An Introduction to Web Engineering

1
An Introduction to Web Engineering

• Jumana Ali Hbahbeh 20050171035
• Mohammad Al-Masri 20050171021
• Dr.Natheer Khasawneh
• Eng.Ahmad Shatnawi

2
Head Lines

• Introduction.
• Motivation
• Categories of Web Application.
• Characteristics of Web Application
• Product - related Characteristic.
• Usage related Characteristic.
• Development related Characteristic.
• Evolution.
• 4. Questions !

3
Introduction

• Web Engineering comprises the use of
  systematic and quantifiable approaches in order
  to accomplish the specification, implementation,
  operation, and maintenance of high quality Web
  applications.

4
Why Web Applications?

• The World Wide Web has a massive and permanent
  influence on our lives(education,
  healthcare.etc) and this is because of the
  nature of the Web itself.
• While originally the Web was designed as a purely
  informational medium, it is now increasingly
  evolving into an application medium.
• Web applications today are full-?edged, complex
  software systems providing interactive, data
  intensive, and customizable services accessible
  through different devices.

5
Nature of the Web

• global and permanent availability.
• Comfortable.
• uniform access to often widely distributed
  information producible by anyone in the form of
  Web pages.

6
What is the WA?

• A Web application is a software system based on
  technologies and standards of the World Wide Web
  Consortium (W3C) that provides Web specific
  resources such as content and services through a
  user interface, the Web browser.
• So the main components of the WA are
• Software(tech.), user interface, the web
  itself.

7
How WAs are developed now?

• The development of Web applications is often seen
  as a one-time event.
• it is often spontaneous.
• usually based on the knowledge, experiences, and
  development practices of individual developers.
• limited to reuse in the sense of the Copy
  Paste paradigm.
• ultimately characterized by inadequate
  documentation of design decisions.

8
What are the problems with this way of developing
WAs?

• Massive quality problems and consequently in
  great problems in operation and maintenance.
• Applications developed are often heavily
  technology dependent and error-prone.
• characterized by a lack of performance,
  reliability, and scalability, user-friendliness,
  and therefore also acceptance.
• The strong interlinking of Web applications
• additionally increases the danger of problems
  spreading from one application to the other.

9
What are the reasons for these problems?

• Document-centric approach.
• The development of Web applications is often
  still considered to be document centric.
• The assumed simplicity of Web applications
  development. two main reasons
• The broad availability of different tools editors
  or form generators(dont need specialized
  knowledge).
• emphasis is on visual design rather than internal
  structuring and programming. This results in
  inconsistencies and redundancy.
• Know-how from relevant disciplines cannot be
  applied or is not used.

10
Are there Differences between the WA and the
traditional software ?

• It is a common misconception that the development
  of Web applications is analogous to the
  development of traditional applications.
• And there is also a misconception that the
  methods of Software Engineering can be used in
  the sense of a systematic, disciplined approach
  with adequate quality control measures.
• This appears inadequate in many cases due to the
  special characteristics of Web applications.
• Development standards for high-quality Web
  applications are nonexistent this is in part
  due to the relatively short history of the Web.

11
Web Crisis

• A survey by the Cutter Consortium (Cutter
  Consortium 2000) found that the top problem areas
  of large-scale WA projects were
• he failure to meet business needs (84)
• Project schedule delays (79)
• budget overrun (63)
• lack of functionality (53)
• poor quality of deliverables (52)
• Due to the omnipresence of WAs and their strong
  cross-dependency, this Web crisis could be
  considerably more serious and widespread than the
  software crisis of the 1960s.

12
Web Application Engineering

• What is Engineering?
• What is Software Engineering?
• And so, What is the WAE?

13
Web Application Engineering

• Engineering means the practical application of
  science to commerce or industry with the goal of
  designing applications in a better, i.e. faster /
  cheaper / more secure / etc.
• SE is an engineering discipline that is concerned
  with all aspects of software production from the
  early stages of system specification to
  maintaining the system.

14
Web Application Engineering

• Web Engineering is the application of systematic
  and quantifiable approaches (concepts, methods,
  techniques, tools) to cost-effective requirements
  analysis, design, implementation, testing,
  operation, and maintenance of high-quality Web
  applications.
• Web Engineering is also the scientific discipline
  concerned with the study of these approaches.

15
Categories of WAs

• We will identify the WAs depending on their
  development history and complexity.

16
Categories of WAs

• Document centric Web sites, the precursor to Web
  applications, static, HTML, benefits are the
  simplicity and stability of such Web sites and
  the short response time.
• interactive Web applications, CGI and HTML forms,
  Ex. news sites, or timetable information.
• Transactional Web applications, gives the user
  the possibility of not only interacting with the
  application in a read-only manner, but also by
  performing updates on the underlying content,
  there must be a data base system, EX. Online
  banking, online shopping, and booking

17
Categories of WAs

• 4. Work?ow-based Web applications, handling of
  work?ows within or between different companies,
  public authorities, and private users, use Web
  services to guarantee interoperability, EX. B2B
  solutions in e-commerce.
• 5. Collaborative Web applications, cooperation
• purposes in unstructured operations (groupware),
  While originally the Web was characterized by
  anonymity, there is an increasing trend towards a
  social Web, EX. Weblogs.

18
Categories of WAs

• 6. Portal-oriented Web applications, provide a
  single point of access to separate, potentially
• heterogeneous sources of information and
  services, there are various specialized portals
  such as business portals, marketplace portals.
• 7. Ubiquitous Web applications, provides
  customized services anytime anywhere and for any
  device, thus facilitating ubiquitous access. Ex.
  Using mobile devices and location-aware services.
• 8. Semantic Web present information on the Web
  not merely for humans, but also in a machine
  readable form, This would facilitate knowledge
  management on the Web and increase the
  possibility to automating tasks.

19
Characteristics of Web Applications

• WA characteristics fall within three dimensions
• Product
• Usage
• Development
• Along with their ? Evolution

20
Characteristics of Web Applications

• Product-related Characteristics
• a. Content
• Generating content, making it available,
  integrating, and updating.
• Web application developers must therefore not
  only act as programmers but also as authors.
• Depending on the structuring, content is provided
  as tables, text, graphics, animations, audio, or
  video.
• Content is in part also generated and updated
  dynamically.
• Web application is not only subject to differing
  update frequencies, but also to different quality
  metrics regarding its being up to date, exact,
  consistent and reliable.

21
Characteristics of Web Applications

• 1. Product-related Characteristics
• b. Hypertext
• The hypertext paradigm as a basis for the
  structuring and presentation of information.
• Basic elements of hypertext models are nodes,
  links and anchors.
• Non-linearity Hypertexts imply stereotypes of
  relatively systematic reading, We can distinguish
  among others between browsing, e.g. in online
  shopping applications, queries, e.g. in virtual
  exhibitions, and guided tours, e.g. in e-learning
  applications.

22
Characteristics of Web Applications

• Problems
• Disorientation is the tendency to lose ones
  bearings in a non-linear document.
• Cognitive overload is caused by the additional
  concentration required to keep in mind several
  paths or tasks simultaneously.
• Solutions
• Sitemaps, key word searches, Meaningful linking
  and intelligent link naming reduce cognitive
  overload and disorientation.

23
Characteristics of Web Applications

• Product-related Characteristics
• c. Presentation
• Aesthetics, look and feel of the user interface
  plus the high competitive pressure on the Web.
• Self-explanation, it should be possible to use
  aWeb application without documentation.

24
Characteristics of Web Applications

• 2. Usage-related Characteristics
• The usage of Web applications is extremely
  heterogeneous. Users vary in numbers and cultural
  background, devices have differing hardware and
  software characteristics.
• And the time and location from where the
  application is accessed cannot be predicted.
• Usage has three main contexts social context,
  technical context, and natural context.

25
Characteristics of Web Applications

• 2. Usage-related Characteristics
• a. Social Context ? Users
• Spontaneity
• Multi- culturality
• b. Technical Context ? Network and Devices
• Quality of service, The characteristics of the
  transmission medium, such as bandwidth,
  reliability, and varying stability of the
  connection are independent factors that must be
  considered when developing a Web application to
  guarantee appropriate quality of service.
• Multi-platform delivery, Web applications usually
  offer services not only to a speci?c type of
  device, but rather any, such as different mobile
  types, different browsers

26
Characteristics of Web Applications

• 2. Usage-related Characteristics
• c. Natural Context ? Location and Time
• Globality, The location from which a Web
  application is accessed, is important for the
  internationalization.
• Global availability also increases the demands on
  security of Web applications to prevent users
  from accessing deliberately or by accident
  private or con?dential areas.
• Location-awareness imposes further difficulties
  for the testing of Web applications.
• Availability, available all the time and stable.

27
Characteristics of Web Applications

• 3. Development-related Characteristics
• a. The Development Team
• Multidisciplinarity , a combination of print
  publishing and software development, marketing
  and computing, and art and technology.
• Young average age , Web application developers
  are on average signi?cantly younger and thus
  less experienced.
• Community development , The development of open
  source software freely available on the Web and
  its integration in real applications is a very
  recent phenomenon.

28
Characteristics of Web Applications

• 3. Development-related Characteristics
• b. Technical Infrastructure
• Inhomogeneity, between the server and the
  browsers
• Immaturity, Because of the increasing
  time-to-market pressure, components used in Web
  applications are often immature, i.e. they either
  have bugs or lack the desired functionality.

29
Characteristics of Web Applications

• 3. Development-related Characteristics
• c. Process, The development process is the
  framework for all development-related
  characteristics.
• Flexibility, It is vital to react ?exibly to
  changing conditions, you cant only have a rigid
  plan.
• Parallelism, Due to the necessity for short
  development times and the fact that Web
  applications can often be split up into
  autonomous components
• design, implementation and quality assurance are
  often carried out simultaneously for different
  versions

30
Characteristics of Web Applications

• 3. Development-related Characteristics
• d. Integration
• Internal integration
• Web applications have to be integrated with
  existing
• legacy systems when existing content
• External integration
• the integration of content and services of
  external Web applications is a special
  characteristic of Web applications.
• integration on the Web
• 1. there are a very large number of sources
• 2. frequently changing
• 3. usually only few details are known about the
  properties of these sources.
• 4. the different sources are often very
  heterogeneous at various levels, be it at the
  data level, the schema level, or the data model
  level.

31
Characteristics of Web Applications

• Evolution, evolution is a characteristic that
  governs all three dimensions of product, usage
  and development.
• a. Continuous change, Web applications change
  rapidly due to constantly changing requirements
  or conditions, and this has two reasons users
  want the newest Web hype, and the used tools are
  also technology-driven.

32
Characteristics of Web Applications

• Evolution
• b. Competitive pressure, this due to
• The extremely high competitive pressure.
• the time-to market pressure .
• the necessity for a Web presence .
• And this leads to
• The shorter product lifecycles
• extremely short development cycles

33
Characteristics of Web Applications

• Evolution
• c. Fast pace
• time pressure on Web application development
  is due to the rapid change on the Web and the
  accordingly short life spans of Web applications
  or their frequency of updates.

34
Questions ?

• Q1) Mention the top problem areas of large-scale
  WA projects .
• Q2) Talk about 3 of Web application Categories
  briefly .
• Q3) The basic elements of hypertext models are
  ?
• Q4) Disorientation and Cognitive overload are the
  main problems caused by the Non-linearity of the
  Hypertext model . How to solve THEM ?
• Q5) What are the main Characteristics of the web
  application ?