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USF CS 682 - Applications and Services

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Why Web Engineering Is Needed For Web Applications and ServicesMy Basic PremisesThe Web Started Simple1st Generation2nd GenerationSome Definitions are in OrderProblems with Large Web-based ProjectsWeb Application DevelopmentWeb Application Development Current PracticesWeb Systems: ProblemsWeb Development Issues (1/2)Web Development Issues (2/2)Consideration to Quality?Web Development – Political ChallengeWeb System Development: Summary (1/2)Web System Development: Summary (2/2)3rd Generation (Multi-Tier)4th Generation?Technology DriversRange of ComplexityCharacteristicsRisks to Web-Based BusinessDesires from Web-Based BusinessNeed for ProcessOr Simply Software Engineering?Web Development vs. Software DevelopmentWeb-based Systems vs Software (1/3)Web-based Systems vs Software (2/3)Web-based Systems vs. Software (3/3)Why Engineering?Web EngineeringKey Knowledge AreasCategories of Web-based SystemsPowerPoint PresentationSlide 35Web Engineering (1/2)Web Engineering (2/2)Goals of Web EngineeringWeb Engineering Activities (1/2)Web Engineering Activities (2/2)Web Engineering is MultidisciplinaryYesterday’s Webmaster has become tomorrow’s Web EngineerSome Further ResourcesThank You Questions?Why Web Engineering Is Needed For Web Applications and ServicesBebo WhiteSLACApril 17, 2007My Basic PremisesDeveloping a Web-based system is no longer an event, it is a processWeb-based systems are growing systemsWeb-based applications are adding a whole new dimension to software developmentThe Web Started Simple“Even simple rules lead to complex behavior” – Wolfram, New Science, 2002“It is now technically possible and feasible to put the entire creative works of man online” – Kahle, The Internet ArchivesE-commerce (Web/Internet) accounted for 2% of US retail sales in 4Q, 2004 - $18.4 billion – US Census Bureau1st GenerationWeb SystemApplication protocol: HTTPBrowser / User AgentWeb ApplicationRequestResponseResourceWeb ServerWeb ApplicationClient-Side Server-SideBrowserMosaicHTMLImages (GIF)HTML-FormsHelperAudio, Video etc.Web SystemHTTPWeb ServerHTTPCGIDatabaseInformation Systems2nd GenerationWeb SystemApplication protocol: HTTPBrowser / User AgentWeb ApplicationRequestResponseResourceWeb ServerWeb ApplicationClient-Side Server-SideBrowserMosaic, NetscapeHTML, FramesImagesHTML-FormsHelperAudio, Video etc.Web SystemHTTPCookiesWeb ServerHTTPServer-API & CGIDatabaseInformation SystemsMedia ServerSome Definitions are in OrderWeb System – an infrastructure or system enabling the operation of a Web ApplicationWeb Application – a distributed application that accomplishes a certain business need based on technologies of the World Wide Web and that consists of a set of Web-specific resourcesProblems with Large Web-based Projects16-8447-5321-7937-63Satisfy Business NeedHave Required FunctionalityDelivered In TimeWithin Budget(Source: Epner, M., Cutter Consortium)Web Application DevelopmentStill Ad-hoc instead of a disciplined procedureCopy-Cut-Paste ParadigmLack between design-model and implementation-modelDesign-concepts get lost in the underlying modelMany short lifecycle of a Web Application: Maintenance and Evolution problems Reuse Problems Web Crisis(X)HTML(X)HTML(X)HTMLImplementation-ModelDesign-ModelScriptsGraphicsWeb Application DevelopmentCurrent PracticesLacks rigor, systematic approachThe completed system is not what the user wantsSystem not developed on time, cost overrunsLacks scalability and maintainability, hence a limited useful lifeDoes not meet performance requirementsResources are wastedWeb Systems: ProblemsProblemsInability to maintainUnable to meet evolving needs and grow at the rate needed – scalabilityUnreliable – crashesWeb-dependent organizations cannot afford to haveFaulty systems – reliability, security issuesFrequent downtime – dependabilityWrong, inconsistent, or stale content/informationWeb systems problems are not easy to hideWeb Development Issues (1/2)Many developers think that Web application development is just Web page creation using HTML, FrontPage, Dreamweaver, etc. with graphics design and/or simple hyperlinkingThey have been taught to think this way!Certain classes of applications do fit this simple generalization – e.g., personal Web pages, event brochures, etc.Many other Web applications go beyond simple content presentation/navigationWeb Development Issues (2/2)“There is more to Web application development than visual design and user interface”Planning, system design, testing, continual maintenance, quality assurance, performance evaluation, scalability,…Consideration to Quality?Lack of consideration to:NavigationAccessibilityScalabilityReliabilityMaintainabilityUsabilityCompatibility and interoperabilitySecurityReadabilityWeb Development – Political ChallengeAnyone can be a Web content creator and maintainer!Web SystemBusiness UnitIT DepartmentWeb Development TeamMarketingFinance/AccountingPersonnelEtc, etc(Adapted from Susan Dart, 2002)Web System Development: Summary (1/2)Less attention is given to development methodologies, testing and evaluation, quality assessment and controlLargely relies on individuals’ own development practicesLack of realization of its lifecycleAnalysis of needs, redesign, development (including coding), management, metrics, maintenanceCalls for significant system-level and design decisionsIt is an exercise – not an eventLegitimate concern about the manner in which they are created and their long-term quality and integrityWeb System Development: Summary (2/2)In many cases, Web Development is:ChaoticFailure-proneUnsatisfactory3rd Generation (Multi-Tier)Web SystemApplication protocol: HTTP, SOAP, WebDAV, otherBrowser / User AgentWeb ApplicationRequestResponseResourceWeb ServerWeb ApplicationClient-Side Server-SideUser AgentNetscape, IE, and PDA-Browser etc.Other Types of User AgentPlug-Ins, Applets, ActiveXScript-CodeDHTML, More...Web SystemHTTP, WebDAV, SOAP, otherCookiesUDDIOther relevant protocols FTP, SMTPMore...Web ServerHTTP, moreServer-API & CGIXML-SupportComponent-SupportServletsWeb-Services4th Generation?SOA FunctionalityComposition EngineFederation, SecurityTransaction, etc.SOA FunctionalityComposition EngineFederation, SecurityTransaction, etc.Configuration/ContextComponents, End


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