Design, Prototyping and Construction

• The product emerges iteratively through repeated design-evaluation-redesign cycles.
• prototypes facilitate the process.

There are two main parts of design:

• conceptual design.
• concrete desgin.

Prototyping

• Users can't tell you what they want, but when using a prototype that can say what they dislike.

Prototype

A prototype is a manifestation of a design that allows stakeholders to interact with it and to explore it's suitability.

• It is limited: usually focused on one product characteristic while de-emphasizing other characteristics.
• A prototype does not have to fit a form: can be paper-based, or wooden block to complex software.

Why Prototype ?

• Useful to discuss ideas with stakeholders.
  • Allows more effective communication.
• The activity of building prototypes encourages reflection about the design.
• Support in choosing between design alternatives.
  • can help test technical feasibility.
  • can clarify vague requirements.

Prototypes can be distinguished into:

• Product Prototypes
• Service Prototypes
  • Interactions with people play a part in this type of prototype.

Low-Fi Prototyping

Lo-Fi Prototype

A low-fidelity prototype does not look much like the final product or provide the same functionality. Low fidelity prototypes are useful because they tend to be simple, cheap and quick to produce. They are also flexible (due to low cost) and encourage exploration and modification.

Storyboarding

Storyboarding is an example of low-fi prototyping. it consists of a series of sketches or scenes showing how a user can perform a task using an interactive device.

Sketching

low-fi prototyping often relies on hand-drawn sketches. These sketches can be done as a part of storyboarding or drawing by hand the interface that is being designed.

Index Cards

Using index cards (small cardboard pieces) is another technique to prototype interaction. Each card represents one element of the interaction. The card can be for example: a screen, or just an icon, menu or dialog exchange. In user evaluations, the user can step through the cards pretending to perform the task using the cards.

Wizard of Oz

• For software based prototypes

A user interacts with the software prototype, and the response from the software is simulated by a human operator.

For example:

1. tester enters input "Is the earth flat?"
2. hidden human operator manually shows on screen "NO"

this technique is used for AI based products.

Hi-Fi Prototypes

Hi-Fi Prototypes

A hi-fi prototype looks more like the final product and usually involves more functionality than a low-fi prototype. There is a continuum between low to high fi. It is common for prototypes to evolve through various stages of fidelity.

Hi-fi prototypes can be developed for software in particular following Opportunistic System Development which aims to use as much existing open-source software or development kits, to reduce time and costs.

• a prototype should be built with key-issues in mind. Because the questions that any prototype can answer are limited.

two common properties that are traded off against each other are:

• functionality depth:
  • aka: vertical prototyping
  • lots of detail for few functions
• functionality breadth:
  • aka: horizontal prototyping
  • lots of functions without much detail

There are two techniques to go from prototype to product:

• evolutionary prototyping:
  • prototype becomes the product itself
  • advantage: speed to market
  • disadvantage: technical debt must be solved. (unless good engineering)
• throwaway prototyping
  • prototype is thrown away.
  • learnings are used to make the product from scratch.
  • advantage: may lead to good engineering.
  • disadvantage: slower and expensive.

Construction

Building Prototypes:

• use resources such as APIs, SDKs to support development.