2. P ROPERTIES OF C OLLABORATIVE U SER I NTERFACES Prasun Dewan Department of Computer Science University of North Carolina at Chapel Hill dewan@cs.unc.edu

3. 2 COLLABORATIVE APPLICATION U1U2U3 Application User inputs “draw red circle” Coupling A user’s output can be influenced by the input of at least one other user Or a user’s input can influence the output of at least one other user

4. 3 M ANDATORY AND O PTIONAL P ROPERTIES Interactive Distributed Multiuser Collaborative Real-time Collaboration Multi-view User Awareness Optional but typical properties

5. 4 S INGLE -V IEW

6. 5 M ULTI -V IEW : H ORIZONTAL I NPUT

7. 6 M ULTI V IEW : V ERTICAL I NPUT

8. 7 C ONSOLE F EEDBACK Simplex because Architecture Feedback only in console

9. 8 M ULTI V IEW : I NPUT IN ANY UI

10. 9 C HANGES ALL U SER I NTERFACES Distributed? Change in UI?

11. 10 D ISTRIBUTED UI Server Client

12. 11 D ISTRIBUTED UI Server Client Multi-user?

13. 12 M ULTI -U SER I NTERFACE : A LICE T YPES

14. 13 M ULTI -U SER I NTERFACE : A LICE F EEDBACK

15. 14 M ULTI -U SER I NTERFACE : B OB T YPES

16. 15 M ULTI -U SER I NTERFACE : B OB F EEDBACK Collaborative? Non real time?

17. 16 C OLLABORATIVE I NTERFACE : A LICE T YPES

18. 17 C OLLABORATIVE I NTERFACE : A LICE F EEDBACK

19. 18 B OB J OINS No latecomer support

20. 19 A LICE T YPES A GAIN

21. 20 A LICE F EEDBACK

22. 21 B OB T YPES

23. 22 B OB F EEDBACK Real-time Collaborative?

24. 23 R EAL -T IME C OLLABORATIVE : A LICE T YPES

25. 24 R EAL -T IME C OLLABORATIVE : F EEDBACKS

26. 25 B OB T YPES

27. 26 L OCAL AND R EMOTE R ESPONSE User awareness?

28. 27 S UPER COLLABORATIVE : T ELE - POINTER, A WARENESS Features in the Collaborative UI that did not exist in the 1- user UI

29. 28 P ROGRAMMING C ONSTRAINTS Interactive Distributed Multiuser Collaborative Real-time Collaboration Multi-view It should be possible to create each kind of user interface There should be reuse Reuse should be layered User Awareness

30. 29 L AYERING /A WARENESS Single-View Distributed Multiuser Collaborative Real-time Collaboration Multi-view A layer is unaware of layers above Distribution, view, unaware Multi-User unaware Coupling unaware Real-time, user- awareness unaware A layer should be designed to be reused by higher layers User Awareness

31. 30 S UMMARY By definition, real-time and user-awareness implies collaborative, which implies, multi-user, which implies multi-view Typically multi-user applications implies distributed These fundamental and typical implications can be used to create a set of logical layers, with a logical layer stacked on top of layers it implies An implementation goal should be to create actual physical layers that mirror these logical layers, that is, each logical layer should be mapped to one or more separate software layers

32. 31 S UMMARY Real-time does not imply user awareness though in this example we added it on top of user awareness Imagine a counter shared among multiple users that does not give indication of who changed it.