Information Systems 1
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Transcript Information Systems 1
IMS9001 - Systems Analysis and Design
INTRODUCTION:
INFORMATION SYSTEMS
DEVELOPMENT,
THE SYSTEMS DEVELOPMENT
LIFECYCLE (SDLC)
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Teaching Staff
Lecturer:
Caulfield day:
Dr. Peta Darke
Room S7.13 - Level 7, Chisholm Tower
email - [email protected]
telephone - 9903 2416
Make sure you obtain your tutor’s contact details and the
location and times your tutor is available for student
consultation
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Unit Information
All unit materials:
lecture notes, tutorials, assignments, notices at
www.sims.monash.edu.au/subjects/IMS9001.nsf
No tutorials this week
Assessment:
exam - 50%, assignment - 50%
a pass requires a final mark of 50% or more
hurdle - you must earn a minimum of 40% for the exam
AND a minimum of 40% for the assignments
If either hurdle is not met, a result of 44 marks will be
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recorded even if the total mark is > 50
A System
An assembly of components that interact
in an organised way to accomplish goals
system elements
a boundary, a purpose, an environment,
interfaces, inputs, processes, outputs,
feedback, constraints, subsystems
E.g. natural systems: river systems, mountain
systems, solar system, respiratory system,
nervous system
artificial or man-made systems: computer,
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legal, education, information systems
Information Systems
An information system is a “formal”
arrangement of people, data and processes
integrated to to manage complexity and
support and improve business operations
and the problem-solving and decisionmaking activities of managers.
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Data vs. Information
Data - consists of raw or unstructured facts
(text, pictures, sound)
eg. Student number, Course code
Information - data that is interpreted:
a collection of facts organised so that they
have meaning and use to a particular
recipient in a particular context,
additional value beyond the value of the
facts themselves
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Functions of an
Information System
Any information system performs four main
functions:
data input - recording information
data storage/retrieval - keeping information
data processing - transforming information
data output - displaying/presenting information
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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
AND/ OR
changes in circumstances create opportunities to
improve things by doing them differently
AND/ OR
new functions or activities are to be undertaken
e.g.
changing information needs, business expansion,
cost pressures,competitive pressures,
new business activities, inefficiencies
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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
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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
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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
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The Systems Development
Lifecycle (SDLC)
it has several phases that define the progress
of the development process
it can be 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.
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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
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Guidelines for
System 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
don’t be afraid to cancel or revise project scope
divide and conquer
design systems for growth and change
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Systems Development Phases
Analysts Role
Initiation
Analysis
Design
Implementation
Documentation
Review
Ethics
Project Management
Maintenance
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Initiation (Why?)
Is this project worth doing?
System
Users
Planned development project
Steering Committee
Survey Project
Feasibility
Feasibility
Report
(scope
defined)
Constraints
Unplanned
development
project
Problem/opportunity
details
ANALYSIS
System Owners
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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
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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
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Analysis (What?)
Define the client’s requirements (What?)
INITIATION
System
Users
Feasibility Report
Problem/opportunity
details
System
Requirements
Specification Report
Analyse the problem
and define
requirements
System Requirements
Specification Report
DESIGN
System Owners
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Analysis
“Don’t 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
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Design (How?)
Define how the system will be implemented
ANALYSIS
System
Vendors
System
Requirements
Specification Report
Hardware/Software
deals
Various
Sources
Design
ideas/opinions
Select a design
strategy and specify
details
Technical Design
Report
Design Options
Selected Design
Option
Design in Progress
Report
IMPLEMENTATION
SystemOwners/
Users
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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)
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Implementation (Build)
System
Users
Build and deliver the system
DESIGN
User acceptance
testing
Technical
Design Report
User Documentation
System
Vendors
Hardware/
Software
Build, test, install
and deliver the
new system
User Training
Production System
System and
Technical
Documentation
MAINTENANCE
Project Report
System Owners
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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
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Review
System
Users
What went wrong/right? Why?
System Audit Report
Problems/New ideas
Auditor
Fixes and
enhancements
Review the
system and the
project
MAINTENANCE
Project issues and
system bugs
Project
Review Report
Steering Committee
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Review
How well were the system and project
objectives met?
Client’s 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
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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
Project staff
Escalating
maintenance
back to INITIATION
Modifications
PRODUCTION SYSTEM
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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
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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
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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.
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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
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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
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documentation
Professional ethics
Australian Computer Society (ACS)
Code of Ethics for IT professionals
your reputation
your client's interests
confidentiality
the client’s own and their competitors'
impartiality
honesty
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Systems Development:
The systems developer’s 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
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Building Information Systems:
The Role of the Systems Analyst
To understand the business’s information needs
what information is needed?
for whom?
in what form?
when?
To describe the business’s information flows
To identify problems and opportunities
To suggest possible system solutions
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Analysis and Design in the SDLC
Compare with the role of an architect in building a
house
Analysis - finding out WHAT the client needs
Design - deciding HOW to meet these needs
Distinction between the two is not always as clear in
practice as it sounds in theory as they tend to
merge in practice (compare architect’s role)
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The Role of the Systems Analyst
A systems analyst needs to be able to relate well to
a wide range of different sorts of people:
business management
system users and owners
technical people (programmers, database programmers,
systems administrators, operations staff, data communications
and network specialists
consultants
vendors
Critical Systems Thinking (CST), problem solving,
communication, business and IT skills
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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
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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
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Who does Systems
Development?
The organisartion’s 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
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References
HOFFER, J.A., GEORGE, J.F. and VALACICH (2005) Modern
Systems Analysis and Design, (4th edition), Pearson
Education Inc., Upper Saddle River, New Jersey, USA. Chapter
1, Appendix 1
WHITTEN, J.L., BENTLEY, L.D. and DITTMAN, K.C. (2001) 5th
ed., Systems Analysis and Design Methods, Irwin/McGraw-HilI,
New York, NY. Chapters 1,3,4
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