1. A Plug-In Architecture for Graph Based Collaborative Modeling Systems
Niels Pinkwart

2. A Plug-In Architecture for Graph Based Collaborative Modeling Systems
Sharing and commenting of resources as a basic means to support learning
Representation modes of these resources differ
Frequently used mode for resources and means of commenting: graph based

3. A Plug-In Architecture for Graph Based Collaborative Modeling Systems
Augmentation of argumentation tools: ”Collaborative Mind Tools“
Shared computational objects to think (work) with
Enriched with rules and interpretation patterns
Semantic processing of information
Promising and easily possible: integration with modeling languages

4. A Plug-In Architecture for Graph Based Collaborative Modeling Systems
Cool Modes (Collaborative Open Learning and Modeling Environment)
Central aims:
Means to mix different externally defined conceptual representations; plug-in domain semantics
Work without loosing domain or social context
High degree of flexibility (also for cooperation) without loss of processing power

5. A Plug-In Architecture for Graph Based Collaborative Modeling Systems

7. A Plug-In Architecture for Graph Based Collaborative Modeling Systems
System Evaluation
Single plug-ins evaluated in school settings
Questionnaire for extension mechanism planned
Outlook
Model transformations
Metadata and awareness components

8. A Plug-In Architecture for Graph Based Collaborative Modeling Systems
Plug-Ins (dynamic use)
System
structure
Synchronisation: MatchMaker
Workspaces (shared)
intra-tool
interoperability

9. A Plug-In Architecture for Graph Based Collaborative Modeling Systems
Reference Frames: Principles
Encapsulate semantic units / languages, ”microworlds“ that can be mixed
Offer shareable entities for work (or: thinking)
Contain objects, relationships, constraints and interpretation patterns
Have a UI that relies on direct manipulation
Are externally defined and ”pluggable“

10. A Plug-In Architecture for Graph Based Collaborative Modeling Systems
Reference Frames: Structure
Realisations:
- Code based
(Java)
- Data based
(XML)

11. A Plug-In Architecture for Graph Based Collaborative Modeling Systems
Reference Frames: XML example (Petri Nets)
<ReferenceFrame>
<TemplateClass>DefaultReferenceFrame</TemplateClass>
<Objects>
<Node>
<ClassRef>PlaceNode</ClassRef>
</Node>
<ClassRef>TransitionNode</ClassRef>
<Edge>
<ClassRef>PetriEdge</ClassRef>
</Edge>

12. A Plug-In Architecture for Graph Based Collaborative Modeling Systems
Reference Frames: XML example (Petri Nets)
<ReferenceFrame>
<TemplateClass>DefaultReferenceFrame</TemplateClass>
<Objects>
<Node>
<ClassRef>PlaceNode</ClassRef>
</Node>
<ClassRef>TransitionNode</ClassRef>
<Edge>
<ClassRef>PetriEdge</ClassRef>
</Edge>

13. A Plug-In Architecture for Graph Based Collaborative Modeling Systems
Reference Frames: XML example (Petri Nets)
<Objects> …
<Rule Message=“It is not allowed to draw ...”>
<EdgeRule weight=“0”>
<NodeRef>PlaceNode</NodeRef>
<EdgeRef>PetriEdge</NodeRef>
</EdgeRule></Rule>
<Metadata>
<Name>Petri Net Frame</Name>
<Icon>petri32.gif</Icon>
<Package>info.collide.coolmodes.plugins.petri</Package>
</Metadata>
</ReferenceFrame>

14. A Plug-In Architecture for Graph Based Collaborative Modeling Systems
Reference Frames: XML example (Petri Nets)
<Objects> …
<Rule Message=“Do not connect Places to Places”>
<EdgeRule weight=“0”>
<NodeRef>PlaceNode</NodeRef>
<EdgeRef>PetriEdge</NodeRef>
</EdgeRule></Rule>
<Metadata>
<Name>Petri Net Frame</Name>
<Icon>petri32.gif</Icon>
<Package>info.collide.coolmodes.plugins.petri</Package>
</Metadata>
</ReferenceFrame>

15. A Plug-In Architecture for Graph Based Collaborative Modeling Systems
Reference Frame based interpretation : How does Cool Modes analyse user-generated structures and how does it react?
Workspace content is a graph (N,E)
Interpretation: Ip(N,E)
Generic information about elements is available to all the Frames
Generic Interpretation by a Frame F: Ipgen (F,N,E)

16. A Plug-In Architecture for Graph Based Collaborative Modeling Systems
Reference Frame based interpretation
Each Frame F has sets Knows(F)  Defines(F).
(NF,EF) largest subgraph of (N,E) with typesIn(NF)  Knows(F) and typesIn(EF)  Knows(F)
Semantically enriched interpretation: Ipsem (F, NF, EF)

19. A Plug-In Architecture for Graph Based Collaborative Modeling Systems
Reference Frame based interpretation
Each Frame F has sets Knows(F)  Defines(F).
(NF,EF) largest subgraph of (N,E) with typesIn(NF)  Knows(F) and typesIn(EF)  Knows(F)
Semantically enriched interpretation: Ipsem (F, NF, EF)
Overall, with set of Frames  and aggregation :

20. A Plug-In Architecture for Graph Based Collaborative Modeling Systems
Reference Frame based interpretation
Events upon node or edge...
Adding
Removal
Movement
Model change
... are distributed to
Neighbours (local)
Reference Frames (global)

21. A Plug-In Architecture for Graph Based Collaborative Modeling Systems
System Evaluation
Several reference frames evaluated in school settings, results used for usability improvement
Questionnaire for evaluation of the extension mechanism itself planned
Outlook
Model transformations
Inter-operability between Reference Frames  going beyond Knows(F)
Metadata and awareness components

22. A Plug-In Architecture for Graph Based Collaborative Modeling Systems
Questions?