COMP1007 Introduction to Requirements Analysis Module Leader: Dr Pam Watt

COMP1007 Introduction to Requirements Analysis  1 lecture  1 lab (start week 3)  1 tutorial (start week 2)  Assignment (50%)  Exam (50%)  Set Text: Requirements Analysis & System Design. Developing Information Systems with UML Leszek A Maciaszek Publ. Addison Wesley

COMP1007 Introduction to Requirements Analysis Software Process COMP1007 Lecture 1

COMP1007 Introduction to Requirements Analysis Objectives  Software Development  System Planning  Lifecycle  Software Development Approaches

COMP1007 Introduction to Requirements Analysis Software Development  Stakeholders  Process  Modelling language & tools

COMP1007 Introduction to Requirements Analysis Software Development  Commercial off-the-shelf packages  Bespoke systems

COMP1007 Introduction to Requirements Analysis Stakeholders  Customers -person paying -responsible for decisions -customer’s requirements  Developers -developed by people, for people -social factors important

COMP1007 Introduction to Requirements Analysis Software Failure  needs misunderstood or not captured  requirements change too frequently  insufficient resources for the project  customers don’t co-operate with developers  unrealistic expectations  system no longer of benefit to customer

COMP1007 Introduction to Requirements Analysis  hire the best developers  provide on-going training & education  encourage exchange of information & interaction  motivate developers  remove obstacles to development  offer an exciting work environment  align personal goals  emphasise teamwork

COMP1007 Introduction to Requirements Analysis Process A process model:  states order of activities  specifies development artefacts  assigns activities & artefacts to developers  monitors project progress  Quality standards

COMP1007 Introduction to Requirements Analysis Modelling Languages & Tools  Modelling artefacts have to be communicated  Developers need a language to build visual models - communicate WHAT needs done  Need a tool for CASE

COMP1007 Introduction to Requirements Analysis CASE Tools  co-ordinate access to models  facilitate collaboration  version control  share components  check consistency & integrity  generate project reports  generate data structures & code  reverse engineer

COMP1007 Introduction to Requirements Analysis Unified Modelling Language  general purpose visual modelling language  independent of s/ware development process  matches up with RUP  independent of implementation technologies  models static structures & dynamic behaviour

COMP1007 Introduction to Requirements Analysis UML cont. catagorised in to 3 groups:  State Models - static data structures  Behaviour Models - object collaborations  State Change Models - describe permitted states

COMP1007 Introduction to Requirements Analysis System Planning SWOT –Strengths, Weaknesses, Opportunities, Threats VCM –Value Chain Model BPR –Business Process Re-engineering ISA –Information Systems Architecture

COMP1007 Introduction to Requirements Analysis Software Lifecycles  Orderly set of activities  Phases –analysis –design –implementation

COMP1007 Introduction to Requirements Analysis Analysis Phase  Concentrates on system requirements - determined & specified  Functional & non-functional requirements

COMP1007 Introduction to Requirements Analysis Design Phase  Architectural design  Detailed design

COMP1007 Introduction to Requirements Analysis Implementation Phase  Coding & s/ware development  Testing  Changeover

COMP1007 Introduction to Requirements Analysis Lifecycle Phases  Requirements determination  Requirements Specification  Architectural Design  Detailed Design  Implementation  Integration  Maintenance Planning & testing span the whole lifecycle

COMP1007 Introduction to Requirements Analysis Requirements Determination “A statement of system service or constraint” Kotonya & Sommerville  Determine requirements  Analyse requirements  Negotiate requirements

COMP1007 Introduction to Requirements Analysis Requirements Specification Phase  Model requirements  Include non-functional requirements  Independent from h/ware & s/ware platforms

COMP1007 Introduction to Requirements Analysis Architectural Design Phase  Contract between developer & customer  Description of system - in terms of its modules  Platform specific  Three-tier architecture

COMP1007 Introduction to Requirements Analysis Detailed Design Phase  Describes each module in detail  User interface design  Database design etc.

COMP1007 Introduction to Requirements Analysis Implementation Phase  Installation of purchased s/ware  Coding of custom-written s/ware  Loading of test databases  Testing  User training  Hardware issues

COMP1007 Introduction to Requirements Analysis Maintenance Phase 3 distinct phases:  Housekeeping  Adaptive maintenance  Perfective maintenance  Phased out

COMP1007 Introduction to Requirements Analysis Software Development Approaches  Structured - function centric  Object Orientated - data centric

COMP1007 Introduction to Requirements Analysis References  Maciaszek, Requirements Analysis & System Design, Chp 1  Bennett, McRobb & Farmer, OO Systems Analysis & Design  Schah (1996) Classical and Object- Orientated Software Engineering, 3 rd ed, Irwin pp604