Fundamental modeling concepts: Difference between revisions

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{{Primary sources|date=December 2009}}

'''Fundamental modeling concepts''' ('''FMC''') provide a framework to describe software-intensive systems. It strongly emphasizes the communication about software-intensive systems by using a [[Formal semantics of programming languages|semi-formal]] graphical notation that can easily be understood.

== Introduction ==

FMC distinguishes three different [[diagram]] types:

FMC distinguishes three perspectives to look at a software system:

* compositional structure

* Structure of the system

* dynamic structure

* Processes in the system

* value range structure

* Value domains of the system

The diagram type are [[bipartite graph]]s.

FMC defines a dedicated diagram type for each perspective. FMC diagrams use a simple and lean notation. The purpose of FMC diagrams is to facilitate the communication about a software system, not only between technical experts but also between technical experts and business or ___domain experts. The comprehensibility of FMC diagrams has made them famous among its supporters.

== Compositional structure diagram==

Compositional structure diagrams (also known as block diagrams) show the systems structure as a composition of collaborating system components.

:"There are active system components called agents and passive system components called locations. Each agent processes information and thus serves a well-defined purpose. Therefore an agent stores information in storages and communicates via channels or shared storages with other agents. Channels and storages are (virtual) locations where information can be observed." <ref>[http://www.fmc-modeling.org/notation_reference/ fmc-modeling.org Notations Reference]</ref>

The common approach when working with FMC is to start with a high-level diagram of the compositional structure of a system. This “big picture” diagram serves as a reference in the communication with all involved stakeholders of the project. Later on, the high-level diagram is iteratively refined to model technical details of the system. Complementary diagrams for processes observed in the system or value domains found in the system are introduced as needed.

== Dynamic structure diagram ==

== Diagram Types ==

FMC uses three diagram types to model different aspects of a system:

*'''Compositional Structure Diagram''' depicts the static structure of a system. This diagram type is also known as FMC Block Diagram

*'''Dynamic Structure Diagram''' depicts processes that can be observed in a system. This diagram type is also known as FMC Petri-net

*'''Value Range Structure Diagram''' depicts structures of values found in the system. This diagram type is also known as FMC E/R Diagram

All FMC diagrams are bipartite graphs. Each [[bipartite graph]] consists of two [[disjoint sets]] of vertices with the condition that no [[vertex (graph theory)|vertex]] is connected to another vertex of the same set. In FMC diagrams, members of one set are represented by angular shapes, and members of the other set are represented by curved shapes. Each element in an FMC diagram can be refined by another diagram of the same type, provided that the combined graph is also bipartite. This mechanism allows modeling all relevant layers of abstraction with the same notation.

=== Compositional structureStructure diagramDiagram ===

[[File:FMCBlockDiagram.png|thumb|Example of FMC Compositional Structure Diagram]]

Compositional structure diagrams depict the static structure of a system, and the relationships between system components. System components can be active or passive. '''Agents''' are active system components. They perform activities in the system. '''Storages''' and '''channels''' are passive components which store or transmit information.

The image to the right is an example of a compositional structure diagram. It contains the agents ''Order Processor'', ''Supplier Manager'', ''Supplier'', ''Online Shop'' and an unnamed '''human agent'''. Agents are represented by rectangles. The dots and the shadow of the agent ''Supplier'' indicate that this agent has multiple instances, i.e. the ''Supplier Manager'' communicates with one or many suppliers. The so-called human agent represents a user interacting with the system.

The diagram contains the storages ''Orders'', ''Purchase Order'' and ''Product Catalog''. Storages are represented by curved shapes. Agents can read from storages, write to storages or modify the content of storages. The directions of the arrows indicate which operation is performed by an agent. In the diagram, the ''Supplier Manager'' can modify the content of the ''Product Catalog'', whereas the ''Order Processor'' can only read the content of the ''Product Catalog''.

Agents communicate via channels. The direction of information flow is either indicated by arrows (not shown in the picture), by a request-response-symbol (e.g. between ''Supplier Manager'' and ''Supplier'') or omitted (e.g. between ''Order Processor'' and ''Supplier Manager'').

=== Dynamic structureStructure diagramDiagram ===

Dynamic structures are derived from [[petri net]]s.

:"They are used to express system behavior over time, depicting the actions performed by the agents. So they clarify how a system is working and how communication takes place between different agents." <ref name="fmc-modeling.org">[http://www.fmc-modeling.org/notation-referencenotation_reference/ fmc-modeling.org Notations Reference]</ref>

=== Value rangeRange structureStructure Diagram == =

Value range structure diagrams (also known as FMC Entity Relationship Diagrams) can be compared with the [[Entity-relationship model]].

:"[They] are used to depict value range structures or topics as mathematical structures. Value range structures describe observable values at locations within the system whereas topic diagrams allow a much wider usage in order to cover all correlations between interesting points." <ref>[http://www.fmc-modeling.org/notation-reference/ name="fmc-modeling.org Notations Reference]<"/ref>

== References ==

{{Reflist}}

<references/>

*{{cite book

| first= Andreas

| last = Knoepfel

| coauthors author2= Bernhard Groene, |author3=Peter Tabeling

| year = 2005

| url = http://fmc-modeling.org/fmcbook/

| title = Fundamental Modeling Concepts - Effective Communication of IT SystesSystems

| publisher = Wiley

| id = 0-470-02710-X

}}

== LinksExternal links ==

* [http://www.fmc-modeling.org/ FMC Homepagehome page]

* [http://www.fmc-modeling.org/fmc_stencils/ FMC-Stencils for MS-Visio]

*[http://www.fmc-modeling.org/intervista FMC-Coaching & Training]

*[http://www.alternative-softwaresystemtechnik.de]

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[[Category:Data modeling]]

[[Category:Data modeling languages]]

[[Category:Specification languages]]

[[Category:Modeling languages]]