Web Engineering Introduction and Perspective Bibhudatta Sahoo Department of CSE NIT Rourkela

Web engineering Web engineering is way of developing and organizing knowledge about Web application development and applying that knowledge to develop Web applications, or to address new requirements or challenges. It is also a way of managing the complexity and diversity of Web applications. Web engineering is application of scientific, engineering, and management principles and disciplined and systematic approaches to the successful development, deployment and maintenance of high quality Web-based systems and applications (Murugesan et al., 1999).

Motivation The World Wide Web has become ubiquitous, and it continues to grow unabated at exponential rate Increase in depend on Web-based systems and applications, Demands for Web applications have increased significantly over the years.

Motivation Short development life-cycle times. According to our results, the average development life-cycle time is less than three months. This figure is dramatically lower than that of traditional software development. If a Web engineering process is going to be successful, then it has to cope with exceptional time pressures.

Evolution and growth of the Web The evolution of the Web has brought together some disparate disciplines such as media, information science, and information and communication technology, facilitating easy creation, maintenance, sharing, and use of different types of information from anywhere, any time, and using a variety of devices such as desktop and notebook computers, pocket PCs, personal digital assistants (PDAs), and mobile phones.

Evolution and growth of the Web Media: integration of different types of media such as data, text, graphics, images, audio and video, and their presentation ; different types of interaction and channels of communications. Information science: information organization, presentation, indexing, retrieval, aggregation, and management; and collaborative and distributed content creation. Information and communication technology and networking: efficient and cost effective storage, retrieval, processing, and presentation of information; infrastructures that facilitate transfer and sharing of data and information; wired and wireless Internet communication; and personalized and context-aware Web applications

Journey of Web Engineering 1990-1995 World Wide Web originates- 1990 Hypertext Markup Language written- 1991 Text-based browser opens WWW for use- 1992 New Web terms: HTTP and URL-1992 Graphical user interface, Mosaic, developed- 1993 HTML introduced as code for web design- 1993 World Wide Web Consortium,W3C founded- 1994 1996-2001 First Paper about Web Engineering related problems appear at the 5th WWW Conference in France-1996 Microsoft releases Explorer 3.0 Web browse- 1996 Web Engineering Homepage published WebEngineering.org -1997 First workshop on Web Engineering organized at the 7th WWW Conference in Australia- 1998 First International Conference on Web Engineering (ICWE)-2001

Journey of Web Engineering 2002-2005 For the first time Web Engineering became part of the main program-2002 First international Journal on Web Engineering published by Rinton Press, USA-2002 Web Engineering became an area of the refereed paper track at the WWW conference, demonstrating the emerging need for a discipline on development, operation, and evolution of Web applications-2003 W3C describes principles of Web architecture-2004 W3C actively busy in standardizing protocols and web technologies-2005

Anytime-Anywhere-Any media paradigm We are facing a new generation of web applications being characterized by the anytime/anywhere/anymedia paradigm, thus providing ubiquitous access to services, turning e-commerce into m-commerce.

Web based application WBA Web-based Information Systems (WIS) Web based application(WBA) defined as "any software application that depends on the Web for its correct execution" The application of systematic, disciplined and quantifiable approaches to development, operation, and maintenance of Web-based Information Systems (WIS)

A well engineered Web system is: 1/2 Functionally complete and correct Usable Robust and reliable Maintainable Secure Perform satisfactorily even under flash and peak loads Scalable Portable, where required perform across different common platforms; compatible with multiple browsers

A well engineered Web system is: 2/2 Reusable Interoperable with other Web and information systems Universal accessibility (access by people with different kinds disabilities) Well-documented

Difference [Web, Software] Engineering WBA have increased emphasis on user interface Open modularized architectures Link between business model and architecture Rapidly changing technologies More content-driven than software engineering. Increased importance of quality attributes Client uncertainty Changing business requirements Short time frames for initial delivery Fine-grained evolution and maintenance Highly competitive

Categories of Web Applications Based on functionality Category Example Informational Online newspapers, product catalogues, newsletters, manuals, reports, online classifieds, online books Interactive Registration forms, customized information presentation, online games Transactional Online shopping (ordering goods and services), online banking, online airline reservation, online payment of Bills

Categories of Web applications based on functionality Category Example Workflow oriented Online planning and scheduling, inventory management, status monitoring, supply chain Management Collaborative work environments Distributed authoring systems, collaborative design tools Online communities, marketplaces Discussion groups, recommender systems, online marketplaces, e-malls (electronic shopping malls), online auctions, intermediaries

Web Development Practices A Web development process outlines the various steps and activities of Web-based systems development. It should clearly define a set of steps that developers can follow and must be measurable and trackable. Characteristics of Web applications that make their development difficult — and uniquely challenging: For real-time interaction, complexity, changeability, the desire to provide personalized information

Characteristics of Web applications: Web applications constantly evolve. Web applications are inherently different from software. Web applications are meant to be used by a vast, variable user community ( a large number of anonymous users)

Web application development process

The objectives of context analysis Identify the stakeholders and their broader requirements and experiences. Identify the functions the Web site needs to provide (immediately, and in the short, medium, and long term). Establish what information needs to be on the Web site, how to get this information, and how often this information may change. Identify the corporate requirements in relation to look and feel, performance, security, and governance. Get a feel of the number of users (typical and peak) and anticipated demands on the system. Study similar (competitive) Web sites to gain an understanding of their functionalities, strengths, and limitations.  

Means of fulfilling the requirements of Web application Means of Fulfillment Uniform look and feel across all Web pages that can easily be modified Creation of Web pages using templates and style sheets Consistency of information that may appear in different places or pages Storing information in a single place (such as in a database or as an XML file), without duplication of information in different places or databases, and retrieving the required information for presentation where and when needed Ease of information update and maintenance Provision of a back-end system to edit information in a data repository; could have Web interface for easy access from anywhere Ability to add new Web pages easily Dynamic generation of navigational links, rather than predetermined static navigational links

Means of fulfilling the requirements of Web application Means of Fulfillment Decentralized system administration Provision of a multi-user login system to access back-end systems and inclusion of a “user administration system” that can assign specific functions and data sets to content managers and other developers/administrators Mechanisms for quality control and assessing the relevance of information Inclusion of metadata for Web pages; use of a Web robot for gathering salient information, processing the information gathered and taking appropriate action(s) for ensuring quality or relevance of information presented. Increased probability of being found through search engines Using meta tags and registering with search Engines

Web page design

Attributes of quality Web-based systems usability, navigation, accessibility, scalability, maintainability, compatibility and interoperability security and reliability

Web System Design: Challenges A flexible architecture that, facilitates greater reusability and quicker deployment. Usability — interface design, navigation Comprehension, Performance — responsiveness, Security and integrity, Evolution, growth, and maintainability, and Testability.

A well engineered web system Functionally complete and correct Usable Robust and reliable Maintainable Secure Perform satisfactorily even under flash and peak loads Scalable Portable, where required perform across different common platforms; compatible with multiple browsers Reusable Interoperable with other Web and information systems Universal accessibility (access by people with different kinds disabilities) Well-documented

How to test Web systems Browser compatibility Page display Session management Usability Content analysis Availability Backup and recovery Transactions Shopping, order processing Internalization Operational business procedures System integration Performance Login and security

Knowledge and Skills for Web Development Technologies supporting and facilitating Web applications Design methods System architecture Web development methods and processes Web project management Development tools Content management Web standards and regulatory requirements

Knowledge and Skills for Web Development [Design methods] Design for usability — interface design, navigation Design for comprehension Design for performance — responsiveness Design for security and integrity Design for evolution, growth and maintainability Design for testability Graphics and multimedia design Web page development

Web Page Design

Web engineering is specifically targeted toward the successful development, deployment and maintenance of large, complex Web-based systems.

Problems in large Web-based projects Delivered systems didn't meet business needs 84 percent of the time. Schedule delays plagued the projects 79 percent of the time. Projects exceeded the budget 63 percent of the time. Delivered systems didn't have the required functionality 53 percent of the time. Deliverables were of poor quality 52 percent of time.  

Areas that need further study Web application delivery on multiple devices Context-aware Web applications and context-sensitive responses Device-independent Web access and content presentation Modelling and simulation of Web applications and systems Performance evolution and enhancement Testing and validation of systems Effort and cost estimation Web personalization Quality control and assurance

Conclusion The essence of Web engineering is to successfully manage the diversity and complexity of Web application development, and hence, avoid potential failures that could have serious implications.

Conclusion Web Engineering is in its infancy but growing very fast. As participants in WBA development, we need to take our bearings fairly frequently and identify issues and problems, both philosophical and practical.

Reference [1] Yogesh Deshpande, Martin Gaedke "Web Engineering:Developing Successful Web Applications In ASystematic Way" 14th Intermational World Wide Web Conference, 10-14 May, 2005, Chiba, Japan. [2] R Ahmad, Z Li, F Azam "Web OPEN Integrated:Proposed Framework for Web Development",ISSN: 0302-9743, pp 533- 538, volume 3579 of Lecture Notes in Computer Science, Springer-Verlag, July 2005. [3] Gellersen, H.-W. and M. Gaedke. "Object-Oriented Web Application Development", IEEE Internet Computing 3 (1), 1999, pp. 60-68 [4] Deshpande Y, Murugesan S, Ginige A, Hansen S,Schwbe D, Gaedke M & White B "Web Engineering" Journal of Web Engineering, 1(1), 3-17, 2002 [5] Pressman, R S 'Sofiware Engineering: a Practitioner's Approach (4th ed.)',McGraw-Hill Publishing Company . [6] S. Overmyer, "What's different about requirements engineering for web sites?," Requirements Engineering Journal, vol. 5. no. 1, pp. 62-65. 2000. [7] Lowe, D., & Henderson-Sellers. B. "'Impacts on the development process of differences between web systems and conventional software systems",International Con/erence on Advances in Infrastructure for Electronic Business, Science, and Education on the Internet, L'Aquila, Italy, 2001 [8] T. Powell, D. Jones and D. Cutts: Web Site Engineering: Beyond Web Page Design. Prentice Hall,1998

Reference [10] Pressman, R S 'Can Internet-Based Applications Be Engineered?, IEEE Software, 15(5), 104-110, 1998 [11] "CERT/CC Overview" (D 1998-2003 by Camegie Mellon University [12] A.Ginige & S.Murugesan, "Web Engineering: An Introduction," IEEE MultiMedia, vol. 8, no. 1, Jan.- Mar. 2001, pp 14-18

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Reference: Emilia Mendes Associate Professor Computer Science Department The University of Auckland Private Bag 92019 Auckland, New Zealand