Nicolaescu, P., Derntl, M., Klamma, R.: Browser-Based Collaborative Modeling in Near Real-Time. In Proceedings of 9th IEEE International Conference on Collaborative Computing: Networking, Applications and Worksharing (CollaborateCom 2013). Austin, TX, USA: IEEE (2013)

1. 9th IEEE International Conference on Collaborative
Computing: Networking, Applications and Worksharing
Austin, Texas, United States
Browser-Based Collaborative
Modeling in Near Real-Time
Petru Nicolaescu, Michael Derntl, Ralf Klamma
RWTH Aachen University
Advanced Community Information Systems (ACIS)
{lastname}@dbis.rwth-aachen.de
Lehrstuhl Informatik 5
(Information Systems)
Prof. Dr. M. Jarke
I5-KRNK-0713-1
This project has been funded with support from the European
Commission. This presentation reflects the views only of the
authors, and the Commission cannot be held responsible for any
use which may be made of the information contained therein.
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.

2. Lehrstuhl Informatik 5
(Information Systems)
Prof. Dr. M. Jarke
I5-KRNK-0713-2
Responsive
Open
Community
Information
Systems
Community
Visualization
and
Simulation
Community
Support
Community
Analytics
Requirements
Engineering
Web Analytics
Web Engineering
Advanced Community
Information Systems (ACIS)

3. Agenda
Motivation
 Background and related work
 System design & implementation
 Evaluation
 Conclusions and outlook

Lehrstuhl Informatik 5
(Information Systems)
Prof. Dr. M. Jarke
I5-KRNK-0713-3

4. Motivation

Computer supported near real-time (NRT) collaboration
–
–
–
–

Technology availability (e.g. XMPP, WebRTC)
Large-scale adoption of collaborative systems
Enables higher productivity
Improved results as output
Support communities of practice with collaboration
technologies beyond Google Docs
– Communities reluctant to adopt NRT collaboration
– Case study: enabling co-design support for teacher communities
by redesign of IMS Learning Design stand-alone applications

Lehrstuhl Informatik 5
(Information Systems)
Prof. Dr. M. Jarke
I5-KRNK-0713-4
Framework for NRT collaborative modelling
OpenGLM [24], COLLAGE [8], RELOAD [9]

5. IMS Learning Design(IMS LD)
Authoring
A specification used to describe a “learning design” of
a “unit of learning”
 Describes the teaching-learning process of a unit of
learning (a course, a seminar, etc.)
 Metis project

– supporting co-design for communities of practitioners
using authoring tools (e.g. collaborative learning)

Lehrstuhl Informatik 5
(Information Systems)
Prof. Dr. M. Jarke
I5-KRNK-0713-5
Three levels of implementation
– Level A: core elements
– Level B: adds control of properties and conditions
– Level C: adds notification to level B

6. Problem Identification
Lehrstuhl Informatik 5
(Information Systems)
Prof. Dr. M. Jarke
I5-KRNK-0713-6

7. Real-time Collaborative Editing

Synchronous editing independent of the location of the
users
– Every user is aware of actions of his collaborators
– Editor responsiveness similar to single-user applications
– Consistency maintenance


Inconsistencies caused by divergence or causalityviolation [11] (Sun et al., 1998)
Two approaches for consistency preservation
– Conflict prevention (Xue et al., 2000)
– Conflict resolution [11] (Sun et al., 1998)

Lehrstuhl Informatik 5
(Information Systems)
Prof. Dr. M. Jarke
I5-KRNK-0713-7
Architectures
– Centralized architecture (client/server)
– Decentralized architecture (peer-to-peer)

8. Related Work

IMS LD authoring tools
Tool
NRT Collaboration
Async. Sharing
ReLoad [9]
Desktop
N/A
N/A
ReCourse [23]
Desktop
N/A
N/A
OpenGLM [24]
Desktop
N/A
+
WebCollage [8]

Application Type
Web-based
N/A
+
Near real-time collaboration systems
System
Type
NRT Collaboration
Apache Wave [17]
NRT collaboration platform
Federated
Etherpad (etherpad.org)
Collaborative text editor
Client - Server
Google Real-time API
Client-side collaboration APIs
Client - Server
GROVE [16]
Collaborative text editing system
Client - Server
OpenCoWeb
Open-source NRT collaboration framework
P2P / Client-Server
(developers.google.com/drive)
Lehrstuhl Informatik 5
(Information Systems)
Prof. Dr. M. Jarke
I5-KRNK-0713-8

9. Key Contributions

SyncLD: Web-based NRT collaborative IMS learning
design authoring tool
– Web-based application
– NRT concurrent editing in a decentralized
context based on open-source software
and Operational Transformation (OT)
– Visual modelling
– Use case for NRT collaborative modelling

Lehrstuhl Informatik 5
(Information Systems)
Prof. Dr. M. Jarke
I5-KRNK-0713-9
Evaluation of usability for the Web-based
synchronous learning design authoring

10. ROLE Framework
Web widget (Collaborative Web Component)
Lehrstuhl Informatik 5
(Information Systems)
Prof. Dr. M. Jarke
I5-KRNK-0713-10
Space (shared by multiple users)
EU FP7 ROLE Project
http://role-sandbox.eu/

11. SyncLD



Multi-user chat and
presence awareness
(based on ROLE SDK)
Visual modelling for
activities
Tree structure and
property editing available
–
–
–
–
–


Lehrstuhl Informatik 5
(Information Systems)
Prof. Dr. M. Jarke
I5-KRNK-0713-11
Activities
Environments
Roles
Role-parts
Resources
NRT property changes
NRT shared editing for
text-based fields

12. SyncLD Architecture
Lehrstuhl Informatik 5
(Information Systems)
Prof. Dr. M. Jarke
I5-KRNK-0713-12

13. Implementation

XMPP
– Suitable protocol for NRT communication
– Multiple extensions available (publish subscribe, multi-user chat)
– Client and server support (Smack, Strophe, Openfire, ejabberd)

Open source ROLE SDK based on Apache Shindig
– User management
– Personal and collaborative widget space management
– XMPP-based multi-user chat

Lehrstuhl Informatik 5
(Information Systems)
Prof. Dr. M. Jarke
I5-KRNK-0713-13
Inter-widget communication (IWC)
– Local IWC based on HTML5 Web Messaging API
– Remote IWC based on XMPP Publish Subscribe XEP
– Strophe.js (XMPP over Bosch and WebSockets)

14. Operational Transformation (OT)

OpenCoWeb framework
– Javascript OT peer to peer client-side library
– Modifications to integrate with the ROLE infrastructure
and to support the IMS LD model
Lehrstuhl Informatik 5
(Information Systems)
Prof. Dr. M. Jarke
I5-KRNK-0713-14

15. Operations and the OT Engine
Lehrstuhl Informatik 5
(Information Systems)
Prof. Dr. M. Jarke
I5-KRNK-0713-15

16. User Evaluation

5 evaluation sessions within the METIS project
–
–
–
–
–

Predefined authoring scenario
4 steps
3 users per session
1 IMS LD authoring expert
Concurrent model modifications
Questionnaire
– 7 multiple choice questions
– Open questions

Lehrstuhl Informatik 5
(Information Systems)
Prof. Dr. M. Jarke
I5-KRNK-0713-16
Targets
– Experience synchronized Web-based collaborative IMS LD
authoring while increasing the chance of concurrent edits
– Usability and usefulness of the tool
– Compare the output for consistency

17. User Evaluation Results
Lehrstuhl Informatik 5
(Information Systems)
Prof. Dr. M. Jarke
I5-KRNK-0713-17

18. Technical Evaluation & Challenges

ROLE messaging infrastructure for NRT collaboration
setting
OT Engine performance (consistency preservation)
Integration of the open source projects

Challenges


Lehrstuhl Informatik 5
(Information Systems)
Prof. Dr. M. Jarke
I5-KRNK-0713-18
– Awareness for multiple users
– Late-join support
– Import functionality

19. Conclusions and Future Work

SyncLD
– Supports NRT collaborative editing of learning design models and
was perceived highly useful by designers
– Open source integration for enabling NRT collaboration
– XMPP-based NRT messaging infrastructure
– OT client framework for ensuring data integrity and consistency
– Web-based authoring better perceived than desktop

Lehrstuhl Informatik 5
(Information Systems)
Prof. Dr. M. Jarke
I5-KRNK-0713-19
Future work
– Potential integration with the Integrated Learning Design
Environment (ILDE) in the METIS project
– Awareness widget and activity tracker
– Provide nudges for collaboration support
– Abstraction of the NRT collaboration framework for arbitrary models
using flexible modeling processes