Design Process

Question	Answer
Correctness	People want interfaces to be responsive and "error-free" because they are an integral part of society.
An UI is "wrong" if..	It doesn't satisfy users needs. Core dump. Incorrect calculations.
Specification	Understandable by end users, easy to write down, revise and convert into implementations, precise enough to settle arguments and able to facilitate answering questions.
Formal languages	Formalized descriptions that clarify intentions. Provide unambiguous description of a small part of the world.
State machines	Method for formally describe interactions. Diagrams.
Finite State Machine (FSM)	An abstract representation of a system with states and transitions (events/actions).
Central tension	The bridge between the users' world, non-formal and rich, and the system's world, rigid and formalized.
Problems with FSM	Complexity of interfaces. Cannot represent some notions, e.g., timed events. Time to create/update model is not inconsequential.
Formalized descriptions	“Since a complete formalization of the properties of a large system is infeasible, the question is not whether specifications should focus on some details at the expense of others, but rather which details merit the cost of formalization.”
Non-formal languages	Have more expressive power.
Semi-formal languages	A formal language complemented by a non-formal language.
User Centred Design (UCD)	User-centred design is a process for figuring out the correct functionality of an application through semi-formal languages. It's all about understanding people, their needs and how they use your software.
UCD principles	Understand users’ needs. Design the UI first. Iterate. Use it yourself. Observe others using it.
Scenarios	Stories of people using technology, that is easier to understand by developers and users, non-formal, appropriated detailed and with variations.
Functions prioritization	Critical: Needed by early users to do something useful. Important: Required before shipping the product. Nice to Have: Nice, but unnecessary.
Usage patterns	Is certain task performed by many or few users? Is it frequent or occasional?
Designing the UI	Widgets identification. Customized or familiar ones? Attributes assignment. Model, affordances, presentation.
UI attributes	Model: what data does it need? Affordances: what can you do with it? Presentation: how does it appear in the UI?
Component distribution: Temporal	When components appear, the flow from one interface to another.
Component distribution: Spatial	Where components appear on an individual interface section. Use visual design & Gestalt principles.
Storyboards	Quick way to sketch out sequence and schematics.
Interaction Sequences	Macro-structure, convey the "big picture“ of system interaction.
Interface Schematics	Micro-structure, convey essential content, and functionality at individual steps of interaction. Includes enough detail so that someone could begin designing and implementing system logic.
Visual vocabulary	A standard set of graphical symbols and notation to describe something.
Prototypes	A limited representation of a design that allows people to interact with it and to explore its suitability.
Prototype fidelity	Faithfulness of prototype appearance and performance to final product.
Low fidelity prototype	Prototype doesn’t look much like final product, operation of the prototype may be simulated and slower.
High fidelity prototype	Prototype looks and operates like the real product.
Paper prototyping	“Usability Testing where representative users perform realistic tasks by interacting with a paper version of the interface that is manipulated by a person playing computer, who doesn’t explain how the interface is intended to work.” (Snyder, 2003, p. 4)
Wizard-of-Oz Technique (WoZ)	Evaluate unimplemented technology by using a human to simulate the response of a system.

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	Created by dcardosods about 9 years ago