Civil Engineering Reference
In-Depth Information
In addition to voice communication, the cell phone/smart phone provides a
variety of functionalities, including:
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diary, email, to-do list and so on;
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work coordination systems (often Web-based);
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Web access to applications found on the mobile or desktop computer; and
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applications (refers to smartphone Apps).
The laptop and smart phone seem to be evolving in a convergent manner. An
interesting example of this is the Apple iPad, which integrates many traditional
laptop capabilities and many traditional smart phone capabilities in an almost
pocket size format.
In general, the laptop and smart phone can be regarded as system and person
centered, respectively. How, then, should embedded devices, such as sensors,
actuators and control boxes be understood?
These devices are most often used to deliver information to:
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partially autonomous systems of embedded devices for the purposes of, for
example, control, maintenance, logistics, production planning and quality;
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governing applications (those used at the laptop level); and
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location and time-specific information to people, organizations and systems
concerned with, for example, operations, engineering, maintenance and logistics.
An example of mobile and pervasive computing is shown in Figure 3.1. The
interactions that will take place between different human workers and different
systems can be imagined.
It is important to understand that such environments are dynamic because
people are dynamic and come and go, faulty or old devices are replaced, new devices
are introduced, new constraints are imposed due to customers' orders, new laws are
introduced and so on. A critical part of a well-functioning mobile and pervasive
system is the capacity to adapt to dynamic environments.
3.3 Communication basics
The OSI (open systems interconnection) communication stack (ISO, 1994) is used
to describe the basics of communication for mobile and pervasive computing
(Figure 3.2).
The discussion starts with the physical layer, working up to the presentation
layer. As mobile and pervasive usage is being targeted, the physical layer is a radio
link.
3.3.1 Radio standards and available technologies
A summary of some available radio standards and commercially available technol-
ogies operating in the free ISM bands is presented in Table 3.1. Many other
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