Enterprise Architecture Modelling

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title

Enterprise Architecture Modelling

author

Bernard Szlachta (bs@NobleProg.co.uk)

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Modelling Activities。

Process can contain following steps:

• Design
  • Common language spanning all domain
  • Best practices
  • Revision control
• Communication
  • Shared model
  • Publishing
  • Comments and discussion (wiki, forum, etc...)
• Realisation
  • Keep in sync
  • Link between software and design (url, mda, etc..)
• Change
  • Tools for assessing the impact of change

Views Alignment。

• Solved by mapping
• Can be extremely hard between different languages (e.g. BPMN+UML)
• Matrix allow to consider all possible connections

Views Alignment。

Viewpoints and Visualisation。

• No stakeholder (except enterprise architects) is usually interested in the whole architecture
• Stakeholders need specific views of the architecture

View (IEEE)
work product expressing the architecture of a system 
from the perspective of specific system concerns

• The view a stakeholder wants derives from the goal and their current knowledge and their domain
• Specification of a view is expressed by means of a viewpoint

Viewpoint is defiend as (IEEE):
work product establishing the conventions
for the construction, interpretation and use
of architecture views to frame specific system concerns

Viewpoints and Visualisation。

• In Nato Architecture Framework, a viewpoint is referred to as sub-view

• View is what you see, viewpoint is from where you are looking

• A view contains a subset of elements of the model

• Ideally a change in one view result in a change in a model which in turn should update other views

• Present in NAF in Sparx Enterprise Architect

Architecture Concept。

Abstraction

• Generalization
• Striping out structural or behavioural aspects

Architecture Model

• Model abstracts from reality
• The elements which choose to depict depends on the goal
• Model of London Tube for a commuter will be different form a model for Engineers and drivers
• We create models in order to:
  • understand reality
  • predict the future
  • design a new product/service (i.e. modify reality)

Model Elements and Modelling Concepts

• Modelling Concepts described by a framework do not have any concrete elements
• They are usually described in Ontologies and patterns
• Examples:
  • using SOA instead of batch processing
  • always use asynchronous calls

Visualization vs Model。

• Model usually is not visual (XML)
• Graphs, charts and pictures are not the model, they are just the visualization of the model
• Model itself is also refereed to as the content

Visualization vs Model。

One Model Element - Two Shapes

Visualization vs Model。

Semantics

• Two shapes in the examples above mean one thing i.e. the actor
• This common meaning is called semantics
• Semantics refers to the effect of the thing itself rather than its shape
• In Human Languages, the semantics refers to the meaning as oppose to syntax

Semantic model vs Symbolic model

• Symbolic model, refers to concrete objects of the reality (UML objects)
• Semantic model, an abstractions, an interpretation of a symbolic model (UML classes)

Ontologies。

http://www.mod.uk/NR/rdonlyres/FD9A4CC8-7F27-4042-BF23-69F9EC4978A4/0/20090203_Ontologies_and_their_Use_MODAF_V1_0_U.pdf