Transcript Chapter_9

CHAPTER
Section A Information Systems
PARSONS/OJA
9
Information
Systems
Analysis and
Design
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Chapter
9
Information Systems Analysis and Design
Chapter PREVIEW
 Information systems
 Types of information systems
 System development life cycle (SDLC)
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What is an information system?
 An information system collects, stores, and
processes data to provide useful, accurate,
and timely information
 Information is used to make decisions
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Who uses information systems?
 Top management makes decisions with long-range impact.
Referred to as strategic planning
 Summarized information for entire company
 Mid-level managers set incremental goals that can be
achieved in a year or less—a process referred to as
tactical planning
 Information relevant to manager’s responsibilities
 Low-level managers are responsible for scheduling
employees, ordering supplies, and other activities that
make day-to-day operations run smoothly—a process
referred to as operational planning
 Detailed information
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How do information systems help the
people in an organization?
 An information system can help the people in an
organization perform their jobs more quickly and
effectively by automating routine tasks
 Online banking
 One of the major functions of an information
system is to help people make decisions in
response to problems
 Price for flight from Dallas to Chicago on
Southwest
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Do organizations require different kinds
of information systems?
 Because organizations have different missions,
face different threats, and encounter different
opportunities, they require different kinds of
information systems
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Types of information systems
 Office automation systems
 Transaction processing systems
 Management information system
 Decision support system
 Expert systems
 Neural networks
 Data base mining
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Office Automation Systems:
 An office automation system “automates,” or
computerizes, routine office tasks
 Reorder of inventory
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Transaction Processing Systems:
What’s a transaction?
 A transaction is an event that requires a manual
or computer-based activity
 Order a cheeseburger at McDonalds
 Most modern transaction processing systems use
online processing. Such systems are often
referred to as OLTPS (online transaction
processing systems)
 Adding/dropping classes at EIU
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What are common examples of
transaction processing systems?
 A point-of-sale (POS) system records items
purchased at each cash register, and calculates
the total amount due for each sale
 An order-entry/invoice system provides a way
to input, view, modify, and delete customer orders
 A general accounting system records the
financial status of a business by keeping track of
income, expenses, and assets
 An e-commerce system collects orders and
processes credit card payments
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Management Information Systems: What is a
management information system?
 A management information system (MIS)
refers to a type of information system that uses
the data collected by a transaction processing
system, but manipulates that data to create
reports that managers can use to make routine
business decisions in response to structured
problems
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What is a management information
system?
 One of the major goals of an MIS is to increase the efficiency
of managerial activity
 A summary report combines or groups data and often shows
totals
 Top management
 An exception report contains information that is outside of
normal or acceptable ranges
 Middle management: regions where GM SUV sales
below monthly forecast
 Scheduled reports follow a fixed format and are produced
according to a preset timetable
 An ad hoc report is a customized report, generated to supply
specific information not available in scheduled reports
 Impact of SARS on airlines at Toronto’s airport
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How does an MIS differ from a TPS?
 Whereas a TPS simply records data, an MIS can
consolidate data by grouping and summarizing it
 TPS provides raw material
 MIS is finished product
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What are the limitations of a
management information system?
 A traditional MIS is based on the data collected
by a transaction processing system
 Employee morale
 The reports generated by an MIS are limited by
the processing capabilities of the database
software.
 The MIS cannot typically be used to create
models or projections
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Decision Support Systems: What’s a
decision support system?
 A decision support system (DSS) helps
people make decisions by directly manipulating
data, analyzing data from external sources,
generating statistical projections, and creating
data models of various scenarios
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What’s a decision support system?
 A DSS does not make decisions, however. That task
remains the responsibility of the human decision maker
 A decision model is a numerical representation of a
realistic situation
 A decision query is a question or set of instructions
describing data that must be gathered to make a decision
 Pujols has hit .537 against left handed pitchers
 A DSS typically includes modeling tools so managers can
create a numerical representation of a situation and explore
“what-if” alternatives
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What are the limitations of a DSS?
 A DSS helps people manipulate the data
necessary to make a decision, but does not
actually make a decision
 A DSS is appropriate in situations where it is
used by trained professionals
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Expert Systems: What is an expert
system?
 An expert system, sometimes referred to as a
“knowledge-based system,” is a computer system
designed to analyze data and produce a
recommendation, diagnosis, or decision
based on a set of facts and rules
 The facts and rules for an expert system are
typically derived by interviewing one or more
experts, and then incorporated into a knowledge
base
 What percent of my portfolio should be
invested in stocks?
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Expert Systems: What is an expert
system?
 Use data base of knowledge to draw conclusions
 Data base is If, Then knowledge
• Rules of thumb provided by expert individuals
 Can handle routine situations with great accuracy;
leaves complex situations to humans
 Can explain why it reached conclusion: loan denied
because…
 Each expert system is designed to make decisions in a
particular area or “domain”
 Credit card fraud, HP printer support
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Neural networks
 An expert system begins with a set of facts and rules. But if
the rules are not known, a computer can “learn” how to
make decisions based on hundreds or thousands of
lightning-fast trial and error attempts
 A neural network uses computer circuitry to simulate
the way a brain might process information, learn, and
remember
 Looks for patterns that work
 May use genetic algorithms where only the best
solutions “survive”
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Neural networks are used when…
 There are not “hard and fast” solutions such as
pattern recognition and forecasting
 Neural nets are well suited to problems that
people are good at solving, but for which
computers are not.
• What are the characteristics of a terrorist?
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Data base mining
 automated extraction of predictive information
from large databases
 What customer will respond to a catalog of
bird feed and houses?
 Deep Blue used data mining to calculate all
possible moves and selected best move
 Confirming or discovering patterns in huge data
bases
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Data base mining
• Pattern validation:
 Confirm existence of expected patterns.
• Visits to Health Service in November
versus September
 Top down data mining
 May not ask about the right patterns.
• Pattern discovery
 75% of the purchasers of low-fat ice
cream buy bottled water
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What is a system development life
cycle?
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Planning Phase: How does an
information system project begin?
 An information system project begins with a
planning phase
 The goal of these activities is to create a Project
Development Plan
 This planning document includes:
 A short description of the project, including its
scope
 A justification for the project
 A list of project team participants
 A schedule for the project, including an outline
of its phases
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Justify Project: Why are new
information systems developed?
 The justification for a new information system
usually emerges from a serious problem with the
current system, or from an opportunity to improve
an organization’s products or services using
technology
 Perhaps your network can’t handle traffic
trying to use the Internet at peak times
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Analysis Phase: What happens in the
analysis phase?
 The goal of the analysis
phase is to produce a list
of requirements for a new
or revised information
system
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Is it really important to understand the current
system before planning a new system?
 Typically, a new information system is designed
to replace a system or process that is already in
place
 It is important to study the current system to
understand its strengths and weaknesses before
planning a new system
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Determine System Requirements: How does the
project team determine what the new system
should do?
 System requirements are the criteria for
successfully solving the problem or problems
identified in an information system
 They also serve as an evaluation checklist at the
end of the development project, so they are
sometimes called success factors
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What marks the end of the analysis
phase of the SDLC?
 The analysis phase concludes when the project
team produces a written report that documents its
findings
 The System Requirements Report typically
contains diagrams that illustrate what the new
information system should do
 Should we do the same thing when we buy
a personal computer?
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Design Phase: What happens in the
design phase?
 In the design phase of the SDLC, the project
team must figure out HOW the new system will
fulfill the requirements specified in the System
Requirements Report
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Identify Potential Solutions: How does the
project team come up with solutions?
 There might be more than one way to solve the
problems and meet the requirements identified in
the analysis phase of the SDLC
 The project team should identify several potential
hardware and software solutions by
“brainstorming” and researching case studies on
Web sites and in computer magazines
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What kinds of hardware alternatives are
available?
 A myriad of hardware options are available for
information systems
 Mainframes, servers, and personal computers
are the most commonly used components, but in
some information systems, handhelds, or even
supercomputers, play a role
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What kinds of software alternatives are
available?
 The project team might consider software
alternatives, such as whether to construct the
system “from scratch,” use an application
development tool, or commercial software
 Creating an information system “from scratch”
using a programming language can take many
months or years
 An application development tool is essentially
a type of software construction kit containing
building blocks that can be assembled into a
software product
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What kinds of software alternatives are
available?
 Commercial software for an information system
is usually a series of pre-programmed software
modules, supplied by a software developer,
consulting company, or value-added reseller
(VAR)
 A turnkey system is essentially an “information
system in a box” which consists of hardware and
commercial software designed to offer a
complete information system solution
 A turnkey system must be extensively evaluated
to determine whether it can satisfy system
requirements
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Evaluate Solutions and Select the Best: How
does the team choose the best solution?
 To determine the best solution the project team
devises a list of criteria for comparing each of the
potential solutions
 Each criterion is assigned a weight to indicate its
importance. The project team then evaluates the
criteria for each solution and assigns raw scores
 Sound complicated? It isn’t, especially if the
project team uses a decision table
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Select Hardware and Software: How does the
project team find the right hardware and
software for the new information system?
 Once the project team selects a solution, the
next task is to select the hardware and
software needed to implement the solution
 The method for selecting the hardware, software,
and vendor depends on the project team’s
understanding of what is required for the solution
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Develop Application Specifications: What
happens after the project team selects a solution?
 Exactly what happens next in the system design
phase depends on the type of solution selected
 If the project team selected a solution that
requires custom programming, the team’s
systems analysts will create a set of application
specifications
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What happens to the completed
specifications?
 Application specifications are similar to the pages
of an architectural blueprint that show the
detailed plan for electrical wiring or plumbing
 In a large information systems project, the
specifications are given to a programming team
or application developer who creates the
software
 In a small information systems project, you as the
user might develop your own specifications
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Section D Implementation and
Maintenance
Implementation Phase: What happens
during the implementation phase?
 During the
implementation phase of
the SDLC, the project
team supervises the tasks
necessary to construct the
new information system
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Purchase and Install Hardware and Software:
Do most new information systems require new
hardware?
 Most new information systems require new
hardware, which can either replace old
equipment, or be connected to existing
equipment
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How about new software?
 Many information systems require new software,
such as a commercial application, a
programming language, an application
development tool, or an expert system shell
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Test Applications: How can the team ensure that
a new information system works?
 A rigorous testing process is the only way to
make sure that a new information system works
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What is application testing?
 Application testing is the process of trying out
various sequences of input values and checking the
results to verify that the application works correctly
 As each application module is completed, it
undergoes unit testing to ensure that it operates
reliably and correctly
 When all modules have been completed and
tested, integration testing is performed to ensure
that the modules operate together correctly
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Train Users: How do employees learn
how to use the new information system?
 In preparation for using a new information
system, users need extensive training, which
might include hardware operation, data entry, and
backup procedures
 Training sessions can be conducted by members
of the team or professional trainers
 Resistance to change!!!
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Convert to New System: How does a business
switch from the old system to the new system?
 System conversion refers to the process of
deactivating an old information system and
activating the new one
 A direct (crash) conversion means that the old
system is completely deactivated and the new
system is immediately activated
 A parallel conversion avoids some of the risk
because the old system remains in service while
some or all of the new system is activated
 In a phased conversion, the new system is
activated one module at a time
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How does a business switch from the
old system to the new system?
 A pilot conversion works well in organizations
with several branches that have independent
information processing systems
 The new information system is activated at
one branch
 If the system works correctly at one branch, it
is activated at the next branch
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Maintenance Phase: What happens
during the maintenance phase?
 The maintenance
phase of the SDLC
involves day-to-day
operation of the system,
making modifications to
improve performance,
and correcting problems
 The maintenance phase
of the SDLC is the most
expensive because it
lasts until the system is
retired
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Why do maintenance activities include
user support?
 Even after-in-depth training, employees
sometimes forget procedures, or have difficulty
when they encounter a new set of circumstances
 Many organizations establish a help desk to
handle end-user problems
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Does an information system change
during the maintenance phase?
 The term “maintenance phase” is a bit misleading
 Changes during the maintenance phase typically
include the following:
 Upgrades to operating system and commercial
software
 User interface revisions
 Application software revisions
 Hardware replacements
 Security upgrades
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When does the maintenance phase
end?
 The maintenance phase continues until an
information system is no longer cost effective, or
until changes in the organization make the
information system obsolete
 Then cycle begins again with the
development of a replacement system
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