CIS 302 Introduction To Systems Analysis and Design

1
CIS 302Introduction To Systems Analysis and
Design

• The Systems Development Environment

1.1
2
Learning Objectives

• Define information systems analysis and design
• Discuss the modern approach to systems analysis
  and design
• Describe the organizational role of the systems
  analyst

1.2
3
Learning Objectives

• Describe four types of information systems
• Transaction Processing Systems (TPS)
• Management Information Systems (MIS)
• Decision Support Systems (DSS)
• Expert Systems (ES)
• Describe the information systems development life
  cycle (SDLC)

1.3
4
Learning Objectives

• Discuss alternatives to the systems development
  life cycle
• Discuss the role of computer aided software
  engineering (CASE) tools in systems development

1.4
5
Overview

• Systems Analysis is a proven method to help
  business utilize information to its fullest
• Systems Development Life Cycle (SDLC)
• Central to Information Systems Development

1.5
6
Information Systems Analysis and Design

• A method used by companies to create and maintain
  systems that perform basic business functions
• Main goal is to improve employee efficiency by
  applying software solutions to key business tasks
• A structured approach must be used in order to
  ensure success

1.7
7
Information Systems Analysis and Design

• Systems Analyst performs analysis and design
  based upon
• Understanding of organizations objectives,
  structure and processes
• Knowledge of how to exploit information
  technology for advantage

1.8
8
Systems Analysis and Design Core Concepts

• Major goal to improve organizational systems by
  developing or acquiring software and training
  employees in its use
• Application software, or a system, supports
  organizational functions or processes

1.9
9
Systems Analysis and Design Core Concepts

• System Turns data into information and includes
• Hardware and system software
• Documentation and training materials
• Job roles associated with the system
• Controls to prevent theft or fraud
• The people who use the software to perform their
  jobs

1.10
10
Software Engineering Process

• A process used to create an information system
• Consists of
• Methodologies
• A sequence of step-by-step approaches that help
  develop the information system
• Techniques
• Processes that the analyst follows to ensure
  thorough, complete and comprehensive analysis and
  design
• Tools
• Computer programs that aid in applying techniques

1.11
11
System

• A system is an interrelated set of business
  procedures used within one business unit working
  together for a purpose
• A system has nine characteristics
• A system exists within an environment
• A boundary separates a system from its environment

1.12
12
Characteristics of a System

• Components
• Interrelated Components
• Boundary
• Purpose
• Environment
• Interfaces
• Constraints
• Input
• Output

1.13
13
Important System Concepts

• Decomposition
• The process of breaking down a system into
  smaller components
• Allows the systems analyst to
• Break a system into small, manageable subsystems
• Focus on one area at a time
• Concentrate on component pertinent to one group
  of users
• Build different components at independent times

1.14
14
Important System Concepts

• Modularity
• Process of dividing a system into modules of a
  relatively uniform size
• Modules simplify system design
• Coupling
• Subsystems that are dependent upon each other are
  coupled
• Cohesion
• Extent to which a subsystem performs a single
  function

1.14
15
A Modern Approach to Systems Analysis and Design

• Systems Integration
• Allows hardware and software from different
  vendors to work together.
• Enables procedural language systems to work with
  visual programming systems
• Visual programming environment uses client/server
  model

1.15
16
Data and Processes

• Three key components of an information system
• Data
• Data Flows
• Processing Logic
• Data vs. Information
• Data
• Raw facts
• Information
• Derived from data
• Organized in a manner that humans can
• understand.

1.16
17
Data and Processes

• Data
• Understanding the source and use of data is key
  to good system design
• Various techniques are used to describe data and
  the relationship amongst data
• Data Flows
• Groups of data that move and flow through the
  system

1.17
18
Data and Processes

• Data Flows (Continued)
• Include description of sources and destination
  for each data flow
• Processing Logic
• Describe steps that transform data and events
  that trigger the steps

1.18
19
Approaches to Systems Development

• Process-Oriented Approach
• Focus is on flow, use and transformation of data
  in an information system
• Involves creating graphical representations such
  as data flow diagrams and charts
• Data are tracked from sources, through
  intermediate steps and to final destinations
• Natural structure of data is not specified
• Disadvantage data files are tied to specific
  applications

1.19
20
Approaches to Systems Development

• Data-Oriented Approach
• Depicts ideal organization of data, independent
  of where and how data are used
• Data model describes kinds of data and business
  relationships among the data
• Business rules depict how organization captures
  and processes the data

1.20
21
Databases and Application Independence

• Database
• Shared collection of logically related data
• Organized to facilitate capture, storage and
  retrieval by multiple users
• Centrally managed
• Designed around subjects
• Customers
• Suppliers
• Application Independence
• Separation of data and definition of data from
  applications

1.21
22
Role of the Systems Analyst

• Study problems and needs of an organization
• Determine best approach to improving organization
  through use of
• People
• Methods
• Information technology
• Help system users and managers define their
  requirements for new or enhanced systems

1.22
23
Role of the Systems Analyst

• Assess options for system implementation
• In-house development
• Outsourced development
• Outsourced development and operation
• Commercial application
• For in-house projects, work on a team of analysts
  and developers

1.23
24
Skills of a Successful Systems Analyst

• Analytical
• Understanding of organizations.
• Problem solving skills
• System thinking
• Ability to see organizations and information
  systems as systems
• Technical
• Understanding of potential and limitations of
  technology.

1.24
25
Skills of a Successful Systems Analyst

• Managerial
• Ability to manage projects, resources, risk and
  change
• Interpersonal
• Effective written and oral communication skills

1.25
26
Types of Information Systemsand Systems
Development

• Transaction Processing Systems (TPS)
• Automate handling of data about business
  activities (transactions)
• Management Information Systems (MIS)
• Converts raw data from transaction processing
  system into meaningful form
• Decision Support Systems (DSS)
• Designed to help decision makers
• Provides interactive environment for decision
  making

1.26
27
Types of Information Systemsand Systems
Development

• Expert Systems (ES)
• Replicates decision making process
• Knowledge representation describes the way an
  expert would approach the problem

1.27
28
Systems Development Life Cycle

• System Development Methodology
• Standard process followed in an organization
• Consists of
• Analysis
• Design
• Implementation
• Maintenance

1.28
29
Systems Development Life Cycle

• Series of steps used to manage the phases of
  development for an information system
• Consists of four phases
• Planning and Selection
• Analysis
• Design
• Implementation and Operation

1.29
30
Systems Development Life Cycle

• Phases are not necessarily sequential
• Each phase has a specific outcome and deliverable
• Individual companies use customized life cycle

1.30
31
Phases of the Systems Development Life Cycle

• Systems Planning and Selection
• Two Main Activities
• Identification of need
• Investigation and determination of scope
• Systems Analysis
• Study of current procedures and information
  systems
• Determine requirements
• Generate alternative designs
• Compare alternatives
• Recommend best alternative

1.31
32
Systems Development Life Cycle

• System Design
• Logical Design
• Concentrates on business aspects of the system
• Physical Design
• Technical specifications
• Implementation and Operation
• Implementation
• Hardware and software installation
• Programming
• User Training
• Documentation

1.32
33
Systems Development Life Cycle

• Operation
• System changed to reflect changing conditions.
• System obsolescence

1.33
34
Approaches to Development

• Prototyping
• Building a scaled-down working version of the
  system
• Advantages
• Users are involved in design
• Captures requirements in concrete form
• Rapid Application Development (RAD)
• Utilizes prototyping to delay producing system
  design until after user requirements are clear

1.34
35
Approaches to Development

• Joint Application Design (JAD)
• Users, Managers and Analysts work together for
  several days
• System requirements are reviewed
• Structured meetings

1.35
36
Summary

• Information systems analysis and design
• Process of developing and maintaining an
  information system
• Modern approach to systems analysis
• Process-Oriented
• Data-Oriented

1.36
37
Summary

• Role of Systems Analyst
• Four types of information systems
• Transaction Processing (TPS)
• MIS
• Decision Support (DSS)
• Expert Systems (ES)

1.37
38
Summary

• Systems Development Life Cycle (SDLC)
• Systems Planning and Selection
• Systems Analysis
• Systems Design
• Systems Implementation
• Alternatives to Systems Development Life Cycle
• Prototyping
• Rapid Application Development (RAD)
• Joint Application Design (JAD)

1.38
39

• (Break)
• INFORMATION SYSTEMS DEVELOPMENT
• THE SYSTEMS DEVELOPMENT LIFECYCLE (SDLC)

40
Lecture Objectives

• to understand the information systems
  problem-solving process
• to be aware of the main phases of the systems
  development lifecycle

41
Business Information System Problems and
Opportunities

• The need to build new information systems or
  change existing ones comes about because
• there are problems in the way in which existing
  systems operate
• or
• changes in circumstances create opportunities to
  improve things by doing them differently
• or
• new functions or activities are to be undertaken

42
Business Information Processing Problems

• Information problems occur when an organisations
  systems fail to meet its information and
  processing needs adequately.
• Some causes
• changing information needs
• business expansion
• cost pressures
• competitive pressures
• new business activities
• inefficiencies
• Information processing problems can occur at any
  stage of the information processing cycle

43
Business Information Processing Problems

• Characteristics
• complex -
• the number and variety of components and their
  interactions
• non-standard -
• many organisations have similar needs, but
  rarely are these identical
• solutions must be customised for specific
  circumstances
• unstructured -
• problems cannot easily be broken down into
  clearly-defined components with easily-identified
  connections between them

44
How do you solve problems?

• The Intuitive Approach
• versus
• The Scientific Approach

45
Intuitive Problem-solving

• I don't have to think about how to solve the
  problem I just do it
• No conscious reasoning process or planning
  involved
• Use accumulated knowledge/understanding/
  judgement/heuristics (i.e. rules of thumb), but
  do not make them explicit
• The most commonly used approach for every day
  problem-solving

46
'Scientific' Problem-solving

• Identify that there is a problem and describe it
• Analyse the problem and specify what needs to be
  done to fix it
• Identify the potential courses of action which
  may fix the problem
• Evaluate them and choose the best one
• Describe in detail the chosen course of action
• Put the chosen course of action into effect
• Evaluate the outcome of the chosen course of
  action and check that it has fixed the problem

47
Which Approach to Use?

• Depends on
• nature of the problem
• complexity of the problem
• degree of standardisation of the problem
• experience in solving this kind of problem
• extent to which the problem can be structured
  into small self-contained parts

48
Approaches to information systems development

• early computer information systems development
  focused on technology, programming and technical
  skills
• systems developers were technically trained and
  skilled, and used rule-of-thumb and personal
  experience as the basis for developing systems
• as computer use became more widespread, a backlog
  of computer application requests developed,
  existing applications increasingly required
  changes, and changes made tended to have
  unexpected and undesirable effects
• these problems led to awareness of the need for
  an overall accepted, standardised approach to
  system development

49
The Process of System Development

• There is no 'universal' problem-solving process
  which can meet the needs of all system
  development situations
• Approaches to developing information systems to
  solve business information processing problems
  must be tailored to meet the needs of the
  situation
• Some elements of the system development process
  can be 'standardised' to some degree

50
The Systems Development Lifecycle (SDLC)

• The concept of the systems development life
  cycle (SDLC) is an attempt at achieving this
  standardisation. It provides
• a systematic and orderly approach to solving
  business information and processing problems
• a means of managing, directing, monitoring and
  controlling the process of system building,
  including
• a description of the process - steps to be
  followed
• deliverables - reports/programs/documentation/etc
• milestones - dates of completion of steps or
  deliverables
  

51
The Systems Development Lifecycle

• it has several phases that define the progress of
  the development process
• it is often adapted to suit the organisational,
  human and technical needs of organisations and
  system development projects
• there are many variants of the SDLC
• traditional waterfall or linear model,
  iterative model, spiral model etc.
• we will consider the traditional waterfall model
  first

52
Benefits of SDLC

• breaks the problem-solving process into
  manageable steps
• identifies and defines everything which needs to
  be done, and how it should be done
• identifies the resources needed in each step
• identifies who will do each activity and when
  they will do it
• provides a basis for project planning

53
Principles ofSystem Development

• get the owners and users involved
• use a problem-solving approach
• establish phases and activities
• establish standards for consistent development
  and documentation
• justify systems as capital investments
• dont be afraid to cancel or revise project scope
• divide and conquer
• design systems for growth and change

54
Systems Development Phases
Analysts Role
Initiation
Analysis
Design
Implementation
Quality
Documentation
Review
Ethics
Project Management
Maintenance
55
Initiation (Why?)

• Is this project worth doing?

System Users
Planned development project
Unplanned development project
Steering Committee
Survey Project Feasibility
Feasibility Report (scope defined)
Problem/opportunity details
Constraints
ANALYSIS
System Owners
56
Initiation

• a preliminary investigation of the problems,
  opportunities, constraints and available
  resources in order to decide on a course of
  action
• enhance existing system?
• develop a new information system?
• do nothing .. add it to the backlog?
• define the system scope the functions/activities
  which are to be developed/redeveloped
• poor scope management often results in
  unsuccessful systems

57
Initiation

• Defining the project scope includes identifying
• key stakeholder groups
• perceived problems and opportunities
• constraints
• possible solutions client expectations
• Key deliverable is a feasibility report
• Includes overview of proposed solutions with
  cost/benefit analyses for each solution

58
Analysis (What?)

• Define the clients requirements (What?)

System Users
INITIATION
Feasibility Report
Problem/opportunity details
Analyse the problem and define requirements
System Requirements Specification Report
System Requirements Specification Report
DESIGN
System Owners
59
Analysis

• Dont try to fix it unless you understand it
• Study the existing system to thoroughly
  understand the problems and opportunities
• Review findings with clients and revise scope if
  necessary
• Clearly define WHAT the new system must do
• Agree on acceptance criteria for the new system
  (signoff on the system specification)
• should the system specification be frozen?
• Assess feasibility again

60
Design (How?)

• Define how the system will be implemented

Various Sources
System Requirements Specification Report
ANALYSIS
Design ideas/opinions
Select a design strategy and specify details
Design Options
System Vendors
Hardware/Software deals
Selected Design Option
Design in Progress Report
Technical Design Report
SystemOwners/Users
IMPLEMENTATION
61
Design

• Generate a number of design options based on
  technical, operational, economic, scheduling and
  tendering constraints (HOW?)
• The client selects the best option for their
  needs (assess feasibility again)
• Acquire the necessary hardware and software
• Design interfaces, databases, networks as
  required
• Specify integration requirements and software
  requirements (programs)

62
Implementation (Build)
System Users

• Build and deliver the system

User acceptance testing
Technical Design Report
DESIGN
User Documentation
Build, test, install and deliver the new system
User Training
System Vendors
Hardware/ Software
Production System
System and Technical Documentation
System Owners
Project Report
MAINTENANCE
63
Implementation

• Build/modify databases and networks as required
• Build and test programs
• Prepare users for new system
• acceptance testing, user documentation, user
  training, maintenance procedures
• Finalise system and technical documentation
• Install the system

64
Review
System Users

• What went wrong/right? Why?

System Audit Report
Problems/New ideas
Review the system and the project
Auditor
Project issues and system bugs
Fixes and enhancements
MAINTENANCE
Project Review Report
Steering Committee
Project staff
65
Review

• How well were the system and project objectives
  met?
• Clients requirements met, within budget, on
  time?
• Can further benefits be realised?
• Are major changes required?
• How successful was the development process ..
  what can we learn?
• Review the maintenance effort

66
Maintenance
System Users

• Fix it / Make it better

Fixes and enhancements
Problems/New ideas
Maintain the new system
Additional training and documentation
Technical problems and new technology
Modifications
Escalating maintenance
Project staff
PRODUCTION SYSTEM
back to INITIATION
67
Maintenance

• Corrective - fix errors
• Adaptive - satisfy changing needs
• Perfective - enhance performance
• Preventative - fix potential problems
• If the cost of maintenance is too high consider
  other options
• new development, purchase a software package,
  re-engineer/modify

68
Systems Development Cross Life Cycle Activities

• Cross Life Cycle Activities are those which
  overlap many or all of the life cycle phases.
  Some of these are
• Quality - must be embedded in the process of
  systems development to achieve a quality outcome
• Project Management - to monitor and control the
  project and ensure it stays on track
• Documentation - essential at every stage to help
  ensure project and system viability
• Ethics - voluntary compliance with guidelines of
  IS/IT professional societies

69
Quality

• Quality is defined as fitness for purpose and
  concerns both process and product.
• Error detection and correction in analysis and
  design is much cheaper than after the system is
  implemented.
• Achieving quality requires that organisational
  structures, responsibilities, procedures,
  processes and resources for implementing quality
  management are in place.

70
Project management

• Select systems development methodology
• Plan the project tasks
• Estimate the resources and time required to
  complete individual phases of the project
• Staff the project team
• Organise and schedule the project
  effort(tasks/time/ people/technical resources)
  and therefore cost
• Control the project development
• direct the team, monitor progress, replan,
  restaff, reallocate resources

71
Documentation

• Various types of documentation must be produced
  throughout the SDLC
• The data dictionary plays an important role
  during and after systems development
• A repository for information about and
  definitions of all objects identified during
  development
• It supports and is maintained throughout the
  system lifecycle
• It provides an important source for system
  documentation

72
Professional ethics

• Australian Computer Society (ACS)
• Code of Ethics for IT professionals
• your reputation
• your client's interests
• confidentiality
• the clients own and their competitors'
• impartiality
• honesty

73
Systems DevelopmentThe systems developers
skills

• Systems developers require many different skills
  during the SDLC. Some of these are
• Interpersonal skills - to communicate
  effectively, facilitate groups, work in teams,
  manage expectations and change, deal with
  organisational politics
• Analytical skills - to identify problems and
  determine solutions
• Business knowledge - understanding of business
  systems
• Technical skills and knowledge - to use the
  technology, and understand its potential and
  limitations
• Management skills - to manage resources,
  projects, risk, and organisational change

74
Some Approaches to Systems Development

• There are many different approaches to developing
  systems depending on the nature of the systems
  and the users needs. Some of these are
• Traditional Waterfall SDLC- formal approach which
  partitions development into distinct phases
• Prototyping - an iterative process of building an
  experimental system rapidly
• Application Packages - purchase commercially
  available software

75
Some Approaches to Systems Development

• Joint Application Development (JAD) - a workshop
  approach in which a facilitator, users, managers
  and developers work intensively together over a
  short period (days) to specify requirements and
  design a system
• Participatory Design (PD) - where the central
  focus is the users participating actively in
  system development
• RAD - rapid application development using
  techniques to build systems quickly where
  appropriate

76
Who does Systems Development?

• The organisartions information technology
  department
• (in-house development)
• End-user computing - development of systems by
  end-users with minimal assistance
• Outsourcing - contracting development to external
  providers
• IT consultants
• Often a combination of the above

77
There is no such thing as a 'correct,'standard'
development lifecycle approach to system
development , because all information and
processingproblems are different and need
differentsystem development approaches.
Summary