What is "collocation"

Collocation \Col`lo*ca"tion\, n. [L. collocatio.]

1. The act of placing; the state of being placed with something else; disposition in place; arrangement.

   The choice and collocation of words.
   --Sir W. Jones.

2. (Linguistics) a combination of related words within a sentence that occurs more frequently than would be predicted in a random arrangement of words; a combination of words that occurs with sufficient frequency to be recongizable as a common combination, especially a pair of words that occur adjacent to each other. Also called stable collocation. Combinations of words having intervening words between them, such as verb and object pairs, may also be collocations.

mid-15c., from Latin collocationem (nominative collocatio), noun of action from past participle stem of collocare (see collocate). Linguistics sense is attested from 1940.

n. 1 (context uncountable English) The grouping or juxtaposition of things, especially words or sounds. 2 (context countable English) Such a specific grouping. 3 (context linguistics translation studies English) A sequence of words or terms that co-occur more often than would be expected by chance (i.e., the statistically significant placement of particular words in a language). 4 (context mathematics English) A method of determining coefficients in an expansion $y(x)\; =\; y\_\{0\}(x)\; +\; sum\_\{l=0\}^\{q\}alpha\_\{l\}\; y\_\{l\}(x)$ so as to nullify the values of an ordinary differential equation $L[y(x)]=0$ at prescribed points. 5 (context computing English) A service allowing multiple customers to locate network, server(,) and storage gear, connect them to a variety of telecommunications and network service providers, with a minimum of cost and complexity.

1. n. a grouping of words in a sentence

2. the act of positioning close together (or side by side); "it is the result of the juxtaposition of contrasting colors" [syn: juxtaposition, apposition]

In corpus linguistics, a collocation is a sequence of words or terms that co-occur more often than would be expected by chance. In phraseology, collocation is a sub-type of phraseme. An example of a phraseological collocation, as propounded by Michael Halliday, is the expression strong tea. While the same meaning could be conveyed by the roughly equivalent *powerful tea, this expression is considered incorrect by English speakers. Conversely, the corresponding expression for computer, powerful computers is preferred over *strong computers. Phraseological collocations should not be confused with idioms, where meaning is derived, whereas collocations are mostly compositional.

There are about six main types of collocations: adjective+noun, noun+noun (such as collective nouns), verb+noun, adverb+adjective, verbs+prepositional phrase ( phrasal verbs), and verb+adverb.

Collocation extraction is a task that extracts collocations automatically from a corpus, using computational linguistics.

Collocation is a procedure used in remote sensing to match measurements from two or more different instruments. This is done for two main reasons: for validation purposes when comparing measurements of the same variable, and to relate measurements of two different variables either for performing retrievals or for prediction. In the second case the data is later fed into some type of statistical inverse method such as a neural network, statistical classification algorithm, kernel estimator or a linear least squares. In principle, most collocation problems can be solved by a nearest neighbor search, but in practice there are many other considerations involved and the best method is highly specific to the particular matching of instruments. Here we deal with some of the most important considerations along with specific examples.

There are at least two main considerations when performing collocations. The first is the sampling pattern of the instrument. Measurements may be dense and regular, such as those from a cross-track scanning satellite instrument. In this case, some form of interpolation may be appropriate. On the other hand, the measurements may be sparse, such as a one-off field campaign designed for some particular validation exercise. The second consideration is the instrument footprint, which can range from something approaching a point measurement such as that of a radiosonde, or it might be several kilometers in diameter such as that of a satellite-mounted, microwave radiometer. In the latter case, it is appropriate to take into account the instrument antenna pattern when making comparisons with another instrument having both a smaller footprint and a denser sampling, that is, several measurements from the one instrument will fit into the footprint of the other.

Just as the instrument has a spatial footprint, it will also have a temporal footprint, often called the integration time. While the integration time is usually less than a second, which for meteorological applications is essentially instantaneous, there are many instances where some form of time averaging can considerably ease the collocation process.

The collocations will need to be screened based on both the time and length scales of the phenomenon of interest. This will further facilitate the collocation process since remote sensing and other measurement data is almost always binned in some way. Certain atmospheric phenomena such as clouds or convection are quite transient so that we need not consider collocations with a time error of more than an hour or so. Sea ice, on the other hand, moves and evolves quite slowly, so that measurements separated by as much as a day or more might still be useful.