Linked open EP data
The Cooperative Patent Classification (CPC) was initiated as a joint partnership between the United States Patent and Trademark Office (USPTO) and the European Patent Office (EPO) where the Offices have agreed to harmonize their existing classification systems (USPC and ECLA, respectively) and migrate towards a common classification scheme.
The EP Linked Data Service publishes a linked data representation of the CPC classification scheme. The CPC ontology defines the classes and properties used to describe the linked data representation of CPC. For more information about CPC see the CPC website.
The current linked data representation of CPC includes all the CPC scheme and concordance data with the World Intellectual Property Organization's International Patent Classification scheme (IPC). It does not include the CPC Definitions.
The prefix normally used for terms in the CPC ontology is
cpc:. The ontology namespace is
http://data.epo.org/linked-data/def/cpc/. Terms related to IPC are defined in the namespace
http://data.epo.org/linked-data/def/ipc/ with the normal prefix ipc:. The URLs identifying all terms in the CPC ontology dereference and are also described in the cpc ontology reference page.
An overview of the major classes in the CPC ontology is given in the following diagram:
The CPC classification scheme defines a hierarchy of classifications. The CPC ontology uses the Simple Knowledge Organization System (SKOS) as a base ontology which it extends. SKOS is a mature well known base ontology which is widely used for representing classification hierarchies, taxonomies and controlled vocabularies.
The central concept in the CPC ontology is cpc:Classification. cpc:Classification is a subclass of skos:Concept. Each instance of cpc:Classification is a node in the CPC classification hierarchy. For example A01B1/16 is a classification node in the CPC hierarchy.
Classifications in the hierarchy are linked to their higher and lower classifications by the SKOS semantic relation properties skos:broader and skos:narrower respectively.
The property cpc:symbol relates a CPC classification to its symbol, e.g. "A01B1/16". The property cpc:sortKey relates a CPC classification to a key that may be used for ordering classifications. The property cpc:level takes an integer value indicating the level of a classification in the hierarchy.
Each classification has three title properties providing different variations of its title:
The resource cpc:scheme represents the scheme as a whole. cpc:scheme is linked to the top level CPC classifications with the property skos:hasTopConcept and the top level concepts are related to the scheme with the property skos:topConceptOf.
Roughly, cpc:scheme corresponds to level 1 of the CPC hierarchy. The following sub-classes of cpc:Classification correspond to classifications at lower levels:
CPC level 6 corresponds to the class cpc:GuidanceHeading. Guidance Headings are annotations, information for the CPC user and so they are not represented as classifications. The property cpc:guidanceHeading links a main group to its guidance heading, if there is one.
Many classifications in CPC are concordant with classifications in IPC. The property cpc:concordantIPC relates a CPC classification to its concordant IPC classification. The inverse property cpc:concordantCPC relates an IPC classification to its concordant IPC classification. The property ipc:symbol indicates the symbol used to identify an IPC classification.