A problem with DTW algorithm

*Hello every boddy.***

I'm working on a speech processing projet "Keyword Spotting" and I need a Matlab code for "Segmental Dynamic time Warpping" algorithm

actually I have 2 strings.the first one is a long string that represents the utterance and the second one is a small string that represents a template keyword.

I have to compare the small string with each portion of the long string.How can I do that?

the approach that I'm working on it uses Segmental Dynamic time Wrapping But I can not undrestand it.

can anybody help me?I need it quickely best regard.Shayan