Patterns and Conventions for Defining OBOE-Compatible Ontologies

…

Based on OBOE 1.0, June, 2010

Table of Contents

1. Basic OBOE structure

2. Basic Conventions

3. Entities and Characteristics

4. Measurement standards and units

5. Measurement types

6. Context relationships

7. More patterns

8. Imports

1. Basic OBOE structure (oboe-core)

Entity

Characteristic

Observation

Measurement

Protocol Standard

measurementFor

hasMeasurement

+ hasPrecision : decimal+ hasMethod : anyType

ofCharacteristic

usesProtocol usesStandard

ofEntityhasContext

1..1

*

1..1

*

*

*

1..1 1..1

1..1

**

hasValue

1..1

*

*

standardForprotocolFor

valueFor

observedBy

contextFor

measuredBy

Note: Add ObservationCollection

1. OBOE Basic Structure (oboe-core)

• State the basics here …

2. Basic Conventions

Conventions used by core oboe ontologies (suggested for compatible ontologies)

– Class names are capitalized (e.g., Plant, Height)

– Terms in names are capitalized (e.g., CarbonContent)

– Classes have comments (using rdfs:comment)

– Ontologies have a single rdfs:label (e.g., “oboe-units”)

– Ontologies have a comment (using rdfs:comment)

2. Basic Conventions

When naming entities, characteristics, and standards it is suggested they make sense in the following sentences …

– The <characteristic> of an <entity> was recorded using the <standard> and the <protocol>

– The <entity> was recorded <characteristic> the <entity>

– For example: …

3. Entities and Characteristics

Entities represent distinct physical or conceptual objects

– Examples include trees, plants, air, water, soil

– Entities are organized into entity classes

– A class denotes a set of entities (that conform to the class)

Each observation has …

– An observed entity

Together with zero or more …

– Measurements of the entity; and

– Contexts represented through other observations

3. Entities and Characteristics

Characteristics represent properties of entities

– Examples include height, mass, speed, volume, etc.

– Characteristics are also organized into classes

– A characteristic is a particular occurrence of the property

– For instance, a particular occurrence of the height characteristic (tied to some entity)

– Each characteristic of an entity has a value

A measurement asserts a value for a characteristic

– A recorded value of the characteristic for the observed entity

3. Entities and Characteristics

Entities vs. characteristics

– Characteristics are dependent on entities …

– They must be combined with an entity (the object possessing the characteristic)

– They always have a value

Depending on the type of characteristic …

– The value can be of a primitive (like a string or numeric value)

– Or another entity (e.g., tree1 nextTo tree2, hawk1 ate vole1)

3. Entities and Characteristics

Special types of entities

– Primitive values are reserved for denoting basic values

– Currently strings, decimals (numeric values), and Booleans

3. Entities and Characteristics

Types of characteristics

PhysicalCharacteristic– Any characteristic that is “physically” manifested

Qualifier– A term used to modify the meaning of a physical

characteristic, without changing its measurement standard

– Examples include aggregates such as average, minimum, etc.

Name– The globally or locally unique name assigned to the entity

– For example, Plot “A”, Tree id “555”, Site “1”

Type– A characteristic asserting the entity class the entity is a

member of

4. Measurement standards and units

Measurement standards

– Represent nominal, ordinal, interval, and ratio scales

– Units are a special type of standard (ratio scales)

– Indexes are another special type of standard (e.g., pH)

4. Measurement standards and units

Units are divided into three subclasses

BaseUnit– Fundamental units, that is, not composed of other

units (through products of powers of other units)

– The 7 SI fundamental units are examples of base units

DerivedUnit– A base unit raised to a power

CompositeUnit– The product of 2 or more base or derived units

4. Measurement standards and units

Units are divided into three subclasses

MeasurementStandard

Unit

BaseUnit

DerivedUnit

CompositeUnit

+ hasPower = int

hasUnit1..1

*

U

hasUnit

*

4. Measurement standards and units

Standards (including units) typically restrict the characteristics of measurements

MeasurementStandard

Unit

BaseUnit

DerivedUnit

CompositeUnit

+ hasPower = int

hasUnit1..1

*

U

hasUnit

*

CharacteristicMeasurementstandardFor ► ofCharacteristic ►

For example (in Manchester OWL syntax):

Meter subClassOf BaseUnit and standardFor only (Measurement and ofCharacteristic only Length)

4. Measurement standards and units

The oboe-units ontology

• Defines many common units and characteristics

• Drawn from LTER unit database (among other sources)

• Also includes some indexes

• Includes tricky examples such as Acre

• Defines unit conversions (via the UnitConversion class)

– Source unit to target unit

– With offset and multiplier values

5. Measurement types

A measurement type …

• …