1. Software Engineering Project Management
BS(Information Technology) P-IV
LECTURE#4
COURSE TEACHER
SURHAN HAMEED MEMON
Institute of Information Technology
Mohtarma Benzair bhutto Shaheed Campus Dadu University of sindh

2. Introduction to Web Engineering

3. 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 development

4. The 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, $18.4 billion – US Census Bureau

5. Introduction The World Wide Web was invented by English scientist
 Tim Berners-Lee in 1989.
He wrote the first web browser in 1990 while employed  in Switzerland.
The concept of web engineering was developed in the middle 1990s when web development practitioners and researchers eventually realized web development is beyond just web page design and systematical process is needed to develop large scale web sites.

6. What is Web Engineering?
“Web Engineering is concerned with establishment and use of sound scientific, engineering and management principles and disciplined and systematic approaches to the successful development and maintenance of high quality Web-based systems and applications”

7. Web Engineering
Web Engineering is a discipline among disciplines, cutting across computer science, information systems, and software engineering, as well as benefiting from several non-IT specializations.
“While Web Engineering adopts and encompasses many software engineering principles, it incorporates many new approaches, methodologies, tools, techniques, and guidelines to meet the unique requirements of Web-based systems.
Developing Web-based systems is significantly different from traditional software development and poses many additional challenges”

8. Web Engineering
The application of systematic, disciplined, and quantifiable
approaches to the design, production, deployment,
operation, maintenance and evolution of Web-based
software products.

9. Web Engineering (1/2)
A holistic and proactive approach to Web systems development
Offers systematic approaches and disciplined processes for development
Deals with the management of complexity and diversity of Web development
Brings to Web-based system development
Control
Risk minimization
Enhanced maintainability and quality

10. Web Engineering (2/2) Other factors Changing technology
Budget and time constraints
Division between theory and practice
Lack of understanding

11. Problems with Large Web-based Projects

12. What About Complex Web Systems?

13. Range of Complexity Dynamically Created Web Application Site
Service-Based
Web Application
and Federations
Complex
Dynamically Created
Site
Web Application
Dynamic Data Access
Service
Static
Site
Data
Collector Site
Simple
Document Centered
Application Centered

14. 4th Generation of Web Systems?
Classification
Web Services Universe
Discovery
IP/STS
P/LS
Cluster:
Presence / Location Server
Identification Provider / Security Token Service
HTTP/SOAP
Security
Context
Presence/Location
Context
Communication
SOA Functionality
Composition Engine
Federation, Security
Transaction, etc.
Configuration/Context
Components, End Points
Semantic Web
Policy, Permissions, etc.
Model-driven support systems

15. Web Application Development
Still Ad-Hoc instead of a disciplined procedure
Copy-and-Paste Paradigm
Lack between Design Model and Implementation Model
Design concepts get lost in the underlying model
Short lifecycle of a Web Application -> Maintenance and Evolution issues -> Reuse issues

16. Web Application Development Current 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 limited useful life
Does not meet performance requirements
Resources are wasted

17. Web 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 hide

18. Web Development Issues
Many developers think that Web application development is just accomplished using “off the shelf” tools
They have been taught to think this way
Certain classes of applications do fit this simple generalization
Many other Web applications do not
“There is more to Web application development than visual design and user interface”
Planning, system design, testing, continual maintenance, quality assurance, performance evaluation, scalability,….

19. Consideration to Quality?
Lack of consideration to:
Accessibility
Scalability
Reliability
Maintainability
Usability
Security
Readability

20. Accessibility
Accessibility refers to the inclusive practice of removing barriers that prevent interaction with, or access to websites by people with disability.
Currently most Web sites and Web software have accessibility barriers that make it difficult or impossible for many people with disabilities to use the Web.
As more accessible Web sites and software become available, people with disabilities are able to use and contribute to the Web more effectively.
 When sites are correctly designed, developed and edited, all users have equal access to information and functionality.

21. Scalability
Scalability is the trait where a software solution can handle increased loads of work. This can be larger data-sets, higher request rates, combination of size and velocity etc.
It is the ability of a computer application or product (hardware or software) to continue to function well when it (or its context) is changed in size or volume in order to meet a user need.
Typically, the rescaling is to a larger size or volume.

22. Reliability
Reliability is the ability of a system to perform its required functions under stated conditions for a specific period of time.
Constraints on the run-time behavior of the system Can be considered under two separate headings.
Availability
Failure Rate

23. Availability And Failure Rate
Availability is the system available for service when requested by end-users.
Failure rate –
Failure ate s how often does the system fail to deliver the service as expected by end-users.

24. Maintainability
Maintainability is the ease with which a product can be maintained in order to:
Isolate defects or their cause,
Repair or replace faulty or worn-out components without having to replace still working parts,
Prevent unexpected breakdowns,
Maximize a product's useful life,
Maximize efficiency, reliability, and safety,
Meet new requirements
Make future maintenance easier, or
In some cases, maintainability involves a system of continuous improvement- learning from the past in order to improve the ability to maintain systems based on maintenance experience.

25. Usability
Usability requirements include: ‹Well-structured user manuals ‹Informative error messages ‹Help facilities ‹Well- formed graphical user interfaces

26. Security
Security requirements are included in a system to ensure the unauthorized access to the system and its data is not allowed ‹ Ensure the integrity of the system from accidental or malicious damage

27. Readability
Readability is the ease with which a reader can understand a written text.
The readability of a particular text depends on content.
Readability is different from legibility which is a measure of how easily a reader can distinguish individual letters or characters from each other.
Readability can determine the ease with which humans can read computer program code, such as in embedded documentation.
Easy reading helps learning and enjoyment, so what we write should be easy to understand.

28. Web Development – Political Challenge
Anyone can be a Web content creator and maintainer!

29. Risks to Web-Based Business
Long system delivery time
Low responsiveness to business changes
High project development and ongoing support costs
Questionable system quality

30. Web Engineering is Multidisciplinary

31. Desires of Web-Based Businesses
Project delivery time – shorter
System quality – improved
Technology investment - optimized

32. Thank You