Word semantic representation of its meaning.
Things semantic meaning of things.
Semantic Web = Web significance.
What is the Semantic Web?
What is semantics? In fact, it simply is to let the machine can read the contents.
- The Beatles was a popular band from Liverpool.
- John Lennon is a member of the Beatles.
- "Hey Jude" by the Beatles masterpiece.
We can easily understand the meaning of the above sentence. But these statements are to understand how a computer it?
Statement was created by the rules of grammar. Syntax of the language defines the language statements to create rules. But how to get into a semantic grammar it?
Semantic Web is to be understood that the machine data. Semantic Web technology, which includes a description language and logical reasoning. It is through some form of package body (Ontology) will be described.
The Semantic Web is not a link between the pages.
Semantic Web describes the correlation between things ((eg A is part of B, Y is a member of Z) and the properties of things (such as size, height, age, price, etc.).
Semantic network is based on XML (Extensible Markup Language eXtensible Markup Langauge) language and the Resource Description Framework (RDF) to complete. XML is a tool for defining a markup language, which includes the XML declaration, the language used to define the syntax of DTD (document type declaration document type definition), description tags and a detailed description of the document itself. The document itself contains markup and content. RDF is used to express the content of the page.
Resource Description Framework
RDF (Resource Description Framework), that is, Resource Description Framework, a W3C recommended specification language used to describe the relationship between the information and resources on the WWW.
RDF (S) is an important part of the Semantic Web, which uses URI to identify different objects (including resource nodes, attribute type or attribute values) can be connected to a different URI, clearly express the relationship between objects.
Although the Semantic Web is a better network, but the implementation is a complex and huge project. The current architecture of the Semantic Web is under construction, the main need to support the following two aspects:To achieve (1) a data network
That is: through a harmonized set of data standards to improve information on the network a more thorough and more detailed labeling, the Semantic Web can make accurate identification information to distinguish the role of information and meaning to make more precise semantic web search complete, easier to judge information true or false, so as to achieve practical goals, you first need to develop standard, which allows users to add web content metadata (ie detailed explanation mark), and allows users to pinpoint what they are looking for; then, you also need to find One way to ensure that different programs can share different sites; and finally, ask the user can add other features, such as adding application software.
Semantic network is based on XML (Extensible Markup Language eXtensible Markup Langauge) language and the Resource Description Framework (RDF) to complete. XML is a tool for defining a markup language, which includes the XML declaration, the language used to define the syntax of DTD (document type declaration document type definition), description tags and a detailed description of the document itself. The document itself contains markup and content. RDF is used to express the content of the page.(2) having a semantic analysis of the ability of search engines
If the data network can achieve short by hundreds of millions of individuals, the semantic network intelligence through human effort is necessary to achieve the tip of the wisdom of crowds. Having the ability to develop a semantic analysis of information search engine will be the most important step of the Semantic Web, this engine can understand natural human language, and have some reasoning and judgment.
Semantic Search Engine (semantic search engine) and semantic analysis capabilities of search engines (semantically enabled search engine) are two different things. However, the former is the use of the Semantic Web, an information search, and semantic analysis capabilities is a search engine capable of understanding natural language, reasoning by the computer user and further provide a more psychological answers.
Architecture of the Semantic Web is under construction, the current international research within the scope of this architecture has not yet formed a satisfactory description of rigorous logic and theoretical system, Chinese scholars of the architecture is only done on the basis of foreign studies a brief introduction, have not formed a systematic exposition.
Semantic network needs three key technologies supported: XML, RDF and Ontology.
XML (eXtensible Marked Language, eXtensible Markup Language) allows information providers as necessary, define their own tags and attribute names, so that the complex structure of XML documents can be to any extent.
It has good data storage format and scalable, highly structured and easy network transmission, etc., coupled with its unique mechanism of NS and XML Schema supports multiple data types and checking mechanism, making it the Semantic Web one of the key technologies.
Current discussions on semantic gateway key technology focused on RDF and Ontology body.
RDF is a W3C-recommended language used to describe the relationship between resources and their specification, and has a simple, easy to expand, open, easily integrated and easy exchange and so on.
It is noteworthy that, RDF defines only way to describe the resources, but does not define what data describe resources available. RDF consists of three parts: RDF Data Model, RDF Schema and RDF Syntax.attach:
Semantic network through the expansion of existing Internet content added to the information indicating its meaning, so that the computer can automatically work with people. That is, the Semantic Web is no longer just a variety of resources connected to the information, but also the true meaning of its information, thereby improving the automation and intelligent computer processing information. Of course, the computer does not have a truly intelligent, semantic web researchers need to establish effective representation of the information, the development of uniform standards, so that the computer can automatically process information effectively.
(Source: Bin Zhang thick "Information Management Principles and Methods", Tsinghua University Press, July 2007 Second Edition)
Semantic Web Architecture
- The first layer: Unicode and URI, is the basis of the entire architecture.
- The second layer: XML + NS + XMLSchema, responsible for representing the contents and structure of the grammar data by using the standard form of the language format of network information, the data structure and content separate.
- The third layer: RDF + RDF Schema, which provides semantic models used to describe the type of information and the Internet. Wherein, RDF (Resource Description Framework), that is, Resource Description Framework, a W3C recommended specification language used to describe the relationship between the information and resources on the WWW. RDF (S) is an important part of the Semantic Web, which uses URI to identify different objects (including resource nodes, attribute type or attribute values) can be connected to a different URI, clearly express the relationship between objects.
- The fourth layer: a body lexical level, the body is conceptualized on the field of knowledge, explicit formal specification. Semantic Web architecture, the role of the body mainly in: (1) describe the concept, which describes the domain knowledge revealed through the concept; (2) semantic revealed body has more expressive power than RDF, can reveal more. rich semantic relationship; (3) the consistency of the body as a field of knowledge explicit norms to ensure semantic consistency, thus completely solve the polysemy, meaning a multi-word and meaning ambiguous phenomenon; (4) reasoning support , uncertainty and powerful semantic ontology reveals ability on the concepts described in the data level effectively ensure the validity of reasoning.
- Fifth layer: logical layer, is responsible for providing axioms and inference principles provide the basis for intelligent services. Among them, the description logic (DescriptionLogic) is based on the formal knowledge representation object, which draw the main ideas KL-ONE is a first-order predicate logic decidable subset. It is the first-order predicate logic is different, the system can provide a description logic decidable reasoning services. In addition to knowledge representation than describing logic are also used in many other areas, it is considered the most important is a normalized form of client-centered representation language. Important features described logic is very strong skills and determination of which ensures inference algorithm can always stop and return the correct results. In many formal methods of knowledge representation, the logic is described in more than a decade of particular concern, mainly because: they have a clear model - theoretical mechanism; well suited to be represented by the concept of taxonomy application areas; and provide reasoning service is very useful.
- The sixth and seventh layer layers prove trust layer is responsible for providing authentication and trust mechanisms.