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
SEMANTIC A StringExpression is an Expression that specifies a String value that is derived by concatenating a list of substrings. Unified Modeling Language 2.5.1 Expression, StringExpression, String, value
NOTATION A subject for a set of UseCases (sometimes called a system boundary) may be shown as a rectangle with its name in the top-left corner, with the UseCase ellipses visually located inside this rectangle. Unified Modeling Language 2.5.1 UseCase, UseCase Diagram, UseCase::subject
INFO A subject of a UseCase could be a system or any other element that may have behavior, such as a Component or Class. Unified Modeling Language 2.5.1 UseCase, Behavior, BehavioredClassifier, Class, Component, UseCase::subject
SEMANTIC A submachine State implies a macro-like insertion of the specification of the corresponding submachine StateMachine. It is, therefore, semantically equivalent to a composite State. Unified Modeling Language 2.5.1 State, StateMachine, submachine, composite State
SEMANTIC A submachine StateMachine can be entered via its default (initial) Pseudostate or via any of its entry points (i.e., it may imply entering a non-orthogonal or an orthogonal composite State with Regions). Entering via the initial Pseudostate ... Unified Modeling Language 2.5.1 State, StateMachine, submachine, Pseudostate, Region, PseudostateKind::initial, State::/isComposite, State::/isSubmachineState, composite State, entry point
RULE a submachine Statemachine can be exited as a result of: reaching its FinalState; triggering of a group Transition originating from a submachine State, or; via any of its exit points. Unified Modeling Language 2.5.1 State, StateMachine, submachine, FinalState, State::exit, group Transition, exit point
NOTATION A synchronous Message (messageSort equals synchCall) has a filled arrow head. OMG Systems Modeling Language (SysML) 1.6 Message, MessageEnd, Message::messageSort, MessageSort, MessageSort::synchCall
INFO A SysML ValueType may define its own properties and/or operations, just as for a UML DataType. OMG Systems Modeling Language (SysML) 1.6 DataType, Property, Operation ValueType, Unit, QuantityKind
INFO A telescope is an optical instrument using lenses, curved mirrors [DISPUTED], or a combination of both to observe distant objects ... Wikipedia telescope, optical telescope, astronomy
INFO A telescope's ability to resolve small detail is directly related to the diameter (or aperture) of its objective (the primary lens or mirror that collects and focuses the light), and its light gathering power is related to the area of the objective. Wikipedia optical telescope, telescope, light, image, lens, mirror, inverting telescope
INFO A test case is a method for verifying a requirement is satisfied. OMG Systems Modeling Language (SysML) 1.6 TestCase, Requirement, Verify, Satisfy, VerdictKind::pass, VerdictKind::fail, VerdictKind::inconclusive, VerdictKind::error requirements engineering, test engineering
INFO A thermodynamic system does not contain heat. Nevertheless, the term is also often used to refer to the thermal energy contained in a system as a component of its internal energy and that is reflected in the temperature of the system. Wikipedia heat, thermodynamics, energy, energy transfer
INFO A TimeEvent is an Event that occurs at a specific point in time. Unified Modeling Language 2.5.1 Event, TimeEvent, TimeEvent::isRelative, TimeEvent::when time
CONSTRAINT A token may traverse only one of the outgoing edges. Unified Modeling Language 2.5.1 Activity, ObjectNode, token, object token, ActivityEdge
EXAMPLE, INFO A traction index is calculated every 10 ms, which is the slower of the two signal rates. The accelerometer signals come in continuously, which means the input to Calculate Traction does not buffer values. OMG Systems Modeling Language (SysML) 1.6 SysML specification figure, Rate, Rate::rate, Continuous, «continuous»
INFO A trade study or trade-off study, also known as a figure of merit analysis or a factor of merit analysis, is the activity of a multidisciplinary team to identify the most balanced technical solutions among a set of proposed viable solutions (FAA 2006). Wikipedia trade study, trade-off study
INFO A Transition is a single directed arc originating from a single source Vertex and terminating on a single target Vertex (the source and target may be the same Vertex), which specifies a valid fragment of a StateMachine Behavior. Unified Modeling Language 2.5.1 State, StateMachine, Transition
INFO A Transition may own a set of Triggers, each of which specifies an Event whose occurrence, when dispatched, may trigger traversal of the Transition. A Transition trigger is said to be enabled if the dispatched Event occurrence matches its Event type. Unified Modeling Language 2.5.1 State, StateMachine, Transition, Trigger, Transition::trigger, Event, Event occurrence, Trigger::event
INFO A Transition represents an arc between exactly one source Vertex and exactly one Target vertex (the source and targets may be the same Vertex). It may form part of a compound transition, which takes the StateMachine from one steady State configuration... Unified Modeling Language 2.5.1 State, StateMachine, Transition, Vertex, compound transition, Transition::source, Transition::target
INFO A trigger for an AnyReceiveEvent is triggered by the receipt of any message that is not explicitly handled by any related trigger. Unified Modeling Language 2.5.1 Event, MessageEvent, AnyReceiveEvent, Trigger, Trigger::event, Message
INFO A Trigger may be qualified by the Port on which the Event occurred. Unified Modeling Language 2.5.1 Event, Trigger, Trigger::event, Port, Trigger::port
INFO A Trigger specifies a specific point at which an Event occurrence may trigger an effect in a Behavior. Unified Modeling Language 2.5.1 Event, Behavior, Trigger, Event occurrence, Trigger::event
INFO A typical example is the allocation of activities to blocks (e.g., functions to components) OMG Systems Modeling Language (SysML) 1.6 Allocate, behavior allocation functional allocation
INFO A Unit is a quantity in terms of which the magnitudes of other quantities that have the same quantity kind can be stated. OMG Systems Modeling Language (SysML) 1.6 QuantityKind, Unit, Unit::quantityKind, ValueType::quantityKind, Unit::definitionURI, QuantityKind::definitionURI scientific unit system, VIM3
INFO A unit may also specify less stable or precise ways to express some value, such as a cost expressed in some currency, or a severity rating measured by a numerical scale. OMG Systems Modeling Language (SysML) 1.6 QuantityKind, Unit, Unit::quantityKind, ValueType::quantityKind, Unit::definitionURI, QuantityKind::definitionURI scientific unit system, VIM3
INFO A unit often relies on precise and reproducible ways to measure the unit. For example, a unit of length such as meter may be specified as a multiple of a particular wavelength of light. OMG Systems Modeling Language (SysML) 1.6 QuantityKind, Unit, Unit::quantityKind, ValueType::quantityKind, Unit::definitionURI, QuantityKind::definitionURI scientific unit system, VIM3
INFO A Usage is a Dependency in which the client Element requires the supplier Element (or set of Elements) for its full implementation or operation. Unified Modeling Language 2.5.1 Usage, Dependency, Dependency::client, Dependency::supplier, DirectedRelationship, NamedElement
INFO A UseCase can include possible variations of its basic behavior, including exceptional behavior and error handling. Unified Modeling Language 2.5.1 UseCase, Behavior, BehavioredClassifier error handling
INFO A UseCase is a kind of BehavioredClassifier that represents a declaration of a set of offered Behaviors. Each UseCase specifies some behavior that a subject can perform in collaboration with one or more Actors. Unified Modeling Language 2.5.1 UseCase, UseCase::subject, Classifier, Behavior, Actor, BehavioredClassifier
NOTATION A UseCase is shown as an ellipse, either containing the name of the UseCase or with the name of the UseCase placed below the ellipse. An optional stereotype keyword may be placed above the name. Unified Modeling Language 2.5.1 UseCase, UseCase Diagram, «keyword», Stereotype
INFO A UseCase may apply to any number of subjects. When a UseCase applies to a subject, it specifies a set of behaviors performed by that subject, which yields an observable result that is of value for Actors or other stakeholders of the subject. Unified Modeling Language 2.5.1 UseCase, UseCase::subject, Classifier, Behavior, Actor
INFO A UseCase may be owned either by a Package or by a Classifier. Although the owning Classifier typically represents a subject to which the owned UseCases apply, this is not necessarily the case ... Unified Modeling Language 2.5.1 UseCase, UseCase::subject, Behavior, BehavioredClassifier, Package, Classifier
INFO A UseCase specifies a set of actions performed by its subjects, which yields an observable result that is of value for one or more Actors or other stakeholders of each subject. Unified Modeling Language 2.5.1 UseCase
SEMANTIC A value of unlimited (“*”) for the insertion point means to insert the new value at the end of the sequence. Unified Modeling Language 2.5.1 StructuralFeature, AddStructuralFeatureValueAction, StructuralFeatureAction, AddStructuralFeatureValueAction::insertAt, UnlimitedNatural, multiplicity, *
INFO A ValuePin provides a value by evaluating a ValueSpecification ... When the Action is enabled by other means, the ValueSpecifiation of the ValuePin is evaluated, and the result is provided as an input to the Action when it begins execution. Unified Modeling Language 2.5.1 Activity, Activity Diagram, Action, Pin, InputPin, ValuePin, ValueSpecification, ValuePin::value
INFO A ValueSpecification is the specification of a (possibly empty) set of values. A ValueSpecification is a ParameterableElement that may be exposed as a formal TemplateParameter and provided as the actual parameter in the binding of a template. Unified Modeling Language 2.5.1 Property, Property::defaultValue, ValueSpecification, ParameterableElement UML, Unified Modeling Language
INFO A ValueType defines types of values that may be used to express information about a system, but cannot be identified as the target of any reference. OMG Systems Modeling Language (SysML) 1.6 DataType ValueType
INFO A Verify relationship is a dependency between a requirement and a test case or other model element that can determine whether a system fulfills the requirement. As with other dependencies, the arrow direction points from the (client) element to the (suppl OMG Systems Modeling Language (SysML) 1.6 Dependency, Dependency::client, Dependency::supplier Verify, Requirement
INFO A Vertex is an abstraction of a node in a StateMachine graph. It can be the source or destination of any number of Transitions. Unified Modeling Language 2.5.1 Vertex, StateMachine, Transition, DirectedRelationship::/source, DirectedRelationship::/target
INFO A Viewpoint is a specification of the conventions and rules for constructing and using a view for the purpose of addressing a set of stakeholder concerns. They specify the elements expected to be represented in the view... OMG Systems Modeling Language (SysML) 1.6 Viewpoint, Stakeholder, Stakeholder::/concern, Viewpoint::/concern, View
INFO a virtual image is found by tracing real rays that emerge from an optical device (lens, mirror, or some combination) backward to perceived or apparent origins of ray divergences. Wikipedia optics, image, light ray, focus point, real image, virtual image
INFO A.2.2 System being modeled: The electrical circuit has six components: ground, electrical source, inductor, capacitor, and two resistors, see Figure 37. SysPhS-1.1 SysPhS
INFO A.3.2 System being modeled The signal processor and its testbed have a wave generator, an amplifier, high-pass and low-pass frequency filters, a mixer, and a signal sink, see Figure 46. SysPhS-1.1 SysPhS, signal processing, high-pass filter, low-pass filter, sine wave generator
INFO A.4.1 Introduction: This subannex gives a model of a simple hydraulic system as an example of physical interaction (fluid flow). It does not include any signal flows SysPhS-1.1 SysPhS, hydraulics, fluid flow, physical interaction
INFO A.4.2 System being modeled: The hydraulic system has three components: two fluid reservoir tanks and a pipe for connecting these tanks, see Figure 58. SysPhS-1.1 SysPhS, hydraulics
INFO A.5 Humidifier: A.5.1 Introduction: This subannex gives a model of a room humidifier as an example of signal flows and state machines. SysPhS-1.1 SysPhS, humidifier, HVAC&R
INFO A.5.2 System being modeled: The total humidifier system has two main components: the humidified room and the humidifier, see Figure 64. SysPhS-1.1 SysPhS, humidifier, HVAC&R
INFO A.5.3 Internal structure: Figure 65 through Figure 71 show the internal structure of the total humidifier system and its components through seven nested internal block diagrams. SysPhS-1.1 SysPhS, humidifier, HVAC&R
INFO AbstractRequirement::/master : AbstractRequirement [0..*] This is a derived property that lists the master requirement for this slave requirement. The master attribute is derived from the supplier of the Copy dependency ... OMG Systems Modeling Language (SysML) 1.6 Dependency::supplier, Dependency::client AbstractRequirement, Requirement, Copy, AbstractRequirement::/master, AbstractRequirement::text requirements engineering
INFO AbstractRequirement::/tracedTo : NamedElement [0..*] Derived from all elements that are the client of a «trace» relationship for which this requirement is a supplier. (derived) [ERROR] OMG Systems Modeling Language (SysML) 1.6 «trace» Trace, AbstractRequirement::/tracedTo
SEMANTIC AcceptEventAction is an Action with Triggers for one or more Events. When an AcceptEventAction is executed, it waits for an Event occurrence to be dispatched from the event pool of the context object for its execution that matches one of its Triggers. Unified Modeling Language 2.5.1 Action, AcceptEventAction, Trigger, Event, event pool
INFO According to certain theories, neutrinos may be their own antiparticle. It is not currently known whether this is the case. Wikipedia
INFO According to the spin-statistics theorem in any reasonable relativistic quantum field theory, particles with integer spin are bosons, while particles with half-integer spin are fermions. Wikipedia
INFO Action::/input : InputPin [0..*] ... The ordered set of InputPins representing the inputs to the Action. Unified Modeling Language 2.5.1 Action, Action::/input, InputPin
INFO Action::/output : OutputPin [0..*] ... The ordered set of OutputPins representing outputs from the Action. Unified Modeling Language 2.5.1 Action, Action::/output, OutputPin
INFO Activities as blocks can have associations between each other, including composition associations. Composition means that destroying an instance at the whole end destroys instances at the part end. OMG Systems Modeling Language (SysML) 1.6 Activity, Association, AggregationKind::composite Block
INFO, NOTATION Activities in block definition diagrams appear as regular blocks, except the «activity» keyword may be used to indicate the Block stereotype is applied to an activity, as shown in Figure 11-1. See example in 11.4, Usage Examples. OMG Systems Modeling Language (SysML) 1.6 Activity «activity», SysML Block Definition Diagram, Block
INFO, NOTATION Activities in block definition diagrams can also appear with the same notation as CallBehaviorAction, except the rake notation can be omitted, if desired. Also see use of activities in block definition diagrams that include ObjectNodes. OMG Systems Modeling Language (SysML) 1.6 CallBehaviorAction, ObjectNode, Activity SysML Block Definition Diagram functional allocation, functional decomposition
INFO Activity diagrams have also been modified via the activity extensions. OMG Systems Modeling Language (SysML) 1.6 Diagram, Activity Diagram SysML Activity Diagram
INFO Actors represent classifier roles that are external to the system that may correspond to users, systems, and or other environmental entities. OMG Systems Modeling Language (SysML) 1.7beta1 Actor, UseCase::subject, UseCase
RULE Adding a value to an ordered StructuralFeature requires an insertion point for the new value given in the insertAt InputPin, which is required for ordered StructuralFeatures when isReplaceAll is false and omitted for unordered StructuralFeatures. Unified Modeling Language 2.5.1 StructuralFeature, AddStructuralFeatureValueAction, StructuralFeatureAction, AddStructuralFeatureValueAction::insertAt, InputPin
INFO After each execution of the bodyPart, the test section is executed again, for the next iteration of the loop. Unified Modeling Language 2.5.1 Activity, Activity Diagram, LoopNode, LoopNode::test, LoopNode::bodyPart, LoopNode:decider
INFO After the completion of each execution of the bodyPart of the LoopNode, any remaining tokens on the loopVariable OutputPins are destroyed and tokens on the bodyOutput OutputPins are copied to the corresponding loopVariable OutputPins so that they are ... Unified Modeling Language 2.5.1 Activity, Activity Diagram, LoopNode, LoopNode::loopVariable, OutputPin, LoopNode::bodyOutput
INFO All concrete kinds of ExecutableNodes are Actions ... Unified Modeling Language 2.5.1 Behavior, Activity, Activity Diagram, ExecutableNode, ActivityNode, execution, Action
NOTATION All features shown within these compartments shall match those of the block or value type that types the property. OMG Systems Modeling Language (SysML) 1.6 compartment property compartment, SysML Internal Block Diagram, IBD :features compartments, :values compartment, :parts compartment, :properties compartment, :references compartment, :flow properties compartment, :operations compartment
INFO All mesons are unstable, with the longest-lived lasting for only a few hundredths of a microsecond. Wikipedia
INFO, NOTATION All ports and nested ports (i.e., proxy, full, and ports with no stereotype applied), and their type definitions (e.g., interface blocks, blocks) can include compartments with textual and graphical representations to display their features ... OMG Systems Modeling Language (SysML) 1.6 Port, compartment, Property, Feature nested Port, block compartment, ProxyPort, FullPort, Block, InterfaceBlock
INFO All properties of a constraint block are constraint parameters, with the exception of constraint properties that hold internally nested usages of constraint blocks. OMG Systems Modeling Language (SysML) 1.6 ConstraintBlock, constraint parameter, MD:ConstraintParameter, BindingConnector, constraint property
INFO All properties that appear, other than the constraints themselves, shall either be bound directly to a constraint parameter, or contain a property that is bound to one (through any number of levels of containment). OMG Systems Modeling Language (SysML) 1.6 Property SysML Parametric Diagram, constraint parameter, constraint property, MD:ConstraintParameter, BindingConnector
INFO All refracting telescopes use the same principles. The combination of an objective lens and some type of eyepiece is used to gather more light than the human eye is able to collect on its own, focus it, and present the viewer with a brighter, clearer, ... Wikipedia
CONSTRAINT All tokens offered on the incoming edges of a MergeNode are offered to the outgoing edge. There is no synchronization of flows or joining of tokens. Unified Modeling Language 2.5.1 Activity, Activity Diagram, ControlNode, MergeNode, ActivityNode::outgoing, ActivityNode::incoming, token, control token, object token
INFO Allocate is a dependency based on UML::Abstraction. It is a mechanism for associating elements of different types, or in different hierarchies, at an abstract level. Allocate is used for assessing user model consistency and directing future design ... OMG Systems Modeling Language (SysML) 1.6 Allocate, allocation
INFO Allocate is a stereotype of a UML4SysML::Abstraction that is permissible between any two NamedElements. It is depicted as a dependency with the "allocate" keyword attached to it. OMG Systems Modeling Language (SysML) 1.6 «keyword», Abstraction, NamedElement Allocate, allocation, «allocate»
INFO Allocate is directional in that one NamedElement is the "from" end (no arrow), and one NamedElement is the "to" end (the end with the arrow). OMG Systems Modeling Language (SysML) 1.6 «keyword», Abstraction, NamedElement Allocate, allocation, «allocate»
INFO AllocateActivityPartition is used to depict an «allocate» relationship on an Activity diagram. The AllocateActivityPartition is a standard UML::ActivityPartition, with modified constraints... OMG Systems Modeling Language (SysML) 1.6 ActivityPartition AllocateActivityPartition
CONSTRAINT AllocateActivityPartition::1_actions_on_client_ends An Action appearing in an "AllocateActivityPartition" shall be the /client (from) end of an "allocate" dependency. The element that represents the "AllocateActivityPartition" shall be the /supplier ... OMG Systems Modeling Language (SysML) 1.6 Dependency::client, Dependency::supplier AllocateActivityPartition, Allocate
INFO AllocateActivityPartition::2_not_uml_semantics ... Classifiers or Properties represented by an «AllocateActivityPartition» do not have any direct responsibility for invoking behavior depicted within the partition boundaries. ... OMG Systems Modeling Language (SysML) 1.6 ActivityPartition AllocateActivityPartition, behavior allocation functional allocation
INFO AllocateActivityPartition::2_not_uml_semantics The «AllocateActivityPartition» shall maintain the constraints, but not the semantics, of the UML::ActivityPartition. OMG Systems Modeling Language (SysML) 1.6 ActivityPartition AllocateActivityPartition, behavior allocation functional allocation
INFO Allocation is the term used by systems engineers to denote the organized cross-association (mapping) of elements within the various structures or hierarchies of a user model. OMG Systems Modeling Language (SysML) 1.6 Allocate
EXAMPLE, INFO Allocation of ControlFlow is not shown as an example, but it is not prohibited in SysML. OMG Systems Modeling Language (SysML) 1.6 ControlFlow SysML specification figure, Allocate
EXAMPLE, INFO Also note that this state machine refines the requirement “PowerSourceManagment,” which will be elaborated in the requirements sub clause of this sample problem. OMG Systems Modeling Language (SysML) 1.6 State, StateMachine, StateMachine Diagram, Requirement HSUV sample problem black box, Object Constraint Language
EXAMPLE, INFO Also, a background such as a map can be included to provide additional context. OMG Systems Modeling Language (SysML) 1.6 image context diagram, SysML Internal Block Diagram
INFO Also, the fluid flow in the tank, fluidFlow, is related to the change in the fluid height level fluidHeight over time and the cross-sectional surface area of the tank, surfaceArea. SysPhS-1.1 Constraint constraint parameter, ConstraintBlock SysPhS, pressure, hydraulics, fluid flow
CONSTRAINT Alternatively, the joinSpec may consist of an Expression with the name of a single Boolean operator and no operands specified. In this case, the value of the joinSpec shall be given by applying the given operator to Boolean values indicating ... Unified Modeling Language 2.5.1 Activity, Activity Diagram, ControlNode, JoinNode, ActivityNode::incoming, ActivityEdge, JoinNode::joinSpec, Boolean, Expression
INFO Although protons were originally considered fundamental or elementary particles, in the modern Standard Model of particle physics, protons are classified as hadrons, like neutrons, the other nucleon. Wikipedia
INFO Although SysML indirectly imports the UML 2 PrimitiveTypes library ... due to the transitivity of package import, SysML provides a PrimitiveValueTypes model library that systems engineers can extend via SysML’s ValueType stereotype. OMG Systems Modeling Language (SysML) 1.6 ModelLibrary ValueType, PrimitiveValueType
INFO Although the focus is conceptually a point, physically the focus has a spatial extent, called the blur circle. This non-ideal focusing may be caused by aberrations of the imaging optics. Wikipedia optics, image, light ray, focus point, focus, image point, blur circle
INFO An AbstractRequirement establishes the attributes and relationships essential to any potential kind of requirement. Any intended requirement kind should subclass AbstractRequirement. OMG Systems Modeling Language (SysML) 1.6 AbstractRequirement, Requirement
SEMANTIC An AcceptEventAction is a wait point ... except only the AcceptEventAction waits, rather than the whole Activity (Activities can have other Actions executing while AcceptEventActions are waiting). Unified Modeling Language 2.5.1 Activity, Action, AcceptEventAction, wait point
An AcceptEventAction with a trigger for a SignalEvent is informally called an accept signal action. Unified Modeling Language 2.5.1 AcceptEventAction, accept signal action, AcceptEventAction::isUnmarshall, OutputPin, Trigger, SignalEvent, Signal
INFO An Action cannot start execution if one of its InputPins has fewer values than the lower multiplicity of that InputPin. Unified Modeling Language 2.5.1 Activity, Activity Diagram, Action, Pin, InputPin, Action::/input, MultiplicityElement::/lower, execution
INFO An Action continues executing until it has completed. The detailed semantics of the execution of an Action and the definition of its completion depend on the particular kind of Action being executed. Unified Modeling Language 2.5.1 Activity, Activity Diagram, Action, execution, completion
INFO An Action may accept inputs and produce outputs, as specified by InputPins and OutputPins of the Action, respectively. Each Pin on an Action specifies the type and multiplicity for a specific input or output of that Action. Unified Modeling Language 2.5.1 Activity, Activity Diagram, Action, Pin, InputPin, OutputPin, Action::/input, Action::/output, multiplicity, Type
INFO An Action may not put more values into an output in a single execution than the [upper] multiplicity of that OutputPin. Unified Modeling Language 2.5.1 Activity, Activity Diagram, Action, Pin, OutputPin, Action::/output, execution, MultiplicityElement::/upper
RULE An Activity may have more than one InitialNode. Unified Modeling Language 2.5.1 Activity, InitialNode, ControlNode
INFO An Activity shall have one ActivityParameterNode corresponding to each in, out, or return Parameter and two ActivityParameterNodes for each inout Parameter. Unified Modeling Language 2.5.1 Activity, Behavior, Parameter, ActivityParameterNode, ActivityEdge, ParameterDirectionKind::in, ParameterDirectionKind::out, ParameterDirectionKind::inout, ParameterDirectionKind::return
INFO An ActivityFinalNode is a FinalNode that stops all flows in an Activity (or StructuredActivityNode, see sub clause 16.11). A token reaching an ActivityFinalNode owned by an Activity terminates the execution of that Activity. Unified Modeling Language 2.5.1 Activity, Activity Diagram, ControlNode, FinalNode, termination, token, ActivityFinalNode
INFO An ActivityParameterNode shall have either all incoming or all outgoing ActivityEdges. An ActivityParameterNode with outgoing edges is an input ActivityParameterNode, while an ActivityParameterNode with incoming edges is an output ActivityParameterNode. Unified Modeling Language 2.5.1 Activity, Behavior, Parameter, ActivityParameterNode, ActivityEdge
INFO An Actor specifies a role played by a user or any other system that interacts with the subject. Unified Modeling Language 2.5.1 Actor, UseCase::subject, UseCase
INFO An actuator is a device that is responsible for moving or controlling a mechanism or system. It is controlled by a signal from a control system or manual control. Wikipedia sensor, control system