Dr Darren says: 'You can't obtain the optimum benefit of graphical engineering with SysML without becoming mindful of the cognitive and artistic aspects of graphical modelling. The "Zen of SysML" matters!' Just like an elegant electronics device design.
The Webel recipe for pragramatic SE with SysML omits many of the concerns addressed by fully-fledged systems engineering frameworks. Many of these can be partially addressed by using custom Stereotypes for extraction using query view tables.
Webel: SysML: SE: The custom stereotype keyword «design» covers elements involved with BOTH design and/or implementation aspects in the 'solution' zone. (In more comprehensive SE methodologies design and implementation are often treated separately.)
Webel: SysML: SE: Naming convention: '0' used for a Package/Model name indicates a zone dedicated to a formal systems engineering breakdown (functional analysis, blackbox, whitebox, logical vs design or implementation etc.)
SysML tools can ALSO be used for many graphical Model-Based Engineering tasks that benefit from Single Source Of Truth - and even without any formal System Engineering methodology (which is NOT to say that formal System Engineering is not also useful).
Webel: Dr Darren says: "Many aspects of older Document-Intensive Systems Engineering methodologies and the reporting obligations they impose on their users were intended to address problems that simply DO NOT EXIST ANYMORE with modern MBSE with SysML!"
Webel: SysML: "Really long human friendly element names with spaces make my diagrams easier to read". Dr Darren says "No they don't! Prefer code-like naming (or anonymous for typed elements) wherever possible. Use custom tagged values for other names!"
Webel: SysML: Heard of "follow the money"? In MBSE we "follow the flows"! Identify requests, data packets, message, signals early on and use ItemFlow as often as you can wherever you can! Adopt a signal processing mindset throughout (systems thinking).
Webel: SysML/MBSE: Dr Darren's Open Letter on why you may initially need the Model-Based (MB) and Single Source Of Truth aspects of MBSE more than the formal Systems Engineering (SE) aspect (or even initially no formal SE process at all) to benefit most!
Webel: SysMLv1: Dr Darren for LinkedIn: On "Trusting The Type" and avoiding unnecessary verbose repetitive Property names ... unless you really, really need them and really do have reasons to use them, and then only use concise role indicators anyway!
Webel: SysML/UML: Some example diagrams show extremely fine-grained and trivial examples purely for educational and capability demonstration purposes (not as practical recommendations for real-world projects). You can sometimes just use code in SysML.
Webel: SysML: MagicDraw/Cameo: Strongly recommend that you set the Perspective to 'Full Featured' and 'Expert' at the very beginning at the start of every new project
Webel Parsing Analysis for SysML: Track and display alternative names, human friendly names, organisation-specific names, and identifiers using tagged values for a custom stereotype «pa:term» (adapt or extend as required).
Using Model-Based Systems Engineering with ANY version of Systems Modeling Language (SysML) is better than just doing drawings in a graphics tool or presentation tool
You DO NOT have to wait for SysMLv2 to do Model-Based Systems Engineering with SysML! You can do MOST of what you need to do with SysMLv1.6/1.7 and you WILL be able to migrate models to SysMLv2 once tool support matures. Start your SysML models NOW!
Webel: SysMLv2: PROPOSAL: New Causality Graph Diagram for coordinating MetaEvents across an entire model
Webel Parsing Analysis: A Parsing Analysis Container MAY collect any other Element type as a member EXCEPT for another Parsing Analysis Container
Webel Parsing Analysis: The symbol for a Parsing Analysis Container MUST be able to indicate the unique domain source document from which its analysed text extract was quoted.
Webel Parsing Analysis: The symbol for a Parsing Analysis Container MUST be able to OPTIONALLY display a list of names of elicited model elements (a.k.a. members)
Webel Parsing Analysis: It SHOULD be possible to relate one Parsing Analysis Container to another and stereotype that relationship as an RDF/OWL-like semantic triple
Webel Parsing Analysis: It MUST be possible to collect elicited members of a Parsing Analysis Container graphically in diagrams using relationship-like path drawing (not just via a specification dialog or other indirect modelling means)
Webel Parsing Analysis: The symbol for the relationship between a Parsing Analysis Container and elicited model elements SHOULD be a dashed line (like the anchor/handle line used with a UML Comment)
Webel Parsing Analysis: The symbol for a Parsing Analysis Container MUST be text-friendly and evocative of quoting a domain source text extract
Webel Parsing Analysis: The symbol of a Parsing Analysis Container MUST be usable on every possible diagram type
SysML: The placement of usages of Blocks, their Ports, and Connectors in an Internal Block Diagrams DOES NOT necessarily represent physical geometry!
In the Webel terminology for a basic control loop there is an 'aim' value (controlled via an actuator) and a 'got' value (a value read from a sensor). The 'got' value is NOT necessarily exactly the same as the actual physical value.
Webel: SysML: DO NOT sacrifice modelling naming conventions for the mere sake of carrying organisation-specific names! Instead use tagged values of custom stereotypes as metadata to carry alternative names in parallel with systematic model element names.
Webel: In some SysML trails ValueType names with Unit indicator suffixes have been used for dimensional analysis and illustrative purposes. This practice is NOT otherwise recommended here. Instead just use consistent custom ValueTypes across your system!
Sample problems and example diagrams in graphical language specifications are NOT necessarily indications of how one should model on a real-world project! They often just serve to demonstrate a particular aspect of the specified language.
Webel: UML/SysML: Navigation: ALWAYS offer a way out of a diagram (usually up a hierarchy, but possibly across) using a navigable symbol (linked to a diagram) and/or a diagram symbol. Avoid "cul-de-sacs"! [But beware of shared package cross-dependencies]
Webel vs SysPhS-1.1: Diagramming style: DO NOT recommend overlapping Connectors with "phantom" fork (or junction) as shown in in 'Figure 48: Internal structure of the signal processor'
UML/SysML: If you have a Boolean "state flag" attribute corresponding to a State you MUST set it on an 'entry' of the State, not on the 'effect' of a Transition into the State (otherwise with multiple incoming Transitions it could be WET and breaks SSoT).
Webel Twin Pattern: Once a PotentialPhysicalAsset has been integrated with a real, existing (has mass) ActualPhysicalAsset under twinning control, its job is done forever (although it may be kept as an historical tracking record).
Webel Twin Pattern: A DigitalTwin (even a "process twin" or "finance twin"), always, without exception, BY DEFINITION HERE either directly or indirectly involves at least one existing or anticipated PhysicalEntity (even if only via another DigitalTwin)!
Webel Twin Pattern: A DigitalEntity (a.k.a. «digital» @Entity) used as a digital variant must not be directly bound to a «physical» PhysicalEntity (may not directly actuate/sense/affect)
Webel Twin Pattern: A DigitalTwin may use one or more variantEntity:@Entity[0..*] to explore the impact of changes (optimisation studies, trade off studies) and then use them to drive the PhysicalEntity into a desired state (via its ControlSystem).
Webel Twin Pattern: The primary aim of the digitalEntity:@Entity of a DigitalTwin is to replicate its physical:PhysicalEntity as closely as possible (not to explore variants).
Webel Twin Pattern: A «digital» DigitalEntity (a.k.a. @Entity) is NOT a representation! It is a digital encapsulation (it can only be perceived at the level of "bits and bytes"). It HAS many representations (such as views)!
WARNING: In natural language casual conversation one often hears people speaking of a digital twin "replicating" or "twinning" a physical entity. If you do it that way literally, you will NOT have anything to manage the control system loop!
Webel Twin Pattern: A PotentialPhysicalAsset is «digital», not «physical». It is used to acquire (an existing) or create (build, manifest, make) an «physical» ActualPhysicalAsset, which is a special case of «physical» PhysicalEntity.
Webel Twin Pattern: A DigitalTwin manages a control loop including a PhysicalEntity and a DigitalEntity (a.k.a. @Entity) that «replicates» it. It typically includes at least one Sensor and at least one Actuator.
Webel Twin Pattern: It is a DigitalEntity (a.k.a. @Entity) - not the DigitalTwin that owns it - that directly «replicates» geometrical, spatial, and material aspects (only) of a single PhysicalEntity.
Webel Twin Pattern: A «digital» DigitalEntity (a.k.a. @Entity) encapsulates strictly geometrical, spatial, and material aspects of a «physical» PhysicalEntity only. BY DEFINITION of this pattern it DOES NOT encapsulate processes!
Webel: SysML-1.7/SysMLv2: WISHLIST: Constraint: A BindingConnector used for pure proxying MUST NOT be typed by an AssociationBlock by definition, because the associated information can be mis-appropriated to undermine the proxy equality!
Webel: SysMLv2: WISHLIST: Manage "cascading" Satisfy claim vs Block inheritance hierarchy with redefined properties
Webel: SysMLv2: WISHLIST: Suggest declare an custom Stereotype as 'cascading' then behave likes constraint rules for Block
WISHLIST: Webel has suggested that future SysML should support the display of Classifier-level :features in compartments on a rectangular itemProperty symbol on an ItemFlow on a Connector in an IBD.
ALL Model-Based Engineering: Just because you can't see a Feature or some other aspect of a SysML (or UML) Element in a tool on a symbol does NOT mean it does not exist in the underlying model (repository)! The model is not just what is DISPLAYED!
Nobody (informed) said that SysML (or even UML) modelling and MBSE is only about graphical modelling, notations, and diagrams! Information can be extracted in many different ways and presented in many different formats from the underlying model!
Dependency/Usage relationships in some referenced UML/SysML diagrams on this site are for educational illustration only, they are NOT part of the actual model.
SysML: MagicDraw/Cameo: Diagram Style: Recommend DO NOT use shadows or gradient fill adornments on diagrams! [TIP OFTEN IGNORED]
Webel: SysML symbol colour styles: Recommend use black symbol borders and no symbol fill (or white symbol fill) EXCEPT for special highlighting. Recommend DO NOT use the default VENDOR-SPECIFIC line and fill colours for symbols! [TIP IS MOSTLY IGNORED]
