Download CATE2004_Presentation

New Tools In Education
Minjun Wang
Department of Electrical Engineering and
Computer Science
Syracuse University, U.S.A
[email protected]
Outline
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The Big Picture
Collaboration Architecture
The Master Client Application
The Participating Client Application
The Event Models
Narada Message Broker
Instant Messaging Web Services
Metadata and On-demand Education
The Big Picture
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Collaborative PowerPoint applications for distance education, elearning, and online conferencing
• One of which is a Master client, the others are participants
• The presentation files are deployed or downloaded beforehand to the
hosts of both master and participants clients, and in the same
directories. The MS PowerPoint is installed on all the hosts.
• Use small text-based event messages to communicate between the
master and participants, compared to image data communication as in
Shared Display; thus lower network traffic and improve performance.
• The Master client captures events and sends the event messages to
participants during its presentation; the participants then render and
share the presentation screens synchronously with the master.
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Narada Message Broker as the underlying message
communication system
• It transmits event messages between the collaborative PowerPoint
applications’ master and participant clients
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Web Services as building blocks of collaborative applications
• Instant Messenger Web Services
• Event metadata as Web Services and on-demand education
Collaboration Architecture
NaradaBrokering Message Service
User
1
User
2
User
n
Master
Client
Sink
Connectable
Object
The Master Client Application (1)
The master client is the one that captures events
during a PowerPoint presentation and sends
messages to participating clients for rendering.
Technologies used:
 Automation enables applications to expose
functionality through interfaces, which can be
reused by other applications through wrapper
classes.
 Connectable objects manage Connection Point
objects where events are defined, and therefore
are the event source.
The Master Client Application (2)
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The sink interface is where the handlers of events
are implemented; the Master client handles
events fired from the connectable object through
the sink.
The Participating Client Application
(1)
The participating client is the one that
receives messages from Narada message
broker, and renders the presentation
display.
Technologies used:
 JNI (Java Native Interface)
Cooperation between Java and C/C++
 Wrapper Classes, Dispatching and
Automation.
The Participating Client Application
(2)
The cooperation between the message broker and
the participating client, and the mechanism of it.
The Event Models (1)
Three levels of events:
1.
Physical events
mouse over, mouse clicking, keyboard stroking, etc.
2.
Semantic events
meaningful instructions such as change slides, change
windows, etc.
3.
Rendering events
Rendering of presentation displays via automation,
according to the semantic event messages
received.
The Event Models (2)
Events that are
posted in
“EApplication”
interface of
PowerPoint and
that can be
captured and
processed.
Narada Message Broker (1)
It transmits event messages between the collaborative
PowerPoint applications’ master and participating clients
It can be deployed as a Grid in Peer-to-Peer Grids, using
robust, secure, structured and powerful machines and
resources.
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It supports messaging in Peer-to-Peer Grids
It uses a generalized publish-subscribe mechanism
It handles dynamic protocol choice, tunneling through
firewalls
It supports TCP, UDP, multicast, SSL and RTP
It is error tolerate, supports dynamic routing, secure
message, and full scalability.
Narada Message Broker (2)
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It can run in client-server mode like JMS (Java
Message Service) or in distributed Peer-to-Peer
mode like JXTA
It can be used in real-time synchronous
collaborations
Instant Messaging Web Services
(1)
Web Services are building blocks in Peer-to-Peer
Grids computing. Web Services enable
developers to integrate functionality across
businesses and organizations.
1.
The structure of Web Service
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Publish, Find, and Bind
URI (Universal Resource Identifier), WSDL (Web Service
Description Language) and UDDI (Universal Discovery,
Deployment and Integration)
The elements of Instant Message
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XML (eXtensible Markup Language) tags
DOM (Document Object Model) format
SOAP (Simple Object Access Protocol) protocol
Instant Messaging Web Services
(2)
The structure of Web Service in general, and the Instant
Messaging Web Service with the applications in particular
Metadata and On-demand
Education
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Description tags and properties attach the event
messages by using the functions in Instant
Messaging Web Services; these metadata are
saved and accessed by functions of Metadata
Web Services.
A special version of the collaborative applications
inherits the functions of both the master and
participant, and makes use of the Metadata web
services to access the metadata.
Users subscribe to a topic via session servers,
and use the special version to access the
metadata to render and review the sessions once
happened at their own pace. This is used in Ondemand education.
Conclusions
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The Collaborative PowerPoint applications
integrate the master and participating client
processes; cooperate with the NaradaBrokering
message service; leverage the Instant Messaging
and Event Metadata web services, and can be
used in On-demand education.
It can be used in distance learning, lecturing,
conferencing, etc.
It has the strength of small text event message
communication, and thus high performance and
efficiency. Its limitations include it’s hard to use
in hand-held devices like PDAs.
Future Work
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Dynamic generating and deploying
Metadata Web Services with a
session server.
Integrating the Collaborative
PowerPoint applications with
Audio/Video system to bring
multimedia into virtual classrooms.
Improving the animation and sounds
parts of the applications.