| 1. |
- Blomberg, Mats, et al.
(författare)
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Speech synthesis and recognition in technical aids
- 1986
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Ingår i: STL-QPSR. ; 27:4, s. 45-65
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Tidskriftsartikel (refereegranskat)abstract
- A number of speech-producing technical aids arenowavailable for use by disabled individuals. One system which produces synthetic speech is described and its application in technical aids discussed. These applications inclde a communication aid, a symbol-to-speech system, talking terminals and a daily newspaper. A pattern-matching speech recognition system is also described and its future in the area of technical aids discussed.
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| 2. |
- Blomberg, J, et al.
(författare)
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Glycosphingolipids of a green monkey kidney cell line (GMK AH-1). Evidence for a novel pentaglycosylceramide based on globotetraosylceramide.
- 1982
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Ingår i: Biochimica et biophysica acta. - 0006-3002. ; 711:3, s. 466-77
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Tidskriftsartikel (refereegranskat)abstract
- Total non-acid glycolipid fractions have been isolated from GMK AH-1 cells grown in fetal calf serum and in horse serum. For comparison, glycolipids were also prepared from green monkey (Cercopithecus aetiops) kidney and from fetal calf serum. The major glycolipids from GMK AH-1 cells grown in fetal calf serum were isolated by silicic acid column chromatography and preparative thin-layer chromatography. These fractions were characterized mainly by thin-layer chromatography, mass spectrometry and gas chromatography. The structures of the glycolipids isolated were proposed as: Glc1 leads to 1Cer, Gal1 leads to 1Cer, Gal1 leads to 4Glc1 leads to 1Cer, Gal1 leads to 4Gal1 leads to 4Glc1 leads to 1Cer, GalNAcl leads to 3Gal1 leads to 4Gal1 leads 4Glc1 leads to 1Cer. In addition, a novel pentaglycosylceramide with the probable structure Ga1 beta 1 leads to 3GalNAc beta 1 leads to Gal alpha 1 leads to 4Gal beta 1 leads to 4Glc beta 1 leads to 1Cer was also present. THe ceramides contained mainly dihydroxy 18:1 long-chain base in combination with non-hydroxy 16:0-24:0 fatty acids. Small amounts of trihydroxy 18:0 long-chain base and hydroxy 22:0-24:0 fatty acids were also present in the mono- and diglycosylceramide fractions. The glycolipid patterns of GMK AH-1 cells grown in fetal calf serum or horse serum were identical. The pentaglycosylceramide present in the cultured cells could not be detected with certainty in the kidney tissue. The uptake of this glycolipid from the culture medium is unlikely as it seems to be lacking in calf serum.
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| 3. |
- Blomberg, Mats, et al.
(författare)
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A device for automatic speech recognition
- 1982
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Konferensbidrag (refereegranskat)abstract
- This paper is a translation of a paper originally published in the proceedings of the 1982 meeting of "Nordiska akustistka sällskapet" (The Nordic Acoustical Society), pp. 383-386. 2 DESCRIPTION OF THE RECOGNITION SYSTEM
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| 4. |
- Blomberg, Mats, et al.
(författare)
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Auditory models and isolated word recognition
- 1983
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Ingår i: STL-QPSR. ; 24:4, s. 1-15
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Tidskriftsartikel (refereegranskat)abstract
- A straightforward isolated word recognition system has been used to test different auditory models in acoustic front end processing. The models include BARK, PHON and SONE. The PHONTEMP model is based on PHON but also includes temporal forward masking. We also introduce a model, DOMIN, which is intended to measure the dominating frequency at each point along the 'basilar membrane.' All the above models were derived from an FFT-analysis, and the FFT processing is also used as a reference model. One male and one female speaker were used to test the recognition performance of the different models on a difficult vocabulary consisting of 18 Swedish consonants and 9 Swedish vowels. The results indicate that the performance of the models decreases as they become more complex. The overall recognition accuracy of FFT is 97% while it is 87% for SONE. However, the DOMIN model which is sensitive to dominant frequencies (formants) performs very well for vowels.
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| 5. |
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| 6. |
- Blomberg, Mats, et al.
(författare)
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Auditory models in isolated word recognition
- 1984
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Konferensbidrag (refereegranskat)abstract
- A straightforward isolated word recognition system has been used to test different auditory models in acoustic front end processing. The models include BARK, PHON and SONE. The PHONTEMP model is based on PHON but also includes temporal forward masking. We also introduce a model, DOMIN, which is intended to measure the dominating frequency at each point along the 'basilar membrane.' All the above models were derived from an FFT-analysis, and the FFT processing is also used as a reference model. One male and one female speaker were used to test the recognition performance of the different models on a difficult vocabulary consisting of 18 Swedish consonants and 9 Swedish vowels. The results indicate that the performance of the models decreases as they become more complex. The overall recognition accuracy of FFT is 97% while it is 87% for SONE. However, the DOMIN model which is sensitive to dominant frequencies (formants) performs very well for vowels.
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| 7. |
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| 8. |
- Blomberg, Mats, et al.
(författare)
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Effects of emphasizing transitional or stationary parts of the speech signal in a discrete utterance recognition system
- 1982
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Konferensbidrag (refereegranskat)abstract
- A pattern matching word recognition system has been modified in order to emphasize the transient parts of speech in the similarity mesure. The technique is to weight the word distances with a normalized spectral change function. A small positive effect is measured. Emphasizing the stationary parts is shown to substantially decrease the performance. Adding the time derivative of the speech parameters to the word patterns improves performance significantly. This is probaly a consequence of an improvement in the description of the transient segments.
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| 9. |
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| 10. |
- Blomberg, Mats, et al.
(författare)
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Let your voice do the dialing
- 1983
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Ingår i: Telephony. - 0040-2656 .- 2161-8690. ; , s. 68-74
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Tidskriftsartikel (refereegranskat)
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| 11. |
- Blomberg, Mats, et al.
(författare)
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Nonlinear Frequency Warp for Speech Recognition
- 1986
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Konferensbidrag (refereegranskat)abstract
- A technique of nonlinear frequency warping has been investigated for recognition of Swedish vowels. A frequency warp between two spectra is computed using a standard dynamic programming algorithm. The frequency distance, defined as the area between the obtained warping function and the diagonal, is contributing to the spectral distance. The distance between two spectra is a weighted sum of the warped amplitude distance and the frequency distance. By changing two weights, we get a gradual shift between non-warped amplitude distance, warped amplitude distance, and frequency distance. In recognition experiments on natural and synthetic vowel spectra, a metric combining the frequency and amplitude distances gave better results than using only amplitude or frequency deviation. Analysis of the results of the synthetic vowels show a reduced sensitivity to voice source and pitch variation. For the natural vowels, the recognition improvement is larger for the male and female speakers separately than for the combined groups.
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| 12. |
- Blomberg, Mats, et al.
(författare)
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Some current projects at KTH related to speech recognition
- 1986
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Konferensbidrag (refereegranskat)abstract
- Understanding and modelling the human speech understanding process requires knowledge in several domains, from auditory analysis of speech to higher linguistic processes. Integrating this knowledge into a coherent model is not the scope of this paper. Rather we want to present some projects that may add to the understanding of some components that eventually could be built into a knowledge-based speech recognition system. One project is concerned with a framework to formulate and experiment w i t h the earlier levels of speech analysis. Others deal with different kindsof auditory representationsand methods for comparing speech sounds. S t i l l another project studies the p h e t i c and ortbgraphic properties of different European languages.
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| 13. |
- Blomberg, Mats, et al.
(författare)
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Speech recognition based on a text-to-speech synthesis system
- 1987
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Konferensbidrag (refereegranskat)abstract
- A major problem in large-vocabulary speech recognition is the collection of reference data and speaker normalization. In this paper we propose the use of synthetic speech as a means of handling this problem. An experimental scheme for such a system will be described.
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| 14. |
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| 15. |
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| 16. |
- Blomberg, Mats, et al.
(författare)
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Testing some essential parameters of a word recogniser used in car noise
- 1989
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Konferensbidrag (refereegranskat)abstract
- A speaker-dependent word recognition system has been modified to improve the performance in noise. Problems with word detection and noise compensation have been addressed by using a close-talk microphone and a "noise addition" method. The reference templates are recorded in relative silence. The additional environmental noise during the recognition phase is measured and is "added" to the reference templates before using them for template matching. The recognition performance has been tested in moving cars with references recorded in parked cars. Recordings of six male speakers have been used in this report to rest the sensitivity of the recognition system to some essential parameters. The results from six male speakers and a twenty word vocabulary show that adapting the endpoint detection threshold to the noise level is essential for good performance and that noise compensation is imponant at signal-to-noise ratios below 15 dB.
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| 17. |
- Blomberg, Mats, et al.
(författare)
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Word recognition using synthesized reference templates
- 1988
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Konferensbidrag (refereegranskat)abstract
- A major problem in large‐vocabulary speech recognition is the collection of reference data and speaker normalization. In this paper, the use of synthetic speech is proposed as a means of handling this problem. An experimental scheme for such a speech recognition system will be described. A rule‐based speech synthesis procedure is used for generating the reference data. Ten male subjects participated in an experiment using a 26‐word test vocabulary recorded in a normal office room. The subjects were asked to read the words from a list with little instruction except to pronounce each word separately. The synthesis was used to build the references. No adjustments were done to the synthesis in this first stage. All the human speakers served better as reference than the synthesis. Differences between natural and synthetic speech have been analyzed in detail at the segmental level. Methods for updating the synthetic speech parameters from natural speech templates will be described. [This work has been supported by the Swedish Board of Technical Development.]
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| 18. |
- Blomberg, Mats, et al.
(författare)
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Word recognition using synthesized templates
- 1988
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Ingår i: STL-QPSR. ; 29:2-3, s. 069-081
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Tidskriftsartikel (refereegranskat)abstract
- With the ultimate aim of creating a knowledge based speech understanding system, we have set up a conceptual framework named NEBULA. In this paper we briefly describe some of the components of this framework and also report on some experiments where we use a production component for generating reference data for the recognition. The production component in the form of a speech synthesis system will ideally make the collection of training data unnecessary. Preliminary results of an isolated word recognition experiment will be presented and discussed. Several methods of interfacing the production component to the recognition/evaluation component have been pursued.
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| 19. |
- Crosnier, S, et al.
(författare)
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Speech recogniser sensitivity to the variation of different control parameters in synthetic speech
- 1989
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Konferensbidrag (refereegranskat)abstract
- Knowledge of a speech recognizer's sensitivity to different speech production parameters can be used to improve the system or to predict its behaviour in a given application. In this report, a speech recognition system has been tested using manipulated synthetic speech. A text-to-speech system was used for producing words with the 9 Swedish long vowels in CVC context. A "normal" production of each word served as reference template for the recognition system. The test set consisted of the same words where the value of one control parameter at a time was changed from its original position. The mel cepstrum distance between the reference and the manipulated word was measured. Modifying the pitch, voice source spectral slope and the first four formant frequencies had large influence on the distance, while varying formant bandwiths resulted in small effects. The relation between individual formants is different to results from experiments using natural listeners. The results indicate that the sensitivity to pitch and voice source spectrum variation will degrade the recognizer's performance in speaker-independent applications and during stress and that some form of normalisation is needed.
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| 20. |
- Elenius, K.O.E, et al.
(författare)
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Effects of emphasizing transitional or stationary parts of the speech signal in a discrete utterance recognition system
- 1981
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Ingår i: STL-QPSR. ; 22:4, s. 39-48
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Tidskriftsartikel (refereegranskat)abstract
- A pattern matching word recognition system has been modified in order to emphasize the transient parts of speech in the similarity mesure. The technique is to weight the word distances with a normalized spectral change function. A small positive effect is measured. Emphasizing the stationary parts is shown to substantially decrease the performance. Adding the time derivative of the speech parameters to the word patterns improves performance significantly. This is probaly a consequence of an improvement in the description of the transient segments.
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| 21. |
- Lundin, F, et al.
(författare)
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Voice controlled dialing in an intercom system
- 1983
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Konferensbidrag (refereegranskat)abstract
- We will describe an experiment in which we have used speech recognition for voice-controlled dialing in an intercom system. The experimental system is described and the results of the tests are discussed. Finally we present a voice-controlled intercom exchange that may be seen as the result of our study with the presentaly available technique. It is marketed by LM Ericsson telemateriel AB
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