SYMBOL STRING CONVERSION METHOD, VOICE RECOGNITION METHOD USING THE SAME, DEVICE OF SYMBOL STRING CONVERSION AND VOICE RECOGNITION AND PROGRAM, AND RECORDING MEDIUM FOR THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a symbol string conversion method that makes a hypothesis generation rule incapable of a cascade connection dependable.SOLUTION: The symbol string conversion method is configured to include: an auxiliary hypothesis generation step in which an input signal selection unit selects any one of an input symbol string to be input to a hypothesis generation unit of a previous stage with reference to an input/output symbol string arrangement storage unit and an output signal string to be output by each hypothesis generation unit of the previous stage and a stage before the previous stage as an input symbol string of a hypothesis generation unit of an m-th stage (m is an integer of 1 to M), and the hypothesis generation unit of the m-th stage repeats an auxiliary hypothesis generation step where the hypothesis generation unit of the m-th stage generates an auxiliary hypothesis fto an M-th stage while incrementing m; a hypothesis correction step in which a hypothesis correction unit corrects a weight of an auxiliary hypothesis fof the previous stage by an accumulation weight of the auxiliary hypothesis f, and repeats the correction until an accumulation weight of a hypothesis fis corrected by an accumulation weight of the auxiliary hypothesis while decrementing m; and a hypothesis narrowing-down step in which a hypothesis narrowing-down unit extracts a hypothesis which a corrected accumulation weight points to a specific value or an auxiliary hypothesis thereof, and narrows down the extracted hypothesis or auxiliary hypothesis as an input symbol string of the hypothesis narrowing-down unit of a next stage.