"The Concept of computers as things that you walk up to, sit in front of and turn on will go away. In fact, our goal is to make the computer disappear. We are moving towards a model we think of as a 'personal information cloud'. That cloud has already begun to coalesce in the form of the Internet. The Internet is the big event of the decade [...]. We'll spend the next 10 years making the Net work as it should, making it ubiquitous."
Frank Casanova, director of Apple Computer Inc.'s Advanced Prototyping Lab

Thus, the goal of ubiquitous computing is to move computers away from the central focus of the user's attention (and into cupboards, behind walls, etc.), where they are used subconsciously, to enhance existing tools or communications. This whole new way of interfacing with computers, networks (such as the Internet) and the like, offers many exciting possibilities;

	"It can drag interactivity away from technological fascination and wizardry into the realm of human experience and action. What is being designed is no longer a medium or a tool in the traditional sense, but something far more intangible, embedded in a continuously changing environment where everything is connected to everything else."
from [RIJK94]

This chapter will give an introduction to the concept of Ubiquitous Computing (UC), which we will have a look at in section 4.2. Section 4.3 is about the concept of "Calm Technology" (CT) which extends the notion of UC and uses its principles to create technology that leads to calmness and comfort by making use of the centre and the periphery of a user's attention. Section 4.4 is about a concept called "Augmented Reality" which also makes heavy usage of the principles of UC, and which is about enhancing a user's perceptions with computation and enhancing a physical object (such as a user's desk) using computation.

At the end of this chapter, besides introducing these concepts, it should have become clear why it has been decided to include them in this paper. As has been pointed out in chapter three, we are in need of new ways to interface with our computers, with the online market place (for now: the Internet) and we need ways to cope with all the information that most of us feel overwhelmed with.
The two concepts of UC and CT seem to have the potential to deal with many issues in this area. Some, like Marc Weiser, are even convinced that Ubiquitous Computing will be the next major wave in computing:

	"The defining words [for the third wave in computing] will not be "intelligent" or "agent"1, but rather "invisible" and "calm" and "connection". [...] The first wave of computing, from 1940 to about 1980, was dominated by many people serving one computer. The second wave, still peaking, has one person and one computer in uneasy symbiosis, staring at each other across the desktop without really inhabiting each other's worlds. The third wave, just beginning, has many computers serving each person everywhere in the world. I call this last wave 'ubiquitous computing'. "
from [WEIS96]