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Efficient high-order hidden Markov modelling

Dissertation (Ph. D.) -- University of Stellenbosch, 1997.

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Bibliographic Details
Main Author: Du Preez, Johan Adam
Other Authors: Barnard, E.
Format: Thesis
Language:English
Published: Stellenbosch : Stellenbosch University 2012
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access_status_str Open Access
author Du Preez, Johan Adam
author2 Barnard, E.
author_browse Barnard, E.
Du Preez, Johan Adam
author_facet Barnard, E.
Du Preez, Johan Adam
author_sort Du Preez, Johan Adam
collection Thesis
dc_rights_str_mv Stellenbosch University
description Dissertation (Ph. D.) -- University of Stellenbosch, 1997.
format Thesis
id oai:scholar.sun.ac.za:10019.1/55523
institution Stellenbosch University (South Africa)
language English
last_indexed 2026-06-10T12:45:16.097Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository
publishDate 2012
publishDateRange 2012
publishDateSort 2012
publisher Stellenbosch : Stellenbosch University
publisherStr Stellenbosch : Stellenbosch University
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source_str SUNScholar — Stellenbosch University Repository
spelling oai:scholar.sun.ac.za:10019.1/55523 Efficient high-order hidden Markov modelling Du Preez, Johan Adam Barnard, E. Weber, D. M. Stellenbosch University. Faculty of Engineering. Dept. of Electrical & Electronic Engineering. Automatic speech recognition Markov processes Dissertations -- Electronic engineering Dissertation (Ph. D.) -- University of Stellenbosch, 1997. Currently, first-order hidden Markov models (HMMs) form the backbone around which most automatic speech processing applications are built. Their higher-order extensions are known to be more powerful, but, due to their complexity and computational demands, they are seldomly used. It is the purpose of this work to advance their application. In this work we unify HMMs of all orders by deriving and proving the Order rEDucing (ORED) algorithm. This algorithm, will reduce any higher-order HMM (also mixed-order) to an equivalent first-order representation. This makes it possible to process any higher-order HMM using known first-order algorithms, thereby making unnecessary the current approach to extending specific HMM algorithms to specific higher orders. It also provides an alternative theoretical basis to reason about high-order HMMs. From this perspective high-order transition probabilities are simply powerful mathematical specifications of first-order topology. We use this insight to explain old topologies and to design new ones. We address computational concerns by developing the Fast Incremental Training (FIT) algorithm. This algorithm avoids training redundant high-order probabilities by noting which lower-order transition probabilities are zero. This considerably reduces the memory and processor requirements during training. In addition, the resultant models have far fewer parameters and generalise better on previously unseen data. To share the practical applicability of our methodology we apply it to automatic language recognition. We find that it compares well with systems that require expensive transcribed databases (ours system does not require this). Doctoral 2012-08-27T11:37:06Z 2012-08-27T11:37:06Z 1997 Thesis http://hdl.handle.net/10019.1/55523 en Stellenbosch University 166 pages : ill. application/pdf Stellenbosch : Stellenbosch University
spellingShingle Automatic speech recognition
Markov processes
Dissertations -- Electronic engineering
Du Preez, Johan Adam
Efficient high-order hidden Markov modelling
title Efficient high-order hidden Markov modelling
title_full Efficient high-order hidden Markov modelling
title_fullStr Efficient high-order hidden Markov modelling
title_full_unstemmed Efficient high-order hidden Markov modelling
title_short Efficient high-order hidden Markov modelling
title_sort efficient high order hidden markov modelling
topic Automatic speech recognition
Markov processes
Dissertations -- Electronic engineering
url http://hdl.handle.net/10019.1/55523
work_keys_str_mv AT dupreezjohanadam efficienthighorderhiddenmarkovmodelling