Designing Inputs, Outputs, and Controls

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Designing Inputs, Outputs, and Controls
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Final Exam

• Chapters 1 to 12 and 14 and 15(5th Edition)
• 20 multiple choices
• 3 short questions
• OO diagram
• Use Case
• Class
• Sequence

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Overview

• This chapter focuses on system interfaces, system
  outputs, and system controls that do not require
  much human interaction
• Many system interfaces are electronic
  transmissions or paper outputs to external agents
• System developers need to design and implement
  integrity and security controls to protect system
  and its data
• Outside threats from Internet and e-commerce are
  growing concern

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Identifying System Interfaces

• System interfaces are broadly defined as inputs
  or outputs with minimal or no human intervention
• Inputs from other systems (messages, EDI)
• Highly automated input devices such as scanners
• Inputs that are from data in external databases
• Outputs to external databases
• Outputs to other systems

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Full Range of Inputs and Outputs
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eXtensible Markup Language (XML)

• Extension of HTML that embeds self-defined data
  structures in textual messages
• Transaction that contains data fields can be sent
  with XML codes to define meaning of data fields
• XML provides common system-to-system interface
• XML is simple and readable by people
• Web services is based on XML to send business
  transactions over Internet

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System-to-System Interface Based on XML
Before XML This would be something
like RM010989william jones120 Roundabout
RoadLos Angeles .
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Design of System Inputs

• Identify devices and mechanisms used to enter
  input
• High-level review of most up-to-date methods to
  enter data
• Identify all system inputs and develop list of
  data content for each input
• Provide link between design of application
  software and design of user and system interfaces
• Determine controls and security necessary for
  each system input

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Input Devices and Mechanisms

• Capture data as close to original source as
  possible
• Use electronic devices and automatic entry
  whenever possible
• Avoid human involvement as much as possible
• Seek information in electronic form to avoid data
  re-entry
• Validate and correct information at entry point

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Prevalent Input Devices to Avoid Human Data Entry

• Magnetic card strip readers
• Bar code readers
• Optical character recognition readers and
  scanners
• Radio-frequency identification tags
• Touch screens and devices
• Electronic pens and writing surfaces
• Digitizers, such as digital cameras and digital
  audio devices
• Sensors !!

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Identifying System Interfaces

• Real-time connections (both input and output)
• Sensors !!
• 30 billion RFID tags and 4.6 billion camera
  phones are used around the world today. In
  addition, 200 million smart meters to be operated
  in 2014. Moreover, there were 2 billion people on
  web in 2011
• BIG DATA

Amount of new data stored varies across
geography. New data stored (in Petabytes 1M
Gbytes - (PB)) by geography in 2010. New data
stored is defined as the amount of available
storage used in a given year 9.
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Defining the Details of System Inputs

• Ensure all data inputs are identified and
  specified correctly
• Can use traditional structured models
• Identify automation boundary
• Use DFD fragments
• Segment by program boundaries
• Examine structure charts
• Analyze each module and data couple
• List individual data fields

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Automation Boundary on a System-Level DFD
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List of Inputs for Customer Support System
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Using Object-Oriented Models

• Identifying user and system inputs with OO
  approach has same tasks as traditional approach
• OO diagrams are used instead of DFDs and
  structure charts
• System sequence diagrams identify each incoming
  message
• Design class diagrams and sequence diagrams
  identify and describe input parameters and verify
  characteristics of inputs

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System Sequence Diagram for Create New Order
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Input Messages and Data Parameters from RMO
System Sequence Diagram (Figure 14-10)
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Designing System Outputs

• Determine each type of output
• Make list of specific system outputs required
  based on application design
• Specify any necessary controls to protect
  information provided in output
• Design and prototype output layout
• Ad hoc reports designed as needed by user

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Designing Reports and Statements

• Printed versus electronic
• Types of output reports
• Detailed
• Summary
• Exception
• Executive
• Internal versus external
• Graphical and multimedia presentation

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RMO Summary Report with Drill Down to the
Detailed Report
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Formatting Reports

• What is the objective of report?
• Who is the intended audience?
• What is the media for presentation?
• Avoid information overload
• Format considerations include meaningful
  headings, date of information, date report
  produced, page numbers

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Designing Integrity Controls

• Mechanisms and procedures built into a system to
  safeguard it and information contained within
• Integrity controls
• Built into application and database system to
  safeguard information
• Security controls
• Built into operating system and network

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Objectives of Integrity Controls

• Ensure that only appropriate and correct business
  transactions occur
• Ensure that transactions are recorded and
  processed correctly
• Protect and safeguard assets of the organization
• Software
• Hardware
• Information

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Input Integrity Controls

• Used with all input mechanisms
• Additional level of verification to help reduce
  input errors
• Common control techniques
• Field combination controls
• Value limit controls
• Completeness controls
• Data validation controls

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Database Integrity Controls

• Access controls
• Data encryption
• Transaction controls
• Update controls
• Backup and recovery protection

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Output Integrity Controls

• Ensure output arrives at proper destination and
  is correct, accurate, complete, and current
• Destination controls - output is channeled to
  correct people
• Completeness, accuracy, and correctness controls
• Appropriate information present in output

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Interface Design Guidelines

• Many interface design guidelines have been
  published to help system developers
• Range from general to very specific rules
• System design standards
• General principles and rules that must be
  followed for the interface of any system
  developed by the organization
• Helps to ensure that all user interfaces are
  usable and all systems developed by the
  organization have a similar look and feel

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Visibility and Affordance

• Two key principles to ensure good human-computer
  interaction (Donald Norman)
• Visibility
• A key principle of HCI that states all controls
  should be visible (so users know its
  availability) and provide feedback to indicate
  the control is responding to the users actions
• E.g. a button that can be clicked should be
  visible, and when it is clicked should look like
  it has been pressed to indicate it is responding
• Affordance
• A key principle of HCI that states that the
  appearance of any control should suggest its
  functionality
• e.g. a button affords clicking, a scroll bar
  affords scrolling, an item in a list affords
  selecting etc.
• Applies to objects on the desktop

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Implications for designers

• If designers make all controls visible and clear
  more likely the interface will be usable
• Most users are now familiar with Windows user
  interface and common Windows controls
• Not necessarily with Iphone/Android Interfaces
• These principles should also be applied carefully
  to design of web pages, where there are new types
  of controls and possible designs of interfaces
  (not standardized)

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Eight Golden Rules

• Ben Shneiderman proposes eight underlying
  principles applicable to most interactive systems
  (and key to usability)
• Strive for consistency
• Enable frequent users to use short cuts
• Offer informative feedback
• Design dialogs to yield closure
• Offer simple error handling
• Permit easy reversal of actions
• Support internal locus of control
• Reduce short-term memory load

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1. Strive for Consistency

• Information arranged on forms, the names and
  arrangement of menus, the size and shape of icons
  etc. should be consistent throughout the system
• This allows for many actions to become automatic
• If a new application comes along with a different
  way of functioning have to relearn all the basic
  operations
• Apple Macintosh was the first to emphasize the
  benefits of consistency
• Mac applications were consistent and a standards
  document was created for people writing Mac
  applications (so if you knew one you could figure
  out other applications easily since they were
  consistent)
• E.g. consistency in the menu bar for File, Edit
  and Format
• However some applications may not fit such
  guidelines and inconsistency may be useful for
  differentiating applications (for running and
  learning)

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2. Enable Frequent Users to Use Short Cuts

• Users who work with one application all the time
  are willing to invest time to learn short cuts
• They begin to lose patience with long menu
  sequences when they know exactly what they want
  to do
• Short-cut keys can reduce the number of
  interactions for a given task
• Designers can provide macro facilities for users
  to create their own short cuts
• E.g. mail order entry clerks at RMO wouldnt want
  long multiple menus to slow them down, but
  instead short-cuts would make them more productive

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3. Offer Informative Feedback

• Every action a user takes should result in some
  type of feedback from the computer
• Eg. If the user clicks a button it should
  visually change and perhaps make a sound to
  indicate it has responded
• Feedback of information to the user is also
  important
• E.g. if a mail-order clerk enters a customer ID
  number in the screen, the computer should display
  the name and address for confirmation by the
  clerk
• E.g. if the clerk enters a product ID for the
  order, the system should display a description of
  the product

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4. Design Dialogs to Yield Closure

• Each dialog with the system should be organized
  with a clear sequence (with a beginning and an
  end)
• Reading ones email
• If the system requirements are defined as events
  to which the system responds, each event leads to
  processing of one specific, well-defined activity
• Traditional approach
• Each activity is defined by data flow diagrams
  and structured English
• Object-oriented approach
• Each activity (a use case) might be further
  defined as multiple scenarios, each with a flow
  of events

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5. Offer Simple Error Handling

• Errors can be costly so designers must try to
  prevent users from making errors
• Better way is by limiting available options and
  allowing user to choose from valid options at any
  point in the dialog
• Adequate feedback also reduces errors
• When errors occur need ways to handle it
• Error messages should state specifically what is
  wrong and explain how to create it
• Avoid message that scare or blame the user
• e.g. FATAL ERROR 2001
• Also provide information that makes it easy to
  correct the error
• e.g. The date of birth entered is not valid.
  Check to be sure only numeric characters in
  appropriate ranges are entered in the date of
  birth fields

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6. Permit Easy Reversal of Actions

• Users need to feel that they can explore options
  and take actions that can be canceled or reversed
  easily
• Allows users to learn about the system by
  exploring
• If they make a mistake, they can cancel the
  action
• Should include cancel buttons on all dialog boxes
• Also if user is going to delete something
  substantial (e.g. a file) the system should ask
  the user to confirm the action

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7. Support Internal Locus of Control

• Experienced users want to feel they are in charge
  of the system and the system responds to them
• They should not be forced to do anything or made
  to feel the system is controlling them
• Much of this comfort and control is provided by
  the wording of prompts and messages
• Writing out a dialog can help to lead to such a
  design

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8. Reduce Short-Term Memory Load

• People have short-term memory limitations
• People remember only about seven chunks of
  information at a time
• Interface designer cannot assume the user will
  remember anything from form to form, or dialog
  box to dialog box
• If user has to stop and ask Now what was the
  filename? The customer ID? then the design is
  placing a burden on the users memory

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Integrity Controls to Prevent Fraud

• Three conditions are present in fraud cases
• Personal pressure, such as desire to maintain
  extravagant lifestyle
• Rationalizations, including I will repay this
  money or I have this coming
• Opportunity, such as unverified cash receipts
• Control of fraud requires both manual procedures
  and computer integrity controls

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Fraud Risks and Prevention Techniques
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Designing Security Controls

• Security controls protect assets of organization
  from all threats
• External threats such as hackers, viruses, worms,
  and message overload attacks
• Security control objectives
• Maintain stable, functioning operating
  environment for users and application systems (24
  x 7)
• Protect information and transactions during
  transmission outside organization (public
  carriers)

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Security for Access to Systems

• Used to control access to any resource managed by
  operating system or network
• User categories
• Unauthorized user no authorization to access
• Registered user authorized to access system
• Privileged user authorized to administrate
  system
• Organized so that all resources can be accessed
  with same unique ID/password combination

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Users and Access Roles to Computer Systems
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Managing User Access

• Most common technique is user ID / password
• Authorization Is the user permitted to access?
• Access control list users with rights to access
• Authentication Is the user who they claim to
  be?
• Smart card computer-readable plastic card with
  embedded security information
• Biometric devices keystroke patterns,
  fingerprinting, retinal scans, voice
  characteristics

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Data Security

• Data and files themselves must be secure
• Encryption primary security method
• Altering data so unauthorized users cannot view
• Decryption
• Altering encrypted data back to its original
  state
• Symmetric key same key encrypts and decrypts
• Asymmetric key different key decrypts
• Public key public encrypts private decrypts

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Symmetric Key Encryption
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Asymmetric Key Encryption
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Digital Signatures and Certificates

• Encryption of messages enables secure exchange of
  information between two entities with appropriate
  keys
• Digital signature encrypts document with private
  key to verify document author
• Digital certificate is institutions name and
  public key that is encrypted and certified by
  third party
• Certifying authority
• VeriSign or Equifax

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Using a Digital Certificate
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Final Exam

• Chapters 1 to 12 and 14 and 15(5th Edition)
• 20 multiple choices
• 3 short questions
• OO diagram
• Use Case
• Class
• Sequence