Fstachecki: /* Instance Specification⌘ */

2018-03-07T07:39:17Z

Instance Specification⌘

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[[Category:SysML]]
[[Category:private]]

==SysML Block Definition Diagram⌘==
===Block Definition Diagram⌘===
[[File:ClipCapIt-160722-114520.PNG]]
* The Block Definition Diagram in SysML defines features of blocks and relationships between blocks such as associations, generalizations, and dependencies.
* It captures the definition of blocks in terms of properties and operations, and relationships such as a system hierarchy or a system classification tree.
===Block⌘===
[[File:ClipCapIt-160726-104952.PNG]]
* Blocks are modular units of system description.
* Each block defines a collection of features to describe a system or other element of interest.
* These may include both structural and behavioral features, such as properties and operations
* SysML allows blocks to have multiple compartments appearing in any order, each optionally with name.
* In SysML all properties of a block have the visibility public.


====Block structure compartment⌘====
[[File:ClipCapIt-160722-125001.PNG]]
* A compartment with the label “structure” may appear as part of a block definition to show connectors and other internal structure elements for the block being defined.

===Relationships⌘===
====Generalization⌘====
[[File:ClipCapIt-160722-132259.PNG]]
* relationship between a more general classifier and a more specific classifier
* each instance of the specific classifier is also an indirect instance of the general classifier
* the specific classifier inherits the features of the more general classifier

====Association⌘====
[[File:ClipCapIt-160722-132107.PNG]]
* A unidirectional association has a default multiplicity of 1 on its target end.

====Part/Shared Association⌘====
[[File:ClipCapIt-160722-132036.PNG]]
* A part or shared association has a default multiplicity of [0..1] on the black or white diamond end.

====Containment⌘====
[[File:ClipCapIt-160722-132433.PNG]]
[[File:ClipCapIt-160725-091248.PNG]]

===ValueType⌘===
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* A ValueType defines types of values that may be used to express information about a system but has no identity.
* SysML defines ValueType as a stereotype of UML DataType.
* 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.
====Primitive Value Types⌘====
[[File:ClipCapIt-160722-125329.PNG]]
====Enumeration⌘====
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* An Enumeration is a Value Type whose values are enumerated in the model as literals.

====Unit and QuantityKind⌘====
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* A QuantityKind is a kind of quantity that may be stated by means of defined units.
* For example, the quantity kind of length may be measured by units of meters, kilometers, or feets.
=====Unit and QuantityKind example⌘=====
[[File:ClipCapIt-160722-162511.PNG]]

===Ports and Flows⌘===
* Ports and flows are useful to enable design of modular, reusable blocks with clearly defined ways of connecting and interacting with their context of use.
* Flow properties specify the kinds of items that might flow between a block and its environment, whether it is data, material, or energy.
* The kind of items that flow is specified by typing flow properties.
====Item Flow⌘====
[[File:ClipCapIt-160725-080454.PNG]]
* Item flows specify the things that flow between blocks and/or parts and across associations or connectors.
* Item flows specify what “does” flow between blocks and/or parts in a particular usage context, e.g. water or gasoline.

====Port⌘====
[[File:SysMLPort.png]]
* Ports are points at which external entities can connect to and interact with a block in different or more limited ways than connecting directly to the block itself.
* They are properties with a type that specifies features available to the external entities via connectors to the ports.
* SysML identifies two kinds of ports:
** '''proxy''' port - exposes features of the owning block or its internal parts
** '''full''' port - supports its own features, specifies separate elements of the system
* Proxy ports are always typed by interface blocks, a specialized kind of block that has no behaviors or internal parts.
* Ports that are not specified as proxy or full are simply called “ports.”

====Interface⌘====
[[File:ClipCapIt-160725-080406.PNG]]
* An Interface represents a declaration of a set of public Features and obligations that together constitute a coherent service.
* The set of Interfaces realized by a block are its '''Provided Interfaces''', which represent the services and obligations that instances of that block offer to their clients.
* '''Required Interfaces''' specify services that a block needs in order to perform its function and fulfill its own obligations to its clients.

===Instance Specification⌘===
[[File:ClipCapIt-160722-162038.PNG]]
* An Instance Specification is a model element that represents an instance in a modeled system.
* They are often used to model example configurations of instances.
* They may be partial or complete representations of the instances that they correspond to.
===Constraint Blocks⌘===
[[File:ClipCapIt-160722-163004.PNG]]
* Constraint blocks provide a mechanism for integrating engineering analysis such as performance and reliability models with other SysML models.
* Can be used to specify constraints that represent mathematical expressions such as {F=m*a} and {a=dv/dt}.
* Is a block that contains the statement of a constraint so it may be applied in a '''reusable''' way to constrain properties of other blocks.
* Can be defined on Block Definition Diagram or Package Diagram and used on Parametric Diagrams

SysML Block Definition Diagram - Revision history

Fstachecki: /* Instance Specification⌘ */