ch5 - input design and prototyping

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Copyright © 2000 The McGraw-Hill Companies. All Rights reserved

Whitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS 5th Edition

5C H A P T E R

INPUT DESIGN AND PROTOTYPING

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Chapter Fourteen Input Design & Prototyping

• Define the appropriate format and media for a computer input.

• Explain the difference between data capture, data entry, and data processing.

• Identify and describe several automatic data collection technologies.

• Apply human factors to the design of computer inputs.• Design internal controls for computer inputs.• Select proper screen-based controls for input attributes

that are to appear on a GUI input screen.• Design a web-based input interface.

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Chapter Map

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Taxonomy for Computer InputsProcess

Method

Data Capture Data Entry Data Processing

Keyboard

Mouse

Touch Screen

collected into batch files keyboard. This is the most (disk) for processing as a

but also the most prone to

Data can be collected real

keyboard to simplify data commonly associated with

graphical user interfaces to reduce errors through

screen display or handheld choices are processed

touch commands and data

Data usually captured on a business form that becomes the source document for input.

-time (over the phone).

Data entered via

common input method,

errors.

OLD: Data can be

batch.

NEW: Data processed as soon as it has been keyed.

Same as above. Used in conjunction with

entry.

Mouse serves as a pointing device for a screen. Can be with

point-and-click choices.

Same as above, but the use of a mouse is most

on-line and real-timeprocessing.

Same as above. Data entered on a touch

device.

Data entry users either

choices, or enter data using handwriting recognition.

On PCs, touch screen

same as above.

On handheld computers, data is stored on the handheld for later processing as a remote batch.

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Taxonomy for Computer Inputs (continued)Process

Method


transaction) as humanly processed immediately as

customer (e.g., retail cash

combination of the other

to the source as possible, even when the customer is

processed immediately as

remotely located (e.g., at

marks or precisely formed

structure and limited input

processed immediately as spoken. This technology is not as mature and much less reliable and common

education for test scoring, course evaluations, and

Point of Sale Data is captured as close to the point of sale (or

possible. No source documents.

Data is often entered directly by the customer (e.g., ATM) or by an employee directly interacting with the

register).

Input requires specialized, dedicated terminals that utilize some

techniques in this table.

Data is almost always

a transaction or inquiry.

Sound Data is captured as close

home or their place of employment).

Data is entered using touch-tones (typically from a telephone).

Usually requires fairly rigid command menu

options.



Speech Same as sound. Data (and commands) are

than other techniques.



Optical Mark Data is recorded on optical scan sheets as

letters, numbers, and punctuation.

This is the oldest form of automatic data capture.

Eliminates the need for data entry,

(Very commonly used in

surveys.)

Data is almost always processed as a batch.

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Taxonomy for Computer Inputs (concluded)Process

Method


recorded on forms that are subsequently completed

common of which is bank

number, account number,

on a device to be carried

Magnetic Ink Data is usually pre-

by the customer.

The customer records additional data on the form.

A magnetic ink reader reads the magnetized data.

The customer-added data -must be entered using another input method.

This technique is used in applications requiring high accuracy and security, the most

checks (for check

bank id).

Data is almost always processed as a batch.

Electromagnetic Data is recorded directly on the object to be described by data.

Data is transmitted by radio frequency.

Data is almost always processed immediately.

Smartcard Data is recorded directly

by the customer, employee, or other individual that is described by that data.

Data is read by smartcard readers.

Data is almost always processed immediately.

Biometric Unique human character-istics become data.

Data is read by biometric sensors.

Primary applications are security and medical monitoring.

Data is processed immediately.

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Data Capture, Entry, and Processing

Data capture is the identification and acquisition of new data (at its source).

– Source documents are forms used to record business transactions in terms of data that describe those transactions.

Data entry is the process of translating the source data or document (above) into a computer readable format.

Data processing is all processing that occurs on the data after it is input from a machine readable form.

– In batch processing, the entered data is collected into files called batches and processed as a complete batch.

– In on-line processing, the captured data is processed immediately

– In remote batch processing, data is entered and edited on-line, but collected into batches for subsequent processing.

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Input Implementation Methods

• Keyboard• Mouse• Point-of-sale terminals• Sound and speech• Automatic data capture

– Optical mark recognition (OMR)• Bar codes

– Optical character recognition (OCR)– Magnetic Ink– Electromagnetic transmission– Smart cards– Biometric

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Automatic Identification: Bar Codes

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Input Design Guidelines

• Capture only variable data.• Do not capture data that can calculated or stored in

computer programs as constants.• Use business codes for appropriate attributes.




Source Document / Form Design Guidelines

• Include instructions for completing the form.• Minimize the amount of handwriting.• Data to be entered (keyed) should be sequenced so that

it can be read like a book, that is, top-to-bottom and left-to-right.

• When possible, based input design on known descriptions / metaphore / images.




Bad Flow in a Form




Good Flow in a Form




Metaphoric Screen Design




Internal Controls for Inputs

• Each input, and the total number of inputs should be monitored (to minimize the risk of lost transactions).– For batch processing

• Use batch control slips• Use one-for-one checks against post-processing detail reports

– For on-line systems• Log each transaction as it occurs• Assign each transaction a confirmation number (common in

web-based systems)

• Validate all data– Existence checks– Data type checks– Domain checks– Combination checks– Self-checking digits– Format checks




Repository-Based Prototyping and Development




GUI Components (or Controls)

• Common GUI controls (for both Windows and Web interfaces)– Text boxes– Radio buttons– Check boxes– List boxes– Drop down lists– Combination boxes– Spin boxes– Buttons– Hyperlinks (yes, also for Windows applications—see Quicken

2000)

• Advanced controls (mostly for Windows interfaces)– Drop down calendars– Slider edit controls– Masked edit controls– Ellipsis controls– Alternate numerical spinners– Check list boxes– Check tree boxes




Common GUI Components




Advanced GUI Components




Advanced GUI Components (continued)




Input Design Process

1. Identify system inputs and review logical requirements.

2. Select appropriate input components/controls.

3. As necessary, design any source documents.

4. Design, validate and test inputs using some combination of:1.Layout tools (e.g., hand sketches, spacing charts, or

CASE tools.

2.Prototyping tools (e.g., spreadsheet, PC DBMS, 4GL)




A Logical Data Structure for Input Requirements

ORDER = ORDER NUMBER+ ORDER DATE+ CUSTOMER NUMBER+ CUSTOMER NAME+ CUSTOMER SHIPPING ADDRESS = ADDRESS >+ ( CUSTOMER BILLING ADDRESS = ADDRESS

> )+ 1 { PRODUCT NUMBER +

QUANTITY ORDERED } n+ ( DEFAULT CREDIT CARD NUMBER )

ADDRESS = ( POST OFFICE BOX NUMBER )+ STREET ADDRESS+ CITY+ STATE+ POSTAL ZONE




Input Prototype for Data Maintenance




Input Prototype for Transaction




Input Prototype for Data Maintenance




Input Prototype for Web Interface

ch5 - input design and prototyping

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