Speech recognition system with maximum entropy language models

A method of setting a free orthogonalized parameter

• 88 λ α ortho ps of an attribute α in a maximum-entropy speech model MESM, if this free parameter could not be set with the help of a training algorithm executed previously, where the attribute a belongs to an attribute group Ai from a total of i=1 . . . n attribute groups in the MESM, the method comprising the following steps:
• a) Replacing a desired orthogonalized boundary value
• 89 m α ortho
• for the attribute a with a modified desired orthogonalized boundary value
• 90 m α ortho , mod
• with:
• 91 m α ortho , mod = ∑ β = A i ⁢ m β ortho
• where
• βεAi:
• represents all the attributes β ε Ai that have a wider range than the attribute α, which end in the attribute α;
• and
• 92 m β ortho :
• represents the desired orthogonalized boundary values for the attributes β;
• b) Calculating an expression ‘denominatorα’ according to:
• denominatorα
• 93 ∑ β ⁢ ∈ ⁢ A i ⁢ exp ( - λ β ortho ) · M β ortho
• where
• βεAi:
• represents all the attributes β ε Ai that have a wider range than the attribute α, which end in the attribute α;
• 94 λ β ortho :
• represents the free orthogonalized parameter of the MESM for attribute β;
• and
• 95 M β ortho :
• represents the approximate boundary value for the desired orthogonalized boundary value for the attribute β;
• and
• c) Calculating the free orthogonalized parameter
• 96 λ β ortho
• according to
• 97 λ α ortho = log ⁡ ( m α ortho , mod denominator α )