PowerType Absorbance

PowerTypes

The names of the powertype classes indicate that they are meta classes which aggregate general information about the base class. Therefore we find suffixes for the name of the power type classes likeModel, Species, Type, Kind etc.

Definition (PoPTC — Pair of Powertype Classes): PoPTC(C) = (C, PT(C)), where PT(C) is the power type class of C. Examples:

• C = ^Car and PT(C) = ^Car_Model ⇒PoPTC(^Car) = (^Car, ^Car_Model)
• PT(C) = ^PandaBear_Species ⇒ PoPTC(^PandaBear) = (^PandaBear, ^PandaBear_Species)
• C = ^MobilePhone and PT(C) = ^MobilePhoneModel ⇒PoPTC(^MobilePhone) = (^MobilePhone, ^MobilePhoneModel)

PowerType Absorbance

One of our main contributions to Multi-Level Modeling (MLM) is to show that all PoPTC(c) = (c, PT(c)) which are modeled with the Materialization Pattern (MP) can be merged into one class, thus reducing the complexity of the model considerably. Since the powertype PT(c) disappears while merging this transformation is coined PowerType Absorbance (PTA). If one would merge the classes MobilePhone and MobilePhoneModel as in [CaAl2011], Fig. 14 into one class MobilePhone, the Data Property (DP) launchDate would inevitably and undesirably instantiate into MobilePhone and imei would instantiate into IPhone5. The rules and templates for merging PoPTCs into one class c are:

• Particulars Data Properties(PDPs) of the c = MobilePhone are kept as a PDP, e.g., .imei, thus getting (MobilePhone’, .imei , ^String)
• PDPs of the PT(c) = MobilePhoneModel are type-shifted from an PDP to a CDP, e.g., .launchDate → .^^launchDate thus getting (MobilePhone’, .^^launchDate,^Date).
• Transparent Data Properties(TDPs) are type-shifted from, e.g., .ScreenSize to .^ScreenSize, resulting in(MobilePhone’, .^ScreenSize, ^String).

The merging of PoPTCs can be applied practically in every domain ontology. World-wide, there exist around 30k car models. As a consequence, by merging within a car ontology, about 30k classes can be saved by PTA. For species, through PTA more than 8.7 million classes can be saved in the species ontology.