Introduction to computer science dessalegn Mequanint Yehuala Foreword

Introduction To Computer Science
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Learning Activity : Search Engines 
Search Engines
Search engines are software tools that search documents for specified keywords and returns
a list of the documents where the keywords were found. A search engine is a general class of
programs, however, the term is often used to specifically describe systems like Google, Bing
and Yahoo search that enable users to search for documents on the World Wide Web.
Search engines are special sites on the Web that are designed to help people find
information stored on other sites. There are differences in the ways various search engines
work, but they all perform three basic tasks:
1.
They search based on words
2.
They keep an index of the words they find, along with where they find them.
3.
They allow users to look for words or combinations of words found in that
index.
Millions of people around the world use search engines almost on regular basis. The benefits
of search engines to both individuals and society is huge. They have made the web a very
critical resource repository of our time. They are the most popular and widely used tool to find
information online.
Trends in Internet Use
The Internet of Things
The term Internet of Things(IoT) has no single universal definition. The definition in [4,5] have
been picked just for their relative simplicity and clarity. The term Internet of Things generally
refers to scenarios where network connectivity and computing capability extends to objects,
sensors and everyday items not normally considered computers, allowing these devices to
generate, exchange and consume data with minimal human intervention.
It can also be defined as the network of physical objects—devices, vehicles, buildings and
other items embedded with electronics ,software, sensors, and network connectivity—that
enables these objects to collect and exchange data. The Internet of Things allows objects
to be sensed and controlled remotely across existing network infrastructure, creating
opportunities for more direct integration of the physical world into computer-based systems,
and resulting in improved efficiency, accuracy and economic benefit.
When IoT is augmented with sensors and actuators, the technology becomes an instance of
the more general class of cyber-physical systems, which also encompasses technologies such
as smart grids, smart homes, intelligent transportation and smart cities. Each thing is uniquely
identifiable through its embedded computing system but is able to interoperate within the
existing Internet infrastructure. Experts estimate that the IoT will consist of almost 50 billion
objects by 2020.

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