This is an upper ontology based on ISO-15926. A [class_of_biological_matter] is a [class_of_arranged_individual] whose members are particular types of cell or aggregations of cells. EXAMPLE. The classes known as 'blood', 'enzyme', and 'plasma' can be represented by instances of [class_of_biological_matter]. A [class_of_activity] is a [class_of_arranged_individual] whose members are instances of [activity]. EXAMPLE. Drilling, distilling, and approving can be represented by instances of [class_of_activity]. NOTE. Behaviour is a term used to describe a [class_of_activity] either where there are preconditions and the [class_of_activity] is a response to those preconditions, e.g. reaction to touching a hot surface, or where the way an activity occurs is described by some property or function, e.g. fluid flow being described by the viscosity of the fluid. A [class_of_lifecycle_stage] is a [class_of_relationship] whose members are members of [lifecycle_stage]. EXAMPLE. Planned, required, expected, and proposed can be represented by instances of [class_of_lifecycle_stage]. A [class_of_identification] is a [class_of_representation_of_thing] that indicates that the pattern is used to refer to the represented thing. EXAMPLE. The link between the pattern 'AC-1234' and a particular pump, indicating that members of 'AC-1234' are used to refer to the pump, can be represented by an instance of [class_of_identification]. A [class_of_class_of_relationship] is a [class_of_class] whose members are instances of [class_of_relationship]. EXAMPLE Reflexive is an example of [class_of_class_of_relationship]. A reflexive [class_of_relationship] is one that may have the same [thing] playing both roles, such as connection, where something may be connected to itself. A [multidimensional_property_space] is a [property_space] and a [multidimensional_object] whose members are properties each of which maps to more than one number. Each property will consist of elements of the same property dimensions. EXAMPLE. A pump performance curve of flowrate and differential head is a [multidimensional_property_space]. 1 A [class_of_specialization] is a [class_of_relationship] whose members are instances of [specialization]. It indicates that a member of the class_of_subclass is a subclass of a member of the class_of_superclass. EXAMPLE. The [class_of_specialization] that indicates that members of the class "family of ASME bolts", e.g. 3 inch, 2 inch bolts, are specializations of members of the [enumerated_property_set] "set of bolt lengths", e.g. 3 inch, 2 inch. 1 [class] A [class] is a [thing] that is an understanding of the nature of things and that divides things into those which are members of the class and those which are not according to one or more criteria. The identity of a [class] is ultimately defined by its members. No two classes have the same membership. However, a distinction must be made between a [class] having members, and those members being known, so within an information system the members recorded may change over time, even though the true membership does not change. NOTE 1 The membership of a [class] is unchanging as a result of the spatio-temporal paradigm upon which this schema is based. In another paradigm it might be stated that a car is red at one time, and green at another time, indicating that the class of red things and class of green things changed members. However, using a spatio-temporal paradigm, a temporal part, state 1, of the car is red, and another temporal part of the car, state 2, is green. In this way the members of the classes red and green are unchanging. The same principle applies to future temporal parts as to past temporal parts, it is just more likely that the membership of these is not known. A class may be a member of another class or itself. NOTE 2 The set theory that applies to classes in this model is non-wellfounded set theory [3]. This permits statements like "class is a member of class", unlike traditional set theories such as Zermelo-Fraenkel set theory found in standard texts [4]. There is a null [class] that has no members. NOTE 3 The known members of a [class] are identified by [classification]. EXAMPLE 1 Centrifugal pump is a [class]. EXAMPLE 2 Mechanical equipment type is a [class]. EXAMPLE 3 Temperature is a [class]. EXAMPLE 4 Commercial fusion reactor is a [class]. NOTE 4 Although there is only one [class] that has no members, there can be a [class] that has no members in the actual world, but which does have members in other possible worlds. EXAMPLE 5 Centigrade scale is a [class]. BIBLIOGRAPHY [3] ACZEL, Peter. Non-Well-Founded Sets, Center for the Study of Language and Information, Stanford, California, 1988, ISBN 0937073229. [4] IT K. (editor). Encyclopedic Dictionary of Mathematics, Mathematical Society of Japan, Edition 2, Cambridge, Massachusetts, MIT Press, 1993, ISBN 0262590204. 1 1 A [dimension_of_individual] is a [class_of_relationship] that indicates that each member of the set of lines that are the [individual_dimension] are a dimension of the [possible_individual]. EXAMPLE. The set of all lines that pass through the centre of a particular circle and end at the circumference of that circle, are a dimension (diameter) of that circle. The particular dimension is indicated by the [dimension_of_shape] that classifies the [dimension_of_individual]. A [representation_form] is a [class_of_class_of_information_representation] that distinguishes the form of representation. EXAMPLE. Hexadecimal, text, script, symbol, picture, diagram, semaphore, Morse code, music score, MIDI file format, and XML can each be represented by instances of [representation_form]. An [arithmetic_number] is a [class_of_class] whose member classes have the same sign and count or magnitude. An [arithmetic_number] is the number itself, not any representation of the number. NOTE. [integer_number] is not a subtype of [real_number]. The members of [integer_number] are part of a different continuum from the members of [real_number], but are isomorphic to a subset of it. EXAMPLE 1. The number 2 and the number 2.0 can be represented by instances of [arithmetic_number]. EXAMPLE 2. Fifteen, the number itself not the English word "fifteen", is an [arithmetic_number]. It could be represented by an [EXPRESS_integer] or an [EXPRESS_real] but could also be represented by "XV", or a binary, or a hexadecimal representation. A [class_of_isomorphic_functional_mapping] is a [class_of_functional_mapping] that is isomorphic. EXAMPLE. The natural logarithm function is a [class_of_isomorphic_functional_mapping]. A [stream] is a [physical_object] that is material or energy moving along a path, where the path is the basis of identity and may be constrained. The stream consists of the temporal parts of those things that are in the stream whilst they are in it. EXAMPLE. Flux is a 4D-constrained case of [stream] where the path crosses a surface. EXAMPLE. The naphtha flowing in a pipe between a crude distillation unit and a platformer is a [stream]. A [class_of_class] is a [class] whose members are instances of [class]. NOTE. When it is necessary to classify a [class_of_class], another [class_of_class] can be used. This is because a [class_of_class] is a [class]. A [class_of_particulate_material] is a [class_of_arranged_individual] whose members are arranged amounts of super-molecular sized objects of the same or different types. EXAMPLE. Pile of sand, sand and cement mix, bag of bolts, catalyst fill for a reactor are examples of [class_of_particulate_material]. 1 1 A [class_of_class_of_individual] is a [class_of_class] whose members are instances of [class_of_individual]. EXAMPLE. "Premium Product" is a [class_of_class_of_individual] that has [class_of_individual] "mogas" as a member. A [whole_life_individual] is a [possible_individual] that is a member of a [class_of_individual], and is not a temporal part of any other [possible_individual] that is also a member of the same [class_of_individual]. A [whole_life_individual] includes its past and future. NOTE. A possible future temporal part of the [whole_life_individual] is a [possible_individual] that is related to the [whole_life_individual] by a [temporal_whole_part] relation. EXAMPLE 1. A plastic cup (bounded by its creation and destruction [event]s) can be represented by an instance of [whole_life_individual]. The cup whilst it stands on this table is a temporal part of this [whole_life_individual]. EXAMPLE 2. The universe for all time is a [whole_life_individual]. A <class_of_relationship_with_related_end_2> is a [class_of_relationship] where a particular [thing] is related in the [class_of_relationship], rather than the members of a [class]. The related [thing] plays the [role_and_domain] indicated by the class_of_end_2 attribute. EXAMPLE. Possession of welding skills by John Doe is an example of <class_of_relationship_with_related_end_2>, where John Doe is the related thing. 1 1 A [class_of_connection_of_individual] is a [class_of_relationship] whose members are members of [connection_of_individual]. It indicates that a member of the class_of_side_1 [class_of_individual] can be connected to a member of the class_of_side_2 [class_of_individual]. NOTE 1. The class_of_side_1 and class_of_side_2 indicate the [class_of_individual] that is the side_1 and side_2 respectively in a [connection_of_individual] that is a member of this [class_of_connection_of_individual]. NOTE 2. Flexible, rigid, and welded cannot be represented as instances of [class_of_connection_of_individual], these are classes of the materials connected or used in the connection. EXAMPLE. Electrical connection between wires is a [class_of_connection_of_individual]. 1 A [single_property_dimension] is a [property_space] that is a single and complete continuum of properties each of which maps to a single number. EXAMPLE. Temperature, pressure, viscosity, and length are examples of [single_property_dimension]. A [class_of_point_in_time] is a [class_of_event] whose members are members of [point_in_time]. EXAMPLE. Midnight is a [class_of_point_in_time] A [multidimensional_scale] is a [scale] that is also a [multidimensional_object]. EXAMPLE A [Celsius, seconds] scale is a [multidimensional_scale] on which temperature variation over time can be plotted. A [period_in_time] is a [possible_individual] that is all space for part of time - a temporal part of the universe. EXAMPLE 1. July 2000 is an instance of [period_in_time]. EXAMPLE 2. The period described by UTC 2000-11-21T06:00 to UTC 2000-11-21T11:53 is an instance of [period_in_time] compliant with ISO8601. A [class_of_atom] is a [class_of_arranged_individual] whose members are atoms. EXAMPLE. All entries in the periodic table of elements can be represented by instances of [class_of_atom]. A [document_definition] is a [class_of_class_of_information_representation] that defines the content and/or structure of documents. EXAMPLE. XYZ Corp. Material Safety Data Sheet is a [document_definition]. A [class_of_scale] is a [class_of_class_of_relationship] whose members are instances of [scale]. EXAMPLE. SI Unit. A [language] is a [class_of_class_of_information_representation] whose members are all the information representations made in the language. EXAMPLE. English, French, C++ and Java can be represented by instances of [language]. 1 1 A [functional_physical_object] is a [physical_object] that has functional, rather than material, continuity as its basis for identity. Adjacent temporal parts of a [functional_physical_object] need not have common matter or energy, provided the matter or energy of each temporal part fulfils the same function. EXAMPLE. The heat exchanger system known as tag E-4507, which is part of a distillate transfer system, can be represented by an instance of [functional_physical_object]. Note that this is distinct from the "shell and tube heat exchanger manufacture number ES/1234" that was installed as E-4507 when the plant was first built and later removed when worn out, to be replaced by a new heat exchanger with different serial number. "Shell and tube heat exchanger manufacture number ES/1234" and its differently numbered replacement can be represented by instances of materialized_physical_object]. When ES/1234 is installed as E-4507 there is a temporal part of ES/1234 that is also a temporal part of E-4507. A [class_of_composite_material] is a [class_of_arranged_individual] whose members have a common arrangement of separable compounds. EXAMPLE 1. Laminates such as plywood, fibreglass, and carbon fibre can be represented by instances of [class_of_composite_material]. EXAMPLE 2. Wood, muscle, and skin can be represented by instances of [class_of_composite_material]. 1 1 1 1 A [class_of_relative_location] is a [class_of_relationship] whose members are instances of [relative_location]. EXAMPLE. Beside, above, and below are examples of [class_of_relative_location]. 1 1 A [class_of_usage_of_representation] is a [class_of_relationship] whose members indicate that a [possible_individual] (usually an organization) reads or otherwise uses members of the pattern as a representation of the represented thing. EXAMPLE. The link between the identification of pump #1234 and contractor ABC Ltd, that indicates that ABC Ltd uses this identification can be represented by a class of [class_of_usage_of_representation]. A [point_in_time] is an [event] that is the whole space extension with zero extent in time. NOTE. In using this part of ISO15926, a [point_in_time] should be represented by a [UTC_representation_of_time]. EXAMPLE. The time known as UTC 1999-05-13T16:31:23.56 is a [point_in_time]. An [event] is a [possible_individual] with zero extent in time. An [event] is the temporal boundary of one or more [possible_individual]s, although there may be no knowledge of these [possible_individual]s. EXAMPLE. The connection of power to a pump is an event that marks the beginning of a temporal part of that pump. A [class_of_organism] is a [class_of_arranged_individual] whose members are living organisms. EXAMPLE. Human being, sheep, earthworm, oak tree, and bacteria are instances of [class_of_organism]. 1 A [property_for_shape_dimension] is a [class_of_class_of_relationship] that indicates that the members of the [shape_dimension] are of the [property]. EXAMPLE. 10m diameter is a 10m length. 1 1 A class_of_relationship_with_related_end_1 is a [class_of_relationship] where a particular [thing] is related in the [class_of_relationship], rather than the members of a [class]. The related [thing] plays the [role_and_domain] indicated by the class_of_end_1 attribute. EXAMPLE. Products manufactured by Bloggs Co is a [class_of_relationship] that points to Bloggs Co as the related [thing]. An [arranged_individual] is a [possible_individual] that has parts that play distinct roles with respect to the whole. The qualities of an [arranged_individual] are distinct from the qualities of its parts. EXAMPLE 1. The vessel with serial number V-1234 is an [arranged_individual]. EXAMPLE 2. The company Bloggs Co. is an [arranged_individual]. EXAMPLE 3. A laptop computer that consists of the main unit with its removable CD-ROM and floppy disk drives and power supply cables is an [arranged_individual]. A [coordinate_system] is a [multidimensional_scale] for locating and relating a [possible_individual] in an n-dimensional space in which arbitrary geometric transformations are valid. EXAMPLE. The XYZ site coordinate system, is an example of a coordinate system. <possible_individual> A <possible_individual> is a <thing> that exists in space and time. This includes: - things where any of the space time dimensions are vanishingly small, - those that are either all space for any time, or all time and any space, - the entirety of all space time - things that actually exist, or have existed, - things that are fictional or conjectured and possibly exist in the past, present or future, - temporal parts (states) of other individuals, - things that have a specific position, but zero extent in one or more dimensions, such as points, lines, and surfaces. In this context existence is based upon being imaginable within some consistent logic, including actual, hypothetical, planned, expected, or required individuals. EXAMPLE The pump with serial number ABC123, Battersea Power Station, Sir Joseph Whitworth, Shakespeare, and the starship "Enterprise" can be represented by instances of <possible_individual>. A [class_of_temporal_whole_part] is a [class_of_composition_of_individual] whose members are members of [temporal_whole_part]. EXAMPLE. The class that indicates that Crude Distillation Units may have a maximum naphtha mode can be represented by an instance of [class_of_temporal_whole_part]. A [multidimensional_property] is a [property] that is also a [multidimensional_object]. EXAMPLE. A pump flow head characteristic is a multidimensional object. It consists of a continuum of Q, H property pairs, where Q is the flow rate and H is the flowing head difference. Each pair of properties Qa and Ha, where Qa is a particular flow rate and Ha a particular head, is a multidimensional property [Qa, Ha]. A [class_of_class_of_information_representation] is a [class_of_class_of_individual] that classifies information representation classes. EXAMPLE. Integer Octal is a [class_of_class_of_representation] whose members are all the information representation classes that correspond to Octal formatted integers. A [shape] is a [property] that depends on constant relations of position and proportionate distance among all the points composing its outline or its external surface. EXAMPLE 1. 20mm diameter circle and 10-20mm diameter circles are examples of [shape]. A [spatial_location] is a [physical_object] that has continuity of relative position. EXAMPLE. Geographic datum, license block, construction area, country, air corridor, maritime traffic zone, hazard control zone, 4D points, lines, planes, solids. 1 1 A [class_of_involvement_by_reference] is a [class_of_relationship] whose members are instances of [involvement_by_reference]. EXAMPLE. Discussion of historical activities is an example of [class_of_involvement_by_reference]. A [class_of_definition] is a [class_of_representation_of_thing] that indicates the pattern is a definition of the represented [class]. EXAMPLE. The link between the pattern 'something that moves liquid' and the [class] that goes by the name 'pump' in English can be represented by an instance of [class_of_definition]. A [class_of_feature] is a [class_of_arranged_individual] whose members are contiguous, non-separable parts of some [possible_individual] and have an incompletely defined boundary. EXAMPLE. The classes known as 'mountain', 'groove', 'rim', 'nozzle', 'nose', and 'raised face' can all be represented as instances of [class_of_feature]. A [class_of_direct_connection] is a [class_of_connection_of_individual] whose members are members of [direct_connection]. EXAMPLE. Three-pin electrical plug into three-pin socket is an example of [class_of_direct_connection]. A [class_of_sub_atomic_particle] is a [class_of_arranged_individual] whose members are constituent particles of atoms. EXAMPLE. Proton, electron, meson, neutron, positron, muon, quark, and neutrino can be represented by instances of [class_of_sub_atomic_particle]. A [class_of_compound] is a [class_of_arranged_individual] whose members consist of arrangements of molecules of the same or different types, bound together by intermolecular forces. This includes both mixtures and alloys. EXAMPLE. Water, sulphuric acid, sand, limestone, and steel can be represented by instances of [class_of_compound]. A [physical_object] is a [possible_individual] that is a distribution of matter, energy, or both. EXAMPLE 1. A piece of metal is a [physical_object]. EXAMPLE 2. A tree is a [physical_object] EXAMPLE 3. The thing identified by tag P101 is a [physical_object]. EXAMPLE 4. A light beam is a [physical_object]. EXAMPLE 5. A tank that is built and dismantled on site is both a [materialized_physical_object] and a [functional_physical_object]. A [class_of_individual_used_in_connection] is a [class_of_relationship] whose members are members of [individual_used_in_connection]. It indicates that a member of the [class_of_individual] is used in a [class_of_connection_of_individual]. EXAMPLE. The link between the [class_of_connection_of_individual] that indicates that B12 type beams are connected to pipe hangers, and the [class_of_individual] "20mm Diameter bolt", that indicates that four 20mm diameter bolts are used in the connection of a pipe hanger to a type B12 beam can be represented by an instance of [class_of_individual_involved_in_connection]. 1 1 An [activity] is a [possible_individual] that brings about change by causing the [event] that marks the [beginning], or the [event] that marks the [ending] of a [possible_individual]. An activity consists of the temporal parts of those members of [possible_individual] that participate in the activity. The participating temporal parts will be classified by the [participating_role_and_domain] that indicates the role of the temporal part in the [activity]. EXAMPLE: Pumping a fluid with a mechanical pump can be represented by an instance of [activity]. 1 1 A [class_of_possible_role_and_domain] is a <class of relationship> that indicates the [role_and_domain] that can be played by a member of the [class_of_individual], in some [activity]. EXAMPLE. Pumps can play the [role] of anchor (although they are not intended to do so). 1 1 A [class_of_number] is a [class_of_class] whose members are members of [arithmetic_number]. EXAMPLE. The class of prime numbers can be represented by an instance [class_of_number]. A [role_and_domain] is a [class] that specifies the domain and role for an end of a [class_of_relationship] or [class_of_multidimensional_object]. NOTE A [role_and_domain] is analogous to specifying an EXPRESS attribute or its inverse. EXAMPLE "Husband and man" and "wife and woman" are examples of [role_and_domain]. A [materialized_physical_object] is a [physical_object] that has matter and/or energy continuity as its basis for identity. Matter or energy continuity requires some matter or energy to be common to adjacent temporal parts of the [materialized_physical_object]. Replacement of some components from time to time does not create a new identity. EXAMPLE. The shell and tube heat exchanger with manufacturer's serial number ES/1234 can be represented by an instance of [materialized_physical_object]. A [class_of_property] is a [class_of_class_of_individual] whose members are instances of [property]. EXAMPLE. 'Temperature' is an example of [class_of_property]. A [class_of_feature_whole_part] is a [class_of_arrangement_of_individual] whose members are instances of [feature_whole_part]. EXAMPLE. Thermowells have stems, and tables have tops are examples of [class_of_feature_whole_part]. A [status] is a [class_of_individual] that is a characteristic or quality that is described by discrete, unordered values. EXAMPLE. The classes known as 'open', 'painted', 'approved', 'old', 'new', 'worn', 'hazardous', 'safe', 'dangerous', 'happy', 'sad', and 'rusty' can all be represented as instances of [status]. NOTE. Degrees of openness or paintedness are represented as instances of [property] and not instances of [status]. A [representation_of_Gregorian_date_and_UTC_time] is a [class_of_information_representation] whose members are representations of time using the UTC system of time identification as specified in ISO 8601:2000 together with the Gregorian system for representing dates. All times shall be represented using UTC representation of time. Dates shall follow the Gregorian calendar. NOTE. Coordinated Universal Time (UTC) is the basis for legal time worldwide and follows TAI (see below) exactly except for an integral number of seconds, presently 32. These leap seconds are inserted on the advice of the International Earth Rotation Service (IERS) (http://hpiers.obspm.fr) to ensure that, on average over the years, the Sun is overhead within 0.9 seconds of 12:00:00 UTC on the meridian of Greenwich. UTC is thus the modern successor of Greenwich Mean Time, GMT, which was used when the unit of time was the mean solar day. International Atomic Time (TAI) is calculated by the BIPM from the readings of more than 200 atomic clocks located in metrology institutes and observatories in more than 30 countries around the world. TAI is made available every month in the BIPM Circular T (ftp://62.161.69.5/pub/tai/publication). It is estimated that TAI does not lose or gain with respect to an imaginary perfect clock by more than about one tenth of a microsecond (0.0000001 second) per year. A [class_of_relationship] is a <class_of _abstract_object> whose members are members of [relationship]. An [enumerated_property_set] is a [class_of_property] and an [enumerated_set_of_class] whose members are an enumerated set of properties of the same [single_property_dimension] or [multidimensional_property_space]. EXAMPLE. {115 Volt, 240 Volt} is an example of an [enumerated_property_set]. 1 1 A [shape_dimension] is a [class_of_class_of_individual] that is a set of [individual_dimension] that define an aspect of a shape. EXAMPLE. Diameter of 5m, height of 3mm, and width of 10cm are members of [shape_dimension]. 1 1 A [class_of_person] is a [class_of_organism] whose members are people. EXAMPLE. Engineer, plant manager, student, male, female, senior citizen, adult, girl, and boy can be represented by instances of [class_of_person]. Engineer, plant manager, and student are also instances of [class_of_functional_object]. A [class_of_molecule] is a [class_of_arranged_individual] whose members are molecules. EXAMPLE. H2O, H2SO4, and DNA can be represented by instances of [class_of_molecule]. A [class_of_composition_of_individual] is a [class_of_relationship] whose members are members of [composition_of_individual]. EXAMPLE. That piles of sand may have grains of sand as parts is an example of [class_of_composition_of_individual]. 1 1 A [class_of_functional_object] is a [class_of_arranged_individual] that indicates the function or purpose of an object. EXAMPLE. Pump, valve, and car are examples of [class_of_functional_object]. Particular models of pump, valve, car, etc are instances of [class_of_inanimate_physical_object] that are specializations of these instances of [class_of_functional_object]. A [class_of_participation] is a [class_of_composition_of_individual] that indicates a member of an instance of [participating_role_and_domain] participates in a member of an instance of [class_of_activity]. EXAMPLE "Conductor of a musical performance" is an example of [class_of_participation]. 1 1 A [scale] is a [class_of_isomorphic_functional_mapping] whose members are members of [property_quantification]. It indicates the [number_space] a [property_space] maps to for the [scale] in question. EXAMPLE. The link that is known as the Celsius scale between the [class_of_number] [-273, inf] and the [class_of_property] temperature can be represented by an instance of [scale]. A [class_of_inanimate_physical_object] is a [class_of_arranged_individual] whose members are not living. EXAMPLE. The class known as 'oil' can be represented by an instance of [class_of_inanimate_physical_object]. A [class_of_period_in_time] is a [class_of_individual] whose members are instances of [period_in_time]. EXAMPLE. Monday and June are examples of [class_of_period_in_time]. A [class_of_assembly_of_individual] is a [class_of_arrangement_of_individual] whose members are instances of [assembly_of_individual]. EXAMPLE. That impellers are parts of centrifugal pumps is a [class_of_assembly_of_individual]. 1 1 A [class_of_responsibility_for_representation] is a [class_of_relationship] whose members indicate that a [possible_individual] (usually an organization) deems that members of the pattern can be used as representations of the represented thing. EXAMPLE. The link between the identification of pump #1234 and the XYZ Corporation, that indicates that the XYZ Corporation controls this identification, can be represented by an instance of [class_of_responsibility_for_representation]. An [individual_dimension] is a [class_of_individual] whose members characterize a particular [possible_individual]. EXAMPLE. The set of lines that are each a diameter of a particular circle. A [class_of_information_representation] is a [class_of_arranged_individual] that defines a pattern that represents information. EXAMPLE. The texts formed with the pattern of characters 's' concatenated with 'u' concatenated with 'n' are members of the 'sun' [class_of_information_representation]. 1 1 1 1 A [class_of_organization] is a [class_of_arranged_individual] whose members are instances of [physical_object] that are composed of temporal parts of people and other assets, and are organised with a particular purpose. EXAMPLE. Company, government, and project team can be represented by instances of [class_of_organization] A [phase] is a [class_of_arranged_individual] based on the nature of the boundary behaviour of material resulting from its atomic and molecular bonding. NOTE. [phase] excludes types of internal structure such as crystalline. EXAMPLE. The classes known as 'liquid' and 'solid' can be represented by instances of [phase]. An [actual_individual] is a [possible_individual] that is a part of the space-time continuum that we inhabit. It exists in the present, past, or future of our universe, as opposed to some imagined universe. NOTE. The things we plan can usually only be assumed to be part of some imagined universe, until they come about. EXAMPLE 1. The Eiffel Tower is an [actual_individual]. EXAMPLE 2. The computer used to edit this ontology is an [actual_individual]. EXAMPLE 3. The fictional character, Sherlock Holmes, is a [possible_individual] who is not an [actual_individual]. EXAMPLE 4. The Earth in the year 2300 (assuming it still exists) is an [actual_individual]. A [class_of_temporal_sequence] is a [class_of_relationship] where the sequence is of a temporal nature. EXAMPLE 1. The link that indicates that members of July follow members of June can be represented by an instance of [class_of_sequence]. EXAMPLE 2. The link that indicates that emptying activities for a tank precede cleaning activities can be represented by an instance of [class_of_sequence]. 1 1 A [class_of_event] is a [class_of_individual] whose members are members of [event]. EXAMPLE. Continuous and instantaneous are instances of [class_of_event]. A continuous event is one such as a stream boundary flowing through a pipe. A [class_of_scale_conversion] is a [class_of_isomorphic_functional_mapping] that defines a conversion between two different scales of units used for the quantification of properties. EXAMPLE. The Fahrenheit scale for temperature and the Celsius scale for temperature can each be represented by instances of [scale]. The conversion between these scales can be represented by an instance of [class_of_scale_conversion]. A [class_of_status] is a [class_of_class_of_individual] whose members are a [status]. EXAMPLE. An example of [class_of_status] is approval, with members: not assessed, approved, rejected. A [class_of_arranged_individual] is a [class_of_individual] whose members are an arrangement of components. EXAMPLE. Robocop is a [class_of_arranged_individual] that has some parts that are members of some [class_of_inanimate_physical_object] and parts that are members of some [class_of_organism]. 1 A [class_of_recognition] is a [class_of_relationship] that indicates that a member of a [class_of_activity] may result in the recognition of a member of a [class]. EXAMPLE A measurement activity may result in the recognition of the [classification] of a [possible_individual] by a [property]. 1 A [class_of_intended_role_and_domain] is a [class_of_relationship] that indicates that a member of the [class_of_individual] is intended to act as a member of the [role_and_domain]. EXAMPLE. Pumps are intended to play the [role_and_domain] of performer in some pumping activity. 1 1 A [class_of_individual] is a class whose members are instances of [possible_individual]. EXAMPLE. The class known as 'engineer', whose members are people qualified or skilled in engineering principles and practices can be represented by an instance of [class_of_individual]. 1 1 A [class_of_indirect_property] is a [class_of_relationship] that indicates that a member of the [class_of_individual] can possess a member of the [class_of_property] as an [indirect_property] of this type. EXAMPLE. Maximum Allowable Working Pressure is a [class_of_indirect_property] that is indicated by a pressure, and can be possessed by a pressure vessel. A [class_of_arranged_individual] is a [class_of_individual] whose members are an arrangement of components. EXAMPLE. Robocop is a [class_of_arranged_individual] that has some parts that are members of some [class_of_inanimate_physical_object] and parts that are members of some [class_of_organism]. NOTE 1. The ONEOF constraint on some of the subtypes does not prevent a particular [possible_individual] from being, say, a member of a particular [arranged_individual] classified by [class_of_biological_matter] and a member of a particular [class_of_composite_material]. It is only the classes themselves that are not members of more than one of the entity types. NOTE 2. Specifications or descriptions of useful objects are often intersections of several arrangement classes, allowing both shape and material aspects to be constrained. In this part of ISO 15926, such intersections are members of [class_of_arranged_individual], [class_of_feature], [class_of_inanimate_physical_object], [class_of_organization], [class_of_activity], [class_of_organism], or [class_of_information_object]. A [property_space] is a [class_of_property] whose members are a coherent continuum of [property]. EXAMPLE 1. The set of temperature properties, known as temperature, is a [property_space]. EXAMPLE 2. The members of the pressure and flow rate [class_of_property] that fall on a particular pump curve is a [property_space]. 1 1 1 1 1 1 1 1 A [class_of_functional_mapping] is a [class_of_relationship] that is a many to one mapping. A [class_of_functional_mapping] is a function. NOTE 1. This entity type would naturally have the name of function. NOTE 2. The significance of a function being a many to one mapping is that the same answer is always obtained. So, for example, 5 - 3 always gives 2. Note that the minus function on two other arguments can also give 2. NOTE 3. When there are several arguments to a function, then these are presented in a [multidimensional_object]. EXAMPLE. Minus is an example of [class_of_functional_mapping]. 1 1 A [class_of_representation_translation] is a [class_of_relationship] that indicates the translation of two instances of [class_of_information_representation]. EXAMPLE. The link that indicates that the representations 'F' and '15' are equivalent (concept of fifteen in hexadecimal and octal respectively) can be represented by an instance of [class_of_representation_translation]. A [crystalline_structure] is a [class_of_arranged_individual] that is a form in which many simple elements and their natural compounds regularly aggregate by the operation of natural affinity: it has a definite internal structure, with the external form of a solid enclosed by a number of symmetrically arranged plane faces, and varying in simplicity from the cube to much more complicated geometric bodies. EXAMPLE. Ferritic, martensitic, and austenitic are examples of [crystalline_structure]. A [class_of_representation_of_thing] is a [class_of_relationship] that indicates that all members of the pattern [class_of_information_representation] represent the [thing]. EXAMPLE. The [class_of_relationship] that indicates that occurrences of the pattern denoted by 'London' represent the concept of the capital of the United Kingdom can be represented by an instance of [class_of_information_representation]. 1 1 A [class_of_indirect_connection] is a [class_of_connection_of_individual] whose members are members of [indirect_connection]. EXAMPLE. Drip pipe indirectly connected to drain funnel is an example of [class_of_indirect_connection]. A [property_range] is a [property_space] that is a continuous subset of a [single_property_dimension]. EXAMPLE. -10C to +20C is a [property_range] of temperature. A [class_of_containment_of_individual] is a [class_of_relative_location] whose members are instances of [containment_of_individual]. It indicates that a member of the class_of_locator [class_of_individual] can contain a member of the class_of_located [class_of_individual]. EXAMPLE. That 'de-icing fluid' can be contained by a '1500ml screw-top plastic bottle' is a [class_of_containment_of_individual]. A [class_of_abstract_object] is a [class] whose members classify members of [abstract_object]. A [participating_role_and_domain] is a [role_and_domain] that is also a [class_of_individual] that indicates a participating role in an [activity]. EXAMPLE. Performer and pumper are examples of [participating_role_and_domain]. 1 A [property] is a [class_of_individual] that is a member of a continuum of a [class_of_property]. The [property] may be quantified by mapping to a number on a scale. NOTE 1. A member of a [property] is a [possible_individual] that has the same degree or magnitude of the quality or characteristic represented by the [property] as other members. NOTE 2. The types of characteristic or quality, such as temperature or density, are instances of [class_of_property]. NOTE 3. Duplicate properties (e.g. that map to the same number on the same scale) should not be created within the same data store. EXAMPLE. A particular degree of hotness can be represented as an instance of [property]. An <abstract_object> is a <thing> that does not exist in space-time. A [class_of_description] is a [class_of_representation_of_thing] that indicates the pattern is a description of the represented thing. EXAMPLE. The link between the pattern 'this is an old bilge pump' and a particular pump can be represented by an instance of [class_of_description]. A [class_of_EXPRESS_information_representation] is a [class_of_information_representation] that is defined by ISO 10303-11. 1 A [class_of_multidimensional_object] is a [class] whose members are instances of [multidimensional_object]. The role played by each position in the classified [multidimensional_object] is specified at the same position in the [roles] attribute. Constant values that apply to any position in [roles] are specified in the same position in the [parameters] attribute. The cardinalities for the roles attribute are specified by the same position in the cardinalities attribute. EXAMPLE. The definition of the input to a function y = a + bx to convert Celsius to Fahrenheit with roles [a, b, x] defining the input [multidimensional_object], and parameters [32,1.8] with parameter_position list [1,2] is an example of a [class_of_multidimensional_object]. 1 A [class_of_information_object] is a [class_of_arranged_individual] whose members are members of zero or more [class_of_information_representation] and of zero or more [class_of_information_presentation]. NOTE. Usually, it is a physical_object (like a paper document) that is classified as a [class_of_information_object]. EXAMPLE. Newspaper is a [class_of_information_object]. A [direct_connection] is a [connection_of_individual] that indicates that the two possible_individuals are directly connected via a common spatial boundary. EXAMPLE. The relation that indicates that the plug terminating a serial communications cable is connected to the socket on a piece of computer equipment can be represented by an instance of of [direct_connection]. A [possible_role_and_domain] is a [relationship] that indicates that a player [possible_individual] can possibly play the played [role_and_domain]. EXAMPLE Acting as an anchor is a possible role for pump 1234. NOTE (OWL). domain has the role of played, range has the role of player. A [beginning] is a [temporal_bounding] that marks the temporal start of a [possible_individual]. EXAMPLE 1 The relation that indicates that the [point_in_time] known as 0000hrs 1st July 1999 UTC is the beginning of the [period_in_time] known as July 1999 UTC can be represented by an instance of [beginning]. EXAMPLE 2 The relation that indicates that the [event] 'loading complete' marks the start of the [possible_individual] 'loading plant idle' can be represented by an instance of [beginning]. http://ompek.org#beginning A [difference_of_set_of_class] is a [functional_mapping] that indicates that the membership of the result [class] is the difference between the membership of the union of the classes that are members of the [enumerated_set_of_class] and their intersection. NOTE When the [enumerated_set_of_class] consists of a [class] and another [class] that is a subclass of the first class, then the difference is the complement of the subclass. EXAMPLE The difference of the [enumerated_set_of_class] {{A,B,C},{B,C,D},{C,D,E}} is {A,B,D,E}. http://ompek.org#difference_of_set_of_class http://ompek.org#containment_of_individual A [containment_of_individual] is a [relative_location] where the located [possible_individual] is contained by the locator [possible_individual] but is not part of it. EXAMPLE The contents of a vessel being inside the vessel can be represented by an instance of [containment_of_individual]. NOTE Containment is distinct from composition; in composition the whole consists of all of its part, with containment, what is contained is not a part of the container. A [representation_of_thing] is a [relationship] that indicates that a [possible_individual] is a sign for a [thing]. EXAMPLE The relationship between a nameplate with its serial number and other data, and a particular pressure vessel ([materialized_physical_object]) is an example of [representation_of_thing] that is an [identification]. NOTE In general it will be [class_of_representation_of_thing] that will be of interest, rather than each [representation_of_thing]. However, [representation_of_thing] will be of interest when individual copies of documents are managed and controlled. NOTE (OWL). domain has the role of represented, range has the role of sign. http://ompek.org#responsibility_for_representation A [responsibility_for_representation] is a [relationship] that indicates that the controller [possible_individual] administers the controlled [representation_of_thing]. EXAMPLE The responsibility for the administration of this standard lies with ISO. http://ompek.org#arrangement_of_individual An [arrangement_of_individual] is a [composition_of_individual] that indicates that the part is a part of an [arranged_individual]. The temporal extent of the part is that of the whole. An [arrangement_of_individual] may be an [assembly_of_individual]. NOTE 1 The term "arranged" implies that parts have particular roles with respect to the whole. NOTE 2 The natures of the relations to other parts of the whole are not specified by the arrangement relation. Relationships like [connection_of_individual] and [relative_location] would indicate this. EXAMPLE 1 The relationship that indicates that a particular aircraft is flying as part of a formation can be represented by an instance of [arrangement_of_individual]. EXAMPLE 2 The relationship that indicates that a particular bin in a warehouse is part of the warehouse layout can be represented by an instance of [arrangement_of_individual]. A [cause_of_event] is a [relationship] that indicates that the caused [event] is caused by the causer [activity]. EXAMPLE The relation that indicates that the tanker loading activity caused the [event] described as 'tank liquid level full' can be represented by an instance of [cause_of_event]. NOTE (OWL). domain has the role of event, range has the role of activity. A [participation] is a [composition_of_individual] that indicates that a [possible_individual] is a participant in an [activity]. NOTE The [possible_individual] that is the part in the [participation] is may be a temporal part of a [whole_life_individual] that is classified by the [role_and_domain] that indicates the role it plays in the [activity]. EXAMPLE The relationship between the temporal part of P1234 that performs the discharge of the Motor Vessel Murex on 2nd December 2002, and the activity that is that discharge of that vessel is a [participation]. http://ompek.org#participation A [feature_whole_part] is an [arrangement_of_individual] that indicates that the part is a non-separable, contiguous part of the whole. NOTE This includes wholes that cannot be non-destructively disassembled and reassembled such as the cast inlet flange of a pump. EXAMPLE The relation that indicates that a flange face is part of a flange can be represented by an instance of [feature_whole_part]. http://ompek.org#feature_whole_part http://ompek.org#assembly_of_individual An [assembly_of_individual] is an [arrangement_of_individual] that indicates that the part is connected directly or indirectly to other parts of the whole. The parts and wholes are super-molecular objects. NOTE Composition of molecules and smaller is represented through instances of class_of_arrangement_of_individual. EXAMPLE The relation that indicates that a temporal part of an impeller is a part of an assembled pump can be represented by an instance of [assembly_of_individual]. http://ompek.org#approval An [approval] is a [relationship] that indicates that a [relationship] has been approved by a [possible_individual] that is an approver. NOTE Care should be taken as to what is approved. Sometimes it will not be say a pump that is approved, but the participation of the pump in a particular [activity], or member of some [class_of_activity]. EXAMPLE The [involvement_by_reference] of a plant design with a construction activity, being approved by the site manager, is an example of an [approval]. A [connection_of_individual] indicates that matter, energy, or both can be transferred between the members of [possible_individual] that are connected, either directly or indirectly. NOTE. There is no significance to the ordering of the two related instances of [possible_individual]. A [temporal_sequence] is a [relationship] that indicates that one [possible_individual] precedes another in a temporal sense. EXAMPLE 1 The [relationship] that indicates that the [possible_individual] that is the construction phase of a plant precedes the [possible_individual] that is the commissioning phase of a plant can be represented by an instance of [temporal_sequence]. EXAMPLE 2 The [relationship] that indicates that the [period_in_time] known as the industrial revolution preceded the [period_in_time] known as the information revolution can be represented by an instance of [temporal_sequence]. NOTE (OWL). domain has the role of predecessor, range has the role of successor. A [recognition] is a [relationship] that indicates that a [thing] is recognized through an [activity]. EXAMPLE Measurement activity #358 recognized that the room was a member of the 20 Celsius [property]. NOTE (OWL). domain has the role of recognized, range has the role of recognizing. http://ompek.org#definition A [definition] is a [representation_of_thing] that indicates that the [class] is defined by the sign [possible_individual]. EXAMPLE The [relationship] between this copy of the preceding sentence and the heading before that is a [definition]. An [involvement_by_reference] is a [relationship] that indicates that a [thing] is referred to in an [activity]. NOTE This property is for involvements that are not direct [participation] of a [possible_individual], such as involvement of a class, or of a historical or future temporal part of a [possible_individual]. EXAMPLE A conversation that refers to the Roman Empire is an [activity] that relates to the Roman Empire by an [involvement_by_reference]. NOTE (OWL). domain has the role of involved (thing), range has the role of involver (activity). An [intersection_of_set_of_class] is a [functional_mapping] that indicates that the result [class] consists of those members of the members of the classes [enumerated_set_of_class] that are common to each class. EXAMPLE The intersection of the [enumerated_set_of_class] {{A,B,C},{B,C,D},{C,D,E}} is {C}. http://ompek.org#intersection_of_set_of_class A [temporal_whole_part] is a [composition_of_individual] that indicates that one [possible_individual] is a temporal part of another [possible_individual]. The spatial extent of the temporal part is that of the temporal whole for the period of the existence of the temporal part. Relationships that apply to the whole [possible_individual] also apply to the temporal parts of the [possible_individual], except when the relationships relate to the temporal nature of the whole. So if a [possible_individual] is connected so are all its temporal parts, but being a [whole_life_individual] is not inherited by its temporal parts. NOTE Since [temporal_whole_part] is transitive (inherited from its supertype) a hierarchy of temporal parts is possible, with a [whole_life_individual] at the top. EXAMPLE 1 The relation that indicates that an operating period of a pump is a temporal part of the pump can be represented by an instance of [temporal_whole_part]. EXAMPLE 2 The relationship that indicates that the time period known as March 1999 is part of the period known as 1st Quarter 1999 can be represented by an instance of [temporal_whole_part]. http://ompek.org#temporal_whole_part An [intended_role_and_domain] is a [relationship] that indicates the [role_and_domain] some temporal part of the [possible_individual] is intended to take with respect to some [activity]. EXAMPLE Some [possible_individual] that is classified as a pump is intended to play the [role_and_domain] of a performer in some pumping activity. NOTE (OWL). domain has the role of played, range has the role of player. A [temporal_bounding] is a [composition_of_individual] that indicates that the part [event] is a temporal boundary of the whole [possible_individual]. http://ompek.org#temporal_bounding A [usage_of_representation] is a [relationship] that indicates that the [representation_of_thing] is used by the [possible_individual]. Usage does not imply responsibility. EXAMPLE The sign "P101" is used by the XYZ company to represent a particular pump in a design. NOTE (OWL). domain has the role of used, range has the role of user. http://ompek.org#usage_of_representation http://ompek.org#individual_used_in_connection An [individual_used_in_connection] is a [relationship] that indicates that a [possible_individual] is used in a [connection_of_individual]. EXAMPLE The [relationship] between the connection of the flanged ends of two pipes and a temporal part of the bolts, nuts, washers and gasket set that indicates that the bolt and gasket set participates in the connection can be represented by an instance of [individual_used_in_connection]. http://ompek.org#functional_mapping A [functional_mapping] is a [relationship] that indicates that the input gave the result as determined by the classifying [class_of_functional_mapping]. EXAMPLE The mapping of [5, 3] to 2, classified by the minus function is an example of [functional_mapping]. NOTE (OWL): domain has the role of input, range has the role of result. http://ompek.org#identification An [identification] is a [representation_of_thing] that indicates that the [possible_individual] is an identifier for the [thing] identified. EXAMPLE 1 The relationship between the text "P101" on a printed copy of a pump data sheet and the applicable [functional_physical_object] is an example of [identification]. EXAMPLE 2 The relationship between a name tag and an employee wearing it is an example of [identification]. An [upper_bound_of_number_range] is a [relationship] that indicates an [arithmetic_number] is the largest value in a [number_range]. EXAMPLE 5.3 is the upper bound of the range [3.1 to 5.3]. http://ompek.org#upper_bound_of_number_range http://ompek.org#upper_bound_of_property_range An [upper_bound_of_property_range] is a [class_of_classification] that indicates that the [property] is the upper bound of the [property_range]. EXAMPLE +20 Celsius is the upper bound of the range -10 to +20 Celsius. http://ompek.org#description A [description] is a [representation_of_thing] that indicates that the [possible_individual] describes the [thing]. EXAMPLE A copy of the Piping and Instrumentation Diagram for Crude Distillation Unit 1 at refinery X has a [description] relationship with the plant. http://ompek.org#ending An [ending] is a [temporal_bounding] that marks the end of a [possible_individual]. EXAMPLE 1 The relation that indicates that the [point_in_time] known as 0000hrs 1st July 1999 GMT is the end of the [period_in_time] known as June 1999 GMT can be represented by an instance of [ending]. EXAMPLE 2 The relation that indicates that the [event] 'loading complete' marks the end of the [possible_individual] 'loading plant operating period 1' (a temporal part of the loading plant) is an instance of [ending]. A [composition_of_individual] is a [relationship] that indicates that the part [possible_individual] is a part of the whole [possible_individual]. A simple composition is indicated, unless a subtype is instantiated too. [composition_of_individual] is transitive. NOTE Simple composition means that for example no arrangement of parts is necessarily implied or of concern. Where there is an arrangement of parts, this is indicated by an [arrangement_of_individual], which, by being a subtype, implies also a simple composition. EXAMPLE A grain of sand being part of a pile of sand is an example of [composition_of_individual]. NOTE (OWL): domain has the role of whole; range has the role of part. http://ompek.org#composition_of_individual A [comparison_of_property] is a [relationship] that indicates the magnitude of one [property] is greater than that of another. EXAMPLE That the temperature in a room is less than that in a furnace can be indicated by an instance of [comparison_of_property]. NOTE (OWL). domain has the role of greater_element, range has the role of lesser_element. http://ompek.org#comparison_of_property An [indirect_property] is a [relationship] between a [property] and a [possible_individual]. The nature of the [indirect_property] is defined by its [classification] by a [class_of_indirect_property]. A property is indirect when it does not directly apply to the [possible_individual] it applies to, but is derived from some process. NOTE A property is indirect because it does not directly apply. There can only be one temperature that a thing has (at a time), so a Maximum Allowable Working Temperature is not its temperature, but an indirect property derived from doing some tests or calculations to determine its value (as opposed to it being a current measurement). This is what makes it indirect. EXAMPLE A Maximum Allowable Working Pressure of 50 BarA for V101 is specified by an [indirect_property] between the pressure of 50 BarA and V101, classified by the [class_of_indirect_property] Maximum Allowable Working Pressure. NOTE (OWL). domain has the role of possessor, range has the role of property. A [classification] is type of [relationship] that indicates that the classified [thing] is a member of the classifier [class]. [classification] is not transitive. NOTE A subtype of [relationship] is transitive if when A is related to B, and B is related to C in the same way, then A is necessarily related to C in that way. [specialization] and [composition] are examples of transitive subtypes of [relationship]. However, because [classification] is not transitive does not mean that A cannot be related to C in the same way, only that it does not necessarily follow from A being related to B and B being related to C. EXAMPLE 1 The [relationship] that indicates that London is a member of the class known as 'capital city' is a [classification]. EXAMPLE 2 The [relationship] that indicates that 'pump' is a member of the class 'equipment type' is a [classification]. NOTE (OWL). domain has the role of classified, range has the role of classifier. A [specialization] is a [relationship] that indicates that all members of the subclass are members of the superclass. [specialization] is transitive. NOTE If A is a [specialization] of B and B is a [specialization] of C, then A is necessarily a [specialization] of C. EXAMPLE Centrifugal pump is a [specialization] of pump. NOTE (OWL). domain has the role of subclass and range has the role of superclass. http://ompek.org#indirect_connection An [indirect_connection] is a [connection_of_individual] that indicates that side_1 and side_2 are connected via other individuals. EXAMPLE The relation that indicates that there is a railway connection between the cities of London and Paris can be represented by an instance of [indirect_connection]. http://ompek.org#lower_bound_of_property_range A [lower_bound_of_property_range] is a [class_of_classification] that indicates that a [property] is the lower bound of a [property_range]. EXAMPLE -10 Celsius is the lower bound of the range -10 to +20 Celsius. A [lifecycle_stage] is a [relationship] that indicates the interest that a [possible_individual] has in some [possible_individual]. EXAMPLE The relation that links a possible building to a temporal part of the XYZ Corp. can be represented by an instance of [lifecycle_stage]. The nature of that [lifecycle_stage] (e.g. 'planned') can be expressed by classifying with the applicable [class_of_lifecycle_stage]. NOTE (OWL). domain has the role of interest, range has the role of interested. A [lower_bound_of_number_range] is a [relationship] that indicates an [arithmetic_number] is the lowest value in a [number_range]. EXAMPLE 3.1 is the lower bound of the range [3.1 to 5.3]. http://ompek.org#lower_bound_of_number_range http://ompek.org#property_quantification A [property_quantification] is a [functional_mapping] whose members map a [property] to an [arithmetic_number]. EXAMPLE The link that maps a particular mass to the number 4.2 can be represented by an instance of [property_quantification]. NOTE 1 The actual representation of the number is done by linking the [arithmetic_number] to a [class_of_EXPRESS_information_representation] via a [class_of_representation_of_thing]. NOTE 2 The unit or scale of the quantification is given by classifying the [property_quantification] by a [scale]. http://ompek.org#union_of_set_of_class A [union_of_set_of_class] is a [functional_mapping] that indicates that the membership of the result [class] is the union of the members of the [enumerated_set_of_class] classes. EXAMPLE The union of the [enumerated_set_of_class] {{A,B,C},{B,C,D},{C,D,E}} is {A,B,C,D,E}. A [relative_location] is a [relationship] that indicates that the position of one [possible_individual] is relative to another. NOTE. In the EXPRESS version, the [classification] of the [relative_location] indicates the nature of the [relative_location], e.g. above, below, beside. EXAMPLE: A being the located relative to B being the locator in a [relative_location] that is classified by the [class_of_relative_location] above, indicates that A is above B. In this ontology above, below, etc. are user-defined subclasses of relative_location. NOTE (OWL). domain has the role of located, range has the role of locator.