Syntax

Syntax

Ad Hoc Syntax in Legal Information Retrieval

The following is a basic concept of Ad Hoc Syntax in relation to information retrieval. In addition to this, Ad Hoc Syntax may be applied to legal texts, including case law, legislation and scholarly works. Ad hoc (to this) syntax refers to syntax that is developed on the spot for a one-time indexing project, as opposed to an ongoing indexing operation, such as a regularly updated Information Retrieval database or indexing and abstracting service. The most common example of ad hoc syntax is that used in most back-of-the-book indexes. Indexers who create the detailed indexes to individual books rarely use a pre-established system of syntax, but rather put terms together as they see fit for the particular situation. Because such a book index is a one-time operation, there is no need to record practice for the sake of long-term consistency, although good indexers attempt to maintain consistency throughout a single index.

Permuted Syntax in Legal Information Retrieval

The following is a basic concept of Permuted Syntax in relation to information retrieval. In addition to this, Permuted Syntax may be applied to legal texts, including case law, legislation and scholarly works. Permuted syntax was developed to provide direct access to every two-word pair in an original indexing statement (a document title or a statement prepared by an indexer) or a set of index terms, regardless of whether or not these two words appear next to each other in the original statement or set of index terms. Direct access is provided to every keyword (every word not on a stop list), and each access word is linked to every other non-stop-list word that occurs in the same index statement or set of terms. Compare permuted syntax with the common syntaxes of keyword indexing: KWIC, KWOC, and KWAC.

Postcoordinate, Precoordinate Syntax in Legal Information Retrieval

The following is a basic concept of Postcoordinate, Precoordinate Syntax in relation to information retrieval. In addition to this, Postcoordinate, Precoordinate Syntax may be applied to legal texts, including case law, legislation and scholarly works. The terms postcoordinate syntax and precoordinate syntax are used to indicate when terms are put together to represent documentary units, either before (pre) or after (post) a search begins. All index headings that are constructed for displayed indexes, which users may browse during the searching process, must of necessity be created before the search, so they are called precoordinate headings based on precoordinate syntax. Postcoordinate syntax is used almost exclusively for machine matching, where searchers create search statements, putting terms together at the time of the search, then make use of computer algorithms to find matching records or texts.

Precoordinate Syntax in Legal Information Retrieval

The following is a basic concept of Precoordinate Syntax in relation to information retrieval. In addition to this, Precoordinate Syntax may be applied to legal texts, including case law, legislation and scholarly works. See postcoordinate, precoordinate syntax.

Probabilistic Model Syntax in Legal Information Retrieval

The following is a basic concept of Probabilistic Model Syntax in relation to information retrieval. In addition to this, Probabilistic Model Syntax may be applied to legal texts, including case law, legislation and scholarly works. Throughout the history of automatic indexing based on term weighting and relevance prediction, two major theoretical models have emerged: the vector-space model and the probabilistic model. Probabilistic syntax is based on the probabilistic model, in which statistical data for term frequency and distribution is used to predict the probability of relevance.

Rotated Term Syntax in Legal Information Retrieval

The following is a basic concept of Rotated Term Syntax in relation to information retrieval. In addition to this, Rotated Term Syntax may be applied to legal texts, including case law, legislation and scholarly works. This is the simplest of all string syntax patterns. All terms or descriptors assigned to a documentary unit are arranged in alphanumeric order within the string, and then each term is rotated out to the lead position, one at a time, for access purposes.

String Syntax in Legal Information Retrieval

The following is a basic concept of String Syntax in relation to information retrieval. In addition to this, String Syntax may be applied to legal texts, including case law, legislation and scholarly works. String syntax is the modern version of subject heading syntax, inspired by the desire to take advantage of computer technology for the creation of headings. Because instructions for the combination of terms into headings are programmed for the computer, string syntax tends to be much more regular than the idiosyncratic variety exhibited by subject heading syntax. The name string syntax or string indexing comes from the custom of displaying headings as strings of terms — terms strung together in various configurations. The variety of string syntax approaches is mostly related to how terms are arranged in these strings.

Syntax in Legal Information Retrieval

The following is a basic concept of Syntax in relation to information retrieval. In addition to this, Syntax may be applied to legal texts, including case law, legislation and scholarly works. Syntax is a linguistic term meaning (1) orderly or systematic arrangement, or more precisely, (2) the arrangement of words as elements in a sentence to show their relationship; sentence structure (Websters 1966, p. 1480). It comes from the Greek for putting or arranging together. The first meaning is labeled obsolete, but it is closer to the meaning intended here in borrowing syntax from linguistics and applying it to index headings and search statements. Syntax is used in this book to mean rules or patterns for the combination of terms to form meaningful index headings or effective search statements. Index headings consist of terms arranged in a certain order, and they may display a certain structure as well, so the application of the idea of syntax seems appropriate. In modern search statements for electronic Information Retrieval databases, the order or particular arrangement of terms is often immaterial, but by extension, the idea of syntax is used to refer to the rules or patterns for the combination (as opposed to the arrangement) of terms (for example the use of boolean operators OR, AND, or NOT between terms), and also for the application of techniques for indicating term weights, proximity limits, and truncation, and for stemming and similar refinements to influence the results of a search. Here the analogy corresponds to the grammatical use of inflections (word endings or changes in form) to indicate the role of words in a sentence with respect to number (singular or plural), case (subject, object, possessive), gender (male or female) or tense (past, present, future). In short, indexing or searching syntax is used to refer to the rules or patterns for creating index headings or search statements.

Vector Space Model Syntax in Legal Information Retrieval

The following is a basic concept of Vector Space Model Syntax in relation to information retrieval. In addition to this, Vector Space Model Syntax may be applied to legal texts, including case law, legislation and scholarly works. Throughout the history of automatic indexing based on term weighting and relevance prediction, two major theoretical models have emerged: the vector-space model and the probabilistic model. Vector space syntax is based on the former, in which statistical data for term frequency and distribution is used to create vectors (like arrows) in multi-dimensional space, the length of the vector representing the importance of the term. Similar vectors are created for search statements, and the combined vectors for documentary units that most closely match the combined vectors for a search statement indicate the most promising documentary units, which are retrieved in rank order, based on the degree of vector similarity.

Weighted Term Syntax in Legal Information Retrieval

The following is a basic concept of Weighted Term Syntax in relation to information retrieval. In addition to this, Weighted Term Syntax may be applied to legal texts, including case law, legislation and scholarly works. See best match syntax.


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