We were on the lookout for ice.
I was in a 32 foot sailing yacht with writer and explorer Tristan Gooley, undertaking a
double-handed sail from Scotland through the Faroes up to 66 33 45.7 N and the midnight
sun. Now sailing out of the Arctic Circle we were approaching Iceland from the north, heading
for the Denmark Straits, where ice flowed south. The Admiralty Pilot warned of bergs but the
ice charts we had sailed with were over a week old. We needed an update.
Welcome to the world of wireless communications and the logical extension
to the broadband architectures that are emerging as the future of the
industry. No aspect of communications will be untouched by the wireless
interfaces;no part of our working environment will be left untouched either.
As the world changes and the newer technologies emerge, we can expect to
see more in the line of untethered communications than in the wired inter-
faces.
Fun. We (your authors) wanted a word to describe our ultimate goal for this book, as well as a word
we hope you (our reader) will use to describe it, and that’s the one we chose. There are others goals,
of course, but in the end, when you’ve finished the book, we’re hoping you’ll have enjoyed the
activities described in these pages.
Many books use the Introduction to explain exactly what the book is about, what the reader will
learn, what the reader needs (a skill or maybe an item or piece of software), and what the reader
will be left with when that last page is completed. And this Introduction will do those things, but …
hopefully it’ll make you excited to get started.
Sound is simply an airborne version of vibration. The air which carries sound is a mixture
of gases. In gases, the molecules contain so much energy that they break free from
their neighbors and rush around at high speed. As Figure 1.1(a) shows, the innumerable
elastic collisions of these high-speed molecules produce pressure on the walls of any
gas container. If left undisturbed in a container at a constant temperature, eventually the
pressure throughout would be constant and uniform.
The past decade has seen an explosion of machine learning research and appli-
cations; especially, deep learning methods have enabled key advances in many
applicationdomains,suchas computervision,speechprocessing,andgameplaying.
However, the performance of many machine learning methods is very sensitive
to a plethora of design decisions, which constitutes a considerable barrier for
new users. This is particularly true in the booming field of deep learning, where
human engineers need to select the right neural architectures, training procedures,
regularization methods, and hyperparameters of all of these components in order to
make their networks do what they are supposed to do with sufficient performance.
This process has to be repeated for every application. Even experts are often left
with tedious episodes of trial and error until they identify a good set of choices for
a particular dataset.
以STC12C5A60S2單片機為控制核心,采用2.4G(JF24D)無線遙控模塊進行無線發射與接收,設計了一種雙電機遙控船模控制系統.該系統通過切換檔桿實現前進后退,方向盤左右轉動、暫停按鈕等控制直流電機的正轉、反轉、暫停,使得電機驅動的遙控船模實現前進后退、左右轉向、暫停等功能,有效解決了驅動功率小和船模之間相互干擾等問題,可廣泛應用于遙控船模領域.Using STC12C5A60S2 single-chip microcomputer as the controller and 2.4 G(JF24D)wireless remote control module for wireless transmission and reception, a dual-motor remote control ship model control system is designed. The system realizes forward and backward by switching the gear lever. The steering wheel rotates left and right and the pause button controls the forward, reverse and pause of the dc motor. The remote controller of ship model driven by the motor realizes forward and backward, left and right steering, pause and other functions. The ship model control system can effectively solve the problems of small driving power and mutual interference between ship models, and can be widely used in the field of remote controller of ship model.
