439:: A Context Broker acts as the primary access points to context information for Context Consumers. NGSI-LD Entity information can be stored by the Context Broker itself, if it has been provided by a Context Producer using the Context Information Provision functionalities of the NGSI-LD API, or the Broker can request is from Context Sources using the Context Information Consumption functionalities of the NGSI-LD API. The Context Broker aggregates all NGSI-LD Entity information related to a request and returns the aggregated result to the Context Consumer. In the case of a subscription, it sends notifications whenever there are relevant changes, potentially as a result of receiving notifications from Context Sources. To find Context Sources that may have NGSI-LD Entities relevant to a Context Consumer request, the Context Broker uses the Context Source Discovery functionality of the NGSI-LD API implemented by the Registry Server.
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XML-based representation. The NGSI Context
Interfaces were adapted by the FI-WARE project, which developed the platform for the European Future Internet Public-Private-Partnership (PPP). The OMA NGSI Context Interfaces got an HTTP binding with a JSON representation, referred to as NGSIv1, which included both NGSI-9 and NGSI-10. In the course of FI-PPP the interfaces further evolved into NGSIv2, which became the key interface of the FIWARE platform. After the end of the FI-PPP in 2016, the FIWARE platform became the core of the FIWARE Open Source Community managed by the
582:. In 2017, the ETSI Industry Specification Group on cross-cutting Context Information Management (ETSI ISG CIM) was created to evolve the Context Information Interface, which resulted in the creation of NGSI-LD. The limitations of the original information model led to the specification of a broader model which derives from property graphs, explicitly including relationships between entities, on a par with entities themselves. ETSI ISG CIM continues to evolve the NGSI-LD Information Model and API. It publishes new versions of the specification once or twice a year.
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328:) that is supposed to exist in the real world, outside of the computational platform using NGSI-LD. This referent need not be something strictly physical (it could be a legal or administrative entity), nor self-contained (it may be a distributed system-level construct). Any instance of such an entity is supposed to be uniquely identified by an IRI, and characterized by reference to one or more NGSI-LD Entity Type(s). In property-graph language, it is a node.
421:: A Context Consumer consumes NGSI-LD Entities from a Context Broker (or possibly directly from a Context Source) using the Context Information Consumption functionalities of the NGSI-LD API.It can retrieve a specific NGSI-LD Entity or query relevant NGSI-LD Entities using synchronous requests. It can also subscribe for relevant NGSI-LD Entities and receive asynchronous notifications whenever there are changes in the requested NGSI-LD Entities.
433:: A Context Source makes NGSI-LD Entities available through the Context Information Consumption functionalities of the NGSI-LD API. To make the information discoverable for a Context Broker, it registers the kind of context information it can provide with a Registry Server using the Context Source Registration functionality of the NGSI-LD API.
450:
NGSI-LD Entity, or to the level that it can provide NGSI-LD Entities that have a certain Entity Type, possibly for a given geographic area. The
Context Source Discovery functionality of the NGSI-LD API allows the Context Broker (or possibly a Context Consumer) to find Context Sources that may have relevant NGSI-LD Entities.
449:
of
Context Information a Context Source can provide, but not actual values. The kind of context information can be provided on different granularity levels ranging from very detailed information, e.g. certain properties or relationships of a specific NGSI-LD Entity, to any information of a specific
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operations, concerned with
Provision (creating NGSI-LD Entities, and updating their Attributes), Consumption (querying NGSI-LD Entities) and Subscription (subscribing to specific information, under specified constraints, in order to be notified when matching Entities appear, carrying the specified
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is a directed link between a subject (starting point), that may be an NGSI-LD Entity, an NGSI-LD Property, or another NGSI-LD Relationship, and an object (end-point), that is an NGSI-LD Entity. A NGSI-LD Relationship from a
Property to an Entity can for example be used to express that the Property
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The NGSI-LD Context
Information Management API allows users to provide, consume and subscribe to context information in multiple scenarios and involving multiple stakeholders. It enables close to real-time access to information coming from many different sources (not only IoT data sources), named
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The architectural roles allow the implementation of different deployment architectures. In a centralized architectures, there is a central
Context Broker that stores the context information provided by Context Producers. In a distributed setting, all context information can be stored by Context
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in 2012, which is also the source of the acronym NGSI. The NGSI suite included NGSI-9 as the
Context Entity Discovery Interface and NGSI-10 as the Context Information Interface. The NGSI standard from OMA and its intermediary evolutions relied on a classical Entity–attribute–value model and an
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The API is designed to be agnostic to the architecture (central, distributed, federated or combinations thereof), so that applications which produce and consume information do not have to be tailored to the specifics of the system that distributes/brokers context information for them.
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The flexible information model allows the specification of any kind of entity. In order to allow interoperability between NGSI-LD users, standardized entities are collaboratively defined at Smart Data Models
Program and made available at its repository with an open-source license.
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is an instance that associates a characteristic, an NGSI-LD Value, to either an NGSI-LD Entity, an NGSI-LD Relationship or another NGSI-LD Property. Properties of properties are explicitly allowed and are encouraged e.g. to express the accuracy of a particular measured
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Sources. In a federated architecture, Context
Sources can again be Context Brokers that make aggregated information from a lower hierarchy level available. These architectures are not mutually exclusive, i.e. an actual deployment may combine them in different ways.
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operations, concerned with Registration (make a new source of context information available in the overall distributed system, by registering it) and Discovery (querying the system about what context sources have registered, which offer information of a specified
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class that is a subclass of either the NGSI-LD Entity, NGSI-LD Relationship, NGSI-LD Property or NGSI-LD Value classes defined in the NGSI-LD meta-model. NGSI-LD pre-defines a small number of types, but is otherwise open to any types defined by
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project recommends the use of NGSI-LD in their joint declaration and their technical commitments. The declaration has been endorsed and signed by 86 cities and public administrations from the EU, and is supported by many more companies and
445:: The Registry Server stores Context Source Registrations provided by Context Sources using the Context Source Registration functionalities of the NGSI-LD API. Context Source Registrations contain information about what
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The NGSI-LD information model represents Context Information as entities that have properties and relationships to other entities. It is derived from property graphs, with semantics formally defined on the basis of
427:: A Context Producer creates, updates and deletes NGSI-LD Entities, NGSI-LD Properties and NGSI-LD Relationships in the Context Broker using the Context Information Provision functionalities of the NGSI-LD API.
1009:
Bauer, Martin; Kovacs, Ernö; Schülke, Anett; Ito, Naoko; Criminisi, Carmen; Goix, Laurent-Walter; Valla, Massimo (2010). "2010 14th International Conference on Intelligence in Next Generation Networks".
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Properties (similar to attributes in object models) have the form of arbitrary key-value pairs. Keys are character strings and values are arbitrary data types. By contrast to RDF graphs, properties are
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which included Context Interfaces. These were taken up and evolved as NGSIv2 by the European Future Internet Public-Private-Partnership (PPP), which spawned the FIWARE open source community.
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It provides advanced geo-temporal queries, and it includes subscription mechanisms, in order for content consumers to be notified when content matching some constraints becomes available.
564:(IUDX) uses the NGSI-LD API as part of their Resource Access Service Interface. It is referenced in the Bureau of Indian Standards' Unified Data Exchange IS 18003(Part2):2021 standard.
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p.6, In today's Smart Cities "System-of-Systems" architectures are created on the basis of the ETSI standard "Context Information Management (ETSI ISG CIM)" also known as NGSI-LD.
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The NGSI-LD specification consists of an information model and an API. The API provides functionalities to support the architectural roles described in the following.
502:, and is primarily used by the FIWARE open source community, supported by the FIWARE Foundation as well as a diverse range of other projects and users such as below:
156:. It is meant to facilitate the open exchange and sharing of structured information between different stakeholders. It is used across application domains such as
195:. Its takeup and further development are spelled out in the EU's "Rolling plan for ICT standardization". NGSI-LD builds upon a decades-old corpus of research in
678:
Almeida, JoĂŁo; Silva, Jorge; Batista, Thais; Cavalcante, Everton (2020). "Proceedings of the 22nd International Conference on Enterprise Information Systems".
191:(European Telecommunications Standardization Institute) through the Context Information Management Industry Specification Group, following a request from the
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NGSI-LD is the result of an evolution of Context Interfaces that started as part of the "Next Generation Service Interfaces" (NGSI) suite published by the
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frameworks and context modelling. The acronym NGSI stands for "Next Generation Service Interfaces", a suite of specifications originally issued by the
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The City Data Hub platform has been developed as part of the Smart City Data Hub project and is now used as a basis for smart cities in Korea.
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Bettini, Claudio; Brdiczka, Oliver; Henricksen, Karen; Indulska, Jadwiga; Nicklas, Daniela; Ranganathan, Anand; Riboni, Daniele (2010).
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517:(OASC) organisation references the NGSI-LD specification as the first of their Minimal Interoperability Mechanisms (MIM1).
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connected by directed links, where nodes and arcs both may have multiple optional attached properties (i.e. attributes)
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Detti, Andrea; Tropea, Giuseppe; Rossi, Giulio; Martinez, Juan A.; Skarmeta, Antonio F.; Nakazato, Hidenori (2019).
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of the property graph model, which has emerged since the early 2000s as an informal common denominator model for
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Cirillo, Flavio; Solmaz, GĂĽrkan; Berz, Everton LuĂs; Bauer, Martin; Cheng, Bin; Kovacs, Ernö (September 2019).
799:"Mapping the NGSI-LD Context Model on Top of a SPARQL Event Processing Architecture: Implementation Guidelines"
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that defines key constructs related to spatial, temporal or system-composition characteristics of entities.
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Context Sources, as well as publishing that information through interoperable data publication platforms.
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1221:"Virtual IoT Systems: Boosting IoT Innovation by Decoupling Things Providers and Applications Developers"
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Complementing this metamodel, the NGSI-LD information model specification also provides a cross-domain
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Viola, Fabio; Antoniazzi, Francesco; Aguzzi, Cristiano; Kamienski, Carlos; Roffia, Luca (April 2019).
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539:, where it is used as a neutral data format for translating between various IoT data representations
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Proceedings of the 14th International Conference on Intelligence in Next Generation Networks (ICIN)
805:. 24th Conference of Open Innovations Association (FRUCT). Moscow, Russia: IEEE. pp. 493–501.
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formally defines these foundational concepts (Entities, Relationships, Properties) on the basis of
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typed value (i.e. a string as the lexical form of the value together with a type, defined by an
621:"City Data Hub: Implementation of Standard-Based Smart City Data Platform for Interoperability"
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Ulrich Ahle; Ernö Kovacs; Andreas Linneweber; Wolfgang Möller; Bernd Simon. (October 2020).
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Proceedings of the 22nd International Conference on Enterprise Information Systems (ICEIS)
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LĂłpez-Morales, Juan Antonio; Martinez, Juan Antonio; Skarmeta, Antonio F. (2020-01-24).
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The NGSI-LD information model can be considered as the first formal specification by a
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datasets. The -LD suffix denotes this affiliation to the linked data universe.
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value (i.e. a string, a number, true or false, an object, an array), or a
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reference as identifier, making the corresponding data exportable as
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structured value (i.e. a set, a list, or a language-tagged string).
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JosĂ© Manuel Cantera Fonseca, FermĂn Galán Márquez, Tobias Jacobs.
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2019 24th Conference of Open Innovations Association (FRUCT)
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Jeong, Seungmyeong; Kim, Seongyun; Kim, Jaeho (2020-12-07).
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recommends the use of the FIWARE context broker with NGSI-LD
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532:"IoT Big Data Framework Architecture" is based on NGSI-LD.
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NGSI-LD - A graph-based context information model and API
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Validation of NGSI-LD test Platform and Examples of uses
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is the informational representative of something (a
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219:. Every entity and relationship is given a unique
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515:Open & Agile Smart Cities & Communities
964:"EU 2021 rolling plan for ICT Standardisation"
953:"EU 2016 rolling plan for ICT standardisation"
59:ISG CIM (Industry Specification Group) of ETSI
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682:. Vol. 1. SciTePress. pp. 205–212.
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1067:: CS1 maint: multiple names: authors list (
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498:NGSI-LD was initiated by partners of the
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1098:NGSI-LD information model specification
1014:. Berlin, Germany: IEEE. pp. 1–5.
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215:framework. It can be serialized using
1208:"IoT Big Data Framework Architecture"
720:. Open Agile Smart Cities. 2019-12-11
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1082:"The Property Graph Database Model"
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286:Relationships are arcs (directed
264:(a.k.a. "attributed graph") is a
187:NGSI-LD has been standardized by
850:IEEE Internet of Things Magazine
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310:, and partially on the basis of
1169:Living-eu technical commitments
367:base type or more generally an
1366:City Data Hub Data Core Module
1225:2019 Global IoT Summit (GIoTS)
1048:"FIWARE-NGSI v2 Specification"
981:Pervasive and Mobile Computing
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344:was measured by that Entity (
168:, and more generally for the
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1195:"Supporting the declaration"
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993:10.1016/j.pmcj.2009.06.002
575:Open Mobile Alliance (OMA)
508:Connecting Europe Facility
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872:10.1109/IOTM.0001.1800022
562:India Urban Data Exchange
474:API operations comprise:
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1321:ETSI CIM group home page
689:10.5220/0009422802050212
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933:Internet of Things Show
256:The core concepts are:
247:standards organization
174:cyber-physical systems
120:CIM group page @ETSI
597:Graph Query Language
348:of the measurement).
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1265:"Information Model"
756:2020Senso..20.1153L
714:"NGSI-LD Resources"
637:2020Senso..20.7000J
479:Context Information
271:, made up of nodes
193:European Commission
153:context information
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1183:. 6 December 2019.
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283:arcs of the graph.
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