Yao graph

In computational geometry, the Yao graph, named after Andrew Yao, is a kind of geometric spanner, a weighted undirected graph connecting a set of geometric points with the property that, for every pair of points in the graph, their shortest path has a length that is within a constant factor of their Euclidean distance.

The basic idea underlying the two-dimensional Yao graph is to surround each of the given points by equally spaced rays, partitioning the plane into sectors with equal angles, and to connect each point to its nearest neighbor in each of these sectors. Associated with a Yao graph is an integer parameter k ≥ 6 which is the number of rays and sectors described above; larger values of k produce closer approximations to the Euclidean distance. The stretch factor is at most , where is the angle of the sectors. The same idea can be extended to point sets in more than two dimensions, but the number of sectors required grows exponentially with the dimension.

Andrew Yao used these graphs to construct high-dimensional Euclidean minimum spanning trees.

Graph

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See also

Facebook Graph Search

Facebook Graph Search was a semantic search engine that was introduced by Facebook in March 2013. It was designed to give answers to user natural language queries rather than a list of links. The Graph Search feature combined the big data acquired from its over one billion users and external data into a search engine providing user-specific search results. In a presentation headed by Facebook CEO Mark Zuckerberg, it was announced that the Graph Search algorithm finds information from within a user's network of friends. Additional results were provided by Microsoft's Bing search engine. In July it was made available to all users using the U.S. English version of Facebook. In December 2014, Facebook changed its search features, dropping partnership with Bing, and eliminating most of the search patterns.

Development

The feature was developed under former Google employees Lars Rasmussen and Tom Stocky.

The Graph Search Features was launched in Beta January 2013 as a limited preview for some English users in the United States. Company reports indicate that the service launched to between tens and hundreds of thousands of users. As of August 2013, Graph Search is available to all English users in the US.

Internet Archive

Coordinates: 37°46′56″N 122°28′18″W / 37.7823°N 122.4716°W / 37.7823; -122.4716

The Internet Archive is a San Francisco-based nonprofit digital library with the stated mission of "universal access to all knowledge". It provides free public access to collections of digitized materials, including web sites, software applications/games, music, movies/videos, moving images, and nearly three million public-domain books. As of May 2014, its collection topped 15 petabytes. In addition to its archiving function, the Archive is an activist organization, advocating for a free and open Internet.

The Internet Archive allows the public to upload and download digital material to its data cluster, but the bulk of its data is collected automatically by its web crawlers, which work to preserve as much of the public web as possible. Its web archive, The Wayback Machine, contains over 150 billion web captures. The Archive also oversees one of the world's largest book digitization projects.

Yao

Yao or YAO may refer to:

Yao people

The Yao nationality (its great majority branch is also known as Mien; Traditional Chinese: 瑤族, Simplified Chinese: 瑶族, Pinyin: Yáo zú; Vietnamese: người Dao) is a government classification for various minorities in China. They form one of the 55 ethnic minority groups officially recognized by the People's Republic of China, where they reside in the mountainous terrain of the southwest and south. They also form one of the 54 ethnic groups officially recognized by Vietnam. In the last census in 2000, they numbered 2,637,421 in China, and roughly 470,000 in Vietnam.

History

Early history

The origins of the Yao can be traced back 2,000 years ago, starting in Hunan Province. The Yao and Miao people were among the rebels during the Miao Rebellions against the Ming dynasty. As the Han Chinese expanded in southern China, the Yao retreated into the highlands between Hunan and Guizhou to the north and Guangdong and Guangxi to the south, and stretching into eastern Yunnan. Around 1890 the Guangdong government started taking action against Yao in northwestern Guangdong.

Yao people (East Africa)

The Yao people, Wayao, are a major Bantu ethnic and linguistic group based at the southern end of Lake Malawi, which played an important part in the history of Southeast Africa during the 19th century. The Yao are a predominantly Muslim people of about 2 million spread over three countries, Malawi, northern Mozambique, and in Ruvuma Region and Mtwara Region of Tanzania. The Yao people have a strong cultural identity, which transcends the national borders.

History