Prof. Juha Karhunen's homepage



Juha Karhunen is half-time Professor of Computer Science (Specification area: Neural networks and signal processing) in Helsinki University of Technology (HUT) (in Finnish: Teknillinen korkeakoulu, abbreviated TKK), Espoo, Finland. He is working in the new Department of Information and Computer Science at the new Faculty of Information and Natural Sciences. The organization of TKK was restructured from 1st January 2008. Our former Laboratory of Computer and Information Science was merged with the laboratory of Theoretical Computer Science to form the new department. It hosts two national Centres of Excellence (top research units) selected by the Academy of Finland. I belong to the Adaptive Informatics Research Centre, whose former name up to December 2005 was Neural Networks Research Centre.

Contents:

Updated November 18, 2009

Contact information

Room B327
Department of Information and Computer Science
P.O.B. 5400 (Computer Science Building, Konemiehentie 2)
FIN-02015 HUT, Espoo
FINLAND

Tel. +358-9-451 3270
Mobile: +358-400-817 276
Fax. +358-9-451 3277

E-mail Juha.Karhunen@hut.fi

Career

Curriculum vitae
A complete List of publications. See below for my publications available in electronic form.

Research activities

Bayesian methods in graphical modeling and neural networks, in particular unsupervised variational Bayesian learning (also called Bayesian ensemble learning). For more detailed information, see the research report of our Bayes group covering the years 2006-2007, and older ones covering the years 2004-2005, 2002-2003, and 2000-2001.

Independent component analysis (ICA), blind source separation (BSS), and their extensions. For more detailed information, see the research report of our ICA group covering the years 2006-2007, and older ones covering the years 2004-2005, 2002-2003, as well as theoretical ICA research in 2000-2001, and applications of ICA in 2000-2001.

Applications of ICA and BSS and Bayesian methods, especially to signal processing. For more details, see the research reports of the Bayes and ICA groups given above.

Robust principal component analysis (PCA) and missing values in PCA.

Information about my older research efforts on nonlinear PCA, ICA and BSS, and their extensions, as well as on subspace methods in CDMA can be found in my publications as well as in the triennial report (covering the years 1997-1999) and quinquennial report (covering the years 1994-1998) of our laboratory, available here.

ICA book

Hyvärinen, A., Karhunen, J., and Oja, E., Independent Component Analysis. J. Wiley 2001, 481+xxii pages.
See the homepage of this comprehensive textbook for more information and ordering instructions, as well as for a Japanese translation (2005) and Chinese translation (2007).

Lecture or seminar courses at HUT

- Lecture course Machine Learning and Neural Networks, lectured for the first time in November-December 2007, and then yearly at the same time. Belongs to our department's international MacadamiaM.Sc. study programme.

Graduate courses on varying topics:
- In spring 2009, a seminar course on Nature-Inspired Computing.
- In spring 2006, a lecture course on Independent Component Analysis.
- In spring 2004, a seminar course on Information Theory and Machine Learning.
- In spring 2003, a seminar course on Support Vector Machines and Kernel Methods.

Memberships in scientific organizations

Senior member of IEEE (The Institute of Electrical and Electronics Engineers).
Member of the Pattern Recognition Society of Finland. Also member of IAPR (International Association for Pattern Recognition).
member of INNS (International Neural Network Society).
Member of the Blind DSP Subcommittee of the IEEE Circuits and Systems Society.

Memberships in editorial boards of journals

Member of the editorial board of Neurocomputing, 1997-2004.
Member of the editorial board of Neural Processing Letters, 1999-2003; again 2008-.

Selected publications

2009

Jutten, C., Babaie-Zadeh, M., and Karhunen, J., "Nonlinear Mixtures". A review chapter in the book C. Jutten and P. Comon (Eds.), Handbook of Blind Source Separation, Independent Component Analysis and Applications. Academic Press, in press, 48 pages.

Kuusela, M., Raiko, T., Honkela, A., and Karhunen, J., A Gradient-Based Algorithm Competitive with Variational Bayesian EM for Mixture of Gaussians. In Proc. of the IEEE 2009 Int. Conf. on Neural Networks (IJCNN2009), Atlanta, Georgia, USA, June 2009, pp. 1688--1695.

Luttinen, J., Ilin, A., and Karhunen, J., Bayesian Robust PCA for Incomplete Data. In Proc. of the 8th Int. Conf. on Independent Component Analysis and Signal Separation (ICA 2009), Paraty, Brazil, March 15-18, 2009. Published in Lecture Notes in Computer Science, vol. 5441, Springer-Verlag, 2009, pp. 66-73.

2008

Raiko, T., Ilin, A., and Karhunen, J., Principal Component Analysis for Sparse High-Dimensional Data. In Proc. of the 14th Int. Conf. on Neural Information Processing (ICONIP2007), Kitakyushu, Japan, November 13-16, 2007. Published in Lecture Notes in Computer Science, vol. 4985, Springer-Verlag, 2008, pp. 566-575.

Honkela, A., Tornio, M., Raiko, T., and Karhunen, J., Natural Conjugate Gradient in Variational Inference. In Proc. of the 14th Int. Conf. on Neural Information Processing (ICONIP2007), Special session on ``Information geometry and information theory in machine learning'', Kitakyushu, Japan, November 13-16, 2007. Published in Lecture Notes in Computer Science, vol. 4985, Springer-Verlag, 2008, pp. 305-314.

Raiko, T., Puolamäki, K., Karhunen, J., Hollmén, J., Honkela, A., Kaski, S., Mannila, H., Oja, E., and Simula, O., Macadamia: Master's Programme in Machine Learning and Data Mining. In Teaching Machine Learning: Workshop on open problems and new directions, Saint-Étienne, France, May 2008.

Honkela, A., Harva, M., Raiko, T., and Karhunen, J., Variational Inference and Learning for Continuous-Time Nonlinear State-Space Models. In Proc. of PASCAL 2008 Workshop on Approximate Inference in Stochastic Processes and Dynamical Systems, Cumberland Lodge, UK, May 2008.

2007

Raiko, T., Valpola, H., Harva, M., and Karhunen, J., Building Blocks for Variational Bayesian Learning of Latent Variable Models. Journal of Machine Learning Research, Vol. 8, January 2007, pp. 155-201.

Karhunen, J., and Ukkonen, T., Extending ICA for Finding Jointly Dependent Components from Two Related Data Sets. Neurocomputing, Vol. 70, Issues 16-18, October 2007, pp. 2969-2769. Publisher's electronic version.

Honkela, A., Valpola, H., Ilin, A., and Karhunen, J.,, Blind Separation of Nonlinear Mixtures by Variational Bayesian Learning. Digital Signal Processing, Special issue on Bayesian Source Separation, Vol. 17, Issue 5, September 2007, pp. 914-934.

Tornio, M., Honkela, A., and Karhunen, J., Time Series Prediction with Variational Bayesian Nonlinear State-Space Models. In Proc. of the European Symp. on Time Series Prediction (ESTSP'07), Espoo, Finland, February 7-9, 2007, pp. 11-19.

Raiko, T., Ilin, A., and Karhunen, J., Principal Component Analysis for Large Scale Problems with Lots of Missing Values. In Proc. of the 12th European Conf. on Machine Learning (ECML 2007), Warsaw, Poland, September 2007, published in J. Kok et al. (Eds.), Lecture Notes in Artificial Intelligence, vol. 4701, Springer-Verlag, 2007, pp. 691-698.

2006

Karhunen, J., and Ukkonen, T., Generalizing Independent Component Analysis for Two Related Data Sets. In Proc. of the IEEE 2006 Int. Conf. on Neural Networks / 2006 IEEE World Congress on Computational Intelligence (IJCNN2006/WCCI2006), Vancouver, Canada, July 2006, pp. 1822-1829.

Raju, K., Ristaniemi, T., Karhunen, J., and Oja, E., Jammer Suppression in DS-CDMA Arrays Using Independent Component Analysis. IEEE Trans. on Wireless Communications, Vol. 5, No. 1, January 2006, pp. 77-82.

Raiko, T., Tornio, M., Honkela, A., and Karhunen, J., State Inference in Variational Bayesian Nonlinear State-Space Models. In J. Rosca, D. Erdogmus, J. Principe, and S. Haykin (Eds.), Independent Component Analysis and Blind Signal Separation, 6th Int. Conf. (ICA2006). Lecture Notes in Computer Science, vol. 3889, Springer 2006, pp. 222-229. (Charleston, South Carolina, USA, March 5-8, 2006.)

2005

Harva, M., Raiko, T., Honkela, A., Valpola, H., and Karhunen, J., Bayes Blocks: An Implementation of the Variational Bayesian Building Blocks Framework. In Proc. of the 21st Conf. on Uncertainty in Artificial Intelligence (UAI2005), Edinburgh, United Kingdom, July 26-29, 2005, pp. 259-266.

2004

Jutten, C., and Karhunen, J., Advances in Blind Source Separation (BSS) and Independent Component Analysis (ICA) for Nonlinear Mixtures. Int. J. Neural Systems , Vol. 14, No. 5, 2004, pp. 267-292.

Valpola, H., Harva, M, and Karhunen, J., Hierachical Models of Variance Sources. Signal Processing , Vol. 84, No. 2, February 2004, pp. 267-282.

Raju, K., Ristaniemi, T., and Karhunen, J., Semi-Blind Interference Suppression on Coherent Multipath Environments. In Proc. of the First Int. Symp. on Control, Communications, and Signal Processing (ISCCSP2004), Hammamet, Tunisia, March 21-24,2004.

2003

Jutten, C., and Karhunen, J., Advances in Nonlinear Blind Source Separation. In Proc. of the 4th Int. Symp. on Independent Component Analysis and Blind Signal Separation (ICA2003), Nara, Japan, April 1-4, 2003, pp. 245-256.

Ristaniemi, T., Raju, K., Karhunen, J., and Oja, E., Inter-Cell Interference Cancellation in CDMA Array Systems by Independent Component Analysis. In Proc. of the 4th Int. Symp. on Independent Component Analysis and Blind Signal Separation (ICA2003), Nara, Japan, April 1-4, 2003, pp. 739-744.

Valpola, H., Harva, M., and Karhunen, J., Hierachical Models of Variance Sources. In Proc. of the 4th Int. Symp. on Independent Component Analysis and Blind Signal Separation (ICA2003), Nara, Japan, April 1-4, 2003, pp. 83-88.

Valpola, H., Östman, T., and Karhunen, J., Nonlinear Independent Factor Analysis by Hierarchical Models. In Proc. of the 4th Int. Symp. on Independent Component Analysis and Blind Signal Separation (ICA2003), Nara, Japan, April 1-4, 2003, pp. 257-262.

Valpola, H., Oja, E., Ilin, A., Honkela, A., and Karhunen, J., Nonlinear Blind Source Separation by Variational Bayesian Learning. IEICE Transactions (Japan), Vol. E86-A, No. 3, March 2003, pp. 532-541.

Raiko, T., Valpola, H., Östman, T., and Karhunen, J., Missing Values in Hierarchical Nonlinear Factor Analysis. In Proc. of Int. Conf. on Artificial Neural Networks and Neural Information Processing (ICANN/ICONIP 2003), Istambul, Turkey, June 26-29, 2003, pp. 185-188.

Honkela, A., Valpola, H., and Karhunen, J., Accelerating Cyclic Update Algorithms for Parameter Estimation by Pattern Searches. Neural Processing Latters, Vol. 17, No. 2, April 2003, pp. 191-203.

2002

Valpola, H., and Karhunen, J., An Unsupervised Ensemble Learning Method for Nonlinear Dynamic State-Space Models. Neural Computation, Vol. 14, No. 11, 2002, pp. 2647-2692.

Ristaniemi, T., Raju, K., and Karhunen, J., Jammer Mitigation in DS-CDMA Array Systems Using Independent Component Analysis. In Proc. of the 2002 IEEE Int. Conf. on Communications (ICC2002), New York City, NY, USA, April 28 - May 2, 2002.

Valpola, H., Honkela, A., and Karhunen, J., An Ensemble Learning Approach to Nonlinear Dynamic Blind Source Separation Using State-Space Models. In Proc. of the Int. Joint Conf. on Neural Networks (IJCNN2002), Honolulu, Hawaii, USA, May 12-17, 2002, pp. 460-465. In the special invited session Advances on Independent Component Analysis.

Raju, K., Ristaniemi, T., Karhunen, J., and Oja, E., Suppression of Bit-Pulsed Jammer Signals in DS-CDMA Array Systems Using Independent Component Analysis. In Proc. of the 2002 IEEE Int. Symp. on Circuits and Systems (ISCAS2002), Phoenix, Arizona, USA, May 26-29, 2002, vol. I, pp. 189-192.

Ristaniemi, T., Raju, K., Karhunen, J., and Oja, E., Jammer Cancellation in DS-CDMA Arrays: Pre and Post Switching of ICA and RAKE. To appear in Proc. of the 2002 IEEE Workshop on Neural Networks for Signal Processing (NNSP02), Martigny, Switzerland, September 4-6, 2002, pp. 495-504.

2001

Hyvärinen, A., Karhunen, J., and Oja, E., Independent Component Analysis. J. Wiley 2001, 481+xxii pages. See the homepage of the book for more information and ordering instructions.

Valpola, H., Raiko, T., and Karhunen, J., Building Blocks for Hierarchical Latent Variable Models. In Proc. of the 3rd Int. Workshop on Independent Component Analysis and Signal Separation (ICA2001), San Diego, California, USA, December 9-13, 2001, pp. 710-715.

Valpola, H., Honkela, A., and Karhunen, J., Nonlinear Static and Dynamic Blind Source Separation Using Ensemble Learning. In Proc. of the Int. Joint Conf. on Neural Networks (IJCNN'01), July 2001, Washington D.C., USA, pp. 2750-2755. In the special invited session Nonparametric Information Theoretic Algorithms for Learning.

Karhunen, J., Nonlinear Independent Component Analysis. A review chapter in the book R. Everson and S. Roberts (Eds.), ICA: Principles and Practice. Cambridge University Press, Cambridge, UK, 2001, pp. 113-134.

2000

Karhunen, J., Malaroiu, S., and Ilmoniemi, M., Local Linear Independent Component Analysis Using Clustering.Int. Journal of Neural Systems, vol. 10, no. 6, November/December 2000, pp. 439-451.

Cristescu, R., Ristaniemi, T., Joutsensalo, J., and Karhunen, J., Blind Separation of Convolved Mixtures for CDMA Systems.In Proc. of the X European Signal Processing Conference (EUSIPCO 2000), Tampere, Finland, September 5-8, 2000, pp. 619-622.

Lappalainen, H., Honkela, A., Giannakopoulos, X., and Karhunen, J., Nonlinear Source Separation Using Ensemble Learning and MLP Networks.In Proc. of the Symposium 2000 on Adaptive Systems for Signal Processing, Communications, and Control (AS-SPCC), Lake Louise, Alberta, Canada, October 1-4, 2000, pp. 187-192.

Lappalainen, H., Giannakopoulos, X., Honkela, A., and Karhunen, J., Nonlinear Independent Component Analysis Using Ensemble Learning: Experiments and Discussion.In Proc. of the 2nd Int. Workshop on Independent Component Analysis and Blind Source Separation (ICA2000), Espoo, Finland, June 19-22, 2000, pp. 351-356.

Cristescu, R., Joutsensalo, J., Karhunen, J., and Oja, E., A Complexity Minimization Approach for Estimating Fading Gaussian Channel in CDMA Communications.In Proc. of the 2nd Int. Workshop on Independent Component Analysis and Blind Source Separation (ICA2000), Espoo, Finland, June 19-22, 2000, pp. 527-532.

Cristescu, R., Ristaniemi, T., Joutsensalo, J, and Karhunen, J., Delay Estimation in CDMA Communications Using a Fast ICA Algorithm.In Proc. of the 2nd Int. Workshop on Independent Component Analysis and Blind Source Separation (ICA2000), Espoo, Finland, June 19-22, 2000, pp. 105-110.

1999

Giannakopoulos, X., Karhunen, J., and Oja, E., An Experimental Comparison of Neural Algorithms for Independent Component Analysis and Blind Separation. Int. Journal of Neural Systems, vol. 9, no. 2, April 1999, pp. 99-114.

Karhunen, J., and Malaroiu, S., Locally Linear Independent Component Analysis.In Proc. of the Int. Joint Conf. on Neural Networks (IJCNN'99), July 1999, Washington D.C., USA, pp. 882-887.

Giannakopoulos, X., Karhunen, J., and Oja, E., An Experimental Comparison of Neural ICA Algorithms with Real-World Data.In Proc. of the Int. Joint Conf. on Neural Networks (IJCNN'99), July 1999, Washington D.C., USA, pp. 888-893.

Karhunen, J., and Malaroiu, S., Local Independent Component Analysis Using Clustering. In C. Jutten, J.-F. Cardoso, and P. Loubaton (Eds.), Proc. First Int. Workshop on Independent Component Analysis and Signal Separation (ICA'99), January 11 - 15, 1999, Aussois, France, pp. 43-48.

1998

Karhunen, J., Pajunen, P., and Oja, E., The Nonlinear PCA Criterion in Blind Source Separation: Relations with Other Approaches. Neurocomputing, vol. 22, November 1998, pp. 5-20.

Giannakopoulos, X., Karhunen, J., and Oja, E., An Experimental Comparison of Neural ICA Algorithms. In L. Niklasson, M. Boden, and T. Ziemke (Eds.), ICANN98 (Proc. 8th Int. Conf. on Artificial Neural Networks, Skovde, Sweden, September 2-4, 1998), Springer-Verlag, Berlin 1998, pp. 651-656.

1997

Pajunen, P., and Karhunen, J., A Maximum Likelihood Approach to Nonlinear Blind Source Separation. In W. Gerstner, M. Hasler, and J.-D. Nicoud (Eds.), Artificial Neural Networks - ICANN'97, Springer-Verlag, Berlin 1997, pp. 541-546.

Karhunen, J., Hyvärinen, A., Vigario, R., Hurri, J, and Oja, E., Applications of Neural Blind Source Separation to Signal and Image Processing. In Proc. IEEE 1997 Int. Conf. on Acoustics, Speech, and Signal Processing (ICASSP'97), April 21 - 24, 1997, Munich, Germany, pp. 131-134 (invited paper).

Karhunen, J., and Pajunen, P., Blind Source Separation Using Least-Squares Type Adaptive Algorithms. In Proc. IEEE 1997 Int. Conf. on Acoustics, Speech, and Signal Processing (ICASSP'97), April 21 - 24, 1997, Munich, Germany, pp. 3361-3364.

1996

Karhunen, J., Neural Approaches to Independent Component Analysis and Source Separation. In Proc. 4th European Symposium on Artificial Neural Networks (ESANN'96), April 24 - 26, 1996, Bruges, Belgium, pp. 249-266 (invited paper).

Older journal papers not available in electronic form here

Please note that you can find at least a few of these papers in the publisher's electronic databases of these journals.

Cichocki, A., Karhunen, J., Kasprzak, W., and Vigario, R., Neural Networks for Blind Separation with Unknown Number of Sources, Neurocomputing, vol. 24, nos. 1-3, February 1999, pp. 55-94. (Also published as Report A54, Helsinki Univ. of Tech., Publications in Computer and Information Science, September 1998.)

Pajunen, P., and Karhunen, J., Least-Squares Methods for Blind Source Separation Based on Nonlinear PCA. Int. Journal of Neural Systems, vol. 8, nos. 5 and 6, October/December 1998, pp. 601-612.

Karhunen, J., Cichocki, A., Kasprzak, W., and Pajunen, P., On Neural Blind Separation with Noise Suppression and Redundancy Reduction. Int. Journal of Neural Systems, vol. 8, no. 2, April 1997, pp. 219-237.

Karhunen, J., Oja, E., Wang, L., Vigario, R., and Joutsensalo, J., A Class of Neural Networks for Independent Component Analysis. IEEE Transactions on Neural Networks , vol. 8, no. 3, May 1997, pp. 486-504.

Oja, E., Karhunen, J., Hyvärinen, A., Vigario, R., and Hurri, J., Neural Independent Component Analysis - Approaches and Applications. In S.-I. Amari and N. Kasabov (Eds.), Brain-Like Computing and Intelligent Information Systems, Springer-Verlag, Singapore, 1997, pp. 167-188 (invited plenary paper at ICONIP'97).

Wang. L., and Karhunen, J., A Unified Neural Bigradient Algorithm for Robust PCA and MCA, Int. Journal of Neural Systems, vol. 7, no. 1, March 1996, pp. 53-67.

Karhunen, J., and Joutsensalo, J., Generalizations of Principal Component Analysis, Optimization Problems, and Neural Networks, Neural Networks, vol. 8, no. 4, 1995, pp. 549-562.

Karhunen, J., and Joutsensalo, J., Representation and Separation of Signals Using Nonlinear PCA Type Learning, Neural Networks, vol. 7, no. 1, 1994, pp. 113-127.

Karhunen, J., Stability of Oja's PCA Subspace Rule, Neural Computation, vol. 6, 1994, pp. 739-747.

Karhunen, J., and Joutsensalo, J., Sinusoidal Frequency Estimation by Signal Subspace Approximation, IEEE Trans. on Signal Processing, vol. 40, no. 12, December 1992, pp. 2961-2972.

Some photos from my album


With my golden retriever Nelli at a summer lodge in Punkaharju, Finland, in July 2004.

My family and dog at a summer lodge in Punkaharju, Finland, in July 2004.

With Dr. Kari Torkkola in the ICA99 workshop in January 1999 in Aussois, France.

With Profs. Erkki Oja (left) and Simon Haykin (middle) in January 2001 in Chamrousse, France.

With Fabian Theis (left) and Jaakko Särelä (middle) in December 2001 on Solana Beach, California, at the ICA2001 workshop.

My daughter Hanna and golden retriever puppy Nelli in winter 2002.