João Manuel de Freitas
Xavier
Assistant Professor, Electrical
Engineering Department
Instituto Superior Técnico
(IST)
Technical University of Lisbon, Portugal
Researcher at: Signal and Image
Processing Group, Institute
for Systems and Robotics (ISR), Lisbon, Portugal
Contact
information
Instituto
Sistemas e Robótica (ISR)
Instituto Superior Técnico (IST)
Av. Rovisco Pais
1049-001, Lisbon,
Portugal
Fax: (+351) 21 841 82 91
Phone: (+351) 21 841 82 96
Email: jxavier (@)
isr.ist.utl.pt
Publications
Teaching
- Nonlinear
Optimization (Spring 2010, Spring 2009, Autumn 2007, Autumn 2006,
Spring 2006)
- Optimization and
Algorithms (Autumn 2008, Autumn 2007, Autumn 2006, Autumn 2005)
- Signal
Processing (Autumn 2008, Autumn 2004)
- Nonlinear Signal
Processing (Spring 2008, Spring 2007, Spring 2005)
Current and former graduate students
- Pedro Guerreiro, PhD Thesis. Status: starts Sep. 2009
- Augusto Santos, PhD Thesis, co-supervision with Prof. José M. F. Moura
(CMU).
Status: ongoing
- Dusan Jakovetic, PhD Thesis, co-supervision with Prof. José M. F. Moura
(CMU).
Status: ongoing
- José Rodrigues, PhD Thesis, co-supervision with Prof. Takeo
Kanade
(CMU) and Prof.
Pedro
Aguiar (IST). Status: ongoing
- Dragana Bajovic, PhD Thesis, co-supervision with Prof. Bruno Sinopoli (CMU).
Status: ongoing
- João Mota, PhD. Thesis, co-supervision with Prof. Markus Pueschel (CMU)
and Prof. Pedro Aguiar
(IST).
Status: ongoing
- Ricardo
Ferreira, PhD. Thesis, co-supervision with Prof. João P.
Costeira
(IST). Status: ongoing
- Marko Beko,
PhD. Thesis: "Non-coherent
communication in multilple-antenna systems: receiver design, codebook
construction and capacity analysis". Status: finished, February 2008
- Paulo Lopes, MSc. Thesis: "Bayesian signal
reconstruction in wireless communication systems with spatial
diversity". Status: finished, 2004.
- Tiago Patrão, MSc. Thesis: "Tracking
a Mobile
Binary Source in Wireless Systems with Spatial Diversity". Status:
finished, 2003.
Publications
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Journal papers
2008
- P.
Aguiar, M. Stosic and J. Xavier,
"On
singular values of partially prescribed matrices", Linear Algebra and Its Applications,
vol. 429, no.8-9, pp. 2136-2145, October 2008
- M. Beko, J. Xavier
and V. Barroso, "Further results on the capacity
and error probability analysis of non-coherent MIMO systems in the low
SNR regime", IEEE
Transactions on Signal Processing, vol. 56, no. 7, pp.
2915-2930, July 2008
2007
- M. Beko, J. Xavier
and V. Barroso, "Non-coherent communication
in multiple-antenna systems: receiver design and codebook construction",
IEEE Transactions on Signal
Processing, vol. 55, no. 12, pp. 5703-5715, December 2007
- R. Oliveira, J. Xavier and J. P. Costeira, "Multi-View Correspondence by Enforcement of
Rigidity Constraints", Image
Vision and Computing Elsevier, vol. 25, no.6, pp.1008-1020, June
2007
2004
- P. Lopes, J. Xavier
and V. Barroso, "Blind Source Separation and Channel
Identification: Exploiting 2nd Order Statistics in Bayesian
Frameworks", Journal of the
Brazilian Telecommunications Society (JTBS), invited paper, 2004
2001
- J. Xavier, V.
Barroso and J. M. F. Moura, "Closed-form Correlative
Coding (CFC2) Blind Identification of MIMO Channels: Isometry Fitting
to Second-Order Statistics", IEEE
Transactions on Signal Processing, vol. 49, no. 5, pp.
1073-1086, May 2001
1999
- J. Xavier and V.
Barroso, "Blind
Source Separation, ISI Cancellation and Carrier Phase Recovey in SDMA
Systems for Mobile Communications'',
Wireless Personal Communications, special issue on Wireless
Broadband Communications, pp. 53-76, Kluwer Academic Publishers, June
1999
1998
- J. Xavier and V. Barroso, "Closed-form
Blind Channel Identification and Source Separation in SDMA Systems
through Correlative Coding'', IEEE
Journal on Selected Areas in Communications, vol. 16, no. 8, pp.
1506-1517, October 1998
- V. Barroso, J. Xavier and J. M. F. Moura, "Blind Array Channel
Division Multiple Access (AChDMA) for Mobile Communications",
IEEE Transactions on Signal Processing, vol. 46, pp. 737--752,
March 1998
Conference
papers
2009
- D.
Bajovic, B. Sinopoli and J.
Xavier, "Robust linear dimensionality
reduction for hypothesis testing with application to sensor selection", 47th Allerton Conference on Communication,
Control, and Computing, Illinois, USA, October 2009
- D.
Bajovic, B. Sinopoli and J.
Xavier, "Sensor selection for hypothesis
testing in wireless
sensor networks: a Kullback-Leibler based approach", 48th IEEE Conference on Decision and
Control - CDC'09,
Shangai, China, December 2009
- J.
Mota, J. Xavier, P. Aguiar and
M. Puschel, "Distributed algorithms for
basis pursuit", 2nd International Workshop on Signal
Processing with Adaptive Sparse Structured Representations,
Saint-Malo, France, April 2009
- M.
Paladini, A. del Bue, M. Stosic, M. Dodig, J. Xavier and L. Agapito,
"Factorization for non-rigid and articulated
structure using metric
projections", IEEE Computer Society Conference on
Computer Vision and Patter Recoginition - CVPR 2009, Miami,
Florida, USA, June 2009
- R.
Ferreira, J. Xavier and J. P.
Costeira,
"Reconstruction of isometrically deformable
flat surfaces in 3D from
multiple camera images", IEEE
International Conference on
Acoustics, Speech and Signal Processing - ICASSP'09, Taipei,
Taiwan, April 2009
- R.
Ferreira, J. Xavier and J. P.
Costeira,
"Shape from motion of nonrigid objects: the case
of isometrically deformable flat surfaces", British Machine Vision Conference - BMVC'09,
London, England, September 2009
- M.
Beko, J. Xavier and V.
Barroso, "Codebook design for communication in
spread and nonspread space-time block codes-based systems," 6th IEEE International Symposium on
Wireless Communication Systems - ISWCS'09, Siena-Tuscany, Italy,
September 2009
- P.
Ekim, J. Gomes, J. Xavier and
P. Oliveira,
"ML based sensor network localization and tracking: batch and
time-recursive approaches", 17th
European
Signal Processing Conference - EUSIPCO 2009, Glasgow, Scotland,
August 2009
- A. del
Bue, M. Stosic, M. Dodig and J. Xavier, "2D-3D
registration of deformable shapes with manifold projection", IEEE International
Conference on Image Processing - ICIP'09, Cairo, Egypt, November
2009
2008
- P.
Aguiar, J. Xavier and M.
Stosic, "Spectrally optimal factorization of
incomplete matrices", IEEE Computer Society Conference on
Computer Vision and Patter Recoginition - CVPR 2008, Anchorage,
Alaska, USA, June 2008
- J.
Rodrigues, P. Aguiar and J. Xavier,
"ANSIG: an analytic signature for
permutation-invariant two-dimensional shape representation", IEEE Computer Society Conference on
Computer Vision and Patter Recoginition - CVPR 2008, Anchorage,
Alaska, USA, June 2008
- M.
Beko, J. Xavier and V.
Barroso, "Low SNR analysis of the non-coherent
MIMO channel under arbitrary channel and noise correlation structures",
IEEE International Workshop on
Signal Processing Advances for Wireless Communicatoins - SPAWC'08,
Recife, Brazil, July 2008
- J.
Rodrigues, J. Xavier and P.
Aguiar, "Classification of unlabeled point sets
using ANSIG", IEEE International
Conference on Image Processing - ICIP'08, San Diego, California,
USA, October 2008
- P.
Aguiar, J. Xavier and M.
Stosic, "Globally optimal solution to exploit
rigidity when recovering structure from motion under occlusion", IEEE International Conference on Image
Processing - ICIP'08, San Diego, California, USA,
October 2008 [DoCoMo USA
Labs Innovative Paper Award]
- B.
Pires, J. M. F. Moura and J. Xavier,
"LASIC: a model invariant framework for
correspondence", IEEE
International Conference on Image Processing - ICIP'08, San
Diego, California, USA, October 2008
- N.
Monteiro, J. Gomes and J. Xavier,
"Detection of statistical periodicities in DNA by conflict and entropy
minimization methods", 16th European
Signal Processing Conference - EUSIPCO 2008, Lausanne,
Switzerland, August 2008
- J.
Seabra, J. Xavier and J.
Sanches, "Convex ultrasound image reconstruction with log-Euclidean
priors", 30th Annual International
Conference of the IEEE Engineering in Medicine and Biology Society -
EMBS'08, Vancouver, Canada, August 2008
- I.
Rodrigues, J. Xavier and J.
Sanches, "Fluorescence confocal microscopy imaging denoising with
photobleaching", 30th
Annual International Conference of the IEEE Engineering in Medicine and
Biology Society - EMBS'08, Vancouver, Canada, August 2008
- N.
Delgado, F. Nunes and J. Xavier,
"GNSS satellite selection for multiple-constellations using convex
geometry", 4th ESA Workshop on
Satellite Navigation User Equipment Technologies, December 2008
- N.
Delgado, F. Nunes and J. Xavier,
"A geometrical approach for maximum likelihood estimation of
multipath", Proceedings of The
Institute of Navigation - GNSS 2008, Savannah, September 2008
2007
2006
- M. Beko, J. Xavier
and V. Barroso, "Codebook design for the
non-coherent GLRT receiver and low SNR MIMO block fading channel", IEEE International Workshop on Signal
Processing Advances for Wireless Communications - SPAWC'06,
Cannes, France, July 2006
- J. Xavier and
Jonathan H. Manton, "On the
generalization of AR processes to Riemannian manifolds", IEEE International Conference on
Acoustics, Speech and Signal Processing - ICASSP'06, Toulouse,
France, May 2006
- M. Beko, J. Xavier
and V. Barroso, "Codebook design for
non-coherent communication in multiple-antenna systems", IEEE International Conference on
Acoustics, Speech and Signal Processing - ICASSP'06, Toulouse,
France, May 2006
- R. Ferreira, J. Xavier,
J. P. Costeira and V. Barroso, "Newton
method for Riemannian centroid computation in naturally reductive
homogeneous spaces", IEEE International Conference on
Acoustics, Speech and Signal Processing - ICASSP'06, Toulouse,
France, May 2006
- A. Alcocer, P. Oliveira, A. Pascoal and J. Xavier, "Maximum
likelihood attitude and position estimation from pseudo-range
measurements using geometric descent optimization", IEEE Conference on Decision and Control
(CDC'06), San Diego, CA, USA, December 2006
- A. Alcocer, P. Oliveira, A. Pascoal and J. Xavier,
"Estimation
of attitude and position from range only measurements using geometric
descent optimization on the special Euclidean group", 9th International Conference on
Information Fusion - FUSION 2006, Florence, Italy, July
2006
- R. Ferreira and J. Xavier,
"Hessian of the Riemannian squared-distance
function on connected locally symmetric spaces with applications", Controlo 2006, 7th Portuguese Conference
on Automatic Control , special session on control, optimization
and computation, September 2006
2005
- J. Xavier and V.
Barroso, "Intrinsic variance lower bound
(IVLB): an extension of the Cramer-Rao bound to Riemannian manifolds", IEEE International Conference on
Acoustics, Speech and Signal Processing - ICASSP'05, Philadelphia,
USA, May 2005
- R. Oliveira, J. P. Costeira and J. Xavier, "Contour point tracking by enforcement of
rigidity constraints", IEEE
International Conference on 3D Digital Imaging and Modeling -
3DIM 2005, Ottawa, Canada, June 2005
- R. Oliveira, J. P. Costeira and J. Xavier, "Optimal point correspondence through the
use of rank constraints", IEEE
Computer society Conference on Computer Vision and Pattern Recognition
- CVPR 2005, San Diego, USA,
June 2005
2004
- J. Xavier and V.
Barroso, "The Riemannian geometry of certain
parameter estimation problems with singular Fisher information matrices",
IEEE International
Conference on Acoustics, Speech and Signal Processing - ICASSP'04,
Montreal, Canada, May 2004
- J. Xavier and V.
Barroso, "Geodesic lower bound for parametric estimation with
constraints", IEEE
International Workshop on Signal Processing Advances for Wireless
Communications - SPAWC'04, Lisbon, Portugal, July 2004
2003
- T. Patrão, J.
Xavier,
V. Barroso, "An interior point algorithm for joint symbol detection and
multichannel acquisition in fast-fading narrowband channels", IEEE Signal Processing Workshop on
Signal Processing Advances in Wireless Communications - SPAWC'03, Rome, Italy, June 2003
- P. Lopes, J. Xavier,
V. Barroso, "Exploiting 2nd order statistics in Bayesian signal
reconstruction problems", IEEE
International Conference on Acoustics, Speech and Signal Processing
- ICASSP'03, Hong-Kong, April 2003
- T. Patrão, J.
Xavier, V. Barroso, "Blind symbol detection and channel
acquisition in fast-fading wireless systems with space diversity", IEEE International Conference on
Acoustics, Speech and Signal Processing - ICASSP'03,
Hong-Kong, April 2003
2002
- J. Xavier and V.
Barroso, "Intrinsic distance lower bound for unbiased estimators on
Riemannian manifolds", IEEE
International Conference on Acoustics, Speech and Signal Processing -
ICASSP'02, Orlando, May 2002
- J. Xavier, V.
Barroso, P. Lopes, "Blind source separation and channel identification:
exploiting 2nd-order statistics in Bayesian frameworks'',
International Telecommunications
Symposium - ITS'02,
Natal, Brazil, September 2002 [Conference
Best Paper Award]
- J. Xavier, V.
Barroso, T. Patrão, "Joint symbol detection and multi-channel
acquisition in fast-fading narrowband wireless environments'',
International Telecommunications
Symposium - ITS'02,
Natal, Brazil, September 2002
- J. Xavier, V.
Barroso, P. Lopes and T. Patrão, "Prewhitening of
mixing matrices: impact on the contraction of their probability mass
priors", IEEE
International Symposium on Information Theory, Lausanne,
Switzerland, 2002
2001
- J. Xavier, V.
Barroso, "Second-order blind MIMO channel identification based on
correlative coding: asymptotic performance analysis'",
IEEE International Symposium on
Information Theory, Washington, USA, June 2001
- J. Xavier and V.
Barroso, "Performance analysis of a second order statistics based
solution for the MIMO channel identification problem", IEEE International Conference on
Acoustics, Speech and Signal Processing - ICASSP'01, Salt
Lake City, USA, May 2001
- J. Xavier and V.
Barroso, "Blind identification of MIMO channels based on correlative
coding: performance analysis", IEEE
International Workshop on Signal Processing Advances for Wireless
Communications - SPAWC'01, Taoyuan, Taiwan, March 2001
2000
- J. Xavier and V.
Barroso, "A semi-blind maximum likelihood approach for resolving linear
convolutive mixtures", IEEE
International Conference on Acoustics, Speech and Signal Processing -
ICASSP'00, Istambul, Turkey, June 2000
- J. Xavier, V.
Barroso, "Blind identification on MIMO systems based on source
correlative filtering'", IEEE
International Symposium on Information Theory, Sorrento, Italy,
July 2000
- J. Xavier and V.
Barroso, "Semi-blind maximum likelihood separation of linear
convolutive mixtures", IEEE Workshop
on Statistical Signal and Array Processing - SSAP'00, Pennsylvania,
USA, August 2000
1999
- J. Xavier and V.
Barroso, "A channel order independent method for blind equalization of
MIMO systems", IEEE
International Conference on Acoustics, Speech and Signal Processing -
ICASSP'99, Phoenix, USA, March 1999
- J. Xavier and V.
Barroso, "Correlative coding approach for blind identification of MIMO
Systems", IEEE International
Workshop on Signal Processing Advances for Wireless Communications -
SPAWC'99, Annapolis, USA, May 1999
- J. Xavier and V.
Barroso, "Polyhedral concepts for deterministic blind separation of
binary sources'', Asilomar
Conference on Signals, Systems, and Computers, California, USA,
October 1999
- J. Xavier and V.
Barroso, "Blind identification of MIMO channels: a closed form
solution based on second-order statistics'', Asilomar Conference on Signals, Systems,
and Computers, California, USA, October 1999
- J. Xavier
and V. Barroso, "Joint symbol detection and multi-channel
acquisition in
fast-fading narrowband wireless environments'',
IEEE Global Telecommunications
Conference - GLOBECOM'99,
Rio de Janeiro, Brazil, December 1999
1998
- J. Xavier, V.
Barroso and J. M. F. Moura, "Closed-form blind identification of MIMO
systems", IEEE International Conference on
Acoustics, Speech and Signal Processing - ICASSP'98, Seattle,
USA, May 1998
- J. Xavier, V.
Barroso, "Low complexity blind minimum variance zero forcing
equalization of MIMO systems'", IEEE
International Symposium on Information Theory, Boston, USA,
August 1998
1997
- J. Xavier and V.
Barroso, "Blind SDMA with a signal space geometry matched algorithm",
IEEE International
Conference on Acoustics, Speech and Signal Processing - ICASSP'97,
Munique, Germany, April 1997
Book chapter
- V. Barroso, J. Xavier
and J. M. F. Moura, "Blind Channel Identification and Source Separation
in SDMA Systems'', Spatial Diversity and Source Estimation, in Antennas
Wireless Communications Handbook, Ed. Lal C. Godara, CRC Press, 2001
Technical
reports
- M. Dodig, M. Stosic and J.
Xavier, "On Minimizing a Quadratic Function
on Stiefel Manifolds", Technical Report, Signal and Image
Processing Group (SPIG), Institute for Systems and Robotics (ISR),
March 2009
- R. Ferreira, J. Xavier,
J. P. Costeira and V. Barroso , "Newton
Algorithms for Riemannian Distance Related Problems on Connected
Locally Symmetric Manifolds'', Technical Report, Signal and Image
Processing Group (SPIG), Institute for Systems and Robotics (ISR),
November 2008
Invited
presentation
PhD Thesis