Moment (mathematics)

In mathematics, a moment is a specific quantitative measure, used in both mechanics and statistics, of the shape of a set of points. If the points represent mass, then the zeroth moment is the total mass, the first moment divided by the total mass is the center of mass, and the second moment is the rotational inertia. If the points represent probability density, then the zeroth moment is the total probability (i.e. one), the first moment is the mean, the second central moment is the variance, the third moment is the skewness, and the fourth moment (with normalization and shift) is the kurtosis. The mathematical concept is closely related to the concept of moment in physics.

For a bounded distribution of mass or probability, the collection of all the moments (of all orders, from 0 to ∞) uniquely determines the distribution.

Significance of the moments

The n-th moment of a real-valued continuous function f(x) of a real variable about a value c is

It is possible to define moments for random variables in a more general fashion than moments for real values—see moments in metric spaces. The moment of a function, without further explanation, usually refers to the above expression with c = 0.

Moment (film)

Moment (Serbian: Трен, translit. Tren) is a 1978 Yugoslav war film directed by Stole Janković. It was entered into the 11th Moscow International Film Festival where Bata Živojinović won the award for Best Actor.

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Moment (physics)

In physics, moment is a combination of a physical quantity and a distance. Moments are usually defined with respect to a fixed reference point or axis; they deal with physical quantities as measured at some distance from that reference point or axis. For example, a moment of force is the product of a force and its distance from an axis, which causes rotation about that axis. In principle, any physical quantity can be combined with a distance to produce a moment; commonly used quantities include forces, masses, and electric charge distributions.

Elaboration

In its most simple and basic form, a moment is the product of the distance to some point, raised to some power, multiplied by some physical quantity such as the force, charge, etc. at that point:

where is the physical quantity such as a force applied at a point, or a point charge, or a point mass, etc. If the quantity is not concentrated solely at a single point, the moment is the integral of that quantity's density over space:

Ram

Ram, ram, or RAM may refer to:

Used as a word (not as an initialism)

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People and characters

RealAudio

RealAudio is a proprietary audio format developed by RealNetworks and first released in April 1995. It uses a variety of audio codecs, ranging from low-bitrate formats that can be used over dialup modems, to high-fidelity formats for music. It can also be used as a streaming audio format, that is played at the same time as it is downloaded. In the past, many internet radio stations used RealAudio to stream their programming over the internet in real time. In recent years, however, the format has become less common and has given way to more popular audio formats. RealAudio was heavily used by the BBC websites until 2009, though it was discontinued due to its declining use. BBC World Service, the last of the BBC websites to use RealAudio, discontinued its usage in March 2011.

File extensions

RealAudio files were originally identified by a filename extension of .ra (for Real Audio). In 1997, RealNetworks also began offering a video format called RealVideo. The combination of the audio and video formats was called RealMedia and used the file extension .rm. However, the latest version of RealProducer, Real's flagship encoder, reverted to using .ra for audio-only files, and began using .rv for video files (with or without audio), and .rmvb for VBR video files. The .ram (Real Audio Metadata) and .smil (Synchronized Multimedia Integration Language) file formats are sometimes encountered as links from web pages (see Streaming Audio section below).

Goat (zodiac)

The Goat (Chinese: 羊; pinyin: yáng) is the eighth sign of the 12-year cycle of animals that appear in the Chinese zodiac related to the Chinese calendar. The sign is also referred to as the Ram or Sheep sign, since the Chinese word yáng is more accurately translated as Caprinae, a taxonomic subfamily which includes both sheep and goats.

The Year of the Goat (alternatively, Year of the Ram or Year of the Sheep) is associated with the 8th Earthly Branch symbol, 未 (wèi).

Goat or Sheep

The Chinese word yáng refers both to goats and sheep, with shānyáng specifically goats and miányáng sheep. In English, the sign (originally based on a horned animal) may be called either. The interpretation of sheep or goat depends on culture. In Vietnamese, the sign is mùi, which is unambiguously goat. In Japan, on the other hand, the sign is hitsuji, sheep; while in Korea and Mongolia the sign is also sheep or ram. Within China, there may be a regional distinction with the zodiacal yáng more likely to be thought of as a goat in the south, while tending to be thought of as a sheep in the north.