An Engineering Approach to Web Based Application Development

1
An Engineering Approach to Web Based Application
Development

• Cornelia Boldyreff
• Distributed Systems Engineering Group,
• RISE, University of Durham, UK
• www.dur.ac.uk/cornelia.boldyreff

2
Outline

• Web Site Development and Maintenance
• Web Metrics and Web Site Evolution
• Commercial Web-based Applications and their
  maintenance problems
• Web Processes and Quality Issues
• Web Site Engineering

3
Web Site Development and Maintenance

• Recognition of potential Web maintenance problem
  and very interesting case of software evolution
• Key paper - Measuring Readability and
  Maintainability of Hyperdocuments, Hatzimanikatis
  et al, JSM, 1995
• Possibility of working with Richard West and
  colleagues managing UK government Web sites

4
Initial Findings

• Uneven, largely poor, quality of authorship
• Badly structured documents - links not made
  systematically
• Difficulty in navigating web based documents
• Lack of tools for managing Web development and
  maintenance

5
Further Findings

• Web sites are often distributed and therefore
  maintained by several authors/maintainers
• Maintenance of Web sites uncoordinated and
  reliant on the error logs of each server,
  complaints from users, periodic checks by page
  owners
• No general consensus of opinion, or standards, on
  what constitutes a good Web page or Web site
  therefore assessment is difficult

6
Key Results

• Analysis and Assessment of Web pages and sites to
  establish quality characteristics
• Requirements Studies for Web Site Development and
  Management Support
• Workbench developed - see www.dur.ac.uk/cornelia.b
  oldyreff/workbench

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Determining Success - Web Quality Metrics

• Apply Goal-Question-Metric
• Metrics derived from Software Metrics, e.g.
  Complexity measures
• Tailored Hypertext Metrics, e.g. tree impurity
• New Web Metrics, e.g. Brays html sincerity
• Both static and dynamic measures required

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Software Evolution - Web Evolution

• Inspired by Lehman classic studies in Software
  Evolution
• Metrics here used to study changes over time
• Aim to understand and predict the web evolution
  process
• Support better, more controlled, web maintenance
  and management

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Practical Application

• Measuring and modeling the WWW allows us to study
  its structure and contents, and to determine
  quality factors operationally.
• Studying Web sites and how they change over time,
  gives us insights in web design and maintenance
  processes and their possible improvement.

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Maintenance problems associated with Commercial
Web Applications

• Large sites incorporating legacy - both systems
  and data
• Poor separation of data and code
• Generated web systems hard to maintain - lack of
  tools for periodic maintenance
• Time to launch traded off against quality
• Lack of standards awareness and usage
• Poor deployment of Database technology

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Web Management and Design Processes

• Early process models developed based on UK
  government web site management practice, and
  other more recent models derived from SE best
  practice
• Hypermedia/Web Development methods and models -
  surveyed and classified
• Metrics can be used here to guide research on
  process models for Web Site Engineering - as site
  evolves, so does process!

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Web Process Improvement and CMM

• Process models, methods, plus metrics provide the
  basis for Web Process Improvement
• Companies need guidance on how best to improve
  their existing Web development and maintenance
  practices
• Web Usability Engineering is a good starting
  point as it is key when a company is trying to
  attract and keep its Web site customers

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Improving Web Engineering Processes and Products

• Popularising the concept of web engineering -
  taking a systematic and disciplined approach to
  engineering web applications among small and
  medium enterprises - Business Informatics project
• Working with the CACDP to migrate all their
  products and services to the WWW, helping them to
  develop a well-defined engineering approach with
  reuse along classic SPI/CMM lines - emphasis on
  light weight processes
• Small projects on web site re-engineering, clone
  detection, web site re-use (web-in-a-box), web
  quality metrics
• Web-SEM project - Establishing Effective Web Site
  Evaluation metrics

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Foundations of Web Site Engineering

• Applying and adapting classical Software
  Engineering models, methods and tools to the
  engineering of web-based applications, e.g. web
  pages, web sites.
• Special case of Distributed System Engineering
• Closely related to Software Engineering but also
  recognizing important differences

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Research Taxonomy
Software Engineering
Distributed System Engineering
Software Metrics and SPI
Human-Computer Interaction
Hypermedia (Graph) Theory
Usability Metrics
Hypertext Metrics
Hyper-media Design
Web-based Software Engineering
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Establishing Web Site Engineering

• Well developed models of Web development and
  maintenance processes
• Web Software Quality Determination
• Models and Laws of Web-based Software Evolution
• Support for distributed developers - Computer
  Supported Co-operative Working applied to Web
  Site Engineering

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Key Points

• Web developers and maintainers can learn from
  Software Engineering
• Web metrics can help to characterize, to
  evaluate, and to develop new approaches to web
  engineering processes and products
• Software Engineering can provide a foundation for
  Web Engineering