88-995: The Semantic Web , sometimes known as Web 3.0 (not to be confused with Web3 ), is an extension of the World Wide Web through standards set by the World Wide Web Consortium (W3C). The goal of the Semantic Web is to make Internet data machine-readable . To enable the encoding of semantics with the data, technologies such as Resource Description Framework (RDF) and Web Ontology Language (OWL) are used. These technologies are used to formally represent metadata . For example, ontology can describe concepts , relationships between entities , and categories of things. These embedded semantics offer significant advantages such as reasoning over data and operating with heterogeneous data sources. These standards promote common data formats and exchange protocols on
176-466: A Semantic Web , which was also sometimes referred to as Web 3.0. While the Semantic Web envisioned a web of linked data, Web3 in the blockchain context refers to a decentralized internet built upon distributed ledger technologies. The term "Web3" was coined by Polkadot founder and Ethereum co-founder Gavin Wood in 2014, referring to a "decentralized online ecosystem based on blockchain." In 2021,
264-682: A Candidate Recommendation in March 2000. In February 2001, the Semantic Web Activity replaced the Metadata Activity. In 2004 (as part of a wider revision of RDF) RDFS became a W3C Recommendation. Though RDFS provides some support for ontology specification, the need for a more expressive ontology language had become clear. As of Monday, the 31st of May, our working group will officially come to an end. We have achieved all that we were chartered to do, and I believe our work
352-576: A certain degree semantic. In particular, such has been used for structuring scientific research i.a. by research topics and scientific fields by the projects OpenAlex , Wikidata and Scholia which are under development and provide APIs , Web-pages, feeds and graphs for various semantic queries . Tim Berners-Lee has described the Semantic Web as a component of Web 3.0. People keep asking what Web 3.0 is. I think maybe when you've got an overlay of scalable vector graphics – everything rippling and folding and looking misty – on Web 2.0 and access to
440-412: A class may be a subclass of many classes, a class cannot be an instance of another class). OWL DL is so named due to its correspondence with description logic , a field of research that has studied the logics that form the formal foundation of OWL. This one can be expressed as S H O I N ( D ) {\displaystyle {\mathcal {SHOIN}}(\mathbf {D} )} , using
528-560: A common framework that allows data to be shared and reused across application, enterprise, and community boundaries. a declarative representation language influenced by ideas from knowledge representation In the late 1990s, the World Wide Web Consortium (W3C) Metadata Activity started work on RDF Schema (RDFS), a language for RDF vocabulary sharing. The RDF became a W3C Recommendation in February 1999, and RDFS
616-428: A corporation, there is a closed group of users and the management is able to enforce company guidelines like the adoption of specific ontologies and use of semantic annotation . Compared to the public Semantic Web there are lesser requirements on scalability and the information circulating within a company can be more trusted in general; privacy is less of an issue outside of handling of customer data. Critics question
704-453: A discrete item, distinct from other items perhaps listed on the page. Semantic HTML refers to the traditional HTML practice of markup following intention, rather than specifying layout details directly. For example, the use of <em> denoting "emphasis" rather than <i> , which specifies italics . Layout details are left up to the browser, in combination with Cascading Style Sheets . But this practice falls short of specifying
792-640: A false narrative about disruption of legacy tech company hegemony." Kevin Werbach , author of The Blockchain and the New Architecture of Trust , has said that "many so-called 'Web 3.0' solutions are not as decentralized as they seem, while others have yet to show they are scalable, secure and accessible enough for the mass market", adding that this "may change, but it's not a given that all these limitations will be overcome". In early 2022, Moxie Marlinspike , creator of Signal , articulated how Web3
880-410: A few of the triples from the documents that result from dereferencing https://schema.org/Person (green edge) and https://www.wikidata.org/entity/Q1731 (blue edges). Additionally to the edges given in the involved documents explicitly, edges can be automatically inferred: the triple from the original RDFa fragment and the triple from the document at https://schema.org/Person (green edge in
968-533: A fraction of the relevant phenomena related to semantics. Web3 Web3 (also known as Web 3.0 ) is an idea for a new iteration of the World Wide Web which incorporates concepts such as decentralization , blockchain technologies , and token-based economics. This is distinct from Tim Berners-Lee 's concept of the Semantic Web . Some technologists and journalists have contrasted it with Web 2.0 , wherein they say data and content are centralized in
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#17327657678871056-594: A limited and defined domain, and where sharing data is a common necessity, such as scientific research or data exchange among businesses. In addition, other technologies with similar goals have emerged, such as microformats . Many files on a typical computer can also be loosely divided into human-readable documents and machine-readable data. Documents like mail messages, reports, and brochures are read by humans. Data, such as calendars, address books, playlists, and spreadsheets are presented using an application program that lets them be viewed, searched, and combined. Currently,
1144-409: A pair of individual identifiers (that the objects identified are distinct or the same). Axioms specify the characteristics of classes and properties. This style is similar to frame languages , and quite dissimilar to well known syntaxes for DLs and Resource Description Framework (RDF). Sean Bechhofer, et al. argue that though this syntax is hard to parse, it is quite concrete. They conclude that
1232-526: A possible solution to concerns about the over-centralization of the web in a few " Big Tech " companies. Some have expressed the notion that Web3 could improve data security , scalability , and privacy beyond what is currently possible with Web 2.0 platforms. Bloomberg states that skeptics say the idea "is a long way from proving its use beyond niche applications, many of them tools aimed at crypto traders". The New York Times reported that several investors are betting $ 27 billion that Web3 "is
1320-509: A semantic Web integrated across a huge space of data, you'll have access to an unbelievable data resource … "Semantic Web" is sometimes used as a synonym for "Web 3.0", though the definition of each term varies. The next generation of the Web is often termed Web 4.0, but its definition is not clear. According to some sources, it is a Web that involves artificial intelligence , the internet of things , pervasive computing , ubiquitous computing and
1408-647: A semantic web page might look like this: Tim Berners-Lee calls the resulting network of Linked Data the Giant Global Graph , in contrast to the HTML-based World Wide Web. Berners-Lee posits that if the past was document sharing, the future is data sharing . His answer to the question of "how" provides three points of instruction. One, a URL should point to the data. Two, anyone accessing the URL should get data back. Three, relationships in
1496-547: A small graph is being described, in RDFa -syntax using a schema.org vocabulary and a Wikidata ID: The example defines the following five triples (shown in Turtle syntax). Each triple represents one edge in the resulting graph: the first element of the triple (the subject ) is the name of the node where the edge starts, the second element (the predicate ) the type of the edge, and the last and third element (the object ) either
1584-399: A small group of companies sometimes referred to as " Big Tech ". The term "Web3" was coined in 2014 by Ethereum co-founder Gavin Wood , and the idea gained interest in 2021 from cryptocurrency enthusiasts, large technology companies, and venture capital firms. The concepts of Web3 were first represented in 2013. Critics have expressed concerns over the centralization of wealth to
1672-530: A small group of investors and individuals, or a loss of privacy due to more expansive data collection. Billionaires like Elon Musk and Jack Dorsey have argued that Web3 only serves as a buzzword or marketing term. Web 1.0 and Web 2.0 refer to eras in the history of the World Wide Web as it evolved through various technologies and formats. Web 1.0 refers roughly to the period from 1989 to 2004, where most sites consisted of static pages , and
1760-400: A subset of first-order logic that is decidable, propositional logic was used, increasing its power by adding logics represented by convention with acronyms: The W3C-endorsed OWL specification includes the definition of three variants of OWL, with different levels of expressiveness. These are OWL Lite, OWL DL and OWL Full (ordered by increasing expressiveness). Each of these sublanguages is
1848-564: A syntactic extension of its simpler predecessor. The following set of relations hold. Their inverses do not. OWL Lite was originally intended to support those users primarily needing a classification hierarchy and simple constraints. For example, while it supports cardinality constraints, it only permits cardinality values of 0 or 1. It was hoped that it would be simpler to provide tool support for OWL Lite than its more expressive relatives, allowing quick migration path for systems using thesauri and other taxonomies . In practice, however, most of
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#17327657678871936-570: A syntax for describing and exchanging ontologies, and formal semantics that gives them meaning. For example, OWL DL corresponds to the S H O I N ( D ) {\displaystyle {\mathcal {SHOIN}}^{\mathcal {(D)}}} description logic, while OWL 2 corresponds to the S R O I Q ( D ) {\displaystyle {\mathcal {SROIQ}}^{\mathcal {(D)}}} logic. Sound, complete, terminating reasoners (i.e. systems which are guaranteed to derive every consequence of
2024-444: Is "a myth, a fairy story. It's what parents tell their kids about at night if they want them to grow up to become economists". In 2021, SpaceX and Tesla CEO Elon Musk expressed skepticism about Web3 in a tweet, saying that Web3 "seems more marketing buzzword than reality right now." In November 2021, James Grimmelmann of Cornell University referred to Web3 as vaporware , calling it "a promised future internet that fixes all
2112-830: Is a form of programming based on the declaration of semantic data and requires an understanding of how reasoning algorithms will interpret the authored structures. According to Marshall and Shipman, the tacit and changing nature of much knowledge adds to the knowledge engineering problem, and limits the Semantic Web's applicability to specific domains. A further issue that they point out are domain- or organization-specific ways to express knowledge, which must be solved through community agreement rather than only technical means. As it turns out, specialized communities and organizations for intra-company projects have tended to adopt semantic web technologies greater than peripheral and less-specialized communities. The practical constraints toward adoption have appeared less challenging where domain and scope
2200-437: Is an Acme Gizmo with a retail price of €199, or that it is a consumer product. Rather, HTML can only say that the span of text "X586172" is something that should be positioned near "Acme Gizmo" and "€199", etc. There is no way to say "this is a catalog" or even to establish that "Acme Gizmo" is a kind of title or that "€199" is a price. There is also no way to express that these pieces of information are bound together in describing
2288-534: Is being quite well appreciated. The World Wide Web Consortium (W3C) created the Web-Ontology Working Group as part of their Semantic Web Activity. It began work on November 1, 2001 with co-chairs James Hendler and Guus Schreiber. The first working drafts of the abstract syntax , reference and synopsis were published in July 2002. OWL became a formal W3C recommendation on February 10, 2004 and
2376-655: Is from the perspective of human behavior and personal preferences. For example, people may include spurious metadata into Web pages in an attempt to mislead Semantic Web engines that naively assume the metadata's veracity. This phenomenon was well known with metatags that fooled the Altavista ranking algorithm into elevating the ranking of certain Web pages: the Google indexing engine specifically looks for such attempts at manipulation. Peter Gärdenfors and Timo Honkela point out that logic-based semantic web technologies cover only
2464-560: Is more limited than that of the general public and the World-Wide Web. Finally, Marshall and Shipman see pragmatic problems in the idea of ( Knowledge Navigator -style) intelligent agents working in the largely manually curated Semantic Web: In situations in which user needs are known and distributed information resources are well described, this approach can be highly effective; in situations that are not foreseen and that bring together an unanticipated array of information resources,
2552-498: Is needed. Every OWL ontology must be identified by a URI (http://www.example.org/tea.owl, say). This example provides a sense of the syntax. To save space below, preambles and prefix definitions have been skipped. OWL classes correspond to description logic (DL) concepts , OWL properties to DL roles , while individuals are called the same way in both the OWL and the DL terminology. In
2640-402: Is normative. OWL2 specifies an XML serialization that closely models the structure of an OWL2 ontology. The Manchester Syntax is a compact, human readable syntax with a style close to frame languages. Variations are available for OWL and OWL2. Not all OWL and OWL2 ontologies can be expressed in this syntax. Consider an ontology for tea based on a Tea class. First, an ontology identifier
2728-449: Is not as decentralized as it appears to be, mainly due to consolidation in the cryptocurrency field, including in blockchain application programming interfaces which are currently mainly controlled by the companies Alchemy and Infura ; cryptocurrency exchanges which are mainly dominated by Binance , Coinbase , MetaMask , and OpenSea ; and the stablecoin market which is currently dominated by Tether . Marlinspike also remarked that
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2816-519: Is not widely used. OWL DL is designed to provide the maximum expressiveness possible while retaining computational completeness (either φ or ¬φ holds), decidability (there is an effective procedure to determine whether φ is derivable or not), and the availability of practical reasoning algorithms. OWL DL includes all OWL language constructs, but they can be used only under certain restrictions (for example, number restrictions may not be placed upon properties which are declared to be transitive; and while
2904-432: Is undecidable, so no reasoning software is able to perform complete reasoning for it. In OWL 2, there are three sublanguages of the language: The OWL family of languages supports a variety of syntaxes. It is useful to distinguish high level syntaxes aimed at specification from exchange syntaxes more suitable for general use. These are close to the ontology structure of languages in the OWL family. High level syntax
2992-489: Is used to specify the OWL ontology structure and semantics. The OWL abstract syntax presents an ontology as a sequence of annotations , axioms and facts . Annotations carry machine and human oriented meta-data. Information about the classes, properties and individuals that compose the ontology is contained in axioms and facts only. Each class, property and individual is either anonymous or identified by an URI reference . Facts state data either about an individual or about
3080-661: The Bennett Institute for Public Policy at the University of Cambridge defined Web3 as "the putative next generation of the web's technical, legal, and payments infrastructure—including blockchain, smart contracts and cryptocurrencies." According to Liu, Zhuotao, et al. (2021), three fundamental architectural enablers of Web3 were identified as a combination of decentralized or federated platforms, secured interoperability , and verifiable computing through distributed ledger technologies. Some visions are based around
3168-562: The Web of Things among other concepts. According to the European Union, Web 4.0 is "the expected fourth generation of the World Wide Web. Using advanced artificial and ambient intelligence, the internet of things, trusted blockchain transactions, virtual worlds and XR capabilities, digital and real objects and environments are fully integrated and communicate with each other, enabling truly intuitive, immersive experiences, seamlessly blending
3256-784: The World Wide Web Consortium 's (W3C) standard for objects called the Resource Description Framework (RDF). OWL and RDF have attracted significant academic, medical and commercial interest. In October 2007, a new W3C working group was started to extend OWL with several new features as proposed in the OWL 1.1 member submission. W3C announced the new version of OWL on 27 October 2009. This new version, called OWL 2, soon found its way into semantic editors such as Protégé and semantic reasoners such as Pellet, RacerPro, FaCT++ and HermiT. The OWL family contains many species, serializations, syntaxes and specifications with similar names. OWL and OWL2 are used to refer to
3344-438: The meaning is machine-readable . While its critics have questioned its feasibility, proponents argue that applications in library and information science , industry, biology and human sciences research have already proven the validity of the original concept. Berners-Lee originally expressed his vision of the Semantic Web in 1999 as follows: I have a dream for the Web [in which computers] become capable of analyzing all
3432-402: The "HasTypeABBlood" class. If it is stated that the individual Harriet is related via "hasMother" to the individual Sue, and that Harriet is a member of the "HasTypeOBlood" class, then it can be inferred that Sue is not a member of "HasTypeABBlood". This is, however, only true if the concepts of "Parent" and "Mother" only mean biological parent or mother and not social parent or mother. To choose
3520-419: The 1970s. A 2006 survey of ontologies available on the web collected 688 OWL ontologies. Of these, 199 were OWL Lite, 149 were OWL DL and 337 OWL Full (by syntax). They found that 19 ontologies had in excess of 2,000 classes, and that 6 had more than 10,000. The same survey collected 587 RDFS vocabularies. An ontology is an explicit specification of a conceptualization. The data described by an ontology in
3608-456: The 2004 and 2009 specifications, respectively. Full species names will be used, including specification version (for example, OWL2 EL). When referring more generally, OWL Family will be used. There is a long history of ontological development in philosophy and computer science. Since the 1990s, a number of research efforts have explored how the idea of knowledge representation (KR) from artificial intelligence (AI) could be made useful on
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3696-596: The Google approach is more robust. Furthermore, the Semantic Web relies on inference chains that are more brittle; a missing element of the chain results in a failure to perform the desired action, while the human can supply missing pieces in a more Google-like approach. [...] cost-benefit tradeoffs can work in favor of specially-created Semantic Web metadata directed at weaving together sensible well-structured domain-specific information resources; close attention to user/customer needs will drive these federations if they are to be successful. Cory Doctorow 's critique (" metacrap ")
3784-522: The Internet and are expected to be evolving almost constantly. Similarly, ontologies are typically far more flexible as they are meant to represent information on the Internet coming from all sorts of heterogeneous data sources. Class hierarchies on the other hand tend to be fairly static and rely on far less diverse and more structured sources of data such as corporate databases. The OWL languages are characterized by formal semantics . They are built upon
3872-444: The OWL family is interpreted as a set of "individuals" and a set of "property assertions" which relate these individuals to each other. An ontology consists of a set of axioms which place constraints on sets of individuals (called "classes") and the types of relationships permitted between them. These axioms provide semantics by allowing systems to infer additional information based on the data explicitly provided. A full introduction to
3960-464: The RDFS meaning, and OWL Full is a semantic extension of RDF. [The closed] world assumption implies that everything we don't know is false , while the open world assumption states that everything we don't know is undefined . The languages in the OWL family use the open world assumption . Under the open world assumption, if a statement cannot be proven to be true with current knowledge, we cannot draw
4048-739: The Semantic Web Activity in September 2007. In April 2008, this group decided to call this new language OWL2, indicating a substantial revision. OWL 2 became a W3C recommendation in October 2009. OWL 2 introduces profiles to improve scalability in typical applications. Why not be inconsistent in at least one aspect of a language which is all about consistency? OWL was chosen as an easily pronounced acronym that would yield good logos, suggest wisdom, and honor William A. Martin 's One World Language knowledge representation project from
4136-509: The Semantic Web. The World Wide Web Consortium (W3C) Incubator Group for Uncertainty Reasoning for the World Wide Web (URW3-XG) final report lumps these problems together under the single heading of "uncertainty". Many of the techniques mentioned here will require extensions to the Web Ontology Language (OWL) for example to annotate conditional probabilities. This is an area of active research. Standardization for Semantic Web in
4224-561: The Web, fundamentally the RDF. According to the W3C, "The Semantic Web provides a common framework that allows data to be shared and reused across application, enterprise, and community boundaries." The Semantic Web is therefore regarded as an integrator across different content and information applications and systems. The term was coined by Tim Berners-Lee for a web of data (or data web ) that can be processed by machines—that is, one in which much of
4312-425: The World Wide Web Consortium (" W3C "), which oversees the development of proposed Semantic Web standards. He defines the Semantic Web as "a web of data that can be processed directly and indirectly by machines". Many of the technologies proposed by the W3C already existed before they were positioned under the W3C umbrella. These are used in various contexts, particularly those dealing with information that encompasses
4400-699: The World Wide Web is based mainly on documents written in Hypertext Markup Language (HTML), a markup convention that is used for coding a body of text interspersed with multimedia objects such as images and interactive forms. Metadata tags provide a method by which computers can categorize the content of web pages. In the examples below, the field names "keywords", "description" and "author" are assigned values such as "computing", and "cheap widgets for sale" and "John Doe". Because of this metadata tagging and categorization, other computer systems that want to access and share this data can easily identify
4488-602: The World Wide Web. These included languages based on HTML (called SHOE ), based on XML (called XOL, later OIL ), and various frame-based KR languages and knowledge acquisition approaches. In 2000 in the United States, DARPA started development of DAML led by James Hendler . In March 2001, the Joint EU/US Committee on Agent Markup Languages decided that DAML should be merged with OIL. The EU/US ad hoc Joint Working Group on Agent Markup Languages
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#17327657678874576-486: The architecture of the Semantic Web. The functions and relationships of the components can be summarized as follows: Well-established standards: Not yet fully realized: The intent is to enhance the usability and usefulness of the Web and its interconnected resources by creating semantic web services , such as: Such services could be useful to public search engines, or could be used for knowledge management within an organization. Business applications include: In
4664-409: The basic feasibility of a complete or even partial fulfillment of the Semantic Web, pointing out both difficulties in setting it up and a lack of general-purpose usefulness that prevents the required effort from being invested. In a 2003 paper, Marshall and Shipman point out the cognitive overhead inherent in formalizing knowledge, compared to the authoring of traditional web hypertext : While learning
4752-512: The basics of HTML is relatively straightforward, learning a knowledge representation language or tool requires the author to learn about the representation's methods of abstraction and their effect on reasoning. For example, understanding the class-instance relationship, or the superclass-subclass relationship, is more than understanding that one concept is a "type of" another concept. [...] These abstractions are taught to computer scientists generally and knowledge engineers specifically but do not match
4840-576: The beginning, IS-A was quite simple. Today, however, there are almost as many meanings for this inheritance link as there are knowledge-representation systems. Early attempts to build large ontologies were plagued by a lack of clear definitions. Members of the OWL family have model theoretic formal semantics, and so have strong logical foundations. Description logics are a family of logics that are decidable fragments of first-order logic with attractive and well-understood computational properties. OWL DL and OWL Lite semantics are based on DLs. They combine
4928-544: The concept of decentralized autonomous organizations (DAOs). Decentralized finance (DeFi) is another key concept; in it, users exchange currency without bank or government involvement. Self-sovereign identity allows users to identify themselves without relying on an authentication system such as OAuth , in which a trusted party has to be reached in order to assess identity. Academic researchers, such as Tomer J. Chaffer and Justin Goldston in 2022, have described Web3 as
5016-455: The content, i.e., to describe the structure of the knowledge we have about that content. In this way, a machine can process knowledge itself, instead of text, using processes similar to human deductive reasoning and inference , thereby obtaining more meaningful results and helping computers to perform automated information gathering and research. An example of a tag that would be used in a non-semantic web page: Encoding similar information in
5104-458: The context of Web 3.0 is under the care of W3C. The term "Semantic Web" is often used more specifically to refer to the formats and technologies that enable it. The collection, structuring and recovery of linked data are enabled by technologies that provide a formal description of concepts, terms, and relationships within a given knowledge domain . These technologies are specified as W3C standards and include: The Semantic Web Stack illustrates
5192-543: The cyber-libertarian views and hopes of the past that the internet can empower ordinary people by breaking down existing power structures". Some other critics of Web3 see the concept as a part of a cryptocurrency bubble , or as an extension of blockchain -based trends that they see as overhyped or harmful, particularly NFTs . Some critics have raised concerns about the environmental impact of cryptocurrencies and NFTs. Cryptocurrencies vary in efficiency, with proof of stake having been designed to be less energy intensive than
5280-547: The data on the Web ;– the content, links, and transactions between people and computers. A "Semantic Web", which makes this possible, has yet to emerge, but when it does, the day-to-day mechanisms of trade, bureaucracy and our daily lives will be handled by machines talking to machines. The " intelligent agents " people have touted for ages will finally materialize. The 2001 Scientific American article by Berners-Lee, Hendler , and Lassila described an expected evolution of
5368-495: The data should point to additional URLs with data. Tags , including hierarchical categories and tags that are collaboratively added and maintained (e.g. with folksonomies ) can be considered part of, of potential use to or a step towards the semantic Web vision. Unique identifiers , including hierarchical categories and collaboratively added ones, analysis tools (e.g. scite.ai algorithms) and metadata , including tags, can be used to create forms of semantic webs – webs that are to
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#17327657678875456-488: The existing Web to a Semantic Web. In 2006, Berners-Lee and colleagues stated that: "This simple idea…remains largely unrealized". In 2013, more than four million Web domains (out of roughly 250 million total) contained Semantic Web markup. In the following example, the text "Paul Schuster was born in Dresden" on a website will be annotated, connecting a person with their place of birth. The following HTML fragment shows how
5544-447: The expressive power of the OWL is provided in the W3C's OWL Guide . OWL ontologies can import other ontologies, adding information from the imported ontology to the current ontology. An ontology describing families might include axioms stating that a "hasMother" property is only present between two individuals when "hasParent" is also present, and that individuals of class "HasTypeOBlood" are never related via "hasParent" to members of
5632-552: The expressiveness constraints placed on OWL Lite amount to little more than syntactic inconveniences: most of the constructs available in OWL DL can be built using complex combinations of OWL Lite features, and is equally expressive as the description logic S H I F ( D ) {\displaystyle {\mathcal {SHIF}}(\mathbf {D} )} . Development of OWL Lite tools has thus proven to be almost as difficult as development of tools for OWL DL, and OWL Lite
5720-412: The figure) allow to infer the following triple, given OWL semantics (red dashed line in the second Figure): The concept of the semantic network model was formed in the early 1960s by researchers such as the cognitive scientist Allan M. Collins , linguist Ross Quillian and psychologist Elizabeth F. Loftus as a form to represent semantically structured knowledge. When applied in the context of
5808-441: The future of the internet". Some Web 2.0 companies, including Reddit and Discord , have explored incorporating Web3 technologies into their platforms. On November 8, 2021, CEO Jason Citron tweeted a screenshot suggesting Discord might be exploring integrating cryptocurrency wallets into their platform. Two days later, and after heavy user backlash, Discord announced they had no plans to integrate such technologies and that it
5896-532: The given URI. In this example, all URIs, both for edges and nodes (e.g. http://schema.org/Person , http://schema.org/birthPlace , http://www.wikidata.org/entity/Q1731 ) can be dereferenced and will result in further RDF graphs, describing the URI, e.g. that Dresden is a city in Germany, or that a person, in the sense of that URI, can be fictional. The second graph shows the previous example, but now enriched with
5984-489: The idea of Web3 gained popularity. Particular interest spiked toward the end of 2021, largely due to interest from cryptocurrency enthusiasts and investments from high-profile technologists and companies. Executives from venture capital firm Andreessen Horowitz traveled to Washington, DC , in October 2021 to lobby for the idea as a potential solution to questions about regulation of the web, with which policymakers have been grappling. Specific visions for Web3 differ, and
6072-419: The knowledge in an ontology) exist for these DLs. OWL Full is intended to be compatible with RDF Schema (RDFS), and to be capable of augmenting the meanings of existing Resource Description Framework (RDF) vocabulary. A model theory describes the formal semantics for RDF. This interpretation provides the meaning of RDF and RDFS vocabulary. So, the meaning of OWL Full ontologies are defined by extension of
6160-485: The letters logic above. OWL Full is based on a different semantics from OWL Lite or OWL DL, and was designed to preserve some compatibility with RDF Schema. For example, in OWL Full a class can be treated simultaneously as a collection of individuals and as an individual in its own right; this is not permitted in OWL DL. OWL Full allows an ontology to augment the meaning of the pre-defined (RDF or OWL) vocabulary. OWL Full
6248-778: The links between them. RDF, OWL, and XML, by contrast, can describe arbitrary things such as people, meetings, or airplane parts. These technologies are combined in order to provide descriptions that supplement or replace the content of Web documents. Thus, content may manifest itself as descriptive data stored in Web-accessible databases , or as markup within documents (particularly, in Extensible HTML ( XHTML ) interspersed with XML, or, more often, purely in XML, with layout or rendering cues stored separately). The machine-readable descriptions enable content managers to add meaning to
6336-426: The metaverse did not really welcome everyone, because owners of NFT virtual real estate on sites such as Decentraland could keep people out who did not have the assets. Web Ontology Language The Web Ontology Language ( OWL ) is a family of knowledge representation languages for authoring ontologies . Ontologies are a formal way to describe taxonomies and classification networks, essentially defining
6424-399: The modern internet, it extends the network of hyperlinked human-readable web pages by inserting machine-readable metadata about pages and how they are related to each other. This enables automated agents to access the Web more intelligently and perform more tasks on behalf of users. The term "Semantic Web" was coined by Tim Berners-Lee , the inventor of the World Wide Web and director of
6512-569: The more widely used proof of work , although there is disagreement about how secure and decentralized this is in practice. Others have expressed beliefs that Web3 and the associated technologies are a pyramid scheme . Jack Dorsey , co-founder and former CEO of Twitter , dismissed Web3 as a "venture capitalists' plaything". Dorsey opined that Web3 will not democratize the internet, but it will shift power from players like Facebook to venture capital funds like Andreessen Horowitz . Liam Proven, writing for The Register , concludes that Web3
6600-428: The name abstract syntax may be somewhat misleading. This syntax closely follows the structure of an OWL2 ontology. It is used by OWL2 to specify semantics, mappings to exchange syntaxes and profiles. Syntactic mappings into RDF are specified for languages in the OWL family. Several RDF serialization formats have been devised. Each leads to a syntax for languages in the OWL family through this mapping. RDF/XML
6688-475: The name of the node where the edge ends or a literal value (e.g. a text, a number, etc.). The triples result in the graph shown in the given figure . One of the advantages of using Uniform Resource Identifiers (URIs) is that they can be dereferenced using the HTTP protocol. According to the so-called Linked Open Data principles, such a dereferenced URI should result in a document that offers further data about
6776-668: The new web resembles the old web. An Ad Age article from 2022 stated "early adopters want to make a new internet that alleviates the problems of the old one" but said if companies put the same type of people in charge as on the earlier version, and those people had similar attitudes, the same problems would happen. Another article in the same issue of the magazine quoted Alex Smeele, co-founder of Non-Fungible Labs, who said companies that wanted to participate in Web3 were "actually going to have to rethink their entire business model." Ana Constantino, founder of meetup platform Nowhere, said
6864-422: The physical and digital worlds". Some of the challenges for the Semantic Web include vastness, vagueness, uncertainty, inconsistency, and deceit. Automated reasoning systems will have to deal with all of these issues in order to deliver on the promise of the Semantic Web. This list of challenges is illustrative rather than exhaustive, and it focuses on the challenges to the "unifying logic" and "proof" layers of
6952-476: The relevant values. With HTML and a tool to render it (perhaps web browser software, perhaps another user agent ), one can create and present a page that lists items for sale. The HTML of this catalog page can make simple, document-level assertions such as "this document's title is 'Widget Superstore ' ", but there is no capability within the HTML itself to assert unambiguously that, for example, item number X586172
7040-526: The semantics of objects such as items for sale or prices. Microformats extend HTML syntax to create machine-readable semantic markup about objects including people, organizations, events and products. Similar initiatives include RDFa , Microdata and Schema.org . The Semantic Web takes the solution further. It involves publishing in languages specifically designed for data: Resource Description Framework (RDF), Web Ontology Language (OWL), and Extensible Markup Language ( XML ). HTML describes documents and
7128-422: The similar natural language meaning of being a "type of" something. Effective use of such a formal representation requires the author to become a skilled knowledge engineer in addition to any other skills required by the domain. [...] Once one has learned a formal representation language, it is still often much more effort to express ideas in that representation than in a less formal representation [...]. Indeed, this
7216-454: The structure of knowledge for various domains: the nouns representing classes of objects and the verbs representing relations between the objects. Ontologies resemble class hierarchies in object-oriented programming but there are several critical differences. Class hierarchies are meant to represent structures used in source code that evolve fairly slowly (perhaps with monthly revisions) whereas ontologies are meant to represent information on
7304-407: The term has been described by Olga Kharif as "hazy", but they revolve around the idea of decentralization and often incorporate blockchain technologies, such as various cryptocurrencies and non-fungible tokens (NFTs). Kharif has described Web3 as an idea that "would build financial assets, in the form of tokens, into the inner workings of almost anything you do online". A policy brief published by
7392-441: The things people don't like about the current internet, even when it's contradictory." Grimmelmann also argued that moving the internet toward a blockchain-focused infrastructure would centralize and cause more data collection compared to the current internet. Software engineer Stephen Diehl described Web3 in a blog post as a "vapid marketing campaign that attempts to reframe the public's negative associations of crypto assets into
7480-429: The vast majority of users were consumers, not producers of content. Web 2.0 is based around the idea of "the web as platform" and centers on user-created content uploaded to forums , social media and networking services, blogs , and wikis , among other services. Web 2.0 is generally considered to have begun around 2004 and continues to the current day. Web3 is distinct from Tim Berners-Lee 's 1999 concept of
7568-643: The working group was disbanded on May 31, 2004. In 2005, at the OWL Experiences And Directions Workshop a consensus formed that recent advances in description logic would allow a more expressive revision to satisfy user requirements more comprehensively whilst retaining good computational properties. In December 2006, the OWL1.1 Member Submission was made to the W3C. The W3C chartered the OWL Working Group as part of
7656-445: Was an internal-only concept that had been developed in a company-wide hackathon . Some legal scholars quoted by The Conversation have expressed concerns over the difficulty of regulating a decentralized web, which they reported might make it more difficult to prevent cybercrime , online harassment , hate speech , and the dissemination of child pornography . But, the news website also states that, "[decentralized web] represents
7744-565: Was convened to develop DAML+OIL as a web ontology language. This group was jointly funded by the DARPA (under the DAML program) and the European Union's Information Society Technologies (IST) funding project. DAML+OIL was intended to be a thin layer above RDFS , with formal semantics based on a description logic (DL). DAML+OIL is a particularly major influence on OWL; OWL's design was specifically based on DAML+OIL. The Semantic Web provides
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