The OpenTravel Alliance is a not-for-profit trade association founded in 1999.
53-508: OpenTravel was founded in 1999 by a consortium of travel companies - including air, hotel, car rental, and supporting software companies - with a primary focus on the creation of electronic message structures to facilitate communication between the disparate systems in the global travel industry. The OpenTravel Alliance presented their concepts at its first OpenTravel Advisory Forum meeting on May 25, 1999, in Atlanta, Georgia. The driving force behind
106-487: A Hilbert space , which is also treated in quantum field theory . Following the convention of particle physicists, the term elementary particles is applied to those particles that are, according to current understanding, presumed to be indivisible and not composed of other particles. Ordinary matter is made from first- generation quarks ( up , down ) and leptons ( electron , electron neutrino ). Collectively, quarks and leptons are called fermions , because they have
159-498: A quantum spin of half-integers (−1/2, 1/2, 3/2, etc.). This causes the fermions to obey the Pauli exclusion principle , where no two particles may occupy the same quantum state . Quarks have fractional elementary electric charge (−1/3 or 2/3) and leptons have whole-numbered electric charge (0 or 1). Quarks also have color charge , which is labeled arbitrarily with no correlation to actual light color as red, green and blue. Because
212-1055: A " Theory of Everything ", or "TOE". There are also other areas of work in theoretical particle physics ranging from particle cosmology to loop quantum gravity . In principle, all physics (and practical applications developed therefrom) can be derived from the study of fundamental particles. In practice, even if "particle physics" is taken to mean only "high-energy atom smashers", many technologies have been developed during these pioneering investigations that later find wide uses in society. Particle accelerators are used to produce medical isotopes for research and treatment (for example, isotopes used in PET imaging ), or used directly in external beam radiotherapy . The development of superconductors has been pushed forward by their use in particle physics. The World Wide Web and touchscreen technology were initially developed at CERN . Additional applications are found in medicine, national security, industry, computing, science, and workforce development, illustrating
265-723: A community of major web players and publishers to establish a MediaWiki wiki that seeks to document open web standards called the WebPlatform and WebPlatform Docs. In January 2013, Beihang University became the Chinese host. In 2022 the W3C WebFonts Working Group won an Emmy Award from the National Academy of Television Arts and Sciences for standardizing font technology for custom downloadable fonts and typography for web and TV devices. On 1 January 2023, it reformed as
318-452: A fourth generation of fermions does not exist. Bosons are the mediators or carriers of fundamental interactions, such as electromagnetism , the weak interaction , and the strong interaction . Electromagnetism is mediated by the photon , the quanta of light . The weak interaction is mediated by the W and Z bosons . The strong interaction is mediated by the gluon , which can link quarks together to form composite particles. Due to
371-656: A handwritten "flight interruption manifest" for each ticketholder who's looking to rebook elsewhere. The adoption of an industry-standard setup based on XML allowed electronic tickets to be automatically transferred to another airline's system. In May 2017, OpenTravel added messaging to facilitate reserving golf tee times. Called the OpenTravel Golf 2.0 Standard Connection, the addition allowed golf courses to connect directly with distribution partners in hospitality, air, rental cars, tour operators, OTA’s, rail, by enabling faster, more efficient technical connections. In March 2016,
424-599: A new edition or level of the recommendation. Additionally, the W3C publishes various kinds of informative notes which are to be used as references. Unlike the Internet Society and other international standards bodies, the W3C does not have a certification program. The W3C has decided, for now, that it is not suitable to start such a program, owing to the risk of creating more drawbacks for the community than benefits. In January 2023, after 28 years of being jointly administered by
477-456: A public-interest 501(c)(3) non-profit organization . W3C develops technical specifications for HTML5 , CSS , SVG , WOFF , the Semantic Web stack , XML , and other technologies. Sometimes, when a specification becomes too large, it is split into independent modules that can mature at their own pace. Subsequent editions of a module or specification are known as levels and are denoted by
530-576: A set of core principles and components that are chosen by the consortium. It was originally intended that CERN host the European branch of W3C; however, CERN wished to focus on particle physics , not information technology . In April 1995, the French Institute for Research in Computer Science and Automation became the European host of W3C, with Keio University Research Institute at SFC becoming
583-492: A wide range of exotic particles . All particles and their interactions observed to date can be described almost entirely by the Standard Model. Dynamics of particles are also governed by quantum mechanics ; they exhibit wave–particle duality , displaying particle-like behaviour under certain experimental conditions and wave -like behaviour in others. In more technical terms, they are described by quantum state vectors in
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#1733085908935636-462: A working draft (WD) for review by the community. A WD document is the first form of a standard that is publicly available. Commentary by virtually anyone is accepted, though no promises are made with regard to action on any particular element commented upon. At this stage, the standard document may have significant differences from its final form. As such, anyone who implements WD standards should be ready to significantly modify their implementations as
689-425: Is a particle physics theory suggesting that systems with higher energy have a smaller number of dimensions. A third major effort in theoretical particle physics is string theory . String theorists attempt to construct a unified description of quantum mechanics and general relativity by building a theory based on small strings, and branes rather than particles. If the theory is successful, it may be considered
742-403: Is done by external experts in the W3C's various working groups. The Consortium is governed by its membership. The list of members is available to the public. Members include businesses, nonprofit organizations, universities, governmental entities, and individuals. Membership requirements are transparent except for one requirement: An application for membership must be reviewed and approved by
795-508: Is fundamentally composed of elementary particles dates from at least the 6th century BC. In the 19th century, John Dalton , through his work on stoichiometry , concluded that each element of nature was composed of a single, unique type of particle. The word atom , after the Greek word atomos meaning "indivisible", has since then denoted the smallest particle of a chemical element , but physicists later discovered that atoms are not, in fact,
848-591: Is in model building where model builders develop ideas for what physics may lie beyond the Standard Model (at higher energies or smaller distances). This work is often motivated by the hierarchy problem and is constrained by existing experimental data. It may involve work on supersymmetry , alternatives to the Higgs mechanism , extra spatial dimensions (such as the Randall–Sundrum models ), Preon theory, combinations of these, or other ideas. Vanishing-dimensions theory
901-521: Is made only from the first fermion generation. The first generation consists of up and down quarks which form protons and neutrons , and electrons and electron neutrinos . The three fundamental interactions known to be mediated by bosons are electromagnetism , the weak interaction , and the strong interaction . Quarks cannot exist on their own but form hadrons . Hadrons that contain an odd number of quarks are called baryons and those that contain an even number are called mesons . Two baryons,
954-555: Is now endorsed by the W3C, indicating its readiness for deployment to the public, and encouraging more widespread support among implementors and authors. Recommendations can sometimes be implemented incorrectly, partially, or not at all, but many standards define two or more levels of conformance that developers must follow if they wish to label their product as W3C-compliant. A recommendation may be updated or extended by separately-published, non-technical errata or editor drafts until sufficient substantial edits accumulate for producing
1007-555: Is the main international standards organization for the World Wide Web . Founded in 1994 and led by Tim Berners-Lee , the consortium is made up of member organizations that maintain full-time staff working together in the development of standards for the World Wide Web. As of 5 March 2023, W3C had 462 members. W3C also engages in education and outreach, develops software and serves as an open forum for discussion about
1060-566: Is the study of fundamental particles and forces that constitute matter and radiation . The field also studies combinations of elementary particles up to the scale of protons and neutrons , while the study of combination of protons and neutrons is called nuclear physics . The fundamental particles in the universe are classified in the Standard Model as fermions (matter particles) and bosons (force-carrying particles). There are three generations of fermions, although ordinary matter
1113-483: Is the study of these particles in radioactive processes and in particle accelerators such as the Large Hadron Collider . Theoretical particle physics is the study of these particles in the context of cosmology and quantum theory . The two are closely interrelated: the Higgs boson was postulated by theoretical particle physicists and its presence confirmed by practical experiments. The idea that all matter
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#17330859089351166-562: Is the version of a standard that has passed the prior two levels. The users of the standard provide input. At this stage, the document is submitted to the W3C Advisory Council for final approval. While this step is important, it rarely causes any significant changes to a standard as it passes to the next phase. This is the most mature stage of development. At this point, the standard has undergone extensive review and testing, under both theoretical and practical conditions. The standard
1219-600: Is used to extract the parameters of the Standard Model with less uncertainty. This work probes the limits of the Standard Model and therefore expands scientific understanding of nature's building blocks. Those efforts are made challenging by the difficulty of calculating high precision quantities in quantum chromodynamics . Some theorists working in this area use the tools of perturbative quantum field theory and effective field theory , referring to themselves as phenomenologists . Others make use of lattice field theory and call themselves lattice theorists . Another major effort
1272-474: The Electronic Frontier Foundation 's resignation from W3C. As feared by the opponents of EME, as of 2020 , none of the widely used Content Decryption Modules used with EME are available for licensing without a per-browser licensing fee. W3C/ Internet Engineering Task Force standards (over Internet protocol suite ): Particle physics Particle physics or high-energy physics
1325-1002: The MIT Computer Science and Artificial Intelligence Laboratory (located in Stata Center ) in the United States, the (in Sophia Antipolis , France), Keio University (in Japan) and Beihang University (in China), the W3C incorporated as a legal entity, becoming a public-interest not-for-profit organization . The W3C has a staff team of 70–80 worldwide as of 2015 . W3C is run by a management team which allocates resources and designs strategy, led by CEO Jeffrey Jaffe (as of March 2010), former CTO of Novell . It also includes an advisory board that supports strategy and legal matters and helps resolve conflicts. The majority of standardization work
1378-544: The atomic nuclei are baryons – the neutron is composed of two down quarks and one up quark, and the proton is composed of two up quarks and one down quark. A baryon is composed of three quarks, and a meson is composed of two quarks (one normal, one anti). Baryons and mesons are collectively called hadrons . Quarks inside hadrons are governed by the strong interaction, thus are subjected to quantum chromodynamics (color charges). The bounded quarks must have their color charge to be neutral, or "white" for analogy with mixing
1431-417: The proton and the neutron , make up most of the mass of ordinary matter. Mesons are unstable and the longest-lived last for only a few hundredths of a microsecond . They occur after collisions between particles made of quarks, such as fast-moving protons and neutrons in cosmic rays . Mesons are also produced in cyclotrons or other particle accelerators . Particles have corresponding antiparticles with
1484-421: The quantum fields that also govern their interactions. The dominant theory explaining these fundamental particles and fields, along with their dynamics, is called the Standard Model . The reconciliation of gravity to the current particle physics theory is not solved; many theories have addressed this problem, such as loop quantum gravity , string theory and supersymmetry theory . Practical particle physics
1537-454: The 1950s and 1960s, a bewildering variety of particles was found in collisions of particles from beams of increasingly high energy. It was referred to informally as the " particle zoo ". Important discoveries such as the CP violation by James Cronin and Val Fitch brought new questions to matter-antimatter imbalance . After the formulation of the Standard Model during the 1970s, physicists clarified
1590-665: The Asian host in September 1996. Starting in 1997, W3C created regional offices around the world. As of September 2009, it had eighteen World Offices covering Australia, the Benelux countries (Belgium, Netherlands and Luxembourg), Brazil, China, Finland, Germany, Austria, Greece, Hong Kong, Hungary, India, Israel, Italy, South Korea, Morocco, South Africa, Spain, Sweden, and, as of 2016, the United Kingdom and Ireland. In October 2012, W3C convened
1643-704: The OpenTravel Alliance announced the release of OTA 2.0 object model solution, the next generation of open source messaging for consumer direct bookings. OpenTravel’s 2.0 adds the ability to exchange JSON messaging to the existing XML capabilities. Version 1 of the specification was first released for public review in February 2000. OpenTravel's mission is to engineer specifications to ensure traveler and supplier information flow smoothly throughout travel, tourism and hospitality. OpenTravel creates, expands and drives adoption of open specifications, including but not limited to
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1696-450: The W3C started considering adding DRM -specific Encrypted Media Extensions (EME) to HTML5 , which was criticised as being against the openness, interoperability, and vendor neutrality that distinguished websites built using only W3C standards from those requiring proprietary plug-ins like Flash . On 18 September 2017, the W3C published the EME specification as a recommendation, leading to
1749-516: The W3C. Many guidelines and requirements are stated in detail, but there is no final guideline about the process or standards by which membership might be finally approved or denied. The cost of membership is given on a sliding scale, depending on the character of the organization applying and the country in which it is located. Countries are categorized by the World Bank 's most recent grouping by gross national income per capita. In 2012 and 2013,
1802-828: The Web. The World Wide Web Consortium (W3C) was founded in 1994 by Tim Berners-Lee after he left the European Organization for Nuclear Research ( CERN ) in October 1994. It was founded at the Massachusetts Institute of Technology (MIT) Laboratory for Computer Science with support from the European Commission , and the Defense Advanced Research Projects Agency , which had pioneered the ARPANET ,
1855-462: The adoption of an XML standard throughout the travel industry was the hopes of eliminating one of the major impediments blocking a full conversion to electronic tickets. Before the creation of OpenTravel messaging, passengers who with electronic tickets had to wait in line to receive a paper ticket from their initial airline if a flight has been canceled and they want to try to switch to another carrier. In addition, airline employees would need to fill out
1908-571: The aforementioned color confinement, gluons are never observed independently. The Higgs boson gives mass to the W and Z bosons via the Higgs mechanism – the gluon and photon are expected to be massless . All bosons have an integer quantum spin (0 and 1) and can have the same quantum state . Most aforementioned particles have corresponding antiparticles , which compose antimatter . Normal particles have positive lepton or baryon number , and antiparticles have these numbers negative. Most properties of corresponding antiparticles and particles are
1961-584: The constituents of all matter . Finally, the Standard Model also predicted the existence of a type of boson known as the Higgs boson . On 4 July 2012, physicists with the Large Hadron Collider at CERN announced they had found a new particle that behaves similarly to what is expected from the Higgs boson. The Standard Model, as currently formulated, has 61 elementary particles. Those elementary particles can combine to form composite particles, accounting for
2014-478: The first experimental deviations from the Standard Model, since neutrinos do not have mass in the Standard Model. Modern particle physics research is focused on subatomic particles , including atomic constituents, such as electrons , protons , and neutrons (protons and neutrons are composite particles called baryons , made of quarks ), that are produced by radioactive and scattering processes; such particles are photons , neutrinos , and muons , as well as
2067-455: The first integer in the title (e.g. CSS3 = Level 3). Subsequent revisions on each level are denoted by an integer following a decimal point (for example, CSS2.1 = Revision 1). The W3C standard formation process is defined within the W3C process document, outlining four maturity levels through which each new standard or recommendation must progress. After enough content has been gathered from 'editor drafts' and discussion, it may be published as
2120-424: The fundamental particles of nature, but are conglomerates of even smaller particles, such as the electron . The early 20th century explorations of nuclear physics and quantum physics led to proofs of nuclear fission in 1939 by Lise Meitner (based on experiments by Otto Hahn ), and nuclear fusion by Hans Bethe in that same year; both discoveries also led to the development of nuclear weapons . Throughout
2173-538: The gravitational interaction, but it has not been detected or completely reconciled with current theories. Many other hypothetical particles have been proposed to address the limitations of the Standard Model. Notably, supersymmetric particles aim to solve the hierarchy problem , axions address the strong CP problem , and various other particles are proposed to explain the origins of dark matter and dark energy . The world's major particle physics laboratories are: Theoretical particle physics attempts to develop
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2226-424: The hundreds of other species of particles that have been discovered since the 1960s. The Standard Model has been found to agree with almost all the experimental tests conducted to date. However, most particle physicists believe that it is an incomplete description of nature and that a more fundamental theory awaits discovery (See Theory of Everything ). In recent years, measurements of neutrino mass have provided
2279-433: The interactions between the quarks store energy which can convert to other particles when the quarks are far apart enough, quarks cannot be observed independently. This is called color confinement . There are three known generations of quarks (up and down, strange and charm , top and bottom ) and leptons (electron and its neutrino, muon and its neutrino , tau and its neutrino ), with strong indirect evidence that
2332-456: The mid-1970s after experimental confirmation of the existence of quarks . It describes the strong , weak , and electromagnetic fundamental interactions , using mediating gauge bosons . The species of gauge bosons are eight gluons , W , W and Z bosons , and the photon . The Standard Model also contains 24 fundamental fermions (12 particles and their associated anti-particles), which are
2385-497: The models, theoretical framework, and mathematical tools to understand current experiments and make predictions for future experiments (see also theoretical physics ). There are several major interrelated efforts being made in theoretical particle physics today. One important branch attempts to better understand the Standard Model and its tests. Theorists make quantitative predictions of observables at collider and astronomical experiments, which along with experimental measurements
2438-706: The most direct predecessor to the modern Internet . It was located in Technology Square until 2004, when it moved, with the MIT Computer Science and Artificial Intelligence Laboratory, to the Stata Center. The organization tries to foster compatibility and agreement among industry members in the adoption of new standards defined by the W3C. Incompatible versions of HTML are offered by different vendors, causing inconsistency in how web pages are displayed. The consortium tries to get all those vendors to implement
2491-426: The origin of the particle zoo. The large number of particles was explained as combinations of a (relatively) small number of more fundamental particles and framed in the context of quantum field theories . This reclassification marked the beginning of modern particle physics. The current state of the classification of all elementary particles is explained by the Standard Model , which gained widespread acceptance in
2544-483: The photon or gluon, have no antiparticles. Quarks and gluons additionally have color charges, which influences the strong interaction. Quark's color charges are called red, green and blue (though the particle itself have no physical color), and in antiquarks are called antired, antigreen and antiblue. The gluon can have eight color charges , which are the result of quarks' interactions to form composite particles (gauge symmetry SU(3) ). The neutrons and protons in
2597-426: The primary colors . More exotic hadrons can have other types, arrangement or number of quarks ( tetraquark , pentaquark ). An atom is made from protons, neutrons and electrons. By modifying the particles inside a normal atom, exotic atoms can be formed. A simple example would be the hydrogen-4.1 , which has one of its electrons replaced with a muon. The graviton is a hypothetical particle that can mediate
2650-412: The same mass but with opposite electric charges . For example, the antiparticle of the electron is the positron . The electron has a negative electric charge, the positron has a positive charge. These antiparticles can theoretically form a corresponding form of matter called antimatter . Some particles, such as the photon , are their own antiparticle. These elementary particles are excitations of
2703-444: The same, with a few gets reversed; the electron's antiparticle, positron, has an opposite charge. To differentiate between antiparticles and particles, a plus or negative sign is added in superscript . For example, the electron and the positron are denoted e and e . When a particle and an antiparticle interact with each other, they are annihilated and convert to other particles. Some particles, such as
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#17330859089352756-616: The standard matures. A candidate recommendation is a version of a more mature standard than the WD. At this point, the group responsible for the standard is satisfied that the standard meets its goal. The purpose of the CR is to elicit aid from the development community on how implementable the standard is. The standard document may change further, but significant features are mostly decided at this point. The design of those features can still change due to feedback from implementors. A proposed recommendation
2809-468: The use of XML, for the electronic exchange of business information among all sectors of the travel industry. OpenTravel's schema design supports W3C , IATA and ISO standards. Members of the OpenTravel Alliance include airlines, hotel companies, car rental companies, cruise lines, railways, global distribution systems, distribution companies, solutions providers, software developers and consultants. W3C The World Wide Web Consortium ( W3C )
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