PHYSICAL-OBJECTs are classified into MATERIALs, PLACEs, and SEPARABLE-ENTITYs. MATERIALs are classified under several dimensions at the same time: into SOLIDs and FLUIDs; into ELEMENT-MATERIALs and CHEMICAL-COMPOUNDs; based on their origin, such as, into METALs, PLANT-DERIVED-SUBSTANCEs and ANIMAL-DERIVED-SUBSTANCEs; and into various categories based on their use such as CLEANSING-MATERIALs, PHARMACEUTICAL-MATERIALs, and POISONOUS-SUBSTANCEs. FLUIDs are in turn classified into SOLIDs and LIQUIDs. A good example of multiple classifications can be seen between these and the element/compound classifications: both ELEMENT-MATERIALs and CHEMICAL-COMPOUNDs are in turn classified into their solid, liquid, and gaseous subclasses. The MATERIAL ontology is shown in Figure 2.
Figure 2:
Parts of the Classification of Materials in the Ontology.
PLACEs classified into GEOGRAPHICAL-ENTITYs, BUILDINGs, BUILDING-PARTs, and SPACEs. SPACEs include various types of openings. GEOGRAPHICAL-ENTITYs are further classified into ENVIRONMENTAL-ENTITYs such as DESERT and GRASSLANDS, BODY-OF-WATER such as OCEAN and RIVER, GEOGRAPHICAL-MARKERs, GEOLOGICAL-ENTITYs such as MOUNTAINs, VOLCANOes, and the major continents, and GEOPOLITICAL-ENTITYs. GEOPOLITICAL-ENTITYs also fall under SOCIAL-OBJECTs and will be described in the corresponding section below. Important concepts in the ontology of PLACEs are shown in Figure 3.
Figure 3:
Parts of the Classification of Places in the Ontology.
SEPARABLE-ENTITYs are classified into ANIMATE and INANIMATE objects. ANIMATE objects are further divided into PLANTs, ANIMALs, and ANIMATE-PARTs. Further classification of these trees follows our intuition and knowledge of biology to a large extent and will not be described here. However, it is worth noting that HUMAN is under PRIMATE which is under MAMMAL which, in turn, is under VERTEBRATE, a child of ANIMAL. A major tree of SOCIAL-ROLEs sits directly under HUMAN. Once again, SOCIAL-ROLE is also under SOCIAL-OBJECT and will be visited in sufficient detail in the corresponding section below.
INANIMATE objects are classified into ARTIFACTs, INGESTIBLEs, and NATURAL-OBJECTs. The ARTIFACT tree is big, as expected, and will not be described here. INGESTIBLEs include all types of FOOD and DRINK. NATURAL-OBJECTs include NATURAL-RESOURCEs, CELESTIAL-OBJECTs, and GEOGRAPHICAL-ENTITYs which were included under PLACEs above.
The ontology of SEPARABLE-ENTITYs is shown in Figure 4 . This concludes our tour of PHYSICAL-OBJECTs.
Figure 4:
Parts of the Classification of Separable Entities in the Ontology.
Kavi Mahesh