1. MBI 630: Week 11 Interface Design
12/2/2018

2. Week 11: Designing Interfaces and Dialogues
Here, Interface does not mean just Graphical User Interface; rather it’s more general conversation between the system and the users, how users navigate through the system, what feedback the system should provide, help functions, etc.
We have finished Database design. There are some more items to be designed before actually start programming: Input forms, output reports, interfaces, and structure of the system software.
Design specifications are major deliverable and contain three sections
Narrative overview
Sample design
Testing and usability assessment

3. Styles of User Interfaces
User interface design is the specification of a conversation between the system user and the computer.
This conversation generally results in either input or output -- possibly both.

4. Interaction Methods and Devices
Command Language Interaction
Menu Interaction
Object-Based Interaction (GUI)
(Natural Language Interaction)
User interface design is the specification of a conversation between the system user and the computer.
There are two issues to be determined: Methods of Interacting (or navigating through the system) and Contents of dialog.
Interacting methods are how the system users convey instructions and data to the system.
Dialogs are how the system responds (feeds back) to the users.
User-type and the degree of user-friendliness have correlation. For example, casual users require the most user friendly interfaces. You cannot expect them to handle command interfaces. On the other hand, dedicated users want the performance of interfaces, meaning that minimizing key-strokes, movement of mouth should be minimized. In such a case, user-friendliness is not so important
A dedicated system user is one who will spend considerable time using specific programs. This user is likely to become more comfortable and familiar with the terminal or PC's operation.
The casual system user may only use a specific program on an occasional basis. This user may never become truly comfortable with the terminal or the program.

5. Controlling Data Input
One objective of interface design is to reduce data entry errors
Role of systems analyst is to anticipate user errors and design features into the system’s interfaces to avoid, detect and correct data entry mistakes
Table 11-8 (p. 410) describes types of data entry errors
Table 11-9 (p. 411) lists techniques used by system designers to detect errors

6. Providing Feedback Status Information Prompting Cues
Keeps users informed of what is going on in system
Displaying status information is especially important if the operation takes longer than a second or two
Prompting Cues
Best to keep as specific as possible
Error and Warning Messages
Messages should be specific and free of error codes and jargon
User should be guided toward a result rather than scolded
Use terms familiar to user
Be consistent in format and placement of messages
Providing feedback to the users has several patterns.
Status Information: e.g., downloaded 10.0 MB or 1% of 1GB
Prompting Cues: e.g., Installation complete, reboot your computer.
Error and Warning Messages: e.g., Error 404: File not found
Providing Help: help menus, wizards, tutorials, Context-Sensitive Help

7. Providing Help Place yourself in user’s place when designing help
Guidelines
Simplicity
Help messages should be short and to the point
Organization
Information in help messages should be easily absorbed by users
Demonstrate
It is useful to explicitly show users how to perform an operation

8. Designing Dialogues Dialogue
Sequence in which information is displayed to and obtained from a user
Primary design guideline is consistency in sequence of actions, keystrokes and terminology
Dialogue Diagram (Fig , pp )
A formal method for designing and representing human-computer dialogues using box and line diagrams
Consists of a box with three sections (Fig , p. 418)
Top: Unique display reference number used by other displays for referencing dialogue
Middle: Contains the name or description of the display
Bottom: Contains display reference numbers that can be accessed from the current display
Designing the Dialogue Sequence
Define the sequence
Have a clear understanding of the user, task, technological and environmental characteristics

9. Sample Dialogue Diagram
Figure 11-18
You could use Figure (p. 420) as an example for your Dialogue diagram; one thing I don’t like the example is that they give the log-in screen the number 0, and Main menu 1, then each functions start from #2 - #5. Considering the numbering of DFDs, I prefer having Main Menu #0, and each function start from #1. That puts Log-in page to an awkward position, but we could use some special markings (like, not all pages require logins, so it could be optional, or #0.5 or something – hope it’s not a negative number…)