ITEC 6120 System Requirements Management Luiz Marcio Cysneiros Fall 2017

Textbook Requirements engineering : processes and techniques http://www.yorku.ca/cysneiro/courses.htm Textbook Requirements engineering : processes and techniques Gerald Kotonya and Ian Sommerville. Publication info: Chichester ; New York : J. Wiley & Sons, c1998. ISBN: 0471972088

Scoring Oral Presentation + Leading discussion 45% Final exam 55% http://www.yorku.ca/cysneiro/courses.htm Scoring Oral Presentation + Leading discussion 45% Final exam 55%

Directions email cysneiro@yorku.ca office TEL Building 3053 http://www.yorku.ca/cysneiro/courses.htm Directions email cysneiro@yorku.ca office TEL Building 3053 Office Hours – Tuesday: 2:30 PM to 3:30 PM Wednesday 5:00 PM to 6:30 PM http://www.yorku.ca/cysneiro/courses.htm

Course Objectives Understanding RE Research in RE RE State-of-the-art for research and Practice What does a RE do ? Techniques Methods Process Understanding RE Research in RE Existing Methods Where it will lead us ? Alternatives ?

The Course at a Glance Introduction Elicitation Modelling Analysis Management Advanced Topics: Goal/Agent-Oriented RE, Social Modelling for RE

Nowadays World Software-Intensive Systems Software vs Systems ? Software Alone is useless Hardware Alone is useless Both only exist when used to support any human activity Software+Hardware+People+activities Systems Intensive use of software systems

Systems/Requirements Analyst Person who performs systems analysis Different possible job titles Systems analyst Business systems analyst Business analyst Process analyst Requirements engineer Requirements analyst Product owner Role is evolving Systems analyst [WB*] a specialist who studies the problems and needs of an organization to determine how people, data, processes, and information technology can best accomplish improvements for the business * [WB - Whitten, J. L., Bentley, L. D. Systems Analysis and Design Methods,7th edition, Irwin McGraw-Hill, 2007]

Skills for a Systems Analyst Problem solving Business acumen Domain expertise IT knowledge (IS, various technologies, programming) Communication Dealing with business and technical (IT) people Interviewing, meeting facilitation, etc. Liaison b/w business and IT

What is a System? A system is a group of interrelated components that function together to achieve a desired result [WB] System [Alter] Social – no significant use of technology Sociotechnical – human participants make use of technology Automated – fully automated once triggered by people, events, etc. An information system (IS) is an arrangement of people, data, processes, and information technology that interact to collect, process, store, and provide as output the information needed to support an organization [WB]

More System Definitions Macmillan English Dictionary A set of connected things that work together for a particular purpose A central heating system I decided to install a security system to prevent any break-ins. The city’s inadequate public transportation system

More System Definitions Ackoff [Russell L. Ackoff. Towards a System of Systems Concepts. Management science, 17(11), 661-71. 1971] Set of (at least two) interrelated elements/components Each element is connected to every other element (directly or indirectly) No subset of elements is unrelated to any other subset Weinberg [Gerald M. Weinberg. Introduction to General Systems Thinking, 1975] “A system is a way of looking at the world” Systems don’t really exist! Just a convenient way to describe things (e.g., just like “sets”)

Nowadays World Software systems present opportunities for change It may be complex but should also be adaptable Changes very quickly and some times very frequently A New System may change human activities in many significant ways Paperless Hospitals Virtual Doctors Virtual Surgeries Phone Chat Facebook

Nowadays World Software Systems became Ubiquitous Even Refrigerators have software systems today However, we are frequently disappointed with them If it doesn’t work chances are : Who designed didn’t understood what was needed It is been used for different purposes than the original intended

Requirement: (Macmillan English Dictionary) something that is needed in order for something to happen: Check the car’s fuel requirements. Good insulation can cut the energy requirements of a house by more than half. something that a rule, law, contract, etc. states that you must do: Do these goods comply with our safety requirements? requirement of: It is usually a requirement of banks and investors that a new company is formed to effect the management buy-out. requirement for: Applicants must satisfy the requirements for admission to the university.

System: (Macmillan English Dictionary) [count] a set of connected things that work together for a particular purpose: a central heating system I decided to install a security system to prevent any break-ins. the city’s inadequate public transportation system System: some part of a reality that can be observed to interact with its environment a set of interrelated components, or sub-systems, with a particular purpose. 1) there are 2 components at least, 2) each of which is related (directly or indirectly) to every other component and, 3) no sub set of which is unrelated to any other subset. Ackoff, Russell L., (1971). Towards a System of Systems Concepts. Management science, 17(11), 661-71. SOFTWARE VS SYSTEMS ?

Context Software crises continues Denver Airport More than 50 million US $ due to errors in the baggage control system London Ambulance Service The system was deactivated one day after its deployment due to many errors. Most of them related to non-functional requirements such as: Safety, Reliability and Usability

Software Crises Flaws in the Production Process Unhappy Clients High costs

Europe Questionnaire sent to 3.805 companies showed: For the Analysts, Major problems are: Requirements specification (53%) Requirements Management (43%) Documentation (36%) Test (35%)

USA Requirements Management (Also know as Requirements Engineering – RE) is seen as one of the most important problems to be overcome in order for companies to achieve level 2 in the SEI’s (Software Engineering Institute – Carnegie Mellon) CMM (Capability Maturity Model) SEI has recently released a package aiming to transfer technology in RE to facilitate companies’ certification

Good News … “26% of the Software projects were considered a success.” Standish Group, CHAOS Report, 2000

Bad News… Meaning that 74% have FAILED! Standish Group, CHAOS Report, 2000

Even Worse: CHAOS Report, 2015. The Standish Group. “29% of the Software projects were considered a success.” Almost two-fold increase from 1994! But this means that 71% were not (fully) successful!

CHAOS Reports Widely cited (since 1994) Type 1. Project success: completed on-time and on-budget, with all features and functions as initially specified Type 2. Project challenged: completed and operational but over- budget, over the time estimate, and offers fewer features and functions than originally specified Type 3. Project impaired: project is canceled at some point during the development cycle

From the CHAOS Reports

From the CHAOS Reports

From the CHAOS Reports

Tom De Marco “56% of the errors in a software can be traced back to the requirements phase” The later an error is detected the more expensive is to fix it. Many errors are done during Requirements elicitation and analysis

Many errors in requirements can (and should) be detected early in the software development life cycle. Typical errors include: Use of incorrect facts, omission, inconsistency and ambiguity. Errors in requirements specification are one of the major concerns for software industry.

200 x Cost to Repair Analysis Design Code Unit Test Integration Test Maintenance Stage when the Error is found

Definition of RE “ Requirements engineering is a sub-area of Software Engineering that studies the process of defining the requirements for a software-to-be. It is a new area started in 1993 when the 1st International Symposium on RE was organized. The process for defining requirements is an interface between the desires and the needs of the clients and a future implementation of these requirements as a software.”

Goals Understand the needs and support the client’s desires. Provide the Requirements Engineer with methods, techniques and tools to help on the process of understanding and registering what a software must do.

Fred Brook’s Brook adds: “The most difficult part of building a software system is to decide, precisely, what must be built. No other part of the work can undermine so badly the resulting software if not done correctly. No other part is so difficult to fix later.”

Factors influencing requirements Personality and status of stakeholders The personal goals of individuals within an organization The degree of political influence of stakeholders within an organization

RE process problems Lack of stakeholder involvement Business needs not considered Lack of requirements management Lack of defined responsibilities Stakeholder communication problems Over-long schedules and poor quality requirements documents Many confuse it with Design Pressure from the Market “It has to be ready next week” Clients keep adding and changing things

Process improvement Process improvement is concerned with modifying processes in order to meet some improvement objectives Improvement objectives Quality improvement Schedule reduction Resource reduction

Planning process improvement What are the problems with current processes? What are the improvement goals? How can process improvement be introduced to achieve these goals? How should process improvements be controlled and managed?

Process maturity Process maturity can be thought of as the extent that an organization has defined its processes, actively controls these processes and provides systematic human and computer-based support for them. The SEI’s Capability Maturity Model is a framework for assessing software process maturity in development organizations

Capability maturity model

RE process maturity levels Initial level No defined RE process. Suffer from requirements problems such as requirements volatility, unsatisfied stakeholders and high rework costs. Dependent on individual skills and experience. Repeatable level Defined standards for requirements documents and policies and procedures for requirements management. Defined level Defined RE process based on good practices and techniques. Active process improvement process in place.

Maturity levels Managed level Optimizing level Detailed measurements of both process and product quality are collected and used to control the process. Optimizing level The organization has a continuous process improvement strategy, based on objective measurements in place.

Good practice for RE process improvement RE processes can be improved by the systematic introduction of good requirements engineering practice Each improvement cycle identifies good practice guidelines and works to introduce them in an organization

Project Management + Mature Process Metrics ! A critical tool If you don’t have metrics you can not manage it Milestones People Productivity Mistakes Time to fix mistakes Etc.

2015

Why Requirements Engineering? Von Neumann: “There is no sense in being precise when you don’t even know what you are talking about”

Context The Blank Page Fallacy The Completeness Fallacy Social Aspects Involved

So, What are Requirements? Clients Users Needs Limitations Impossibilities Technological Infra-Structure

Definition Software Requirements Sentences that express clients’ needs and establish the desired quality

Types of Requirements Functional Requirements FR are the requirements that are directly related to the software functionality. What the system must do ! Non-Functional Requirements NFRs express constraints that a software must comply with. Can be seen as specific qualities that a software must have “How” the software must do the “What” Ex: Safety, accuracy, usability, security Requirements-1 (Inverse Requirements) IR establish conditions that must never happen Frequently associated to an NFR

After all, What are Requirement? Clients FR Users Needs Limitations Impossibilities NFR NFR IR Technological Infra-Structure

Examples The system should provide a form to enter results for clinical tests performed for a client (FR) Depending on the result of the test, only the Supervisor can entry the result for this patient. E.g. Glucose over 8.0 (NFR Safety) The system should give the client a receipt. This should take no longer than 8 sec (FR “.” NFR Performance) The system can not erase any client information (IN)

Definitions Universe of Discourse Is the context in which the software should be developed and operated. UofD includes all sources of information and all people related to the software. These people are also known as the actors of this universe. UofD is a reality circumstantiated by the set of goals defined by those who demand the software

Information Systems Universe of Discourse Macrosystem Software System

organization hardware Information System software

An SADT Model for the Definition of Requirements UofD Select Personel Soft. Eng. Viewpoints clients method UofD Elicit facts Model requirements model UofD Analyse Select Method tools

The “Requirements Lifecycle” Not Waterfall Not Spiral Not Iterative

Books Requirements Engineering: Processes and Techniques by Ian Sommerville, Gerald Kotonya (September 1998) John Wiley & Son Ltd; ISBN: 0471972088 Amazon.com Sales Rank: 188,502 System Requirements Engineering by Pericles Loucopoulos, Vassilios Karakostas (June 1995) McGraw Hill Text; ISBN: 0077078438 Amazon.com Sales Rank: 1,067,908 Software Requirements & Specifications : A Lexicon of Practice, Principles and Prejudices by Michael Jackson (July 1995) Addison-Wesley Pub Co; ISBN: 0201877120 Amazon.com Sales Rank: 38,607

More Books Exploring Requirements : Quality Before Design by Donald C. Gause and Gerald M. Weinberg (September 1989) Dorset House; ISBN: 0932633137 Amazon.com Sales Rank: 13,641 Mastering the Requirements Process by Suzanne Robertson, James Robertson (May 4, 2000) Addison-Wesley Pub Co; ISBN: 0201360462 ; Dimensions (in inches): 0.93 x 9.50 x 7.66 Amazon.com Sales Rank: 7,392 Managing Software Requirements: A Unified Approach (The Addison- Wesley Object Technology Series)by Dean Leffingwell, Don Widrig (November 1999),Addison-Wesley Pub Co; ISBN: 0201615932 Dimensions (in Inches): 1.13 x 9.46 x 7.76 Amazon.com Sales Rank: 14,447

Reading for next Class Requirements Engineering - a roadmap - Nuseibeh, Easterbrook – First Presentation [Goguen94] - Goguen, J.A. and Linde, C. - Techiques for Requirements Elicitation, In   Proceedings of the First IEEE International Symposium on Requirements Engineering, San Diego, Ca, IEEE Computer Society Press - 1994,  pp 152-164.  [Goguen94a] - Goguen, Joseph - Requirements Engineering as the reconciliation of social and technical issues - in Requirements Engineering: Social and Technical Issues edited by Joseph Goguen and Marina Jirotka - Academic Press 1994. Download from course page