Chapter 17 Successfully Implementing The Information System Systems Analysis and Design

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Chapter 17
Successfully Implementing
The Information System
Systems Analysis and Design
Kendall & Kendall
Sixth Edition
Major Topics
• Client/server computing
• Network types
• Groupware
• Training
• Security
• Organizational metaphors
• Evaluation
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Implementation
• Implementation is the process of
assuring that the information system is
operational.
• Well-trained users are involved in its
operation.
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Distributed Systems
• Distributed systems use
telecommunications technology and
database management to interconnect
people.
• A distributed system includes work stations
that can communicate with each other and
with data processors.
• The distributed system may have different
configurations of data processors.
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Client/Server Computing
• The client/server (C/S) model consists
of clients request and the server
fulfillment of the request.
• The client is a networked computer,
running a GUI interface.
• A file server stores programs and data
• A print server receives and stores files
to be printed.
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Advantages and Disadvantages
of Client/Server
•
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The advantages of a client/server system are
greater computer power and greater
opportunity to customize applications.
The disadvantages of a client/server system
are greater expense and applications must be
written as two separate software components
running on separate machines.
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Network Types
Standard types of networks include the
wide-area network (WAN), the local
area network (LAN), and the wireless
local area network (WLAN).
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Wireless Local Area Network
(WLAN)
• Called Wi-Fi, wireless fidelity
• Can include encryption wired equivalent
privacy (WEP) for security
• Cheap to set up
• Flexible
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Wireless Local Area Network
(WLAN) (Continued)
•
Concerns:
• Security.
• Signal integrity.
• Wi-Fi networks are prone to interference from
•
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systems operating nearby in the same frequency
spectrum.
Bluetooth is suitable for personal networks and
can include computers, printers, handheld devices,
phones, keyboards, mice and household
appliances.
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Network Configurations
There are four types of network
configurations:
• Hierarchical.
• Star.
• Ring.
• Bus.
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Hierarchical
• A hierarchical network will contain
several levels, with a host at the top.
• A host computer has many smaller
computers that only communicate with
the host, not with each other.
• The host controls all other nodes.
• Computers on the same level do not
communicate with each other.
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Star
The host computer can communicate
with other computers that can
communicate with each other only
through the host.
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Ring
• All computers communicate with each
other, passing messages around the
ring.
• There is no central computer.
• Each node is in direct communication
with its neighbor.
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Bus
• A single central cable is used to connect
all the computers.
• It has a single, central cable that serves
as the only communication path
connecting several different devices.
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Network Models
Several models are available for
designing a network:
• A network decomposition diagram provides
an overview of the system and is drawn
first.
• A hub connectivity shows how the major
hubs are connected and is drawn second
• A workstation connectivity diagram shows
the details of connecting the workstations.
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Network Decomposition and Hub
Connectivity Diagram Symbols
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Network Decomposition Diagram
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Hub Connectivity Diagram
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Workstation Connectivity Diagram
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Groupware
Groupware is software that supports
people working together in an
organization.
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Groupware Functions
Groupware helps group members to:
• Schedule and attend meetings.
• Share data.
• Create and analyze documents.
• Communicate in unstructured communication via
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email.
Hold group conferences.
Perform departmental-level image management.
Manage and monitor workflow.
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Advantages of Distributed
Systems
Advantages of distributed systems are:
• Data are stored where it does not affect
the processing of online real-time
transaction processing.
• Data are stored using less expensive media
at local sites.
• Lowered equipment costs.
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Advantages of Distributed
Systems
Advantages of distributed systems are
(continued):
• Provide flexibility in choice of equipment
manufacturer.
• Initially less expensive than large systems.
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Disadvantages of Distributed
Systems
Disadvantages of distributed systems are:
• Difficulty in achieving reliable system.
• Security may be breached.
• The relationships between subsystems
must not be ignored.
• Choosing the wrong level of computing to
support.
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Training
•
•
New system training must be performed.
Analysts must consider:
• Who needs to be trained.
• Who will train them.
• Objectives of training.
• Methods of instruction to be used.
• Sites.
• Materials.
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Sources of Training
Possible sources of training for users of
information systems include:
• Vendors.
• Systems analysts.
• External paid trainers.
• In-house trainers.
• Other system users.
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Concerns for Training Objectives,
Method, Sites and Materials
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Conversion Strategies
Five conversion strategies are:
• Direct changeover.
• Parallel conversion.
• Gradual or Phased conversion.
• Modular prototype conversion.
• Distributed conversion.
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Conversion Strategies
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Security
• Security considerations must be
included when implementing a system.
• These include:
• Physical security.
• Logical security.
• Behavioral security.
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Security (Continued)
• Physical security is controlling access to
physical computer resources.
• Logical security is controlling software
access.
• Behavioral security is building
procedures to prevent persons from
misusing computer hardware and
software.
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Web Security
Precautions used to protect the
computer network from both internal
and external Web security threats
include:
• Virus protection software.
• Email filtering products.
• URL filtering products.
• Firewalls, gateways, and virtual private
networks.
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Web Security
•
Precautions used to protect the computer
network from both internal and external Web
security threats include (continued):
• Intrusion detection products.
• Vulnerability management products.
• Security technologies such as secure socket
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layering (SSL) for authentication.
Encryption technologies.
Public key infrastructure (PKI) use and obtaining a
digital certificate.
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Ecommerce Privacy Guidelines
• Privacy is essential to ecommerce.
• Some privacy policy guidelines are:
• Start with a corporate policy on privacy.
• Only ask for information required to
complete the transaction.
• Make it optional for customers to fill out
personal information on the Web site.
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Ecommerce Privacy Guidelines
• Some privacy policy guidelines are
(continued):
• Use sources that allow you to obtain
anonymous information about classes of
customers.
• Be ethical in data gathering.
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Other Conversion Considerations
•
•
•
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Ordering equipment
Ordering external supplies, such as toner
cartridges, paper, preprinted forms and so on
Appointing a manager to supervise the
preparation of the installation site
Planning, scheduling, and supervising IT
personnel who convert files and databases
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Evaluation Approaches
Several evaluation approaches can be
used:
• Cost-benefit analysis.
• Revised decision evaluation approach.
• User involvement evaluations.
• The information system utility approach.
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Organizational Metaphors
Organizational metaphors may be used
to assist in a successful implementation
of a new system.
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Organizational Metaphors
(Continued)
•
•
•
•
•
Zoo
Jungle
War
Journey
Machine
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Society
Family
Organism
Game
17-39
Organizational Metaphors and
Types of Information Systems
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Interpreting Organizational
Metaphors
• Zoo indicates success is likely with
traditional MIS systems and decision
support systems.
• Jungle indicates success is likely with
decision support systems, cooperative
systems, competitive systems, and
executive information systems.
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Interpreting Organizational
Metaphors (Continued)
• War indicates success is likely with
competitive systems.
• Journey indicates success is likely with
cooperative systems.
• Machine indicates success is likely with
traditional MIS systems and expert
systems/artificial intelligence.
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Interpreting Organizational
Metaphors (Continued)
• Society indicates success is likely with
traditional MIS systems and decision
support systems.
• Family indicates success is likely with
traditional MIS systems and decision
support systems.
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Interpreting Organizational
Metaphors (Continued)
• Organism indicates success is likely with
decision support systems, expert
systems/artificial intelligence,
cooperative systems, competitive
systems, and executive information
systems.
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Interpreting Organizational
Metaphors (Continued)
• Game indicates success is likely with
expert systems/artificial intelligence,
cooperative systems, competitive
systems, and executive information
systems.
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Information System Utility
Evaluation
•
The information system utility framework is a
way to evaluate a new system based on
utilities of:
• Possession.
• Form.
• Place.
• Time.
• Actualization.
• Goal.
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Information System Utility
Evaluation (Continued)
• Possession utility answers the question
of who should receive output.
• Goal utility answers the why of
information systems by asking whether
the output has value in helping the
organization achieve its objectives.
• Place utility answers the question of
where information is distributed.
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Information System Utility
Evaluation (Continued)
• Form utility answers the question of
what kind of output is distributed to the
decision maker.
• Time utility answers the question of
when information is delivered.
• Actualization utility involves how the
information is introduced and used by
the decision maker.
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Web Site Evaluation
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•
Corporate Web sites should be evaluated.
The following is a list of key things to learn
about the Web site visitors:
• Know how often the Web site is visited.
• Learn details about specific pages on the site.
• Find out demographic and other information about
Web site visitors.
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Web Site Evaluation
•
The following is a list of key things to learn
about the Web site visitors (continued):
• Discover if visitors can properly fill out the Web
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forms.
Find out who is referring Web site visitors to the
client’s Web site.
Determine what browsers visitors are using.
Find out if the client’s Web site visitors are
interested in advertising the Web site.
© 2005 Pearson Prentice Hall
17-50
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