Systems analysis and design methods 7th whitten and benley chapter 12

Input Design and Prototyping Introduction  The chapter will address the following questions:        What is the appropriate format and media for a computer input? What is the difference between data capture, data entry, and data input? Can you identify and describe several automatic data collection technologies? How you apply human factors to the design of computer inputs? How you design internal controls for computer inputs? How you design a good source document for capturing transaction data? How you select proper screen-based controls for input attributes that are to appear on a GUI input screen? Input Design and Prototyping Methods & Issues for Data Capture & Input  Data Capture, Data Entry, and Data Input     To input business data into a computer, the analyst may have to design source documents, input screens, and methods and procedures for getting the data into the computer Data accompanies business events called transactions Systems analysts must determine when and how to capture the data  Data capture is the identification of new data to be input  It's always best to capture the data as soon as possible after it is originated Traditionally, special paper forms called source documents were used to capture the data  A source document is a paper form used to record data that will eventually be input to a computer Input Design and Prototyping Methods & Issues for Data Capture & Input  Data Capture, Data Entry, and Data Input   Traditionally, special paper forms called source documents were used to capture the data  A source document is a paper form used to record data that will eventually be input to a computer With advances in video display technology, screen display forms are able to duplicate the appearance of almost any paper based form  Screen display forms and source documents must be designed to be easy for the system user to complete and should facilitate rapid data entry • Data entry is the process of translating the source document into a machine-readable format That format may be a magnetic disk, an optical-mark form, a magnetic tape, or a floppy diskette, to name a few Input Design and Prototyping Methods & Issues for Data Capture & Input  Data Capture, Data Entry, and Data Input  Data input is performed after data entry  Data input is the actual entry of data in a machine-readable format into the computer Input Design and Prototyping Methods & Issues for Data Capture & Input  Modern Input Methods: Batch versus On-Line Inputs  Input methods can be broadly classified as either batch or on-line  Batch input is the oldest and most traditional input method Source documents or forms are collected and then periodically forwarded to data entry operators, who key the data using a data entry device that translates the data into a machinereadable format  The most common medium for batch input data are Key-todisk (KTD) and key-to-tape (KTT) workstations that transcribe data to magnetic disks and magnetic tape, respectively • The data can be corrected, because it is initially placed into a buffer Input Design and Prototyping Methods & Issues for Data Capture & Input  Modern Input Methods: Batch versus On-Line Inputs  Today, most, but not all, systems have been converted or are being converted to on-line methods  On-line input is the capture of data at its point of origin in the business and the direct inputting of that data to the computer, preferably as soon as possible after the data originates  The on-line system includes a monitor screen and keyboard that are directly connected to a computer system  Most new applications being developed today consists of screens having a “graphical” looking appearance called a graphical user interface (GUI) Input Design and Prototyping Methods & Issues for Data Capture & Input  Modern Input Methods: Batch versus On-Line Inputs  Today, most, but not all, systems have been converted or are being converted to on-line methods  Remote batch offers on-line advantages for data that is best processed in batches The data is input on-line with on-line editing Microcomputers or minicomputer systems can be used to handle this on-line input and editing The data is not immediately processed Instead, it is batched, usually to some type of magnetic media At an appropriate time, the data is uploaded to the main computer, merged, and subsequently processed as a batch Remote batch is also called deferred batch or deferred processing Input Design and Prototyping Methods & Issues for Data Capture & Input  Trends in Automatic Data Collection Technology   Using today's technology, most if not all human intervention associated with the input methods previously discussed can be eliminated  By eliminating human intervention, the time-delay and errors associated with human interaction can be decreased Biometric:  Biometric ADC systems consist of sensors that capture an individuals characteristic or trait, digitizes the image pattern, and then compares the image to stored patterns for identification  Biometric ADC are popular because they offer the most accurate and reliable means for identification Input Design and Prototyping Methods & Issues for Data Capture & Input  Trends in Automatic Data Collection Technology  Electromagnetic:  Electromagnetic ADC technology is based on the use of radio frequency to identify physical objects • This technology involves attaching a tag and antenna to the physical object that is to be tracked • The tag contains memory that used to identify the object that is being tracked • The tag can be read by a reader whenever the object resides within the electromagnetic field generated by the reader Input Design and Prototyping Methods & Issues for Data Capture & Input  Trends in Automatic Data Collection Technology  Magnetic:  Magnetic ADC technology involves using magnetic stripe cards, but also may include the use of magnetic ink character recognition (MICR)  MICR is most widely used in the banking industry 10 Input Design and Prototyping GUI Controls for Input Design  Spin (Spinner) Box  A spin box is a screen based control that consists of a single-line text box followed immediately by two small buttons  The two buttons are vertically aligned  Top button has an arrow pointing upward and the bottom button has an arrow pointing down 40 Input Design and Prototyping GUI Controls for Input Design  Spin (Spinner) Box  This control allows the user to enter data directly into the associated text box or to select a value by using the mouse to scroll (or “spin”) through a list of values using the buttons  The buttons have a unit of measure associated with them  When the user clicks on one of the arrow buttons, a value will appear in the text box  The value in the text box is manipulated by clicking on the arrow buttons • The upward pointing button will increase the value in the text box by a unit of measure; whereas the downward pointing button will decrease the value in the text box by the same unit of measure 41 Input Design and Prototyping GUI Controls for Input Design  Spin (Spinner) Box  When to Use Spin Boxes For Input:  A spin box is most appropriately used to allow the user to make an input selection by using the buttons to navigate through a small set of meaningful choices or by directly keying the data value into the textbox  The data values for a spin box should be capable of being sequenced in a predictable manner 42 Input Design and Prototyping GUI Controls for Input Design  Spin (Spinner) Box  Suggested Guidelines for Spin Boxes:  Spin boxes should contain a label or caption that clearly identifies the input data item • This label should be located to the left of the text box or leftaligned immediately above the text box portion of the control  Spin boxes should always contain a default value in the text box portion of the control 43 Input Design and Prototyping How to Prototype & Design Computer Inputs  Step 1: Review Input Requirements   The design unit DFDs depict inputs to be designed  These inputs can are represented as data flows that connect external entities to processes Review the required attributes of data inputs  For each attribute, the designer must identify an appropriate caption or label they will use to clearly identify to the user the attribute appearing on the screen  The size and edit mask (or format) of the attribute must be predetermined 44 Input Design and Prototyping How to Prototype & Design Computer Inputs  Step 2: Select the GUI Controls  To choose the correct control for our attributes, you must examine the possible values for each attribute 45 Input Design and Prototyping How to Prototype & Design Computer Inputs  Step 3: Prototype the Input Screen     This step involves developing prototype screens for the user to review and test  Their feedback may result in the need to return to steps and to add new attributes and address their characteristics When prototyping input screens, it is important to actually let the user exercise or test the screens  Part of that experience should involve demonstration on how the user may obtain appropriate help or instructions Prototypes should demonstrate to the user how security will be handled Prototypes should demonstrated how error handling with be accomplished 46 Input Design and Prototyping 47 Input Design and Prototyping (b) (a) 48 Input Design and Prototyping (a) (b) 49 Input Design and Prototyping 50 Input Design and Prototyping How to Prototype & Design Computer Inputs  Step 4: If Necessary, Design or Prototype the Source Document    If a source document will be used to capture data, we must also design that document The source document is for the system user  In its simplest form, the prototype may be a simple sketch or an industrial artist's rendition A well-designed source document will be divided into zones  Some zones are used for identification; these include company name, form name, official form number, date of last revision (an important attribute that is often omitted), and logos 51 Input Design and Prototyping How to Prototype & Design Computer Inputs  Step 4: If Necessary, Design or Prototype the Source Document  A well-designed source document will be divided into zones (continued)  Other zones contain data that identifies a specific occurrence of the form, such as form sequence number (possibly preprinted) and date  The largest portion of the document is used to record transaction data • Data that occurs once and data that repeats should be logically separated 52 Input Design and Prototyping How to Prototype & Design Computer Inputs  Step 4: If Necessary, Design or Prototype the Source Document  A well-designed source document will be divided into zones (continued)  Totals should be relegated to the lower portion of the form because they are usually calculated and, therefore, not input  Many forms include an authorization zone for signatures  Instructions should be placed in a convenient location, preferably not on the back of the form 53 Input Design and Prototyping Summary     Introduction Methods & Issues for Data Capture & Input GUI Controls for Input Design How to Prototype & Design Computer Inputs 54 ... require handwriting recognition 13 Input Design and Prototyping Methods & Issues for Data Capture & Input  System User Issues for Input Design   Inputs should be as simple as possible and designed... called repository-driven programming 21 Input Design and Prototyping 22 Input Design and Prototyping 23 Input Design and Prototyping GUI Controls for Input Design  Text Box     A text box consists... machine-readable format into the computer Input Design and Prototyping Methods & Issues for Data Capture & Input  Modern Input Methods: Batch versus On-Line Inputs  Input methods can be broadly classified