L5: Advanced modelling (english)

Advanced Modelling
i-views University
Part 05: Advanced Modelling

Advanced ModellingAdvanced Modelling
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Today‘s Speaker
Annekathrin Lösche
Knowledge Engineer
intelligent views gmbh

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- Join alternatively by telephone or by dial-in number
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Event-Number: : 844 317 586
Event-Password: hello

Advanced Modelling
Inheritance in Semantic Networks

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Recap: Object-Type Hierarchies - Inheritance
• Properties are defined for types
• Properties can be inherited by connecting supertypes with subtypes
has sub-type
Also known as:
Top / subset
Top / sub type
"Is a"-relation
The attributes and
relations should be
positioned as far up
in the hierarchy as it
is necessary.
location time

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• Properties are defined for types
• Properties can be inherited by connecting supertypes with subtypes
has sub-type
has sub-type
Also known as:
Top / subset
Top / sub type
"Is a"-relation
The attributes and
relations should be
positioned as far up
in the hierarchy as it
is necessary.
location time
location time
location time location time
location time
location time
location time

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• Object Types may have
multiple parent-types
• Objects must only belong to
one object type

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If an employee of an organization is
included in a project, this organization
is also involved in the project.
The same applies to employees of a
part of an organization.

Advanced Modelling
Formal vs. Informal Semantic
Networks

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Informal vs. Formal Semantic Networks
• Noisy data
• Extended queries
• Thematically relevant information
• Personalised work environment
• Deductions and Recommendations

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Informal vs. Formal Semantic Networks
• Noisy data
• Extended queries
• Thematically relevant information
• Personalised work environment
• Deductions and Recommendations
Informal model
Few Types and Relationtypes
Simple Inferencing
Rigid, formal model
Many Types and Relationtypes
Extensive Inferecing

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Informal Semantic Networks
Combination of different types:
Jazz music = Style of Music
Concert = Event
Record labels = Organisation
Music radio = Medium

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Concert = Event

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Concert = Event

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Concert = Event

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Formal Semantic Networks
• Object-type hierarchy is well orderd
and categorised
• Object-type hierarchy levels are of
the same granularity
• Objects belong to the matching
object-type

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Fromal vs. Informal Semantic Networks
informal semantic network
„melting pot“
formal semantic network
„well categorised“

Advanced Modelling
Hierarchical Relations

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Part-Of or Super-/Subtype-Of Hierachy
Should geographical objects
be presented through a part-
of hierarchy or a type
hierarchy?
General rule: object types
should not be modelled as
subtypes if their individual
objects are already part of
other object type‘s individual
objects.

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Part-Of or Super-/Subtype-Of Hierachy
If we can assume a realistic model of geographic structures, i.e. a continent
consists of countries, which in turn includes its cities, this structure would
be translated into a part-of hierarchy with cities that are part of countries
that are part of continents.
Another general rule: If the
sentence „Any city is a country is a
continent“ is true, you should use
a type hierarchy. In this case, „Any
city is part of a country is part of a
continent“ is more appropriate
though, therefore we use a part-of
hierarchy.

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Part-Of or Super-/Subtype Hierarchy
In this case, attributes are the main reason for
choosing a type hierarchy between these objects.
Possible Reasons for another layer:
• Number of subtypes
• “perceived distance/ togetherness” between the
sibling nodes

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Part-Of or Super-/Subtype Hierarchy
Advantages of a new layer:
• Objects with a certain relatedness are closer to
each other (like Hpyertension and Arteriosclerosis)
Disadvantage of a new layer:
• Complicated, artificial inserted Objects (like
Disease of the respiratory system)

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Artificial Objects for Building Hierarchies
• Used for bundling objects in object-
hierarchies

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Artificial Objects for Building Hierarchies
Not recommended because
„other stringed instruments“
is already represented via
object-type

Advanced Modelling
Modelling Process

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Bottom-Up or Top-Down
Start with either
• A model (object and relation types)
• Specific objects
• Queries and rules for assembling information
Most of the time it will be a combination
• Iterative approach
• Quick construction of a prototype
• On the fly changes of the model
• Exploration of the semantic network will join the setup from the beginning

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Keep in Mind while Modelling/ Designing your Network
• The semantic model is supposed to support the search process and automatic combination of
information
• The semantic model should help you to avoid redundancies
• The semantic model is to present facts as precise as possible
• The semantic model should be easy to understand by externals

Advanced Modelling
Objects vs. Attributs

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Relations vs. Attributes - Recommendations on Usage
Use Attributes when:
• Great variety of information and barely any
repetition in values
Use Objects when:
• Many objects share the same „property“/
information
• The information is itself a complex
information with its own properties
Term x
Term x
Synonym
Term y
Term z Synonym

Advanced Modelling
Inferred Relations

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Different Types of Relations
• User Relation
• Relation defined by the user
• Represent any relationship between objects
• Inferred Relation
• Linking several relations together to form a relational pathway

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Inferred Relation
• At least two connected relations can
create a new inferred relation
• It builts a shortcut between objects,
well used paths don’t have to be
defined new every time
• Example: the song Back to Black from
the album Back to Black is connected
to three moods. These moods could
also be connected to the album itself.
An inferred relation defines this
connection.

Advanced Modelling
Ordering Relations and Attributes

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Relations-/Attribute Hierarchy
• Like types, relations can be defined in a hierarchy
• The domain and target domain won‘t be inherited by the
subtypes
• It is possible to create abstract relations
• This hierarchy can be used for
• A better overview
• Which relations are possible between certain types?
• Implications
• Which can be used in structured queries
• Instead of using three different relations (with different domains
and target domains), a grouping relation can combine all three of
them (e.g. Role Is Present on Song)

Advanced Modelling
Extensions and Roles

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Recap: Extensions and Roles
• Objects can only be of one type.
• You have to use extensions with their own relations and attributes if you
want to express additional features.
• Examplary use cases:
• Representation of temporary properties
(position in a company; status of a project)
• Role based permission system

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Recap: Extensions and Roles

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Recap: Extensions
• Objects can have only one
defining type (as opposed to
type!).
• Additional categorisations of
enhancements with own
relations and attributes.

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Recap: Extensions
• Extensions for time-limited roles (position
in a company; Project status)
• Example: Objects of type person will be
extended through:
• Roll bassist
• Roll producer
• Roll composer
• ...
• Changes for the role of the person must
be made only on the role object, not on
all people associated.

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Recap: Extensions
• A person can receive more than one
role at the same time
• Thanks to the extension, new relations
and attributes are available for the
extended object that were not
previously approved by the schema
(for example : Jenny Conlee
"participates in" Allright as
accordionist)
• This connection can not be illustrated
through "normal", separate relations

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Defining an Extension

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Using an Extension
All possible relations
for an object of type
person

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Using an Extension

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Using an Extension

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Using an Extension

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Using an Extension
All possible relations
for an object of type
person and the
extension Musician

Advanced Modelling
Meta-Properties

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Recap: Metaproperties
Meta properties of relations and attributes can be
mapped by attributes
• Ex.: “changed at“, if you want to remember when
somebody changed an e-mail or the membership of a
project
changed at
changed at
is member of

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Recap: Metaproperties
Meta properties of relations and attributes can be
mapped by relations
• Ex.: “changed by”, if you want to remember who
changed the e-mail or the membership of a projectchanged by

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Defining a Metattribute

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Defining a Metaattribute

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Using a Metaattribute
Click right on the
property you want
to add a
Metaattribute to

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Defining a Metarelation

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Defining a Metarelation

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Using a Metarelation
Click right on the
property you want
to add a
Metarelation to

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Advanced Modelling
Remodelling

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Changing the Object Type of Objects
Move all direct objects of an
object-type to anoter type:
Right click on the type that
contains the objects

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Changing the Object Type of Objects
Enter the type you wish to
move the object to
Make sure the type you‘re
choosing is not abstract
The same way you can
„morph“ relations of a relation
type into another relation type
and attributes

Advanced Modelling
Create a New Sub-Network

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• For a better overview it can be usefull to create
a new sub-network
• The sample-network has currently 4 sub-
networks
• Only administrators can create new sub-
networks

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• To see all the sub-networks click on the cog-
symbol and select „Top Types“

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• Name your new-sub-network and you will see it
added to the other sub-networks
• Sub-networks can still use the relations of the
other sub-networks

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Exercises
1. Revisit your Semantic Model from the lesson 1 exercise and think about ways to improve the
semantic network. Explain the changes you conducted and why.
2. Many organisations have more than one site, which can be identified by their street names, street
numbers, zip codes, cities and countries. Additionally, there is quite a high number of organisations
that are supposed to be represented by the model over a long timeframe. Choose a fitting way to
model this situation.
3. An organization employs 2 employees: Tim as am manager and Tom as an assembly-line worker. Two
years ago Tim used to be an assembly-line worker, too (before he got promoted to the manager-
position). Please model the scenario.

Advanced Modelling
Send your questions to:
contact-webinar@i-views.com
Consultation hours: Every Wednesday
Thank you for visiting
i-views University

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L5: Advanced modelling (english)

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