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Nov 5, 2013 (3 years and 11 months ago)

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Coordinating Multiagent
Applications on the WWW: A
Reference Architecture

An article by Paolo Ciancarini, Robert Tolksdorf, Fabio Vitali,
Davide Rossi, and Andreas Knoche


Reviewed by Odd Petter Slyngstad for DT 8107 Distributed
Systems, 13/10/2004

Introduction


Original web had no support for multi
-
user
interactive apps


The authors have developed PageSpace, a
reference architecture for coordinating
multiagent apps on the WWW

Programming the WEB

Programming the WEB (2)


A) Web Servers: CGI
-
script


B) Web Clients: Applet, RealAudio


C) Middleware activity


(PageSpace can support all three)

Coordination Technology for the
Web


Important issues:


Agent synchronization


Agent communication


Agent initiation/start


Use coordination technology to solve;
Linda
-
like (details provided in article)


Coord’ (2)


Contrasting Linda to PVM, Linda is better
because it provides:


Uncoupling of agents via tuplespaces


Associative addressing by tuple type


Focus on coordination only


Coordination through shared tuplespaces (both
client and server)

Next, PageSpace….



PageSpace Architecture

Provides:



applications are comprised of agents



multiple user access



transparent application distribution



application interaction



dynamic and evolvable configuration of

users, applications and hosts

more PageSpace


Agent types:


User interface agents


Homeagents


Application agents


Gateway agents


Kernel agents

Implementation of PageSpace


Jada provides the basic coordination technology
(extends Java and Linda)


access to shared object
spaces


Laura provides service interoperability


based on
Linda, but with enhanced tuple
-
space into service
-
space concept (forms, shared by all agents).

Kernel Agents in PageSpace

yet more PageSpace


Prototype extended to support distributed
PageSpaces (scalability


loose federation)


Fault tolerance


“no effect on PageSpace”


Mobility


logical location


An example of how to design an application
using PageSpace is presented (ecommerce)

Related Work and Conclusion


Other Linda
-
like approaches:


Bauhaus, Javaspaces


Conclusion:


PageSpace integrates


Web technology


communication + presentation


Java technology


uniform host language


Linda
-
like


simple tool for agent activity
description and control