education as a web service technology, experience & futures

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Education as a Web ServiceTechnology, Experience & Futures

Geoffrey FoxChief Scientist Anabas Inc.

Professor of Computer Science, Informatics, Physicsand Director PTLIU Laboratory for Community Grids

Indiana University, Bloomington IN 47404http://grids.ucs.indiana.edu/ptliupages/presentations

[email protected]

04/22/2304/22/23 uri="gxos:/ptliupages/presentations/distedtalkfeb02" email="[email protected]"uri="gxos:/ptliupages/presentations/distedtalkfeb02" email="[email protected]" 222/22/2001 JSUFall97Master http://www.npac.syr.edu [email protected]

1

Programming for the WebProgramming for the WebGeneral IntroductionGeneral Introduction

Course at Jackson State University Spring98 Course at Jackson State University Spring98 and Fall 97and Fall 97

http://www.npac.syr.edu/users/gcf/jsufall97introNancy McCracken

Geoffrey Fox, Tom ScavoSyracuse University NPAC

111 College PlaceSyracuse NY 13244 4100

3154432163

JSU

Syracuse

Teaching Jackson State Fall 97 to Fall 2001

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The Virtual University Motivated either by decreased cost or increased quality of

learning environment Will succeed due to market pressures (it will offer the best

product) Assume that as with text books, only a few pedagogically

excellent teachers will produce lectures; only a few charismatic souls deliver them

“Centers of Excellence” (including “One Professor Virtual University”) are natural entities to produce and deliver classes supported by good technology and rich graphics/multi-media (instruction design)

University acts as an integrator putting together a set of classes where it may only teach some 20% but acts as a mentor to all classes its students take


Courses at Jackson State Taught using Tango/Anabas since fall 97 over Internet twice a

week from Syracuse/FSU/Indiana• Course material same style as online material for in-university

classes• Curricula, Homework, Grading, Facilities done by “me”• Students get JSU NOT Syracuse/Indiana Credit

Jackson State major MSI (Minority Serving) University with many computer science graduates

Do not compete with base courses but offer addon courses with “leading edge” material (Web Technology, modern scientific computing) which give JSU (under)graduates skills that are important in their career

Fall 99 Semester CPS640 offered to 40 students in 5 distant places and separately 40 at Syracuse


What did this lead to? Jackson State students got access to curricula that was not

otherwise available to them Developed quite good Information Technology and

computational science curricula Jackson State faculty acted as mentors in course and now

teach some of material in their own courses and to other MSI colleges• Make rapidly changing and important curricula available to

an MSI network -- could dramatically improve curricula opportunities for MSI students

• JSU has institutional commitment to area Used in High School Java, DoD wide training and Winter

00/01 semester as part of ERDC Graduate Institute Supports migrant teachers -- I have delivered course spring

00 semester from Syracuse, FSU and ERDC, Vicksburg


Saturday Java Academy

http://old-npac.ucs.indiana.edu/projects/k12javaspring99/

04/22/2304/22/23 uri="gxos:/ptliupages/presentations/distedtalkfeb02" email="[email protected]"uri="gxos:/ptliupages/presentations/distedtalkfeb02" email="[email protected]" 77Desktop A/VCommunity A/V: The Access GridPersonal Access Grid + Anabas

Large Room Access Grid

Fall 2001 Technology


Lessons from Past “True” Shared Event flexible but too much work for

most cases Shared Display – nearly always works Shared Export – SVG PDF HTML X3D etc. can be re-

used Integrate synchronous and asynchronous collaboration Do not build into browser as not a reliable or standard

virtual machine Build around uniform publish-subscribe style XML

Event Model supporting archiving, customization, filtering – apply to all collaboration modes

Later we realized need to integrate with Peer to Peer and Web Services (straightforward as XML event model fits these architectures)

04/22/2304/22/23 uri="gxos:/ptliupages/presentations/distedtalkfeb02" email="[email protected]"uri="gxos:/ptliupages/presentations/distedtalkfeb02" email="[email protected]" 99SVG Sharing PC to PDA

PowerPoint can be converted to SVGvia Illustrator or Web export

Batik Viewer on PC


Object Web View of the World “Everything electronic” is a resource

• Computers• Programs• Data (from sensors to this presentation to email to databases)• People

“Everything electronic” is a distributed object “All External Interfaces” are defined in XML whether this is a

property (data-structure) or a method (service, function, subroutine)• We can assume that a data-structure property has getproperty() and

setproperty(value) methods to act as interface • All resources have interfaces

All resources are linked by messages with format and transport protocol to be discussed but as interfaces defined in XML, message structure must be specifiable in XML


The 3 Critical XML Interfaces Data (sort of

dumb) Information User

Rendering

(Virtual) XML Data Interface

Raw Data

Processing

Information/Knowledge

(Virtual) XML Information Interface

Render to XML Display Format

RawResources

Server

Clients

(Virtual) XML Rendering Interface


ResourceDatabase

ResourceSoftware

Software

XMLSkin XML

Skin

MessageOr EventBasedInterConnection

XML Defined Resourcesconnected by XML defined messages

Implementation of resource andconnection may or may not be XML


What is a Web Service A web service is a computer program running on either

the local or remote machine with a set of well defined interfaces (ports) specified in WSDL

In principle, computer program can be in any language (Fortran .. Java .. Perl .. Python) and the interfaces can be implemented in any way what so ever• Interfaces can be method calls, Java RMI Messages, CGI

Web invocations, totally compiled away (inlining) but The simplest implementations involve XML messages

(SOAP) and programs written in net friendly languages like Java and Python

Web Services separate the meaning of a port (message) interface from its implementation – WSDL Interfaces are virtual XML


Role of Web Services Define interfaces of web applications so that computer-computer

interactions are enabled• Defines virtual XML for all system and application services

WSDL is XML versions of Class and Method definitions SOAP is XML version of message UDDI or WSIL catalogs WSDL based services enabling precise

linkage of them ( WSFL and WSCL are candidate linkage languages

Security Catalog

PaymentCredit Card

WarehouseshippingWSDL interfaces

WSDL interfaces


etc.XML WS to WS Interfaces

(Virtual) XML Knowledge (User) Interface

Clients

(Virtual) XML Data Interface

Raw DataRawResources

Raw Data

WSWS

Web Service (WS)

WS

WSWS WS WSWS

Render to XML Display Format

(Virtual) XML Rendering Interface


Some General Grid or Web Services


Some Science Web Services These build on general (community) web services


Education as a Web Service Can link to Science as a Web Service and substitute educational

modules “Learning Object” XML standards already exist from IMS/ADL

http://www.adlnet.org – need to update architecture Web Services for virtual university include: Registration Performance (grading) Authoring of Curriculum Online laboratories for real and virtual instruments Homework submission Quizzes of various types (multiple choice, random parameters) Assessment data access and analysis Synchronous Delivery of Curricula Scheduling of courses and mentoring sessions Asynchronous access, data-mining and knowledge discovery Learning Plan agents to guide students and teachers

http://www.adlnet.org/


UDDI & Content Management Consider content to consist of “curricula pages” and

meta-data We have meta-data stored in LDAP, flat files, UDDI,

databases (Oracle 9i), XML databases, WebDAV, Web page header tags, JMS topics

Content meta-data and content linked by URI. In general content & meta-data stored separately

Managing meta-data is hardest problem – view as federation of multiple independent heterogeneous databases with separate access and lookup services• Each component is a web service supporting query, access,

store etc. UDDI will be replaced by this more general view Most of education is meta-data …….


LCMS as a Web Service For meta-data, just build federated database as a Web

Service• Storage, update, lookup of objects• Registration of different control engines

For content, if W3C DOM and Java API as for SVG and “decent” XHTML browsers, then can wrap DOM as a web service for all interface functions• Can of course do this for IE5 but document object model

unreliable Build collaboration systems as sharing Web Service

interfaces (not COM or other object API)


Integration of XML/Web Services into an Enterprise I

You are the CIO of a little known state’s (call it Xanadu) education system and been tasked to position it as a 2005 leader in technology enhanced education

Your initial review reveals a multitude of incompatible existing information systems distributed over Xanadu’s 50 campuses

Your cradle to grave community education mandate (which got the Governor elected) implies integration of all aspects of education in your information system

You note that performance issues are much less important in this application than interoperability (it currently takes months to get anything done so what's an extra millisecond or so at a WSDL interface) , so even in current primitive/immature state Web services look attractive


Enterprise Web Services II We start a requirements analysis and a catalog of existing “raw

resources”. This will lead to the clean internal XML(WSDL) interfaces XIF and to the external XML interfaces (XEF) to the raw resources

What is Xanadu Internal Framework (XIF) ? We find that The Grid Forum community has defined computing

interfaces which we will adopt to support infrastructure needed for use of simulations and data repositories in curriculum

We find that Microsoft, the Liberty Alliance and the Grid have Security schemes but are relieved that with a little bit of XSLT (transformations) we can map between them and can define authentication & access control as a Web Service

We join the IMS consortium and adopt their standards for learning meta-data and user related information

We adopt the AICC and ADL SCORM standards for “learning objects” (course pages)


Enterprise Web Services III We define Xanadu educational agents which use XIF plus

RDF/DAML-OIL to be able to capture educational goals We expect commercial standards compliant solutions will be

available for most other needed Educational web services We find that we must interface with a dreadful collection of

external raw resources coming from legacy PeopleSoft SAP Oracle and Microsoft products• As our new model is object (XML) and open standards based we build a

separate XII (Xanadu Information Infrastructure) supporting XIF objects We analyze structure of legacy systems and their relation to XIF

and define the external framework XEF which captures much of the raw resources• This XEF Schema is extensible to capture quirks of each legacy system• We build a set of Web services that convert XEF into XIF

We inform vendors that we will only install XIF compliant systems in all future purchases


CollabWS: Collaboration as a Web Service This includes Audio-Video conferencing, Instant

Messengers, shared applications and tools There are basic standards H323 and SIP There are peer to peer collaboration approaches like

JXTA from Sun The various commercial products – Anabas …Centra

…Webex … Groove Networks effectively defines some shared application interfaces

CollabWS defines a superset of collaboration properties and subservices in XML/WSDL

Then you provide several bindings of collabws.wsdl to new transports and old ones (binary H323)


H323 SIP

JXTA


SIPH323 JXTA

H323 JXTA

SIP


A Typical SIP Message REGISTER sip:registrar.biloxi.com

Via: SIP/2.0/UDP 10.4.1.4:5060To: Bob (sip:[email protected])From: Bob (sip:[email protected]);tag=456248Call-ID: [email protected]: 1826 REGISTERContact: (sip:[email protected])Expires: 7200Contact-Length: 0

Initially build a wrapper that accepts such messages and converts to …..


Collaboration as a Web service - now


SIP as XML <sipasxml>

<register> sip:registrar.biloxi.com</register><via> SIP/2.0/UDP 10.4.1.4:5060</via><to> Bob (sip:[email protected]) </to><from tag="456248" > Bob (sip:[email protected]) </from><call-id> [email protected]</call-id><cseq> 1826 REGISTER </cseq><contact> (sip:[email protected]) </contact><expires> 7200 </expires><contact-length> 0 </contact-length></sipasxml>

So this is either an internal format to which we map SIP messages or it is an external format used for Collaboration Web Service


Future Collaboration Web Service


Messaging/Events as a Web Service We can implement messaging subsystem (between

WSDL resources) with either direct messages or by a queued system where you publish messages to queues and subscribe as receiver to particular queues

There are many different publish/subscribe models• JMS is a cluster of central servers• JXTA is a very dynamic Peer to Peer model where pipes are

queues and topics (metadata) are service advertisements One could have different ports in Messaging/Event Web

Service corresponding to the different JMS or JXTA fault tolerance/reliability semantics• Could use JMS as long distance “carrier” between JXTA peers• JXTA provides higher performance than JMS for nearby

recipients


Event Web Service

Filter is mapping to PDA or slow communication channel (universal access) – see our PDA adaptor

Workflow natural as all messages “intercepted” by Event Web Service

Routing illustrated by JXTA Destination-Source matching illustrated by JMS

Web Service 1

(Virtual)Queue

Web Service 2

Destination Source Matching FilterRouting workflow

WSDLPorts

WSDLPorts


Broker Network

Database

Resource

Broker

Broker

Broker

Broker

Broker

Broker

Software multicastP2P: Brokers are clients

Brokers created dynamicallywhen needed for a new cluster of resources


Narada JXTA/JMS Integration http://grids.ucs.indiana.edu/ptliupages/projects/narada/ Is a network of event brokers which can reliably deliver XML

specified events Using openJMS selection module, becomes a distributed or

conventional Java Message Service Linking special JXTA

proxies, it can link JXTA communities

Think of JXTA JMS and“native” Narada as different bindings (ports) in anevent/messagingweb service

http://grids.ucs.indiana.edu/ptliupages/projects/narada/


Peer to Peer Grid

DatabaseDatabase

EventBroker

EventBroker

EventBroker

EventBroker JMS

JXTA

JXTA

Peer to Peer GridCommunity Grid


PDA Collaboration Adaptor


MyProfessor on the PDA


Component –based Portal

Web Services provide a component model for the middleware (see large “common component architecture” effort in Dept. of Energy)

Should match each WSDL component with a corresponding user interface component

Thus one “must use” a component model for the portal with again an XML specification (portalML) of portal component

education as a web service technology, experience & futures

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