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Metcalf's Law
Metcalfe's law states that the value of a telecommunications network is proportional to the square of the number of connected users of the system (''n''2). First formulated in this form by George Gilder in 1993, and attributed to Robert Metcalfe in regard to Ethernet, Metcalfe's law was originally presented, c. 1980, not in terms of users, but rather of "compatible communicating devices" (e.g., fax machines, telephones). Only later with the globalization of the Internet did this law carry over to users and networks as its original intent was to describe Ethernet connections. Network effects Metcalfe's law characterizes many of the network effects of communication technologies and networks such as the Internet, social networking and the World Wide Web. Former Chairman of the U.S. Federal Communications Commission Reed Hundt said that this law gives the most understanding to the workings of the Internet. Metcalfe's Law is related to the fact that the number of unique possible c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sigmoid Function
A sigmoid function is a mathematical function having a characteristic "S"-shaped curve or sigmoid curve. A common example of a sigmoid function is the logistic function shown in the first figure and defined by the formula: :S(x) = \frac = \frac=1-S(-x). Other standard sigmoid functions are given in the Examples section. In some fields, most notably in the context of artificial neural networks, the term "sigmoid function" is used as an alias for the logistic function. Special cases of the sigmoid function include the Gompertz curve (used in modeling systems that saturate at large values of x) and the ogee curve (used in the spillway of some dams). Sigmoid functions have domain of all real numbers, with return (response) value commonly monotonically increasing but could be decreasing. Sigmoid functions most often show a return value (y axis) in the range 0 to 1. Another commonly used range is from −1 to 1. A wide variety of sigmoid functions including the logistic and hype ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sarnoff's Law
David Sarnoff (February 27, 1891 – December 12, 1971) was an American businessman and pioneer of American radio and television. Throughout most of his career, he led the Radio Corporation of America (RCA) in various capacities from shortly after its founding in 1919 until his retirement in 1970. He ruled over an ever-growing telecommunications and media empire that included both RCA and NBC, and became one of the largest companies in the world. Named a Reserve Brigadier General of the Signal Corps in 1945, Sarnoff thereafter was widely known as "The General." Sarnoff is credited with ''Sarnoff's law'', which states that the value of a broadcast network is proportional to the number of viewers. Early life and career David Sarnoff was born to a Jewish family in Uzlyany, a small town in the Russian Empire, now part of Belarus, the son of Abraham Sarnoff and Leah Privin. Abraham emigrated to the United States and raised funds to bring the family. Sarnoff spent much of his early c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reed's Law
Reed's law is the assertion of David P. Reed that the utility of large networks, particularly social networks, can scale exponentially with the size of the network. The reason for this is that the number of possible sub-groups of network participants is 2''N'' − ''N'' − 1, where ''N'' is the number of participants. This grows much more rapidly than either * the number of participants, ''N'', or * the number of possible pair connections, ''N''(''N'' − 1)/2 (which follows Metcalfe's law). so that even if the utility of groups available to be joined is very small on a per-group basis, eventually the network effect of potential group membership can dominate the overall economics of the system. Derivation Given a set ''A'' of ''N'' people, it has 2''N'' possible subsets. This is not difficult to see, since we can form each possible subset by simply choosing for each element of ''A'' one of two possibilities: whether to include that ele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pareto Principle
The Pareto principle states that for many outcomes, roughly 80% of consequences come from 20% of causes (the "vital few"). Other names for this principle are the 80/20 rule, the law of the vital few, or the principle of factor sparsity. Management consultant Joseph M. Juran developed the concept in the context of quality control and improvement after reading the works of Italian sociologist and economist Vilfredo Pareto, who wrote about the 80/20 connection while teaching at the University of Lausanne. In his first work, ''Cours d'économie politique'', Pareto showed that approximately 80% of the land in the Kingdom of Italy was owned by 20% of the population. The Pareto principle is only tangentially related to the Pareto efficiency. Mathematically, the 80/20 rule is roughly described by a power law distribution (also known as a Pareto distribution) for a particular set of parameters. Many natural phenomena distribute according to power law statistics. It is an adage of busin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Matthew Effect
The Matthew effect of accumulated advantage, Matthew principle, or Matthew effect, is the tendency of individuals to accrue social or economic success in proportion to their initial level of popularity, friends, wealth, etc. It is sometimes summarized by the adage "the rich get richer and the poor get poorer". The term was coined by sociologists Robert K. Merton and Harriet Zuckerman in 1968 and takes its name from the Parable of the Talents in the biblical Gospel of Matthew. The Matthew effect may largely be explained by preferential attachment, whereby wealth or credit is distributed among individuals according to how much they already have. This has the net effect of making it increasingly difficult for low ranked individuals to increase their totals because they have fewer resources to risk over time, and increasingly easy for high rank individuals to preserve a large total because they have a large amount to risk. The study of Matthew effects were initially focused primarily ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Matching (graph Theory)
In the mathematical discipline of graph theory, a matching or independent edge set in an undirected graph is a set of edges without common vertices. Finding a matching in a bipartite graph can be treated as a network flow problem. Definitions Given a graph a matching ''M'' in ''G'' is a set of pairwise non-adjacent edges, none of which are loops; that is, no two edges share common vertices. A vertex is matched (or saturated) if it is an endpoint of one of the edges in the matching. Otherwise the vertex is unmatched (or unsaturated). A maximal matching is a matching ''M'' of a graph ''G'' that is not a subset of any other matching. A matching ''M'' of a graph ''G'' is maximal if every edge in ''G'' has a non-empty intersection with at least one edge in ''M''. The following figure shows examples of maximal matchings (red) in three graphs. : A maximum matching (also known as maximum-cardinality matching) is a matching that contains the largest possible number of edges. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Eponymous Laws
This list of eponymous laws provides links to articles on laws, principles, adages, and other succinct observations or predictions named after a person. In some cases the person named has coined the law – such as Parkinson's law. In others, the work or publications of the individual have led to the law being so named – as is the case with Moore's law. There are also laws ascribed to individuals by others, such as Murphy's law; or given eponymous names despite the absence of the named person. A–B * Acton's dictum: "Power tends to corrupt, and absolute power corrupts absolutely. Great men are almost always bad men .. * Aitken's law describes how vowel length in Scots and Scottish English is conditioned by environment. Named for Professor A. J. Aitken, who formulated it. * Alder's razor: See Newton's flaming laser sword below. * Allen's rule: Endotherms from colder climates usually have shorter limbs (or appendages) than the equivalent animals from warmer clim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beckstrom's Law
In economics, Beckstrom's law is a model or theorem formulated by Rod Beckstrom. It purports to answer "the decades-old question of 'how valuable is a network'", and states in summary that "The value of a network equals the net value added to each user’s transactions conducted through that network, summed over all users." Law According to its creator, this law can be used to value any network be it social networks, computer networks, support groups and even the Internet as a whole. This new model values the network by looking from the edge of the network at all of the transactions conducted and the value added to each. It states that one way to contemplate the value the network adds to each transaction is to imagine the network being shut off and what the additional transactions costs or loss would be. It can thus be compared to the value of a pizza delivery service offered to its customers. If the pizza delivery service shut down, then the social value generated by its deliverie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anti-rival Good
“Anti-rival good” is a neologism suggested by Steven Weber (professor), Steven Weber. According to his definition, it is the opposite of a rival good. The more people share an anti-rival good, the more utility each person receives. Examples include software and other information goods created through the process of commons-based peer production. An anti-rival good meets the test of a public good because it is non-excludable (freely available to all) and non-rival (consumption by one person does not reduce the amount available for others). However, it has the additional quality of being created by private individuals for common benefit without being motivated by pure altruism, because the individual contributor also receives benefits from the contributions of others. Free open-source software Lawrence Lessig described free and open-source software as anti-rivalrous: "It's not just that code is non-rival; it's that code in particular, and (at least some) knowledge in general ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bitcoin
Bitcoin ( abbreviation: BTC; sign: ₿) is a decentralized digital currency that can be transferred on the peer-to-peer bitcoin network. Bitcoin transactions are verified by network nodes through cryptography and recorded in a public distributed ledger called a blockchain. The cryptocurrency was invented in 2008 by an unknown person or group of people using the name Satoshi Nakamoto. The currency began use in 2009, when its implementation was released as open-source software. The word "''bitcoin''" was defined in a white paper published on October 31, 2008. It is a compound of the words ''bit'' and ''coin''. The legality of bitcoin varies by region. Nine countries have fully banned bitcoin use, while a further fifteen have implicitly banned it. A few governments have used bitcoin in some capacity. El Salvador has adopted Bitcoin as legal tender, although use by merchants remains low. Ukraine has accepted cryptocurrency donations to fund the resistance to the 2022 Russ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tencent
Tencent Holdings Ltd. () is a Chinese multinational technology and entertainment conglomerate and holding company headquartered in Shenzhen. It is one of the highest grossing multimedia companies in the world based on revenue. It is also the world’s largest company in the video game industry based on its investments, with Tencent Games being the subdivision of Tencent Interactive Entertainment Group (IEG) focused on publishing of games. Founded in 1998, its subsidiaries globally market various Internet-related services and products, including in entertainment, artificial intelligence, and other technology. Its twin-skyscraper headquarters, Tencent Seafront Towers (also known as Tencent Binhai Mansion) are based in the Nanshan District of Shenzhen. Tencent is the world's largest video game vendor, as well as one of the most financially valuable companies. It is among the largest social media, venture capital, and investment corporations. Its services include social netwo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
