System Design 1.6 Flashcards
What are the advantages of command line/driven interfaces
Some commands can be entered quickly + precisely once the user is proficient/ expert
Can run on very low spec computers with bad graphical facilities
Can be used over slower connections e.g. modems (as there is very little data being transferred)
Complex commands are often made available that wouldn’t be in a graphical user interface
What are the disadvantages of commands line/driven interfaces
Not easy to guess the command that has to be entered
Can be difficult to learn
Not an attractive interface, rather unfriendly
What are the advantages of Graphical user interfaces (GUI)
User friendly, inexperienced users can often guess what they want to do. (No need to remember complex commands)
More intuitive/easy to learn
Windows: can be resized, multiple can be viewed at once etc.
Icons: small images to represent options (human brain can recognise images quicker than words)
Menus: easy to see all options in a pull-down menu
Pointer: natural way to point at things they want (point and click)
Cut and paste between applications
Similarity between applications
Help, undo, tutorials etc.
What are the disadvantages of a Graphical User Interface (GUI)
Can ‘get in the way’. E.g. having to select several options to perform a task that would otherwise take seconds I’m a command driven interface
Needs a more powerful computer than command driven
What are the advantages of a menu driven interface
E.g. cash point screen
Advantages:
Very easy to learn (selection required only)
Limited options, so user will not get confused
No need for a keyboard (physical or virtual)
What are the disadvantages of a menu driven interface
E.g. cash point screen
Disadvantages
Only suitable where there are few/very limited options
What are the advantages of form dialogue
Rather like a paper form (therefore intuitive)
Specific input fields to fill in
Can go back and make changes before form is submitted
Undo and ‘are you sure?’
Includes validation so only some entries are allowed
Often able to reduce input options using radio buttons, drop-down lists.
What are the disadvantages of form dialogue
Good on-screen help may be required
Layout is important
Ensure form is uncluttered
What are touch screens
Touch screens are a feature of many new devices e.g. phones
They take advantage of gestures that can make the user interface easier to use
E.g. swipes, pinch to zoom, long press etc.
What is haptic feedback
An extension of touch interface, uses sensations such as vibration, pressure, pain, temperature, etc. To give feedback
E.g. mobile phone or games controller
More advanced systems may use full body suits for more realism
Haptic feedback may be used go make virtual reality feel more real e.g. to make it feel as if we are really touching the door, picking up the ball etc.
What is virtual reality
VR uses headsets to immerse the user in a virtual world where they interact by moving their bodies
Sensors track the users movement and translate it into changes in the world the user is seeing
Many people are affected by motion sickness when using VR. However this may eventually be resolved by improvements in the use of haptic feedback
What is augmented reality (AR)
Similar to VR, however works by overlaying computer graphics over a view of the real world
E.g. possible to have meetings with people in AR to make it seem as if they are sat with you, however they are sat at the other side of the world.
What is a Natural language interface
E.g. alexa, siri
No need to follow a particular structure to words entered
Communicate with computer as you would another person
What are the problems facing natural language interface designers?
Simple speech/handwriting recognition
Ambiguity - many sentences have multiple meanings
Unclear input - poor handwriting, unclear speech (e.g. mumbling, accent, speech impediment)
Understanding - the computer really needs to understand the topics being discussed. Currently impossible but ‘general AI’ is improving all the time
Statistical analysis - often AI combines with probabilty/ statistics for the computer to try to resolve ambiguity or unclear input e.g. which meaning is likely to be most correct
How can sound be used when designing interfaces in order to make it easier for the user to use their particular interface?
To indicate a problem (e.g. an error has occurred)
To let the user know that a lengthy task has finished
To indicate that an event has happened e.g. email received
Particularly useful for partially sighted or blind people e.g. speech synthesis
