The User Experience design sprung out of WWII—in Aerospace engineering.

The Design Process

The “Double Diamond” Process

First Round of Going Broad

• Explore the problem space (what are you users trying to do? why? why is it hard?)
• Decide what to fix (what is the most high impact problem?)

Second Round of Going Broad

• Test potential solutions (does this fix the problem?)
• Refine final solution (do all users understand this? can they use them?)

Usability Heuristics

Usability Heuristics is a set of principles used in User Experience design to identify problems and potential solutions.

Goal: understand the user.

Find out…

• Motivation
• Context
• Deeper need?

The goal of user interviews is to understand the user even if they know what they want!

Good User Interviews

• Make person feel welcome/safe/appreciated

• Ask open-ended “questions”

  • Describe a time that…
  • Tell me more about..

• Leave space: awkward silences (not too awkward)

• Really listen!; repress the urge to think of what you want to say next

• Repeat statements back to people

utility elicitation is the process to go from Rational Preferences to a utility function. Its a bad idea to use money to do this, because money is not linear.

Consider the best and worst possible events:

\begin{equation} \overline{S}, \underline{S} \end{equation}

We assign the best event to have utility \(1\), and worst to have utility \(0\):

\begin{equation} \begin{cases} U(\overline{S}) = 1 \\ U(\underline{S}) = 0 \end{cases} \end{equation}

Given some test event now \(S\), we try to find the \(p\) such that we can set up a lottery:

quadratic utility

\begin{equation} U(x) = \lambda x - x^{2} \end{equation}

where, \(\lambda>0\) controls risk aversion: as risk increases, utility increases concavely, then eventually utility falls

exponential utility

\begin{equation} U(x) = 1 - e^{-\lambda x} \end{equation}

where \(\lambda >0\) controls risk aversion. This is usually not plausible as utility because people’s utility doesn’t grow exponentially ever

power utility

see power utility

Take the utility function from a bunch of POMDPs and combine them together using a fusion function.

\begin{equation} U^{*}(b,a) = f(U^{*}(b_1, a) … U^{*}(b_{n}, a) \end{equation}

where \(f\) can be sum or min. The overall belief \(b\) is simply \(B_1 \times … \times B_{n}\), which combines all beliefs together.