Patent ID: 7359842
Filing Date: 2008-04-15
Classification: G06K

Abstract:
1. A soft sensor, comprising: a case base to store a plurality of cases in an input space which is quantized into a plurality of unit input spaces, each case including history data in a corresponding unit input space, the history data being constituted by input data and associated output data obtained in advance from a physical target, the input space being quantized such that the output data associated with the input data in each unit input space satisfies a desired output allowable error, the case base being adaptable in real time to a new data set including new input data and associated new output data received from the physical target to update the cases stored in the case base; a case retrieving section which acquires, by searching said case base, a retrieved case from one of the unit input spaces having at least one of the cases, the one of the unit spaces being located at a minimum topological distance from a new unit input space corresponding to a new set of input data; an output estimating section which calculates new output data corresponding to the new set of input data from the retrieved case and outputs an output estimation of a physical output quantity of the physical target; an output evaluating section which calculates an estimation error contained in the output estimation output from said output estimating section on the basis of the output allowable error and a topological distance between the new unit input space corresponding to the new set of input data and the unit input space of the retrieved case, and outputs the estimation error corresponding to the output estimation; and a function evaluating section which, when the new set of input data corresponds to the unit input space having no case, uses the output estimation obtained from said output estimating section in correspondence with the new set of input data and, a true output value obtained from the physical target, and the estimation error corresponding to the output estimation to evaluate whether said soft sensor is properly functioning.