Semantic Sensor Network Ontology
type: Ontology
creator: W3C Semantic Sensor Network Incubator Group
comment: Please report any errors to the Semantic Sensor Network Incubator Activity via the public W3C list public-xg-ssn@w3.org
modified: 2011-06-20
license: copyright-software-20021231.html
comment: 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/
rights: Copyright 2009 - 2011 W3C.
comment: 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.
created: 2009-12-02

attached system
type: ObjectProperty
sub property of: isLocationOf
inverse of: on platform
comment: Relation between a Platform and any Systems (e.g., Sensors) that are attached to the Platform.

deployed on platform
type: ObjectProperty
sub property of: hasParticipant
inverse of: in deployment
comment: Relation between a deployment and the platform on which the system was deployed.

deployed system
type: ObjectProperty
sub property of: hasParticipant
inverse of: has deployment
comment: Relation between a deployment and the deployed system.

deployment process part
type: ObjectProperty
sub property of: hasPart
comment: Has part relation between a deployment process and its constituent processes.

detects
type: ObjectProperty
comment: A relation from a sensor to the Stimulus that the sensor can detect. The Stimulus itself will be serving as a proxy for (see isProxyOf) some observable property.

end time
type: ObjectProperty
sub property of: hasRegion

feature of interest
type: ObjectProperty
sub property of: isSettingFor
source: skos:exactMatch 'featureOfInterest' [O&M - ISO/DIS 19156] http://portal.opengeospatial.org/files/?artifact_id=41579
comment: A relation between an observation and the entity whose quality was observed. For example, in an observation of the weight of a person, the feature of interest is the person and the quality is weight.

for property
type: ObjectProperty
comment: A relation between some aspect of a sensing entity and a property. For example, from a sensor to the properties it can observe, or from a deployment to the properties it was installed to observe. Also from a measurement capability to the property the capability is described for. (Used in conjunction with ofFeature).

has deployment
type: ObjectProperty
sub property of: isParticipantIn
comment: Relation between a System and a Deployment, recording that the System/Sensor was deployed in that Deployment.

has input
type: ObjectProperty

has measurement capability
type: ObjectProperty
sub property of: has property
comment: Relation from a Sensor to a MeasurementCapability describing the measurement properties of the sensor.

has measurement property
type: ObjectProperty
sub property of: has property
comment: Relation from a MeasurementCapability to a MeasurementProperty. For example, to an accuracy (see notes at MeasurementCapability).

has operating property
type: ObjectProperty
sub property of: has property
comment: Relation from an OperatingRange to a Property. For example, to a battery lifetime.

has operating range
type: ObjectProperty
sub property of: has property
comment: Relation from a System to an OperatingRange describing the normal operating environment of the System.

has output
type: ObjectProperty

has property
type: ObjectProperty
sub property of: hasQuality
inverse of: is property of
comment: A relation between a FeatureOfInterest and a Property of that feature.

has subsystem
type: ObjectProperty
sub property of: hasPart
comment: Haspart relation between a system and its parts.

has survival property
type: ObjectProperty
sub property of: has property
comment: Relation from a SurvivalRange to a Property describing the survial range of a system. For example, to the temperature extreme that a system can withstand before being considered damaged.

has survival range
type: ObjectProperty
sub property of: has property
comment: A Relation from a System to a SurvivalRange.

has value
type: ObjectProperty
sub property of: hasRegion

implemented by
type: ObjectProperty
sub property of: describes
inverse of: implements
comment: A relation between the description of an algorithm, procedure or method and an entity that implements that method in some executable way. For example, between a scientific measuring method and a sensor the senses via that method.

implements
type: ObjectProperty
sub property of: isDescribedBy
comment: A relation between an entity that implements a method in some executable way and the description of an algorithm, procedure or method. For example, between a Sensor and the scientific measuring method that the Sensor uses to observe a Property.

in condition
type: ObjectProperty
comment: Describes the prevailing environmental conditions for MeasurementCapabilites, OperatingConditions and SurvivalRanges. Used for example to say that a sensor has a particular accuracy in particular conditions. (see also MeasurementCapability)

in deployment
type: ObjectProperty
sub property of: isParticipantIn
comment: Relation between a Platform and a Deployment, recording that the object was used as a platform for a system/sensor for a particular deployment: as in this PhysicalObject is acting as a Platform inDeployment Deployment.

is produced by
type: ObjectProperty
comment: Relation between a producer and a produced entity: for example, between a sensor and the produced output.

is property of
type: ObjectProperty
sub property of: isQualityOf
comment: Relation between a FeatureOfInterest and a Property (a Quality observable by a sensor) of that feature.

isProxyFor
type: ObjectProperty
comment: A relation from a Stimulus to the Property that the Stimulus is serving as a proxy for. For example, the expansion of the quicksilver is a stimulus that serves as a proxy for temperature, or an increase or decrease in the spinning of cups on a wind sensor is serving as a proxy for wind speed.

made observation
type: ObjectProperty
sub property of: isObjectIncludedIn
inverse of: observedBy
comment: Relation between a Sensor and Observations it has made.

observation result
type: ObjectProperty
sub property of: isSettingFor
source: skos:closeMatch 'result' [O&M - ISO/DIS 19156] http://portal.opengeospatial.org/files/?artifact_id=41579
comment: Relation linking an Observation (i.e., a description of the context, the Situation, in which the observatioin was made) and a Result, which contains a value representing the value associated with the observed Property.

observation result time
type: ObjectProperty
sub property of: hasRegion
source: http://www.opengeospatial.org/standards/om
comment: The result time is the time when the procedure associated with the observation act was applied.
comment: 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]

observation sampling time
type: ObjectProperty
sub property of: hasRegion
source: http://www.opengeospatial.org/standards/om
comment: 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.
comment: 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.

observed property
type: ObjectProperty
sub property of: isSettingFor
source: skos:exactMatch 'observedProperty' [O&M - ISO/DIS 19156] http://portal.opengeospatial.org/files/?artifact_id=41579
comment: Relation linking an Observation to the Property that was observed. The observedProperty should be a Property (hasProperty) of the FeatureOfInterest (linked by featureOfInterest) of this observation.

observes
type: ObjectProperty
property chain axiom: has measurement capability
property chain axiom: for property
property chain axiom: made observation
property chain axiom: observed property
comment: Relation between a Sensor and a Property that the sensor can observe. Note that, given the DUL modelling of Qualities, a sensor defined with 'observes only Windspeed' technically links the sensor to particular instances of Windspeed, not to the concept itself - OWL can't express concept-concept relations, only individual-individual. The property composition ensures that if an observation is made of a particular quality then one can infer that the sensor observes that quality.

of feature
type: ObjectProperty
comment: A relation between some aspect of a sensing entity and a feature. For example, from a sensor to the features it can observe properties of, or from a deployment to the features it was installed to observe. Also from a measurement capability to the feature the capability is described for. (Used in conjunction with forProperty).

on platform
type: ObjectProperty
sub property of: hasLocation
comment: Relation between a System (e.g., a Sensor) and a Platform. The relation locates the sensor relative to other described entities entities: i.e., the Sensor s1's location is Platform p1. More precise locations for sensors in space (relative to other entities, where attached to another entity, or in 3D space) are made using DOLCE's Regions (SpaceRegion).

quality of observation
type: ObjectProperty
sub property of: has property
source: skos:exactMatch 'resultQuality' [O&M - ISO/DIS 19156] http://portal.opengeospatial.org/files/?artifact_id=41579
comment: Relation linking an Observation to the adjudged quality of the result. This is of course complimentary to the MeasurementCapability information recorded for the Sensor that made the Observation.

sensing method used
type: ObjectProperty
sub property of: satisfies
source: http://www.bipm.org/en/committees/jc/jcgm/wg2.html
comment: 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]

start time
type: ObjectProperty
sub property of: hasRegion

Accuracy
type: Class
subclass of: Measurement Property
source: skos:exactMatch 'measurement accuracy/accuracy' [VIM 2.13] http://www.bipm.org/utils/common/documents/jcgm/JCGM_200_2008.pdf
comment: The closeness of agreement between the value of an observation and the true value of the observed quality.

Battery Lifetime
type: Class
subclass of: Survival Property
comment: Total useful life of a battery.

Condition
type: Class
subclass of: Property
comment: Used to specify ranges for qualities that act as conditions on a system/sensor's operation. For example, wind speed of 10-60m/s is expressed as a condition linking a quality, wind speed, a unit of measurement, metres per second, and a set of values, 10-60, and may be used as the condition on a MeasurementProperty, for example, to state that a sensor has a particular accuracy in that condition.

Deployment
type: Class
subclass of: Deployment-related Process
subclass of: Restriction
  on property: deployed on platform
  all values from: Platform
subclass of: Restriction
  on property: deployed system
  all values from: System
source: skos:closeMatch 'Deployment' [MMI Dev] http://marinemetadata.org/community/teams/ontdevices
comment: The ongoing Process of Entities (for the purposes of this ontology, mainly sensors) deployed for a particular purpose. For example, a particular Sensor deployed on a Platform, or a whole network of Sensors deployed for an observation campaign. The deployment may have sub processes, such as installation, maintenance, addition, and decomissioning and removal.

Deployment-related Process
type: Class
subclass of: Process
subclass of: Restriction
  on property: deployment process part
  all values from: Deployment-related Process
source: http://www.w3.org/2005/Incubator/ssn/
comment: Place to group all the various Processes related to Deployment. For example, as well as Deplyment, installation, maintenance, deployment of further sensors and the like would all be classified under DeploymentRelatedProcess.

detection limit
type: Class
subclass of: Measurement Property
source: skos:exactMatch 'detection limit' [VIM 4.18] http://www.bipm.org/utils/common/documents/jcgm/JCGM_200_2008.pdf
comment: An observed value for which the probability of falsely claiming the absence of a component in a material is Î², given a probability Î± of falsely claiming its presence.

Device
type: Class
subclass of: System
subclass of: DesignedArtifact
source: http://www.w3.org/2005/Incubator/ssn/
comment: 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).

Drift
type: Class
subclass of: Measurement Property
source: skos:exactMatch 'instrumental drift' [VIM 4.21] http://www.bipm.org/utils/common/documents/jcgm/JCGM_200_2008.pdf
comment: A, continuous or incremental, change in the reported values of observations over time for an unchanging quality.

Feature of Interest
type: Class
subclass of: Thing
subclass of: Class
  union of: Event
  union of: Object
subclass of: Restriction
  on property: has property
  some values from: Property
subclass of: Restriction
  on property: has property
  all values from: Property
source: skos:exactMatch 'feature' [O&M] http://www.opengeospatial.org/standards/om
comment: A feature is an abstraction of real world phenomena (thing, person, event, etc).

Frequency
type: Class
subclass of: Measurement Property
comment: The smallest possible time between one observation and the next.

Input
type: Class
disjoint with: Output
source: http://marinemetadata.org/community/teams/ontdevices
comment: Any information that is provided to a process for its use [MMI OntDev]

Latency
type: Class
subclass of: Measurement Property
comment: The time between a request for an observation and the sensor providing a result.

Maintenance Schedule
type: Class
subclass of: Operating Property
comment: Schedule of maintenance for a system/sensor in the specified conditions.

Measurement Capability
type: Class
subclass of: Property
subclass of: Restriction
  on property: for property
  all values from: Property
subclass of: Restriction
  on property: has measurement property
  all values from: Measurement Property
subclass of: Restriction
  on property: in condition
  all values from: Condition
source: Similar idea to MeasurementCapability in MMI Device Ontology http://marinemetadata.org/community/teams/ontdevices But the the two express the relationship between constraints and multiple measurement properties differently. The conditions linked to a MeasurementCapability are skos:exactMatch to 'influence quantity' [VIM 2.52] http://www.bipm.org/utils/common/documents/jcgm/JCGM_200_2008.pdf
comment: Collects together measurement properties (accuracy, range, precision, etc) and the environmental conditions in which those properties hold, representing a specification of a sensor's capability in those conditions. The conditions specified here are those that affect the measurement properties, while those in OperatingRange represent the sensor's standard operating conditions, including conditions that don't affect the observations.

Measurement Property
type: Class
subclass of: Property
comment: An identifiable and observable characteristic of a sensor's observations or ability to make observations.

Measurement Range
type: Class
subclass of: Measurement Property
source: skos:exactMatch 'measuring interval/measurement range' [VIM 4.7] http://www.bipm.org/utils/common/documents/jcgm/JCGM_200_2008.pdf
comment: The set of values that the sensor can return as the result of an observation under the defined conditions with the defined measurement properties. (If no conditions are specified or the conditions do not specify a range for the observed qualities, the measurement range is to be taken as the condition for the observed qualities.)

Observation
type: Class
subclass of: Situation
subclass of: Restriction
  on property: includesEvent
  some values from: Stimulus
subclass of: Restriction
  on property: feature of interest
  all values from: Feature of Interest
subclass of: Restriction
  on property: observation result
  all values from: Sensor Output
subclass of: Restriction
  on property: observedBy
  all values from: Sensor
subclass of: Restriction
  on property: observed property
  all values from: Property
subclass of: Restriction
  on property: sensing method used
  all values from: Sensing
subclass of: Restriction
  on property: observation result time
  min cardinality: 0
subclass of: Restriction
  on property: observation sampling time
  min cardinality: 0
subclass of: Restriction
  on property: quality of observation
  min cardinality: 0
subclass of: Restriction
  on property: feature of interest
  qualified cardinality: 1
  on class: Feature of Interest
subclass of: Restriction
  on property: observedBy
  qualified cardinality: 1
  on class: Sensor
subclass of: Restriction
  on property: observed property
  qualified cardinality: 1
  on class: Property
subclass of: Restriction
  on property: sensing method used
  qualified cardinality: 1
  on class: Sensing
source: skos:closeMatch 'observation' [O&M] http://www.opengeospatial.org/standards/om Observation in this ontology and O&M are described differently (O&M records an observation as an act/event), but they record the same thing and are essentially interchangeable. The difference is in the ontological structure of the two, not the data or use. Observation here records a Situation (the estimation of the value of a Property) and a description of the method that was used (along with the participants), while O&M interprets an Observation as the event itself; there must, however, have been an event that lead to our situation, so both are records of events. The distinction is between the event itself and the record of what happened in that event. skos:closeMatch 'measurement result' [VIM 2.9] http://www.bipm.org/utils/common/documents/jcgm/JCGM_200_2008.pdf Measurement result in VIM is the measured value plus any other relevant information, which means that measurement result and observation will often be associated to the same data (a value, a time, a property, etc.).
comment: An Observation is a Situation in which a Sensing method has been used to estimate or calculate a value of a Property of a FeatureOfInterest. Links to Sensing and Sensor describe what made the Observation and how; links to Property and Feature detail what was sensed; the result is the output of a Sensor; other metadata details times etc.

Observation Value
type: Class
subclass of: Region
subclass of: Restriction
  on property: isRegionFor
  some values from: Sensor Output
source: skos:exactMatch 'measured quantity value' [VIM 2.10] http://www.bipm.org/utils/common/documents/jcgm/JCGM_200_2008.pdf skos:exactMatch 'observed value' [SensorML OGC-0700] http://www.opengeospatial.org/standards/sensorml skos:closeMatch 'observation result' [O&M] http://www.opengeospatial.org/standards/om O&M conflates what we have as SensorOutput and ObservationValue into observation result, though the OGC standard does say "result contains a value" and "a result which has a value", which fits naturally with the model here.
comment: The value of the result of an Observation. An Observation has a result which is the output of some sensor, the result is an information object that encodes some value for a Feature.

Operating Power Range
type: Class
subclass of: Operating Property
comment: Power range in which system/sensor is expected to operate.

Operating Property
type: Class
subclass of: Property
comment: An identifiable characteristic of the environmental and other conditions in which the sensor is intended to operate. May include power ranges, power sources, standard configurations, attachments and the like.

Operating Range
type: Class
subclass of: Property
subclass of: Restriction
  on property: has operating property
  all values from: Operating Property
subclass of: Restriction
  on property: in condition
  all values from: Condition
source: skos:broaderMatch 'reference operating condition' [VIM 4.11] http://www.bipm.org/utils/common/documents/jcgm/JCGM_200_2008.pdf The difference is that here we also allow for qualities that aren't VIM influence quantities [VIM 2.52] - for example, a quantity that alters the power requirements, but doesn't affect the measurement properties - conditions specified in MeasurementCapability should be influence quantities.
comment: The environmental conditions and characteristics of a system/sensor's normal operating environment. Can be used to specify for example the standard environmental conditions in which the sensor is expected to operate (a Condition with no OperatingProperty), or how the environmental and other operating properties relate: i.e., that the maintenance schedule or power requirements differ according to the conditions.

Output
type: Class
source: http://marinemetadata.org/community/teams/ontdevices
comment: Any information that is reported from a process. [MMI OntDev]

Platform
type: Class
subclass of: PhysicalObject
subclass of: Restriction
  on property: attached system
  all values from: System
subclass of: Restriction
  on property: in deployment
  all values from: Deployment
source: skos:exactMatch 'platform' [SensorML OGC-0700] http://www.opengeospatial.org/standards/sensorml
comment: An Entity to which other Entities can be attached - particuarly Sensors and other Platforms. For example, a post might act as the Platform, a bouy might act as a Platform, or a fish might act as a Platform for an attached sensor.

Precision
type: Class
subclass of: Measurement Property
source: skos:exactMatch 'measurement precision/precision' [VIM 2.15] http://www.bipm.org/utils/common/documents/jcgm/JCGM_200_2008.pdf
comment: The closeness of agreement between replicate observations on an unchanged or similar quality value: i.e., a measure of a sensor's ability to consitently reproduce an observation.

Process
type: Class
subclass of: Method
subclass of: Restriction
  on property: has output
  some values from: Output
subclass of: Restriction
  on property: has input
  all values from: Input
subclass of: Restriction
  on property: has output
  all values from: Output
source: http://www.w3.org/2005/Incubator/ssn/
comment: 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]

Property
type: Class
subclass of: Quality
subclass of: Restriction
  on property: is property of
  some values from: Feature of Interest
source: skos:exactMatch 'property' [O&M] http://www.opengeospatial.org/standards/om
comment: An observable Quality of an Event or Object. That is, not a quality of an abstract entity as is also allowed by DUL's Quality, but rather an aspect of an entity that is intrinsic to and cannot exist without the entity and is observable by a sensor.

Resolution
type: Class
subclass of: Measurement Property
source: skos:exactMatch 'resolution' [VIM 4.14] http://www.bipm.org/utils/common/documents/jcgm/JCGM_200_2008.pdf
comment: The smallest difference in the value of a quality being observed that would result in perceptably different values of observation results.

Response time
type: Class
subclass of: Measurement Property
source: skos:exactMatch 'step response time' [VIM 4.23] http://www.bipm.org/utils/common/documents/jcgm/JCGM_200_2008.pdf
comment: The time between a (step) change inthe value of an observed quality and a sensor (possibly with specified error) 'settling' on an observed value.

Selectivity
type: Class
subclass of: Measurement Property
source: skos:exactMatch 'selectivity' [VIM 4.13] http://www.bipm.org/utils/common/documents/jcgm/JCGM_200_2008.pdf
comment: Selectivity is a property of a sensor whereby it provides observed values for one or more qualities such that the values of each quality are independent of other qualities in the phenomenon, body, or substance being investigated.

Sensing
type: Class
subclass of: Process
source: http://www.w3.org/2005/Incubator/ssn/
comment: Sensing is a process that results in the estimation, or calculation, of the value of a phenomenon.

Sensing Device
type: Class
subclass of: Device
subclass of: Sensor
source: http://www.w3.org/2005/Incubator/ssn/
comment: A sensing device is a device that implements sensing.

Sensitivity
type: Class
subclass of: Measurement Property
source: skos:exactMatch 'sensitivity' [VIM 4.12] http://www.bipm.org/utils/common/documents/jcgm/JCGM_200_2008.pdf
comment: Sensitivity is the quotient of the change in a result of sensor and the corresponding change in a value of a quality being observed.

Sensor
type: Class
subclass of: PhysicalObject
subclass of: Restriction
  on property: implements
  some values from: Sensing
subclass of: Restriction
  on property: detects
  all values from: Stimulus
subclass of: Restriction
  on property: has measurement capability
  all values from: Measurement Capability
subclass of: Restriction
  on property: observes
  all values from: Property
source: skos:exactMatch 'sensor' [SensorML OGC-0700] http://www.opengeospatial.org/standards/sensorml skos:closeMatch 'observation procedure' [O&M] http://www.opengeospatial.org/standards/om O&M allows sensors, methods, instruments, systems, algorithms and process chains as the processUsed of an observation; this ontology allows a similar range of things (any thing that can do sensing), just they are all grouped under the term sensor (which is thus wider than the O&M concept).
comment: A sensor can do (implements) sensing: that is, a sensor is any entity that can follow a sensing method and thus observe some Property of a FeatureOfInterest. Sensors may be physical devices, computational methods, a laboratory setup with a person following a method, or any other thing that can follow a Sensing Method to observe a Property.

Sensor Data Sheet
type: Class
subclass of: InformationObject
source: http://www.w3.org/2005/Incubator/ssn/
comment: A data sheet records properties of a sensor. A data sheet might describe for example the accuracy in various conditions, the power use, the types of connectors that the sensor has, etc. Generally a sensor's properties are recorded directly (with hasMeasurementCapability, for example), but the data sheet can be used for example to record the manufacturers specifications verses observed capabilites, or if more is known than the manufacturer specifies, etc. The data sheet is an information object about the sensor's properties, rather than a direct link to the actual properties themselves.

Sensor Input
type: Class
equivalent class: Stimulus
subclass of: Event
subclass of: Restriction
  on property: isProxyFor
  all values from: Property
source: http://www.w3.org/2005/Incubator/ssn/
comment: An Event in the real world that 'triggers' the sensor. The properties associated to the stimulus may be different to eventual observed property. It is the event, not the object that triggers the sensor.

Sensor Output
type: Class
subclass of: InformationObject
subclass of: Restriction
  on property: has value
  some values from: Observation Value
subclass of: Restriction
  on property: is produced by
  some values from: Sensor
source: http://www.w3.org/2005/Incubator/ssn/ skos:closeMatch 'observation result' [O&M] http://www.opengeospatial.org/standards/om See comments at ObservationValue.
comment: A sensor outputs a piece of information (an observed value), the value itself being represented by an ObservationValue.

Stimulus
type: Class
subclass of: Event
source: http://www.w3.org/2005/Incubator/ssn/
comment: An Event in the real world that 'triggers' the sensor. The properties associated to the stimulus may be different to eventual observed property. It is the event, not the object that triggers the sensor.

Survival Property
type: Class
subclass of: Property
comment: An identifiable characteristic that represents the extent of the sensors useful life. Might include for example total battery life or number of recharges, or, for sensors that are used only a fixed number of times, the number of observations that can be made before the sensing capability is depleted.

Survival Range
type: Class
subclass of: Property
subclass of: Restriction
  on property: has survival property
  all values from: Survival Property
subclass of: Restriction
  on property: in condition
  all values from: Condition
source: skos:narrowerMatch 'limiting operating condition' [VIM 4.10] http://www.bipm.org/utils/common/documents/jcgm/JCGM_200_2008.pdf
comment: The conditions a sensor can be exposed to without damage: i.e., the sensor continues to operate as defined using MeasurementCapability. If, however, the SurvivalRange is exceeded, the sensor is 'damaged' and MeasurementCapability specifications may no longer hold.

System
type: Class
subclass of: PhysicalObject
subclass of: Restriction
  on property: has subsystem
  some values from: System
subclass of: Restriction
  on property: has deployment
  all values from: Deployment
subclass of: Restriction
  on property: has operating range
  all values from: Operating Range
subclass of: Restriction
  on property: has subsystem
  all values from: System
subclass of: Restriction
  on property: has survival range
  all values from: Survival Range
subclass of: Restriction
  on property: on platform
  all values from: Platform
source: http://www.w3.org/2005/Incubator/ssn/
comment: 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.

System Lifetime
type: Class
subclass of: Survival Property
comment: Total useful life of a sensor/system (expressed as total life since manufacture, time in use, number of operations, etc.).