Service-Oriented B-Learning ArchitectureUsing Web Service-Based Intelligent Agents

Nasir Hussain, M. Khalid KhanDept. ofComputer Science, PAFKIET, Karachi, Pakistan

nasirwt(g&vahoo.com, mkhalidkhan(d,gmail com

Abstract-There is no doubt that e-learning has found itsway in our lives. From the very start to the Ph.D. level onecan find e-learning courses every where and all the bignames are supporting it. One thing that is needed to beunderstood is that e-learning is basically the integration ofvarious technologies. Now this technology is maturing andwe can find different standards for e-learning .Newtechnologies such as agents and web services arepromising better results. In this paper we have proposedan e-learning architecture that is dependent on multi-agent systems and web services. These communicationtechnologies will make the architecture more robust,scalable and efficient.

I. INTRODUCTION

In this paper, we have proposed an e-learningarchitecture based on web services and intelligentagents using service-oriented approach. The advent ofInternet gives us challenging new possibilities forteaching and learning. Especially the World Wide Web(www) makes it possible to develop educationalcontent and delivery in a whole new perspective. Inrecent years, the development of online educationalsystems is on high priority for researchers,technologists, engineers and experts. The terms e-learning, web-based learning or hypermedia aidedlearning are interchangeable for online education.

E-learning systems use various tools andtechnologies to establish its existence over World WideWeb. There are various standards and specificationsdeveloped so far. ADL (Advance Distributed Learning)SCORM (Sharable Content Object Reference Model[1] is one of the most renowned models for learningcontent objects. It provides interoperability betweendifferent learning systems by the means of standardizedpackaging, sequencing and communication methods forleaming contents.

To achieve interoperability between differentsystems across the internet, web service technologynow plays an important role. It is mainly use fordistributed web applications that uses communicationprotocol based on 'Simple Object Access Protocol'(SOAP) [2]. It frees the client and server from anyplatform-specific implementation restrictions, allowingmuch greater flexibility in a heterogeneous computingenvironment. We have designed an architecture that isbased on web service based intelligent agents toconsume educational services of each other in e-learning networks and enhance the learning experienceof individual learners, teachers and authors throughuser agent interactions.

The intelligent agents have been suggested as atechnology to deal with challenges such as theincreased need for personalization, high latency,demand for large transfers and disconnected operationsand mainly used in distributed environments [3].

In upcoming section we will discuss about e-learning, in section 3 and 4 we will discuss webservices and intelligent agents respectively. Section 5discusses our proposed architecture. In section 6 wewill discuss benefits of the proposed architecture andsection 7 will conclude our work.

II. E-LEARNING

E-learning or electronic learning is rapidly takingits place 6ver the internet. Use of technology toenhance learning not only involves technologists butauthors, learners, teachers and instructional designersare also taking interest that how one can learneffectively and efficiently. ADL plays an important rolefor e-learning and build SCORM to deploy learningcontents on any Learming Management System thatconforms to SCORM standard. ADL integrates thework of various standards and specifications such as

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IEEE LTSC's LOM (Learning Object Metadata), AICCCMI data model, IMS Content Packaging and manyothers [1]. SCORM provides the foundation of usingstandardized based learning contents that can bedeployed to any LMS and student can be tracked bystandardized way using AICC CMI data model. ADL isnow expanding its e-learning research and currentlyworking on specifications for object repositories,gaming, performance aiding and intelligent tutoringsystems (http:H/www.adlnet.org).

As e-learning technology is distributed in nature, soit need support from distributed intemet technologiesthat can drive it over the World Wide Web. Inupcoming sections we will discuss that how candistributed technologies like web services andintelligent agents play a better role to improve e-learning infrastructure.

III. WEB SERVICE

Online learning is learning via web. In this type ofleaming a learner is connected to the internet andutilizing educational contents through web browsers.As like a person can take some information about acompany from a company's web site; a learner can takea class lecture from e-learning service. Mostly LearningManagement Systems (LMS) can serve learningcontents, search & discovery of contents and coursemanagement etc. There are various vendors of LMS inthe market that supports SCORM standard using itsRun-Time Environment (SCORM RTE) specification.We can also develop architecture for SCORMcompliant LMS using SOAP and .NET XML webservices [8]. Another usage of .NET XML web servicesis in the form of MIT's 'iCampus'(http://icampus.mit.edu) and 'iLab'(http://icampus.mit.edu/ilab).

A learner just not only sees a course material in theform of web page but a learning network providesmuch greater learning facilities to the learner. Themajor advantages of online learning are that it isaccessible anytime and anywhere.

User can access e-learning network anywhere in theworld and take advantage of individualized learning.Online learning can be useful in industries to trainedemployees and enhanced their skill sets; it is useful inuniversities for off campus studies and it fulfills rapidtraining needs for all individuals those who reallywants to utilize e-learning services.

Beside these major advantages e-learning canprovide facilities such as personalization, learningforums, digital libraries, virtual labs, authoringservices, virtual classes and many others. Not onlylearners can take advantages of these services butteachers and authors can also find it useful indeveloping course contents or using it as a referencematerial.

Web service is a technology that has built toprovide various types of services over a web. The mainadvantage of using a web service technology is cross-platform communication. Recently (2005) there are twomajor competitor of web service technology in themarket that is Microsoft and Sun. From implementationpoint of view both using common standards andprotocols, such as Simple Object Access Protocol(SOAP), Extensible Markup Language (XML), WebService Description Language (WSDL) and UniversalDiscovery Description & Integration (UDDI) [4].

SOAP is an XML-based message exchange protocolthat is used to communicate between web services andtheir clients [5]. With the help of this lightweightprotocol we can exchange structured information in adecentralized distributed environment easily.

WSDL provides description of a web service. Eachweb service has WSDL file which is basically an XMLfile that describes a set of SOAP messages and how themessages are exchanged between web services andclients [4].

UDDI is often called yellow pages of web services[4]. A UDDI is a directory of web services that haveXML files describes a business and the services itoffers. We will use UDDI in our architecture to exposeour educational services so other can take advantagesfrom these services.

A. Web Service Infrastructure

In web service-based computing model, both clientand web services are unaware of the implementationdetails. If client wants to consume a web service, it willhave to go through from four steps. These four stepsare directory, discovery, description and data which isalso called wire format [4].

In Figure 1 web service infrastructure is shown.First step (directory), a client tries to search for a web

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service. Directories service such as UDDI provides acentral place to store published information about webservices. Client search that directory and finds a URLof discovery document. In step 2, a client sends requestfor service description document. The server returnsthe discovery document that enables client to knowabout the presence of a web service and its location. Instep 3, client sends request for description of aparticular web service. The service description is sendby server in XML format that specifies the format ofmessages that web service can understand.

UDDI(o other &eclory wco )

WebC

_~~~~~~Figure 1: Web service infrastructure

Finally at last step, client requests the XML webservice and able to invoke its functions. The serversends the required response to a client. To enablecommunication between disparate systems web serviceuse open wire formats. Open wire fornats are theprotocols that can be understood by any system that iscapable of supporting comnon web standards, such asHTTiP and SOAP.

IV. INTELLIGENT AGENT

An agent, intelligent agent or agent-based systemis a software-based computer system that has severalproperties such as; autonomy, social ability, reactivity,goal-directed, mobility and collaboration. Agents areused to make a user tasks easier in a distributednetwork environments [6]. Every agent can performtheir tasks as they programmed for. Agents cancommunicate with user as well as other agents in anetwork. Agents are also helpful to exchange data incross-platform systems.

Mobile or intelligent agents are also software-basedagents that have ability to move in a network. They canmove in network of computers and seeking informationfor their owner or even negotiating and concludingbusiness deals [6].

These intelligent agents can be useful for manyapplications. Mostly intelligent agents are used togather information for user according to his/herdemands and matching user profile (if exists) forprecise results. Another advantage of using intelligentagents for mobile devices is that they can detect thecapabilities of mobile devices such as its memory,storage capacity and processing power so they canwork accordingly [3].

Applications of intelligent agents not limited togeneral information retrieval from network but it canuse for network management [9], electronic commerce,application maintenance and many others. Interfaceagents are one of the types of intelligent agents that arecommonly designed today. It has basically a graphicaluser interface character that has an ability to learnabout user preferences, interests and habits. It caninteract with user audio-visually to maintain userattention towards some task [7].

We used intelligent agents in our e-leamingarchitecture for online education. User may be alearner, teacher or author. For a learner, intelligentagent can find information about his/her learning needssuch as books, courses, virtual classes, labs andlearning forums etc. in a learning network. Teachers'mobile agents can provide information about teachingmaterials, learning contents, books and forums usinguser profile. In our architecture, the applications ofintelligent agent not limited to these areas (as describeabove) but it will also plays an important role tointegrate other e-learning networks capabilities andmake an scalable and interoperable architecture. Toprove our point of view that the use of agent in thesystem will definitely be efficient, we are providinghere some agent properties.

A. Autonomy

"Self-government independence: Branch managershave full autonomy in their own areas" [Oxfordadvanced learner's dictionary]. He decides himselfwhen and under which condition he will perform whatactions. "An autonomous agent is a system situatedwithin and a part of an environment that senses that

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environment and acts on it, over time, in pursuit of itsown agenda and so as to effect what it senses in thefurther"

B. Communication

One of the key properties of agents is the ability tospeak with human (Interface Agents), or with devices.Communication between agents, called languages oftenused are:

* Blackboard: Agents read and write messagesin a shared location (blackboard)

* KQML: Knowledge Query and ManipulationLanguage is a language and protocol forexchanging information and knowledge using"performatives".

* KIF: Knowledge Interchange Format* COOL: structured conversation, KQML

based, used for the coordination of agents

C. Collaboration/CooperationAgents are collaborative when they are able to worktogether. Also the agent is able to communicate andnegotiate with the others; he is deliberative and maycoordinate his actions with the others. Collaborativeagents are useful among other things when a taskinvolves several systems on the network. Thenegotiation is the main issue of the collaborativeagents. If coordination may occur withoutcollaboration, collaboration needs negotiation.

* The mobility which is a duplication of theagent to another system (cloning).

* The agent carries his knowledge to anothersystem.

Generally mobility draws a mix of these definitions.One of the main issues of the mobility is the potentialsecurity weakness of mobile agents.

F. LearningThere is a least two definitions of learning:

* The bad one: an agent is said to learn if he isable to acquire knowledge (data).

* The good one: an agent is said to learn if he isable to use is new knowledge to modify hisbehavior.

Despite the fact that learning is an important factorof intelligence, there are only few agents able to learn;most of the time they have fixed (pre-compiled) rulesand knowledge base.

G. Pro-activeness

"Pro-active actions are intended to cause changes,rather than just reacting to change". Pro-active agentsgenerally follow plans, or at least execute rules whenthe environment reaches a known threshold.

D. Deliberation

Know rules, and apply them without waiting forinstructions. M. Wooldridge and N. Jennings define andeliberative agent as "one that contains an explicitlyrepresented, symbolic model of the world, and in whichdecisions (...) are made via logical (or at least pseudo-logical) reasoning, based on pattern matching andsymbolic manipulation"

E. MobilitySince Java had appeared, we may find a lot of mobileAgents, but there are different kinds of mobility:

* The mobility which allows the agent to movefrom one system to one similar one

* The mobility which allows the agent to moveto another different system

* The mobility which allows the agents tosuspend their action on one system, move toanother and go on.

* The mobility which allow the agent to movehimself, versus to be transported.

Sometimes pro-active is used with the same meaning asdeliberative, but an agent may be pro-active, becausehe has been requested to perform pro-active tasks, asopposed to deliberative agents, who decide themselvesto be pro-active.

H. Planning

The agent organizes by priorities the actions to performduring is life. For many researchers planning is one ofthe most important properties for an intelligent agent topossess. Planning is used by deliberative and pro-activeagents according to their knowledge of the environmentand the possible actions to apply to it.

I. Delegation

An agent may ask someone else to perform one of hisgoals or tasks. This capability is very important tomake resource balancing.

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V. PROPOSED ARCHITECTURE

Our e-learning architecture has two parts; one isclient-end and other is server-end. Both ends areconnected through internet with common sets ofinternet protocols such as HTTP, SOAP and XML(here).

Various types of computer devices are present inclient-end that can use diverse platforms. On otherhand server-side uses a single platform that mustcommunicate in this heterogeneous environment usinginternet standard-based protocols and give services in ascalable and robust manner. We have suggested a 'useragent' on client-side for customization and assistance inlearning whereas server-end consists of web servicebased intelligent agents that can also be a mobile agentfor search and discovery in other e-learning networks.Below we have broadly described our client-end andserver-end.

A. Client-End

In Figure 2, it is very clear that client-side containsdiverse computing devices and platforms. Some usermay use desktop PCs or other may use handheld andwireless devices to access learning services. We havesuggested an interface agent that works on client-side.

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swn*vOh NUser*'T n Nehse

-- - -- - -

5 -t t------------Server.End

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eduommw S.n.Io..

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This interface agent can be run on any platform andits versions 'must be different according to computingdevice hardware profiles such as its memory,processing power and storage. In this case, we havesuggested that JAVA platform is appropriate todevelop interface agent so it can be run on anycomputing device what ever its platform be. We havecategorized computing devices to make differentversions of user agent for each category. The categoryof computing devices may be a desktop PC, PDA,tablet PC and mobile phone etc.

The user agent would be configurable by user thathow frequent a user agent would contact server agent,processor usage, memory usage and networkbandwidth etc. So the user agent can give an optimizedperformance according to configurations. User agenthas also routines to handle communication betweenweb service based agents on server side, as well asgathering other relevant learning material from theweb. SOAP is used for communication between useragent and web service based agent. A user agent wouldquery information from server-side agent on the basisof user profile and device profile. User profile tellsabout user age, area of study, interest etc. whereasdevice profile tells about processing power ofcomputing device, memory, storage etc. User agentalso has animation and speech characteristics tointeract with user and maintain user attention duringlearning.

B. Server-End

The server-end of our e-learning architecture composedof several components that includes web service basedintelligent agents, database and educational services.Main focus of our architecture is on web service basedintelligent agents that can make our architecture robust,scalable and interoperable. In this paper, we areincorporating these agents with web services andexposing the main benefits of using web service basedintelligent agents. These agents can use SOAP, XMLand HTTP to communicate over a network. They candepict their functionality using WSDL just becausethese are based on web service. Clients can able to callour agents using standard based SOAP messages andtake educational services.

Database is used to store user profiles and otherrelevant data and it can be accessed through webservice. Our agents can use database to store relevantinformation about authorized users using their user

Figure 2: High-level view of e-learning architecture

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profiles when they are not online. From this point viewour intelligent agents can work in a disconnectedenvironment and serve stored information to userswhile they are online. If a user queried for someeducational service to by user agent then our intelligentagent can be mobile and move in a network to discovereducational service for user and connect it with user.Intelligent agents can track students' due dates ofassignments. They can also search relevant NEWSitems, learning objects, books, forums, courses, classes,labs etc. and track newly added services and advertiseit to respective clients and web. Not only individualclients would avail these services but other e-learningnetworks would be able accessed our intelligent agentsand educational services using SOAP.

VI. BENEFITS

By integrating web service and intelligent agenttechnologies we can achieve many benefits that cannotbe accomplished from common methods. Some of themajor benefits we found in our architecture are asbelow.

Service-Oriented: The title of the paper suggests oure-learning architecture is based on service-orientedapproach. Using web service and intelligent agenttechnology we can provide educational contents in thefonn of different services such as learning objectrepository, digital library, LMS, virtual classrooms,virtual labs, authoring services etc. you can add asmany as services by adding your web service layer.

Interoperability: You can develop web servicesusing JAVA or .NET platforms; both communicatingusing standard sets of protocols such as HTTP, XMLand SOAP. You can easily integrate your e-learningsystem with other system in this diverse web-basedenvironment.

Scalability: Our architecture provides scalableenvironment where you can grow your services easilywithout interrupting the core architecture. You can addnew educational web service and register your serviceusing UDDI or other directory service.

Flexibility: Agents are always flexible as they canmove in a network to find informnation; our web servicebased agents can communicate with other web servicesin a network using standard-based protocols such asSOAP.

Customization: A client can able to customize their'user agent' by configuring memory usage, processorusage, frequency of getting information from serveragent and many other. User profile is also plays a partin customizing user interests.

Interactivity: The main purpose of a user agent onclient-side is to provide interactivity with user. A useragent would be helpful to maintain user attentiontowards learning objectives as well as developinglearning contents.

By analyzing these benefits that are discussed aboveimplementation of this architecture for any e-learningnetwork would be beneficial. There are lots of otherbenefits that can be realized after implementing this e-learning architecture and it will obviously enhance thee-learning experience.

VII. CONCLUSION

We have proposed a service-oriented architecturefor e-learning that would greatly increaseinteroperability, scalability, maintainability, flexibility,customization and interactivity in a heterogeneous e-learning environment. Using web services andintelligent agent technology it is easy to program andmaintain services at server-end. User agents on client-side can done lot of task for user and continuouslyassist in learnig.

We are working for the implementation of ourproposed architecture to realize its full benefits andexpanding our architecture by using agent technologywith SCORM complaint learning objects.

Maintainability: Maintainability of educationalservices is easier than before because educationalservices are divided with respect to category andfunctions.

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REFERENCES

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