2023

Stefan Lotz, Amore E. Nel, Robert T. Wicks, Owen W. Roberts, Nicholas E. Engelbrecht, Roelf D. Strauss, Gert J. J. Botha, Eduard P. Kontar, Alexander Pitňa and Stuart D. Bale, "The radial variation of the solar wind turbulence spectra near the kinetic break scale from Parker Solar Probe measurements", The Astrophysical Journal, Vol 942, no 2, January 2023.

Jan C. Olivier, Etienne Barnard, "Minimum phase finite impulse response filter design", IET Signal Processing, Vol 17, no 1, January 2023.

Simon Ramalepe, Thipe I. Modipa and Marelie H. Davel, "The analysis of the Sepedi-English code-switched radio news corpus", Journal of the Digital Humanities Association of Southern Africa, Vol 4, no 1, February 2023.

2022

Edrich Fourie, Marelie H. Davel and Jaco Versfeld, "Neural speech processing for whale call detection", Artificial Intelligence Research (SACAIR 2022), Communications in Computer and Information Science, Vol 1734, pp 276-290, November 2022.

Walter Heymans, Marelie H. Davel and Charl van Heerden, "Multi-style training for South African call centre audio", Artificial Intelligence Research (SACAIR 2021), Communications in Computer and Information Science, Vol 1551, pp 111-124, January 2022.

• arXiv preprint
• Published paper
• Presentation slides

Walter Heymans, Marelie H. Davel and Charl van Heerden, "Efficient acoustic feature transformation in mismatched environments using a Guided-GAN", Speech Communication, Vol 143, pp 10-20, September 2022.

• Published paper
• arXiv preprint

Thipe Modipa and Marelie H. Davel, "Two Sepedi-English code-switched speech corpora", Language Resources and Evaluation, Vol 56, no 3, pp 703-727, September 2022.

• Published paper
• SharedIt version

Coenraad Mouton and Marelie H. Davel, "Exploring layerwise decision making in DNNs", Artificial Intelligence Research (SACAIR 2021), Communications in Computer and Information Science, Vol 1551, pp 140-155, January 2022.

• arXiv preprint
• Published paper
• Presentation slides

Andrew J. Oosthuizen, Marelie H. Davel and Albert S. J. Helberg, "Multi-layer perceptron for channel state information estimation: design considerations", in Proc. Southern Africa Telecommunication Networks and Applications Conference (SATNAC 2022), pp 94-99, August 2022.

• Published paper
• Presentation slides

Andrew J. Oosthuizen, Albert S. J. Helberg and Marelie H. Davel, "Adversarial training for channel state information estimation in LTE multi-antenna systems", Artificial Intelligence Research (SACAIR 2022), Communications in Computer and Information Science, Vol 1734, pp 3-17, November 2022.

Marko Oosthuizen, Alwyn Hoffman and Marelie H. Davel, "A comparative study of graph neural network speed prediction during periods of congestion", in Proc. 14th Int. Conf. on Neural Computation theory and Applications (NCTA 2022), pp 331-338, October 2022.

Simon P. Ramalepe, Thipe I. Modipa and Marelie H. Davel, "The development of a Sepedi text generation model using transformers", in Proc. Southern Africa Telecommunication Networks and Applications Conference (SATNAC 2022), pp 51-56, August 2022.

Marthinus W. Theunissen, Coenraad Mouton and Marelie H. Davel, "The missing margin: How sample corruption affects distance to the boundary measurements in ANNs", Artificial Intelligence Research (SACAIR 2022), Communications in Computer and Information Science, Vol 1734, pp 78-92, November 2022.

• Published paper
• arXiv preprint

Ruan van der Merwe, Gregory Newman and Etienne Barnard, "Manifold characteristics that predict downstream task performance", in Proc. First Workshop on Pre-training: Perspectives, Pitfalls, and Paths Forward at ICML 2022, July 2022.

2021

Daniël G. Haasbroek and Marelie H. Davel, "Exploring neural network training dynamics through binary node activations", in Proc. Southern African Conference for AI Research (SACAIR 2020), pp 304-320, February 2021.

• Presentation slides
• Published paper

Nuette Heyns and Etienne Barnard, "Optimising word embeddings for recognised multilingual speech", in Proc. Southern African Conference for AI Research (SACAIR 2020), pp 102-116, February 2021.

• Presentation slides
• Published paper

Dylan Lamprecht and Etienne Barnard, "Using a meta-model to compensate for training-evaluation mismatches", in Proc. Southern African Conference for AI Research (SACAIR 2020), pp 321-334, February 2021.

• Presentation slides
• Published paper

Andrew Oosthuizen, Marelie H. Davel and Albert Helberg, "Exploring CNN-based automatic modulation classification using small modulation sets", in Proc. Southern Africa Telecommunication Networks and Applications Conference (SATNAC 2021), pp 20-24, November 2021.

• Published paper
• Presentation slides

Rhyno A. Strydom and Etienne Barnard, "Classifying recognised speech with deep neural networks", in Proc. Southern African Conference for AI Research (SACAIR 2020), pp 191-205, February 2021.

• Presentation slides
• Published paper

Lucas van Wyk, Marelie H. Davel and Charl van Heerden, "Unsupervised fine-tuning of speaker diarisation pipelines using silhouette coefficients", in Proc. Southern African Conference for AI Research (SACAIR 2021), pp 202-216, December 2021.

• Published paper
• Presentation slides

2020

Jacques P. Beukes, Stefan Lotz and Marelie H. Davel, "Pairwise networks for feature ranking of a geomagnetic storm model", South African Computer Journal, Vol 32, no 2, pp 35-55, December 2020.

Marelie H. Davel, "Using summary layers to probe neural network behaviour", South African Computer Journal, Vol 32, no 2, pp 102-123, December 2020.

Marelie H. Davel, Marthinus W. Theunissen, Arnold M. Pretorius and Etienne Barnard, "DNNs as layers of cooperating classifiers", in Proc. AAAI, Vol 34 no 4, pp 3725-3732, New York, February 2020.

• arXiv preprint
• Published paper
• Presentation slides

Ulrike Janke and Etienne Barnard, "MuST: A case study on the development of AI systems in the South African context", Litnet Seminars and Essays, March 2020.

Coenraad Mouton, Johannes C. Myburgh and Marelie H. Davel, "Stride and translation invariance in CNNs", Artificial Intelligence Research (SACAIR 2020), Communications in Computer and Information Science, Vol 1342, pp 267-281, 2020.

• arXiv preprint
• Published paper
• Presentation slides

Johannes C. Myburgh, Coenraad Mouton and Marelie H. Davel, "Tracking translation invariance in CNNs", Artificial Intelligence Research (SACAIR 2020), Communications in Computer and Information Science, Vol 1342, pp 282-295, 2020.

• arXiv preprint
• Published paper

Marthinus Wilhelmus Theunissen, Marelie H. Davel and Etienne Barnard, "Benign interpolation of noise in deep learning", South African Computer Journal, Vol 32, no 2, pp 80-101, December 2020.

Jan W.F. Thirion, Charl van Heerden, Oluwapelumi Giwa and Marelie H. Davel, "The South African directory enquiries (SADE) name corpus", Language Resources and Evaluation, Vol 54, issue 1, pp 155-184, March 2020. (Published online: 6 February 2019).

• Preprint
• Published paper

Arthur E.W. Venter, Marthinus W. Theunissen and Marelie H. Davel, "Pre-interpolation loss behavior in neural networks", Artificial Intelligence Research (SACAIR 2020), Communications in Computer and Information Science, Vol 1342, pp 296-309, 2020.

• arXiv preprint
• Published paper
• Presentation slides

 

2019

Marelie H. Davel, "Activation gap generators in neural networks", in Proc. South African Forum for Artificial Intelligence Research (FAIR), pp 64-76, Cape Town, South Africa, December 2019.

Dewald D. Krynauw, Marelie H. Davel and Stefan Lotz, "Solar flare prediction with temporal convolutional networks", in Proc. South African FAIR (Work in progress), Cape Town, South Africa, December 2019.

Stefan Lotz, Jacques P. Beukes and Marelie H. Davel, "Input parameter ranking for neural networks in a space weather regression problem", in Proc. South African FAIR), pp 133-144, Cape Town, South Africa, December 2019.

Stefan Lotz, Jacques Beukes and Marelie Davel, "A neural network based method for input parameter selection", in Machine Learning in Heliophysics, Amsterdam, The Netherlands, September 2019.

Arnold M. Pretorius, Etienne Barnard and Marelie H. Davel, "ReLU and sigmoidal activation functions", in Proc. South African FAIR, pp 37-48, Cape Town, South Africa, December 2019.

Marthinus W. Theunissen, Marelie H. Davel and Etienne Barnard, "Insights regarding overfitting on noise in deep learning", in Proc. South African FAIR, pp 49-63, Cape Town, South Africa, December 2019.

 

2017

Febe de Wet, Neil Kleynhans, Dirk van Compernolle and Reza Sahraeian, "Speech recognition for under-resourced languages: data sharing in hidden Markov model systems", South African Journal of Science, Vol 113, No 1/2, pp 25-33, January 2017.

Oluwapelumi Giwa and Marelie Davel, "Bilateral G2P accuracy: measuring the effect of variants", in Proc. Annual Symp. Pattern Recognition Association of South Africa and Mechatronics Int. Conf. (PRASA-RobMech), pp 208-213, Bloemfontein, South Africa, November 2017.

Oluwapelumi Giwa and Marelie Davel, "The effect of language identification accuracy on speech recognition accuracy of proper names", in Proc. Annual Symp. Pattern Recognition Association of South Africa and Mechatronics Int. Conf. (PRASA-RobMech), pp 187-192, Bloemfontein, South Africa, November 2017.

Christiaan M. van der Walt and Etienne Barnard, "Variable kernel density estimation in high-dimensional feature spaces", in Proc. AAAI Conf. on Artificial Intelligence (AAAI-17), pp 2674-2680, February 2017.

Charl van Heerden, Damianos Karakos, Karthik Narasimhan, Marelie Davel and Richard Schwartz, "Constructing sub-word units for spoken term detection", in Proc. IEEE Int. Conf. on Acoustics, Speech and Signal Processing (ICASSP), pp 5780-5784, New Orleans, Louisiana, March 2017.

Daniel R. van Niekerk, "Evaluating acoustic modelling of lexical stress for Afrikaans speech synthesis", in Proc. Annual Symp. Pattern Recognition Association of South Africa and Mechatronics Int. Conf. (PRASA-RobMech), pp 86-91, bloemfontein, South Africa, November 2017.

Daniel Rudolph van Niekerk, Charl van Heerden, Marelie Davel, Neil Kleynhans, Oddur Kjartansson, Martin Jansche and Linne Ha, "Rapid development of TTS corpora for four South African languages", in Proc. Interspeech, pp 2178-2182, Stockholm, Sweden, August 2017.

2016

Neil Kleynhans, William Hartman, Daniel van Niekerk, Charl van Heerden, Rich Schwartz, Stavros Tsakalidis and Marelie Davel, "Code-switched English pronunciation modeling for Swahili spoken term detection", Procedia Computer Science: Spoken Language Technology for Under-resourced Languages, pp 128-135, Yogyakarta, Indonesia, May 2016.

Charl van Heerden, Neil Kleynhans and Marelie Davel, "Improving the Lwazi ASR baseline", in Proc. Interspeech, pp 3529-3538, San Francisco, USA, September 2016.

Daniel van Niekerk, "Syllabification for Afrikaans speech synthesis", in Proc. Pattern Recognition Association of South Africa and Mechatronics Int. Conf. (PRASA-RobMech), pp 31-36, Stellenbosch, South Africa, December 2016.

 

2015

Jaco Badenhorst and Marelie Davel, "Synthetic triphones from trajectory-based feature distributions", in Proc. Annual Symp. Pattern Recognition Association of South Africa Int. Conf. (PRASA), pp 118-122, Port Elizabeth, South Africa, November 2015.

Marelie Davel, Damianos Karakos, Etienne Barnard, Charl van Heerden, Richard Schwartz and Stavros Tsakalidis, William Hartmann, "Exploring minimal pronunciation modeling for low resource languages", in Proc. Interspeech, pp 538-542, Dresden, Germany, September 2015.

Oluwapelumi Giwa and Marelie Davel, "Text-based Language Identification of Multilingual Names", in Proc. Annual Symp. Pattern Recognition Association of South Africa Int. Conf. (PRASA), pp 166-171, Port Elizabeth, South Africa, November 2015.

Neil Kleynhans, Febe de Wet and Etienne Barnard, "Unsupervised acoustic model training: comparing South African English and isiZulu", in Proc. Annual Symp. Pattern Recognition Association of South Africa Int. Conf. (PRASA), pp 136 - 141, Port Elizabeth, South Africa, November 2015.

Kleynhans, Neil Taylor, and Etienne Barnard, "Efficient data selection for ASR", Language Resources and Evaluation, Vol 49, issue 2, pp 327-353, June 2015.

Thipe Modipa and Marelie Davel, "Predicting vowel substitution in code-switched speech", in Proc. Annual Symp. Pattern Recognition Association of South Africa Int. Conf. (PRASA), pp 154-159, Port Elizabeth, South Africa, November 2015.

Daan Wissing, Wikus Pienaar and Daniel van Niekerk, "Palatalisation of /s/ in Afrikaans" in Stellenbosch Papers in Linguistics Plus, Vol 48, pp 137-158, 2015.

 

2014

Etienne Barnard, Marelie H. Davel, Charl van Heerden, Febe de Wet and Jaco Badenhorst, "The NCHLT Speech Corpus of the South African languages", in Proc. Int. Workshop Spoken Language Technologies for Under-resourced Languages (SLTU), pp 194-200, St Petersburg, Russia, May 2014.

Laurent Besacier, Etienne Barnard, Alexey Karpov and Tanja Schultz, "Introduction to the special issue on processing under-resourced languages", Speech Communications, Vol 56, pp 83-84, January 2014.

Laurent Besacier, Etienne Barnard, Alexey Karpov and Tanja Schultz, "Automatic speech recognition for under-resourced languages: A survey", Speech Communications, Vol 56, pp 85-100, January 2014.

Nic J. De Vries, Marelie H. Davel, Jaco Badenhorst, Willem D. Basson, Febe De Wet, Etienne Barnard and Alta De Waal, "A smartphone-based ASR data collection tool for under-resourced languages", Speech Communications, Vol 56, pp 119-131, January 2014.

Pieter De Villiers, Etienne Barnard, Charl Van Heerden and Petri Jooste, "Semi-Supervised Training for Lecture Transcription in Resource-Scarce Environments", in Proc. Annual Symp. Pattern Recognition Association of South Africa Int. Conf. (PRASA), pp 7-12, Cape Town, South Africa, November 2014.

Oluwapelumi Giwa and Marelie H. Davel, "Language identification of individual words with joint sequence models", in Proc. Interspeech, pp 1400-1404, Singapore, September 2014.

Florian Metze, Xavier Anguera, Etienne Barnard, Marelie Davel and Guillaume Gravier, "Language Independent Search in MediaEval's Spoken Web Search Task", Computer Speech & Language, Vol 28, Issue 5, pp 1066-1082, September 2014.

Raymond Molapo and Etienne Barnard, "Number pronunciation in a multilingual environment and implications for an ASR system", in Proc. Annual Symp. Pattern Recognition Association of South Africa Int. Conf. (PRASA), pp 138-141, Cape Town, South Africa, November 2014.

Raymond Molapo, Etienne Barnard, Febe de Wet, "Speech data collection in an under-resourced language within a multilingual context", in Proc. Int. Workshop Spoken Language Technologies for Under-resourced Languages (SLTU), pp 238-242, St Petersburg, Russia, May 2014.

Charl van Heerden, Marelie Davel and Etienne Barnard, "Performance analysis of a multilingual directory enquiries application", in Proc. Annual Symp. Pattern Recognition Association of South Africa Int. Conf. (PRASA), pp 258-263, Cape Town, South Africa, November 2014.

Daniel van Niekerk and Etienne Barnard, "Predicting utterance pitch targets in Yorùbá for tone realisation in speech synthesis", Speech Communications, Vol 56, pp 229-242, January 2014.

Daniel van Niekerk and Etienne Barnard, "A Target Approximation Intonation Model for Yorùbá TTS", in Proc. Interspeech, pp 36-40, Singapore, September 2014.

 

2013

Willem D. Basson and Marelie H. Davel, "Category-based phoneme-to-grapheme transliteration", in Proc. Interspeech, pp 1956 – 1960, Lyon, France, Aug. 2013.

Marelie Davel, Charl van Heerden, and Etienne Barnard. "G2P variant prediction techniques for ASR and STD", in Proc. Interspeech, pp 1831-1835, Lyon, France, Aug. 2013.

Oluwapelumi Giwa and Marelie H. Davel, "N-gram based Language Identification of Individual Words", in Proc. Annual Symp. Pattern Recognition Association of South Africa Int. Conf. (PRASA), pp 15-22, Johannesburg, South Africa, December 2013.

Allan Hanbury, Hendra Van Zyl, Cèlia Boyer and Etienne Barnard, "Adapting mobile medical information search to low-resourced areas", in Proc. IST-Africa Conf. and Exhibition (IST-Africa), pp 1-8, Nairobi, Kenya, May 2013.

Neil Kleynhans and Etienne Barnard, "Cross-bandwidth adaptation for ASR systems", in Proc. Annual Symp. Pattern Recognition Association of South Africa Int. Conf. (PRASA), pp 36-43, Johannesburg, South Africa, December 2013.

Neil Kleynhans and Etienne Barnard, "Spoken language identification system adaptation in under-resourced environments", in Proc. Annual Symp. Pattern Recognition Association of South Africa Int. Conf. (PRASA), pp 45-51, Johannesburg, South Africa, December 2013.

Florian Metze, Xavier Anguera, Etienne Barnard, Marelie Davel, and Guillaume Gravier, "The Spoken Web Search task at Mediaeval 2012", in Proc. IEEE Int. Conf. on Acoustics, Speech and Signal Processing (ICASSP), pp 8121-8125, Vancouver, Canada, May 2013.

Thipe Modipa, Marelie H. Davel and Febe de Wet , "Implications of Sepedi/English code switching for ASR systems", in Proc. Annual Symp. Pattern Recognition Association of South Africa Int. Conf. (PRASA), pp 64-69, Johannesburg, South Africa, December 2013.

Raymond Molapo, Etienne Barnard and Febe de Wet, "A Distributed Approach to Speech Resource Collection", in Proc. Annual Symp. Pattern Recognition Association of South Africa Int. Conf. (PRASA), pp 70-75, Johannesburg, South Africa, December 2013.

Tembalethu Jama Ndwe, Etienne Barnard and Thato Foko, "Correlation between rapid learnability and user preference in IVR systems for developing regions", in Proc. IST-Africa Conf. and Exhibition (IST-Africa), pp 1-9,Nairobi, Kenya, May 2013.

Tembalethu Jama Ndwe and Etienne Barnard, "Consequences of culturally inclined earcons in speech technology design for oral users in South Africa", in Proc. of the 3rd ACM Symp. on Computing for Development (DEV 2013), pp 32-39, Bangalore, India, January, 2013.

Georg Schlunz and Etienne Barnard, "A Discourse Model of Affect for Text-to-Speech Synthesis", in Proc. Annual Symp. Pattern Recognition Association of South Africa Int. Conf. (PRASA), pp 91-98, Johannesburg, South Africa, December 2013.

Christiaan van der Walt and Etienne Barnard, "Kernel bandwidth estimation for non-parametric density estimation: a comparative study", in Proc. Annual Symp. Pattern Recognition Association of South Africa Int. Conf. (PRASA), pp 107-114, Johannesburg, South Africa, December 2013.

Charl van Heerden, Marelie H. Davel and Etienne Barnard, "The semi-automated creation of stratified speech corpora", in Proc. Annual Symp. Pattern Recognition Association of South Africa Int. Conf. (PRASA), pp 115-119, Johannesburg, South Africa, December 2013.

 

2012

Jaco Badenhorst, Marelie H. Davel and Etienne Barnard, "Improved transition models for cepstral trajectories", in Proc. Annual Symp. Pattern Recognition Association of South Africa Int. Conf. (PRASA), pp 157-164, Pretoria, South Africa, November 2012.

Willem D. Basson and Marelie H. Davel, "Comparing grapheme-based and phoneme-based speech recognition for Afrikaans", in Proc. Annual Symp. Pattern Recognition Association of South Africa Int. Conf. (PRASA), pp 144-148 , Pretoria, South Africa, November 2012.

Adéle Botha, Karen Calteaux, Marlien Herselman, Aditi Sharma Grover and Etienne Barnard, "Mobile User Experience for Voice Services: A Theoretical Framework", in Proc. of the 3rd Int. Conf. on Mobile Communication for Development, pp 1-10, New Delhi, India, February 2012.

Gerrit Reinier Botha and Etienne Barnard, "Factors that affect the accuracy of text-based language identification", Computer Speech and Language, Vol 26, No 5, pp 307-320, October 2012.

Marelie H. Davel, Charl J. van Heerden and Etienne Barnard, "Validating smartphone-collected speech corpora", in Proc. Int. Workshop Spoken Language Technologies for Under-resourced Languages (SLTU), pp 68-75, Cape Town, South Africa, May 2012.

Pieter de Villiers, Petri Jooste, Charl J. van Heerden and Etienne Barnard, "Towards lecture transcription in resource-scarce environments", in Proc. Annual Symp. Pattern Recognition Association of South Africa Int. Conf. (PRASA), pp 138 -143, Pretoria, South Africa, November 2012.

Aditi Sharma Grover, Karen Calteaux, Etienne Barnard and Gerhard van Huyssteen, "A voice service for user feedback on school meals", in Proc. of the 2nd ACM Symp. on Computing for Development (DEV 2012), pp 13, Atlanta, USA, March 2012.

Florian Metze, Etienne Barnard, Marelie Davel, Charl van Heerden, Xavier Anguera, Guillaume Gravier, and Nitendra Rajput, "The Spoken Web Search task", in Proc. MediaEval Workshop, Pisa, Italy, October 2012.

Florian Metze, Nitendra Rajput, Xavier Anguera, Marelie Davel, Guillaume Gravier, Charl van Heerden, Gautam V. Mantena, Armando Muscariello, Kishore Prahallad, Igor Szöke, and Javier Tejedor, "The spoken web search task at MediaEval 2011", in Proc. Int. Conf. on Acoustics, Speech and Signal Processing (ICASSP), pp 5165-5168, Kyoto, Japan, March 2012.

Thipe I. Modipa, Marelie H. Davel and Febe de Wet, "Context-dependant modelling of English vowels in Sepedi code-switched speech", in Proc. Annual Symp. Pattern Recognition Association of South Africa Int. Conf. (PRASA), pp 173-178, Pretoria, South Africa, November 2012.

Tembalethu Jama Ndwe, Etienne Barnard and Mqhele E. Dlodlo, "Effects of application type on the choice of interaction modality in IVR systems", in Proc. South African Inst. for Computer Scientists and Information Technologists Conf. (SAICSIT), pp 236-242, Pretoria, South Africa, October 2012.

James K. Tamgno, Etienne Barnard, Claude Lishou and Morgan Richomme, "Wolof Speech Recognition Model of Digits and Limited-Vocabulary Based on HMM and ToolKit", in Proc. Computer Modelling and Simulation (UKSim), pp 389-395, Cambridge, Cambridgeshire United Kingdom, March 2012.

Jan W. F. Thirion, Marelie H. Davel and Etienne Barnard, "Multilingual pronunciation of proper names in a Southern African corpus", in Proc. Annual Symp. Pattern Recognition Association of South Africa Int. Conf. (PRASA), pp 102-108, Pretoria, South Africa, November 2012.

Charl van Heerden, Marelie H. Davel and Etienne Barnard, "Medium-vocabulary speech recognition for under-resourced languages", in Proc. Int. Workshop Spoken Language Technologies for Under-resourced Languages (SLTU), pp 146-151, Cape Town, South Africa, May 2012.

Charl J. van Heerden, Febe de Wet and Marelie H. Davel, "Automatic alignment of audiobooks in Afrikaans", in Proc. Annual Symp. Pattern Recognition Association of South Africa Int. Conf. (PRASA), pp 187-191, Pretoria, South Africa, November 2012.

Daniel van Niekerk and Etienne Barnard, "Generating fundamental frequency contours for speech synthesis in Yoruba", in Proc. Interspeech, pp 451-455, Lyon, France, Aug. 2013.

D Van Niekerk, Etienne Barnard, "Tone realisation in a Yorùbá corpus", in Proc. Int. Workshop Spoken Language Technologies for Under-resourced Languages (SLTU), pp 54-59, Cape Town, South Africa, May 2012.

 

2011