Image Processing Reference
In-Depth Information
3.1 Third Era of Computing
Things are changing continuously in the world of computers. Everything started with the mainframe
era: some years ago, these huge devices were widely deployed, for example, within universities.
Lots of users made use of a single mainframe computer which they had to share among them-
selves.hecomputationpowercametogetherwithahighcostandahugemachinerequiringalotof
maintenance.
Technology advanced as it was predicted by Moore's law and we stepped into the second era of
computers. It is a period that is still present today, but which is slowly approaching its final part. It is
the era of the personal computers, cheaper and smaller, and increasingly affordable. Quite often, the
average user has access to and makes use of more than one computer, these machines being present
now in almost any home and work place.
But, in this familiar environment, things are starting to change and the third era of computing
gains more and more terrain each day. Let us take a look at the main trends today. The technology
advancements cause the personal computers to become smaller and smaller. he desktop computers
tend to be replaced by laptops and other portable devices. What used to be a “regular” cell phone
advanced to quite a sophisticated device (incorporating, for example, a digital camera and a personal
digital assistant (PDA) having increasing communication capabilities, etc.).
The main factor that is influencing the new transition is the availability of wireless communica-
tion technology []. People are getting rapidly used to wireless communicating devices due to their
independence from fixed machines. he success and availability of the Internet brought even more
independence to the user: the data could now be available regardless of the physical location of its
owner.
The advancements in technology did not stop here: the processors became small and cheap enough
to be found now in almost any familiar device around us, starting with an everyday watch and ending
with (almost) any home appliance we own. he new efforts nowadays are to make these devices “talk”
to each other and organize themselves into ad hoc networks to accomplish their design goal as fast
and reliably as possible.
This is, in fact, the third computer age envisioned two decades ago by Mark Weiser []. Several
names such as ubiquitous computing, pervasive computing, ambient intelligence, invisible comput-
ing, disappearing computer, Internet of things, etc. were created to indicate different aspects of the
new computing age (Mark Weiser himself defined it as “the calm technology, that recedes into the
background of our lives”).
The ubiquitous computing world brings a reversed view on the usage of computing power: instead
of having lots of users gathered around the mainframe computer, now each user is using the services
of several embedded networks. he user is in the middle of the whole system, surrounded by an invis-
ible intelligent infrastructure. he original functionality of the objects and application is enhanced,
and a continuous interaction is present in a large variety of areas of daily life.
So what is the next step? Technology will continue to advance and issues as miniaturization,
number of features per device, battery lifetime and available connectivity everywhere, numbers of
available sensors, etc. will be increasingly solved or at least improved. Computers (in various forms
and shapes) start getting more and more accessories as sensors and “actuators.” Getting used to the
acting feature of these devices and designing applications specifically for a large number of devices
to “do” things together will probably be a step forward in the development of embedded systems as
we know them.
3.2 What Are Wireless Sensor Networks?
So what are wireless sensor networks and where is their place in this new environment that starts
“growing” around us?
