4 Information requirements

This clause specifies the information requirements for the Measure representation application module. The information requirements are specified as the Application Reference Model (ARM) of this application module.

NOTE 1  A graphical representation of the information requirements is given in Annex C.

NOTE 2  The mapping specification is specified in 5.1. It shows how the information requirements are met by using common resources and constructs defined or imported in the MIM schema of this application module.

This clause defines the information requirements to which implementations shall conform using the EXPRESS language as defined in ISO 10303-11. The following begins the Measure_representation_arm schema and identifies the necessary external references.

4.1 Required AM ARMs

The following EXPRESS interface statements specify the elements imported from the ARMs of other application modules.

EXPRESS specification:

*)
USE FROM Foundation_representation_arm;    --  ISO/TS 10303-1006



USE FROM Value_with_unit_arm;    --  ISO/TS 10303-1054
(*



NOTE 1   The schemas referenced above are specified in the following part of ISO 10303:

Foundation_representation_arm	ISO/TS 10303-1006
Value_with_unit_arm	ISO/TS 10303-1054

NOTE 2   See Annex C, Figures C.1and C.2 for a graphical representation of this schema.

4.2 ARM entity definitions

This subclause specifies the ARM entities for this module. Each ARM application entity is an atomic element that embodies a unique application concept and contains attributes specifying the data elements of the entity. The ARM entities and definitions are specified below.

4.2.1 Measure_item   

EXPRESS specification:

*)
ENTITY Measure_item
  ABSTRACT SUPERTYPE
  SUBTYPE OF (Representation_item);
WHERE
  WR1: SIZEOF(USEDIN(SELF, 'FOUNDATION_REPRESENTATION_ARM.REPRESENTATION.ITEMS'))>0;
END_ENTITY;
(*

Formal propositions:

WR1: an instance of this entity shall be an item of at least one Representation.

4.2.2 Numerical_item_with_global_unit   

EXPRESS specification:

*)
ENTITY Numerical_item_with_global_unit
  SUBTYPE OF (Measure_item);
  value_component : measure_value;
WHERE
  WR1: SIZEOF(QUERY(pvr <* QUERY ( r <* USEDIN(SELF, 'FOUNDATION_REPRESENTATION_ARM.REPRESENTATION.ITEMS')| 'MEASURE_REPRESENTATION_ARM.PROPERTY_VALUE_REPRESENTATION' IN TYPEOF(r)) | EXISTS(pvr.context_of_items.units) )) > 0;
END_ENTITY;
(*

Attribute definitions:

value_component: the value of the quantity. The type of this value shall be consistent with exactly one of the units globally assigned within the Numerical_representation_context.

EXAMPLE    If the item is a mass, there shall be exactly one Mass_unit in the units of the Numerical_representation_context.

Formal propositions:

WR1: an instance of this entity shall be an item of at least a Property_value_representation for which global units are specified.

4.2.3 Numerical_item_with_unit   

A Numerical_item_with_unit is a type of Measure_item that is also a Value_with_unit. The quantity value is therefore provided with its own unit.

NOTE    A unit that is specified by Numerical_item_with_unit supersedes a unit associated with the Numerical_representation_context.

EXPRESS specification:

*)
ENTITY Numerical_item_with_unit
  SUBTYPE OF (Measure_item, Value_with_unit);
END_ENTITY;
(*

4.2.4 Property_value_representation   

NOTE    The present version of this application module does not enable to represent whether the values have been imposed or were derived or measured. It is expected that a future version will add this capability.

EXPRESS specification:

*)
ENTITY Property_value_representation
  SUBTYPE OF (Representation);
  SELF\Representation.context_of_items : Numerical_representation_context;
END_ENTITY;
(*

Attribute definitions:

context_of_items: the Numerical_representation_context in which the value is represented.

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