BPR IN SOFTWARE ENGINEERING - academics.epu.ntua.gr

BPR IN SOFTWARE ENGINEERING Business Process Reengineering by Lampathaki F., Koussouris S., Psarras J.

Decision Support Systems Laboratory, NTUA Business Process Reengineering 2013 - BPR in Software Engineering

Software Development Life Cycle


Requirements Analysis

Design

Implementation Testing

Evolution

The Waterfall Model 1/2

•  A sequential design process flowing steadily downwards (like a waterfall)

•  Originates in the manufacturing and construction industries •  highly structured physical environments •  after-the-fact changes are prohibitively

costly, if not impossible.

•  Adoption for Software Development was easy as no other models existed


The Waterfall Model 2/2

The Original Royce’s model: • Requirements specification • Design • Construction (Coding) •  Integration •  Testing and Debugging •  Installation • Maintenance

Move over to the next phase only when its preceding phase is completed


Requirements

Design

Implementation

Verification

Maintenance

Why to use the Waterfall Model •  Time spent early on making sure requirements and design are correct saves much time and

effort later. •  Program requirements should be set in stone before design begins •  The program's design should be perfect before people begin to implement the design •  …

•  Places emphasis on documentation (such as requirements documents and design documents) as well as source code.

•  Knowledge is lost if team members leave the project •  Solid documentation is a key to sustainability and quick catch-up

•  Simple approach and disciplined way to work •  A structured approach progressing in a linear manner •  Easily understandable and explainable phases •  Identifiable milestones

•  Suits software projects that: •  are stable (especially those projects with unchanging requirements, such as with shrink wrap software) •  Where designers will be able to fully predict problem areas of the system and produce a correct design

before implementation is started


Why NOT to use the Waterfall Model Life is full of changes!!! "measure twice - cut once” is a nice method for “solid” and “unchangeable” environments

•  Some belive Waterfall is a bad idea in practice - impossible for any non-trivial project to finish a phase of a software product's life cycle perfectly before moving to the next phases and learning from them

•  Requirements change •  Designers are not aware of limitations •  Project stakeholders (non-IT personnel) are not fully aware of the

capabilities opportunities of the technology •  Coding kicks-back on the design •  Details become known only during working with the systems

“Software development process’ requirements and limitations cannot be entirely known before completion.” McConnell


Verification & Validation (V&V) What is Verification & Validation ?

•  Verification: Are we building the product right? •  Validation: Are we building the right product?

Verification: The process of evaluating software to determine whether the products of a given development phase satisfy the conditions imposed at the start of that phase •  Verification ensures that every step in the process of building the software delivers

the correct product. Validation: The process of evaluating software during or at the end of the development process to determine whether it satisfies specified requirements.

•  Validation ensures that software being developed satisfies functional and all other requirements.


The V Model (appropriate for Waterfall approach)


The Spiral Model Combines some key aspect of the waterfall model and rapid prototyping methodologies Provides emphasis in deliberate iterative risk analysis (particularly suited to large-scale complex systems)

Includes a number of iterations, with the four quadrant diagram representative of the following activities: •  Determine the objectives, alternatives, and constraints on the new

iteration •  Evaluate alternatives and identify and resolve risk issues •  Develop and verify the product for this iteration •  Plan the next iteration

Restrictive conditions: •  Requires customers to accept the risk analysis and act on it •  Trust in the developer •  Willingness to spend more to fix the issues •  Risk analysis is costly •  Extra role for Software developers


Rapid Application Development (RAD) Minimal planning in favor of rapid prototyping Software is written much faster == Meeting updated requirements is easier Involves methods like iterative development and software prototyping Structured techniques and prototyping are especially used to define users' requirements and to design the final system


Preliminary data models and

business process models using structured

techniques

Requirements verification based on prototype

Refinement of data and

process models.

BRP and Agile Techniques BPR is taking the form of a quick-reacting, highly flexible project methodology Teams are looking at delivering bits of improvements, instead of huge deliverables at once. (small packages every 6-8 weeks rather than larger >6months) New methods and work processes are needed to offer these options

AGILE techniques


Agile Business Process Management A way to automate and manage structured, repeatable business processes.

•  From the BPM side of the equation, provides automated and managed structures to provide repeatable business processes

•  From the agile side of the equation, provides the ability to act immediately, in real time to circumstances that are unforeseen in those processes.

Best suite for enterprises where: •  Unpredictable is common •  Business processes cannot change quickly enough for business practices •  Knowledge workers need to focus on achieving goals rather than repetitive tasks

Characteristics of Agile BPM: •  Users can change processes on the fly responding to current conditions but without changing

the model •  An ability to deal with unstructured work •  Knowledge of the conditions those process are operating in provided by predictive analytics


Agile Software Development Introduced in 2001 by the Agile Manifesto A group of software development methods based on: •  iterative and incremental development •  requirements and solutions that evolve through collaboration between self-

organizing, cross-functional teams.

A conceptual framework that promotes foreseen interactions throughout the development cycle: •  Adaptive planning •  Evolutionary development and delivery •  A time-boxed iterative approach •  Rapid and flexible response to change


Agile Manifesto 1/2

1.  Individuals and interactions over processes and tools

2.  Working software over comprehensive documentation

3.  Customer collaboration over contract negotiation

4.  Responding to change over following a plan

While there is value in the items on the right, we value the items on the left more!

http://agilemanifesto.org


Agile Manifesto 2/2

The Agile Manifesto is based on twelve principles (according to Beck):

1.  Customer satisfaction by rapid delivery of useful software 2.  Welcome changing requirements, even late in development

3.  Working software is delivered frequently (weeks rather than months)

4.  Working software is the principal measure of progress

5.  Sustainable development, able to maintain a constant pace

6.  Close, daily cooperation between business people and developers

7.  Face-to-face conversation is the best form of communication (co-location)

8.  Projects are built around motivated individuals, who should be trusted

9.  Continuous attention to technical excellence and good design 10.  Simplicity—the art of maximizing the amount of work not done—is essential

11.  Self-organizing teams

12.  Regular adaptation to changing circumstances


Agile Methods Characteristics 1/2

•  Agile methods break tasks into small increments •  Minimal planning, not involving long-term planning.

Iterations: •  Iterations are short time frames (timeboxes) that typically last from 1 to 4 weeks. •  Each iteration involves a cross functional team working in all functions: planning, requirements

analysis, design, coding, unit testing, and acceptance testing. •  Iteration’s end means a working product is there

Minimizing the overall risk and enabling rapid adaptation to new/updated requirements The team: •  Decides how to meet goals and which goals to set •  Emphasizes on face-to-face communication over written documents •  Contain a customer representative (interfacing with clients only through him) •  There is no (or limited) hierarchy in the team.


Agile Methods Characteristics 2/2 Meetings: •  A routine and formal daily face-to-face team meeting (15mins) •  At the same time •  At the same place •  De-briefing on previous day developments •  Setting day’s targets

Working software is the primary measure of progress!

Tools and techniques used: •  Continuous integration •  Automated or xUnit tests •  Pair programming •  Test-driven development •  Design patterns •  Domain-driven design •  Code refactoring


Comparison with Waterfall method Agile methods lie on the adaptive side rather on the predictive one.


Notable Methods •  Agile Modeling •  Agile Unified Process (AUP) •  Crystal Clear •  Crystal Methods •  Dynamic Systems Development Method (DSDM) •  Extreme Programming (XP) •  Feature Driven Development (FDD) •  Graphical System Design (GSD) •  Kanban •  Lean software development •  Scrum •  Velocity tracking •  Software Development Rhythms


Agile and Software development life cycle Can be used: •  For full coverage of the development life cycle

•  Holistic (e.g. Dynamic systems development method (DSDM), IBM Rational Unified Process (RUP))

•  Many methods are applicable from the requirements specification phase on (e.g. feature-driven development (FDD))

•  For different aspects/steps of the life cycle •  Development practices (e.g extreme programming, pragmatic programming, agile

modeling), •  Management Practices (e.g Scrum).


Criticism of Agile Methods •  Inefficient in large organizations or specific projects

•  Best for developmental and non-sequential projects

•  Too extreme for some enterprises who adopt a hybrid approach

An management trend J •  Includes many of the properties of past management trends •  New jargon for existing processes •  External consultants •  Measurement of metrics defined by itself (e.g. velocity)

Software Engineers may think Agile is the way that Developers invented to try to get rid of them J


Agile Testing The V Model is not applicable as is! In Agile, testing is not a separate phase, but an integral part of software development, along with coding and of course…. follows the principles of agile software development •  Testing and coding are done incrementally and iteratively •  Each feature is build up until it provides value to be release •  Covers all types of testing. •  Involves all members of the agile team Specification by example (acceptance test-driven development), is used to capture examples of desired and undesired behavior and guide coding.


When does Agile work as planned? •  The organization is ready to be agile (Buy In).

Both client and contractor.

•  The client is the Product Owner and understands what that entails (or an outside PO has enough time to become a Subject Matter Expert).

•  The Product Owner is available to work with the implementation team: clarifying requirements, setting work priorities, reviewing completed work.

•  The Product Owner acts as the conduit between stakeholders and implementation team.


SCRUM Adapted from Mountain View Software Scrum Redistributable presentation


We’re losing the relay race “The… ‘relay race’ approach to product development… may conflict with the goals of maximum speed and flexibility. Instead a holistic or ‘rugby’ approach—where a team tries to go the distance as a unit, passing the ball back and forth—may better serve today’s competitive requirements.”

Hirotaka Takeuchi and Ikujiro Nonaka, “The New New Product Development Game”, Harvard Business Review, January 1986


Scrum in 100 words • Scrum is an agile process that allows us to focus on delivering

the highest business value in the shortest time.

• It allows us to rapidly and repeatedly inspect actual working software (every two weeks to one month).

• The business sets the priorities. Teams self-organize to determine the best way to deliver the highest priority features.

• Every two weeks to a month anyone can see real working software and decide to release it as is or continue to enhance it for another sprint.


Scrum has been used by: • Microsoft • Yahoo • Google • Electronic Arts • High Moon Studios • Lockheed Martin • Philips • Siemens • Nokia • Capital One • BBC •  Intuit

•  Intuit • Nielsen Media • First American Real Estate • BMC Software •  Ipswitch • John Deere • Lexis Nexis • Sabre • Salesforce.com • Time Warner • Turner Broadcasting • Oce


Scrum has been used for: •  Commercial software •  In-house development •  Contract development •  Fixed-price projects •  Financial applications •  ISO 9001-certified applications •  Embedded systems •  24x7 systems with 99.999%

uptime requirements •  the Joint Strike Fighter

• Video game development • FDA-approved, life-critical systems • Satellite-control software

• Websites • Handheld software

• Mobile phones • Network switching applications

•  ISV applications

• Some of the largest applications in use


Scrum Characteristics • Self-organizing teams • Product progresses in a series of month-long “sprints” • Requirements are captured as items in a list of “product backlog” • No specific engineering practices prescribed • Uses generative rules to create an agile environment for delivering projects

• One of the “agile processes”



Simple

Complex Anarchy

Technology

Req

uire

men

ts

Far from Agreement

Close to Agreement

Clo

se to

C

erta

inty

Far f

rom

C

erta

inty

Source: Strategic Management and Organizational Dynamics by Ralph Stacey in Agile Software Development with Scrum by Ken Schwaber and Mike Beedle.

Project noise level

Scrum Overview

Cancel Gift wrap

Return

Sprint 2-4 weeks

Return

Sprint goal

Sprint backlog Potentially shippable product increment

Product backlog

Coupons Gift wrap Coupons

Cancel

24 hours


Putting it all together


Sprints • Scrum projects make progress in a series of “sprints”

•  Analogous to Extreme Programming iterations

•  Typical duration is 2 - 4 weeks or a calendar month at most

• A constant duration leads to a better rhythm

• Product is designed, coded, and tested during the sprint


Sequential vs. overlapping development

Source: “The New New Product Development Game” by Takeuchi and Nonaka. Harvard Business Review, January 1986.

Rather than doing all of one thing at a time...

...Scrum teams do a little of everything all the time

Requirements Design Code Test


No changes during a sprint

• Plan sprint durations around how long you can commit to keeping change out of the sprint

Change


Scrum framework

• Product Owner • ScrumMaster • Team

Roles

• Sprint planning • Sprint review • Sprint retrospective • Daily scrum meeting

Ceremonies

• Product backlog • Sprint backlog • Burndown charts

Artifacts


Scrum framework


Ceremonies


Artifacts


Roles

Product owner • Define the features of the product

• Decide on release date and content

• Be responsible for the profitability of the product (ROI)

• Prioritize features according to market value

• Adjust features and priority every iteration, as needed

• Accept or reject work results


The ScrumMaster •  Represents management to the project

•  Responsible for enacting Scrum values and practices

•  Removes impediments

•  Ensure that the team is fully functional and productive

•  Enable close cooperation across all roles and functions

•  Shield the team from external interferences


The team •  Typically 5-9 people

•  Cross-functional:

•  Programmers, testers, user experience designers, etc.

•  Members should be full-time

•  May be exceptions (e.g., database administrator)

•  Teams are self-organizing

•  Ideally, no titles but rarely a possibility

•  Membership should change only between sprints



Roles

Scrum framework


Artifacts


Ceremonies

Sprint planning meeting

Sprint prioritization

•  Analyze and evaluate product backlog

•  Select sprint goal

Sprint planning

•  Decide how to achieve sprint goal (design)

•  Create sprint backlog (tasks) from product backlog items (user stories / features)

•  Estimate sprint backlog in hours

Sprint goal

Sprint backlog

Business conditions

Team capacity

Product backlog

Technology

Current product

Ceremonies


Sprint planning •  Team selects items from the product backlog they can

commit to completing • Sprint backlog is created

•  Tasks are identified and each is estimated (1-16 hours) •  Collaboratively, not done alone by the ScrumMaster

• High-level design is considered


As a vacation planner, I want to see photos of the hotels.

Code the middle tier (8 hours) Code the user interface (4) Write test fixtures (4) Code the foo class (6) Update performance tests (4)

The daily Scrum •  Parameters

•  Daily •  15-minutes •  Stand-up

•  Not for problem solving •  Whole world is invited

•  Only team members, ScrumMaster, product owner, can talk

•  Helps avoid other unnecessary meetings


Everyone answers 3 questions


These are not status updates for the ScrumMaster They are commitments in front of peers

What did you do yesterday? 1

What will you do today? 2

Is anything in your way? 3

The sprint review • Team presents what it accomplished during the sprint

• Typically takes the form of a demo of new features or underlying architecture

•  Informal •  2-hour prep time rule •  No slides

• Whole team participates

•  Invite the world


Sprint retrospective • Periodically take a look at what is and is not working

• Typically 15–30 minutes

• Done after every sprint

• Whole team participates •  ScrumMaster •  Product owner •  Team •  Possibly customers and others


Start / Stop / Continue Whole team gathers and discusses what they’d like to:


Start doing

Stop doing

Continue doing This is just one of many ways to

do a sprint retrospective.


Roles Scrum framework



Ceremonies


Artifacts

Product backlog •  The requirements

•  A list of all desired work on the project

•  Ideally expressed such that each item has value to the users or customers of the product

•  Prioritized by the product owner

•  Reprioritized at the start of each sprint

This is the product backlog


A sample product backlog


Backlog item Estimate

Allow a guest to make a reservation 3

As a guest, I want to cancel a reservation. 5

As a guest, I want to change the dates of a reservation. 3

As a hotel employee, I can run RevPAR reports (revenue-per-available-room) 8

Improve exception handling 8

... 30

... 50

The sprint goal A short statement of what the work will be focused on during the sprint


Database Application

Financial services

Life Sciences Support features necessary for population genetics studies.

Support more technical indicators than company ABC with real-time, streaming data.

Make the application run on SQL Server in addition to Oracle.

Managing the sprint backlog •  Individuals sign up for work of their own choosing

•  Work is never assigned

•  Estimated work remaining is updated daily

•  Any team member can add, delete or change the sprint backlog

•  Work for the sprint emerges

•  If work is unclear, define a sprint backlog item with a larger amount of time and break it down later

•  Update work remaining as more becomes known


A sprint backlog

Tasks Code the user interface

Code the middle tier

Test the middle tier

Write online help

Write the foo class

Mon 8

16

8

12

8

Tues 4

12

16

8

Wed Thur

4

11

8

4

Fri

8

8

Add error logging

8

10

16

8

8


A sprint burndown chart


Hou

rs

Hou

rs

40

30

20

10

0 Mon Tue Wed Thu Fri

Tasks Code the user interface

Code the middle tier

Test the middle tier

Write online help

Mon 8

16

8

12

Tues Wed Thur Fri 4

12

16

7

11

8

10

16 8

50


Scalability • Typical individual team is 7 ± 2 people

• Scalability comes from teams of teams

• Factors in scaling • Type of application • Team size • Team dispersion • Project duration

• Scrum has been used on multiple 500+ person projects


Scaling through the Scrum of scrums Decision Support Systems Laboratory, NTUA Business Process Reengineering 2013 - BPR in Software Engineering

1.  What has your team done since we last met? 2.  What will your team do before we meet again? 3.  Is anything slowing your team down or getting in their way? 4.  Are you about to put something in another team’s way?

Scrum of scrums of scrums


QUESTIONS? [email protected] Dr. Lampathaki F. - [email protected] Dr. Koussouris S. - [email protected]


BPR IN SOFTWARE ENGINEERING - academics.epu.ntua.gr

Documents

Transcript of BPR IN SOFTWARE ENGINEERING - academics.epu.ntua.gr