Overview of the main SysML stereotypes and additional MD SysML stereotypes. It includes just enough about each stereotype (and how it can be used in MD SysML) to get users started. Although this tutorial is still under development; it is already quite detailed and very useful.
SysML1.0:
A constraint block is a block that packages the statement of a constraint so it may be applied in a reusable way to constrain properties of other blocks. A constraint block typically defines one or more constraint parameters, which are bound to properties of other blocks in a surrounding context where the constraint is used.
SysML1.0:
A constraint property is a property of any block that is typed by a constraint block. It holds a localized usage of the constraint block. Binding connectors may be used to bind the parameters of this constraint block to other properties of the block that contains the usage.
There is already a detailed analysis of allocate here.
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There is already a detailed analysis of allocated here.
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SysML1.0:
A Binding Connector is a connector which specifies that the properties at both ends of the connector have equal values.
SysML1.0:
Value types may be used to type properties, operation parameters, or potentially other elements within SysML.
SysML 1.0:
SysML ValueType adds an ability to carry a unit of measure or dimension associated with the value.
SysML1.0:
SysML defines ValueType as a stereotype of UML DataType to establish a more neutral term for system values that may never be given a concrete data representation. For example, the SysML “Real” ValueType expresses the mathematical concept of a real number, but does not impose any restrictions on the precision or scale of a fixed or floating-point representation that expresses this concept. More specific value types can define the concrete data representations that a digital computer can process, such as conventional Float, Integer, or String types.
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SysML1.0:
A Block is a modular unit that describes the structure of a system or element. It may include both structural and behavioral features, such as properties and operations, that represent the state of the system and behavior that the system may exhibit. Some of these properties may hold parts of a system, which can also be described by blocks. A block may include a structure of connectors between its properties to indicate how its parts or other properties relate to one another.
SysML blocks provide a general-purpose capability to describe the architecture of a system. They provide the ability to represent a system hierarchy, in which a system at one level is composed of systems at a more basic level. They can describe not only the connectivity relationships between the systems at any level, but also quantitative values or other information about a system.
SysML does not restrict the kind of system or system element that may be described by a block...
Connectors owned by SysML blocks may be used to define relationships between parts or other properties of the same containing block..
SysML1.0:
Connectors can be typed by association classes that are stereotyped by Block (association blocks, see Section 8.3.2.7, “ParticipantProperty”). These connectors specify instances (links) of the association block that exist due to instantiation of the block owning or inheriting the connector. The value of a connector property on an instance of a block will be exactly those link objects that are instances of the association block typing the connector referred to by the connector property.
SysML1.0:
'.. a stereotype of Property used to apply a probability distribution to the values of the property. Specific distributions should be defined as subclasses of the DistributedProperty stereotype with the operands of the distributions represented by properties of those stereotype subclasses.'
SysML1.0:
.. extends a UML ConnectorEnd so that the connected property may be identified by a multi-level path of accessible properties from the block that owns the connector.
SysML1.0:
The Block stereotype extends Class, so it can be applied to any specialization of Class, including Association Classes. These are informally called “association blocks.” An association block can own properties and connectors, like any other block. Each instance of an association block can link together instances of the end classifiers of the association.
To refer to linked objects and values of an instance of an association block, it is necessary for the modeler to specify which (participant) properties of the association block identify the instances being linked at which end of the association The value of a participant property on an instance (link) of the association block is the value or object at the end of the link corresponding to this end of the association.
Participant properties can be the ends of connectors owned by an association block. The association block can be the type of multiple other connectors to reuse the same internal structure for all the connectors. The keyword «participant» before a property name indicates the property is stereotyped by ParticipantProperty. The types of participant properties can be elided if desired. They are always the same as the corresponding association end type.
SysML1.0:
Participant properties can be the ends of connectors owned by an association block.
SysML1.0:
The association block can be the type of multiple other connectors to reuse the same internal structure for all the connectors.
Every usage of AssociationBlock as a Connector typed by it is decomposed into finer connections between participants (and/or nested parts).
SysML1.0:
The PropertySpecificType stereotype is automatically applied to a classifier created by the notation for a property-specific type for a property belonging to a SysML Block or ValueType. It identifies these classifiers so that they may be managed along with the property that they type.
SysML1.0:
Property-specific type
Enclosing the type name of an internal property in square brackets specifies that the type is a local specialization of the referenced type, which may be overridden to specify additional values or other customizations that are unique to the property. Redefined or added features of the newly defined type may be shown in compartments for the property. If the property name appears on its own, with no colon or type name, or if no type name appears between the square brackets, the property-specific type is entirely provided by its own declarations, without specializing any existing type.
The PropertySpecificType was conceived to provide a value-carrier to enable deep assignment of values to an entire system within a given context, such as a configuration context. A PropertySpecificType is indicated by surrounding brackets when displaying a part within an IBD:
part:[Type]
It is essentially an "on-the-fly" re-definition ot a type used in a system, and can carry further PropertySpecificType redefinitions for its children, recursively to enable redefinition, and thus value definition, of an entire system (deeply).
This advanced feature is not yet fully supported by MD SysML; instead the MD SysML Plugin team is developing an alternative, more-flexible "value slice" strategy for assigning complete "value states" specific to a usage of an entire system within a given context.
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SysML1.0:
'A FlowPort is an interaction point through which input and/or output of items such as data, material, or energy may flow. This enables the owning block to declare which items it may exchange with its environment and the interaction points through which the exchange is made.'
SysML1.0:
'An ItemFlow describes the flow of items across a connector or an association. It may constrain the item exchange between blocks, block usages, or flow ports as specified by their flow properties. For example, a pump connected to a tank: the pump has an “out” flow property of type Liquid and the tank has an “in” FlowProperty of type Liquid. To signify that only water flows between the pump and the tank, we can specify an ItemFlow of type Water on the connector.'
SysML1.0: 9.3.2.6 ItemFlow:
'An ItemFlow .. may constrain the item exchange between blocks, block usages, or flow ports as specified by their flow properties. For example, a pump connected to a tank: the pump has an “out” flow property of type Liquid and the tank has an “in” FlowProperty of type Liquid. To signify that only water flows between the pump and the tank, we can specify an ItemFlow of type Water on the connector.'
SysML1.0: 9.3.2.6 ItemFlow:
'.. In addition, if there is an item property (corresponds to the conveyed classifier), then one can label the item flow with the item property. For example, a label of “liquid: Water” would imply that the item flow relays Water and this relay is associated with an item property “liquid” of the item flow, i.e., the “liquid” item property is set once Water is relayed.'
SysML1.0:
A property typed by a Block that does not have composite aggregation is classified as a reference property.
MD SysML distinguishes between a SharedProperty (with AggregationKind 'shared') and a true ReferenceProperty (with AggregationKind 'none'), which both extend AbstractReferenceProperty.
As recommended through SysML1.0 examples:
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Abstract base of the three kinds of properties (excluding ConstraintProperty) that can be typed by a Block: PartProperty, SharedProperty, ReferenceProperty
SysML1.0:
A Block that has composite aggregation is classifed as a part property. A property typed by a Block that does not have composite aggregation is classified as a reference property.
MD SysML distinguishes between a SharedProperty and a true ReferenceProperty which both extend AbstractReferenceProperty.
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Encapsulates the constraint parameter concept referred to in the 10.Constraints chapter of SysML1.0.
SysML1.0:
A constraint block typically defines one or more constraint parameters, which are bound to properties of other blocks in a surrounding context where the constraint is used.
SysML 1.0:
A constraint block is defined by a keyword of «constraint» applied to a block definition. The properties of this block define the parameters of the constraint
The MD SysML ConstraintParameter extends Port (which extends Property) to give convenient access to the small-box notation used for parameters in SysML Parametric Diagrams.
Encapsulates the part property concept introduced in SysML1.0 in 08.Blocks.
SysML1.0:
A property typed by a SysMLBlock that has composite aggregation is classifed as a part property.
Part properties may be shown in a block definition compartment with the label “parts" (in MD SysML use option Sort SysML style).
SysML1.0:
A property typed by a Block that does not have composite aggregation is classified as a reference property.
MD SysML distinguishes between a SharedProperty and a true ReferenceProperty which both extend AbstractReferenceProperty.
SysML1.0:
A property typed by a Block that does not have composite aggregation is classified as a reference property.
MD SysML distinguishes between a SharedProperty and a true ReferenceProperty which both extend AbstractReferenceProperty.
SysML1.0:
SysML also supports properties with shared aggregation, as shown by a white diamond symbol on an association. Like UML, SysML defines no specific semantics or constraints for properties with shared aggregation, but particular models or tools may interpret them in specific ways.
Encapsulates the value property concept, which appears informally throughout the SysML1.0 specification, especially in Chapters 08.Blocks and 10.Constraints.
SysML1.0:
A property typed by a UML DataType or SysML ValueType is classified as a value property.
Value properties may be shown in a block definition compartment with the label “values” (in MD SysML use option Sort SysML style).