Basic concepts of system elements in the logical and physical domain.

Concept	Documentation
System Of Interest	An abstract element representing a SOI. Base class for specific kinds of SOIs.
Logical Context SOI	Represents the Logical SOI in the System Context on Logical Level.
Physical SOI	Represents the Physical SOI on Physical Level.
General Physical Role	General concept of usage of system elements in the context of other system elements on physical level.
Hardware Element Role	Specifies the fact that a hardware structure comprises hardware elements.
Software Element	Pure Software Elements. Similarity with the V-Model "software unit".
Software Element Role	Specifies the fact that a software structure comprises software elements.
Physical Software Role	Specifies the fact that a physical structure comprises software elements.
Physical Element Role	Specifies the fact that a physical structure comprises physical elements.
Physical Hardware Role	Specifies the fact that a physical structure comprises hardware elements.
Physical Element	A composition of Hardware and Software Elements. Similarity with the V-Model segments and system. See [VXT].
Hardware Element	Pure Hardware Elements. Similarity with the V-Model "hardware unit".
Logical Element	Describes a conceptual Logical Element as specification for an implementation of a system, or system element.
Abstract Physical Element	Abstract element representing physical structure items keeping properties and relations applicable to all physical items.
Logical Element Role	Specifies the fact that a logical element comprises logical elements.
LETspecifyingAPE	Specifies the fact that one or more Logical Element specifies exactly one Physical Element. Rationale: If more than one Physical Element would offer to realize the functionality specified by a Logical Element the responsibility would be ambiguous. It is okay to assign several Logical Elements to one Physical Element. This means all specified functionality assigned to the Logical Elements is to be implemented by the Physical Element. Note, that typically the usage of logical elements in a context is mapped to the usage of physical elements in a context (allocation of usage). Thus this relationship between the definitions is derived.
LERspecifyingGPR	Specifies that a usage of a Logical Element specifies functions for the usage of a Physical Element.
System	An abstract element representing a System.