
design is always the instantiation of certain kind of layout design object class or the origin object.
According to the inheritance principle in the object-oriented method, these cases can inherit the
dynamic knowledge in the object class which they belong to. So using the object-oriented method to
present knowledge of ship compartment layout design principle can present the data of compartment
layout design case and solving knowledge of design conveniently. Fig.1 is the decomposition
presentation of ship compartment layout design case.

Compartment

Command module

Barn layout case 1
layout case 1

Figure 1 : the decomposition presentation of ship compurhnent layout design case.
In the light of integration of hierarchical structure decomposition of the ship compartment layout
design case and the object-oriented presentation method of ship compartment layout design knowledge,
the compartment layout design case can be utilized not only as a whole, but also merely some parts of
it. Therefore, as long as the design requirement of compartment design is identical with the object class,
the new layout design objective will be composed from the subcase of different layout design objects
according to compartment layout design knowledge.
Index of cases is another important part of case presentation of compartment design case. Index is the
appearance property in compartment design case; index of cases is gist of selecting compartment
layout design case based on case machine. The most convenient means to index a layout case is using
a sequence of compartment layout design case feathers as the index of layout case. To each object class
of layout design, an indexing type will be created in terms of its feather. In the process of layout design,
when design object class is instantiated to a case of layout design object, the index object class also
instantiated to the index of this object case, index object case include the record of index feather and
the names of compartment layout cases needed indexed.

3 THE CASE INDEXING MODEL OF COMPARTMENT LAYOUT BASED ON NEURAL
NETWORK
Before discussing the arithmetic, two notion are defined. One is degree of similitude which is the
measurement of to what degree two compartment layout design case are similar. The second is
dimension which describes compartment layout design space$ relates to the feather notion of
compartment layout design case. If the layout case has N pieces of property, the presentation space of