signature


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signature,

in music: see musical notationmusical notation,
symbols used to make a written record of musical sounds.

Two different systems of letters were used to write down the instrumental and the vocal music of ancient Greece. In his five textbooks on music theory Boethius (c.A.D. 470–A.D.
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.

signature

A group of spectal lines usually in an emission spectrum that identifies a chemical – an atom or molecule, possibly ionized and/or in a rare isotopic form – in a star, stellar environment, galaxy, etc.

Signature

 

in mathematics, a number characterizing a quadratic form. Every quadratic form with real coefficients can be reduced by a nonsingular linear transformation of variables with real coefficients to the form

The difference ρ – q between the number of positive and negative terms in this expression is called the signature of the quadratic form. The numbers ρ and q are independent of the means by which the quadratic form is reduced to the form (*).


Signature

 

a number placed at the lower left-hand corner of the first page of each sheet of printed pages and repeated with an asterisk on the third page. The signature is used as a control in arranging the sections of a publication before binding.

signature

[′sig·nə·chər]
(electronics)
The characteristic pattern of a target as displayed by detection and classification equipment.
(graphic arts)
A folded, printed sheet, usually consisting of 16 or 32 pages, that forms a section of a book or a pamphlet; the sheet may have fewer pages, but is always in multiples of four.
(mathematics)
For a quadratic or Hermitian form, the number of positive coefficients minus the number of negative coefficients when the form is reduced by a linear transformation to a sum of squares of absolute values.
For a symmetric or Hermitian matrix, the number of positive entries minus the number of negative entries when the matrix is transformed to diagonal form.
(naval architecture)
The graphic record of the magnetic properties of a vessel automatically traced as the vessel passes over the sensitive element of a recording instrument; more accurately called magnetic signature.
(ordnance)
The identifying characteristics peculiar to each type of target which enable detecting apparatus, such as certain fuses, to sense and differentiate targets.
(quantum mechanics)
A quantum number α that characterizes a system with the symmetry of a prolate or oblate spheroid and satisfies the equation r = exp (-i πα), where r is the eigenvalue of the system under a rotation through 180° about an axis perpendicular to the symmetry axis.

signature

signature
An example of infrared signature of a helicopter.
signature
i. The characteristic pattern of a target displayed by detection and identification equipment. It can be a radar, IR (infrared), acoustic, or Doppler signature. See also radar signature.
ii. As it relates to air-photo interpretation, it is the visual characteristics of objects on an air photograph that allow one to differentiate them. These characteristics include the tone, shape, size, pattern, texture, and shadow. Tone refers to the relative brightness or colors of an object in an image. Generally, tone is a fundamental element for distinguishing between different targets or features. Variations in tone also allow the elements of the shape, texture, and pattern of objects to be distinguished. Shape refers to the general form, structure, or outline of individual objects. Shape can be a very distinctive clue for interpretation. Straight-edge shapes typically represent urban or agricultural targets, whereas natural features, such as forest edges, are generally more irregular in shape. The size of objects in an image is a function of scale. It is important to assess the size of a target relative to other objects in a scene to aid in the interpretation of that target. Pattern refers to the spatial arrangement of the visibly discernible objects. Typically, an orderly repetition of similar tones and texture will produce a distinctive and ultimately recognizable pattern. Orchards with evenly spaced trees and urban streets with regularly spaced houses are good examples of pattern. Texture refers to the arrangement and frequency of tonal variation in a particular area of the image. Rough textures would consist of a mottled tone where gray levels change abruptly in a small area, whereas smooth textures would have very little tonal variation. Shadow is also helpful in interpretation, as it may provide an idea of the profile and relative height of a target(s).

signature

2. US the part of a medical prescription that instructs a patient how frequently and in what amounts he should take a drug or agent

signature

(1)
A set of function symbols with arities.

signature

(messaging)
(Or sig) A few lines of information about the sender of an electronic mail message or news posting. Most Unix mail and news software will automagically append a signature from a file called .signature in the user's home directory to outgoing mail and news.

A signature should give your real name and your e-mail address since, though these appear in the headers of your messages, they may be munged by intervening software. It is currently (1994) hip to include the URL of your home page on the World-Wide Web in your sig.

The composition of one's sig can be quite an art form, including an ASCII logo or one's choice of witty sayings (see sig quote, fool file). However, large sigs are a waste of bandwidth, and it has been observed that the size of one's sig block is usually inversely proportional to one's prestige on the net.

See also doubled sig, sig virus.

signature

(programming)
A concept very similar to abstract base classes except that they have their own hierarchy and can be applied to compiled classes. Signatures provide a means of separating subtyping and inheritance. They are implemented in C++ as patches to GCC 2.5.2 by Gerald Baumgartner <gb@cs.purdue.edu>.

ftp://ftp.cs.purdue.edu/pub/gb/.

signature

(1) See digital signature and e-mail signature.

(2) A pattern used for matching. Also called a "fingerprint" or "definition." For example, antivirus companies maintain a database that contains the virus code (the signature) of each of the known viruses. To detect a virus, the antivirus program looks for these code strings in executable programs. Spyware blockers that look for spyware and adware also use signature patterns.

An intrusion detection system also uses signatures, which are patterns that suggest an attack. For example, excessive logins that failed or the execution of certain programs.

(3) A unique number built into hardware or software for identification.

(4) A group of printed pages used in the construction of a book or booklet. Typically comprising 16 or 32 pages, signatures may also be 8, 12, 24, 48 or 64 pages long. The signature is printed on one large sheet of paper in a certain "imposition" order that, when cut and folded, results in the correct page sequence. The signatures are then bound together to make the final product.
References in periodicals archive ?
Although the DOE standards allowed AIU Online the option of creating the PINs that each applicant would use as their electronic signature, we opted instead to use the Federal Student Aid (FSA) PIN, which applicants are required to obtain in order to apply for federal financial aid.
After writing an e-mail message, I type a coded abbreviation (zz for example) and the signature appears.
Electronic signature technology could well be such a keystone as it addresses the limited acceptance of electronic document and content management systems.
If you have any questions about whether or not a particular transaction would be binding with an electronic signature, contact your legal counsel or reference the Electronic Transactions Act at http://www.
Widespread use of digital signatures by customers in financial transactions appears to be several years away, but now is the time to agree on a single technology for implementing it, according to a research analyst.
Paredes also questioned the wisdom of targeting paid signature gatherers.
has issued a proposal for a digital signature standard, which allows recipients of electronically transmitted information to verify the sender's identity and the data's integrity.
SAN FRANCISCO -- Visa USA today announced an agreement that gives Visa Signature cardholders special access to Pinehurst Resort, one of the top ten U.
It says, basically, that you cannot deny the legality of an electronic signature just because it is an electronic signature," he explains.
The complexity of documenting electronic commerce increases in proportion to the complexity of the signature method used.
Calemine said the Los Angeles LAFCO started charging for signature verification in 1975.
Visa Signature Living," one of Visa USA's most significant campaigns this year, debuts today in targeted print and online media.