]> OBOE '$Id: Observation.owl,v 1.29 2008/01/30 04:36:12 bowers Exp $' This property relates a characteristic to the entity it is a characteristic of. A characteristic is of exactly one entity. This property gives the characteristic that a characteristic value is of. A characteristic value can be the value of many characteristics. This property relates measurement standards to the characteristics they are standards for. This property gives the base dimension of a simple derived dimension. This property gives the base unit of a simple derived unit. This property relates an entity to one of its characteristics. This property gives the value of an entity's characteristic. Characteristics have exactly one value. This property states that one observation serves as the context for another observation. Context defines a semantic relationship between two entities that is a fundamental aspect of the observations, but not necessarily of the entities themselves. For example, most measurements are accomplished in a spatio-temporal framework that might be valuable context. The assertions made by contextual observations are assumed of the contextualized observations. Context is a transitive relationship. This property connects a context object to an observation, where the entity of the observation is serving as context for some other observed entity. This property relates a context object to its associated relationship object. This property relates a complex derived dimension to one of its component dimensions. This property connects an entity to a relationship object, where the entity plays the role of the source of the relationship. This property represents an ordering (precedence) relationship between two characteristic values. The higher rank property induces a strict (irreflexive, asymmetric) partial ordering over a given set of characteristic values. This property gives the measurements of the observed entity. This property connects an observation to a context object, where the entity of the observation is being contextualized. This property connects a relationship object to an entity, where the entity plays the role of the target of the relationship. This property gives the source base unit of a unit conoboe. The source unit is the unit being mapped from. This property gives the standard values of a measurement standard. This property gives the target base unit of a unit conoboe. The target unit is the unit being mapped to. This property relates a complex derived unit with one of its component units. This property gives the entity characteristic measured by the measurement. This property gives the observed entity of an observation. This property gives the standard (e.g., unit) used in a measurement. This property gives the code for a standard value. This property gives the multiplier value of a unit conoboe. For example, to convert from celsius to fahrenheit we multiply by the multiplier 9/5 and add 32. This property gives the offset value of a unit conoboe. For example, to convert from celsius to fahrenheit we multiply by 9/5 and add the offset 32. This propert gives the integer value that (base and simple) dimensions and units are raised to. This property gives the precision of a measurement value. This property gives the value of the measurement. Base Dimension 1 A base dimension represents a base physical quantity, e.g., the SI base dimensions are length, mass, time, electric current, thermodynamic temperature, amount of substance, and luminous intensity. Base Unit 1 A base unit represents an atomic unit from which other more complex units can be built. Characteristic A characteristic represents a property of an entity that can be measured (e.g., height, length, or color). We adopt the distinction between things and properties of M. Bunge (1979). Namely, objects (entities) possess properties (characteristics), there are no objects without properties, and properties are attached to objects. When a characteristic is observed, it is measured, and a characteristic is the necessary focus of a measurement (i.e., a characteristic is a property of an entity being attributed a value by a measurement). Each characteristic is associated to exactly one entity. Characteristic Value A characteristic value represents a possible value for an entity characteristic. Complex Derived Dimension 2 A complex derived dimension is a derived physical quantity that consists of two or more base or simple physical quantities (dimensions). Each component dimension is "multiplied" together to form the derived dimension. For example, a complex derived dimension representing acceleration (length*time^-2) consists of the base dimension length and the simple derived dimension per time squared (time^-2). Complex Derived Unit 2 A complex derived unit is a unit that consists of two or more base or simple derived units. Each component unit is "multiplied" together to form the derived unit. For example, a complex derived unit representing 'meter per second squared' (m*s^-2) consists of the base unit 'meter' (m) and the simple derived unit 'per second squared' (s^-2). Context A context represents an asserted relationship between two observed entities at the time of observation. The relationship is directional in that one of the observed entities serves the role as context for the other. Date-Time Measurement Standard A date-time represents date and time values (e.g., 14:00, 2006-07-23). Dimension A dimension characteristic represents a physical quantity (both intensive and extensive) of an entity (e.g., length, weight, area, etc.) Entity An entity denotes a concrete or conceptual object that has been observed (e.g., a tree, a community, an ecological process). We adopt the distinction between objects and properties of M. Bunge (1979). Namely, objects (entities) possess properties (characteristics), there are no objects without properties, and properties are attached to objects. Entities constitute the foci of observations, i.e., every observation is of some entity. Entity Classification A classification characteristic is a directly measurable or recorded property (e.g., height, color, weight) of an entity. Entity Classification Qualifier An Entity Classification Qualifier denotes a generic derived (e.g., computed) property of an entity. These characteristics must be combined with classification characteristics (through intersection) to be used for measurement. For example, the qualifier Minimum can be combined with a (dimension) characteristic Length to create a measurable Minimum Length characteristic. Entity Name A name characteristic provides the name used for identifying (either globally or within a context) an entity. Entity Type A type characteristic provides the type (or class) of an entity as a value. Interval-Ratio Measurement Standard An interval-ratio standard is an ordinal standard that further supports interval and ratio measurements. In an interval standard, equal differences between measurement values represent equivalent intervals in which differences between arbitrary pairs of measurements can be meaningfully compared. In a ratio standard, values additionally have meaningful ratios between arbitrary pairs. Measurement A measurement is an assertion that a characteristic of an entity was measured and/or recorded. A measurement is also composed of a value, a measurement standard, and a precision (associated with the measured value). Measurements also encapsulate characteristics that were recorded, but not necessarily measured in a physical sense. For example, the name of a location and a taxon can be captured through measurements. Measurement Standard A measurement standard defines a reference for comparing (or naming) entities. A measurement standard can be defined intentionally (e.g., as in the case of units) or extensionally (by listing the values of the standard, e.g., for color this might be red, blue, yellow, etc). Nominal Measurement Standard A nominal standard is a measurement standard in which names are assigned to entities as labels. Numeric-Index Measurement Standard A numeric index is typically defined by a mathematical equation, e.g., Shannon diversity, pH, and Richter scale are each numeric indices. Numeric indices typically go with characteristic qualifiers, e.g., the ratio of average height from two populations. Observation An observation is an assertion that an entity was observed. An observation may consist of measurements that refer to one or more measured characteristics of the entity. Observations are made within a context. The context of an observation is given by other observations, e.g., an observation of a particular location may serve as context for an observation of an organism. Ordered Characteristic Value An ordered value is a characteristic value that is related to other characteristic values through a precedence (order) relation. Order is specified using the 'hasHigherRank' property. Ordinal Measurement Standard An ordinal standard is a nominal standard in which values represent a rank order (1st, 2nd, 3rd, etc.) of the entities measured. Relationship A relationship object represents a directed relationship between a source and target entity. Simple Derived Dimension 1 0 A simple derived dimension represents a base physical quantity raised to a power (other than 0 or 1). For example, area is a simple derived dimension representing the base dimension length raised to the power 2. Simple Derived Unit 1 0 A simple derived unit is a unit that raises a base unit to an integer power (other than 0 or 1). Standard Characteristic Value A standard value is a specially designated characteristic value that is typically associated with a particular measurement standard. All standard values have value codes that are used to denote the corresponding value within a measurement. Unit The base class for physical measurement units. Unit Conversion A unit conversion defines a mapping from a source unit to a target unit.