;;; -*- Mode:Lisp; Syntax: Common-lisp; Package:ONTOLINGUA-USER; Syntax:COMMON-LISP; Base:10 -*-;;; Standard Units and Dimensions;;; (c) 1993 Greg Olsen and Thomas Gruber(in-package "ONTOLINGUA-USER") (define-theorystandard-dimensions(physical-quantities) "This theory defines a set of physical dimensions for quantities. It is independent of any choice of units of measure. This set is based on physics and economics." :issues ("(c) 1993, 1994 Greg R. Olsen, Thomas R. Gruber, and Yves Peligry" "This theory used to be combined with standard-dimensions in a theory called standard-units-and-dimensions. We divided them because commitments to one are often independent of commitments to the other." (:see-also "The EngMath paper on line"))) (in-theory 'standard-dimensions);; The IDENTITY-DIMENSION is defined in the base theory, PHYSICAL-QUANTITIES.(define-instanceLENGTH-DIMENSION(physical-dimension) "The fundamental dimension of length, as defined by the SI standard.") (define-instanceMASS-DIMENSION(physical-dimension) "The fundamental dimension of mass, as defined by the SI standard.") (define-instanceTIME-DIMENSION(physical-dimension) "The fundamental dimension of physical, continuous time, as defined by the SI standard.") (define-instanceELECTRICAL-CURRENT-DIMENSION(physical-dimension) "The fundamental dimension of electrical current, as defined by the SI standard.") (define-instanceTHERMODYNAMIC-TEMPERATURE-DIMENSION(physical-dimension) "The fundamental dimension of temperature, as defined by the SI standard.") (define-instanceAMOUNT-OF-SUBSTANCE-DIMENSION(physical-dimension) "The fundamental dimension of amount of substance, as defined by the SI standard.") (define-instanceLUMINOUS-INTENSITY-DIMENSION(physical-dimension) "The fundamental dimension of luminous-intensity, as defined by the SI standard.") (define-instanceFORCE-DIMENSION(physical-dimension) "The physical dimension of force is defined as mass times length over time squared. In some systems FORCE-DIMENSION is fundamental and MASS-DIMENSION is a derived dimension. This theory goes with the SI standard, but we include the definition of force as a non-fundamental built-in dimension." :axiom-def (= FORCE-DIMENSION (* MASS-DIMENSION (* LENGTH-DIMENSION (expt TIME-DIMENSION -2))))) (define-instanceENERGY-DIMENSION(physical-dimension) "The physical dimension of energy is defined as mass times length squared over time squared." :axiom-def (= ENERGY-DIMENSION (* MASS-DIMENSION (* (expt LENGTH-DIMENSION 2) (expt TIME-DIMENSION -2))))) (define-instanceCURRENCY-DIMENSION(physical-dimension) "The fundamental dimension of currency or money. CURRENCY-DIMENSION is to currencies as US-dollar's and ECU's as the LENGTH-DIMENSION is to units of length such as meters.") (define-instancearea-dimension(physical-dimension) "The physical dimension of an area is defined as length dimension squared." :axiom-def (= area-dimension (expt length-dimension 2)) :issues ("Provided by Bernd Bachmann, DFKI")) (define-instancepressure-dimension(physical-dimension) "the physical dimension of pressure is defined as force over area" :axiom-def (= pressure-dimension (* force-dimension (expt area-dimension -1))) :issues ("Provided by Bernd Bachmann, DFKI")) (define-instance therm^-1-dimension (physical-dimension) :axiom-def (= therm^-1-dimension (expt thermodynamic-temperature-dimension -1)) :issues ("Provided by Bernd Bachmann, DFKI")) (define-instancework-dimension(physical-dimension) :axiom-def (= work-dimension (* force-dimension length-dimension)) :issues ("Provided by Bernd Bachmann, DFKI"))