Part C: User Interface Flashcards
- Usability definition (max 6 points)
ISO 9241-11:1998 provides “guidance on usability” as part of the statement on “Ergonomic requirements for office work with visual display terminals”. What are the key elements of this standard’s definition of “usability”?
ISO DSI 9241-11 defines usability as:
- the effectiveness, efficiency and satisfaction
- with which specified users
- can achieve specified goals
- in particular environments
The focus on specifics implies no generalization
- Usability attributes (max 5 points)
There are two elements of “Usefulness” when considering the acceptability of software products: “Utility” concerns the functionality or “what” the software delivers while “Usability” represents how well the software delivers this functionality. List the principal usability attributes.
Attributes:
- Easy to learn
- Easy to use
- Easy to remember
- Few errors
- Subjectively pleasing
- Website usability - navigation (max 5 points)
What aspects of usability should be considered when designing the navigation of a website?
Answer:
- Embrace Predictability
- Keep it Simple
- Don’t Overdo Minimalism
- Keep it Consistent
- Clear Hierarchical Structure
- Make it Manageable
- Include a search bar
- The cycle of interaction (max 4 points)
What are the key concepts in the “cycle of interaction”? You may use a diagram to present your answer.
Gulf of Evaluation - What is the current state of the system?
Gulf of Execution - How do I use the system?
The two gulfs are closely related to Norman’s Seven Stage of Action Evaluation: - Deciding the goal - Intention to act. - Sequence of actions. - Execution of the action.
Execution:
- Perception of the state of the world.
- Interpretation of this perception
- Evaluating the outcome.
- Users and requirements (max 4 points)
“User centred design” rightly places an emphasis on addressing user needs in designing a software system but what difficulties do users present as sources of requirements?
Poor witnesses when asked out of context - For HTA (Hierarchical Task Analysis - For use case modelling & OOA - Narrow specialisations Hawthrone effect when being observed - Motivated due to attention - Overly helpful - Doing things “properly” Not domain or subject experts - “We don’t know what we want” - “But it IS NOT this!!!” - Resented by the uninvolved rest
- Legacy system as a requirements filter (max 6 points)
With the aid of a diagram explain why the existence of a pre-existing or legacy system can distort the users’ view of the requirements for a new system.
nope
- Discount usability engineering (max 4 points)
Usability engineering can be a very expensive activity. Nielsen has suggested the adoption of “discount usability engineering” which defines a minimal set of activities. What does he propose?
User & task observation - Observe users - Keep quiet - Let users work without interference Prototyping scenarios - Simulate the interface - Aim for quick & frequent feedback Simplified thinking aloud - Capture why user are doing what they are doing - While they are doing it Heuristic evaluation - More than one evaluator - Pluralistic walkthroughs, multi-viewpoint (Faulkner:)
- Usability heuristics (max 4 points)
What is meant by a heuristic? There are a great many usability heuristics – provide 6 example usability heuristics.
“Heuristics are the strategies derived from previous experiences with similar problems.” - Wikipedia
Usability Heuristics - Neilsen
- Simple and natural dialogue
- Speaking the User’s language
- Minimise User memory load
- Consistency
- Feedback
- Clearly marked exits
- Shortcuts
- Good error messages
- Prevent errors
- Help & Documentation
- Integrating usability engineering (max 5 points)
Usability engineering is a specialist aspect of software engineering but it is recognized that the associated activities should not be treated as a stand-alone process or phase. How can usability engineering be integrated with other software development activities?
In the same way as testing is performed during the continous work, usability engineering would also fit in the same manner? A guess.
- Task analysis (max 4 points)
There are four principal areas of investigation in user-related task analysis. What are these? For each are provide two questions that should be considered.
Inputs:
- What information is needed?
- What are the information sources?
- What is the availability of the information?
- What error might occur?
- What initiates the task?
Outputs:
- What are the performance criteria?
- What happens to the output?
- How does the task performer get feedback?
The Transformation:
- What is the nature of the decision-making?
- What strategies exist for decision-making?
- What skills are needed?
- What interruptions might occur?
- And when?
The context:
- How often is the task done?
- Does the task depend upon any other task?
- What is the workload - normal & abnormal?
- What control does the task performer have over workload?
46. State charts (max 5 points) In general terms, how would you define the state of an object? What is the purpose of a state chart in UML? Make sure your answer addresses both a class view and an object view.
In general terms, how would you define the state of an object?
A state is a situation where the system is waiting for an action to take place.
What is the purpose of a state chart in UML? “The most important purpose of a Statechart diagram is to model the lifetime of an object from creation to termination.”
Modeling the states is a useful way to communicate within the team how the system should function. You can talk all you want about what the system should do and how it should look, but a rigorous blueprint of how the system should actually function is vital for everyone to be on the same page.
The class view can be used as a more compact overview of the system and how it functions on a higher level. The object view on the other hand presents more detail, and is useful for the nitty-gritty design decisions.
- Constructing a state transition table (STT) (max 4 points)
What is the basic structure of an STT? From an analysis perspective, what are the three possible answers – in generic terms – wherever there is an empty cell in the STT matrix?
State 1 State 2 State 3
Event 1 Transition 1 Transition 2 Transition 3
Event 2 Transition 4 Transition 5 Transition 6
Event 3 Transition 7 Transition 8 Transition 9
- Constructing a state chart (max 4 points)
What is the basic structure of a state chart?
A state is represented as a rounded rectangle, labeled with the state name.
Transitions (or actions) are represented as a labeled arrow.
There can also be an initial state, represented by a solid black circle, and an end state represented by a circle with a black dot inside.
