Điện thoại di động giao thức viễn thông cho các mạng dữ liệu P7

XML, RDF, and CC/PPExtensible Markup Language (XML) describes a class of data objects called XML documents and partially describes the behavior of the computer programs that process them. XML is an application profile or restricted form of the Standard Generalized Markup Language (SGML). Resource Description Framework (RDF) can be used to create a general, yet extensible framework for describing user preferences and device capabilities. This information can be provided by the user to servers and content providers. The servers can use this information describing the user’s preferences to customize the service or content provided....
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Điện thoại di động giao thức viễn thông cho các mạng dữ liệu P7 Mobile Telecommunications Protocols For Data Networks. Anna Ha´ c Copyright  2003 John Wiley & Sons, Ltd. ISBN: 0-470-85056-6 7 XML, RDF, and CC/PPExtensible Markup Language (XML) describes a class of data objects called XML doc-uments and partially describes the behavior of the computer programs that process them.XML is an application profile or restricted form of the Standard Generalized MarkupLanguage (SGML). Resource Description Framework (RDF) can be used to create a general, yet extensibleframework for describing user preferences and device capabilities. This information can beprovided by the user to servers and content providers. The servers can use this informationdescribing the user’s preferences to customize the service or content provided. The abilityof RDF to reference profile information via URLs assists in minimizing the number ofnetwork transactions required to adapt content to a device, while the framework fits wellinto the current and future protocols. A Composite Capability/Preference Profile (CC/PP) is a collection of the capabilitiesand preferences associated with user and the agents used by the user to access the WorldWide Web. These user agents include the hardware platform, system software, and appli-cations used by the user. User agent capabilities and references can be thought of asmetadata or properties and descriptions of the user agent hardware and software.7.1 XML DOCUMENTXML documents are made up of storage units called entities, which contain either parsedor unparsed data. Parsed data is made up of characters, some of which form characterdata and some of which form markup. Markup encodes a description of the document’sstorage layout and logical structure. XML provides a mechanism to impose constraintson the storage layout and logical structure. A software module called an XML processor is used to read XML documents andprovide access to their content and structure. It is assumed that an XML processor isdoing its work on behalf of another module called the application. An XML processorreads XML data and provides the information to the application.112 XML, RDF, AND CC/PP The design goals for XML are• to be straightforwardly usable over the Internet,• to support a wide variety of applications,• to be compatible with SGML,• to create easy-to-write programs that process XML documents,• to keep the number of optional features in XML to the absolute minimum, ideally zero,• to have XML documents human-legible and reasonably clear,• to prepare XML design quickly,• to have the design of XML formal and concise,• to have XML documents that are easy to create,• to have terseness in XML markup of minimal importance. A data object is an XML document if it is well formed, which may be valid if itmeets certain further constraints. Each XML document has both a logical and a phys-ical structure. Physically, the document is composed of units called entities. An entitymay refer to other entities to cause their inclusion in the document. A document beginsin a root or document entity. Logically, the document is composed of declarations, ele-ments, comments, character references, and Processing Instructions (PIs), all of which areindicated in the document by explicit markup. The logical and physical structures mustnest properly. Matching the document production implies that it contains one or more elements, andthere is exactly one element, called the root or document element, no part of whichappears in the content of any other element. For all other elements, if the start-tag is inthe content of another element, the end-tag is in the content of the same element. Theelements, delimited by start- and end-tags, nest properly within each other. A parsed entity contains text, a sequence of characters, which may represent markupor character data. Characters are classified for convenience as letters, digits, or othercharacters. A letter consists of an alphabetic or syllabic base character or an ideographiccharacter. A Name is a token beginning with a letter or one of a few punctuation characters,and continuing with letters, digits, hyphens, underscores, colons, or full stops, togetherknown as name characters. The Name spaces assign a meaning to names containing coloncharacters. Therefore, authors should not use the colon in XML names except for namespac ...