The Essential Software Engineering Approach to Requirements Engineering

Transcription

1 The Essential Software Engineering Approach to Requirements Engineering Presented at the BASSA 2012 Conference 4 & 5th September 2012 Protea Hotel Balalaika, Sandton From Sight to Insyte

2 Introduction Setting the scene: BABOK on Requirements Engineering Situational Responses SEMAT

3 BABOK on Requirements Engineering Elicitation, analysis & communication of requirements, With objective of ensuring Visibility & Understanding by stakeholders, Is central to discipline of Business Analysis Based on statement in BABOK 2.0

4 Requirements Analysis One of the BABOK Knowledge Areas Involving execution of tasks And use of techniques A key task: Plan the Business Analysis Approach Requiring a situational response Sometimes Waterfall Sometimes Agile

5 Situational Tension (Explained in the (slighted adapted) Manifesto for Agile Software Development) ( We are uncovering better ways of satisfying requirements when developing software by doing it and helping others do it. Through this work we have come to value: Individuals and interactions over processes and tools Working software over comprehensive documentation Customer collaboration over contract negotiation Responding to change over following a plan That is, while there is value in the items on the right, we value the items on the left more.

6 Calls for a Chaordic Response Chaordic The behaviour of any self-governing organism, organization or system which harmoniously blends characteristics of order and chaos. Patterned in a way dominated by neither chaos nor order. Characteristic of the fundamental organising principles of evolution and nature (Dee Hock - Birth of the Chaordic Age Berrett-Koehler, 1999)

7 A Chaordic Response PROVIDING OVERSIGHT Low Ceremony High Ceremony (Empirical) (Defined) APPROACH TO MANAGEMENT AND CONTROL Organic Conventional (Empirical) (Defined) APPROACH TO PRODUCING THE RESULTS DOING THE WORK APPROACH TO PRODUCING THE RESULTS Organic Conventional (Empirical) (Defined) APPROACH TO MANAGEMENT AND CONTROL Low Ceremony High Ceremony (Empirical) (Defined)

8 Defined and Empirical Processes If a process can be fully defined, with all things known about it so that it can be designed and run repeatably with predictable results, It is known as a defined process. Such as the conventional, Waterfall approach If all things about a process are not fully known only what generally happens when you mix the inputs, and what to measure and control to get the desired output They are called empirical processes. Such as the organic, Iterative approach

9 Insyte s Complex-Adaptive Situational Model (CASM) DECREASING VISIBILITY Low Ceremony High Ceremony CRAFTED QUALITY (Agile) RUP Type III APPROACH TO PRODUCING THE RESULTS Organic Conventional (Empirical) (Defined) INCREASING PROCESS CLARITY MANAGED COSTS (WetAgile TM ) RUP Type IV (Empirical) (Defined) APPROACH TO MANAGEMENT AND CONTROL CHAORDIC BAND OF FEASIBILITY SELF DIRECTED RUP Type I INCREASING PARALLELISM Organic Conventional (Empirical) (Defined) APPROACH TO PRODUCING THE RESULTS CONTROLLED QUALITY (Waterfall) RUP Type II Adapted from Towards Understanding The Relationship Between Process Capability And Enterprise Flexibility Myburgh 2005 RUP (Rational Unified Process) is a trademark of IBM APPROACH TO MANAGEMENT AND CONTROL Low Ceremony High Ceremony (Empirical) (Defined) INCREASING FORMALITY WetAgile is a trademark of Steve Pieczko

10 Characteristics: Crafted Quality (Agile) and Controlled Quality (Waterfall) Management Characteristics Customer Relations Planning & control Project Communications Technical Characteristics Requirements Definition Development Test Application Characteristics Project goals Project size Application environment Personnel Characteristics Customer Characteristics Developer Characteristics Organizational Culture Process Characteristics Type Repeatability Multi-tasking (Adapted from Balancing Agility and Discipline Boehm and Turner 2004)

11 Technical Characteristics REQUIREMENTS DEVELOPMENT TESTING CRAFTED QUALITY (AGILE RUP TYPE III) Prioritised informal stories and test cases Undergoing unforeseeable change Evolving architecture Simple design Short increments Re-work assumed inexpensive CONTROLLED QUALITY (WATERFALL RUP TYPE II) Formalised project, capability, interface, quality, architecture Foreseeable evolution requirements Guided by full-scope architecture Extensive design REQUIRES A SITUATIONAL APPROACH TO REQUIREMENTS ENGINEERING Executable test cases define requirements Longer increments Re-work assumed expensive Documented test plans and procedures (Adapted from Balancing Agility and Discipline Boehm and Turner 2004)

12 Essential SEMAT Approach to Requirements Engineering Software Engineering Method and Theory ( Launched in September 2009 by Ivar Jacobson, Bertrand Meyer and Richard Soley To re-found software engineering based on Solid theory, Proven principles and Best practices. Includes a kernel of widely-agreed elements, extensible for specific uses

13 Fundamental problem Every one of us knows how to engineer our requirements, But as a community we have No widely accepted common ground Use Case Descriptions User Stories Declarative Requirements Etc.

14 Start from a common ground The Kernel: Should be harvested from a large number of methods Is practice and method agnostic. Includes elements which are universal for all software engineering efforts. The essence of software engineering (including Requirements Engineering)

15 Extending the Kernel With Practices The Kernel is Universal. By adding Practices on top of the Kernel you create a specific Method. Practices such as Use Cases, Test-Driven Development, Etc

16 The Kernel provides a shared frame of reference

17 The Kernel Enables Situational Software Engineering

18 Organizing the Kernel AREAS OF CONCERN Alphas: What we work with and aspire to

19 What is an Alpha? An essential element of the software engineering endeavor that is: Relevant to an assessment of the progress and health of the endeavor. Progress and health of things we ASPIRE to Alpha is an acronym for: Aspiration-Led Progress Health Attribute, or an Abstract-Level Progress Health Attribute

20 The Seven Kernel Alphas

21 The Alpha Structure

22 Requirements: One of the Alphas

23 Requirements: One of the Alphas

24 Checklist for Requirements The initial set of stakeholders agrees that a system is to be produced. The stakeholders that will use the new system are identified. The stakeholders that will fund the initial work on the new system are identified. There is a clear opportunity for the new system to address.

25 Using the Kernel in Practice

26 Using the Kernel in Practice

27 What s New About Semat? Focus is the practitioners, not the process engineers Focus is Method Use and Adaption, not Method Description Semat is inclusive and not exclusive it includes all relevant methods and practices ( good or bad ) There is a small Kernel of essential practices For small teams and large organizations Practices from the bottom, and not process from the top Separation of concerns is a fundamental principle Light and agile in working with methods The process is what the team does. Adaption happens dynamically as a retrospective of what the team did through a feedback loop

28 What You Can Do Now BECOME A SUPPORTER READ THE BOOK

29 References 1. Barry Myburgh: Towards understanding the relationship between Process Capability and Enterprise Flexibility, Proceedings of the ImproveIT Conference, (Updated September 2010) 2. Ivar Jacobson and Bertrand Meyer: Methods need theory, Dr. Dobb's Journal, August 06, Online at 3. Ivar Jacobson and Ian Spence: Why we need a theory for software engineering, Dr. Dobb's Journal, October 02, Online at 4. Ivar Jacobson, Bertrand Meyer, and Richard Soley: Call for Action: The Semat Initiative, Dr. Dobb's Journal December 10, Online at 5. Ivar Jacobson, Bertrand Meyer, and Richard Soley: The Semat Vision Statement, online at 6. Ivar Jacobson, Shihong Huang, Mira Kajko-Mattsson, Paul McMahon, Ed Seymour. Semat Three Year Vision, Programming and Computer Software 38(1): 1-12 (2012), Springer DOI: /S Essence Kernel and Language for Software Engineering, (OMG Document number: ad/ ) A proposal submitted to OMG RFP (OMG Document ad/ )