Transcript Document

GroupGraph: a
collaborative hierarchical
graph editor based on
the Internet
Helio A. Souza Lima Filho
Celso M. Hirata
Requirements
Development of a graph editor tool:
 hierarchical graph
 allows the collaborative work
 based on the Internet
 portability
Outline
 Modeling, collaborative work, infrastructure
 Editor components
 Restriction model, lock, perception mechanisms, communication
model
 Case Studies
 Final Comments
Modeling
Model: it is a simplified representation of the system being studied, it
includes only the relevant aspects regarding the goal of the study.
Techniques that use graphs:
 Activity Cycle Diagrams (ACD)
 Petri nets
 Automata
Infrastructure: Internet
 Various hosts that share neither memory nor clock
 Each computer owns its own memory and operating system
 Communication by message-passing
 Issues: resource sharing,
performance, and security.
scalability,
reliability,
availability,
Java and Java RMI
Characteristics:
 Object Oriented
 Security
 Portability
Java Platform: JVM e API.
Distributed Shared Data
There are two basic mechanisms: replication and migration.
Issues are transparency, ease of programming, scalability and
performance.
We use the concept of total replication and no migration.
Groupware
CSCW (Computer Supported Cooperative Work): studies and tries to
understand how people work together (both with and without
groupware), and how the computer and related technologies can
be designed to support effective collaborations.
One of the goals of these studies is to construct computer systems
to allow cooperative work.
Real time groupware allows two or more geographically separated
people to work together at the same time through a computerized
environment.
Editor Components
 Server: keeps the a copy
synchronization among clients.
of
the
graph;
controls
the
 Client: owns a copy of the graph; interacts with the user.
 Model of Restrictions: define as the properties for graph editing.
Model of restriction
Allows to configure the graph editor.
 Node selection.
 Properties of the nodes.
 Properties of the edges.
Global Properties
Allows the visualization of the restriction model.
Properties
Exhibit the properties of the node or edge.
Lock mechanism
 To lock it is necessary to select first.
 Node and edge can be selected
 In the current implementation, the lock is for the composite node
Perception Mechanisms
Chat
Telepointers
Communication between the client and server
Case Study 1: Petri net representation of the
dinning philosophers
The Petri net representation: the restriction model
The dinning philosophers: editing
Case Study 2: Interconnection network of switches
Interconnection network: ACD representation of the
switch
Interconnection network: model
Interconnection network: sub-model
Final Comments and Conclusions
Some limitations of the tool:
 Locking mechanism
 Number of users
 Security
 Fault tolerance
Related Work
 GroupSim: software for collaborative discrete event simulation
based on the WWW.
 GroupPlaces: architecture for groupware based on the WWW.
 Graph editors:

Graph Editing Framework (GEF).

aiSee: software for graph visualization.
Future Work
 Integrate with a DBMS
 Integrate with other tools such as software generation and
analyzers
 Support to other types of specifications such as UML
 More elaborated tools for cooperative work