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Conceptual Modeling in UML

Conceptual Modeling in UML. A super-short introduction . by Ambjörn Naeve. amb@nada.kth.se. http://kmr.nada.kth.se. Concept Formation. Aim :. Concept formation helps us . to disregard what is inessential. by creating idealised structures. that focus on what is essential .

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Conceptual Modeling in UML

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  1. Conceptual Modeling in UML A super-short introduction by Ambjörn Naeve amb@nada.kth.se http://kmr.nada.kth.se

  2. Concept Formation Aim: Concept formation helps us to disregard what is inessential by creating idealised structures that focus on what is essential. Example: Point, Line, Plane, ….. in geometry. Efficiency: Efficient concepts disregard as much as possible so that it is noticed as little as possible. “The power of thinkingis knowing what NOT to think about.”

  3. Conceptual Modeling Def: A description of the most important concepts (and their relations) within a specific problem domain is called a conceptual model of the domain. In order to create an efficient conceptual model of a domain you must be able to reduce its complexity. Four important tools in complexity reduction are: • Abstraction disregard • Hierarchy resolution • Encapsulation interface • Modularity partition

  4. calibr ation- pr ocess Two conceptual models of a domain P Adam Eve Adam’s image of P Eve’s image of P

  5. The concept concept Def: A concept is a representation of something that we have experienced or that we can imagine, and which we can apply to the objects that we are aware of. Def: The set of objects that belong to a concept is called the extension of the concept (or its examplesor itsinstances). To identify a concept Def: by observing similarities and differences within a group of objects is called to classifiy the objects.

  6. The concept concept (cont.) Def: The definition of a concept describes its intention, i.e. what qualities (= properties and behaviour) it wants to express and delimit with respect to its surroundings. Def: We say that a concept can be applied to a specific entity (= object = instance) if that entity fullfills the intention of the concept, i.e. the conditions of its definition.

  7. Properties of the concept concept • A concept must always be defined by making use of other concepts. • A concept can be denoted by one or several names (= symbols). • A concept is always idealised, because it contains simplifications that focus on some aspects and disregard others. • The definition of a concept always depends on the context within which it will be used. • The aim is always to disregard the inessential and focus on the essential.

  8. To symbolise a concept Def: Two symbols are called synonyms if they denote the same concept. Example: Customer and client can denote the same concept in a model of a business system. Def: Two concepts are called homonyms if they can be denoted by the same symbol. Example: In mathematics, negation och subtraction are both denoted by the symbol minus (-).

  9. that that Specialization of Instance of that that this Part of Context for Type for Gener alization of that that The hierarchical directions from this to that Unified Language Modeling

  10. UML - a global modeling language • UML (= Unified Modeling Language) is a language for specifying, visualising and documenting conceptual models within many different domains. • UML was developed during 1993 -1997 within the object-oriented software industry as an attempt to unify the 250 different modeling languages that were in use by the mid 1990s. • UML represents a collection of practically tested modeling techniques that have proven to be effective in the description of large and complex systems.

  11. UML: a visual language for concept relations • UML provides a visual language where you can draw the concepts and their relations in different types of diagrams. • The aim is to display how you think about a specific problem domain. • Words pass - images remain!

  12. UML: a visual language for concept relations • Diagrams create an overview. • You get a visible background against which you can discuss and where it is clear how you have been thinking so far. • This • facilitates further development of the conceptual model. • increases the possibilities to “calibrate the model” and reach consensus with respect to what aspects that are important.

  13. aCar Car Type and Class - two synonyms for Concept Def: The concept, whose extension consists of a set of instances and whose intention describes their common structure is referred to (within computer science) as the type or class of these instances Classification of cars expressed in UML: <<isA>> Named Instance Type (or Class) classification arrow

  14. Pen aPen color = red color Pen color write Attributes and operations of a concept Def: The static properties that belong to a concept are called its attributes. UML-example: Def: The dynamic behaviour that belongs to a concept is described by its operations. UML-example: aPen.write( )

  15. Airplane Car Boat driver driver driver owner owner owner wheel wings keel navigate navigate navigate move move move Gen/Spec - a kind of concept relation Different concepts can have common propertiesand operations. Example: These concepts can be regarded as specialisations of a generalised concept.

  16. Vehicle driver owner navigate Airplane Boat Car wings keel wheel move move move Gen/Spec (cont.) Generalisedconcept: Specialisedconcepts:

  17. Vehicle aCar Car Gen/Spec (cont.) aCarisAkindOfVehicle <<isAkindOf>> <<kindOf>> <<isA>>

  18. Car aCar 1 4 1 anEngine Wheel Engine aWheel bWheel cWheel dWheel Aggregation - a type of concept relation An aggregation is a kind of assocation that expresses a whole-part relation between the corresponding instances.

  19. ownership Vehicle Person owned by owns aBoat pelle aCar anna Association - a type of concept relation association 0..1 1 property owner <<isAkindOf>> <<isAkindOf>> <<isA>> <<isA>> link link A link is an instance of an association. An association between two concepts describes limitations in the link strukture between instances of the corresponding type.

  20. ownership 0..2 1 Vehicle Person owner property <<isAkindOf>> <<isAkindOf>> <<isA>> <<isA>> aBoat pelle anna aCar Link limitations are modeled bymultiplicity Every instance of type Vehicle Meaning: is linked to exactly 1 instance of type Person. Every instance of type Person is linked to 0, 1, or 2 instances of type Vehicle.

  21. Vehicle Car :Car Wheel :Wheel Unified Language Modeling is a kind of akind of abstraction of kind of is a a hasa has is apart ofa part of is a a

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