What is Human Computer Interaction?
HCI is the design, implementation and evaluation of user interfaces.
Good design is a pleasure to use; it increase efficiency and prodcutivity. Whereas bad design can be frustrating and in extreme cases can even costs lives.
Design using Prototypes
Prototyping is the single most important strategy for effective design. It should focus on the goals and not get stuck with some (current fad) design idea.
Design prototype as like software prototypes. Quick approximation of the idea, that helps collect feedback and iterate towards the final (design) goal. They let the users experience what the final product might look like (feel), work like (implementation) or the UX (role).