Closed-circuit television

Closed-circuit television (CCTV), also known as video surveillance, is the use of video cameras to transmit a signal to a specific place, on a limited set of monitors. It differs from broadcast television in that the signal is not openly transmitted, though it may employ point to point (P2P), point to multipoint, or mesh wireless links. Though almost all video cameras fit this definition, the term is most often applied to those used for surveillance in areas that may need monitoring such as banks, casinos, airports, military installations, and convenience stores. Videotelephony is seldom called "CCTV" but the use of video in distance education, where it is an important tool, is often so called.

In industrial plants, CCTV equipment may be used to observe parts of a process from a central control room, for example when the environment is not suitable for humans. CCTV systems may operate continuously or only as required to monitor a particular event. A more advanced form of CCTV, utilizing digital video recorders (DVRs), provides recording for possibly many years, with a variety of quality and performance options and extra features (such as motion detection and email alerts). More recently, decentralized IP cameras, some equipped with megapixel sensors, support recording directly to network-attached storage devices, or internal flash for completely stand-alone operation. Surveillance of the public using CCTV is particularly common in many areas around the world. In recent years, the use of body worn video cameras has been introduced as a new form of surveillance.

CCTV-4

CCTV-4 中文国际 (Chinese: 中国中央电视台中文国际频道; pinyin: Zhōngguó zhōngyāng diànshìtái zhōngwén guójì píndào) is a 24-hour Chinese international channel. It is one of six China Central Television channels that broadcasts outside of the People's Republic of China.

This channel contains a variety of programs including documentaries, music, news, drama series, sports and children shows for the People's Republic of China, mainland China, Hong Kong, Macau and Republic of China.

History

CCTV-4 was officially launched by President Yang Shangkun at President Palace of the People's Republic of China in Beijing in 1992. It started as a six-hour Chinese international channel.

The programming of CCTV-4 initially consisted of a mixture of English and Chinese programming. English broadcasting stopped with the introduction of the English language channel CCTV-9 in September 2000. Select CCTV-4 programs were also broadcast in Cantonese until 2007, since when the channel has been broadcast in Mandarin Chinese only.

Facebook

Facebook is a corporation and online social networking service headquartered in Menlo Park, California, in the United States. Its website was launched on February 4, 2004, by Mark Zuckerberg with his Harvard College roommates and fellow students Eduardo Saverin, Andrew McCollum, Dustin Moskovitz and Chris Hughes. The founders had initially limited the website's membership to Harvard students, but later expanded it to colleges in the Boston area, the Ivy League, and Stanford University. It gradually added support for students at various other universities and later to high-school students. Since 2006, anyone who is at least 13 years old was allowed to become a registered user of the website, though the age requirement may be higher depending on applicable local laws. Its name comes from the face book directories often given to American university students.

After registering to use the site, users can create a user profile, add other users as "friends", exchange messages, post status updates and photos, share videos, use various apps and receive notifications when others update their profiles. Additionally, users may join common-interest user groups, organized by workplace, school or college, or other characteristics, and categorize their friends into lists such as "People From Work" or "Close Friends". Also users can complain or block unpleasant people. Facebook had over 1.18 billion monthly active users as of August 2015. Because of the large volume of data users submit to the service, Facebook has come under scrutiny for their privacy policies. Facebook, Inc. held its initial public offering in February 2012 and began selling stock to the public three months later, reaching an original peak market capitalization of $104 billion. On July 13, 2015, Facebook became the fastest company in the Standard & Poor's 500 Index to reach a market cap of $250 billion. Following its Q3 earnings call in 2015, Facebook's market cap soared past $300 billion.