Lect 1 (Introduction to Web Engineering).pptx
- 1. Introduction to Web Engineering 1 1
- 2. Outline Introduction to the Course What is web engineering? Web applications The case for web engineering Categories of web applications Characteristics of web applications 2
- 3. 1. Introduction to the Course This course aims: to introduce the methods and techniques used in Web-based application development to develop practical web applications 3
- 4. 1.1 Web engineering methods and techniques This modules includes the following topics: Product development Requirement engineering Web application modeling Web application architectures Technologies and tools Testing web applications Maintenance Quality Aspects: Security 4
- 5. 1.2 Web application development Server sends requested files to browser to be interpreted User receives file displayed by the browser 5 Browser interprets user’s selection and makes request from appropriate server Server accepts and processes request from browser User sends request Browse r 5
- 6. 1.2 Web application development… • Hyper-text Markup Language (HTML) • Cascading Style-sheets (CSS) • Client-side Scripting Language (JavaScript) • Serve-side Scripting Language (PHP) • Database Language (MySQL) 6
- 7. 2. Web engineering • Software engineering is an engineering discipline that is concerned with all aspects of software production • Software Engineering is the science and art of building significant software systems that are: on time on budget with acceptable performance with correct operation 7
- 8. 2. Web engineering… Web engineering is the study of the process, used to create high quality Web-based applications Web engineering draws heavily on the principles and management activities found in software engineering processes Web engineering extends Software Engineering to Web applications 8
- 9. 2. Web engineering… The application of systematic and quantifiable approaches to cost-effective analysis, design, implementation, testing, operation, and maintenance of high-quality web applications 9
- 10. 3. Web applications WWW has massive and permanent influence on our lives Economy, Industry, education, healthcare, entertainment Why? global and permanent Comfortable and uniform access 10
- 11. 3. Web applications… WWW started as an informational medium Evolved into application medium Interactive, data intensive services Distinguishing factors How it is used? Technologies and standards for development 11
- 12. 3. Web applications… A Web application is a system that utilizes W3C standards & technologies to deliver web-specific resources to clients (typically) through a browser Technology + interaction 12
- 13. 4.The case for web engineering 14 Application development on the Web remains largely ad hoc unplanned, one-time events Individual experience Little or no documentation for code/design Short-term savings lead to long-term problems in operation, maintenance, usability, etc. lack of performance, reliability, user-freindliness and scalability Because Web apps are so interdependent, the problem is compounded 13
- 14. 4.The case for web engineering… Root Causes of poor design: Development as an authoring activity Development is “easy” Techniques that should not be used are misapplied Techniques that should be used are not applied 14
- 15. 4.The case for web engineering… Top project drawbacks (Cutter, 2000) 84% - Failure to meet business objectives 79% - Project schedule delays 63% - Budget overrun 53% - Lack of functionality Web Engineering’s solution: Clearly defined goals & objectives Systematic, phased development Careful planning Iterative & continuous auditing of the entire process 15
- 16. 5. Categories of web applications Document-centric web Interactive and transactional web applications Workflow-based web applications Collaborative and social web applications Portal-oriented web applications Ubiquitous web applications 16
- 17. 5.1 Document-centric web sites originator to Web applications Static HTML documents Manual updates Pros Simple, stable, short response times Cons High management costs for frequent updates & large collections More prone to inconsistent/redundant info Example: static home pages 17
- 18. 5.2 Interactive & transactional Not only read-only content but also allow content modification Come with the introduction of HTML forms Simple interactivity Dynamic page creation Web pages and links to other pages generated dynamically based on user input 18
- 19. 5.2 Interactive & transactional… Content updates -> Transactions Database connectivity Increased complexity Examples: news sites, booking systems, online banking 19
- 20. 5.3 Workflow-based applications Designed to handle business processes across departments, organizations and enterprises Automates processes consisting of series of steps Business logic defines the structure High complexity; autonomous entities Examples: B2B and e-Government 20
- 21. 5.4 Collaborative & social web Unstructured, cooperative environments Support shared information workspaces to create, edit and manage shared information Interpersonal communication is paramount Classic example: Wikis The Social Web Moving towards communities of interest Examples: Blogs, facebook, twitter etc. 21
- 22. 5.5 Web portals 23 One specially-designed at a website which brings information together from diverse sources in a uniform way Each information source gets its dedicated area Specialized portals Business portals Marketplace portals Community portals 22
- 23. 5.6 Ubiquitous web applications Customized services delivered anywhere via multiple devices Still an emerging field 23
- 24. 5.7 Categories of Web Applications (development history vs complexity) Social Web Collaborative Ubiquitous Workflow Based Transactional Portal Oriented 24 Interactive Doc-Centric oDvt.eCvolleegleopment Complexity
- 25. 6. Characteristics of Web Applications How do Web applications differ from traditional applications? 3 dimensions Product-based Usage-based Development-based 26 25
- 26. 6.1 Product-based characteristics 27 Product-related characteristics constitute the “building blocks” of a Web application Content: Document character & multimedia Quality demands: current, exact, consistent, reliable 26
- 27. 6.1 Product-based characteristics… Navigation Structure (Hypertext): Non-linearity Potential problems: Disorientation & cognitive overload User interface (Presentation): Appearance Self-explanation 27
- 28. 6.2 Usage-based characteristics Much greater diversity compared to traditional non- Web applications Users vary in numbers, cultural background, devices, h/w, s/w, location etc Social Context (Users): Spontaneity - scalability Heterogeneous groups 28
- 29. 6.2 Usage-based characteristics… Technical Context (Network & Devices) Quality-of-Service Natural Context (Place & Time): Globality Availability 29
- 30. 6.3 Development-based characteristics The Development Team: Multidisciplinary – print publishing, s/w development, marketing & computing, art & technology Technical Infrastructure: Lack of control on the client side 30
- 31. 6.3 Development-based characteristics Integration: Internal: with existing legacy systems External: with Web services Integration issues: correct interaction, guaranteed QoS 31
- 32. Summary Web engineering extends Software Engineering to Web applications Why web engineering? Web applications Categories and characteristics of web applications 32
Editor's Notes
- #12: The World Wide Web Consortium (W3C) is an international public-interest non-profit organization where Member organizations, a full-time staff, and the public work together to develop Web standards.
- #13: Scalability refers to the ability of a system to handle increasing or decreasing demand without compromising quality or efficiency. Reliability refers to the ability of a system to maintain its functionality and service level despite faults, errors, or disruptions.
- #14: the process of writing an electronic document or software program, mostly a hypertext or multimedia application.
- #15: Auditing for compliance to requirements
- #16: Ubiquitous web applications: These applications involve identifying resources and managing them within the context of an application session.
- #20: An autonomous country, organization, or group governs or controls itself rather than being controlled by anyone else.
- #21: Paramount: important, major goal. Interpersonal communication refers to communication between two or more people. It involves the exchange of messages, ideas, and information between individuals.
- #23: These applications involve identifying resources and managing them within the context of an application session. The resources can be remote as in a network printer and projector, or local, as in the estimated battery life, network signal strength, and audio volume level.
- #27: Nonlinearity is a property of mathematical functions or data that cannot be graphed on straight lines, systems whose output(s) are not directly proportional to their input(s). Useless things are added in the system, that overload the performance of system. Even the most intelligent person can only process so much information at once.
- #28: Scalability is the measure of a system's ability to increase or decrease in performance and cost in response to changes in application and system processing demands.
- #29: Quality of service (QoS) is a set of technologies that work on a network to guarantee its ability to dependably run high-priority applications and traffic under limited network capacity.
- #31: Separate part working altogether. A legacy system is any outdated computing system, hardware or software that is still in use. Legacy systems include computer hardware, software applications, file formats and programming languages. However, not all legacy systems are obsolete technologies.