image


Conference Articles



There are 97 conference publications.

AuthorTitleBooktitleMiscDownload
Niu Zhe, Ronglai Zuo, Brian Mak, Fangyun WeiA Hong Kong Sign Language Corpus Collected from Sign-interpreted TV NewsLREC-COLING 2024May, 2024, Torino, Italy unavailable
Niu Zhe, Brian MakOn the Audio-visual Synchronization for Lip-to-Speech SynthesisProceedings of the International Conference on Computer VisionOct, 2023, Paris, France DOI
Ranzo Huang, Brian Makwav2vec 2.0 ASR for Cantonese-Speaking Older Adults in a Clinical SettingProceedings of InterspeechAug, 2023, Dublin, Ireland DOI
Helen Meng, Brian Mak, Man-wai Mak, et al.Integrated and Enhanced Pipeline System to Support Spoken Language Analytics for Screening Neurocognitive DisordersProceedings of InterspeechAug, 2023, Dublin, Ireland DOI
Ronglai Zuo, Fangyun Wei, Brian MakNatural Language-Assisted Sign Language RecognitionProceedings of the IEEE Conference on Computer Vision and Pattern RecognitionJune, 2023, Vancouver, Canada DOI
Yutong Chen, Ronglai Zuo, Fangyun Wei, Yu Wu, Shujie Liu, Brian MakTwo-Stream Network for Sign Language Recognition and TranslationAdvances in Neural Information Processing SystemsNov, 2022, New Orleans, USA DOI
Ronglai Zuo, Brian MakLocal Context-aware Self-attention for Continuous Sign Language RecognitionProceedings of InterspeechSept, 2022, Incheon, Korea DOI
Brian Mak, Raymond ChungSynthesizing Near Native-accented Speech for a Non-native Speaker by Imitating the Pronunciation and Prosody of a Native SpeakerProceedings of InterspeechSept, 2022, Incheon, Korea DOI
Ronglai Zuo, Brian MakC2SLR: Consistency-enhanced Continuous Sign Language RecognitionProceedings of the IEEE Conference on Computer Vision and Pattern RecognitionJune, 2022, New Orleans, Louisiana, USA DOI
Raymond Chung, Brian MakOn-the-fly Data Augmentation for Text-to-speech Style TransferProceedings of the IEEE Automatic Speech Recognition and Understanding WorkshopDec, 2021, Cartagena, Colombia (draft) pdf
Jinchao Li, Jianwei Yu, Ye Zi, Simon Wong, Manwai Mak, Brian Mak, Xunying Liu, Helen MengA Comparative Study of Acoustic and Linguistic Features Classification for Alzheimer’s Disease DetectionProceedings of the IEEE International Conference on Acoustics, Speech, and Signal ProcessingJune, 2021, Toronto, Canada DOI
Xinyuan Yu, Brian MakNon-parallel Many-to-many Voice Conversion by Knowledge Transfer from a Text-to-speech ModelProceedings of the IEEE International Conference on Acoustics, Speech, and Signal ProcessingJune, 2021, Toronto, Canada DOI
Yingke Zhu, Brian MakOrthogonality Regularizations for End-to-End Speaker VerificationProceedings of the Speaker and Language Recognition Workshop (Odyssey)pages 17-23, Nov, 2020, Tokyo, Japan DOI
Zhaoyu Liu, Brian MakMulti-lingual Multi-speaker Text-to-speech Synthesis for Voice Cloning with Online Speaker EnrollmentProceedings of InterspeechOctober, 2020, Shanghai, China DOI
Niu Zhe, Brian MakStochastic Fine-grained Labeling of Multi-state Sign Glosses for Continuous Sign Language RecognitionProceedings of the European Conference on Computer VisionAugust, 2020, Glasgow, United Kingdom DOI
Yingke Zhu, Brian MakOrthogonal Training for Text-independent Speaker VerificationProceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processingpages 6579-6583, May, 2020, Barcelona, Spain DOI
Yingke Zhu, Tom Ko, Brian MakMixup Learning Strategies for Text-independent Speaker VerificationProceedings of Interspeechpages 4345-4349, September, 2019, Graz, Austria (draft) pdf
Hengguan Huang, Hao Wang, Brian MakRecurrent Poisson Process Unit for Speech RecognitionProceedings of the AAAI Conference on Artificial Intelligencepages 6538-6545, January, 2019, Hawaii, USA (draft) pdf
Lahiru Samarakoon, Brian Mak, Albert Y.S. LamDomain Adaptation of End-to-end Speech Recognition in Low-resource SettingsIEEE Workshop on Spoken Language Technologypages 382-388, December, 2018, Athens, Greece (draft) pdf
Lahiru Samarakoon, Brian Mak, Albert Y.S. LamSubspace Based Sequence Discriminative Training of LSTM Acoustic Models with Feed-Forward LayersProceedings of the International Symposium of Chinese Spoken Language Processingpages 136-140, November, 2018, Taipei, Taiwan unavailable
Hengguan Huang, Brian MakWaveNet MH-SRU: Deep and Wide Multiple-history Simple Recurrent Unit for Speech RecognitionProceedings of the International Symposium of Chinese Spoken Language Processingpages 141-145, November, 2018, Taipei, Taiwan (draft) pdf
Ivan Fung, Brian MakMulti-Head Attention for End-to-End Neural Machine TranslationProceedings of the International Symposium of Chinese Spoken Language Processingpages 250-254, November, 2018, Taipei, Taiwan (draft) pdf
Wei Li, Brian MakFast Derivation of Cross-lingual Document Vectors from Self-attentive Neural Machine Translation ModelProceedings of Interspeechpages 107-111, September, 2018, Hyderabad, India (draft) pdf
Yingke Zhu, Tom Ko, David Snyder, Brian Mak, Daniel PoveySelf-Attentive Speaker Embeddings for Text-Independent Speaker VerificationProceedings of Interspeechpages 3573-3577, September, 2018, Hyderabad, India (draft) pdf
Ivan Fung, Brian MakEnd-to-end low-resource lip-reading with maxout CNN and LSTMProceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processingpages 2511-2515, April, 2018, Calgary, Canada (draft) pdf
Lahiru Samarakoon, Brian Mak, Khe Chai SimLearning Effective Factorized Hidden Layer Bases Using Student-Teacher Training for LSTM Acoustic Model AdaptationProceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processingpages 5954-5958, April, 2018, Calgary, Canada (draft) pdf
Lahiru Samarakoon, Brian MakUnsupervised Adaptation of Student DNNs Learned from Teacher RNNs for Improved ASR PerformanceProceedings of the IEEE Automatic Speech Recognition and Understanding Workshoppages 200-205, Dec, 2017, Okinawa, Japan (draft) pdf
Lahiru Samarakoon, Brian Mak, Khe Chai SimLearning Factorized Transforms for Unsupervised Adaptation of LSTM-RNN Acoustic ModelsProceedings of Interspeechpages 744-748, August, 2017, Stockholm, Sweden (draft) pdf
Hengguan Huang, Brian MakTo Improve the Robustness of LSTM-RNN Acoustic Models Using Higher-order Feedback From Multiple HistoriesProceedings of Interspeechpages 3862-3866, August, 2017, Stockholm, Sweden (draft) pdf
Wei Li, Brian MakDerivation of Document Vectors from Adaptation of LSTM Language ModelProceedings of the Conference of the European Chapter of the Association for Computational Linguisticspages 456-461, April, 2017, Valencia, Spain (draft) pdf
Lahiru Samarakoon, Khe Chai Sim, Brian MakAn Investigation Into Learning Effective Speaker Subspaces for Robust Unsupervised DNN AdaptationProceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processingpages 5035-5039, March, 2017, New Orleans, USA DOI
Yingke Zhu, Brian MakSpeeding Up Softmax Computations in DNN-based Large Vocabulary Speech Recognition by Senone Weight Vector SelectionProceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processingpages 5335-5339, March, 2017, New Orleans, USA (draft) pdf
Yingke Zhu, Brian MakAn Investigation of Adaptation Techniques for Building Acoustic Models for Hearing-impaired Children in a CAPT ApplicationProceedings of the International Symposium of Chinese Spoken Language ProcessingNovember, 2016, Tianjin, China (draft) pdf
Zhili Tan, Yingke Zhu, Man-Wai Mak, Brian MakSenone I-Vectors for Robust Speaker VerificationProceedings of the International Symposium of Chinese Spoken Language ProcessingNovember, 2016, Tianjin, China (draft) pdf
Dongpeng Chen, Brian MakDistinct Triphone Acoustic Modeling Using Deep Neural NetworksProceedings of Interspeechpages 2645-2649, September, 2015, Dresden, Germany (draft) pdf
Dongpeng Chen, Brian MakJoint Sequence Training of Phone and Grapheme Acoustic Model based on Multi-task Learning Deep Neural NetworksProceedings of Interspeechpages 1083-1086, September, 2014, Singapore (draft) pdf
Tom Ko, Brian Mak, Dongpeng ChenModeling Inter-cluster and Intra-cluster Discrimination Among TriphonesProceedings of the International Symposium of Chinese Spoken Language Processingpages 103-107, September, 2014, Singapore (draft) pdf
Dongpeng Chen, Brian Mak, Cheung-Chi Leung, Sunil SivadasJoint Acoustic Modeling of Triphones and Trigraphemes by Multi-Task Learning Deep Neural Networks for Low-Resource Speech RecognitionProceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processingpages 5592-5596, May, 2014, Florence, Italy (draft) pdf
Tom Ko, Brian MakSubspace Gaussian Mixture Model with State-dependent Subspace DimensionsProceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processingpages 1725-1729, May, 2014, Florence, Italy (draft) pdf
Dongpeng Chen, Brian MakDistinct triphone modeling by reference model weightingProceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processingpages 7150-7153, May, 2013, Vancouver, Canada (draft) pdf
Guoli Ye, Brian MakSpeaker-Ensemble Hidden Markov Modeling For Automatic Speech RecognitionProceedings of the International Symposium of Chinese Spoken Language ProcessingDec, 2012, Hong Kong (draft) pdf
Guoli Ye, Brian MakSubspace High-density Discrete Hidden Markov ModelProceedings of the European Signal Processing Conferencepages 1643-1647, August, 2012, Bucharest, Romania (draft) pdf
Guoli Ye, Dongpeng Chen, Brian MakTransition Probabilities Are More Important Than We Once ThoughtProceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processingpages 4809-4812, March, 2012, Kyoto, Japan (draft) pdf
Tom Ko, Brian MakDerivation of Eigentriphones By Weighted Principal Component AnalysisProceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processingpages 4097-4100, March, 2012, Kyoto, Japan (draft) pdf
Tom Ko, Brian MakA Fully Automated Derivation of State-based Eigentriphones for Triphone Modeling with No Tied States Using RegularizationProceedings of Interspeechpages 781-784, August, 2011, Florence, Italy (draft) pdf
Tom Ko, Brian MakEigentriphones: A Basis for Context-dependent Acoustic ModelingProceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processingpages 4892-4895, May, 2011, Prague, Czech Republic (draft) pdf
Guoli Ye, Brian MakSubvector-Quantized High-density Discrete Hidden Markov Model and its Re-estimationProceedings of the International Symposium of Chinese Spoken Language Processingpages 109-113, Nov, 2010, Taiwan (draft) pdf
Brian Mak, Tom KoProblems of Modeling Phone Deletion in Conversational Speech for Speech RecognitionProceedings of the International Symposium of Chinese Spoken Language Processingpages 114-118, Nov, 2010, Taiwan (draft) pdf
Guoli Ye, Brian MakThe Use of Subvector Quantization and Discrete Densities for Fast GMM Computation for Speaker VerificationProceedings of Interspeechpages 1481-1484, Sept, 2010, Makuhari, Japan (draft) pdf
Tom Ko, Brian MakImproving Speech Recognition by Explicit Modeling of Phone DeletionsProceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processingpages 4858-4861, March, 2010, Dallas, Texas, USA (draft) pdf
Guoli Ye, Brian Mak, Man Wai MakFast GMM Computation for Speaker Verification Using Scalar Quantization and Discrete DensitiesProceedings of Interspeechpages 2327-2330, Sept, 2009, Brighton, U.K. (draft) pdf
Brian Mak, Tom KoAutomatic Estimation of Decoding Parameters Using Large-Margin Iterative Linear ProgrammingProceedings of Interspeechpages 1219-1222, Sept, 2009, Brighton, U.K. (draft) pdf
Brian Mak, Tom KoMin-max Discriminative Training of Decoding Parameters Using Iterative Linear ProgrammingProceedings of Interspeechpages 915-918, Sept, 2008, Brisbane, Australia (draft) pdf
Chien-Lin Huang, Bin Ma, Chung-Hsien Wu, Brian Mak, Haizhou LiRobust Speaker Verification Using Short-Time Frequency with Long-Time Window and Fusion of Multi-ResolutionsProceedings of Interspeechpages 1897-1900, Sept, 2008, Brisbane, Australia (draft) pdf
Brian Mak, Benny NgDiscriminative Training by Iterative Linear Programming OptimizationProceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processingpages 4061-4064, April, 2008, Las Vegas, USA (draft) pdf
Ka-Keung Wong, Man-hung Siu, Brian MakA Model-based Estimation of Phonotactic Language Verification PerformanceProceedings of Interspeechpages 186-189, Aug, 2007, Antwerp, Belgium unavailable
Xi Yang, Man-hung Siu, Herbert Gish, Brian MakBoosting with Anti-models for Automatic Language IdentificationProceedings of Interspeechpages 342-345, Aug, 2007, Antwerp, Belgium unavailable
Brian Mak, Roger HsiaoRobustness of Several Kernel-based Fast Adaptation Methods on Noisy LVCSRProceedings of Interspeechpages 266-269, Aug, 2007, Antwerp, Belgium (draft) pdf
Tsz-Chung Lai, Brian MakUnsupervised speaker adaptation using reference speaker weightingProceedings of the International Symposium of Chinese Spoken Language Processingpages 380-389, Dec 13-16, 2006, Singapore, Edited by Q. Huo and B. Ma and E-S. Chng and H. Z. Li (draft) pdf
David Rossiter, Gibson Lam, Brian MakAutomatic Audio Indexing and Audio Playback Speed Control as Tools for Language LearningLecture Notes in Computer Science: Advances in Web Based Learning -- ICWL 2006pages 290-299, 2006, Springer Berlin / Heidelberg unavailable
Brian Mak, Tsz-Chung Lai, Roger HsiaoImproving reference speaker weighting adaptation by the use of maximum-likelihood reference speakersProceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processingvolume 1, pages 229-232, May 14-19, 2006, Toulouse, France (draft) pdf
Ivor W. Tsang, James T. Kwok, Brian Mak, Kai Zhang, Jeffrey J. PanFast Speaker Adaptation via Maximum Penalized Likelihood Kernel RegressionProceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processingvolume 1, pages 997-1000, May 14-19, 2006, Toulouse, France (draft) pdf
Man Wai Mak, Roger Hsiao, Brian MakA Comparison of Various Adaptation Methods for Speaker Verification with Limited Enrollment DataProceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processingvolume 1, pages 929-932, May 14-19, 2006, Toulouse, France (draft) pdf
Brian Mak, S. K. Au Yeung, Y. P. Lai, M. SiuHigh-density Discrete HMM with the Use of Scalar Quantization IndexingProceedings of InterspeechSept, 2005, Lisbon, Portugal (draft) pdf
R. Hsiao, Brian MakA Comparative Study of Two Kernel Eigenspace-based Speaker Adaptation Methods on Large Vocabulary Continuous Speech RecognitionProceedings of InterspeechSept, 2005, Lisbon, Portugal (draft) pdf
R. Hsiao, Brian MakKernel Eigenspace-based MLLR Adaptation Using Multiple Regression ClassesProceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processingvolume 1, pages 985-988, March 18-23, 2005, Philadelphia, USA (draft) pdf
Brian Mak, S. HoVarious Reference Speakers Determination Methods for Embedded Kernel Eigenvoice Speaker AdaptationProceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processingvolume 1, pages 981-984, March 18-23, 2005, Philadelphia, USA (draft) pdf
C. W. Yip, H. K. Lo, Brian MakPassenger Route Guidance for Multi-modal NetworksProceedings of the International Conference on Application of Information and Communication Technology in Transport Systems in Developing CountriesAugust, 2004, Sri Lanka unavailable
Brian Mak, R. HsiaoImproving Eigenspace-based MLLR Adaptation by Kernel PCAProceedings of Interspeechvolume I, pages 13-16, October 14-18, 2004, Jeju Island, South Korea (draft) pdf
Brian Mak, S. Ho, J. T. KwokSpeedup of Kernel Eigenvoice Speaker Adaptation by Embedded Kernel PCAProceedings of Interspeechvolume IV, pages 2913-2916, October 14-18, 2004, Jeju Island, South Korea (draft) pdf
R. Hsiao, Brian MakDiscriminative Feature Transformation By Guided Discriminative TrainingProceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processingvolume I, pages 897-900, May, 2004, Montreal, Canada (draft) pdf
Brian Mak, J. T. Kwok, S. HoA Study of Various Composite Kernels for Kernel Eigenvoice Speaker AdaptationProceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processingvolume I, pages 325-328, May, 2004, Montreal, Canada (draft) pdf
J. T. Kwok, Brian Mak, S. HoEigenvoice Speaker Adaptation via Composite Kernel PCAAdvances in Neural Information Processing Systems2004, Cambridge, MA, MIT Press, Edited by Thrun, S. and Saul, L. and Scholkopf, B. (draft) pdf
S. Ho, Brian MakJoint Estimation of Thresholds in a Bi-threshold Verification ProblemProceedings of Interspeechpages 893-896, September, 2003, Geneva, Switzerland (draft) pdf
Brian Mak, K. W. ChanPruning Transitions in a Hidden Markov Model with Optimal Brain SurgeonProceedings of Interspeechpages 2521-2524, September, 2003, Geneva, Switzerland (draft) pdf
Brian Mak, M. H. Siu, M. Ng, Y. C. Tam, Y. C. Chan, K. W. Chan, K. Y. Leung, S. Ho, F. H. Chong, J. Wong, J. LoPLASER: Pronunciation Learning via Automatic Speech RecognitionProceedings of HLT-NAACLMay, 2003, Edmonton, Canada (draft) pdf
Brian Mak, Y. C. TamDiscriminative Training of Auditory Filters of Different Shapes for Robust Speech RecognitionProceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processingvolume 2, pages 45-48, April, 2003, Hong Kong (draft) pdf
Brian Mak, Y. C. TamPerformance of Discriminatively Trained Auditory Features on Aurora2 and Aurora3Proceedings of Interspeechvolume 1, pages 33-36, September, 2002, Denver, Colorado, USA (draft) pdf
K. W. Gan, C. Y. Wang, Brian MakKnowledge-based Sense Pruning using the HowNet: An Alternative to Word Sense DisambiguationProceedings of the International Symposium of Chinese Spoken Language Processingpages 189-192, August, 2002, Taiwan (draft) pdf
Brian Mak, Y. C. Tam, Q. LiDiscriminative Auditory Features for Robust Speech RecognitionProceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processingvolume 1, pages 381-384, May, 2002, Orlando, Florida, USA (draft) pdf
Y. C. Tam, Brian MakAn Alternative Approach of Finding Competing Hypotheses for Better Minimum Classification Error TrainingProceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processingvolume 1, pages 101-104, May, 2002, Orlando, Florida, USA (draft) pdf
Y. C. Tam, Brian MakDevelopment of an Asynchronous Multi-band System for Continuous Speech RecognitionProceedings of Interspeechvolume 1, pages 575-578, September, 2001, Aalborg, Denmark (draft) pdf
K. M. Wong, Brian MakRapid Speaker Adaptation Using MLLR and Subspace Regression ClassesProceedings of Interspeechvolume 2, pages 1253-1256, September, 2001, Aalborg, Denmark (draft) pdf
Y. C. Chan, M. Siu, Brian MakPruning of State-Tying Tree using Bayesian Information Criterion with Multiple MixturesProceedings of Interspeechvolume IV, pages 294-297, 2000, Beijing, China (draft) pdf
Y. C. Tam, Brian MakOptimization of Sub-Band Weights Using Simulated Noisy Speech in Multi-Band Speech RecognitionProceedings of Interspeechvolume I, pages 313-316, 2000, Beijing, China (draft) pdf
Brian Mak, Y. C. TamAsynchrony with Re-Trained Transition Probabilities Improves Performance in Multi-Band Speech RecognitionProceedings of Interspeechvolume IV, pages 149-152, 2000, Beijing, China (draft) pdf
K. M. Wong, Brian MakMAP Adaptation with Subspace Regression Classes and TyingProceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processingvolume 3, pages 1551-1554, 2000, Istanbul, Turkey (draft) pdf
Brian Mak, E. BocchieriTraining of Context-Dependent Subspace Distribution Clustering Hidden Markov ModelProceedings of the International Conference on Spoken Language Processingvolume 1, pages 308-311, 1998, Sydney, Australia (draft) pdf
Brian Mak, E. BocchieriTraining of Subspace Distribution Clustering Hidden Markov ModelProceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processingvolume 2, pages 673-676, 1998, Seattle, Washington, USA (draft) pdf
Brian Mak, E. Bocchieri, E. BarnardStream Derivation and Clustering Schemes for Subspace Distribution Clustering HMMProceedings of the IEEE Automatic Speech Recognition and Understanding Workshoppages 339-346, 1997, Santa Barbara, California, USA (draft) pdf
E. Bocchieri, Brian MakSubspace Distribution Clustering for Continuous Observation Density Hidden Markov ModelsProceedings of the European Conference on Speech Communication and Technologyvolume 1, pages 107-110, 1997, Rhodes, Greece (draft) pdf
Brian MakCombining ANNs to Improve Phone RecognitionProceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processingvolume 4, pages 3253-3256, 1997, Munich, Germany (draft) pdf
Brian Mak, E. BarnardPhone Clustering Using the Bhattacharyya DistanceProceedings of the International Conference on Spoken Language Processingvolume 4, pages 2005-2008, 1996, Philadelphia, USA (draft) pdf
R. Cole, Y. Yan, Brian Mak, M. Fanty, T. BaileyThe Contribution of Consonants Versus Vowels to Word Recognition in Fluent SpeechProceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processingvolume 2, pages 853-856, 1996, Atlanta, Georgia, USA (draft) pdf
Tan Lee, P. C. Ching, L. W. Chan, Brian MakAn NN Based Tone Classifier For CantoneseInternational Joint Conference on Neural Networksvolume 1, pages 287-290, 1993, Japan (draft) pdf
Brian Mak, J. Junqua, B. ReavesA Robust Speech/Non-Speech Detection Algorithm Using Time and Frequency-based FeaturesProceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processingvolume 1, pages 269-272, 1992, San Francisco, California, USA (draft) pdf
Brian Mak, O. EgeciogluCommunication Parameter Tests and Parallel Back Propagation Algorithms on iPSC/2 Hypercube MultiprocessorProceedings of the Fifth Distributed Memory Computer Conferencevolume 2, pages 1353-1364, 1990, South Carolina, USA (draft) pdf