Journal of Computer Science 6 (3): 285-295, 2010ISSN 1549-3636© 2010 Science PublicationsCorresponding Author: Hussein K. ...
J. Computer Sci., 6 (3): 285-295, 2010286Fig. 1: A data-flow of the evolutionary modelFig. 2: The incremental development ...
J. Computer Sci., 6 (3): 285-295, 2010287System description and analysis: The system runs onMicrosoft ASP.NET 3.5 with VB....
J. Computer Sci., 6 (3): 285-295, 2010288Fig. 3: A graphical representation of the 3-tierarchitectureFig. 4: Use case diag...
J. Computer Sci., 6 (3): 285-295, 2010289Fig. 8: Sequence diagram-password generationFig. 9: Sequence diagram-storing the ...
J. Computer Sci., 6 (3): 285-295, 2010290According to new recent studies, the e-Learningstandards are of value in that the...
J. Computer Sci., 6 (3): 285-295, 2010291learning experiences that inspire and empower learners,rather than test their pat...
J. Computer Sci., 6 (3): 285-295, 2010292Fig. 15: SOA layersThe application UI can be the client program,which discovers a...
J. Computer Sci., 6 (3): 285-295, 2010293extensive list of summaries of related resources thatthey can choose to read, or ...
J. Computer Sci., 6 (3): 285-295, 2010294responsibilities and interfaces. This type of diagram isbest used during early an...
J. Computer Sci., 6 (3): 285-295, 2010295Kashfi, H. and M.R. Razzazi, 2006. A distributedservice oriented e-learning envir...
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Jurnal e-learning management system using service oriented architecture

  1. 1. Journal of Computer Science 6 (3): 285-295, 2010ISSN 1549-3636© 2010 Science PublicationsCorresponding Author: Hussein K. Al-Omari, King Abdulaziz University for Science and Technology, Riyadh, Saudi Arabia285e-Learning Management System Using Service Oriented Architecture1Mohammed A. Jabr and 2Hussein K. Al-Omari1Department of Computer Science,Amman Arab University for Graduate Studies, Amman, Jordan2King Abdulaziz University for Science and Technology, Riyadh, Saudi ArabiaAbstract: Problem statement: Service Oriented Architecture (SOA) defines how to integrate widelydisparate applications for a world that is Web based and uses multiple implementation platforms.Using (SOA) one can build durable e-learning contents, regardless of changes or evolutions intechnology. This means that new content should be added to existing content without costly redesign,reconfiguration, or recoding. Approach: In this study an e-Learning management system with Webservices oriented framework was proposed. The system will be an open source application with client-scripting facility. It also supports the cross browser and it is fully integrated with different databases;MS SQL Server, MS Access, Oracle and LDAP. Results: The key values of Interoperability,durability, compatibility, manageability, dynamic reusability and accessibility in the proposedarchitecture enhance the future e-Learning systems to communicate more efficiently and share datamore easily. Conclusion/Recommendations: Web services architecture will provide a standard basedplatform for Service-Oriented Computing. It defines itself as a set of specifications that support anopen XML-based platform for description, discovery, and interoperability of distributed,heterogeneous applications as services.Key words: eLearning, e-Learning, SCORM, evolutionary model, 3-tier architecture, service orientedarchitectureINTRODUCTIONService-based architectures take legacy applicationfunctionality and expose it to the Internet in a reliable,highly available, scalable, flexible, manageable andsecure manner, easy and reliable internet-based methodto create and access learning.Web service technology has emerged as a newparadigm of distributed computing. The Service-basedarchitectures are layered on the top of standardtransfer protocols for transmitting messages thatcurrently, the most common ones are the XML-basedspecification Simple Object Access Protocol (SOAP),Universal Description, Discovery and Integration(UDDI) and Web Service Description Language(WSDL) (Booth et al., 2003; Kashfi and Razzazi, 2006).e-Learning is a general term used to refer to a formof learning in which the instructor and student areseparated by space or time where the gap between thetwo is bridged through the use of online technologies.Many technologies can be and are, used in e-Learning, including:• Blogs and wikis• Collaborative software• Computer aided assessment• Discussion boards• Electronic performance support system• Learning management systems• Virtual classrooms• Web-based teaching materials• Web-based component servicesWhen beginning to create e-Learning content, thestudents’ profiles and courses have to be stored in thesystem database and presented using web application tofacilitate the functionality of building an e-Learningmanagement system.The proposed system is an advanced, 3-tier,database-driven using Microsoft ASP.NET 3.5 withVB.NET. The system is divided into several phases;each phase describes a number of actions. The modelused in building the system is the “EvolutionaryModel”, because it is easy to use, it allows smallsystems to be developed rapidly and it allows userengagement with the application.Evolutionary development model uses small,incremental product releases, frequent delivery to usersand dynamic plans and processes.
  2. 2. J. Computer Sci., 6 (3): 285-295, 2010286Fig. 1: A data-flow of the evolutionary modelFig. 2: The incremental development process of theelectronic learning management systemIn Fig. 1 the objective is to evolve a final systemfrom an initial outline specification starting with well-understood requirements and adding new features asproposed by the end users.In this study, the basic concept about thedevelopment process in several modules has beenpresented. Rather than deliver the system as a singledelivery, the development and delivery is broken downinto increments with each increment delivering part ofthe required functionality.Figure 2 shows the incremental developmentprocess of the Electronic Learning ManagementSystem. Early increments act as a prototype to helpelicit requirements for later increments. As shown fromthe diagram; after the system definition, thearchitectural design has been specified and then dividesthe system into small increments. The system at thattime needs to be built with these small increments andvalidated. This process will be repeated until a finalsystem has been delivered.Aims of the system: The main aims of the system are:• Improve learning accessibility that is, eliminatingbarriers to learning that many learners have foundin traditional classrooms• Improve the interaction between students andinstructors. The system has a question bank facilitywhere the students can ask questions and sendthem to their instructors• Speed up the reaching for required data andfacilitate the interaction with database records• Keep data secure. Each student has an account toauthenticate into the system• Facilitating personalized delivery of content basedon the individual learner’s knowledge and learningpreferences• Providing tracking and assessment of learners tomeasure effectiveness and compliance• Promoting knowledge sharing throughcollaborative learning• Allow students to choose what to focus on and totake control of their own learning experience(Lewis et al., 2002)• The number of articles and amount of informationthat students can access is unlimited• Providing participants with an extensive list ofsummaries of related resources that they canchoose to read, or archive for later use• Building durable e-Learning contents, regardless ofchanges or evolutions in technology. This meansthat new content should be added to existingcontent without costly redesign, reconfiguration, orrecoding• Allow students to locate and access instructionalcomponents from one remote location and deliverto other locations• The ability for a Web-based Learning ManagementSystem (LMS) to launch content that was authoredusing tools from different vendors and to exchangedata with that content• The ability to launch the same executable contentand to exchange data with that content duringexecution while utilizing Web-based LMSenvironments from different vendors• The ability for multiple Web-based LMSenvironments to access a common repository ofexecutable content and to launch such content• The ability to move an entire course from one LMSto another
  3. 3. J. Computer Sci., 6 (3): 285-295, 2010287System description and analysis: The system runs onMicrosoft ASP.NET 3.5 with VB.NET, which is afully object-oriented computer language that can beviewed as an evolution of Microsoft’s Visual Basic(VB) implemented on the Microsoft .NET framework.The system is fully integrated with differentdatabases; MS SQL Server, MS Access, Oracle andLDAP. It supports Single Sign On technology. Mostof transactions with the database are developed usingclient-scripting in order to enhance the performance ofthe system.The system is divided into three phases: Layout,database and web services. Each phase describesspecific actions taken in several locations. They aredescribed in detail below.Layout Phase: In this phase, the main concepts of theweb application design facilities in the system areintroduced. The following tools in web design are used:HTML, JavaScript, Adobe Photoshop CS, AJAXcustom extended controls and cascading style sheet.HTML, an initialize of Hypertext MarkupLanguage, is the predominant markup language forWeb pages. It provides a means to describe thestructure of text-based information in a document-bydenoting certain text as links, headings, paragraphs,lists and so on-and to supplement that text withinteractive forms, embedded images and other objects.The images in each web page will be created usingAdobe Photoshop. A variety is given to the layout ofeach web page of the system.The system is a robust, cross browser system. Theuser interface is largely the same in Microsoft InternetExplorer, Firefox and Opera. There are no menus oreditors driven by DHTML, or the like, that can fail towork in some environments.Asynchronous JavaScript And XML (AJAX) is agroup of interrelated web development techniques usedfor creating interactive web applications or rich Internetapplications. This feature has to be used in the loginprocess where the JavaScript can communicate directlywith the server, using the JavaScript XMLHttpRequestobject. With this object, the JavaScript can tradecredentials with a web server, without reloading the page.Cascading Style Sheets (CSS) is a simplemechanism for adding style (e.g., fonts, colors andspacing) to Web documents. Using CSS, the HTMLdocuments can be displayed using different outputstyles. In this system a standard CSS files has to beused to view the web pages.Database phase: This phase is connected with all othermodules. In this phase, Microsoft SQL Server 2008 hasto be used as web storage. It includes native support formanaging XML data, in addition to relational data.Web services phase: In this phase, web services areused as references in most database actions. Forexample, the data manipulation is done through webservices.All web services are web methods of functions thatperform specific actions. Web services allow the systemgreater flexibility over the Internet by allowing it towork with other systems through the Internet as if itwas a standard LAN network.It uses XML to transmit the data to and fromdifferent sources. Web services can also be consideredas connectivity tool-objects, data sets and even cachedobjects can be passed to and from other servers.System stakeholders: The main stakeholders of oursystem are:• Administrators• Instructors• Students• GuestsSystem architectural design: Various learningsystems have been developed in the past decade; themajority of these systems are implemented either withclient-server architecture or are centralized serverbased. The client-server and centralized serverapproaches are metaphors of student-teacher andrepository centric which reflect real world learningscenarios in which teachers act as the content producerswhile students act as the content consumers (Yang,2006).Our learning environment provides aninteroperable, pervasive and seamless learningarchitecture to connect, integrate and share three majordimensions of learning resources:• Learning collaborators• Learning contents• Learning servicesIn order to provide these dimensions, the three-tiersystem architecture is used.Three-tier architecture: A the 3-Tier architecture hasthe following three layers (Fig. 3).Presentation layer: In this tier the user interface has tobe built to display data to the user or accept input fromthe user. It will contain controls like text boxes,dropdown lists, gridviews and labels.
  4. 4. J. Computer Sci., 6 (3): 285-295, 2010288Fig. 3: A graphical representation of the 3-tierarchitectureFig. 4: Use case diagram-the instructor use caseBusiness Logic layer: It serves as an intermediary fordata exchange between the presentation layer and thedata access layer.Data access layer: In this layer the data is set to thedatabase back and forth. This layer only interacts withthe database. Written database queries or storedprocedures are used to access the data from thedatabase or to perform any operation to the database. Itwill get the data from the business layer and send it tothe database or get the data from the database and sendit to the business layer.Security modes: In this system there are four modes;guest, student, instructor and administrator modes.System components: The following components areprovided by the web application of the system:• Online exams• Assignments• Chat• Discussion forums• Glossary• Quizzes• Surveys• Wikis• Virtual class rooms• SCORM packager• Resources managerFig. 5: Use case diagram-the student use caseFig. 6: Use case diagram-the administrator use caseFig. 7: Sequence diagram-student data accessSystem model design: In this phase, the overall systemmodel design is explained using the necessary UMLmodels.Figure 4 describes most possible interactionsbetween the instructors and the system.Figure 5 describes most possible interactionsbetween the students and the system.Figure 6 describes most possible interactionsbetween the administrator and the system.Figure 7 describes the functionality of accessstudent pages and viewing the marks. First, the studententers username and password to access the pages andthen he views the contents of the student mode. Afterthat, he can view the marks directly.
  5. 5. J. Computer Sci., 6 (3): 285-295, 2010289Fig. 8: Sequence diagram-password generationFig. 9: Sequence diagram-storing the number of hitsFigure 8 shows the procedure of encrypting studentpassword when creating his profile by theadministrator.Figure 9 shows how a new hit is stored in thedatabase when a guest visits the system. The IPaddresses with the date of access have to be stored onlyonce a day.The administrator, instructor, or student requeststhe login page and enters the username and password.The system verifies the credentials and checkswhether the user is authorized or not. If the user isauthorized then he can access the pages, otherwise anotification will be displayed to inform that the accessis failed (Fig. 10).In Fig. 11, the web classes contain the methods andfunctions used to access the database. The webconfiguration component is used to configure thesystem functionality and to specify the applicationsettings. The web services component is used totransfer the data as xml from the database. All of thesecomponents form the web components of theapplication.Figure 12 depicts how a system is split up intological groupings and shows the dependencies amongthese groupings.Fig. 10: Activity diagram-login process of the systemFig. 11: Component diagram-system componentsFig. 12: Package diagram-system packagesMATERIALS AND METHODSToday’s e-Learning standards provide a strong newframework, creating a bridge from abstractprogrammable components to the practical world ofimplementation.
  6. 6. J. Computer Sci., 6 (3): 285-295, 2010290According to new recent studies, the e-Learningstandards are of value in that they support investmentsin:• Interoperability: That allows the Learning Objectto communicate with management systems,databases and web applications. Thiscommunication with a management system takesplace through web transport protocols (XML data,HTTP, HTTPS, or URL encoded data). Thepurpose is to exchange or update metadatainformation about the use of the Learning Object.This may involve variables, such as learner scores,preferences, completion times and progression,identifying which Learning Object to deliver next• Durability: e-Learning content should be durable,regardless of changes or evolutions in technology.This means that new content should be added toexisting content without costly redesign,reconfiguration, or recoding (Joubert, 2006)• Compatibility with major technology platforms:Such as Microsoft.NET and SUN JavaEnvironment• Manageability: Defined by enabling value to beassessed• Dynamic reusability: Using learning objects asprogrammable components. Content developersand learners should be able to extract relevant e-Learning content such as modules from differentcourses and reassemble them into a new course,application, or context (Joubert, 2006)• Accessibility: e-Learning content should be easy tofind based on the classification of the content.Users should be able to locate and accessinstructional components from one remote locationand deliver to other locations (Joubert, 2006)SCORM: The SCORM is not a standard in itself, but areference model to be used to ensure that content andmanagement systems are compatible. It stands forShared Content Objects Reference Model. The initialversion of the SCORM was centered on Web-basedlearning content and was intended to enable thefollowing:• The ability for a Web-based Learning ManagementSystem (LMS) to launch content that was authoredusing tools from different vendors and to exchangedata with that content• The ability to launch the same executable contentand to exchange data with that content duringexecution while utilizing Web-based LMSenvironments from different vendors• The ability for multiple Web-based LMSenvironments to access a common repository ofexecutable content and to launch such content• The ability to move an entire course from one LMSto anotherSCORM content must be in HTML form-viewablewithin a standard web browser. However, this does notlimit developers and designers to text or even text andimages. Multimedia and other content, such as Flash,Video, or Audio objects, can be SCORM conformant,because nearly anything that can be embedded in a webpage can be SCORM conformant. The SCORMincludes a mechanism for describing the specificrequirements of a piece of content, such as requiredplug-ins (Brown, 2002).Our learning system supports the facility ofSCORM compliant. The instructors can develop theirlearning objects using authoring tools and publish theoutput as SCORM files. Then, theses files can bedeployed into our learning system as an IMS contentpackage.Shareable Content Object Reference Model(SCORM) is a collection of standards andspecifications for the packaging and sequencing oflearning and assessment material in the form ofshareable, reusable content objects. A SCORM learningobject comprises a collection of assets, which inSCORM terminology designate pieces of instructionalor educational material. Assets within an object admitdifferent organizations, different forms of aggregationand sequencing oriented towards a definite learningpurpose (Gonzalez-Barbone and Anido-Rifon, 2008).Service Oriented Architecture (SOA): In the learningsystem, the development of dynamic contents istransformed from using normal HTML to XML. XMLprovides the answer to creating dynamic online userexperiences. Extensible Markup Language, morecommonly known as XML, has been accepted as the defacto standard for developing web applications that giveusers a much richer online experience than the simple“page turning” typical of an HTML application. Able tostore organization-relevant information in a singledatabase, XML has already become a favorite tool fordevelopers because it expresses and manages contentindependently from content delivery and managementservices.XML offers great promise that many believe willbe the final “tipping point” toward a broad-basedacceptance of e-Learning as a legitimate enterpriselearning strategy. Many believe that XML will helpestablish a new benchmark for creating dynamic online
  7. 7. J. Computer Sci., 6 (3): 285-295, 2010291learning experiences that inspire and empower learners,rather than test their patience slow-loading text andgraphical elements, page after page after page (Himesand Wagner, 2006).Service-based architectures take legacy applicationfunctionality and expose it to the Internet in a reliable,highly available, scalable, flexible, manageable andsecure manner, easy and reliable internet-based methodto create and access learning.Web service technology has emerged as a newparadigm of distributed computing. The Service-basedarchitectures are layered on the top of standardtransfer protocols for transmitting messages thatcurrently, the most common ones are the XML-basedspecification Simple Object Access Protocol (SOAP),UDDI (Universal Description, Discovery andIntegration) and Web Service Description Language(WSDL) (Booth et al., 2003; Kashfi and Razzazi,2006).The web service architecture is illustrated inFig. 13. A web service is a stand-alone softwarecomponent that has a unique URI (Uniform ResourceIdentifier).Web services architecture aims to provide astandard based platform for Service-OrientedComputing. It defines itself as a set of specificationsthat support an open XML-based platform fordescription, discovery and interoperability ofdistributed, heterogeneous applications as services(Tai et al., 2004). It is based on the interactionsbetween three roles (Ambrosi et al., 2006); serviceprovider, service registry and service requestor. Theseinteractions involve publishing, find and bindoperations and these roles and operations act upon theWeb Services artifacts.The scenario of Web services consists in fourstages as below in Fig. 14 and those stages are (Al-Ajlan and Zedan, 2007):• The service provider is deploying and publishingthe description of its services to service registryand hosting these services and controlling access tothem• The service requester works with the service brokerto discover the optimal services that meet andsatisfy the specifications of register• The service broker sends the services that havebeen found to the service requestor• The final stage, service requester negotiates withthe service providers to bind services after theyhave been foundFig. 13: Web serviceFig. 14: The scenario, roles and operations of webservicesThe typical learning management system is builtbased on a component-based architecture. However,Web services provide a better alternative as services areloosely coupled and can be subscribed anytime anyplace. Furthermore, leveraging web standards in an e-Learning environment will allow the dynamicintegration of applications distributed over the web andencourage reuse of learning objects (Fang and Sing,2009).The typical learning management system is builtbased on a component-based architecture. However,Web services provide a better alternative as services areloosely coupled and can be subscribed anytime anyplace. Furthermore, leveraging web standards in an e-Learning environment will allow the dynamicintegration of applications distributed over the web andencourage reuse of learning objects (Fang and Sing,2009).Service Oriented Architecture (SOA) layers: Asshown in Fig. 15, the application UI layer represents thepresentation layer for the clients. This layer is describedas a presentation tier in the 3-tier architecture. In thistier the user interface has to be built to display data tothe user or accept input from the user. It will containcontrols like text boxes, dropdown lists, gridviews andlabels.
  8. 8. J. Computer Sci., 6 (3): 285-295, 2010292Fig. 15: SOA layersThe application UI can be the client program,which discovers and invokes the business processes orservices from the service registry. The services beinginvoked can be a single service or a composite servicedepending on the user learning goals.As users vary according to ability, prerequisiteknowledge, learning pace and learning objectives, it isideal to provide customized e-Learning services tothem. The services, which are published to the serviceregistry can be discovered and invoked through theinterface- Web Service Description Language (WSDL).The service registry is the dynamic components librarythat will contain all services in our system.RESULTSThe fully object-oriented language used in theimplementation of the system improves the ability todeploy several web services.Web services provide a better alternative asservices are loosely coupled and can be subscribedanytime any place. Furthermore, leveraging webstandards in an e-Learning environment will facilitatethe dynamic integration of systems distributed over theweb and encourage reuse of learning objects.In the learning system, the development ofdynamic contents is transformed from using normalHTML to XML. XML provides the answer to creatingdynamic online user experiences. Extensible MarkupLanguage, more commonly known as XML, has beenaccepted as the de facto standard for developing webapplications that give users a much richer onlineexperience than the simple “page turning” typical of anHTML application. Able to store organization-relevantinformation in a single database, XML has alreadybecome a favorite tool for developers because itexpresses and manages content independently fromcontent delivery and management services.Using SCORM standard in our system provides uswith:• The ability for a Web-based Learning ManagementSystem (LMS) to launch content that was authoredusing tools from different vendors and to exchangedata with that content• The ability to launch the same executable contentand to exchange data with that content duringexecution while utilizing Web-based LMSenvironments from different vendors• The ability for multiple Web-based LMSenvironments to access a common repository ofexecutable content and to launch such content• The ability to move an entire course from one LMSto anotherThe proposed framework using the Web Serviceapproach will increase the efficiency and effectivenessof collaborative learning in terms of e-Learningstandards; reusability, interoperability, accessibility,and modularization.DISCUSSIONThe development of e-Learning ManagementSystem can be accomplished with respect toevolutionary model. Also, using UML modeling willmake the implementation and deployment of the systemeasy. The output exported from the contents of thesystem will be compatible with other learningmanagement systems as the SCORM standards is used.In order to facilitate the interaction between thedatabase and the business logic in development, ascripting language such as AJAX is used. The fullyobject-oriented classes are used in our system to containthe methods and functions used to access the database.The web configuration component is used to configurethe system functionality and to specify the applicationsettings. The web services component is used totransfer the data as xml from the database. All of thesecomponents form the web components of theapplication.CONCLUSIONAs can be seen from reading this study, by usingour learning management system facilities, thegeographical barriers are eliminated, opening upbroader administration and education options. Thesystem can facilitate personalized delivery of contentsbased on the individual learner’s knowledge andlearning preferences. It will provide participants with an
  9. 9. J. Computer Sci., 6 (3): 285-295, 2010293extensive list of summaries of related resources thatthey can choose to read, or archive for later use. Amiddleware for uniform access to all thesis resourcesthat belong to different administration areas isproposed. New technologies are described, includingweb services, single sign on and AJAX and how theycan be used in the development of our system.In this study, a 3-tier architectural e-Learningsystem is defined. The objective of this architecture isto supply a basis for designers, developers andinstructors to construct practicable strategic e-Learningmodels suitable for their individual e-Learningenvironments.The proposed framework using the Web Serviceapproach will increase the efficiency and effectivenessof collaborative learning in terms of Reusability,Interoperability, Accessibility and Modularization(Fang and Sing, 2009).Glossary:Activity: An activity represents the performance of taskor duty in a workflow. It may also represent theexecution of a statement in a procedure. An activity issimilar to a state, but expresses the intent that there is nosignificant waiting (for events) in an activity. Transitionsconnect activities with other model elements and objectflows connect activities with objects.Business process or business method: Is a collectionof related, structured activities or tasks that produce aspecific service or product for a particular customer orcustomers. It often can be visualized with a flowchart asa sequence of activitiesClass diagram: It shows the existence of classes andtheir relationships in the logical design of a system. Aclass diagram may represent all or part of the classstructure of a system.Deployment model: Type of UML diagrams, depictthe physical resources in a system including nodes,components and connections.e-Learning (or electronic learning or eLearning):Encompasses forms of Technology-Enhanced Learning(TEL) or very specific types of TEL such as online orWeb-based learning.IMS: Stands for instructional management systems,now commonly mentioned as the IMS global learningconsortium is a non-profit standards organizationconcerned with establishing interoperability forlearning systems and learning content and the enterpriseintegration of these capabilities.Learning design: is a specification for a metalanguagethat enables the modeling of learning processes. Thespecification is maintained by IMS global learningconsortium. Learning design has the potential torevolutionize e-Learning by capturing the “process” ofeducation, rather than simply content. By describingsequences of collaborative learning activities, learningdesign offers a new approach to re-use in e-Learning(Dalziel, 2003).LMS: A program used to put course information on theweb is usually called a learning management system.Incremental development model: Increment modeldelivers software in small pieces called increments,each increment build on those that have been alreadydelivered. System is developed and delivered inincrements after establishing an overall architecture.Open source: Is an approach to the design,development and distribution of software, offeringpractical accessibility to software’s source code.Package diagram: Is a type of diagram in the UnifiedModeling Language that depicts how a system is splitup into logical groupings and shows the dependenciesamong these groupings. As a package is typicallythought of as a directory they make for a good logicalhierarchical decomposition of the system.Pedagogy: Pedagogy is also sometimes referred to asthe correct use of teaching strategies.Risk: A risk is a probability that some adverse(unfavorable) circumstance will occur.Scalability: It is a desirable property of a system, anetwork or a process, which indicates its ability toeither handle growing amounts of work in a gracefulmanner, or to be readily enlarged.Security: It is the condition of being protected againstdanger or loss. In the general sense, security is aconcept similar to safety.Sequence diagram: It is a graphical view of a scenariothat shows object interaction in a time-basedsequence¾what happens first, what happens next.Sequence diagrams establish the roles of objects andhelp provide essential information to determine class
  10. 10. J. Computer Sci., 6 (3): 285-295, 2010294responsibilities and interfaces. This type of diagram isbest used during early analysis phases in design becausethey are simple and easy to comprehend. Sequencediagrams are normally associated with use cases.Sharable Content Object Reference Model(SCORM): Is a collection of standards andspecifications for web-based e-Learning. It definescommunications between client side content and a hostsystem called the run-time environment. SCORM alsodefines how content may be packaged into atransferable ZIP file.Systems analysis: It is the science dealing withanalysis of complex, large-scale systems and theinteractions within those systems.UML: Unified Modeling Language.Use case: In its simplest form, a use case can bedescribed as a specific way of using the system from auser’s (actor’s) perspective.Web Service Description Language (WSDL): Is anXML format for describing network services as a set ofendpoints operating on messages containing eitherdocument-oriented or procedure-oriented information.The operations and messages are described abstractlyand then bound to a concrete network protocol andmessage format to define an endpoint. Related concreteendpoints are combined into abstract endpoints(services). WSDL is extensible to allow description ofendpoints and their messages regardless of whatmessage formats or network protocols are used tocommunicate, however, the only bindings described inthis document describe how to use WSDL inconjunction with SOAP 1.1, HTTP GET/POST andMIME (Christensen et al., 2001).Web server: A computer that is responsible foraccepting HTTP requests from clients, which areknown as Web browsers and serving them HTTPresponses along with optional data contents, whichusually are Web pages such as HTML documents andlinked objects.Web services: Are objects and methods that can beinvoked from any client over HTTP. Web Services arebuilt on the Simple Object Access Protocol (SOAP).Unlike the Distributed Component Object Model(DCOM) and Common Object Request BrokerArchitecture (CORBA), SOAP enables messaging overHTTP on port 80 (for most Web servers) and uses astandard means of describing data. SOAP makes itpossible to send data and structure easily over the Web.REFERENCESAl-Ajlan, A. and H. Zedan, 2007. E-learning(MOODLE) based on service oriented architecture.Proceeding of the EADTU’s 20th AnniversaryConference, Nov. 8-9, Lisbon-Portugal, pp: 62-70.Ambrosi, E., M. Bianchi, and G. Felici, 2006. When isit convenient to predict the web servicescompletion time? Proceedings of the 24th IASTEDInternational Conference on Parallel andDistributed Computing and Networks, Feb. 14-16,ACTA Press Anaheim, CA., USA., pp: 250-255.Booth, D., H. Haas, F. McCabe, E. Newcomer, and M.Champion et al., 2003, Web services architecture.World-Wide-Web Consortium (W3C).http://www.w3.org/TR/ws-arch/Brown, J., 2002. Making a macromedia flash MXlearning object SCORM-conformant.http://www.adobe.com/resources/elearning/whitepapers.htmlChristensen, E., F. Curbera, G. Meredith, and S.Weerawarana, 2001. Web Services DescriptionLanguage (WSDL) 1.1.http://www.w3.org/TR/wsdlDalziel, J., 2003. Implementing learning design: TheLearning Activity Management System (LAMS).Proceedings of the 20th Annual Conference of theAustralasian Society for Computers in Learning inTertiary Education, Dec. 7-10, Adelaide, Australia,pp: 593-596.http://www.ascilite.org.au/conferences/adelaide03/docs/pdf/593.pdfFang, C.F. and L.C. Sing, 2009. Collaborative learningusing service-oriented architecture: A frameworkdesign. Knowl. Based Syst., 22: 271-274. DOI:10.1016/j.knosys.2009.01.003Gonzalez-Barbone, V. and L. Anido-Rifon, 2008.Creating the first SCORM object. Comput. Educ.,51: 1634-1647. DOI:10.1016/j.compedu.2008.04.004Himes, F. and E.D. Wagner, 2006. Macromedia MX:Empowering Enterprise eLearning. San FranciscoCA: Macromedia, Inc.http://download.macromedia.com/pub/solutions/downloads/elearning/empower_enterprise.pdfJoubert, Q., 2006. SCORM: The basics.http://www.cybermediacreations.com/2006/12/scorm-basics.html
  11. 11. J. Computer Sci., 6 (3): 285-295, 2010295Kashfi, H. and M.R. Razzazi, 2006. A distributedservice oriented e-learning environment based ongrid technology. Proceeding of the Saudi 18thNational Computer Conference (NCC’06), Saudi,pp: 1-1.http://colleges.ksu.edu.sa/ComputerSciences/Pages/default.aspxLewis, B., V. MacEntee, and P. Youngs-Maher, 2002.Software compare and contrast: Blackboard-WebCT and lotus notes dominos a paneldiscussion. Proceeding of the IS2002, InformingScience + IT Education Conference, June 2002,pp: 919-931.http://informingscience.org/proceedings/IS2002Proceedings/papers/lewis167softw.pdfTai, S., R. Khalaf, and T. Mikalsen, 2004. Compositionof coordinated web services. Proceeding of the 5thACM/IFIP/USENIX International Conference onMiddleware, Oct. 18-22, ACM Press, Toronto,Canada, pp: 294-310.http://portal.acm.org/citation.cfm?id=1045658.1045680Yang, S.J.H., 2006. Context aware ubiquitous learningenvironments for peer-to-peer collaborativelearning. Educ. Technol. Soc., 9: 188-182.

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