به نام خداوند موسیقی و عشق - دانستنیهای علمی

Parkour

امیر علی — Mon, 4 Jul 2011 19:47:01 GMT

From Wikipedia, the free encyclopedia

It has been suggested that this article or section be merged with Free running. (Discuss) Proposed since June 2011.

**Parkour**
Characteristics
Passement
Nickname(s)	PK
Contact	Non-competitive
Categorization	Spiritual art, Body art, Philosophical
Olympic	No

Parkour (sometimes abbreviated PK) is the non-competitive sport originating in France of traversing mainly urban landscapes by running, climbing and jumping. Participants run along a route, attempting to navigate obstacles in the most efficient way possible, using only their bodies. Skills such as vaulting, rolling, swinging and wall scaling are employed. Parkour can be practiced anywhere, but areas dense with obstacles are preferable and it is most commonly practiced in urban areas.

A practitioner of parkour is called a "traceur", which is most likely derived from Parisian slang "tracer" which means "to hurry" or "to move quickly". In proper French, traceur is an adjective qualifying something that leaves a trace or a trail behind it.

In practice, a traceur may use several different names interchangeably for parkour, including "freerunning" or "l'art du déplacement", even though these terms refer to distinct parts of the discipline. While parkour and l'art du déplacement aim to enable the practitioner to move quickly and creatively past obstacles, freerunning includes the use of tricking moves such as aerial rotations and spins. (see below).

Overview

A basic parkour move

Two primary characteristics of parkour are efficiency and speed. Traceurs take the most direct path through an obstacle as rapidly as that route can be traversed safely. Developing one's level of spatial awareness is often used to aid development in these areas. Also, efficiency involves avoiding injuries, both short and long term. This idea embodying parkour's unofficial motto is être et durer ("to be and to last").

Parkour's emphasis on efficiency distinguishes it from the similar practice of free running, which places more emphasis on freedom of movement and creativity.

Traceurs say that parkour also influences one's thought processes by enhancing self-confidence and critical-thinking skills that allow one to overcome everyday physical and mental obstacles.^[1]^[2]^[3] A study by Neuropsychiatrie de l'Enfance et de l'Adolescence (Neuropsychiatry of Childhood and Adolescence) in France reflects that traceurs seek more excitement and leadership situations than do gymnastic practitioners.^[4]

Terminology

The first terms used to describe this form of training were "l'art du déplacement" and "le parcours".^[5] The term "parkour" (French pronunciation: [paʁˈkuʁ]) was coined by Hubert Koundé. It derives from "parcours du combattant", the classic obstacle course method of military training proposed by Georges Hébert.^[6]^[7]^[8] "Traceur" [tʁasœʁ] and "traceuse" [tʁasøz] are substantives derived from the French verb "tracer", which normally means "trace",^[9] or "trail", (i.e. he escaped without a trace) but which is also a slang for "to go fast".^[10]

History

Historical precedents

In the film Jump London, Sebastien Foucan states that "Le Parkour has always existed, free running has always been there, the thing is that no one gave it a name, we didn’t put it in the box. It is an ancient art [...] The Neanderthals, to hunt, or to chase, or to move around, they had to practice the free run." Tangible historical precedents may be traced to movie stuntmen and martial arts practitioners. Hollywood stars and stuntmen such as Douglas Fairbanks, Sr., John Ciampa and Buster Keaton captured parkour-like moves on film as early as the 1920–40s. The latter was also an inspiration for the famous on-foot chase scenes of Hong Kong stuntman, martial artist and actor Jackie Chan.^[11] In Eastern martial arts such as Ninjutsu and Qing Gong, movements similar to those of Parkour have been taught for centuries and with a similar aim. In Jump London, Foucan does acknowledge the influence of martial arts movies on the development of Parkour: "We also climbed onto the roof of our school. We pretended we were Ninja warriors".

A "traceur" performing a "passe muraille"

Hébert's legacy

Main article: Georges Hébert

Before World War I, former naval officer Georges Hébert travelled throughout the world. During a visit to Africa, he was impressed by the physical development and skills of indigenous tribes that he met:^[12] He noted, "their bodies were splendid, flexible, nimble, skillful, enduring, and resistant but yet they had no other tutor in gymnastics but their lives in nature." ^[12]

On May 8, 1902, Saint-Pierre, Martinique, where Hébert was stationed, suffered from a volcanic eruption of Mount Pelée. Hébert coordinated the escape and rescue of some 700 people. This experience had a profound effect on him, and reinforced his belief that athletic skill must be combined with courage and altruism. He eventually developed this ethos into his motto "être fort pour être utile" (" be strong to be useful").^[12] Inspired by indigenous tribes, Hébert became a physical education tutor at the college of Reims in France. He began to define the principles of his own system of physical education and to create various apparatuses and exercises to teach his "méthode naturelle"^[12] which he defined as: "Methodical, progressive and continuous action, from childhood to adulthood, that has as its objective: assuring integrated physical development; increasing organic resistances; emphasizing aptitudes across all genres of natural exercise and indispensable utilities (walking, running, jumping, quadrupedal movement, climbing, equilibrium (balancing), throwing, lifting, defending and swimming); developing one's energy and all other facets of action or virility such that all assets, both physical and virile, are mastered; one dominant moral idea: altruism."^[13]

Hébert set up a "méthode naturelle" session consisting of ten fundamental groups: walking, running, jumping, quadrupedal movement, climbing, balancing, throwing, lifting, self-defense, swimming, which are part of three main forces:^[13]

Energetic or virile sense: energy, willpower, courage, coolness, and firmness
Moral sense: benevolence, assistance, honor, and honesty
Physical sense: muscles and breath

During World War I and World War II, Hébert's teaching continued to expand, becoming the standard system of French military education and training. Thus, Hébert was one of the proponents of "parcours", an obstacle course, developed by a Swiss architect,^[14] which is standard in the military training and led to the development of civilian fitness trails and confidence courses.^[12] Also, French soldiers and firefighters developed their obstacle courses known as "parcours du combattant" and parcours SP".^[15]

Belle family

David Belle, parkour founder, at The New Yorker Festival

Main articles: Raymond Belle and David Belle

Raymond Belle was born in Vietnam, at the time part of French Indochina. His father died during the First Indochina War and Raymond was separated from his mother during the division of Vietnam in 1954. He was taken by the French Army in Da Lat and received a military education and training that shaped his character.^[16] After the Battle of Dien Bien Phu, Raymond was repatriated to France and completed his military education in 1958. At age 19, his dedication to fitness helped him serve in Paris's regiment of "sapeurs-pompiers" (the French fire service).^[16]

David participated in activities such as martial arts and gymnastics and sought to apply his athletic prowess for some practical purpose. He trained extremely hard mostly to try to win the approval of his father (Raymond).^[15] At age 17, David left school seeking freedom and action. He continued to develop his strength and dexterity in order to be useful in life, as Raymond had advised him.^[15]

Development in Lisses

After moving to Lisses commune, David Belle continued his journey with others who would later form the group the Yamakasi.^[15] Sébastien Foucan noted in Jump London "From then on we developed and really the whole town was there for us; there for parkour. You just have to look, you just have to think, like children." This, as he describes, is "the vision of parkour."

In 1997, Yann Hnautra, Charles Perriere, Chau Belle, David Belle, Laurent Piemontesi, Sébastien Foucan, Guylain Perriere, Malik Diouf and Williams Belle created the group Yamakasi,^[17] whose name comes from the Lingala language of Congo, and means "strong spirit, strong body, strong man, endurance". After the musical show Notre Dame de Paris, Belle and Foucan split up due to money and disagreements over the definition of "l'art du déplacement",^[18] The film Yamakasi (2001), and the French documentary Génération Yamakasi were created without Belle and Foucan.

Over the years, as dedicated practitioners improved their skills, their numbers of moves grew. Building-to-building jumps and drops of over a storey became common in media portrayals, often leaving people with a slanted view of parkour. Ground-based movements are more common, because legal accessibility in urban areas is difficult. From the Parisian suburbs, parkour went on to become a widely practiced activity outside of France.^{[citation needed]}

Philosophy and theories

According to Williams Belle, the philosophies and theories behind parkour are an integral aspect of the art, one that many non-practitioners have never been exposed to. Belle trains people because he wants "it to be alive" and for "people to use it".^[3] Châu Belle explains it is a "type of freedom" or "kind of expression"; that parkour is "only a state of mind" rather than a set of actions, and that it is about overcoming and adapting to mental and emotional obstacles as well as physical barriers.^[3]

A newer convention of parkour philosophy has been the idea of "human reclamation".^[19] Andy (Animus of Parkour North America) clarifies it as "a means of reclaiming what it means to be a human being. It teaches us to move using the natural methods that we should have learned from infancy. It teaches us to touch the world and interact with it, instead of being sheltered by it."^[19]"It is as much as a part of truly learning the physical art as well as being able to master the movements, it gives you the ability to overcome your fears and pains and reapply this to life as you must be able to control your mind in order to master the art of parkour."^[20]

A point has been made about the similarities between the martial arts philosophy of Bruce Lee and Parkour.^[21] In an interview with The New Yorker, David Belle acknowledges the influence of Lee's thinking: "There’s a quote by Bruce Lee that’s my motto: ‘There are no limits. There are plateaus, but you must not stay there, you must go beyond them. A man must constantly exceed his level.’ If you’re not better than you were the day before, then what are you doing—what’s the point?".^[22]

Non-rivalry

A campaign was started on 1 May 2007 by Parkour.NET portal^[23] to preserve parkour's philosophy against sport competition and rivalry.^[24] In the words of Erwan LeCorre: "Competition pushes people to fight against others for the satisfaction of a crowd and/or the benefits of a few business people by changing its mindset. Parkour is unique and cannot be a competitive sport unless it ignores its altruistic core of self development. If parkour becomes a sport, it will be hard to seriously teach and spread parkour as a non-competitive activity. And a new sport will be spread that may be called parkour, but that won't hold its philosophical essence anymore."^[23] According to LeCorre, those who truly practice Parkour have the same mind aspect of each other, therefore it brings people to work together rather than compete, it allows them to be united internationally and forget the social and economical problems which separated them globally, ultimately leading one giant community working and growing together.

Freerunning

Main article: Free running

A saut de bras

The term "freerunning" was coined during the filming of Jump London, as a way to present parkour to the English-speaking world. Parkour and Free Running have very little differences.

The man who coined the phrase Sébastien Foucan defines freerunning as a discipline for self development, of following your own way^{[citation needed]}. His dissatisfaction with the limited creativity and self-expression in Parkour was the motivation for Sebastian Foucan to develop a similar but also very different art of movement that became known as freerunning.^[25] He notes "Understand that this form of art has been created by few soldiers in Vietnam to escape or reach: and this is the spirit we'd like parkour to keep. You have to make the difference between what is useful and what is not in emergency situations. Then you'll know what is parkour and what is not. So if you do acrobatics things on the street with no other goal than showing off, please don't say it's parkour. Acrobatics existed a long time ago before parkour."^[6]

When questions are raised between the differences of parkour and freerunning, the Yamakasi group deny the differences and say: "parkour, l'art du deplacement, freerunning, the art of movement... they are all the same thing. They are all movement and they all came from the same place, the same nine guys originally. The only thing that differs is each individual's way of moving". ^[26]

Military training

After the attention that parkour received following the film Casino Royale, militaries from different countries began looking for ways to incorporate parkour into training. The British Royal Marines hired parkour athletes to train their members.^[27] Colorado Parkour began a project to introduce parkour into the U.S. military^[28] and parkour is slowly being introduced into the United States Marine Corps.^[29]

Criticism

Parkour is not widely practiced in dedicated public facilities such as skateparks. Although efforts are being made to create places for it, most Tracuers do not like the idea as it is contradictory to the philosophy of freedom. ^[30] Traceurs practice parkour in urban areas such as gyms, parks, playgrounds, offices, and abandoned structures. Concerns have been raised regarding trespassing, damage of property,^[31] and the practice in inappropriate places.^[32] However, most traceurs will take care of their training spots and will remove themselves quickly and quietly from a public place if asked.^[33]^[34] The Magpie Youth Centre free running club in Glen Parva, Leicester has raised 40,000 Euros to build a free running park/training utility on the park opposite the youth center.

Concerns have been raised by law enforcement and fire and rescue teams of the risk in jumping off high buildings.^[35] They argue that practitioners are needlessly risking damage to both themselves and rooftops by practicing at height, with police forces calling for practitioners to stay off the rooftops. ^[36]^[37]^[38] Some figures within the parkour community agree that this sort of behaviour is not to be encouraged.^[37]^[39]^[40]^[41]

American traceur Mark Toorock says that injuries are rare "because participants rely not on what they can't control – wheels or the icy surfaces of snowboarding and skiing – but their own hands and feet," but Lanier Johnson, executive director of the American Sports Medicine Institute, notes that many of the injuries are not reported.^[42] Even when injuries do occur, many members in the parkour community encourage pursuing the most scientifically sound method to recovery and future prevention. ^[43]

Movements

Saut de précision

There are fewer pre-defined movements in parkour than in gymnastics, as there is no list of "moves". Each obstacle a traceur faces presents a unique challenge, committed Tracuers tend to shy away from defining movement. The ability to overcome the challenge depends on multiple factors, for example, on body type, speed, angle of approach, the physical make-up of the obstacle. Parkour is about training the bodymind to react to those obstacles appropriately with a technique that is effective. Often that technique cannot and need not be classified and given a name. In many cases effective parkour techniques depend on fast redistribution of body weight and the use of momentum to perform seemingly difficult or impossible body maneuvers at great speed. Absorption and redistribution of energy is also an important factor, such as body rolls when landing which reduce impact forces on the legs and spine, allowing a traceur to jump from greater heights than those often considered sensible in other forms of acrobatics and gymnastics.

According to David Belle, the practice is to move in such a way that will help you gain the most ground as if escaping or chasing something. Also, if you go from A to B, you need to be able to get back from B to A,^[44] but not necessarily with the same movements or "passements". Despite this, there are many basic versatile and effective techniques that are emphasized for beginners. Most important are good jumping and landing techniques. The roll, used to limit impact after a drop and to carry one's momentum onward, is often stressed as the most important technique to learn.

Basic movements

Some movements defined in parkour are:^[45]

Synonym			Description
French	French pronouncation	English	Description
Atterrissage	[ateʁisaʒ]	Landing	Bending the knees when toes make contact with ground (never land flat footed; always land on toes and ball of your foot, or whole footed).
réception	[ʁesɛpsjɔ̃]
Équilibre	[ekilibʁ]	Balance	Walking along the crest of an obstacle; literally "balance."
Équilibre de chat		Cat Crawl	Quadrupedal movement along the crest of an obstacle.
Franchissement	[fʁɑ̃ʃismɑ̃]Z	Underbar	Jumping or swinging through a gap between obstacles; literally "to cross" or "to break through."
Lâché	[laʃe]	Lache	Hanging drop; lâcher literally meaning "to let go." To hang or swing (on a bar, on a wall, on a branch) and let go, dropping to the ground or to hang from another object. This can refer to almost all hanging/swinging type movements.
Lâché	[laʃe]	swing
Passe muraille	[pas myʁaj]	Pop vault, wall hop, Wallpass, wallrun	Overcoming a tall structure, usually by use of a step off the wall to transform forward momentum into upward momentum, then using the arms to climb onto and over the object.
		Dyno (shortened from "Dynamic^{[clarification needed]}", opposite to "Static")	This movement comes from climbing terminology, and encompasses leaping from a position similar to an armjump, then grabbing an obstacle usually higher than the initial starting place, often used for an overhang. This movement is used when a simpler movement is not possible.
Passement	[pasmɑ̃]	Vault, Pass	To move over an object with one's hand(s) on an object to ease the movement.
Demitour	[dəmi tuʁ]	Turn vault	A vault or dropping movement involving a 180° turn; literally "half turn." This move is often used to place yourself hanging from an object in order to shorten a drop or prepare for a jump.
Demitour	[dəmi tuʁ]	Turn Down
Passement		Speed vault	To overcome an obstacle by jumping side-ways first, then placing one hand on the obstacle to self-right your body and continue running.
		Thief	To overcome an obstacle by using a one-handed vault, then using the other hand at the end of the vault to push oneself forwards in order to finish the move.
		Lazy vault
Saut de chat	[sod ʃa]	Cat pass/jump, (king) kong vault, monkey vault	The saut de chat involves diving forward over an obstacle so that the body becomes horizontal, pushing off with the hands and tucking the legs, such that the body is brought back to a vertical position, ready to land.
Passement assis		Dash vault	This vault involves using the hands to move oneself forwards at the end of the vault. One uses both hands to overcome an obstacle by jumping feet first over the obstacle and pushing off with the hands at the end. Visually, this might seem similar to the saut de chat, but reversed. Allegedly David Belle has questioned the effectiveness of this movement.
Saut de chat inversé		Reverse vault	A vault involving a 180° rotation such that the traceur's back faces forward as they pass the obstacle. The purpose of the rotation is ease of technique in the case of otherwise awkward body position or loss of momentum prior to the vault.
		Kash vault	This vault is a combination of two vaults; the kong vault and the dash vault. After pushing off with the hands in a kong vault, the body continues past vertical over the object until the feet are leading the body. The kash vault is then finished by pushing off the object at the end, as in a dash vault.
Planche	[plɑ̃ʃ]	Muscle-up	To get from a hanging position (wall, rail, branch, arm jump, etc.) into a position where your upper body is above the obstacle, supported by the arms. This then allows for you to climb up onto the obstacle and continue.
Planche	[plɑ̃ʃ]	climb-up
Roulade	[ʁulad]	Roll	A forward roll where the hands, arms and diagonal of the back contact the ground, often called breakfall. Used primarily to transfer the momentum/energy from jumps and to minimize impact, preventing a painful landing. It is similar to the basic kaiten or ukemi and it was taken from martial arts such as judo, ninjutsu, jujutsu, hapkido and aikido.
Saut de bras	[sodbra]	Arm jump	To land on the side of an obstacle in a hanging/crouched position, the hands gripping the top edge, holding the body, ready to perform a muscle up.
		cat leap
		cat grab
Saut de fond	[sodfɔ̃]	Drop	Literally 'jump to the ground' / 'jump to the floor'. To jump down, or drop down from something.
Saut de détente	[sodə detɑ̃t]	Gap jump, running jump	To jump from one place/object to another, over a gap/distance. This technique is most often followed with a roll.
Saut de précision	[so d presiziɔ̃]	Precision	Static or moving jump from one object to a precise spot on another object. This term can refer to any form of jumping however. Often abbreviated to "pre"
précision	[presiziɔ̃]	Precision
Saut de mur		Wall Jump	To step off a wall in order to overcome another obstacle or gain height to grab something
Saut de mur		Tic-Tac
Saut de rotation		Rotary jump	Similar to a kong vault, the person dives and then rotates their lower body around the obstacle. Used for shorter to medium obstacles. For people that have trouble with kong vaults.
Saut de rotation		Rotary vault

Accessories

There is no equipment required, although practitioners normally train wearing light casual clothing:^[46]^[47]

Light upper body garment—such as T-shirt, sleeveless shirt or crop top if anything is worn on the upper body.
Light lower body garment—usually sweatpants, some wear tracksuit bottoms or light shorts.

Comfortable running shoes, that are generally light, with good grip, and flexibility are encouraged. Many traceurs think cheaper and easier to replace shoes are much more practical.^{[citation needed]} More experienced traceurs with stronger feet tend to train barefoot, which is the best way to feel the environment. Various sport shoes manufacturers around the world started offering parkour-specific products. Some traceurs use sweat-bands for forearm protection.^{[citation needed]} Some use thin athletic gloves to protect the hands;^[48] those who do not, preferring to "feel their environment" directly, develop thick callouses.^[49]^[50]

Since parkour is closely related to "méthode naturelle", practitioners sometimes train barefooted to be able to move efficiently without depending on their gear. Some parkour artists also use the lightweight "Feiyue" martial arts shoes. David Belle notes: "bare feet are the best shoes!"^[51]

Popular culture

A traceuse vaults an obstacle.

Main article: Parkour in popular culture

Parkour has been used in television advertisements, news reports and entertainment pieces, often combined with other forms of acrobatics, such as free running, street stunts and tricking.

Film and television

House M.D.: In the episode Brave Heart from Season 6, Donny Compson and other officers are chasing a freerunner in the opening sequence.
The Simpsons: In the episode Sex, Pies and Idiot Scrapes Ned Flanders is trying to catch Homer because they have become bounty hunters and Ned's final mission is to take down Homer.
American Dad features an extended, highly exaggerated parkour scene in the sixth-season episode Stanny Boy and Frantastic, when the middle-aged central characters Stan and Francine are suddenly invited by their much-younger new friends to engage in an impromptu run across the rooftops of urban hi-rise buildings.
Casino Royale has a parkour chase scene near the beginning of the film where James Bond chases a bomb maker (played by freerunner Sébastien Foucan) into and through a construction site.
Paul Blart: Mall Cop The group of people that take over the Mall use skate boarding and Parkour to traverse their newest "heist".
Banlieue 13 & Banlieue 13: Ultimatum features parkour and stars David Belle and Cyril Raffaelli.^[52]
The Australian version of 60 Minutes featured a segment of parkour on September 16, 2007, which featured Sébastien Foucan on a trip to Australia, and French traceur Stephane Vigroux.^[53]
Top Gear Episode 7 (and The Challenges DVD) has James May racing two parkour athletes across Liverpool in a Peugeot 207.^[54]
My Playground, a documentary film by Kaspar Astrup Schröder, explores the way parkour and freerunning is changing the perception of urban space and how the spaces and buildings they are moving on are changing them^[55]
Jump Britain and Jump London are freerunning/parkour documentaries.
Jonas Brothers: Living The Dream featured an episode where the brothers took parkour classes.
The US incarnation of The Office includes an episode, "Gossip", in which several characters climb on desks and jump off chairs in an attempt to emulate parkour.
Yamakasi, a 2001 movie which centers around a group of traceurs in a Parisian ghetto.
Used by Dave (Seann William Scott) in Cop Out (2010 film)
WWE superstar John Morrison is known as The Prince of Parkour and he wrestles in a parkour style.
A sequence in an Indian Movie Tezz (Fast) around a canal at the end of the chase which covers half a dozen different locations ^[56]
In the film, The Other Guys, robbers move in Parkour style against The Rock & Samuel L. Jackson.
In the movie Prince of Persia: The Sands of Time, the Prince makes use of parkour extensively.

Video games

Super Mario 64 as well as Super Mario Sunshine utilize freerunning in wall-kicks, muscle-ups, and precisions (long jumps), along with back and side flips.
Assassin's Creed 's protagonist Altaïr and Assassin's Creed II 's and Assassin's Creed: Brotherhood 's protagonist Ezio use parkour (although the action is referred to as "free-run" while in-game).^[57]^[58]^[59]
Tomb Raider Underworld 's protagonist Lara Croft uses parkour to scale walls and old buildings. It is also possible to do tricking movements.
Mirror's Edge is about a gang of outlaws called "runners," who excel and specialize in parkour.
Prototype mentions parkour by name and it plays a vital role in the game.
Tony Hawk's American Wasteland has several techniques the player can do while not on the skateboard: free-running (although it is called parkour in the game), wall-run, wire-grab, and other parkour movements.
Brink emphasized parkour as part of its S.M.A.R.T. (Smooth Movement Across Random Terrain) system.
Infamous's protagonist Cole uses parkour extensively.
Tron Evolution producer, Alex Peters, said in an interview with GameSpot (Pre-E3) that Tron's basic movements and combat were based on parkour and capoeira. Interview from Gamespot
Crackdown 2 Agents use parkour and other agility movements to clear obstacles and buildings.
Free Running, just as the title implies, is a free running game for PSP and PS2.
Left 4 Dead and its sequel feature the Hunter, a zombie modeled after practitioners of Parkour, whose clothes are battened down with duct tape to prevent wind resistance. When controlled by a human in multiplayer mode, it is possible to perform Parkour from one wall to another.
The Saboteur is a video game set it the Nazi occupied France where the protagonist Sean Devlin uses parkour/free-running to climb buildings, slide through wires, etc.
Uncharted is another video game in which the player must climb many different obstacles and, in one chapter of Uncharted 2, jump from one truck to another to avoid being killed.
Prince of Persia also incorporates the use of parkour when playing as the main protagonist, the Prince. The player can control the Prince to jump from rooftops, climb walls, vault over obstacles, and perform other elements of parkour.
Tom Clancy's Splinter Cell series includes Parkour moves like the turn vault, simple vault, Cat leap etc.

Comic books

Nightrunner, aka Bilal Asselah, is the Paris-based member of Batman, Inc., and a practitioner of parkour.^[60]
Saltando al vacio (Jumping into the void), is a Spanish production containing five comic books. The story is set in Barcelona, and tells the story of three teenagers who do Parkour

GPU چیست؟

امیر علی — Mon, 8 Feb 2010 19:42:29 GMT

واحد پردازش گرافیکی (به انگلیسی: Graphics processing unit) یا به اختصار GPU ابزاری اختصاصی برای رندر کردن گرافیکی (به طور طبیعی به نظر رسیدن تصویر) در کامپیوترهای شخصی، ایستگاه‌های کاری، و یا در کنسولهای بازی است. این واحد گاهی اوقات واحد پردازندهٔ بصری یا VPU نیز نامیده می‌شود. ویژگی‌های واحدهای پردازش مرکزی جدید برای پردازش و ارائه دادن کارهای دیداری (گرافیکی)، آن‌ها را بسیار کارآمدتر از واحد‌های پردازندهٔ مرکزی یا CPU در پردازش الگوریتم‌های پیجید کرده است.

یک GPU معمولاً بر روی کارتهای گرافیکی قرارمی گیرد، اگرچه کارتهای گرافیکی غیر حرفه‌ای مستقیما بر روی بُرد مادر (OnBorad) قرار می‌گیرند.

GPU ابزاری است شامل تعدادی عملگر‌ ابتدایی گرافیکی، که باعث می‌شود نسبت به CPU در خلق تصاویر بر صفحه نمایشگر بسیار سریعتر عمل کنند.

رایج ترین عملگر‌ها برای گرافیک دو بعدی کامپیوترها شامل عملگر BitBLT است که معمولاً در سخت افزار‌های مخصوص یک "Biltter" نامیده می‌شود. این عملگر‌ها برای کشیدن مستطیل، مثلث، دایره و قوس بکار می‌روند. پردازنده‌های گرافیکی جدید، پردازش گرافیک سه بعدی را نیز در رایانه‌ها انجام می‌دهند.

شتاب دهنده ی گرافیکی

* یک واحد پردازش گرافیکی، پردازشگری است که به کارت گرافیکی الحاق شده است تا عملیات ممیز شناورو اعمال مشابه با آن را انجام دهد.
* یک شتاب دهنده گرافیکی از اتصال چندین ریزتراشه جاوی عملگرهای ریاضی ویژه ی رندر کردن گرافیکی را مورد استفاده قرار می دهد.

دهه 1970

تراشه هایANTIC و CTIA امکان کنترل سخت افزاری حالات گرافیکی و متنی و سایر تاثیرات را بر روی آتاری 8-بیتی را فراهم می کردند.تراشه ی ANTIC پرداشگری مخصوص برای نگاشت(در جالت برنامه نویسی) متن و داده ی گرافیکی به خروجی تصویری بود. طراح تراشه ANTIC جی مینر، طراحی تراشه ی گرافیکی را برای کمودور آمیگا نیز بر عهده داشت.[۱]

دهه 1980

کمودور آمیگا اولین وسیلهٔ پرفروش رایانه‌ای بود که شامل یک biltter در قسمت سخت افزار گرافیکی خود بود و نیزIBM ۸۵۱۴ یکی از اولین رایانه های شخصی بود که کارتی گرافیکی از نوع ۲-بعدی را شامل می‌شد.

آمیگا در زمان خودش بی نظیر بود چرا که یکی از خصوصیات آن، که امروزه به نام سیستم شتاب دهندهٔ گرافیکی شناخته می‌شود را دارا بود. تقریباً تمام بار تولید توابع گرافیکی بر عهدهٔ سخت افزار بود، به طور مثال کشیدن خط، پرکردن مساحت اشکال. یک پردازندهٔ کمکی گرافیکی نیز همراه با مجموعهٔ دستورات داخلی مخصوص به خود در این محموعه حاضر بود. تا قبل از ارایه (و حتی تا مدتی بعد بر روی اکثر سیستم‌ها)، این CPU بود که بار تمام جنبه‌های گرافیکی را بر دوش داشت.[۲]

دههٔ ۱۹۹۰

در اوایل دهه ی۹۰ با رشد چشمگیر سیستم عامل مایکروسافت ویندوز، علاقهٔ فراوانی به استفاده از سرعت بیشتر و تفکیک پذیری ۲-بعدی بالاتر (bitmapped graphics) که قبلا توسط ایستگاه‌های کاری یونیکس و رایانه‌های مکینتاش شرکت اپل استفاده شده بود، ایجاد گردید. در بازار فروش، تسلط مایکروسافت به معنی تمرکز و تلاش بیشتر برروی فقط یک فاصل گرافیکی قابل برنامه نویسی بود :دستگاه میانجی گرافیکی (Graphics Device Interface).

در سال ۱۹۹۱، S۳ Graphics؛ S۳ ۸۶C۹۱۱ به عنوان اولین شتاب دهنده تک-چیپ ۲-بعدی معرفی شد.

از سال ۲۰۰۰ تا به حال

با ظهور رابط کابری DirectX نسخهٔ ۸ و توابعی مشابه بانام OpenGL، توانایی برنامه نویسی برای سایه‌زنی، به قابلیت‌های GPU اضافه شد. هر پیکسل اکنون می‌توانست توسط برنامه‌های کوچک که شامل اضافه شدن بافت تصویری به عنوان ورودی‌ها، و یک برنامهٔ کوتاه توانایی پردازش هریک از مختصات سه بعدی را پیش از نمایش تصویر دارا بود .ان ویدیا بازار را با ارایهٔ اولین چیپ که توانایی سایه‌زنی به صورت نرم افزاری را دارا بود، در دست گرفت: جی فورس ۳ (GeForce ۳) که با نام NV۲۰ مشهور شد. در اکتبر ۲۰۰۲، شرکت ATI با معرفی Radoen ۹۷۰۰ ،با نام مستعارR۳۰۰، اولین شتابدهندهٔ دایرکت ۳بعدی نسخهٔ ۹ را معرفی کرد.

توابع مربوط به یک محاسبه

GPUهای جدید از بسیاری از ترانزیستورهایشان برای محاسبهٔ مربوط به گرافیک سه بعدی رایانه‌ها استفاده می‌کنند. آن‌ها در ابتدا برای شتاب دادن به حافظهٔ اصلی، نقشه برداری بافت ها، رندرکردن چند ظلعی های با اضلاع زیاد و به طور کلی چندگوشه‌ها استفاده می‌شدند. ولی بعداً برای کارهای سخت‌تر از جمله شتاب دادن به محاسبات هندسی مانند تبدیل رئوس از یک دستگاه مختصات به یک دستگاه مختصات دیگر استفاده شد. اخیراً با گسترش GPU‌ها , آنها سایه زنی‌های قابل برنامه‌ریزی و رئوس و بافت‌هارا اداره می‌کنند همچنین با بسیاری از عملگر‌های پشتیبانی شده توسط CPU‌ها و الحاقی و محاسبهٔ مقادیر واسط بین دو نقطه، با تکنیک reduce aliasing) و Color Space با دقت بسیار بالا انجام می‌دهد.

منبع:سایت www.fanavaran-se.com

دهان شویه جایگزین مسواک نیست

امیر علی — Fri, 14 Aug 2009 01:29:25 GMT

دهان شویه جایگزین مسواک نیست

یک دندان پزشک با بیان این که دهان شویه ها به هیچ عنوان جایگزین مسواک و نخ دندان نمی شوند بر مصرف محلول دهان شویه بعد از مسواک و نخ تاکید کرد.

دکتر مجید رحمانی، در گفتگو با خبرنگار بهداشت و درمان ایسنا، بیان کرد که دهان شویه‌ ها به سه دسته ی خوش ‌بویی – بهداشتی، درمانی و خانگی تقسیم می شوند.

دهان شویه های خوش بویی - بهداشتی

این دهان شویه ها بدون تجویز پزشک نیز قابل مصرف است و ضرری به همراه ندارد. البته دکتر رحمانی افزود: نوع اول دهان شویه ها که برای خوش بو کردن دهان استفاده می شوند، به دلیل رفع بوی بد دهان و ایجاد حس تازگی و شادابی و کاهش موردی تعداد باکتری‌ های دهان، تا حدودی اثرات درمانی نیز دارند.

دهان شویه های درمانی

وی در توضیح دهان شویه های درمانی آنان را به دو دسته دهان شویه های آنتی باکتریال و فلورایددار تقسیم کرد و با تاکید بر این که این نوع دهان شویه ‌های درمانی براساس نوع بیماری فرد و توسط پزشک معالج تجویز می شود، گفت: این نوع دهان شویه پس از جراحی های لثه و یا به صورت دارویی برای پیشگیری مشکلات دهان و لثه در افراد مستعد تجویز می شود.

معاون آموزشی جهاد دانشگاهی واحد علوم پزشکی تهران با تاکید دوباره درمورد استفاده از دهان ‌شویه های درمانی با تجویز پزشک معالج، گفت: این نوع دهان ‌شویه ها اگر بیش از 2 هفته مورد استفاده قرار گیرند رنگدانه های تیره رنگی بر روی سطح دندان پدیدار می شود و دندان تیره می شود، ولی اگر در زمان مناسب و زیر نظر پزشک معالج استفاده شود به دلیل کاهش میکروب ها در دهان، اثرات مطلوب درمانی بر روی بیماری های لثه ایجاد می کند.

وی دهان شویه های حاوی فلوراید را نوع دوم دهان شویه های درمانی دانست و با بیان این که این نوع دهان شویه ها معمولاً در کودکان تجویز می شود گفت: فلوراید ماده معدنی است که با نفوذ به ساختمان دندان موجب استحکام دندان می شود.

دکتر رحمانی با بیان این که پزشکان مصرف منظم دهان شویه حاوی فلوراید را به کودکانی که دندان شیری دارند و یا به تازگی دندان های دائمی درآوردند توصیه می کنند افزود: مصرف دهان شویه های حاوی فلوراید در برنامه های وزارت بهداشت و آموزش پزشکی نیز قرار دارد.

وی ادامه داد: مصرف این نوع دهان شویه ها موجب استحکام فک و دندان کودک می شود.

دکتر رحمانی با تاکید بر این مطلب که دهان شویه های حاوی فلوراید را نباید بیش از 30 تا 45 ثانیه در دهان نگه داشت گفت:

این دهان شویه ها درصورت بلعیده شدن توسط کودک یا افراد می تواند اثرات سمی در بدن فرد داشته باشد.

دهان شویه های خانگی

عضو هیأت علمی جهاد دانشگاهی علوم پزشکی تهران دسته سوم دهان شویه ها را خانگی و دست ساز معرفی کرد گفت: در بسیاری از خانواده ها به جای دهان شویه های شیمیائی موجود در داروخانه ها از محلول آب نمک، جوش شیرین یا رزماری و نعنا استفاده می کنند که اثرات مثبت درمانی آن ثابت شده است.

وی در پایان با اشاره به این مطلب که دهان شویه ها به هیچ وجه جایگزین مسواک و نخ دندان نمی شوند گفت: هریک از این 3 مورد، عملکرد کارکرد خاص خود را دارند و مناسب است که دهان شویه بعد از مسواک و نخ دندان استفاده شود تا به تمام سطوح دهان و دندان برسد.

بخش تغذیه و سلامت تبیان

به نام خداوند موسیقی و عشق - دانستنیهای علمی

Parkour

Contents

Overview

Terminology

History

Historical precedents

Hébert's legacy

Belle family

Development in Lisses

Philosophy and theories

Non-rivalry

Freerunning

Military training

Criticism

Movements

Basic movements

Accessories

Popular culture

Film and television

Video games

Comic books

GPU چیست؟

دهان شویه جایگزین مسواک نیست

دهان شویه جایگزین مسواک نیست

دهان شویه های خوش بویی - بهداشتی

دهان شویه های درمانی

دهان شویه های خانگی