Please report any errors to the Semantic Sensor Network Incubator Activity via the public W3C list public-xg-ssn@w3.org
This ontology is developed by the W3C Semantic Sensor Networks Incubator Group (SSN-XG). The concepts and structure of the ontology were discussed in the group's meetings and on the mailing list. For more information on the group's activities see: http://www.w3.org/2005/Incubator/ssn/
This ontology describes sensors and observations, and related concepts. It does not describe domain concepts, time, locations, etc. these are intended to be included from other ontologies via OWL imports.
Any information that is provided to a process for its use [MMI OntDev]
The ability of a measurement to match the actual value of the quantity being measured [Haby 2008]
Note that, unlike some defintions of "event," this definition does not specify that an event involves a change of state, nor does it attempt to distinguish events from processes or states.
An event consists of some temporal and spatial boundaries subjectively imposed on the flux of reality or imagination, that we wish to treat as an entity for the purposes of making statements about it. In particular, we may wish to make statements that relate people, places, or things to an event [LODE].
Also corresponds to Observed Value [SensorML]: a value describing a natural phenomenon, which may use one of a variety of scales including nominal, ordinal, ratio and interval. The term is used regardless of whether the value is due to an instrumental observation, a subjective assignment or some other method of estimation or assignment.
Corresponds to measurement result [VIM 2.9] which is a set of quantity values being attributed to a measurand together with any other available relevant information. A quantity value is a number and reference together expressing magnitude of a quantity.
A sensing device is a device that implements sensing. [SSN XG]
The Measurement Range (measuring interval in [VIM 4.7]) is a set of values of quantities of the same kind that can be measured by a given measuring instrument or measuring system with specified instrumental uncertainty, under defined conditions.
(alternative definition) The Measurement Range (operating range in [Singh et al. 2010]) of a monitoring tool is defined as the minimum and maximum limiting value that it can measure.
Sensing is a process that results in the estimation, or calculation, of the value of a phenomenon. [SSN XG]
The ability of a measurement to be consistently reproduced”, i.e. it is the ability of repeatability [Haby 2008]
Sensitivity is the quotient of the change in an indication of a measuring system and the corresponding change in a value of a quantity being measured [VIM 4.12]
A device is a physical piece of technology - a system in a box. Devices may of course be built of smaller devices and software components (i.e. systems have components). [SSN XG]
Association of an entity to another entity (as for example, a device to a parent platform, or to an observation campaign), for a determinable period of time [MMI OntDev]
An observation is an act associated with a discrete time instant or period through which a number, term or other symbol is assigned to a phenomenon. It involves application of a specified procedure, such as a sensor, instrument, algorithm or process chain. The procedure may be applied in-situ, remotely, or ex-situ with respect to the sampling location. The result of an observation is an estimate of the value of a property of some feature [ISO/DIS 19156].
An observation is an event that estimates an observed property of some feature of interest using a specified procedure and generates a result [O&M]. An observation is the record of some sensing and contains time stamps, a result, a reference to the sensing process i.e. all the bits in O&M. [SSN XG]
A feature is an abstraction of real world phenomena [ISO 19101]
Selectivity is a property of a measuring system, used with a specified measurement procedure, whereby it provides measured quantity values for one or more measurands such that the values of each measurand are independent of other measurands or other quantities in the phenomenon, body, or substance being investigated [VIM 4.13]
System is a unit of abstraction for pieces of infrastructure (and we largely care that they are) for sensing. A system has components, its subsystems, which are other systems. [SSN XG]
The (instrumental) drift is a continuous or incremental change over time in indication, due to changes in metrological properties of a measuring instrument [VIM 4.21].
Any information that is reported from a process. [MMI OntDev]
The response time is the duration between the instant when an input quantity value of a measuring instrument or measuring system is subjected to an abrupt change between two specified constant quantity values and the instant when a corresponding indication settles within specified limits around its final steady value [VIM 4.25].
Represents capabilities associated with the measurements that a Sensor is able to produce. Such capabilities (modeled as subclasses) include Accuracy, Precision, Frequency, and ResponseTime. [MMI OntDev]
http://www.opengeospatial.org/standards/sensorml OGC-0700
Also an entity to which can be attached sensors or other platforms. A platform has an associated local coordinate frame that can be referenced to an external coordinate reference frame and to which the frames of attached sensors and platforms can be referenced [SensorML].
A common role for a spatial sampling feature is to host instruments or procedures deployed repetitively or permanently [O&M].
A process has an output and possibly inputs and, for a composite process, describes the temporal and dataflow dependencies and relationships amongst its parts. [SSN XG]
Resolution is the smallest change in a quantity being measured that causes a perceptible change in the corresponding indication [VIM 4.14]
The Detection Limit is a measured quantity value, obtained by a given measurement procedure, for which the probability of falsely claiming the absence of a component in a material is β, given a probability α of falsely claiming its presence [VIM 4.18]
A property is a facet or attribute of an object referenced by a name [O&M], [ISO 19143:2010, definition 4.21].
A property of an object is some intrinsic or extrinsic quality of that object, where the nature of the "object" in question will depend on the field, as, for example, indicated below.Material properties, Chemical properties, Physical properties, Thermodynamic properties, Mental properties. In information processing, properties are qualities of objects which are transmitted and then received by observers. Generally, properties allow an observer to distinguish one object from another [Wikipedia].
A sensor can do (implements) sensing. [SSN XG]
Corresponds to result quality [O&M]: If present, the result quality shall describe the quality of the result. This instance-specific description complements the description of the observation procedure, which provides information concerning the quality of all observations using this procedure. Quality of a result may be assessed following the procedures in ISO 19114. Multiple measures may be provided (ISO/TS 19138:2006).
The result time is the time when the procedure associated with the observation act was applied.
The result time shall describe the time when the result became available, typically when the procedure associated with the observation was completed For some observations this is identical to the phenomenonTime. However, there are important cases where they differ.[O&M]
The feature of interest of the initial observation of a type that carries the observed property within its properties [ISO/DIS 19156]. The feature of interest is a feature of any type (ISO 19109, ISO 19101), which is a representation of the observation target, being the real-world object regarding which the observation is made.[SemSOS]
The observation model maps the result of the application of a procedure to a subject, which plays the role of feature-of-interest of the observation (Clause 6). However, the proximate feature of interest of an observation may not be the ultimate domain-specific feature whose properties are of interest in the investigation of which the observation is a part. There are two circumstances that can lead to this: (i) the observation does not obtain values for the whole of a domain feature; (ii) the observation procedure obtains values for properties that are not characteristic of the type of the ultimate feature. Furthermore, in some practical situations, both differences apply [ISO/DIS 19156].
Rebadged as phenomenon time in [O&M]. The phenomenon time shall describe the time that the result applies to the property of the feature-of-interest. This is often the time of interaction by a sampling procedure or observation procedure with a real-world feature.
The sampling time is the time that the result applies to the feature-of-interest. This is the time usually required for geospatial analysis of the result.
The observedProperty identifies or describes the phenomenon for which the observation result provides an estimate of its value. It must be a property associated with the type of the feature of interest [SemSOS]. @Note: Corresponds to Measurand [VIM 2.3] which is the quantity intended to be measured. Note: The specification of a measurand requires knowledge of the kind of quantity, description of the state of the phenomenon, body, or substance carrying the quantity, including any relevant component, and the chemical entities involved.
A (measurement) procedure is a detailed description of a measurement according to one or more measurement principles and to a given measurement method, based on a measurement model and including any calculation to obtain a measurement result [VIM 2.6]
The (measurement) result [VIM 2.9] is a set of quantity values being attributed to a measurand together with any other available relevant information