4. ch 3-agile process

Chapter-3: Agile Development
Abdus Sattar
Senior Lecturer
Department of Computer Science and Engineering
Daffodil International University
Email: abdus.cse@diu.edu.bd

What is “Agility”?
Ability to move quickly and easily.
Effective (rapid and adaptive) response to
change
Effective communication among all
stakeholders
Drawing the customer onto the team
Organizing a team so that it is in control of
the work performed Yielding or Soft …
Rapid, incremental delivery of software 2

An Agile Process
3
An agile process characterized in a manner
that addressed three assumptions about the
majority of software:-
 It is difficult to predict in advance which software
requirements will persist and which will change.
 For many types of software design and construction are
enclosed.
 Analysis, design, construction and testing are not as
predictable.

12 Agility Principles
4
1. Our highest priority is to satisfy the customer through early and
continuous delivery of valuable software.
2. Welcome changing requirements, even late in development. Agile
processes harness change for the customer's competitive
advantage.
3. Deliver working software frequently, from a couple of weeks to a
couple of months, with a preference to the shorter timescale.
4. Business people and developers must work together daily
throughout the project.
5. Build projects around motivated individuals. Give them the
environment and support they need, and trust them to get the job
done.
6. The most efficient and effective method of conveying information
to and within a development team is face–to–face conversation.

12 Agility Principles(Cont..)
5
7. Working software is the primary measure of progress.
8. Agile processes promote sustainable development. The
sponsors, developers, and users should be able to maintain a
constant pace indefinitely.
9. Continuous attention to technical excellence and good design
enhances agility.
10. Simplicity – the art of maximizing the amount of work not
done – is essential.
11. The best architectures, requirements, and designs emerge
from self–organizing teams.
12. At regular intervals, the team reflects on how to become
more effective, then tunes and adjusts its behavior
accordingly.

Human Factors
6
• The process models use to the needs of the people and team,
not the other way around
• Key traits must exist among the people on an agile team and
the team itself:
• Competence.
• Common focus.
• Collaboration.
• Decision-making ability.
• Fuzzy problem-solving ability.
• Mutual trust and respect.
• Self-organization.

Extreme Programming(XP)
7
 XP uses an object oriented approach.
 XP encompasses a set of rules and practice that
occur within the context of four framework
activities.
 XP Planning
 XP Design
 XP Coding
 XP Testing

9
There are four basic activities that XP proposes for software development
process :
1. XP Planning :
- The planning activity begins with the creating of a set of stories that describe required
features and functionally for software to be built.
- Each stories is written by the customer and placed on an index card.
- The customer assign a value to the story on the overall business value of the feature
or function.
- ¨Members of the XP team the access each story and assign a cost measured in
development week to it.
2. XP Design:
- XP design follows the KIS-Keep it simple principle.
- A simple design is always preferred over a more complex representation.
- The design provides implementation giddiness for a story as it is written nothing less,
nothing more.
- The XP team conducts the design exercise using a process and the CRC cards are the
only design work product produced as the part of XP process.
- XP recommends the immediate creating of an operational prototype of that portion of
the design called spike solution.

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3. XP Coding :
- XP recommends that after stories are developed and preliminary design is done, the
team should not move to code, but rather develop a series of unit test.
- Once the code is complete, it can be unit tested immediately, thereby providing
instaneous feedback to the developers.
- During the coding activity is pair programming.
- XP recommends that two people work together at one computer work station to create
code for a story. This provides a mechanism for real time problem solving and real
time quality assurance.
4. XP Testing:
- The creation of unit test before coding commence is a key element of the XP
approach.
- The unit test that are created should be implemented using a framework the enable
them to be automated.
- Integration and validation testing of the system can occur a daily basis.
- XP acceptance test, also called customer test are specified by the customer and focus
on overall system.

Other Agile Process Models
11
Adaptive Software Development (ASD)
Scrum
Dynamic Systems Development Method (DSDM)
Crystal
Feature Drive Development (FDD)
Lean Software Development (LSD)
Agile Modeling (AM)
Agile Unified Process (AUP)

Adaptive Software Development(ASD)
12
 Originally proposed by Jim Highsmith
 ASD technique proposed for building complex
software and system.
 ASD focus on human collaboration and team-self-
organization.
 ASD incorporates three phases:-
 Speculation
 Collaboration
 Learning

Adaptive Software Development
13

ASD Three Phases
14
1. Speculation:
- During speculation , the project is initiated and adapted cycle planning is
conducted.
- Adapting cycle planning uses project initiation – information the customers
mission statement, project constraints and basic requirements to define the set of
release cycle.
2. Collaboration
- The collaboration approach is requiring theme in all agile methods, but
collaboration is not easy.
- It is not simply communicate, although communicate is a part of it.
- It is nota rejection individualism, because individual creativity plays on
important role in collaboration thinking.
- People working together must trust one another to:-
- Criticize without animosity
- Assist without resentment.
- Work as hard of harder as they do.
- Have the skill set to contribute to the work at hard
- Communicate problem

Adaptive Software Development
15
3. Learning
- ASD teams learns three ways:-
- Focus Group:
- The customer or end user provide feedback on software increments that
are being delivered.
- Formal technical review:
- ASD team members review the software components that are develop,
improving quality and learning as they proceed.
- Postmaster
- The ASD team becomes introspective , addressing its own performance
and process.

Dynamic Systems Development
(DSD) Method
16
 The Dynamic System Development method (DSDM) is an
agile software development approach that provides a
framework for building and maintain system which meet tight
time constraints through the use of incremental prototyping in
a controlled project environment.
 The DSDM life cycle defines, three iterative cycle precede by
two additional life cycle.
 Feasibility study
 Business study
 Functional model iteration
 Design and iteration
 Implementation

DSDM Iterative life cycle
17
 Feasibility study
 Established the basic business requirements and constraints associated with
the applicants to be built.
 Business study
 Establishes the functional information requirements that will allow the
applicants to provide business value.
 Functional model iteration
 Produce a set of incremental prototype that demonstrate functionality for the
customer.
 Design and iteration
 Revisits prototype built during the functional model iteration to ensure that
each has been engineered in a manner.
 Implementation
 Places the latest software increment into the operational environment.
 It should be noted that-
 The increment may not be 100 percent complete
 Changes may be requested as the increment is put into place.

Scrum Agile Process
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Scrum is an agile software development method that was
conceived by Jeff Sutherland and his development team in the
early 1990s.
In recent years, further development on the Scrum methods
has been performed by Schwaber and Beedle
Scrum principles are consistent with the agile manifesto and
are used to guide development activities within a process that
incorporates the following framework activities: requirements,
analysis, design, evolution, and delivery.

Scrum Agile Process
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Fig: Scrum Process Flow

Scrum Agile Principles
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 Small working teams are organized to maximize
communication, minimize overload and maximize sharing
tacit, informal knowledge.
 The process must be adaptable to both technical and
business changes – to ensure the best possible product is
produced.
 The process yields frequent software increment that can be
inspected, adjusted, tested , documented and built on.
 Development work and people who perform it are
partitioned into clean low coupling partitions or packets.
 Constant testing and documentation is preferred as the
product is built.
 The scrum process provides the ability to declare a
product done whenever required.

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References:
1. Software Engineering A practitioner’s
Approach
by Roger S. Pressman, 7th edition, McGraw Hill, 2010.
2. Software Engineering by Ian Sommerville,
9th edition, Addison-Wesley, 2011

4. ch 3-agile process

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