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Introduction
We can hardly imagine a world without all the electrical devices and equipment
that help us in our daily activities. Consider some of our routine daily activities.
We are awakened by the buzzer of our digital clock, use a remote control to turn on
the TV or radio to listen to the morning news and trafc reports, turn on the cof-
feemaker before stepping into the shower or take a few sips of the coffee that was
already brewed since we programed it before going to bed the night before, make
a piece of toast in the toaster or pick out a couple of eggs from the refrigerator and
x those over the stove, and turn on the computer ...