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CS485/540 Software EngineeringChapter 3 – Agile Process Models
Cengiz Günay
Fall 2013
Günay () Ch 3 Agile Process Fall 2013 1 / 11
What is wrong with Waterfall?
Waterfall = sequential assembly line
After Industrial Revolution of 1830, the Taylor model separatedmanagement from labour (e.g., Ford Motors)In 1950s Deming proposed to combine ’thinking’ and ’doing’.
Ignored in the US, adopted by Japan.Toyota and Matsushita surpassed American companies
In late 1970s, product development companies like Toyota, Honda,Fujitsu, 3M, HP, Canon, and NEC were all using overlappingproduction phasesIn 1990s, software industry abandoned waterfall-style development
From articles on Lean Development and Intro to Agile.
Günay () Ch 3 Agile Process Fall 2013 2 / 11
What is wrong with Waterfall?
Waterfall = sequential assembly lineAfter Industrial Revolution of 1830, the Taylor model separatedmanagement from labour (e.g., Ford Motors)
In 1950s Deming proposed to combine ’thinking’ and ’doing’.
Ignored in the US, adopted by Japan.Toyota and Matsushita surpassed American companies
In late 1970s, product development companies like Toyota, Honda,Fujitsu, 3M, HP, Canon, and NEC were all using overlappingproduction phasesIn 1990s, software industry abandoned waterfall-style development
From articles on Lean Development and Intro to Agile.
Günay () Ch 3 Agile Process Fall 2013 2 / 11
What is wrong with Waterfall?
Waterfall = sequential assembly lineAfter Industrial Revolution of 1830, the Taylor model separatedmanagement from labour (e.g., Ford Motors)In 1950s Deming proposed to combine ’thinking’ and ’doing’.
Ignored in the US, adopted by Japan.Toyota and Matsushita surpassed American companies
In late 1970s, product development companies like Toyota, Honda,Fujitsu, 3M, HP, Canon, and NEC were all using overlappingproduction phasesIn 1990s, software industry abandoned waterfall-style development
From articles on Lean Development and Intro to Agile.
Günay () Ch 3 Agile Process Fall 2013 2 / 11
What is wrong with Waterfall?
Waterfall = sequential assembly lineAfter Industrial Revolution of 1830, the Taylor model separatedmanagement from labour (e.g., Ford Motors)In 1950s Deming proposed to combine ’thinking’ and ’doing’.
Ignored in the US, adopted by Japan.Toyota and Matsushita surpassed American companies
In late 1970s, product development companies like Toyota, Honda,Fujitsu, 3M, HP, Canon, and NEC were all using overlappingproduction phases
In 1990s, software industry abandoned waterfall-style development
From articles on Lean Development and Intro to Agile.
Günay () Ch 3 Agile Process Fall 2013 2 / 11
What is wrong with Waterfall?
Waterfall = sequential assembly lineAfter Industrial Revolution of 1830, the Taylor model separatedmanagement from labour (e.g., Ford Motors)In 1950s Deming proposed to combine ’thinking’ and ’doing’.
Ignored in the US, adopted by Japan.Toyota and Matsushita surpassed American companies
In late 1970s, product development companies like Toyota, Honda,Fujitsu, 3M, HP, Canon, and NEC were all using overlappingproduction phasesIn 1990s, software industry abandoned waterfall-style development
From articles on Lean Development and Intro to Agile.
Günay () Ch 3 Agile Process Fall 2013 2 / 11
What is wrong with Waterfall?
Waterfall = sequential assembly lineAfter Industrial Revolution of 1830, the Taylor model separatedmanagement from labour (e.g., Ford Motors)In 1950s Deming proposed to combine ’thinking’ and ’doing’.
Ignored in the US, adopted by Japan.Toyota and Matsushita surpassed American companies
In late 1970s, product development companies like Toyota, Honda,Fujitsu, 3M, HP, Canon, and NEC were all using overlappingproduction phasesIn 1990s, software industry abandoned waterfall-style development
From articles on Lean Development and Intro to Agile.
Günay () Ch 3 Agile Process Fall 2013 2 / 11
These slides are designed to accompany Software Engineering: A Practitionerʼs Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. ! 2!
The Manifesto for Agile Software Development!
These slides are designed to accompany Software Engineering: A Practitionerʼs Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. ! 3!
What is “Agility”?! 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 …! Rapid, incremental delivery of software!
These slides are designed to accompany Software Engineering: A Practitionerʼs Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. ! 4!
Agility and the Cost of Change!
These slides are designed to accompany Software Engineering: A Practitionerʼs Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. ! 5!
An Agile Process! Is driven by customer descriptions of what is
required (scenarios)! Recognizes that plans are short-lived! Develops software iteratively with a heavy
emphasis on construction activities! Delivers multiple ʻsoftware incrementsʼ! Adapts as changes occur!
These slides are designed to accompany Software Engineering: A Practitionerʼs Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. ! 6!
Agility Principles - I!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.!
These slides are designed to accompany Software Engineering: A Practitionerʼs Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. ! 7!
Agility Principles - II!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.!
These slides are designed to accompany Software Engineering: A Practitionerʼs Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. ! 8!
Human Factors! the process molds 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.!
These slides are designed to accompany Software Engineering: A Practitionerʼs Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. ! 9!
Extreme Programming (XP)! The most widely used agile process, originally
proposed by Kent Beck! XP Planning!
Begins with the creation of “user stories”! Agile team assesses each story and assigns a cost! Stories are grouped to for a deliverable increment! A commitment is made on delivery date! After the first increment “project velocity” is used to
help define subsequent delivery dates for other increments!
These slides are designed to accompany Software Engineering: A Practitionerʼs Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. ! 10!
Extreme Programming (XP)! XP Design!
Follows the KIS principle! Encourage the use of CRC cards (see Chapter 8)! For difficult design problems, suggests the creation of “spike
solutions”—a design prototype! Encourages “refactoring”—an iterative refinement of the internal
program design! XP Coding!
Recommends the construction of a unit test for a store before coding commences!
Encourages “pair programming”! XP Testing!
All unit tests are executed daily! “Acceptance tests” are defined by the customer and excuted to
assess customer visible functionality!
These slides are designed to accompany Software Engineering: A Practitionerʼs Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. ! 11!
Extreme Programming (XP)!
unit testcontinuous integration
acceptance testing
pairprogramming
Release
user stories values acceptance test criteriaiteration plan
simple design CRC cards
spike solutions prototypes
refactoring
software incrementproject velocity computed
These slides are designed to accompany Software Engineering: A Practitionerʼs Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. ! 12!
Adaptive Software Development! Originally proposed by Jim Highsmith! ASD — distinguishing features!
Mission-driven planning! Component-based focus! Uses “time-boxing” (See Chapter 24)! Explicit consideration of risks! Emphasizes collaboration for requirements gathering! Emphasizes “learning” throughout the process!
These slides are designed to accompany Software Engineering: A Practitionerʼs Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. ! 13!
Adaptive Software Development!adaptive cycle planning uses mission statement project constraints basic requirementstime-boxed release plan
Requirements gathering JAD mini-specs
components implemented/tested focus groups for feedback formal technical reviewspostmortems
software incrementadjustments for subsequent cycles
Release
These slides are designed to accompany Software Engineering: A Practitionerʼs Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. ! 14!
Dynamic Systems Development Method! Promoted by the DSDM Consortium (www.dsdm.org)! DSDM—distinguishing features!
Similar in most respects to XP and/or ASD! Nine guiding principles!
• Active user involvement is imperative. !• DSDM teams must be empowered to make decisions.!• The focus is on frequent delivery of products. !• Fitness for business purpose is the essential criterion for acceptance of
deliverables.!• Iterative and incremental development is necessary to converge on an accurate
business solution.!• All changes during development are reversible.!• Requirements are baselined at a high level!• Testing is integrated throughout the life-cycle.!
These slides are designed to accompany Software Engineering: A Practitionerʼs Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. ! 16!
Scrum! Originally proposed by Schwaber and Beedle! Scrum—distinguishing features!
Development work is partitioned into “packets”! Testing and documentation are on-going as the
product is constructed! Work occurs in “sprints” and is derived from a
“backlog” of existing requirements! Meetings are very short and sometimes conducted
without chairs! “demos” are delivered to the customer with the time-
box allocated!
These slides are designed to accompany Software Engineering: A Practitionerʼs Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. ! 18!
Crystal! Proposed by Cockburn and Highsmith! Crystal—distinguishing features!
Actually a family of process models that allow “maneuverability” based on problem characteristics!
Face-to-face communication is emphasized! Suggests the use of “reflection workshops” to
review the work habits of the team!
These slides are designed to accompany Software Engineering: A Practitionerʼs Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. ! 19!
Feature Driven Development! Originally proposed by Peter Coad et al! FDD—distinguishing features!
Emphasis is on defining “features”!• a feature “is a client-valued function that can be
implemented in two weeks or less.”! Uses a feature template!
• <action> the <result> <by | for | of | to> a(n) <object>! A features list is created and “plan by feature” is
conducted! Design and construction merge in FDD!
These slides are designed to accompany Software Engineering: A Practitionerʼs Approach, 7/e (McGraw-Hill, 2009) Slides copyright 2009 by Roger Pressman. ! 21!
Agile Modeling! Originally proposed by Scott Ambler! Suggests a set of agile modeling principles!
Model with a purpose! Use multiple models! Travel light! Content is more important than representation! Know the models and the tools you use to create them! Adapt locally!
Agile Development (I)
Extreme Programming
XP: http://extremeprogramming.org/rules.html, refactoring:http://www.refactoring.comIndustrial XP: readiness, community, business justification, progressmanagement, retrospective logs, process improvement(http://industrialxp.org)Problems: requirements volatility, multiple customers, informalness,lack of formal design
Adaptive Software Development (ASD)
collaboration: constructive criticism, assist each other, work as hard asothers, have required skills, communicate(http://www.adaptivesd.com)
Günay () Ch 3 Agile Process Fall 2013 4 / 11
Agile Development (II)
Scrum
Created by Schwaber and Sutherland, 1995(http://controlchaos.com)Term comes from rugby
Dynamic Systems Development Method (DSDM)
80% of project can be done in 20% time (exponential curve)(http://www.dsdm.org)feasibility, business, functional iteration, design/build iteration,implementation
Crystal
maneuverable models for specific types of projects
Günay () Ch 3 Agile Process Fall 2013 5 / 11
Agile Development (III)
Feature Driven Devel. (FDD)
features ' user stories(http://www.featuredrivendevelopment.com)
Lean Soft. Devel (LSD)
Adapted from the Toyota Production SystemTrim the fat, delay decisions, just-in-time delivery.Use Kanban boards: visual system with cards (David Anderson, 2003)
Agile Modeling (AM)
http://www.agilemodeling.com
Günay () Ch 3 Agile Process Fall 2013 6 / 11
What is Scrum?
In 1993 Jeff Sutherland borrowed term “scrum” from Takeuchi andNonaka, “The New New Product Development Game” HarvardBusiness Review, 1986.Takeuchi and Nonaka compare high-performing, cross-functionalteams to the scrum formation used by Rugby teams.
What is Scrum?
In rugby, scrum is the power struggle between two teams to advanceon the field.It requires complete teamwork, hard work, and strength. Thatmeaning translates to software development.
Also see original article, Scrum Alliance.
Some Agile Statistics
State of Agile Survey 2012 (local copy), VersionOne:84% of developers use Agile69% companies use Agile at least in 25% of projects
Günay () Ch 3 Agile Process Fall 2013 11 / 11
Agile Dev Survey
Agile Methods & Practices
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"' Daily Standup
'o Iteration Planning
~ Unit Testing
A Retrospectives
e. Release Planning
~ Burndown/ Team-Based Estimation
3 Velocity
h Coding Standards
Continuous Integration
J Automated Builds
K Dedicated Product Owner
Integ rated Dev /QA
m Refactoring
VERSION ONE" Agile Made Easier
"' Open Workarea
o TDD
'f> Digital Taskboard
9 Story Mapping
~ Kanban
s Collective Code Ownership
t- Pair Programming
u Automated Acceptance Testing
v Analog Taskboard
w Continuous Deployment
>< Agile Games
j Cycle Time
z._ BDD
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Fact/FallacyTidbit
• Fact6Newtools&techniquescauseanini1allossofproduc1vityand/orquality
• Discussion– OperaHonalchangesmadetodayforimprovedproducHvitytomorrow– LearningcurvecausesproducHvity/qualitylossunHltoolortechniqueisfully
mastered– Thisgapposesdilemma:
• Timingofthechange(whencanwedothis?);• EvaluaHngexpectedbenefits;• Costtomakethechange;• DuraHonoflearningcurve(proporHonaltobenefit);• CollecHngmetricstoevaluatedecision(oncefullyadopted)
– Realbenefittypicallybetween5%and35%(seeFact5,nextlecture)
FromRobertGlass,“Facts&FallaciesofSoCwareEngineering”
CS‐584/Fall2009/EmoryU 3