Snippets (text quotes and extracts from authoritative sources)

A Snippet is a short quote or extract (typically a phrase, a sentence, or at most a few sentences) from an authoritative source document such as a specification, technical manual, or design manual. Throughout this site, content is often related to supporting Snippets and each Snippet page links back to the content pages that reference it! The Snippet and Note concepts are very closely related and they support each other.

The Snippet concept is also at the heart of the Parsing Analysis recipe for UML® and SysML®

Kind Snippet quote/extract Source UML keywords SysML keywords Keywords
NOTATION On Communication Diagrams, the Messages are decorated by a small arrow in the direction of the Message close to the Message name and sequence number along the line between the lifelines ... OMG Systems Modeling Language (SysML) 1.6 Message, MessageEnd, Communication Diagram, Lifeline
INFO On [a] psychrometric chart, this process is represented as [a] line sloping downward and to the left. This process is assumed to occur as simple cooling first and then condensation. While the moisture is condensing the air is assumed to remain saturated. CED Engineering course PDF: 'Air Conditioning Psychrometrics (A.Bhatia)' thermodynamics, Psychrometrics, humid air, temperature, dry bulb temperature, wet bulb temperature, relative humidity, absolute humidity, sensible heat, heat, energy, energy transfer, cooling
INFO Once the test fails and the loop is completed, the tokens on the bodyOutput OutputPins from the last iteration are moved to the result OutputPins and offered on any edges outgoing from those OutputPins. Unified Modeling Language 2.5.1 Activity, Activity Diagram, LoopNode, LoopNode::loopVariable, OutputPin, LoopNode::bodyOutput
INFO, NOTATION One can label an ItemFlow with the classifiers of the items that may be conveyed. For example: a label Water would imply that instances of Water might be transmitted over this ItemFlow. OMG Systems Modeling Language (SysML) 1.6 InformationFlow ItemFlow
INFO One or more argument values may be posted to a streaming input Parameter at or any time after the invocation of a Behavior and before its completion. These argument values are then available to affect the further course of the Behavior execution ... Unified Modeling Language 2.5.1 Behavior, Parameter::isStreaming, Parameter, execution, ParameterDirectionKind::in
INFO One or more protons are present in the nucleus of every atom; they are a necessary part of the nucleus. Wikipedia
INFO One or more result values may be posted to a streaming output Parameter any time after the invocation of a Behavior up to or at its completion. These result values are then available to affect the further course of the execution of the invoking Behavior.. Unified Modeling Language 2.5.1 Behavior, Parameter::isStreaming, Parameter, execution, ParameterDirectionKind::out
INFO Optical radiation is part of the electromagnetic spectrum. It is subdivided into ultraviolet radiation (UV), the spectrum of light visible for man (VIS) and infrared radiation (IR). It ranges between wavelengths of 100 nm to 1 mm [DISPUTED] Wikipedia optical radiation, optical astronomy, optics, [DISPUTED]
INFO Optionally, members of an element group can be ordered using its orderedMember property. OMG Systems Modeling Language (SysML) 1.6 Comment ElementGroup, ElementGroup::/member, ElementGroup::orderedMember
INFO Originally, the only symbol for the litre was l (lowercase letter L), following the SI convention that only those unit symbols that abbreviate the name of a person start with a capital letter. Wikipedia litre, units, scientific unit system, volume, SI unit, SI alternative unit, ISO-80000
INFO Otherwise, the appropriate history entry into the Region is executed (see above). If no default history Transition is defined, then standard default entry of the Region is performed .... Unified Modeling Language 2.5.1 State, StateMachine, Vertex, Pseudostate, history, PseudostateKind::deepHistory, PseudostateKind::shallowHistory, default history mechanism
INFO Parameters may also be marked as streaming (i.e., have the isStreaming property be true). Such Parameters allow values to be passed into and out of a Behavior execution any time during its course, rather than just on invocation and completion. Unified Modeling Language 2.5.1 Behavior, Parameter::isStreaming, Parameter, execution
INFO parametric diagrams can make use of the nested property name notation to refer to multiple levels of nested property containment, as shown in this example. OMG Systems Modeling Language (SysML) 1.6 ConstraintBlock, constraint property, SysML Parametric Diagram, nested Property, multi-level property path
INFO Parametric diagrams include usages of constraint blocks to constrain the properties of another block. OMG Systems Modeling Language (SysML) 1.6 Constraint ConstraintBlock, SysML Parametric Diagram mathematics, equation
INFO Part properties, typed by blocks ... represent components in this system. They are connected to each other through ports, which represent openings in the tanks and pipe ... SysPhS-1.1 Connector, Port part property, Block, "standard" Port SysPhS, hydraulics
INFO Part properties, typed by blocks ... represent the components of the system. They are connected through ports .. which represent signal outputs and inputs ... SysPhS-1.1 Port Block, part property, "standard" Port SysPhS, signal processing
INFO Part, reference, value, and constraint properties may be shown in block definition compartments with the labels "parts," "references," "values," and "constraints" respectively. OMG Systems Modeling Language (SysML) 1.6 Property Block, value property, MD:ValueProperty, reference property, MD:ReferenceProperty, constraint property, MD:ConstraintProperty, parts compartment, references compartment, values compartment, constraints compartment
CONSTRAINT PhSConstant: [1] Properties stereotyped by PhSConstant must be typed by Real, Integer, or Boolean, or one of their specializations. SysPhS-1.1 Real, Integer, Boolean SysPhS, SysML, Systems Modeling Language
CONSTRAINT PhSConstant: [2] Properties stereotyped by PhSConstant must have multiplicity 1, unless they are also stereotyped by MultidimensionalElement (see Subclause 11.5). SysPhS-1.1 SysPhS, SysML, Systems Modeling Language
CONSTRAINT PhSConstant: [3] Properties stereotyped by PhSConstant must not redefine more than one other property, which must have the same name and type and must be stereotyped by PhSVariable or PhSConstant. SysPhS-1.1 Property::redefinedProperty SysPhS, SysML, Systems Modeling Language
CONSTRAINT PhSVariable: [1] The stereotyped property must be typed by Real, Integer, or Boolean, or one of their specializations. SysPhS-1.1 Real, Integer, Boolean SysPhS, SysML, Systems Modeling Language
CONSTRAINT PhSVariable: [2] isContinuous may be true only when the stereotyped property is typed by Real or one of its specializations. SysPhS-1.1 Real SysPhS, SysML, Systems Modeling Language
CONSTRAINT PhSVariable: [3] isConserved may be true only when isContinuous is true and the stereotyped property is on a block specialized from ConservedQuantityKind (see Subclause 11.2.2). SysPhS-1.1 SysPhS, SysML, Systems Modeling Language
CONSTRAINT PhSVariable: [4] changeCycle may be other than 0 only when isContinuous is false. SysPhS-1.1 SysPhS, SysML, Systems Modeling Language
CONSTRAINT PhSVariable: [5] changeCycle must be positive or 0. SysPhS-1.1 SysPhS, SysML, Systems Modeling Language
INFO Pins are used to specify the inputs and outputs for Actions. Unified Modeling Language 2.5.1 Activity, Activity Diagram, Action, Pin, InputPin, OutputPin, Action::/input, Action::/output
INFO Pins for control parameters are regular pins, not UML control pins. This is so the control value can be passed into or out of the action and the invoked behavior, rather than control the starting of the action, or indicating the ending of it. OMG Systems Modeling Language (SysML) 1.6 Behavior, Operation, Pin ControlOperator, ControlValueKind
INFO, NOTATION Port labels appear in the same format as properties on the end of an association. Port labels can appear inside port rectangles. OMG Systems Modeling Language (SysML) 1.6 Port, label, NamedElement::name, Type
INFO, NOTATION Port rectangles can have port rectangles overlapping their boundaries, to notate a port type that has ports (nested ports). OMG Systems Modeling Language (SysML) 1.6 Port nested Port
INFO Ports appearing in block compartments can have their direction appear textually before the port name as “in,” “out,” or “inout” determined in the same way as the arrow direction. OMG Systems Modeling Language (SysML) 1.6 Port ProxyPort, FullPort, FlowProperty, FlowProperty::direction, FlowDirectionKind::in, FlowDirectionKind::out, FlowDirectionKind::inout, nested Port
INFO Ports are a special class of property used to specify allowable types of interactions between blocks ... OMG Systems Modeling Language (SysML) 1.6 Property, Port, ports compartment Block, block property systems engineering, Model-Based Systems Engineering, SysML, Systems Modeling Language
INFO, NOTATION Ports are notated by rectangles overlapping the boundary of their owning blocks or properties (parts or ports) typed by the owning block. OMG Systems Modeling Language (SysML) 1.6 Port
NOTATION Ports are special cases of properties, and have a variety of notations ... OMG Systems Modeling Language (SysML) 1.6 Property, Port part property, MD:PartProperty
INFO, NOTATION Ports are specialized kinds of properties, and can be shown in same way as other properties. They can appear in block compartments in the same format as other properties of their owning blocks, or as the ends of associations, with the port appearing ... OMG Systems Modeling Language (SysML) 1.6 Port, compartment, Property, Association, Association::memberEnd, Association::ownedEnd nested Port, block compartment
INFO Ports nest other ports in the same way that blocks nest other blocks. The type of the port is a block (or one of its specializations) that also has ports. OMG Systems Modeling Language (SysML) 1.6 Port nested Port
INFO, NOTATION Ports that are not proxy or full can appear in block compartments labeled ports. OMG Systems Modeling Language (SysML) 1.6 Port, compartment, ports compartment nested Port, block compartment
INFO Ports that are not specified as proxy or full are simply called “ports.” OMG Systems Modeling Language (SysML) 1.6 Port
INFO Ports with types that have flow properties all in the same direction, either all in or all out, can have an arrow inside them indicating the direction of the properties with respect to the owning block. OMG Systems Modeling Language (SysML) 1.6 Port ProxyPort, FullPort, FlowProperty, FlowProperty::direction, FlowDirectionKind::in, FlowDirectionKind::out
INFO Ports with types that have flow properties in different directions or flow properties that are all in both directions, including have two open arrow heads inside them facing away from each other (<>). This includes the directions of nested and... OMG Systems Modeling Language (SysML) 1.6 Port ProxyPort, FullPort, FlowProperty, FlowProperty::direction, FlowDirectionKind::in, FlowDirectionKind::out, FlowDirectionKind::inout, nested Port
INFO Positronium (Ps) is a system consisting of an electron and its anti-particle, a positron, bound together into an exotic atom, specifically an onium. Wikipedia
INFO Precise measurements show that the boiling point of VSMOW water under one standard atmosphere of pressure is actually 373.1339 K (99.9839 °C) when adhering strictly to the two-point definition of thermodynamic temperature. Wikipedia thermodynamics, temperature, celsius, kelvin, Kelvins, water, boiling point
INFO Properties of any type may be shown in a "properties" compartment or in additional compartments with user-defined labels. OMG Systems Modeling Language (SysML) 1.6 Property, compartment Block, properties compartment
INFO Properties with AdjunctProperty applied, where the principal of the AdjunctProperties are call actions, including call behavior actions, can be used as the part end of the associations. See 8.3.2.2 for constraints when AdjunctProperty is used ... OMG Systems Modeling Language (SysML) 1.6 Property, CallBehaviorAction, Association, Association::ownedEnd, Activity SysML Block Definition Diagram, Block, AdjunctProperty functional allocation, functional decomposition
EXAMPLE Properties with AdjunctProperty applied, where the principal of the AdjunctProperty is a parameter of the interaction, can be used as the end of the associations towards the parameter type. OMG Systems Modeling Language (SysML) 1.6 Interaction, Association, Parameter «interaction», SysML Block Definition Diagram, AdjunctProperty
INFO Properties with AdjunctProperty applied, where the principal of the AdjunctProperty is a parameter of the state machine, can be used as the end of the associations towards the parameter type. OMG Systems Modeling Language (SysML) 1.6 StateMachine, Association, Parameter SysML Block Definition Diagram, AdjunctProperty, AdjunctProperty::principal
INFO Properties with AdjunctProperty applied, where the principal of the AdjunctProperty is a submachine state, can be used as the end of the associations towards the sub state machine. OMG Systems Modeling Language (SysML) 1.6 StateMachine, Association, submachine SysML Block Definition Diagram, AdjunctProperty, AdjunctProperty::principal
EXAMPLE Properties with AdjunctProperty applied, where the principal of the AdjunctProperty is an interaction use, can be used as the end of the associations towards the interaction being used. OMG Systems Modeling Language (SysML) 1.6 Interaction, Property, Association, Association::memberEnd «interaction», SysML Block Definition Diagram, AdjunctProperty
INFO Properties with AdjunctProperty applied, where the principal of the AdjunctProperty is an object node, variable, or parameter, can be used as the end of the associations toward the object node, variable, or parameter type. OMG Systems Modeling Language (SysML) 1.6 Association, Classifier, ObjectNode, Variable, Parameter Block, ValueType, SysML Block Definition Diagram, AdjunctProperty, AdjunctProperty::principal
INFO Property is indirectly a kind of RedefinableElement, so Properties may be redefined. The name and visibility of a Property are not required to match those of any Property it redefines. Unified Modeling Language 2.5.1 Property, Property::redefinedProperty, NamedElement, NamedElement::name, VisibilityKind, NamedElement::visibility, RedefinableElement
INFO Property::defaultValue : ValueSpecification [0..1] Specifies a ValueSpecification that represents a value to be used when no argument is supplied for the Parameter. Unified Modeling Language 2.5.1 Property, Property::defaultValue, ValueSpecification UML, Unified Modeling Language
INFO Property::isDerivedUnion : Boolean [1..1] = false Specifies whether the property is derived as the union of all of the Properties that are constrained to subset it. Unified Modeling Language 2.5.1 Property, Property::isDerivedUnion
INFO Property::subsettedProperty : Property [0..*] ... The properties of which this Property is constrained to be a subset, if any. Unified Modeling Language 2.5.1 Property, Property::subsettedProperty
INFO Protons and neutrons are both nucleons, which may be bound together by the nuclear force to form atomic nuclei. Wikipedia
INFO Protons and neutrons constitute the nuclei of atoms. Wikipedia neutron
INFO Protons and neutrons, each with masses of approximately one atomic mass unit, are collectively referred to as "nucleons" (particles present in atomic nuclei). Wikipedia
INFO Protons are composite particles composed of three valence quarks: two up quarks of charge + 2/3e and one down quark of charge –1/3e. Wikipedia
INFO Protons are spin-1/2 fermions and are composed of three valence quarks, making them baryons (a sub-type of hadrons). Wikipedia
INFO Provided behavioral features are invoked with the owning block as target, while required behavioral features are invoked with an external block as target (required). OMG Systems Modeling Language (SysML) 1.6 Feature, BehavioralFeature, Operation, Reception DirectedFeature, FeatureDirectionKind::provided, FeatureDirectionKind::required, block property, value property, MD:ValueProperty, Block
INFO Provided non-flow properties are read and written on the owning block, while required non-flow properties are read or written on an external block OMG Systems Modeling Language (SysML) 1.6 Property, Feature DirectedFeature, FeatureDirectionKind::provided, FeatureDirectionKind::required, block property, value property, MD:ValueProperty
INFO Proxy and full ports support the capabilities of ports in general, but these capabilities are also available on ports that are not declared as proxy or full. OMG Systems Modeling Language (SysML) 1.6 Port FullPort, "standard" Port, ProxyPort
INFO Proxy ports are always typed by interface blocks, a specialized kind of block that has no behaviors or internal parts. OMG Systems Modeling Language (SysML) 1.6 Port ProxyPort, InterfaceBlock, ~InterfaceBlock
INFO Proxy ports can be connected to internal parts or ports on internal parts, identifying features on those parts or ports that are available to external blocks. OMG Systems Modeling Language (SysML) 1.6 Port, part, Feature ProxyPort, part property, MD:PartProperty
INFO Proxy ports define the boundary by specifying which features of the owning block or internal parts are visible through external connectors, while full ports define the boundary with their own features. OMG Systems Modeling Language (SysML) 1.6 Port ProxyPort, FullPort
INFO Proxy ports do not specify their own behaviors or internal parts, and shall be typed by interface blocks. Their nested ports shall also be proxy ports. OMG Systems Modeling Language (SysML) 1.6 Port, Behavior, part ProxyPort, InterfaceBlock, nested Port, part property
INFO Proxy ports identify features of the owning block or its internal parts that are available to external blocks through external connectors to the ports. They do not specify a separate element of the system from the owning block or internal parts. OMG Systems Modeling Language (SysML) 1.6 internal part, external Connector, Feature, Connector Connector, external Connector, ProxyPort
CONSTRAINT ProxyPort::1_not_fullport Proxy ports shall not also be full ports. This applies even if some of the stereotypes are on subsetted or redefined ports. OMG Systems Modeling Language (SysML) 1.6 Property::redefinedProperty, Property::subsettedProperty ProxyPort
CONSTRAINT ProxyPort::2_interfaceblock Proxy ports shall only be typed by interface blocks. OMG Systems Modeling Language (SysML) 1.6 ProxyPort, InterfaceBlock
CONSTRAINT ProxyPort::3_subports_are_proxyports Ports owned by the type of a proxy port shall be proxy ports. OMG Systems Modeling Language (SysML) 1.6 ProxyPort, nested Port
INFO quantityKind : InstanceSpecification [0..1] A kind of quantity, represented by an InstanceSpecification classified by a kind of SysML QuantityKind, that may be stated by means of units. A value type may optionally specify a quantity kind without any unit. OMG Systems Modeling Language (SysML) 1.6 ValueType, ValueType::quantityKind, QuantityKind
INFO QuantityKind is defined as a non-abstract SysML Block defined in the SysML UnitAndQuantityKind model library. OMG Systems Modeling Language (SysML) 1.6 QuantityKind, Unit, Unit::quantityKind, ValueType::quantityKind scientific unit system
INFO QuantityKind, or a specialization of it, classifies an InstanceSpecification to define a particular "kind-of-quantity" in the sense of an "aspect common to mutually comparable quantities" [VIM3-1.2], ... OMG Systems Modeling Language (SysML) 1.6 QuantityKind, Unit, Unit::quantityKind, ValueType::quantityKind scientific unit system
INFO Quarks ... are the only elementary particles in the Standard Model of particle physics to experience all four fundamental interactions, also known as fundamental forces (electromagnetism, gravitation, strong interaction, and weak interaction). Wikipedia
INFO Quarks ... are the only known particles whose electric charges are not integer multiples of the elementary charge. Wikipedia
INFO Quarks are fermionic particles of spin 1/2 (S = 1/2). Wikipedia
INFO Quarks combine to form composite particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nuclei. Wikipedia
INFO Quarks have various intrinsic properties, including electric charge, mass, color charge, and spin. Wikipedia
INFO Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around 20 kHz to around 300 GHz. Wikipedia radio astronomy, radio frequency, RF
INFO Rate ... It does not refer to the rate at which a value changes over time. OMG Systems Modeling Language (SysML) 1.6 value Rate, «rate»
INFO Rate ... When the stereotype is applied to a parameter, the parameter shall be streaming, and the stereotype gives the number of objects or values that flow in or out of the parameter per time interval while the behavior or operation is executing. OMG Systems Modeling Language (SysML) 1.6 Parameter, object token, value, Behavior, Operation, Parameter::isStreaming Rate, «rate» flow, time
CONSTRAINT Rate::rate - In particular, the denominator for units used in the rate property shall be time units. OMG Systems Modeling Language (SysML) 1.6 InstanceSpecification Rate, «rate», Rate::rate time
INFO rays that enter the system parallel to the optical axis are focused such that they pass through the rear focal point Wikipedia optics, principal plane, optic axis, focal point, focal length
INFO RealInSignalElement has an in flow property rsig, while RealOutSignalElement has the same property with an out direction. SysPhS-1.1 Port "standard" Port SysPhS
NOTATION Receptions are shown in the receptions compartment using the same notation as for Operations with the keyword «signal». Unified Modeling Language 2.5.1 Reception
INFO Refine::getRefines (in ref : NamedElement) : AbstractRequirement [0..*] The query getRefines() gives all the requirements that are suppliers ("to"end of the concrete syntax) of a «Refine» relationships whose client is the element in parameter ... OMG Systems Modeling Language (SysML) 1.6 query Refine, Refine::getRefines(in ref : NamedElement)
INFO Regardless of how a State is entered, the StateMachine is deemed to be “in” that State even before any entry Behavior or effect Behavior (if defined) of that State start executing. Unified Modeling Language 2.5.1 State, StateMachine, Transition, State::entry, State::exit, active state configuration, state configuration
INFO Regardless of how a State is exited, the StateMachine is deemed to have “left” that State only after the exit Behavior (if defined) of that State has completed execution. Unified Modeling Language 2.5.1 State, StateMachine, Behavior, State::exit
SEMANTIC Reinserting an existing value at a new position in an ordered, unique StructuralFeature moves the value to that position (this works because such StructuralFeature values are ordered sets). Unified Modeling Language 2.5.1 StructuralFeature, AddStructuralFeatureValueAction, StructuralFeatureAction, AddStructuralFeatureValueAction::insertAt, MultiplicityElement::isOrdered, MultiplicityElement::isUnique
INFO René François Ghislain Magritte was a Belgian surrealist artist. He became well known for creating a number of witty and thought-provoking images. Wikipedia
INFO Required and provided features are operations, receptions, and non-flow properties that a block supports for other blocks to use, or requires other blocks to support for its own use, or both. OMG Systems Modeling Language (SysML) 1.6 Feature, Operation, Reception, Property DirectedFeature, FeatureDirectionKind, FeatureDirectionKind::provided, FeatureDirectionKind::required, FeatureDirectionKind::providedrequired, value property
INFO Required Interfaces specify services that a BehavioredClassifier needs in order to perform its function and fulfill its own obligations to its clients. Unified Modeling Language 2.5.1 BehavioredClassifier, Interface, Usage, required Interface
INFO Requirements are used to establish a contract between the customer (or other stakeholder) and those responsible for designing and implementing the system. OMG Systems Modeling Language (SysML) 1.6 Requirement, «system» requirements engineering, contract, customer, stakeholder, designer
INFO Restrictions on the rate at which entities flow along edges in an activity, or in and out of parameters of a behavior (see Rate in Figure 11-8). This includes both discrete and continuous flows, either of material, energy, or information. OMG Systems Modeling Language (SysML) 1.6 «continuous», Continuous, Discrete, Rate, «discrete» continuous system, material, energy, information, flow
INFO Reusable constraint definitions may be specified on block definition diagrams and packaged into general-purpose or domain-specific model libraries. Such constraints can be arbitrarily complex mathematical or logical expressions. OMG Systems Modeling Language (SysML) 1.6 Constraint ConstraintBlock, MD:ConstraintParameter, constraint parameter, SysML Block Definition Diagram mathematics, equation
CONSTRAINT Satisfy::1_supplier_is_requirement The supplier shall be an element stereotyped by any subtype of «AbstractRequirement». OMG Systems Modeling Language (SysML) 1.6 Dependency, Dependency::supplier Requirement, Satisfy, AbstractRequirement::/satisfiedBy, AbstractRequirement requirements engineering, requirements analysis
INFO Satisfy::getSatisfies (in ref : NamedElement) : AbstractRequirement [0..*] OMG Systems Modeling Language (SysML) 1.6 Dependency, Dependency::supplier Requirement, Satisfy, AbstractRequirement, Satisfy::getSatisfies(in ref) requirements engineering, requirements analysis
INFO Schematic of a Keplerian refracting telescope. The arrow at (4) is a (notional) representation of the original image; the arrow at (5) is the inverted image at the focal plane; the arrow at (6) is the virtual image that forms in the viewer's visual sphere Wikipedia Keplerian refractor, telescope, refracting telescope, optical telescope
SEMANTIC Scientific notation consists of decimal notation followed by either the letter “e” or “E” and an exponent consisting of an optional sign character followed by one or more digits. ... Unified Modeling Language 2.5.1 value, notation, LiteralReal, Real, digit, scientific notation
INFO SendSignalAction::signal: The Signal whose instance is transmitted to the target. Unified Modeling Language 2.5.1 SendSignalAction::signal, SendSignalAction
INFO SendSignalAction::target: The InputPin that provides the target object to which the Signal instance is sent Unified Modeling Language 2.5.1 SendSignalAction::target, SendSignalAction, InputPin
INFO Sensors [DISPUTED] in office buildings for example, can adjust lights, blinds and temperature to balance optimal working environment with energy consumption, with the digital twin managing and adjusting in near real-time. ANZLIC 2019 - Principles for Spatially Enabled Digital Twins of the Built and Natural Environment in Australia