Architecture of Computational Science Education Portals

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Architecture of Computational Science Education
Portals
NPACI All Hands MeetingFeb 8 2000Geoffrey Fox

• School of Computational Science andInformation
  Technology (CSIT)495 Dirac Science
  LibraryFlorida State Universitygcf_at_cs.fsu.edu

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Portals in Computational Science Education

• We are discussing Web-based education or portals
  to a virtual university or virtual corporate
  training center and relation to portals to
  computing
• Merrill Lynch predicts that Enterprise
  Information portal market will be 15B by 2002
• So assume that we are building education portals
  in terms of Distributed Educational Objects --
  this is not really an assumption but a statement
  as to language used
• Portals are built as a customizable set of XML
  components ( e.g. Display a thumbnail of the next
  web-page in lecture or run a Particular Program )

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Basic Portal Architecture and Inter Relationships
of Education, Computing and other Portals
EnterpriseInformationPortals fromMerrill Lynch
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Hierarchy of Portals and Their Technology

• Portal Building Tools and Frameworks (XUL,
  Ninja, iPlanet, E-Speak, Portlets, WebSphere,
  www.desktop.com)

Generic Portals
Collaboration Universal Access Security .
Generic Services
User customization, component libraries,fixed
channels
Information Services
Databases .
Enterprise Portals
Quizzes Grading ...
www.computingportals.org
Compute Services
Education Services
Grid Services Visualization ...
MathML etc
Education andTraining Portals
Science Portals
K-12
University
Biology
Chem Egy
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Portal Assumptions

• Portal will be defined by multiple Web Pages made
  up of components defined in (better)portalML to
  define objects, parameters, collaborative
  structure, layout etc.
• XML Pages access Portal components which at least
  today will mainly HTML

Portal Entry
XML
SubPortal1
SubPortal2
SubPortal4
SubPortal3
XML
SubPortal21
SubPortal22
HTML
Page101
Page211
Page212
Page221
Page301
Page401
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Computing Portals will build on General Portal
Standards

• (better)portalML (XUL) -- define the users
  customized portal layout and what they can choose
  from
• define available objects and layout (number of
  columns etc. generalizes ideas in Flow,..,GridBag
  Object layouts in Java AWT)
• e.g. ltportal name gtltcolumns3/gtltportalobject
  modeforced sourcegtltplaceat layoutflow1
  position1 gt ...
• placement of component objects on pages and
  specification of their parameters and location
  e.g. access weather object for suchandsuchcity
  with suchandsuch sensor overlay
• choice of nifty JavaScript or Java index
• rendering preferences such as resolutions and
  universal access
• borders, backgrounds etc.
• Portal building tools will exist for developers
  (architect template for portal i.e.
  differentiate my.NPACI from my.Netscape) and
  users ( specialize portal template )
• Such general tools will be competition for
  specialized systems like WebCT for education

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A Collection of Shared Portal Components
betterportalML document
Web browser
ltsharedportaldefgt . . . lt/sharedportaldefgt
Web page
Regular content
Document Fragments as Shared objects
In W3C DOM, each Web Page (HTML Page)is defined
as a set of Nodes -- You choose which nodes (and
their children) that you wish to share and then
events are exchanged maintaining state
consistency with logic defined by XML page
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Collaborative Portal Architecture
Content Web Server
XMLContent Pages
Shared Event Service
Style Sheet / User Profile Customization Agent
Events Trapped by Browser and shared by Portal
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Each Collaborating Client Receives Events

• Event Stream becomes set of time stamped XML
  messages
• Pager Cell Phone Email Grid Status Messages
• Collaboration Control Messages e.g. New
  Participant Joined
• User Customization specification
• W3C or Java or Microsoft Client Shared Object
  Definition/Update Messages (e.g. Page Scrolled by
  such and such amount done as XML serialization of
  JavaScript Event object)

Real-Time or off-line (i.e. synchronous
or asynchronous)access of events which
implicitly archive any session
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Remarks on Event Subsystem

• Events are messages with typically handlers and
  time stamps
• Any event subsystem is also a messaging system
• email, MPI, audio/video streams, W3C Document
  Object Model, any database updates are built on
  events
• Events are stored in a distributed database (in
  simple cases a queue) supporting necessary
  robustness and performance
• XML is used to represent all event streams
• could store in relational tables
• Must be able to select by key tags such as time,
  source, destination, priority, subject,
  application (multiple tags)
• body of event must be able to store
  (serialized) objects
• Must be able both to store permanently, relay
  synchronously (multicast if needed), replay later

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Distributed Event Subsystem
Java
DistributedServers
DistributedServers
RobustTemporaryActivities
Select/Update
Select/Update
e.g. for routing and caching
e.g. On PC
JavaScript
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Multiple Modes of Collaboration
Sharing Functionality
Temporal Structure

• Temporal Structure
• Synchronous Updates passed on immediately and
  ignored if client not online (Tango, Habanero)
• Pager Updates passed on immediately if client
  available otherwise queued for later delivery.
  General late-arrival support
• Push Updates performed at given time interval
  (New York Times web site is updated every 10
  minutes)
• Asynchronous Client chooses when to access and
  update shared object (You put up a Web Page. I
  eventually look at it)
• Archive Asynchronous record of one of other
  temporal models.
• One should integrate support of all models?

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Collaboration Functionality

• What features are shared and what can be
  customized on each client and how is sharing
  specified and implemented
• Collaboration Unaware No effort needed to make
  application collaborative -- this is shared
  display model of VNC, NetMeeting
• Share desktop or individual windows
• Share user generated events as well as pixels
• Shared text or simple web page
• Collaboration Aware One must explicitly change
  application to specify how each event shared
  (Tango)
• One can make this easier in particular
  application environments such as Javabeans
• Collaboration Semi-aware Shared display plus
  special menus which can be customized --
  Promising Direction
• Collaborative visualization (share 2D or 3D
  Image)
• Quizzes (support general questions within a fixed
  shared infrastructure)
• Whiteboard

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Some Architectural Issues

• Use the browser mainly for rendering and
  capturing user-interaction events it is not a
  robust virtual machine (container) in which one
  can build WebWindows applications
• Run an Apache Server on every PC
• Palm tops are treated as just another browser
• Where do we need to build new infrastructure and
  cannot re-use existing technology as in CORBA
  Ninja E-Speak etc. ?
• Event Service
• Object specification including betterportalML
  properties
• Collaboration with integrated capabilities
• Education and Portal Specific Objects/Tools with
  properties such as special collaboration features
• visualization
• brainstorming and other learners-teachers
  interaction tool