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State of the Art in Smart Homes and Buildings
Published in Richard Zurawski, Industrial Communication Technology Handbook, 2017
Wolfgang Kastner, Lukas Krammer, Andreas Fernbach
DPWS does not offer a metamodel that can be used for information modeling. As the name implies, it is a profile that defines a subset of WS-* standards for the usage on resource constraint devices. For information modeling, DPWS does not come with a custom metamodeling language. For representing devices, process control variables, process data points, or the topology of a BAS XML schema can be used. XML schema is a metamodel that allows to define the structure of XML documents. It uses basic types, which are common in many other information modeling languages like xs:string, xs:decimal, xs:integer, xs:float, xs:float, xs:date, and xs:time, and further some XML-schema-specific basic types, which are QName, anyURI, language, ID, and IDREF. Basic types are neither allowed to contain subelements nor attributes. Furthermore, there are complex types, which may contain nested elements and attributes. It is possible to define value restrictions on XML types and also some requirements regarding the structure.
Extensible Markup Language Basics
Published in Giovanni Bartolomeo, Tatiana Kováčiková, Identification and Management of Distributed Data: NGN, Content-Centric Networks and the Web, 2016
Giovanni Bartolomeo, Tatiana Kováčiková
An XML schema document is itself a well-formed and valid XML document. The topmost element of this document is xs:schema. To associate a schema to a particular namespace, the attribute xs:targetNamespace is used. This attribute occurs inside the xs:schema element, and its value represents the URI of the namespace. Once a schema defined in an XML schema document is bound to a namespace, that namespace must be used to refer, from within another document, to the elements and the types defined in that schema. For instance, if the namespace http://example.org/calendar were associated to the example schema illustrated previously: <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" targetNamespace="http://example.org/calendar"> … </xs:schema>
General introduction
Published in Adedeji B. Badiru, Handbook of Industrial and Systems Engineering, 2013
Unlike DTD, XML schema is an XML-based language. It describes a model, which defines the possible arrangement of tags and text in a document. Since XML schema documents are XML documents, they can be edited and processed with the same tools that users use to process other XML documents. As opposed to DTD, XML schemas include a new range of features, including the following: (1) Richer data types, such as booleans, numbers, dates, and times; URIs; integers; decimal numbers; real numbers; and intervals of time. (2) User-defined types, called Archetypes, which allow users to define their own named data type. (3) Attribute grouping, which allow the schema author to make this relationship explicit. (4) Refinable archetypes, or "inheritance." A refinable content model is the middle ground: additional elements may be present but only if the schema defines what they are. (5) Namespace support (W3C, 1999).
A Multilayered Clustering Framework to build a Service Portfolio using Swarm-based algorithms
Published in Automatika, 2019
I. R. Praveen Joe, P. Varalakshmi
The following are the sources of the metadata of a web service XML Schema – For defining data types and structures.WSDL – For defining messages, message exchange patterns, interfaces and endpoints.WS-Policy – For declaring assertions for various qualities of service requirements, such as reliability, security, and transactions.WS-Addressing – For defining Web service endpoint references and associated message patterns.WS-MetadataExchange – For dynamically accessing XML, WSDL, and WS-Policy metadata when required.
Web service discovery with incorporation of web services clustering
Published in International Journal of Computers and Applications, 2023
Sunita Jalal, Dharmendra Kumar Yadav, Chetan Singh Negi
Web services are self-describing and loosely coupled software modules that can be published, discovered, and invoked over Internet using open standards such as XML, WSDL, UDDI, SOAP, REST, and HTTP [1]. It acts as an interface between a service implementation and client of that service. Figure 1 shows the basic web service architecture that contains three components: Service Provider, Service Requester, and Service Registry. Service Provider implements web service and publishes its description on the service registry. Service registry keeps information about service providers and their services. Universal Description, Discovery, and Integration (UDDI) is an open specification for service registry. It defines an XML schema-based data model for representing information. Data model specifies four key types of information: Business Entity, Business Service, Binding Template, and tModel. Business Entity keeps information about service provider. Business Service provides description of the service offered by the service provider. Binding Template expresses the binding information required to use a web service. tModel provides technical specification of the web service such as reference to the web service description document. A business entity can offer one or more business services. Each business service can provide one or more binding templates to use it. A binding template references to a tModel. UDDI uses SOAP messaging protocol and defines inquiry and publisher APIs. Publisher API offers functionalities to insert, delete, and update information related to business and its services. Inquiry API offers functionalities to search and retrieve service data. Nowadays Online web directories also keep information about web services. Service requester queries the service registry to find information about service providers and descriptions of their services. Then it retrieves binding details to invoke the web service that satisfies its requirements. Organizations can develop business applications with minimal custom code writing using the web services composition. Web services composition provides a way to develop composite web service by combining and coordinating a set of existing value-added web services. It offers adequate support for reusability and application integration within and across organizational boundaries [2].