Class-object hierarchies

NEXPERT OBJEXT represented domain specihc knowledge explicitly as networks of rules and class-object hierarchies. The rule-based and object-based representations are tightly integrated in a common design environment and are supported by visual editors and graphical browsers. 

Multiple inheritance To propagate information through class-object hierarchies and exception and uncertainty handlers. 

Notice that the add(), get(), remove(), and getIterator() methods do nothing but throw UnsupportedOperationException. This is because these operations are not available in the leaf objects in the composite hierarchy such as ChemicalSample. They only make sense in the composite objects such as ChemicalLibrary. Defining these methods in the component class makes the design compliant with The Liskov Substitution Principle (Martin, 2003). 

Divisive hierarchical simultaneous clustering procedures build a fuzzy hierarchy of objects and a fuzzy hierarchy of characteristics. Each node of the corresponding tree is labeled by a pair (C, D), where C is a fuzzy class of objects and D is a fuzzy class of characteristics. At the first level a binary fuzzy partition of data set X and the corresponding binary partition of characteristics set Y are computed. The classes that emerge are subdivided until no pair of real clusters can be obtained. 

A Class Hierarchy diagram showing the relationship between the various entities in the object-oriented knowledge base is shown in Figure 1. Each entity is implemented as a class in C+-h For example the object Quantity represents the attributes common to all scientific quantities. Each instance of a class represents a real-world object, for example Force is an instance of Quantity and Newton is an instance of the class Unit. 

Polymorphism Allows us to send the same message to different objects in different levels of class hierarchy. Each object responds in a way that is inherited or redefined with respect to the object s characteristics. 

Before discussing the implementation details, we need to state the general issues of multiple time-step numerical methods. The central objectives are (1) to devise a splitting of the systematic forces into a hierarchy of two or more force classes based on the time interval over which they vary significantly, and (2) to incorporate these force classes into a numerical method in a way that realizes enhanced computational efficiency and maintains stability and accuracy of the computed solution. 

Structural part. Here, all the available operators are characterised. In addition to the primitive HBBs (see physical part), we consider two other types of operators abstract building blocks (ABBs) and predefined EXUs/ASUs. These two types can be associated with abstraction hierarchy and architectural hierarchy respectively. Abstraction hierarchy is similar to class hierarchy in the object-oriented programming sense the operators are classified in a lattice, in which the ABBs are used at several levels of abstraction to represent... 

GenOM (Generic Object Model), represents and organizes the knowledge about Cl interdependencies through a three-leveled hierarchy of object classes (Lee Yavagal, 2004) ... 

The SystemUnitClassLibrary allows specifying the capabilities of solution equipment objects that can be matched with the requirements of objects defined with the role classes. A system unit class describes a physical or logical object including the concrete technical realization and internal architecmre. For example, a System Unit Class KRIOOO that matches with the role class robot may describe attributes of the KUKA KR 1000, which has a payload of 1,000 kg. Thereby system unit classes form a multi-level hierarchy of vendor-specific objects that can be instantiated within the InstanceHierachy. 

If many such abstractions are made from the superclasses, a tree hierarchy is formed in which the most general definition for object classes is given at the top of the tree, and each subclass at a lower level is more specific in its definition than the classes at higher levels. 

Figure 1 Hierarchy of classes and subclasses defined from a base class of (STANDARD OBJECTS). Classes that do not have immediate instances are called abstract classes (classes A, B, C, and D). Classes of this type normally identify properties that are useful in breaking large groups of objects into intermediate-level subsets. Each class can have several direct and indirect subclasses. Class A has 2 immediate subclasses and a total of 6 subclasses (of which 2 are abstract)...

We have not included any attributes in a molecule to store its name or list of names. Clearly, it would be desirable to store both a common, short name as well as a systematic name for a molecule it would also be desirable to allow for additional names, and provide methods to manipulate these attributes. In our OOP representation of biochemical systems, we will provide a generic mechanism which relies on a superclass called named object . Then, all we need to do is designate the named object as a superclass of molecules all the attributes and methods are then automatically inherited. This is an example of software reuse facilitated by OOP. Once we abstract a very generic behavior in one system, we can use that same behavior in many other systems, through the class hierarchy and multiple inheritance mechanisms of OOP. 

Figure 8-2 shows the relationships between the different entities of the physical data model that represents the plant physical structure. In this figure, plant equipment class specifications are represented in equipmentspec , while the equipment records are represented in equipment . Similarly for spare parts, itemspec is used to specify the class specifications while item is used to describe the spare parts instances i.e. objects. The specifications of the class hierarchy are represented in classstructure , classspec , and assetattribute . 

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