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The Quality Ontology is used to represent the quality of information for data streams in smart cities. The annotated data streams are represented with the Stream Annotation Ontology. To provide information about the provenance of the streams parts of the PROV-O ontology are used.
This is a work in progress and changes may be made. Comments are very welcome, please send them to Editor. Thank you.
The Quality Ontology is optimised to get used in combination with the Stream Annotation Ontology. The figure below depicts the workflow with the combination of both ontologies and the inclusion of the Complex Event Service ontology as they are combined within the EU FP7 project CityPulse.
The figure below depicts the Quality Ontology in detail. It illustrates the combination with the SAO and the PROV-O. It allows to annotate StreamData of the SAO with Quality. The Quality itself has five categories with subcategories to describe the attributes of the annotated data stream regarding its quality. In addition it provides a concept of trustworthiness for data sources. This concept is realised by two additional object properties hasProvenance and hasReputation to link the StreamData with an Agent as the owner and its Reputation.
An alphabetical index of Quality Ontology terms, by class (concepts) and by property (relationships, attributes), are given below. All the terms are hyperlinked to their detailed description for quick reference.
The following example depicts a data stream segment for traffic data provided by the Open Data Aarhus platform.
@prefix : <http://ict-citypulse.eu/experiments/Experiment1/> . @prefix prov: <http://purl.org/NET/provenance.owl#> . @prefix qoi: <http://purl.oclc.org/NET/UASO/qoi/> . @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . @prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> . @prefix sao: <http://purl.oclc.org/NET/UNIS/sao/sao#> . @prefix ssn: <http://purl.oclc.org/NET/ssnx/ssn#> . @prefix tl: <http://purl.org/NET/c4dm/timeline.owl#> . @prefix xml: <http://www.w3.org/XML/1998/namespace> . @prefix xsd: <http://www.w3.org/2001/XMLSchema#> . :segment-sample-1 a sao:Segment ; qoi:hasQuality :age-sample-1, :completeness-sample-1, :correctness-sample-1, :frequency-sample-1 ; ssn:observationResultTime [ a tl:Interval ; tl:at "2014-08-01T09:00:00"^^xsd:dateTime ; tl:duration "PT00H05M"^^xsd:duration ] ; prov:hasProvenance :R_ID158355 . :age-sample-1 a qoi:Age ; qoi:value "1.0"^^xsd:float . :completeness-sample-1 a qoi:Completeness ; qoi:value "1.0"^^xsd:float . :correctness-sample-1 a qoi:Correctness ; qoi:value "0.99"^^xsd:float . :frequency-sample-1 a qoi:Frequency ; qoi:value "1.0"^^xsd:float . :R_ID158355 a prov:SoftwareAgent .
Accuracy - Category to describe the accuracy of stream data.
Age - The time an information was created/measured/sensed. Has a minimum value of 0.0 and cannot be negative.
Authority - Certificate authority.
Bandwidth - Min/Avrg/Max amount of bandwidth that is required to transport the stream. Has a minimum value of 0.0 and cannot be negative.
Completeness - Probability that provided data is within the range of precision and completeness. Completeness cannot be negative and only reach 1 (0-100%)
Confidentiality - The degree to which information has attributes that ensure that it is only accessible and interpretable by authorized users in a specific context of use.
Correctness - The ratio of attribute values compared to expected parameters. Correctness cannot be negative and only reach 1 (0-100%)
Cost - Category to describe the costs of a data stream.
Deviation - The maximum percentage of deviation from the real value. Deviation cannot be negative and only reach 1 (0-100%)
Encryption - Encryption method, authority for key management.
EnergyConsumption - The amount of energy used to access the steam. The EnergyConsumption cannot be negative.
Frequency - Maximum timespan between two data sets. The Frequency has to be greater 0 as it is a timespan.
Jitter - Deviation from true periodicity of an assumed periodic signal.Jitter cannot be negative.
Latency - Measure of the time delay between the stream is sent and received in the virtualisation layer. Latency cannot be negative.
LicenceDefinition - Reference to license class.
MayBePublished - Reference to permission class.
MayBeUsed - Reference to permission class.
MonetaryConsumption - Is the usage of the stream free of charge or how much does it cost. The MonetaryConsumption has to be greater or equal to 0.
NetworkConsumption - How much traffic is caused by usage of the data source. The NetworkConsumption cannot be negative.
NetworkPerformance - Category to describe QoS values of a data stream.
Ordered - Probability that data sets arrive in the defined queuing order. Ordered cannot be negative and only reach 1 (0-100%)
PacketLoss - The probability that a set of data / a packet will not be transported correctly from the source to its sink. PacketLoss cannot be negative and only reach 1 (0-100%)
Precision - Category for parameters describing the precision.
PublicKey - Key to decrypt signatures.
Quality - The Quality is the description of some values for the quality of a data stream.
Queuing - Describes the order of streaming information.
QueuingType - Queue Type, for example FIFO, LIFO, unordered.
Reputation - Reputation value to measure the trustworthiness of a data stream. Reputation cannot be negative and only reach 1 (0-100%)
Resolution - Resolution detail for the measured value. The Resoultion cannot be negative.
Security - This cetagory describes security and confidentiality related attributes of a data stream.
Signing - Used to describe parameters for signing.
Throughput - The amount of useful information sent by the network (e.g. sensor data), taking out the headers and protocol information sent in the network. Throughput cannot be negative.
Timeliness - Category to describe time related attributes of a data stream.
Volatility - The amount of time the information remains valid in the context of a particular activity. Volatility cannot be negative as it is a timespan.
hasAbsoluteQuality - Describes the absolute value of the measured quality.
hasProvenance - describes the provenance of an entity/data stream
hasQuality - describes the quality values an entity has
hasRatedQuality - Describes the rated value of the measured quality in comparison with the annotated stream description.
hasReputation - Describes the value range for the Reputation.
hasReputationValue - Describes the value range for the Reputation.
hasUnitOfMeasurement - Describes the measurement unit of the absolute measured quality.
Iggena, T., Kümper, D., Tönjes, R., Kontinuierliche Bewertung von Informationsqualität in Stream-basierten Smart City Architekturen. ITG-Fachbericht-Mobilkommunikation–Technologien und Anwendungen., Mai 2014, Osnabrück, Germany.
This work is part of the EU FP7 CityPulse project at the Lab for Mobile Communication University of Applied Sciences Osnabrück.