IEC 62656-8:2020 pdf free download – Standardized product ontology register and transfer by data parcels
4.1 Holistic use scenario
A standardized ontology such as that set out in lEC 61360-4 consists of a standardized set ofclasses and properties which should be used for common understanding of the meaning ofdata among users. In most cases,such a standardized ontology contains a minimum agreedset of classes and properties expressed in the English language; therefore it usually needs tobe customized for actual use.For example, language translation may be important for the useof an ontology for non-native English users in a regional company.For another example,extensions of classes and properties,such as commercial data or administrative information,are essential for product information management in each company.The four modelling layersapproach defined in lEC 62656-1 allows for the representation of such an extension andmodification in data parcels.
Such a customized ontology is usually maintained and published in a server (e.g. applicationontology repository) such as a national server and an enterprise server， separately from theserver(e.g., common ontology repository) where the standardized ontology is stored. lf thereis a mechanism not only for downioading or uploading data parcels but also for subscription toan ontology by using the web technique, the use of a standardized ontology and its extensionwill be enhanced and made easy. Web services specified in this document will contribute toenabling the exchange of data parcel(s) of an ontology between a server and a client orbetween servers.
In many cases, data exchange both between servers and between a server and a client aredone over the HTTP(S) protocol,because there are many hardware，software and securitytechniques for it. Therefore，the use of the HTTP(S) protocol is recommended for a parcelweb service, but other protocols are also available for a data exchange by means of a parcelweb service for a specific requirement such as communication speed.
The web services for the exchange of or the subscription to data parcels defined in thisdocument presume, but are not limited to, the following use scenarios depicted in Figure 1.
A request is a message which is sent from a parcel client to a parcel server.The messagemay contain one or more parameters,each of which is used for executing a service on aparcel server.
A response is a message which is sent from a parcel server to a parcel client as a result ofexecuting a service.The message may contain the result of the inquiry from a parcel client.
An exception is an unexpected event which occurs during the executing of a parcel webservice. lf such an event occurs on a parcel server，and if information about the event ishelpful or meaningful for a parcel client, then an exceptional message will be thrown from theparcel server to the parcel client.This allows a parcel client to continue its flow of functionswhen a service fails. If an exception occurs during the processing of a function which a parcelclient requests to execute, the execution will be terminated and the parcel server will throwthe exception to the parcel client.
For a machine-readable description of web services,WADL (Web Application DescriptionLanguage)[6] and wsDL (Web Service Description Language)[7] are widely used.A WADLdescription for the services specified in Clause 5 is provided in Annex B,Clause B.1, while awsDL description for them is provided in Clause B.2.