| 1. |
- Barabash, Stas, et al.
(författare)
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Mars Orbiting Plasma Surveyor (MOPS)
- 2006
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Ingår i: Proceedings of the 6th IAA International Conference on Low-Cost Planetary Missions. ; , s. 227-232
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Mars Orbiting Plasma Surveyor (MOPS) is a microsatellite mission focused on studies of the near -Mars environment and the planet - solar wind interaction. The recent findings by the ESA Mars Express mission further highlighted the complexity of the processes taking place at the planet resulting from the solar wind interaction that strongly affect the planet's atmosphere. However, despite many previous Martian missions carrying different types of space plasma experiments, a comprehensive investigation including simultaneous measurements of particles, fields, and waves has never been performed. We consider a spinning spacecraft of a wet mass of 76.1 kg with a 9.7 kg payload, which can “hitchhike” on another platform until Mars orbit insertion, and then be released into a suitable orbit. The spacecraft design is based on the experience gained in very successful Swedish space plasma missions, Viking, Freja, Astrid-1, and Astrid-2. In the present mission design, the MOPS spacecraft is equipped with its own 1m high gain antenna for direct communication with the Earth. The payload includes a wave experiment with wire booms, magnetometer with a rigid boom, Langmuir probes, electron and ion energy spectrometers and an ion mass analyzer. An energetic neutral atom imager and an UV photometer may complete the core payload. One of the proposed scenarios is piggy - backing on the Russian Phobos - Grunt mission to be launched to Mars in 2011.
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| 2. |
- Batliner, A., et al.
(författare)
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The PF STAR Children’s Speech Corpus
- 2005
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Ingår i: 9th European Conference on Speech Communication and Technology. ; , s. 3761-3764
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Konferensbidrag (refereegranskat)abstract
- This paper describes the corpus of recordings of children's speech which was collected as part of the EU FP5 PF_STAR project. The corpus contains more than 60 hours of speech, including read and imitated native-language speech in British English, German and Swedish, read and imitated non-native-language English speech from German, Italian and Swedish children, and native-language spontaneous and emotional speech in English and German.
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| 3. |
- Bimbot, F, et al.
(författare)
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An overwiev of the CAVE project research activities in speaker verification
- 2000
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Ingår i: Speech Communication. - 0167-6393 .- 1872-7182. ; 31:2-3, s. 155-180
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Tidskriftsartikel (refereegranskat)abstract
- This article presents an overview of the research activities carried out in the European CAVE project, which focused on text-dependent speaker verification on the telephone network using whole word Hidden Markov Models. It documents in detail various aspects of the technology and the methodology used within the project. In particular, it addresses the issue of model estimation in the context of limited enrollment data and the problem of a posteriori decision threshold setting. Experiments are carried out on the realistic telephone speech database SESP. State-of-the-art performance levels are obtained, which validates the technical approaches developed and assessed during the project as well as the working infrastructure which facilitated cooperation between the partners.
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| 4. |
- Blomberg, Lars, et al.
(författare)
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Electric Field Diagnostics in the Jovian System : Brief Scientific Case and Instrumentation Overview
- 2006
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Ingår i: Proceedings of the 6th IAA International Conference on Low-Cost Planetary Missions. ; , s. 335-340
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The Jovian plasma environment exhibits a variety of plasma flow interactions with magnetised as well as unmagnetised bodies, making it a good venue for furthering our understanding of solar wind - magnetosphere / ionosphere interactions. On an overall scale the solar wind interacts with the Jovian magnetosphere, much like at Earth but with vastly different temporal and spatial scales. Inside the Jovian magnetosphere the co-rotating plasma interacts with the inner moons. The latter interaction is slower and more stable than the corresponding interaction between the solar wind and the planets, and can thus provide additional information on the principles of the interaction mechanisms. Because of the wealth of expected low-frequency waves, as well as the predicted quasi-static electric fields and plasma drifts in the interaction regions between different parts of the Jovian system, a most valuable component in future payloads would be a double-probe electric field instrument. Recent developments in low-mass instrumentation facilitate electric field measurements on spinning planetary spacecraft, which we here exemplify.
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| 5. |
- Blomberg, Mats
(författare)
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Collection and recognition of children s speech in the PF-Star project
- 2003
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Konferensbidrag (refereegranskat)abstract
- This paper reports on the recording and planned research activities on recognition of children’s speech in the EU-project PF-Star. The task is quite more difficult than recognition of adult speech for several reasons. High fundamental frequency and formant frequencies change the spectral shape of the speech signal. Also the pronunciation and the use of language differs from adult speech. One objective in PF-Star is to collect speech data for the project partners’ languages and to detect and analyse major difficulties.Possible ways of reducing these problems will be explored.
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| 6. |
- Blomberg, Mats, et al.
(författare)
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Estimating speaker characteristics for speech recognition
- 2009
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Ingår i: Proceedings of Fonetik 2009. - Stockholm : Stockholm University. - 9789163348921 - 9789163348938 ; , s. 154-158
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A speaker-characteristic-based hierarchic tree of speech recognition models is designed. The leaves of the tree contain model sets, which are created by transforming a conventionally trained set using leaf-specific speaker profile vectors. The non-leaf models are formed by merging the models of their child nodes. During recognition, a maximum likelihood criterion is followed to traverse the tree from the root to a leaf. The computational load for estimating one- (vocal tract length) and fourdimensional speaker profile vectors (vocal tractlength, two spectral slope parameters andmodel variance scaling) is reduced to a fraction compared to that of an exhaustive search among all leaf nodes. Recognition experiments on children’s connected digits using adult models exhibit similar recognition performance for the exhaustive and the one-dimensional tree search. Further error reduction is achieved with the four-dimensional tree. The estimated speaker properties are analyzed and discussed.
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| 7. |
- Blomberg, Mats, et al.
(författare)
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Investigating Explicit Model Transformations for Speaker Normalization
- 2008
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Ingår i: Proceedings of ISCA ITRW Speech Analysis and Processing for Knowledge Discovery. - Aalborg, Denmark : ISCA/AAU. - 9788792328007
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Konferensbidrag (refereegranskat)abstract
- In this work we extend the test utterance adaptation techniqueused in vocal tract length normalization to a larger number ofspeaker characteristic features. We perform partially joint estimation of four features: the VTLN warping factor, the corner position of the piece-wise linear warping function, spectral tilt in voiced segments, and model variance scaling. In experiments on the Swedish PF-Star children database, joint estimation of warping factor and variance scaling lowered the recognition error rate compared to warping factor alone.
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| 8. |
- Blomberg, Mats, et al.
(författare)
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Knowledge-Rich Model Transformations for SpeakerKnowledge-Rich Model Transformations for Speaker Normalization in Speech Recognition
- 2008
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Ingår i: Proceedings, FONETIK 2008, Department of Linguistics, University of Gothenburg. - 9789197719605 ; , s. 37-40
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this work we extend the test utterance adaptationtechnique used in vocal tract length normalizationto a larger number of speaker characteristicfeatures. We perform partially jointestimation of four features: the VTLN warpingfactor, the corner position of the piece-wise linearwarping function, spectral tilt in voicedsegments, and model variance scaling. In experimentson the Swedish PF-Star children database,joint estimation of warping factor andvariance scaling lowers the recognition errorrate compared to warping factor alone.
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| 9. |
- Blomberg, Mats
(författare)
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Phoneme recognition for the hearing impaired
- 2002
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Konferensbidrag (refereegranskat)abstract
- This paper describes an automatic speech recognition system designed to investigate the use of phoneme recognition as a hearing aid in telephone communication. The system was tested in two experiments. The first involved 19 normal hearing subjects with a simulated severe hearing impairment. The second involved 5 hearing impaired subjects. In both studies we used a procedure called Speech Tracking to measure the effective communication speed between two persons. A substantial improvement was found in both cases.
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| 10. |
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