1. Collaboration Systems
11/9/2018
Collaboration Systems
Prasun Dewan
Department of Computer Science
University of North Carolina
CB 3175 Sitterson Hall
Chapel Hill, NC
11/9/2018
290-63:Overview

2. Definition Oxford: Work jointly esp at literary or artistic production
Malone: helps people work together more effectively
Lynch et al: makes users aware they are part of a group
Wells: software and hardware for shared interactive environment
Ellis: supports groups engaged in a common task and provides an interface to shared environment
Peter & Johnson-Lenz: computer-mediated culture, intentional group processes plus supporting software
Johansen: specialized computer aids for collaborative work groups
Winograd: state of mind
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3. Potentially Real-Time
Definition
Collaborative
Application
Same output?
Symmetric?
N-User?
I/O
I/O
Coupling
User 2
User 1
Potentially Real-Time
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4. Traditional Collaborative Applications
File
Mail
Talk
send
User 2
receive
User 1 hi
hello
User 2
User 1
save
User 1
User 2
load
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5. Benefits: Towards Being There
Face-to-Face
Interaction
Computer-Supported
Interaction
Network
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6. Gesture Cam: Remote Surrogate
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7. Benefits: Beyond Being There
Face-to-Face
Hollan & Stornetta ‘92
Interaction
Computer-Supported
Interaction
Network
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8. Action Workflow Director Manager 2 Schedule Interview
Status By Candidate Workflow Step 3 1 4
Manage Review
Manager
Director 7 10
Manager
Technical Directors
Submit Evaluation Form 5 6
Director
Manager
Declare Assessment 9 8
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9. Combining Both Goals?
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10. View controls manipulated concurrently
Phantom controls associated with concurrency and access control
View Divergence
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11. Collaboration vs. Virtual Environments
Shared Whiteboard
Nanomanipulator
Remote VE
Collaborative Applications VE
Immersive VE
Telepresence
Colab. Nanomanipulator
Asynchronous/ Face-to-face Collaboration
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12. Collaboration vs. Real-Time & Distributed Apps.
Factoring Prime Numbers
Audio/Video Conferencing
Multi-Mouse Whiteboard
Distributed Applications
Real-Time Applications
Collaborative Applications
Shared Whiteboard
Colab VE
Lotus Notes
Embedded Systems
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13. Collaboration vs. Mobile Apps.
Disconnected Shared Editing with Syncing
Disconnected Editing with Syncing
Collaborative Applications
Mobile Applications
Connected Shared Interaction
Connected Interaction
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14. Relationship with Object-Oriented and User Interface- Technology
Interactive Applications
Collaborative Applications
O-O Applications
Beans
Model-View-Controller-Coupler, Jitter Manager, ...
Collaborative Beans
Model-View-Controller
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15. Traditional System Aspects
Applications
Existing
Shared Screen
Interoperability
FC vs. CC
Extensibility/Composability
Applications
Telepointer Jitter
Performance/Resource Management
Functionality/Abstraction
Coupling
System Support
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16. Views of Collaboration Systems
Ensure actual needs met.
Conceptual depth, avoid duplication.
Build on existing knowledge.
See integrated sets of features
Problems
Issues
Disciplines
Systems :
Applications and Infrastructures
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17. Problems: Application Areas
Business Management
National Collaboratory
Software Engineering
Engineering/Design
Writing
Decision making, business processes, monitor state.
Connected labs.
Team development
Just in time VR-based
Distributed co-authoring.
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18. Problems: Application Areas
Education
Medicine
Air Traffic Control
Command and Control
Games/Casual Interaction
Any complex task!
Distance presentation, remote lab., colab projects
Distance, sharing, workflow
Coordinate controllers
Coordination
Sharing of information/actions
Is collaborative
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19. Generic Tasks Social Interaction Information Exchange Presentation
Consulting
Comment/Discuss
Compose Artifact
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20. Generic Tasks: Product Life Cycle
Design
Implementation
Debugging/Testing
Inspection/Review
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21. Specific Experimental Tasks
Annotate/discuss research article/software specs/video
Present lecture to remote and local audience
Rank job candidates
Choose videos to rent, take on road trip
Get status report on action items and feedback from each participant
Choose name for new game
Search for shopping list online
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22. Views of Collaboration Systems
Problems
Issues
Disciplines
Systems: Applications and Infrastructures
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23. Issues: Semantics
Session Management: How do distributed users create, destroy, join, and leave collaborative sessions?
Single-User Interface: What are the application semantics if there is a single user in the session?
Coupling: what feedback does a user receive in response to the input of another user?
Access Control: How do we ensure that users do not execute unauthorized commands?
Concurrency Control: How do we ensure that concurrent users do not enter inconsistent commands?
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24. Issues: Semantics (Contd.)
Process Control: How do we ensure that users follow prescribed group processes?
Merging: How do we merge concurrent commands entered by different users?
Undo/Redo: What are the semantics of undo/redo in a collaborative session?
Awareness: How are users made aware of ``out of band'' activities of their collaborator?
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25. Issues: Implementation
Objects: What kind of objects are composed in a collaborative application?
Collaboration Awareness: Which of these objects are collaboration aware and how are these objects integrated with existing, collaboration-unaware objects?
Layers: How are these objects arranged in layers?
Concurrency: How is the application decomposed into concurrent threads?
Distribution: How are the application objects placed in different address spaces and hosts?
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26. Issues: Implementation (Contd.)
Replication/Migration: Which of these objects are centralized and which are replicated? Which of the centralized objects can migrate?
Display Consistency: How to ensure actions are executed in the same order on computers that share them?
Real-Time Support: What kind of services are provided to ensure real-time interaction with tolerable jitter and latency?
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27. Views of Collaboration Systems
Problems
Issues
Disciplines
Systems: Applications and Infrastructures
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28. Computer Science Disciplines
Operating Systems
Database Management Systems
Programming Languages
User Interface Systems
Software Engineering
Distributed file, memory, scheduling, “OS-based” IM
Concurrency Control, Recovery
Shared object constructs
I/O distribution of window systems, toolkits
Application area, process control, patterns
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29. Views of Collaboration Systems
Problems
Issues
Disciplines
Systems: Applications and Infrastructures
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30. Systems: Applications
RTCALendering
Cognoter whiteboard
CES (Transaction-based Collaborative Editing System)
Grove Outline Editor
Information Lens Typed
Coordinator Speech-Act Workflow
Quilt Editor Annotations
IBIS Discussions
Video Walls
Hydra
GroupDraw optimistic CC
PREP Diff-based Editor
MUDs (Multiuser Dungeons)
DIVE (Distributed Interactive
Virtual Environment)/ MASSIVE
MIT (Sarin & Greif)
Xerox (Stefik et al)
MIT (Liskov)
MCC (Ellis)
MIT (Malone)
Stanford (Winograd)
Bellcore (Leland)
Xerox (Abel)
U. Toronto (Buxton)
U. Calgary (Greenberg)
CMU (Neuwirth)
Xerox (Curtis)
Sweden (Fahlen)/ Nottingham (Benford)
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31. Systems: Infrastructures
NLS (Engelbart ’68)
Colab (Stefik ’85)
VConf (Lantz ‘86)
Rapport (Ahuja ’89)
XTV (Abdel-Wahab, Jeffay & Feit ‘91)
Rendezvous (Patterson ‘90)
Suite (Dewan & Choudhary ‘92)
TeamWorkstation (Ishii ’92)
Weasel (Graham ’95)
Habanero (Chabert et al ‘ 98)
JCE (Abdel-Wahab ‘99)
Disciple (Marsic ‘01)
Post Xerox
Xerox
Stanford
Bell Labs
UNC/ODU
Bellcore
Purdue
Japan
Queens
U. Illinois
ODU
Rutgers
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32. Systems: Products VNC (Li, Stafford-Fraser, Hopper ’01) NetMeeting
Groove
Advanced Reality
LiveMeeting (Pay by minute service model)
Webex (service model)
ATT Research
Microsoft
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33. Database Transactions
Multiple Views
Coupling
Issue
Cognoter
Application
WYSIWIS Interaction
Database Transactions
Discipline
Infrastructure
App. Area
Task
NetMeeting
Software Engineering
Design
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34. Course Goals State-of-the-art Project Applications Infrastructure
Shared Word, Browser
Infrastructure
Groove, Shared Objects
Project
Writing
Integrate with 291
Programming
Integrate with 243/RAship
Presentation
Research
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35. Projects Infrastructure-based Application-/usage- based 11/9/2018
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36. Infrastructure-based
Replication vs. centralization
Existing system can change it dynamically.
Hypothesis: Transition to centralized when conference gets less interactive and larger
Dynamic policies for transitions
Formal performance model
Shared layer
VNC and NetMeeting share different user-interface layers
Benefits of different sharing different layers.
Can we dynamically change shared layer?
Dynamic policies, performance model
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37. Infrastructure-based
Scheduling
Feedback vs. Feedthrough processing
Give sufficient time to both using proportional scheduling.
Energy-aware collaboration
Energy dissipation a function of amount and rate of information communication
Can study and adjust the coupling (send summary information in batches)
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38. Infrastructure-based
Locking
Many locking schemes
Lock whole spreadsheet vs. individual cell.
Provide one comprehensive mechanism.
Partly designed but not implemented.
Lock-free Consistency management
Locking ensures displays are consistent – no race conditions.
Consistency without locks – operation transformation
Called optimistic CC - misnomer
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39. Infrastructure-based
Context-specific presence
Can synchronously monitor idle time.
Can synchronously monitor every input in shared apps.
Synchronously summarize application-specific information
E.g. whose mail are you reading?
Access control
Needed because we collaborate
But it is a pain
Let us collaborate on setting access control.
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40. Application-based Qual scheduler TA/RA Matcher Automatic did not work.
Semi-automatic, collaborative.
Students enter courses and time constraints
Faculty members enter expertise and time constraints
Schedulers form committees and assign times based.
System checks qual constraints met.
TA/RA Matcher
Students and faculty enter preferences.
Administrators can see all data.
Students and faculty can see filtered data.
E.g. one on one matches.
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