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8/11/2019 Developing Information System Solution
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Developing information system solution
system development life cycle
1. Investigation
2. Analysis
3. Design4. Coding
5. Testing
6. Implementation7. Maintenance
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System Investigation
Product:Feasibility study
System AnalysisProduct:Functional Requirements
System Maintenance
Product:Improved System
System ImplementationProduct:Operational System
System DesignProduct:System Specification
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System development life cycle
Understand the
Business Problem or
opportunity
Develop anInformation System
Solution
Implement the
Information System
solution
Determine whether a business problem or
opportunity exists
Conduct a feasibility study to determine whether a
new or improved information system is a feasible
solution
Develop a project management approval
Analyze the information needs of end users,the
organizational environment and any systempresently used
Develop the functional requirements of a system
that can meet the needs of end users
Develop specifications for the
hardware,software,people,network, and data
resources, and the information products that will
satisfy the functional requirements of the Proposed
system
Acquire(or develop)hardware and software.
Test the system and train people to operate and
use it.
Convert to the new system.
Use a post implementation review process to
monitor, evaluate,and modify the system as needed
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SYSTEM INVESTIGATION
Determine whether a business problem or
opportunity exists
Conduct a feasibility study to determine
whether a new or improved information
system is a feasible solution
Develop a project management approval
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SYSTEM ANALYSIS
Analyze the information needs of end
users,the organizational environment
and any system presently usedDevelop the functional requirements
of a system that can meet the needs
of end users
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SYSTEM DESIGN
Develop specifications for the
hardware,software,people,networ
k, and data resources, and theinformation products that will
satisfy the functional
requirements of the Proposed
system
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System Implementation
Acquire(or develop)hardware and
software.
Test the system and train peopleto operate and use it.
Convert to the new system.
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SYSTEM MAINTENANCE
Use a post implementation
review process to monitor,
evaluate,and modify the
system as needed
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Feasibility Study
A feasibility study is a preliminary studywhich investigates the information needsof prospective users and determines the
resource requirements,costs,benefits andfeasibility of a proposed system.
The goals of feasibility studies is toevaluate alternative systems and topropose the most feasible and desirablesystems for development
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Way to gather information for
system development Interviews with employees,customers,and
managers
Questionnaires to appropriate users in the
organization Personal observation ,videotaping,or
involvement in end user work activities.
Examination ofdocuments,reports,proceduresmannuals,and other documentation
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Types of Feasibility study
Organizational Feasibility
Technical Feasibility Economic Feasibilty
Operational Feasibility
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Organizational Feasibility
How well the proposed
system supports thestrategic objectives of
the organisation
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Technical Feasibility
To study the capability,reliability,and
availability of of hardware,software,and
network
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Economic Feasibility
Costs Savings
Increased revenue
Decreased investment Increased profits
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Operational feasibility
End user Acceptance
Management support
Customer,supplier, and governmentrequirements
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Cost/Benefit Analysis
Feasibility studies typically involves
cost/benefit analysis
Tangible cost & intangible cost
Tangible benefits & Intangible Benefits
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Tangible cost
The costs and benefits which could be
quantified is called tangible.
Examples are
Cost of H/W, S/W, salaries and other
expenses that can be quantified.
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Intangible Costs
The events/transaction etc which can not
be quantified .
Examples
Customer goodwill
Employee morale
Attitude
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Tangible Benefits and Intangible
Benefits
Tangible benefits are favorable results,such as the decreased in payroll costscaused by a reduction in Personnel or a
decrease in inventory carrying costscaused by a reduction in inventory.
Intangible benefits arte harder toestimate.Such benefits as better customerservice or faster and more accurateinformation for management fall into thiscategory
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Examples of Tangible/ Intangible Benefits
Tangible benefits
Increase in sales orprofits
Decrease ininformation
processing costs Decrease in
operating cost
Decrease in
required investment
Increasedoperational abilityand efficiency
Examples
Development ofcomputer_based products
and services.
Elimination of unnecessary
procedures and documents
Reduction in inventorycarrying costs.
Decrease in inventory
investment required
Improvement in production
ability and efficiency forexample,less
spoilage,waste,and idle
time.
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Intangible Benefits New or improved
information availability
Improved abilities in
computation and
analysis
Improved customer
service
Improved management
decision making
Improved competitive
position
Improved business and
community image
Example
More timely and accurateinformation and new types of
information
Analytical modeling
More timely service
response
Elimination of burdensome
boring job tasks
Better information and
decision analysis
Systems which lock in
customers and suppliers
Progressive image as
perceived by
customers,suppliers andinvestors
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System Analysis
It is an in-depth study of end user informationneeds that produces functional requirementsthat are used as the basis for the design of anew information system
It is a detailed study of:The information needs of the organization and
end users
The activities,resources,and procedures of any
present information systemsThe information system capabilities required to
meet your information needs,and those ofother end users.
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Activities associated in System
Analysis Organizational Analysis
Analysis of the Present System
Functional Requirements Analysis
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Organizational Analysis
It is the first step in system analysis.
Before developing the new system the
developer have to know about the
organization like its management
structure,its people,its business
activities,the environmental systems and
its current information systems.
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Analysis of the present system
Before designing a new system,it is important to
study the existing system which has to be
replace
It is needed to analyze how this system useshardware,software,network,and other resources
to convert data resources,such as transactions
data,into information products,like reports and
displays.
After that the developer can find out the
input,processing,output,storage and control for
the proposed system.
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Functional Requirements
Analysis Functional requirements specify
information system capabilities required tomeet the information needs of users.
The key areas where the functionalrequirements should be developed are
User interface requirements
Processing requirementsStorage requirements
Control requirements
ypes o unc ona
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ypes o unc onaRequirements
User interfacerequirements:Theinput /output needs of
end users that mustbe supported byinformationsystem,includingsources,formats,content,volume,andfrequency of eachtype of input andoutput
Processing
requirements:Activities required to convert
input to output.Includes
calculations,decision
rules,and other
processing
operations,and
capacity,throughput,turnaround time,and response
time needed for
processing activities.
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Types of Functional
Requirements Storage
Requirements
Organization,content
size of databases ,types and frequency
of updating and
inquires, and the
length and rationalefor record retention.
Control
requirements
Accuracy,validity,
safety,security,andadaptability
requirements for
system
input,processing,output,and
storage functions.
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System Design
This phase starts after the system analysis
phase is over
In other word the output of the system analysis
phase,is the input for the design phase Data requirements are worked out on the basis
of user requirement estimates.
The identification of data requirements includesidentifying data sources,the nature and type of
data that are available and data gaps if any.
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Objectives of Design
1. Practicality
user-friendly2. Flexibility the system must be responsive
3. Efficiency
* Through put
* Response Time
* Run Time
4. Security-This aspect relates to H/W
reliability,physical security of data and thedetection and prevention of fraud and abuse
of data.
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Stages in system design
It consists of three activities:
1. User Interface Keep it simple
Keep it clean
Organize logically
2. Data Design
3. Process Design
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Problems in System Design
Problem of scale
Problem of quality
Problem of productivity Problem of Cost
Problem of scheduling
Problem of consistency
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Coding
In this phase, the modules designed in the s/w
design phase are implemented using a
programming language.
The purpose of this phase is to implement the
modules in an optimized manner. It should be simple to read and understand.
An optimized code reduces the testing and
maintenance effort.
The output of this phase is to satisfies the
information requirements.
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Testing
Unit testing: It involves testing of differentcomponents of the information system toensure whether or not the components are
functioning correctly Module testing: To ensure whether or not
the modules are functioning properly.
Subsystem Testing System Testing
Acceptance testing
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Implementation
Implementation
Activites
AcquisitionOf H/W
S/W
And
Services
Software
Development
Or modification
End User
Training
System
Documentation
ConversionParallel
Pilot
Phased
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Training
Possible training source
Vendors
System analysts External paid trainer
In-house trainers
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Guidelines for training
Establishing measurable objectives
Using appropriate training methods
Selecting suitable training locations Employing understandable training
materials
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Objectives of a training programme
To enhance communication among the
members of the development team
To provide knowledge about the new
system
To increase user awareness
To obtain support for the new system from
the top management
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Conversion
Direct changeover
Parallel changeover
Modular changeover Phased wise changeover
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Maintenance
The processes of monitoring, evaluating,
and modifying the existing information
systems to make the required or desirable
improvements is known as systemmaintenance.
It is an on going activity. It covers a variety
of activities including removal programs,design errors, updating documentation,
new improved programs implementation
etc.
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Types of Maintenance
Corrective Maintenance
Adaptive MaintenancePerfective Maintenance
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Evaluation
The utilities that are used to evaluate the
system
Possession utility
Form utility
Place utility
Time utility Goal utility