Publicité E▼
distance (n.)
1.the property created by the space between two objects or points
2.size of the gap between two places"the distance from New York to Chicago" "he determined the length of the shortest line segment joining the two points"
3.indifference by personal withdrawal"emotional distance"
4.a distant region"I could see it in the distance"
5.the interval between two times"the distance from birth to death" "it all happened in the space of 10 minutes"
6.a remote point in time"if that happens it will be at some distance in the future" "at a distance of ten years he had forgotten many of the details"
distance (v.)
1.go far ahead of"He outdistanced the other runners"
2.keep at a distance"we have to distance ourselves from these events in order to continue living"
Distance (n.)
1.(MeSH)The degree to which individuals are inhibited or facilitated in their ability to gain entry to and to receive care and services from the health care system. Factors influencing this ability include geographic, architectural, transportational, and financial considerations, among others.
Publicité ▼
Merriam Webster
DistanceDis"tance (?), n. [F. distance, L. distantia.]
1. The space between two objects; the length of a line, especially the shortest line joining two points or things that are separate; measure of separation in place.
Every particle attracts every other with a force . . . inversely proportioned to the square of the distance. Sir I. Newton.
2. Remoteness of place; a remote place.
Easily managed from a distance. W. Irving.
'T is distance lends enchantment to the view. T. Campbell.
[He] waits at distance till he hears from Cato. Addison.
3. (Racing) A space marked out in the last part of a race course.
The horse that ran the whole field out of distance. L'Estrange.
☞ In trotting matches under the rules of the American Association, the distance varies with the conditions of the race, being 80 yards in races of mile heats, best two in three, and 150 yards in races of two-mile heats. At that distance from the winning post is placed the distance post. If any horse has not reached this distance post before the first horse in that heat has reached the winning post, such horse is distanced, and disqualified for running again during that race.
4. (Mil.) Relative space, between troops in ranks, measured from front to rear; -- contrasted with interval, which is measured from right to left. “Distance between companies in close column is twelve yards.” Farrow.
5. Space between two antagonists in fencing. Shak.
6. (Painting) The part of a picture which contains the representation of those objects which are the farthest away, esp. in a landscape.
☞ In a picture, the Middle distance is the central portion between the foreground and the distance or the extreme distance. In a perspective drawing, the Point of distance is the point where the visual rays meet.
7. Ideal disjunction; discrepancy; contrariety. Locke.
8. Length or interval of time; period, past or future, between two eras or events.
Ten years' distance between one and the other. Prior.
The writings of Euclid at the distance of two thousand years. Playfair.
9. The remoteness or reserve which respect requires; hence, respect; ceremoniousness.
I hope your modesty
Will know what distance to the crown is due. Dryden.
'T is by respect and distance that authority is upheld. Atterbury.
10. A withholding of intimacy; alienation; coldness; disagreement; variance; restraint; reserve.
Setting them [factions] at distance, or at least distrust amongst themselves. Bacon.
On the part of Heaven,
Now alienated, distance and distaste. Milton.
11. Remoteness in succession or relation; as, the distance between a descendant and his ancestor.
12. (Mus.) The interval between two notes; as, the distance of a fourth or seventh.
Angular distance, the distance made at the eye by lines drawn from the eye to two objects. -- Lunar distance. See under Lunar. -- North polar distance (Astron.), the distance on the heavens of a heavenly body from the north pole. It is the complement of the declination. -- Zenith distance (Astron.), the arc on the heavens from a heavenly body to the zenith of the observer. It is the complement of the altitude. -- To keep one's distance, to stand aloof; to refrain from familiarity.
If a man makes me keep my distance, the comfort is he keeps his at the same time. Swift.
DistanceDis"tance (?), v. t. [imp. & p. p. Distanced (?); p. pr. & vb. n. Distancing (?).]
1. To place at a distance or remotely.
I heard nothing thereof at Oxford, being then miles distanced thence. Fuller.
2. To cause to appear as if at a distance; to make seem remote.
His peculiar art of distancing an object to aggrandize his space. H. Miller.
3. To outstrip by as much as a distance (see Distance, n., 3); to leave far behind; to surpass greatly.
He distanced the most skillful of his contemporaries. Milner.
Publicité ▼
⇨ voir la définition de Wikipedia
Distance (n.) (MeSH)
Accessibility, Health Services (MeSH), Accessibility of Health Services (MeSH), Access to Health Care (MeSH), Availability of Health Services (MeSH), Contraceptive Availability (MeSH), Health Services Accessibility (MeSH), Locale (MeSH), Program Accessibility (MeSH)
distance (n.)
alienation, aloofness, estrangement, extent, interval, length, range, space, span
distance (v.)
Voir aussi
⇨ Distance Education • Distance Learning • Distance Perception • Education, Distance • Euclidean distance • Ocular Distance Accommodation • Social Distance • angular distance • at a distance • at a great distance • at a short distance • at some distance • complete a distance • cover a distance • delay ground distance • distance learning • distance measurement • distance o.s. • distance oneself • distance selling • distance vision • focal distance • genetic distance • hyperfocal distance • infinite distance • keep one's distance • long distance • long-distance • long-distance call • long-distance runner • long-distance running • mean distance • middle distance • middle-distance • middle-distance runner • safe distance • short-distance runner • skip distance • standoff distance • within striking distance of
Distance (n.) [MeSH]
distance (n.)
distance[ClasseHyper.]
trajet (fr)[DomainDescrip.]
spacing, spatial arrangement[Hyper.]
distant, far - distant, remote - close, near, nigh - distant - close[Dérivé]
distance (n.)
prudence; steadiness; cautiousness; caginess; caution; precaution; care; forethought[Classe]
humility[Classe]
moderateness; moderation[Classe]
restraint; reserve; reservedness; reticence; reservation; check; control; keeping back; purity; modesty; chastity; virtue[ClasseHyper.]
timidity; bashfulness; shyness; timidness; timorousness[Classe]
distance (n.)
part, region[Hyper.]
distant, far[CeQuiEst~]
distance (n.)
interval, time interval[Hyper.]
space - distant, remote, removed[Dérivé]
distance (n.)
point, point in time[Hyper.]
distant, remote, removed - distant[Dérivé]
distance (v.)
hold, keep, keep up, maintain[Hyper.]
aloofness, distance[Dérivé]
Wikipedia
This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (March 2008) |
Distance is a numerical description of how far apart objects are. In physics or everyday discussion, distance may refer to a physical length, or an estimation based on other criteria (e.g. "two counties over"). In mathematics, a distance function or metric is a generalization of the concept of physical distance. A metric is a function that behaves according to a specific set of rules, and provides a concrete way of describing what it means for elements of some space to be "close to" or "far away from" each other.
In most cases, "distance from A to B" is interchangeable with "distance between B and A".
Contents |
In neutral geometry, the distance between (x1.) and (x2) is the length of the line segment between them:
In analytic geometry, the distance between two points of the xy-plane can be found using the distance formula. The distance between (x1, y1) and (x2, y2) is given by:
Similarly, given points (x1, y1, z1) and (x2, y2, z2) in three-space, the distance between them is:
These formulae are easily derived by constructing a right triangle with a leg on the hypotenuse of another (with the other leg orthogonal to the plane that contains the 1st triangle) and applying the Pythagorean theorem.
In the study of complicated geometries, we call this (most common) type of distance Euclidean distance, as it is derived from the Pythagorean theorem, which does not hold in Non-Euclidean geometries. This distance formula can also be expanded into the arc-length formula.
In the Euclidean space Rn, the distance between two points is usually given by the Euclidean distance (2-norm distance). Other distances, based on other norms, are sometimes used instead.
For a point (x1, x2, ...,xn) and a point (y1, y2, ...,yn), the Minkowski distance of order p (p-norm distance) is defined as:
1-norm distance | |
2-norm distance | |
p-norm distance | |
infinity norm distance | |
p need not be an integer, but it cannot be less than 1, because otherwise the triangle inequality does not hold.
The 2-norm distance is the Euclidean distance, a generalization of the Pythagorean theorem to more than two coordinates. It is what would be obtained if the distance between two points were measured with a ruler: the "intuitive" idea of distance.
The 1-norm distance is more colourfully called the taxicab norm or Manhattan distance, because it is the distance a car would drive in a city laid out in square blocks (if there are no one-way streets).
The infinity norm distance is also called Chebyshev distance. In 2D, it is the minimum number of moves kings require to travel between two squares on a chessboard.
The p-norm is rarely used for values of p other than 1, 2, and infinity, but see super ellipse.
In physical space the Euclidean distance is in a way the most natural one, because in this case the length of a rigid body does not change with rotation.
The Euclidean distance between two points in space ( and ) may be written in a variational form where the distance is the minimum value of an integral:
Here is the trajectory (path) between the two points. The value of the integral (D) represents the length of this trajectory. The distance is the minimal value of this integral and is obtained when where is the optimal trajectory. In the familiar Euclidean case (the above integral) this optimal trajectory is simply a straight line. It is well known that the shortest path between two points is a straight line. Straight lines can formally be obtained by solving the Euler-Lagrange equations for the above functional. In non-Euclidean manifolds (curved spaces) where the nature of the space is represented by a metric the integrand has be to modified to , where Einstein summation convention has been used.
The Euclidean distance between two objects may also be generalized to the case where the objects are no longer points but are higher-dimensional manifolds, such as space curves, so in addition to talking about distance between two points one can discuss concepts of distance between two strings. Since the new objects that are dealt with are extended objects (not points anymore) additional concepts such as non-extensibility, curvature constraints, and non-local interactions that enforce non-crossing become central to the notion of distance. The distance between the two manifolds is the scalar quantity that results from minimizing the generalized distance functional, which represents a transformation between the two manifolds:
The above double integral is the generalized distance functional between two plymer conformation. is a spatial parameter and is pseudo-time. This means that is the polymer/string conformation at time and is parameterized along the string length by . Similarly is the trajectory of an infinitesimal segment of the string during transformation of the entire string from conformation to conformation . The term with cofactor is a Lagrange multiplier and its role is to ensure that the length of the polymer remains the same during the transformation. If two discrete polymers are inextensible, then the minimal-distance transformation between them no longer involves purely straight-line motion, even on a Euclidean metric. There is a potential application of such generalized distance to the problem of protein folding[1][2] This generalized distance is analogous to the Nambu-Goto action in string theory, however there is no exact correspondence because the Euclidean distance in 3-space is inequivalent to the space-time distance minimized for the classical relativistic string.
This section requires expansion. |
The algebraic distance is a metric often used in computer vision that can be minimized by least squares estimation. [1][2] For curves or surfaces given by the equation (such as a conic in homogeneous coordinates), the algebraic distance from the point to the curve is simply . It may serve as an "initial guess" for geometric distance to refine estimations of the curve by more accurate methods, such as non-linear least squares.
In mathematics, in particular geometry, a distance function on a given set M is a function d: M×M → R, where R denotes the set of real numbers, that satisfies the following conditions:
Such a distance function is known as a metric. Together with the set, it makes up a metric space.
For example, the usual definition of distance between two real numbers x and y is: d(x,y) = |x − y|. This definition satisfies the three conditions above, and corresponds to the standard topology of the real line. But distance on a given set is a definitional choice. Another possible choice is to define: d(x,y) = 0 if x = y, and 1 otherwise. This also defines a metric, but gives a completely different topology, the "discrete topology"; with this definition numbers cannot be arbitrarily close.
Various distance definitions are possible between objects. For example, between celestial bodies one should not confuse the surface-to-surface distance and the center-to-center distance. If the former is much less than the latter, as for a LEO, the first tends to be quoted (altitude), otherwise, e.g. for the Earth-Moon distance, the latter.
There are two common definitions for the distance between two non-empty subsets of a given set:
The distance between a point and a set is the infimum of the distances between the point and those in the set. This corresponds to the distance, according to the first-mentioned definition above of the distance between sets, from the set containing only this point to the other set.
In terms of this, the definition of the Hausdorff distance can be simplified: it is the larger of two values, one being the supremum, for a point ranging over one set, of the distance between the point and the set, and the other value being likewise defined but with the roles of the two sets swapped.
In graph theory the distance between two vertices is the length of the shortest path between those vertices.
Distance cannot be negative and distance travelled never decreases. Distance is a scalar quantity or a magnitude, whereas displacement is a vector quantity with both magnitude and direction.
The distance covered by a vehicle (for example as recorded by an odometer), person, animal, or object along a curved path from a point A to a point B should be distinguished from the straight line distance from A to B. For example whatever the distance covered during a round trip from A to B and back to A, the displacement is zero as start and end points coincide. In general the straight line distance does not equal distance travelled, except for journeys in a straight line.
Directed distances are distances with a direction or sense. They can be determined along straight lines and along curved lines. A directed distance along a straight line from A to B is a vector joining any two points in a n-dimensional Euclidean vector space. A directed distance along a curved line is not a vector and is represented by a segment of that curved line defined by endpoints A and B, with some specific information indicating the sense (or direction) of an ideal or real motion from one endpoint of the segment to the other (see figure). For instance, just labelling the two endpoints as A and B can indicate the sense, if the ordered sequence (A, B) is assumed, which implies that A is the starting point.
A displacement (see above) is a special kind of directed distance defined in mechanics. A directed distance is called displacement when it is the distance along a straight line (minimum distance) from A and B, and when A and B are positions occupied by the same particle at two different instants of time. This implies motion of the particle. displace is a vector quantity.
Another kind of directed distance is that between two different particles or point masses at a given time. For instance, the distance from the center of gravity of the Earth A and the center of gravity of the Moon B (which does not strictly imply motion from A to B).Shortest path length may be equal to displacement or may not be equal to.Distance from starting point is always equal to magnitude of displacement. For same particle distance travelled is always greater than or equal to magnitude of displacement. Shortest path length is not necessary always displacement.Diplacement may increase or decrease but distance travelled never decreases.
Circular distance is the distance traveled by a wheel. The circumference of the wheel is 2π × radius, and assuming the radius to be 1, then each revolution of the wheel is equivalent of the distance 2π radians. In engineering ω = 2πƒ is often used, where ƒ is the frequency.
|
|
Contenu de sensagent
dictionnaire et traducteur pour sites web
Alexandria
Une fenêtre (pop-into) d'information (contenu principal de Sensagent) est invoquée un double-clic sur n'importe quel mot de votre page web. LA fenêtre fournit des explications et des traductions contextuelles, c'est-à-dire sans obliger votre visiteur à quitter votre page web !
Essayer ici, télécharger le code;
SensagentBox
Avec la boîte de recherches Sensagent, les visiteurs de votre site peuvent également accéder à une information de référence pertinente parmi plus de 5 millions de pages web indexées sur Sensagent.com. Vous pouvez Choisir la taille qui convient le mieux à votre site et adapter la charte graphique.
Solution commerce électronique
Augmenter le contenu de votre site
Ajouter de nouveaux contenus Add à votre site depuis Sensagent par XML.
Parcourir les produits et les annonces
Obtenir des informations en XML pour filtrer le meilleur contenu.
Indexer des images et définir des méta-données
Fixer la signification de chaque méta-donnée (multilingue).
Renseignements suite à un email de description de votre projet.
Jeux de lettres
Les jeux de lettre français sont :
○ Anagrammes
○ jokers, mots-croisés
○ Lettris
○ Boggle.
Lettris
Lettris est un jeu de lettres gravitationnelles proche de Tetris. Chaque lettre qui apparaît descend ; il faut placer les lettres de telle manière que des mots se forment (gauche, droit, haut et bas) et que de la place soit libérée.
boggle
Il s'agit en 3 minutes de trouver le plus grand nombre de mots possibles de trois lettres et plus dans une grille de 16 lettres. Il est aussi possible de jouer avec la grille de 25 cases. Les lettres doivent être adjacentes et les mots les plus longs sont les meilleurs. Participer au concours et enregistrer votre nom dans la liste de meilleurs joueurs ! Jouer
Dictionnaire de la langue française
Principales Références
La plupart des définitions du français sont proposées par SenseGates et comportent un approfondissement avec Littré et plusieurs auteurs techniques spécialisés.
Le dictionnaire des synonymes est surtout dérivé du dictionnaire intégral (TID).
L'encyclopédie française bénéficie de la licence Wikipedia (GNU).
Copyright
Les jeux de lettres anagramme, mot-croisé, joker, Lettris et Boggle sont proposés par Memodata.
Le service web Alexandria est motorisé par Memodata pour faciliter les recherches sur Ebay.
La SensagentBox est offerte par sensAgent.
Traduction
Changer la langue cible pour obtenir des traductions.
Astuce: parcourir les champs sémantiques du dictionnaire analogique en plusieurs langues pour mieux apprendre avec sensagent.
calculé en 0,047s