too many combinations: Transition probability etc.
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too many combinations: Transition probability etc.

 
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John
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Posted: Thu Dec 01, 2005 12:51 am    Post subject: too many combinations: Transition probability etc. Reply with quote

Hi

I am trying to do some statistics, but I don't know how to solve the problem
I am working on.

I have N speech segments and I perform a 10th order LPC-analysis of each
segment and get a 10-dimensional LPC-vector A(j)=[a1(j),a2(j),....a10(j)]
for j=1 to N.

I then convert all A(j) to B(j)=[c1(j),c2(j),......,c10(j)] where the
coefficients of B(j) are the LSF-coefficients corresponding to the
LPC-vector A(j).

I want to figure out what:

- the probability of B(j) given B(j-1) is ? (transition probability)
- the probability of B(j) ?

How do I do that?

My thoughts:
The first step would be to define a discrete space S of outcomes for B(j),
but the number of possible outcomes is very large. The coefficients of B(j)
each
have a dynamic range from 0 to pi. If I use a discrete range from
0,0.01,0.02,..........,3.14 that is 315 possible outcomes for any
coefficient in B(j). Since B(j) is a 10-dimensional
vector I have 315^10 possible outcomes in the space S. That number is way
too big to do any realistic computation in matlab......
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Peter K.
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Posted: Thu Dec 01, 2005 1:17 am    Post subject: Re: too many combinations: Transition probability etc. Reply with quote

John wrote:

Quote:
I am trying to do some statistics, but I don't know how to solve the problem
I am working on.

I have N speech segments and I perform a 10th order LPC-analysis of each
segment and get a 10-dimensional LPC-vector A(j)=[a1(j),a2(j),....a10(j)]
for j=1 to N.

I then convert all A(j) to B(j)=[c1(j),c2(j),......,c10(j)] where the
coefficients of B(j) are the LSF-coefficients corresponding to the
LPC-vector A(j).

I want to figure out what:

- the probability of B(j) given B(j-1) is ? (transition probability)
- the probability of B(j) ?

How do I do that?

1. Calculate Pr[ B(j) | B(j-1) ].

2. Calculate Pr[ B(j) ] = sum{k = 0 to N-1} Pr[ B(j) | B(k) ]

Quote:
My thoughts:
The first step would be to define a discrete space S of outcomes for B(j),
but the number of possible outcomes is very large. The coefficients of B(j)
each
have a dynamic range from 0 to pi. If I use a discrete range from
0,0.01,0.02,..........,3.14 that is 315 possible outcomes for any
coefficient in B(j). Since B(j) is a 10-dimensional
vector I have 315^10 possible outcomes in the space S. That number is way
too big to do any realistic computation in matlab......

Don't quantize nearly so finely and use vector quantization rather than
quantizing the individual elements.

Ciao,

Peter K.
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