In our increasingly mobile world the ability to access information on
demand at any time and place can satisfy people's information needs as
well as confer on them a competitive advantage. The emergence of
battery-operated, low-cost and portable computers such as palmtops and
PDAs, coupled with the availability and exploitation of wireless
networks, have made possible the potential for ubiquitous computing.
Through the wireless networks, portable equipments will become an
integrated part of existing distributed computing environments, and
mobile users can have access to data stored at information servers
located at the static portion of the network even while they are on the
move.
Traditionally, information is retrieved following a request-response
model. However, this model is no longer adequate in a wireless computing
environment. First, the wireless channel is unreliable and the bandwidth
is low compared to the wired counterpart. Second, the environment is
essentially asymmetric with a large number of mobile users accessing a
small number of servers. Third, battery-operated portable devices can
typically operate only for a short time because of the short battery
lifespan. Thus, clients are expected to be disconnected most of the
time.
To overcome these limitations, there has been a proliferation of
research efforts on designing data delivery mechanisms to support
wireless computing more effectively. Data Dissemination in Wireless
Computing Environments focuses on such mechanisms. The purpose is to
provide a thorough and comprehensive review of recent advances on
energy-efficient data delivery protocols, efficient wireless channel
bandwidth utilization, reliable broadcasting and cache invalidation
strategies for clients with long disconnection time. Besides surveying
existing methods, this book also compares and evaluates some of the more
promising schemes.
