La vertu d'un LA The virtue of an A - A fortunate hive

Ternary/trinary logic: bricks and trytes

2012-05-08T13:33:00.000-07:00

http://www.mortati.com/glusker/fowler/
The ternary calculating machine of Thomas Fowler

This short post is inspired by Igor Carron's The 2-bit Aggie weather station. Igor proposes us the three-valued (bbl) system for assessing weather conditions, with a brick put outside: brown, bright, left

If brick is dark brown, it's a sure sign that it's raining outside.
If the brick is bright, then it's sunny outside.
If the brick is not there anymore, it's a tornado.

The weird machine on the right is not a brick, and is better described in The ternary calculating machine of Thomas Fowler, IEEE Annals of the History of Computing, 2005, by Glusker, Hogan, and Vass.

Bender: Ahhh, what an awful dream. Ones and zeroes everywhere... and I thought I saw a two.
Fry: Don't worry, Bender: there's no such thing ...
Futurama

Among the very few scientific results i can grasp, a very few simple ones jump to my mind and keep me amazed:

the fact that the Wiles-Fermat theorem is almost trivial in polynomial ring (see Mason-Stothers ABC theorem, based on Wronskians for complex coefficients, showing that max(deg(A(a),deg(B(x),deg(C(x))) + 1 <= # roots (A(x)B(x)C(x))
Cantor's diagonal argument
statistical Stein's lemma and paradox, and some of it's signal processing applications (pdf)
the most beautiful Euler god-existing formula, involving constants pi, e, i, 1 and 0 (from utmost to least translucency)

van der Corput Lemma for oscillatory integrals
Pick's theorem relating inside, border points and area in lattice polygons
and, of course, a pair of others

The most radical one, pertaining to signal acquisition and representation, lies between the binary and the ternary systems: from bits to trits, from bytes to trytes. It states that the "most efficient" storing system is "e", from Euler's number, not to confuse with Mascheroni-Euler constant, gamma, (the one from the natural logarithm). I am quite surprised the binary system pervades so much the present digital world that this "fact" is quite often ignored. Indeed, when i try to gather some information on that topic, i generally do not remember where to start from. Which keywords (trit for "ternary digits" similar to bits for "binary digits", or "tryte" versus "byte" for the "words" themselves, trinary or ternary), what sources?

The basic idea is that, when trying to represent a number in concise or sparse from on d-digits (or number byte-width), one could choose the biggest b-base (or bit-depth, the number of symbols per "digit") for representation. In a similar way for signal or image processing, the sparsest base or frame for a specific signal or image has this signal or image data as a vector. The simplest idea comes from minimizing the product width x depth, or e(d,b) = = db, considered as a loss function.Let us compute it for all numbers from 0 to decimal N = 999999, in different numeral systems?

Decimal: b = 10, d = 6 = ceil(log(N+1)/log(b)), db = 60,
Binary: b = 2, d = 20, db = 40,
Ternary: b = 3, d = 13, db = 39,
Quaternary: b = 4, d = 10, db = 40.

Here we have a very local minimum at b =3. More generalized, the objective minimizes the loss function e(b) = b/log(b) (at WolframAlpha). The non-negative real minimum is "e". The two potential contenders for practical arithmetics, or even physics, are 2 (binary) or 3 (ternary), the two closest integers. It is easy to note that e(2) = 2.885... while e(3) = 2.731... and e(4) = 5.771 (compare to 2.718...). This confirms the preceding decimal/binary/ternary/quaternary local minimum at 3, 2 becoming second, the ternary numeral system, is closer to the absolute minimum. So we need to add 2 and 3 and propose a "Generalized"-) Euler formula:

and, more interesting, 3 should be more compact, even for three-valued logic in computer systems. The chapter Ternary computers: the setun and the setun 70, by N. P. Brusentov and J. R. Alvarez from Moscow state university (at Google books), indicates that this is an old story:

"It is known that the ternary arithmetic has essential advantages as compared with the binary one that is used in present-day computers. In connection with this Donald Knuth assumed that the replacement of "flip-flop" for "flip-flap-flop" one a "good" day will nevertheless happen [1]. Now, when the binary computers predominate, it is hard to believe in a reality of such assumption, but if it would happen not only the computer arithmetic, but the informatics on the whole would become most simple and most perfect. The third value (Aristotle named it snmbebhkoV – attendant) what is very actual but hidden in binary logic, will become obvious and direct manipulated. Ternary logic has better accordance with the Nature and human informal thinking [2]. Unfortunately, the modern researches of the multivalued (non-binary) logic are formal and are not associated with practical requests.A remarkable exclusion is the experience of creating the ternary computers "Setun" and "Setun 70" at Moscow State University [3,4,5,6]. This experience convincingly confirms practical preferences of ternary digital technique.

The design of small digital machine "Setun" (Setun is the little river which flows into the river "Moscow" near the University) was initiated by member of the academy of Sciences S. L. Sobolev at 1956. It was assumed to create small, inexpensive computer, simple in use and service for schools, research laboratories, design offices and for manufacture control. For such goal at the computer center of the University there was formed a group of young men (4 MS and 5 BA). The joint seminar for engineers and programmers was organized and S. L. Sobolev, K. A. Semendjev, M. R. Shura-Bura, I. S. Berezin were its permanent participants. The problems of optimization of computer architecture and technical realization were examined and the variants of future computer were discussed."

I especially like the flip-flap-flop mnemonic. "Perhaps the prettiest number system of all," writes Donald E. Knuth in The Art of Computer Programming, "is the balanced ternary notation."This reminds of the derivatives of position. Velocity and acceleration are well known, jerk is the 3rd. Jounce is sometimes given for the fourth derivative. Jounce is the rate of change of jerk, over the time. But some call the 4th, 5th and 6th derivatives "Snap, "Crackle" and "Pop" (as for the Rice Crispies, as for those interested in wavelets).

This story is summarized in Third Base at American Scientist, by Brian Hayes: (printer-friendly version, 2001).

"When base 2 is too small and base 10 is too big, base 3 is just right. "

It even recalls the following conjecture:
More than 20 years ago, Paul Erdös and Ronald L. Graham published a conjecture about the ternary representation of powers of 2. They observed that 2^2 and 2^8 can be written in ternary without any 2s (the ternary numerals are 11 and 100111 respectively). But every other positive power of 2 seems to have at least one 2 in its ternary expansion; in other words, no other power of 2 is a simple sum of powers of 3. Ilan Vardi of the Institut des hautes études scientifiques has searched up to 2^6973568802 without finding a counterexample, but the conjecture remains open.

Yet, even-though the first attempts have met difficulties (check out the early 1950 High Speed Computing Devices in djvu), people are still working towards ternary physical systems: Klein M., Mol J. A., Verduijn J., Levine R. D., et al. Ternary logic implemented on a single dopant atom field effect silicon transistor. APPLIED PHYSICS LETTERS. 2010; 96(4) (see Raphael Levine).

So yes Igor, this brick-like technology does (almost) exist. Or probably in a near future. Maybe it is not practical enough yet, or the world is not ready for that. A while ago (30 years), i learned how to count in binary with my fingers (thanks to a mormon American, CF, thinking of you), and we have three phalanges, so i can easily switch. But the ternary politic system still does not yet exist in France.

Plagiarism: everything but the title

2012-04-30T04:11:00.000-07:00

Cannot remember the origin of this picture (pdf)

[Post originated from Grégory Favre news on excellent EPFL Infodoc mailing list]
The pressure of publication pushes back the frontiers of laziness. Where a sole change in title allows a paper pass through reviews (if there are any reviews in this case, look at Nuit Blanche on peer review). The most interesting example i had seen seen so far was a paper i reviewed on nonsubsampled contourlets. Its content had about 60% overlap with a more standard and authoritative paper on the topic. A big difference resided in the typeset: the text was written with word (instead of LaTeX), the figures were drawn in Word too (instead of Xfig). I hereby provide a little excerpt, so you can check the subtle differences:

Original paper: 2) Nonsubsampled Directional Filter Bank (NSDFB): The directional filter bank of Bamberger and Smith [18] is constructed by combining critically-sampled two-channel fan filter banks and resampling operations. The result is a tree-structured filter bank that splits the 2-D frequency plane into directional wedges. A shift-invariant directional expansion is obtained with a nonsubsampled DFB (NSDFB). The NSDFB is constructed by eliminating the downsamplers and upsamplers in the DFB (see also [20]). This is done by switching off the downsamplers/upsamplers in each two-channel filter bank in the DFB tree structure and upsampling the filters accordingly. This results in a tree composed of two-channel NSFBs. Fig. 3 illustrates a four channel decomposition.

Submitted paper: b: Nonsubsampled Directional Filter Bank (NSDFB) The directional filter bank of Bamberger and Smith [14] is constructed by combining critically-sampled two-channel fan filter banks and resampling operations. The result is a tree-structured filter bank that splits the 2-D frequency plane into directional wedges. A shift-invariant directional expansion is obtained with a nonsubsampled DFB (NSDFB). The NSDFB is constructed by eliminating the downsamplers and upsamplers in the DFB. This is done by switching off the downsamplers/upsamplers in each two-channel filter bank in the DFB tree structure and upsampling the filters accordingly. This results in a tree composed of two-channel Nonsubsampled Filter Banks (NSFB). Fig. 3 illustrates a four channel decomposition.

But i am unfair: the reference list was quite different. Interestingly, to the genuine honesty of the authors, the partly copied paper was even cited the original paper: A. L. Cunha, J. Zhou, M. N. Do. The nonsubsampled contourlet transform: Theory, design, and applications. IEEE Trans. on Image processing, 2006, 15(10): 3089-3101.

I am not sure this recent trend deserves as much praise as Jorge Luis Borges short story: Pierre Menard, autor del Quijote. The story narrates 20th century writer Pierre Ménard's efforts to truly re-create Cervantes' Don Quixote, beyond a mere translation, in the 17th century Spanish, sparking thoughts on authorship, imitation and appropriation (well, 60% of my words are similar to Wikipedia page ;) There are worse artifacts than copy indeed: "Mirrors and fatherhood are abominable because they multiply it [human kind] and extend it.(Les miroirs et la copulation sont abominables car ils multiplient le nombre des hommes)" (J. L. Borges).

The recent example does some genuine editing: the title is partly new (SOA is mainly expanded), acknowledgments have been deleted, and the references cut to item 21. That's a Catch 22.

Interacting with the SOA-Based Internet of Things: Discovery, Query, Selection, and On-Demand Provisioning of Web Services, IEEE TRANSACTIONS ON SERVICES COMPUTING, 2010: http://www.vs.inf.ethz.ch/res/papers/dguinard-intera-2010.pdf
Service Oriented Architecture-Based Internet of Things: Discovery, Query, Selection, and On-Demand Provisioning of Web Services, International Journal of Computer Science and Telecommunications, 2012 http://www.ijcst.org/Volume3/Issue1/p7_3_1.pdf ([EDIT] funnily, the paper does not seen to be accessible anymore since the beginning of this post, still there is a Google Trace, and i have saved it on my drive, in case i'd like to publish a paper on SOA-based Internet of Things in a near future)

Click on images for a larger view.I just discover there is a Wikipedia page in Scientific plagiarism in India.

Conference: Fixing mathematical education

2012-04-26T15:13:00.000-07:00

[Permission to link to author slides is being asked. Stay tuned, but do not expect too much] Meanwhile, check out Simon Leys (aka Pierre Rickmans) "Le studio de l'inutilité" (or The Hall of uselessness), with a special attention to Leys' talk on 8 Nov. 2005 at l'Université catholique de Louvain, with its nice quote to Flaubert: "I have always tired to live in an ivory tower; but a tide of shit is beating at its walls, threatening to undermine it."

"Modeling is a life skill" (Solomon Garfunkel)

"To be able to use maths at a certain level, it is necessary to learn it at the next level" (Alexandre Borovik)

On April 4h, 2012, a meeting held in IPH, Paris. Under the motto: How to fix our math education (Comment réparer l’enseignement des mathématiques ?). The main incentive was Solomon GARFUNKEL (COMAP Inc., Boston) and David MUMFORD (Brown University) paper "How to fix our math education", New York Times, August 28th, 2011. The paper was translated in french in Le Monde (14 septembre 2011) by Jean-Michel Kantor under the same title: Comment réparer l’enseignement des mathématiques ?. Motivated by some prominence of mathematics, and bad results of France in PISA benchmarks, the conference aimed at answering the following questions:

does our education system answer the needs of newly opened areas in the scientific and technical realms?
how do we can train citizens on the present century?

Two talks were given by Sol Garfunkel (What Mathematics Do Educated Citizens Need To Know?) and Alexandre Borovik (What do children learn when we teach them mathematics?), chaired and translated by Jean-Michel Kantor.

Both conferences were profound, lively, though provoking and entertaining, in a different style. Sol explained the motivations behind the NYT paper: the U.S. education was local to the extreme, with highly varying levels between states, counties, and even neighborhoods. Two great 4-letter sticker acronyms (NCLB: no child left behind, under G. Bush, and RTTT: race to the top, under B. Obama) have tried, and are trying, respectively, to change this local situation, by establishing nation-wide standards. The resulting goals reside in showing that mathematics are honestly (in the meaning of the honnête homme) useful and in ensuring the availability, in the future, of mathematicians and scientists. Mathematics provide a greater ability to understand (or model) the world: "Modeling is a life skill" (SG). Sol reminded that cellphones and MRI are as much as engineering as maths. He also pointed out how operational research, computers, statistics used to belong to math departments, and have now grown into self-owned fields. He advocated the use of real-life examples graphs through mail delivery, Voronoi cells and bisectors via *** pizza delivery from Bengladesh call centers and rain falls in Colorado. Indeed, teachers tend to provide students with answers for questions they do not ask for. Looks like the following quote, inspired by Plotin, attributed to J. Lacan: « l’amour est donner ce qu’on n’a pas à quelqu’un qui n’en veut pas ». So students (and forthcoming adults) need an ability to estimate. Maths are a necessity for survival.

Alexandre Borovik drove a useful comparison between rhythm-impaired people (because of a drunk and noisy music teacher) and people who could not understand maths. Both are survivors. He considers (following Heinrich Neuhaus "the art of piano playing") that learning is an accumulation of neurological damage, reaching a threshold level. Some of us as only survivors. In a sort of Pareto-law, he tells that 95% of the population has no ideas on how 95% of the everyday stuff works, as a follow-on to the division of labor (Adam Smith, Frederick W. Taylor). He suggests re-branding maths into a tool for personal development and spiritual enhancement. Like music, not a profession, but a personal life-style. Teachers should thus be bound to the Hippocratic oath: do not arm. Which other school (mathematics including computer science) teaches "substitution of terms", at work in simple Excel sheets that provoke bracket overload (or in French "surcharge parenthétique") when three opening brackets and cell-depending operators confuse most people. Maths should be both interesting AND difficult, remember the "Law of excessive learning of mathematics": "to be able to use maths at a certain level, it is necessary to learn it at the next level".

He finally suggests teaching math bits at certain ages: maybe basic algebraic structures at 6-9 when kids are natural question-asking machines, leaving set-theoretic abstractions for teen-age, where sex hormones lead some appeal to pure idealities.

Additional lectures:

Sol Garfunkel 10 Improving education will require teamwork
Algebra: In Simplest Terms - Mathematical Induction
Alexandre Borovik: Book in progress: Shadows of the Truth: metamathematics of Elementary Mathematics (pdf)

Why Should Anyone Study Mathematics, Timothy S. Norfolk
What Mathematics do Elementary Education Teachers need to know?, Bret Benesh

Todays bonus: Project Gutenberg: Mathematics' Bookshelf: classic mathematics books typeset with latex, with for instance Henri Poincaré, Science and hypothesis.

Hyperbolets (on WITS: Where is the Starlet)

2012-04-22T06:34:00.002-07:00

A new conference is born: UCCV 2013, The 1st IEEE Workshop on User-Centred Computer Vision, due in Florida, Tampa. on January 2013. It has been added to SIVA Conferences.

While the shearlets are enjoying some spread (cf. Shearlets from MIA 2012 or this paper), some of their contributors are involved in hyperbolets, or hyperbolic wavelets, closely related cousins. Here they are (as on WITS: where is the Starlet):

Hyperbolets

In short:	An example of multi-composite wavelets with hyperbolic scaling law
Etymology:	From the hyperbola (wiki entry), with a potential reference (article no available on 2011/05/26) to the parabolic scaling law of the shearlets
Origin:	Glenn R. Easley, Demetrio Labate, Vishal M. Patel: Multi-composite wavelet estimation, Proceedings of SPIE Volume 8138, Wavelets and Sparsity XIV, Aug. 2011 (local copy) Abstract: In this work, we present a new approach to image denoising by using a general representation known as wavelets with composite dilations. These representations allow for waveforms to be defined not only at various scales and locations but also at various orientations. For this talk, we present many new representations such as hyperbolets and propose combining multiple estimates from various representations to form a unique denoised image. In particular, we can take advantage of different representations to sparsely represent important features such as edges and texture independently and then use these estimates to derive an improved estimate. The hyperbolet construction is further refined in: G. R. Easley, D. Labate and V. M. Patel, Hyperbolic shearlets, IEEE International Conference on Image Processing (ICIP), Orlando, FL, 2012, submitted (local copy) G. R. Easley, D. Labate, and V. M. Patel, Directional multiscale processing of images using wavelets with composite dilations, submitted 2011 (local copy)
Contributors:	Glenn R. Easley (no personal page), Demetrio Labate, Vishal M. Patel
Some properties:	Tiling of the frequency domain associated with an hyperbolic system of wavelets with composite dilations. Closely related to shearlets
Anecdote:
Usage:
See also:	The above work might be related to Glenn R. Easley, Demetrio Labate: Critically Sampled Wavelets with Composite Dilations (local copy), preprint, 2011, which develops intersting critically sampled directional wavelet schemes (DWTShear, CShear, QDWTShear)
Comments:

Dry signal processing

2012-04-18T16:00:00.000-07:00

Signal Processing is very akin to dry fruits: this is the very art of transforming .DAT 's in .FIG 's
https://twitter.com/#!/laurentduval/status/192746543349108736

Only that? Sure.

WITS: Shearlets from MIA 2012

2012-03-06T15:34:00.000-08:00

At the wonderful MIA 2012 (hey Gabriel, did i tell you how that was great?), two talks have been devoted to shearlets (Gitta Kutyniok, Gabriele Steidl), yet another geometric multiscale representation for images. And a brand new Matlab toolbox from Gabriele Steidl group named FFST (fast finite shearlet transform) and developed by Sören Haüser has been announced.

Shearlet-Zerlegung eines Auges.© Gitta Kutyniok

A good opportunity to update a little corner of WITS: Where is the Starlet, which was beginning to grow a few webs. Mmh, look like some familiar frequency domain partitioning... And now for something completely different: number 1, the shearlet... the shearlet! (Monty Python inside)

Shearlets

In short:	Non-separable wavelets built out of parabolic scaling, shear, and translation operations
Etymology:	From shear, a sheer distorsion
Origin:	Labate, Demetrio and Lim, W-Q. and Kutyniok, Gitta and Weiss Guido, Sparse multidimensional representation using shearlets (local copy) A handful lot of papers is available here: shearlet papers. A first overview is given in Shearlets. The First Five Year (Oberwolfach Report, 2010, local copy).

Some properties:	Unlike curvelets, shearlets form an affine system with a single generating mother shearlet function parameterized by a scaling, a shear, and a translation parameter. Provides the same approximation properties as curvelets, albeit with a different directional sensitivity. Exist in band-limited or compact support flavors. Possess natural, canonical smoothness spaces, called shearlet coorbit spaces, similar to Besov spaces for wavelets. Apparently extend to arbitrary any dimensions.

Usage:	Image denoising, restoration, morphological component analysis
See also:	The shearlet website, recently updated with ShearLab (... a rationally designed digital shearlet transform) For discrete implementation, there exists for instance a Digital Shearlet Transforms or Development of a Digital Shearlet Transform Based on Pseudo-Polar FFT. Shearlet Matlab toolboxes are available at ShearLab matlab toolboxes, local shearlet toolbox by G. Easley and FSST: ShearLab-1.1 (Implementation based on Cartesian Grids) (direct link ) ShearLab-PPFT-1.0 (Implementation based on Pseudo-Polar Grids) (direct link ) The recent (2012) FFST - Fast Finite Shearlet Transform by Sören Häuser The FFST package provides a fast implementation of the Finite Shearlet Transform. Following the the path via the continuous shearlet transform, its counterpart on cones and finally its discretization on the full grid we obtain the translation invariant discrete shearlet transform. Our discrete shearlet transform can be efficiently computed by the fast Fourier transform (FFT). The discrete shearlets constitute a Parseval frame of the finite Euclidean space such that the inversion of the shearlet transform can be simply done by applying the adjoint transform. with a Fast Finite Shearlet Transform tutorial (local copy)
Comments:	Potential a hard competitor, for years to come, to the quite oversold curvelets (IMHOlet: In My (little) Humble Opinion)

De la donnée à l'information : chimie et procédés

2012-03-06T14:20:00.000-08:00

Un peu de publicité pour cette Journée scientifique et Professionnelle au titre alléchant : "de la donnée à l’information : Comment accroître la productivité et mieux exploiter les résultats de mesure ?"

Nancy, 31 mai 2012, ENSIC, 1, rue Grandville F-54001 Nancy, (manifestation, initialement prévue le 12 janvier 2012)

Cette "Journée Scientifique et Professionnelle" intitulée : "De la donnée à l'information: Comment accroître la productivité et mieux exploiter les résultats de mesure" est organisée par le Laboratoire Réaction et Génie des Procédés (LRGP) de l'ENSIC et la Société des Experts Chimistes de France (SECF). Cette manifestation s’adresse aux chercheurs (académiques et industriels) et aux autres acteurs de l’industrie (exploitants et analystes). Elle a pour objectif de présenter l’état de l’art et les technologies émergentes concernant:

l’expérimentation haut débit,
les capteurs,
et les systèmes de traitement et de gestion de l’information.

Une exposition de fournisseurs présentant leurs équipements (matériels/logiciels), sera présentée en plus des conférences lors de cette journée.

Programme et inscription :
9h – 9h30: Accueil à l’ENSIC Nancy
9h30 - 10h : Introduction : Allocutions d’ouverture - Présentation de la journée, de l’ENSIC et de
ses laboratoires
10h - 11h30: L’expérimentation haut débit : génération de données et amélioration de la
productivité

Qu’est-ce que l’expérimentation haut débit ? Matthieu GUIRARDEL. (Laboratoire du Futur P.G. de Gennes UM 5258. Pessac)
La microfluidique: Intégration et parallélisation, un changement de paradigme pour les méthodes analytiques. Jean-Louis VIOVY. Institut Curie. Groupe Macromolécules et Microsystèmes en Biologie et Médecine (MMBM)
L’expérimentation haut débit : génération de données et amélioration de la productivité au travers des exemples de l'industrie et de la recherche académique'', Amira ABOU-HAMDAN, CHEMSPEED TECHNOLOGY AG (Augst, Suisse)

11h30 -12h : Brèves présentations des sociétés présentes à l’exposition et de leurs activités
12h -13h30 : Repas-buffet dans locaux de l’exposition
13h30 - 14h30 : Acquisition de l’information : les capteurs

Capteurs émergents, intervenant à préciser
Quelques applications des capteurs : Marie-Noëlle PONS (ENSIC Nancy)

14h30 – 15h30 : Pause et visite de l’exposition
15h30 - 17h : Exploitation de l’information / Gestion de l’information / Modélisation.

"Chimiométrie : bases et applications en agroalimentaire, en chimie et en pharmacie", Sylvie ROUSSEL (ONDALYS, Montpellier)
Algorithmes et chimie : interactions entre analyses physico-chimiques et traitement des signaux, Laurent DUVAL (IFPEN)
Les LIMS : nouvelles tendances, Éric DEWITTE (MB Développement)

17h - 17h15 : Conclusions - Synthèse de la journée : Cornélius SCHRAUWEN. (ENSIC – LRGP)

Autres sources :

Et je refais un brin de publicité pour Call for papers: Dossier, Special issue on Advances in signal and image processing for physico-chemical analysis [physical or analytical chemistry], la deadline étant étendue en avril

Call for papers: Advances in signal and image processing for physico-chemical analysis

2012-01-10T14:35:00.000-08:00

(CfP: Deadline extension) Looking for new frontiers in signal and image processing applications in physico-chemical analysis? Have compressive sensing results for mass spectrometry? Got improvements on the Savitsky-Golay filter? Consider the following call for contributions.

Call for papers: Dossier, Special issue on Advances in signal and image processing for physico-chemical analysis (pdf)

Deadlines : Final manuscript: February 17th, 2012

Oil & Gas Science and Technology - Revue d'IFP Energies Nouvelles (online journal)

WikiCfP: OGST-SIP-PCA

With the advent of more affordable, higher resolution or innovative data acquisition techniques (for instance hyphenated instrumentation such as two-dimensional chromatography), the need for advanced signal and image processing tools has grown in physico-chemical analysis, together with the quantity and complexity of acquired measurements. Either with mono- (signals) or two-dimensional (from hyphenated techniques to standard images) data, processing generally aims at improving quality and at providing more precise quantitative assessment of measurements of materials and products, to yield insight or access to information, chemical properties, reactive dynamics or textural properties, to name a few (for instance). Although chemometrics embrace from experimental design to calibration, more interplay between physico-chemical analysis and generic signal and image processing is believed to strengthen the two disciplines. Indeed, although they strongly differ in background and vocabulary, both specialities share similar values of best practice in carrying out identifications and comprehensive characterizations, albethey of samples or of numerical data.
The present call for papers aims at gathering contributions on recent progresses performed and emerging trends concerning (but not limited) to:

1D and 2D acquisition, sparse sampling (compressive sensing), modulation/demodulation, compression, background/baseline/trend estimation, enhancement, integration, smoothing and filtering, denoising, differentiation, detection, deconvolution and source separation, resolution improvement, peak or curve fitting and matching, clustering, segmentation, multiresolution analysis (wavelets), mathematical morphology, calibration, multivariate curve resolution, property prediction, regression, data mining, tomography, visualization,

pertaining to the improvement of physico-chemical analysis techniques, including (not exclusively):

(high-performance) gas, liquid or ion chromatography; gel electrophoresis; diode array detector; Ultraviolet (UV), visible, Infrared (NIR, FIR), Raman or Nuclear Magnetic Resonance (NMR) spectroscopy, X-ray diffraction (XRD), X-Ray Absorption (EXAFS, XANES), mass spectrometry; photoacoustic spectroscopy (PAS); porosimetry; hyphenated techniques (GCxGC); electron microscopy (SEM, TEM),

in the following proposed domains (not exclusively):

catalysis, chemical engineering, oil and gas production, refining processes, petrochemicals, and other sources of energy, in particular alternative energies with a view to sustainable development.

Provisional deadlines:

Statement of intent: January 31st, 2012
Submission of final manuscript: February 17th, 2012
Publication: 2nd semester 2012

Refering links:
Thierry Gallouët Igor Carron at Nuit Blanche in Around the blogs in 80 hours, Harris Georgiou, GdR ISIS

More details:
http://tinyurl.com/ogst-signal-chemical-analysis
http://www.laurent-duval.eu/lcd-cfp-ogst-2012-call-for-papers-signal-image-processing-physico-chemical-analysis.html

Computer tools for buddies

2011-12-26T14:25:00.000-08:00

Amongst a novena of virtual life savers on computers (under Windows XP or seven of course, everything is great with MacOS or Linux), we have the following. If you just want to pick one, pick Everything! Friends keep on thanking me for that.

file finding via Everything, a ligth-weight freeware to find files and directories with wildcards or regular expressions (then you can easily disable Windows *.* indexing and save hassle, space and time). It revolutionized my way of naming AND storing files (project management, bibliographic references files, mainly)
USB port cleaning with DriveCleanup when after some use, your usb keys and drives do not mount nicely
stuff and idea organizing via mindmapping software, for instance FreeMind or FreePlane
task organizing and GTD (getting things done) via ToDO list
note taking (simple and yet, simple) via The Guide, or maybe TreeSheet
word synonyming via Wordnet
communicating via Skype on usb key (its install is forbidden on my work laptop): copy some new Skype.exe file (from any local installation) to any directory (SkypePortable) on your USB Drive; in that directory create a directory named "Data", above create a file (with a text pad like context or notepad++) called "skype.bat" with command line "skype.exe /datapath:"Data" /removable", that you can launch instead of skype.exe (7zip archive here for Skype version 5.9.0.114). For DIY versions: http://www.gruups.com/usbskype/ or Skype Portable or TheUberOverLord Formally Install Skype to USB Drive Only
security via Keypass, (open source version), to keep and propose password for management,
podcasting via Ziepod (or Juice).

That's my Xmas gift for virtual life friends, for what it's worth. Update from The turn of a friendly card - Train numbering trick. What else?

Chuck Norris keyboard fact

2011-12-12T08:32:00.000-08:00

In a long lasting trend of jokes on popular antonyms, Chuck Norris facts as well as Car Friedrich Gauss facts (The greatest mathematician since antiquity or Gauss facts thus far, see Carl Friedrich Gauss Facts), i would like to share this one (shared on Facebook or Twitter):

Chuck Norris just sucks. If he were as smart and strong it's claimed, he'd just come here and slam my head on the keyboardasdmsdfvmwefjkmasd [space] [space] [space] [space] [space]

Okay, i haven't posted nothing for a month, let's be serious for a while. :

ChucK: audio programming language (Strongly-timed, Concurrent, and On-the-fly Audio Programming Language)
ChucK is a new (and developing) audio programming language for real-time synthesis, composition, performance, and now, analysis - fully supported on MacOS X, Windows, and Linux. ChucK presents a new time-based, concurrent programming model that's highly precise and expressive (we call this strongly-timed), as well as dynamic control rates, and the ability to add and modify code on-the-fly. In addition, ChucK supports MIDI, OSC, HID device, and multi-channel audio. It's fun and easy to learn, and offers composers, researchers, and performers a powerful programming tool for building and experimenting with complex audio synthesis/analysis programs, and real-time interactive control.

with something to do with keyboards...

And now for something completely different:

(Johann) Carl Friedrich Gauss is radical (with respect to the "roots", as in Jimmy Cliff's Roots radical) in signal processing for many reasons, and mainly for the possible invention of what is known today as the FFT or Fast Fourier transform (Cooley–Tukey FFT algorithm). You may just quote wikipedia:

This algorithm, including its recursive application, was invented around 1805 by Carl Friedrich Gauss, who used it to interpolate the trajectories of the asteroids Pallas and Juno, but his work was not widely recognized (being published only posthumously and in neo-Latin).[1][2] Gauss did not analyze the asymptotic computational time, however. Various limited forms were also rediscovered several times throughout the 19th and early 20th centuries.

or refer to Gauss and the history of the fast Fourier transform, by Michael T. Heideman, Don H. Johnson and C. Sidney Burrus as appeared behind paywalls Archive for History of Exact Sciences, Volume 34, Number 3, 265-277, DOI: 10.1007/BF00348431 or IEEE Acoustics, speech and signal processing Magazine, October 1984. A downloadable copy can be found here. The FFT has profound applied connections with early oil industry: some say (though i am not able to provide an online reference yet) that FFT algorithms were known to oil industry years before Cooley and Tukey's (1965), and they did not even bother patent it (because patents are a way to disclose, and sometimes secret is just simpler for protecting). Other early insights on connections between electrical engineering and geophysics are to be found in Oral-History with Enders Robinson who states two main problems, related to some (yet unknown) inverse problem equation:

Gauss primes

They followed the new group, but they were also very concerned with their own special problems. Their problem was 1)to collect data, then 2) produce a map of where to drill the oil well.

So what about an even stronger Gauss fact? Well, Gauss can beat Stalin, Poutin AND Medvedev. As read on
За нормальное распределение (in french, Images des mathématiques La loi normale de Gauss s’invite dans les manifs. Carl Friedrich Gauss depicted with goat's horns? No way, since Gauss is often described as the fox of mathematics, for his abilities to hide his (mathematical proofs') tracks on the sand (or snow) with his tail.

Abel said, `He is like the fox, who effaces his tracks in the sand with his tail'. Gauss, in defense of his style, said, `no self-respecting architect leaves the scaffolding in place after completing the building'.

Quoted in Startribune:

"Obviously, he doesn't agree with Gauss," one commenter wrote disdainfully, referring to pioneering mathematician Carl Friedrich Gauss, who lived 200 years ago. Disenchanted Russians argue that United Russia's reported election results are so improbable as to violate Gauss' groundbreaking work on statistics.

One slogan: "we beleive in Gauss, not in Churov". Vladimir Churov is the president of Central Election Commission of Russia, but apparently breeches the central limit theorem. So as Stalin used to say: Gauss, how many divisions? Let's look at Gauss integers (left image). Chuck Norris vs. Gauss? Battle's ongoing.

Update on Pixel shaker (aka Frédéric Morain-Nicolier): Carl Gauss strongly refuted Chuck Norris conjecture (get a snapshot now, this infringes standard arithmetics) that 1550 < 6450. A century before.

Unary Day

2011-11-11T14:37:00.001-08:00

I wouldn't have spent this special day with unary sequence 11h1111s at 11/11/11 without a terrible pun, mentioning it as the anniversary of Attila, since it's "an invasion of the Huns" ("huns" for "ones", uttered with an awful accent); even made a Facebook page for that: Attila Fest. Not proud :) Yet this dull (not in the Ramanujan sense) sequence reminded me of two nice formula for the golden ratio (aka $\phi$, or the divine proportion): one rational, one radical. So it seems $\phi$ could be tamed (or approched) quite easily. Indeed, it is one of the simplest non-rational numbers, as a root of a basic equation of degree 2. Thus, far from being transcendental. Surprisingly, $\phi$ bears some kind of transcendence (in the religious sense) as it is, somehow, beyond the grasp of the human mind, meaning it cannot be approched easily in a "rational" way, i.e. worse that any other number, as stated in a theorem by Adolf Hurwitz (1856-1919). In the following formula, there exist infinitely many $m$ and $n$ for any irrational $\xi$, and the constant $\sqrt(5)$ cannot be improved, due to $\phi$.

The radical formula for $\phi$ above is the key: with divisions by ones, denominators increase very very slow. Contrary to common knowledge (in Age of Empires) that Huns are faster. Thus being, in think i'd better go back to a paper on applications of unary filters, instead of making dull puns.

Advances in signal and image processing for physico-chemical analysis

2011-11-04T15:22:00.000-07:00

Looking for new frontiers in signal and image processing applications in chemical related analysis? Consider the following call for contributions.

Call for papers: Dossier, Special issue on Advances in signal and image processing for physico-chemical analysis (pdf)

Deadlines - Intent: December 12th, 2011 / Final manuscript: January 8th, 2012

Oil & Gas Science and Technology - Revue d'IFP Energies Nouvelles (online journal)

1D and 2D acquisition, sparse sampling (compressive sensing), modulation/demodulation, compression, background/baseline/trend estimation, enhancement, integration, smoothing and filtering, denoising, differentiation, detection, deconvolution and source separation, resolution improvement, peak or curve fitting and matching, clustering, segmentation, multiresolution analysis, mathematical morphology, calibration, multivariate curve resolution, property prediction, regression, data mining, tomography, visualization,

pertaining to the improvement of physico-chemical analysis techniques, including (not exclusively):

(high-performance) gas, liquid or ion chromatography; gel electrophoresis; diode array detector; Ultraviolet (UV), visible, Infrared (NIR, FIR), Raman or Nuclear Magnetic Resonance (NMR) spectroscopy, X-ray diffraction (XRD), X-Ray Absorption (EXAFS, XANES), mass spectrometry; photoacoustic spectroscopy (PAS); porosimetry; hyphenated techniques; electron microscopy (SEM, TEM),

in the following proposed domains:

catalysis, chemical engineering, oil and gas production, refining processes, petrochemicals, and other sources of energy, in particular alternative energies with a view to sustainable development.

Provisional deadlines:

Statement of intent: December 12th, 2011
Submission of final manuscript: January 8th, 2012
Publication: 2nd semester 2012

Opinion on Melancholia

2011-08-15T11:49:00.000-07:00

Lars von Trier has recently proposed to the audience the Cannes awarded movie Melancholia. As for the brunette and the blonde sisters (one organized and the other erratic), as for the two planets (Earth and Mechancolia) featured in the movie (one rotating predictively for ever around the sun, the other wobbling to its final destination), the movie has attracted two-pole reviews, either good or bad (in random order). Melancholia, as a science-fiction movie (is it?), dwells on a the line that joins Stanley Kubrick's 2001 and Andrei Tarkovsky's Solaris. On very projective line, between "zero and infinity" (le zéro et l'infini), which translates into French Darkness at noon by Arthur Koestler.

Von Trier's Mechancolia of course reminds of Albrecht Dürer's (the painter, not the insect - see Monty Python's in three languages) Melencolia I ou La Melencolia. The engraving has suffered many interpretations, with all its symbolic details (magic square, sphere, truncated rhombohedron...) combined with the standard inference of "Melencolia I" or "Melencholia Imaginativa", in which "imagination" predominates over "mind" or "reason".

Beautiful picture, ear-deafening Wagner music, fine directed, the film would only need some direction. After clear-cut editing, it would probably make a nice desktop wallpaper.

Oh yes, i forgot to tell you (for those who have an eye for finest details, these words are from another SicFi movie Dune), the Signal Processing: Special issue on Advances in Multirate Filter Bank Structures and Multiscale Representations is out: at ScienceDirect (Signal Processing, Volume 91, Issue 12), here in a blog post or on a separate page. Feel like melancholia as the issue is finally out.

Sparse is compact and in press (special issue)

2011-07-22T15:14:00.000-07:00

Szeged University Memorial plaque in honor of Haar and Riesz

All papers in press for the Special Issue of Signal Processing on "Multirate Filter Bank Structures and Multiscale Representations" (announced here at Nuit Blanche) are now available online and published in Volume 91, Issue 12, December 2011. 100 years after Alfred Haar seed, with the help of about 100 reviewers. While waiting for the paperback versions in the solid world, have a look at the following contributions in digital form, gathered on a dedicated page Signal Processing: Special issue on Advances in Multirate Filter Bank Structures and Multiscale Representations. They deal with 1-D signals to 2-D images, from image coding to compressive sensing, from fixed to adaptive representations, with a common bias toward sparsity. Forthcoming "call for papers" in 2011, related to sparsity, were gathered in a previous post: Sparse is abundant.

A century after the first outbreak of wavelets in Alfred Haar's thesis in 1909, filter banks and wavelet transforms lie at the heart of many digital signal processing and communication systems. During the last thirty years, they have been the focus of tremendous theoretical advances and practical applications in a growing digital world. They are for instance present, as local linear expansions, at the core of many existing or forthcoming audio, image or video compression algorithms.

Beyond standards, many exciting developments have emerged in filter banks and wavelets from the confrontation between scientists from different fields (including signal and image processing, computer science, harmonic analysis, approximation theory, statistics, bioengineering, physics,\ldots). At their confluence, multiscale representations of data, associated with their efficient processing in a multirate manner, have unveiled tools or refreshed methods impacting the whole data management process, from acquisition to interpretation, through communications, recovery and visualization. Multirate structures naturally shelter key concepts such as the duality between redundancy and sparsity, as well as means for extracting low dimensional structures from higher ones. In image processing in particular, various extensions of wavelets provide smart linear tools for building insightful geometrical representations of natural images.
The purpose of this special issue is to report on recent progresses performed, and emerging trends, in the domain of multirate filter banks and multiscale representations of signals and images. Topics addressed faithfully reflect the active research pertaining to this field, including sparse representations of (1-D) signals to (2-D) images, multiscale models and processing, shrinkage and denoising, compressive sensing, oversampled discrete frames, geometrical multiscale transforms, hybrid and adaptive representations and non-separable lifting for image compression.

Fast orthogonal sparse approximation algorithms over local dictionaries (DOI:10.1016/j.sigpro.2011.01.004)

Boris Mailhé and Rémi Gribonval and Pierre Vandergheynst and Frédéric Bimbot

Abstract:

In this work we present a new greedy algorithm for sparse approximation called LocOMP.
LocOMP is meant to be run on local dictionaries made of atoms with much shorter supports than the signal length.
This notably encompasses shift-invariant dictionaries and time-frequency dictionaries, be they monoscale or multiscale.
In this case, very fast implementations of Matching Pursuit are already available.
LocOMP is almost as fast as Matching Pursuit while approaching the signal almost as well as the much slower Orthogonal Matching Pursuit.

Keywords:

Sparse approximation; Greedy algorithms; Shift invariance; Orthogonal Matching Pursuit

Recursive Nearest Neighbor Search in a Sparse and Multiscale Domain for Comparing Audio Signals (DOI:10.1016/j.sigpro.2011.03.002)

Bob Sturm and Laurent Daudet

Abstract:

We investigate recursive nearest neighbor search in a sparse domain
at the scale of audio signals.
Essentially, to approximate the cosine distance between the signals
we make pairwise comparisons between
the elements of localized sparse models built from
large and redundant multiscale dictionaries of time-frequency atoms.
Theoretically, error bounds on these approximations provide
efficient means for quickly reducing the search space to
the nearest neighborhood of a given data;
but we demonstrate here that the tightest bound
involving a probabilistic assumption does not provide a practical approach
for comparing audio signals with respect to this distance measure.
Our experiments show, however, that regardless of these non-discriminative bounds,
we only need to make a few atom pair comparisons
to reveal, e.g., the position of origin of an excerpted signal,
or melodies with similar time-frequency structures.

Keywords:

Multiscale decomposition; Sparse approximation; Time—frequency dictionary; Audio similarity

Symmetric Tight Frame Wavelets With Dilation Factor M=4 (DOI:10.1016/j.sigpro.2011.05.005)

Farras Abdelnour

Abstract:

In this paper we discuss a new set of symmetric tight frame wavelets with the associated filterbank outputs downsampled by four at each stage. The frames consist of seven generators obtained from the lowpass filter using spectral factorization, with the lowpass filter obtained via Groebner basis method. The filters are simple to construct, and offer smooth scaling functions and wavelets. Additionally, the filterbanks presented in this paper have limited redundancy while maintaining the smoothness of underlying limit functions. The filters are linear phase (symmetric), FIR, and the resulting wavelets possess vanishing moments.

Keywords:

Wavelet transform; Frame; Symmetric filterbanks; Multiresolution analysis

Activelets: Wavelets for Sparse Representation of Hemodynamic Responses (DOI:10.1016/j.sigpro.2011.03.008)

Ildar Khalidov and Jalal Fadili and Francois Lazeyras and Dimitri Van De Ville and Michael Unser

Abstract:

We propose a new framework to extract the activity-related component in the BOLD functional Magnetic Resonance Imaging (fMRI) signal. As opposed to traditional fMRI signal analysis techniques, we do not impose any prior knowledge of the event timing. Instead, our basic assumption is that the activation pattern is a sequence of short and sparsely-distributed stimuli, as is the case in slow event-related fMRI.

We introduce new wavelet bases, termed ``activelets'', which sparsify the activity-related BOLD signal. These wavelets mimic the behavior of the differential operator underlying the hemodynamic system. To recover the sparse representation, we deploy a sparse-solution search algorithm.

The feasibility of the method is evaluated using both synthetic and experimental fMRI data. The importance of the activelet basis and the non-linear sparse recovery algorithm is demonstrated by comparison against classical B-spline wavelets and linear regularization, respectively.

Keywords:

BOLD fMRI; Hemodynamic response; Wavelet design; Sparsity; l1 minimization

Resonance-Based Signal Decomposition: A New Sparsity-Enabled Signal Analysis Method (DOI:10.1016/j.sigpro.2010.10.018)

Ivan Selesnick

Abstract:

Numerous signals arising from physiological and physical processes, in addition to being non-stationary, are moreover a mixture of sustained oscillations and non-oscillatory transients that are difficult to disentangle by linear methods. Examples of such signals include speech, biomedical, and geophysical signals. Therefore, this paper describes a new nonlinear signal analysis method based on signal resonance, rather than on frequency or scale, as provided by the Fourier and wavelet transforms. This method expresses a signal as the sum of a ‘high-resonance’ and a ‘low-resonance’ component—a high-resonance component being a signal consisting of multiple simultaneous sustained oscillations; a low-resonance component being a signal consisting of non-oscillatory transients of unspecified shape and duration. The resonance-based signal decomposition algorithm presented in this paper utilizes sparse signal representations, morphological component analysis, and constant-Q (wavelet) transforms with adjustable Q-factor.

Keywords:
Sparse signal representation; Constant-Q transform; Wavelet transform; Morphological component analysis

Multivariate empirical mode decomposition and application to multichannel filtering (DOI:10.1016/j.sigpro.2011.01.018)

Amar Kachenoura and Julien Fleureau and Laurent Albera and Jean-Claude Nunes and Lotfi Senhadji

Abstract:

Empirical Mode Decomposition (EMD) is an emerging topic in signal processing research, applied in various practical fields due in particular to its data-driven filter bank properties. In this paper, a novel EMD approach called X-EMD (eXtended-EMD) is proposed, which allows for a straightforward decomposition of mono- and multivariate signals without any change in the core of the algorithm. Qualitative results illustrate the good behavior of the proposed algorithm whatever the signal dimension is. Moreover, a comparative study of X-EMD with classical mono- and multivariate methods is presented and shows its competitiveness. Besides, we show that X-EMD extends the filter bank properties enjoyed by monovariate EMD to the case of multivariate EMD. Finally, a practical application on multi-channel sleep recording is presented.

Keywords:
Mono- and multivariate empirical mode decomposition; Filter bank structure; Electroencephalography data analysis

A Panorama on Multiscale Geometric Representations, Intertwining Spatial, Directional and Frequency Selectivity (DOI:10.1016/j.sigpro.2011.04.025)

Laurent Jacques and Laurent Duval and Caroline Chaux and Gabriel Peyré

Abstract:

The richness of natural images makes the quest for optimal representations in
image processing and computer vision challenging. The latter observation has
not prevented the design of image representations, which trade off between
efficiency and complexity, while achieving accurate rendering of smooth regions
as well as reproducing faithful contours and textures. The most recent ones,
proposed in the past decade, share an hybrid heritage highlighting the
multiscale and oriented nature of edges and patterns in images. This paper
presents a panorama of the aforementioned literature on decompositions in
multiscale, multi-orientation bases or dictionaries. They typically exhibit
redundancy to improve sparsity in the transformed domain and sometimes its
invariance with respect to simple geometric deformations (translation,
rotation). Oriented multiscale dictionaries extend traditional wavelet
processing and may offer rotation invariance. Highly redundant dictionaries
require specific algorithms to simplify the search for an efficient (sparse)
representation. We also discuss the extension of multiscale geometric
decompositions to non-Euclidean domains such as the sphere or arbitrary meshed
surfaces. The etymology of panorama suggests an overview, based on a choice of
partially overlapping "pictures". We hope that this paper will contribute to
the appreciation and apprehension of a stream of current research directions in
image understanding.

Keywords:
Review; Multiscale; Geometric representations; Oriented decompositions; Scale-space; Wavelets; Atoms; Sparsity; Redundancy; Bases; Frames; Edges; Textures; Image processing; Haar wavelet; Non-Euclidean wavelets

Bandlet Image Estimation with Model Selection (DOI:10.1016/j.sigpro.2011.01.013)

Charles Dossal and Stéphane Mallat and Erwan Le Pennec

Abstract:

To estimate geometrically regular images in the white noise model and
obtain an adaptive near asymptotic minimaxity result, we consider a model selection
based bandlet
estimator. This bandlet estimator combines the best basis selection
behaviour of the model selection and the
approximation properties of the bandlet dictionary.
We derive its near asymptotic minimaxity for geometrically regular images as an
example of model selection with general dictionary of orthogonal bases.
This paper is thus
also a self contained tutorial on model selection with orthogonal bases dictionary.

Keywords:
Model selection; White noise model; Image estimation; Geometrically regular functions; Bandlets

Augmented Lagrangian based Reconstruction of non-uniformly sub-Nyquist sampled MRI data (DOI:10.1016/j.sigpro.2011.04.033)

Jan Aelterman and Hiep Luong and Bart Goossens and Aleksandra Pizurica and Wilfried Philips

Abstract:

MRI has recently been identified as a promising application for compressed-sensing-like regularization because of its potential to speed up the acquisition while maintaining the image quality. Thereby non-uniform k-space trajectories, such as random or spiral trajectories, are becoming more and more important, because they are well suited to be used within the compressed-sensing (CS) acquisition framework. In this paper, we propose a new reconstruction technique for non-uniformly sub-Nyquist sampled k-space data. Several parts make up this technique, such as the non-uniform Fourier transform (NUFT), the discrete shearlet transform and a augmented Lagrangian based optimization algorithm. Because MRI images are real-valued, we introduce a new imaginary value suppressing prior, which attenuates imaginary components of MRI images during reconstruction, resulting in a better overall image quality. Further, a preconditioning based on the Voronoi cell size of each NUFT data point speeds up the conjugate gradient optimization used as part of the optimization algorithm. The resulting algorithm converges in a relatively small number of iterations and guarantees solutions that fully comply to the imposed constraints. The results show that the algorithm is applicable not only to sub-Nyquist sampled k-space reconstruction, but also to MR image fusion and/or resolution enhancement.

Keywords:
Augmented Lagrangian methods; MRI reconstruction; Non-uniform Fourier transform; Shearlet; Compressed sensing

Matching Pursuit Shrinkage in Hilbert Spaces (DOI:10.1016/j.sigpro.2011.04.010)

Tieyong Zeng and Francois Malgouyres

Abstract:

In this paper, we study a variant of the Matching Pursuit named Matching Pursuit Shrinkage. Similarly to the Matching Pursuit it seeks for an approximation of a datum living in a Hilbert space by a sparse linear expansion in a countable set of atoms. The difference with the usual Matching Pursuit is that, once an atom has been selected, we do not erase all the information along the direction of this atom. Doing so, we can evolve slowly along that direction. The goal is to attenuate the negative impact of bad atom selections.

We analyze the link between the shrinkage function used by the algorithm and the fact that the result belongs to $l^2$, $l^1$ and $l^0$ space. Experimental results are also reported to show the potential application of the proposed algorithm.

Keywords:
Dictionary; Matching pursuit; Shrinkage; Sparse representation

Non Separable Lifting Scheme with Adaptive Update Step for Still and Stereo Image Coding (DOI:10.1016/j.sigpro.2011.01.003)

Mounir Kaaniche and Amel Benazza-Benyahia and Béatrice Pesquet-Popescu and Jean-Christophe Pesquet

Abstract:

Many existing works related to lossy-to-lossless multiresolution image compression are based on the lifting concept. It is worth noting that a separable lifting scheme may not appear very efficient to cope with the 2D characteristics of edges which are neither horizontal nor vertical. In this paper, we propose to use 2D non-separable lifting schemes that still enable progressive reconstruction and exact decoding of images. Their relevant advantage is to yield a tractable optimization of all the involved decomposition operators. More precisely, we design the prediction operators by minimizing the variance of the detail coefficients. Concerning the update filters, we propose a new optimization criterion which aims at reducing the inherent aliasing artifacts. A theoretical analysis of the proposed method is conducted in terms of the adaptation criterion considered in the optimization of the update filter. Simulations carried out on still images and residual ones generated from stereo pairs show the benefits which can be drawn from the proposed optimization of the lifting operators.

Keywords:
Lossless compression; Progressive reconstruction; Lifting schemes; Separable transforms; Non-separable transforms; Adaptive transforms; Multiresolution analysis; Wavelets; Stereo coding

Sparse is abundant

2011-06-18T15:02:00.000-07:00

William of Ockham

[Updated 2011/06/19 for iTWIST 2012 workshop in Marseille, see at bottom]
[Updated 2011/07/02 for a call of paper to Journal of Applied Mathematics on "Preconditioning Techniques for Sparse Linear Systems"]

You still have one day (deadline: 2011/06/19) to submit a paper to ACM Multimedia SRED 2011 : First International Workshop on Sparse Representation for Event Detection in Multimedia, from 28. Nov. to 1 Dec. in Arizona, USA.

Should you need a little more time, an oxymoric abundance of calls for papers related to sparsity offers additional opportunities. Let's hope your submissions will spark interesting discussions on sparsity on Nuit Blanche. (BTW, thank you Igor for promoting a PhD thesis proposal related to sparsity and seismics, i'll try to make it more international soon).

Journal: EURASIP Journal on Advances in Signal Processing
Special issue: New Image and Video Representations Based on Sparsity
Editors : Fred Truchetet, Université de Bourgogne; Akram Aldroubi, Department of Mathematics, Vanderbilt University; Ivan W. Selesnick, Polytechnic Institute of New York University; Peter Schelkens, Vakgroep Elektronica en Informatieverwerking, Vrije Universiteit Brussel; Olivier Laligant, Université de Bourgogne, Dijon, Bourgogne, France

Submission deadline: apparently open until June 30 2011 [2011/06/30], see this page (CfP)

In recent years, new signal representations based on sparsity have drawn considerable attention. Natural images can be modeled by sparse models living in high-dimensional spaces. New efficient algorithms based on sparse representations have been recently proposed and successfully applied to many image and video processing problems.This special issue will focus on how sparsity has impacted image and video processing. It intends to be an international forum for researchers to summarize the most recent developments, trends, and new ideas in the field of sparse representations and their applications to image and video processing and hence highlight the advances in this field. The topics to be covered include, but are not limited to:

Sparse representations for image and video

Multiresolution approaches, Wavelet, and X-let analysis for image processing

Compressed sensing

Applications of sparsity to image denoising, compression, segmentation, restoration, recognition, inpainting, super resolution, and so forth

Journal: EURASIP Journal on Advances in Signal Processing
Special issue: Sparse Signal Processing
Editors: Farokh Marvasti, Advanced Communications Research Institute, Sharif University of Technology; Jonathon Chambers, Advanced Signal Processing Group, Department of Electronic and Electrical Engineering, Loughborough University; Mohammad Djafari, CNRS, Ecole supérieure d'éléctricité (Supélec)

Submission deadline: July 15, 2011 [2011/07/15] (CfP)

An emerging important area of signal processing is the case when the signal is sparse in any transform domain. Sparse signal processing reveals significant reduction in the sampling rate and processing manipulations. Efficient algorithms have been developed for sparse signals for various applications; the algorithms developed seem to be application specific. It is the aim of this special issue to compare so many algorithms for these applications. The goal is a unified view of sparse signal processing by bringing together various fields.The key applications of sparse signal processing are sampling, coding, spectral estimation, array processing, component analysis, and multipath channel estimation. In terms of reconstruction algorithms papers are solicited in, but are not limited to:

Random sampling

Compressed sensing

Rate of innovation

Real Galois field error correction codes

Spectral estimation

Multisource location

DOA estimation in array processing

Sparse array beamforming

Sparse sensor networks

Blind source separation in SCA

Multipath channel estimation

Journal: International Journal of Mathematics and Mathematical Sciences
Special issue: Sparse Sampling and Sparse Recovery and Its Applications to Inverse Problems
Editors: Gerd Teschke, Institute for Computational Mathematics in Science and Technology, Neubrandenburg University of Applied Sciences; Anders Hansen, Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge; Ronny Ramlau, Industrial Mathematics Institute, Johannes Kepler University

Submission deadline: September 1st, 2011 [2011/09/01] (CfP)

Many applications in science and engineering require the solution of an operator equation Kx = y. Often only noisy data are available, and if the problem is ill posed, regularization methods have to be applied for the stable approximation of a solution. Influenced by the huge impact of sparse signal representations and the practical feasibility of advanced sparse recovery algorithms, the combination of sparse signal recovery and inverse problems emerged in the last decade as a new growing area. Currently, there exist a great variety of sparse recovery algorithms for inverse problems. These algorithms are successful formany applications and have lead to breakthroughs in many fields (e.g., MRI, tomography). However, the feasibility is usually limited to problems for which the data are complete and where the problem is of moderate dimension. For really large-scale problems or problems with incomplete data, these algorithms are not well suited or fail completely. In the context of signal recovery, generalized sampling theories were developed to tackle the problem of data incompleteness. One outstanding approach is the theory of compressed sensing. A major breakthrough was achieved when it was proven that it is possible to reconstruct a signal from very few measurements. A crucial condition for compressed sensing is the so-called restricted isometry property. Nowadays, this strong requirement has been relaxed in several ways, but so far all formulations of compressed sensing are in finite dimensions. Quite recently, first attempts of infinite dimensional formulations emerged. In this special issue, our focus is on stable and numerically feasible recovery algorithms and–and this is one major question–whether these technologies generalize to the solution of operator equations/inverse problems. Hence we invite authors to submit original research papers and review articles that provide the state of the art in this field and extend the known theory and contribute therefore to answer these questions. We are interested in articles that explore aspects of generalized sparse sampling, sparse recovery, and inverse problems. Potential topics include, but are not limited to:

Generalized sampling principles and stable reconstruction

Compressed sampling strategies and the solution of operator equations

Compressive sampling principles and their extensions to infinite dimensions

Sparse recovery principles for inverse problems

Regularization theory for inverse problems with sparsity constraints

Algorithms and their numerical realization

Journal: Neurocomputing

Special issue: Distributed Machine Learning and Sparse Representation with Massive Data Sets

Editors: Oliver Obst CSIRO ICT Centre, Sydney, ; Tiberio Caetano NICTA, Canberra, ; Michael Mahoney Stanford University, Stanford

Submission deadline: September 16, 2011 [2011/09/16]

The exponentially increasing demand for computing power as well as physical and economic limitations has contributed to a proliferation of distributed and parallel computer architectures. To make better use of current and future high-performance computing, and to fully benefit from these massive amounts of data, we must discover, understand and exploit the available parallelism in machine learning. Simultaneously, we have to model data in an adequate manner while keeping the models as simple as possible, by making use of a sparse representation of the data or sparse modelling of the respective underlying problem.

This special issue follows the 2011 Symposium on "Distributed Machine Learning and Sparse Representation with Massive Data Sets" (DMMD 2011). We invite both new submissions as well as previously unpublished work that have been presented on DMMD 2011. Suggested topics for this special issue include:

Distributed, Multicore and Cluster based Learning Techniques

Machine Learning on Alternative Hardware (GPUs, Robots, Sensor Networks, Mobile Phones, Cell Processors ...)

Sparsity in Machine Learning and Statistics

Learning results and techniques on Massive Datasets

Dimensionality Reduction, Sparse Matrix, Large Scale Kernel Methods

Fast Online Algorithms for Large Scale Data

Parallel Computing Tools and Libraries

Journal: Journal of Visual Communication and Image Representation (JVCI)
Special issue: Sparse Representations for Image and Video Analysis
Editors: Jinhui Tang, Nanjing University of Science and Technology; Shuicheng Yan, National University of Singapore; John Wright, Microsoft Research Asia; Qi Tian, University of Texas at San Antonio; Yanwei Pang, Tianjin University; Edwige Pissaloux, Université Pierre et Marie Curie

Submission deadline: October 1, 2011 [2011/10/01] (CfP)

Sparse representation has gained popularity in the last few years as a technique to reconstruct a signal with few training examples. This reconstruction can be defined as adaptively finding a dictionary which best represents the signal on sample bases. Sparse representation establishes a more rigorous mathematical framework for studying high-dimensional data and ways to uncover the structures of the data, giving rise to a large repertoire of efficient algorithms. The sparse representation has just been applied to visual analysis for few years, while has shown its advantages in processing the visual information. Thus it will have a great potential in this field.
Sparse representation has wide applications in image/video processing, analysis, and understanding, such as denoising, deblurring, inpainting, compression, super-resolution, detection, classification, recognition, and retrieval. Many approaches based on sparse representation were proposed for these applications in the past years, and showed the promising results. This special issue aims to bring together the range of research efforts in sparse representation for image/video processing, analysis, and understanding. The goals of this special issue are threefold: (1) to introduce the advances of the theories on sparse representation; (2) to survey the progress of the applications of sparse representation in visual analysis; and (3) to discuss new sparse representation based technologies that will be potentially impactful in the image/video applications (primary results are needed).

The scope of this special issue is to cover all aspects that relate to sparse representation for visual analysis. Topics of interest include, but are not limited to the following:

The fundamental theories on sparse representation

Dictionary learning for sparse representation and modeling

The novel learning methods based on sparse representation

The applications of sparse representation in image/video denoising, impainting, debluerring, compression, and super-resolution

Sparse representation for pattern recognition and classification

Sparse representation for image/video retrieval

Sparse reconstruction for medical imaging and radar imaging

Sparse component analysis and its application to blind source separation

Journal: IEEE Journal of Selected topics in Signal Processing
Special issue: Robust Measures and Tests Using Sparse Data for Detection and Estimation
Editors: Hsiao-Chun Wu, Louisiana State University; Philippe Ciblat, ENST; Octavia A. Dobre, Memorial University of Newfoundland; Jitendra K. Tugnait, Auburn University
Submission deadline: March 28, 2011 (apparently past, still on the "Open Special Issues" page, yet on the upcoming publications, due February 2012) (CfP)

The sparse (undersampled) data constraint in the statistical signal processing is quite common for efficient computation and system time-invariance validity. Hence, the research about how to build reliable statistical measures and statistical tests using sparse data for different signal processing applications is still quite challenging nowadays. When the real-time efficiency or the unnoticeable processing delay is required with the help of the state-of-the-art microprocessors or DSP platforms, researchers are still making continual efforts to develop new robust statistical methodologies. Two crucial indicators, “number-of-samples to number-ofparameters- to-be-estimated ratio” (referred to as SPR) and “system performance versus signal-to-interferenceplus- noise ratio”(referred to as SPSINR), can reflect both sparse data constraint and robustness. The objective is to seek new ideas and techniques to surmount the existing signal processing methods in terms of low SPR and superior SPSINR but still achieve good computational efficiency. In the signal processing research, reliable statistical measures such as statistical moments/cumulants, Lp-norms, mean-square-errors (MSE), Cramer-Rao bounds (CRB), signal-to-noise ratio (SNR), signal-to-interference ratio (SIR), mutual information/entropy, divergence, etc. are always in pursuit, especially subject to the restriction on the limited data and/or the time variance of the underlying systems instead of the classical asymptotical analysis based on the infinite data set. This special issue will focus on all aspects of design, development, implementation, operation, and applications of robust measures and tests using sparse data for detection and estimation.

We invite original and unpublished research contributions in all areas relevant to signal processing in cooperative cognitive radio systems. The topics of interest include, but are not limited to:

New robust measures or objective functions for detection and estimation using sparse data

New robust statistical tests for detection and estimation using sparse data

New theoretical and empirical analyses for detection and estimation using sparse data

New results for explicit expressions of CRB or variance for detection and estimation using sparse data

Reliable signal quality measures using sparse data

General frameworks for evaluating various statistical measures/tests using sparse data

Journal: Journal of Applied Mathematics
Special issue: Special Issue on Preconditioning Techniques for Sparse Linear Systems
Editors: Massimiliano Ferronato, Department of Mathematical Methods and Models for Scientific Applications, University of Padova, Padova, Italy; Edmond Chow, School of Computational Science and
Engineering, College of Computing, Georgia Institute of Technology, Atlanta; Kok Kwang Phoon, Department of Civil Engineering, National University of Singapore

Submission deadline: November 1, 2011 [2011/11/01] (CfP Special Issue on Preconditioning Techniques for Sparse Linear Systems)

The accurate and efficient solution to sparse linear systems of equations, arising from the discretization of PDEs, often represents the main memory- and time-consuming tasks in a computer simulation. Direct methods are still widely used on the basis of their robustness and reliability. However, they generally scale poorly with the matrix size, especially on 3D problems. For large sparse systems, iterative methods based on Krylov subspaces are a most attractive option. Several Krylov subspace solvers have been developed during the 1970s through the 1990s, and they are generating a growing interest in many areas of engineering and scientific computing. Nonetheless, to become really competitive with direct solvers they need an appropriate preconditioning to achieve convergence in a reasonable number of iterations.

It is widely recognized that preconditioning is the key factor to increase the robustness and the computational efficiency of iterative methods. Unfortunately, theoretical results are few, and it is not rare that “empirical” algorithms work surprisingly well despite the lack of a rigorous foundation. The research on preconditioning has significantly grown over the last two decades and currently appears to be a much more active area than either direct or iterative solution methods. On one hand, this is due to the understanding that there are virtually no limits to the available options for obtaining a good preconditioner. On the other hand, it is also generally recognized that an optimal general-purpose preconditioner is unlikely to exist, so new research fields can be opened for improving the computational efficiency in the solution of any specific problem at hand on any specific computing environment.

We invite investigators to contribute original research articles as well as review articles on the development and the application of preconditioning techniques for the solution to sparse linear systems. Potential topics include, but are not limited to:

Development and numerical testing of novel preconditioners

Development and numerical testing of preconditioners for specific applications

Improvement of existing general-purpose algebraic preconditioners

Theoretical advances on the properties of existing general-purpose algebraic preconditioners

Application of existing techniques to novel fields

Additional conference events are found at the Compressive sensing meetings page or SIVA Conferences (not updated often enough these times). Let us mention:

The first international Travelling Workshop of Interaction between Sparse models and Technologies (iTWIST 2012), May 9-11, 2012, at CIRM, in Marseilles, France, on "Generalized sparsity in high-dimensional geometries". The range of topics will include (but may not be limited to) :

Graph theory and applications

Dictionary learning

Sparse models in machine learning

Compressed sensing

Emerging and innovative acquisition technologies such as:
* compressive imagers
* hyperspectral imaging
* analog to information converter
* coded aperture system
* computational photography

Applications to real-life problems (astronomy, biomedical, industry, multimedia and any other field ... )

Organisers: Dr. Sandrine Anthoine, Prof. Yannick Boursier, Prof. Pascal Frossard, Dr. Laurent Jacques, Prof. Pierre Vandergheynst, Prof. Christophe De Vleeschouwer
Probably more information soon at: http://marwww.in2p3.fr/~boursier/

For the near present, we are awaiting the upcoming (September 2011) Adaptive Sparse Representation of Data and Applications in Signal and Image Processing (IEEE Journal of Selected topics in Signal Processing) and the "very very sparse" special issue "Sparse Representation of Data and Images" in Advances in Adaptive Data Analysis. Theory and Applications, which appears only on a few places (Improved analysis of the subsampled randomized Hadamard transform, cited by A Note on Low-rank Matrix Decompositions via the Subsampled Randomized Hadamard Transform).

Finally, the special issue of Signal Processing on Advances in Multirate Filter Bank Structures and Multiscale Representations is complete; 4 out of 11 papers refer to sparsity in their title, all of them in their text. Sparsity is no self-referential concept these days.

Decimate Brands of Banded matrices

2011-03-19T15:46:00.000-07:00

About one year ago Gilbert Strang published a first paper Fast transforms: Banded matrices with banded inverses at Proceedings of the National Academy of Science (PNAS), with the following abstract:

It is unusual for both $A$ and $A^{-1}$ to be banded — but this can be a valuable property in applications. Block-diagonal matrices $F$ are the simplest examples; wavelet transforms are more subtle. We show that every example can be factored into $A = F_1 \dots F_N$ where $N$ is controlled by the bandwidths of $A$ and $A^{-1}$ (but not by their size, so this extends to infinite matrices and leads to new matrix groups).

Banded matrices (or band matrices) are somewhat related to implementations of discrete wavelet transforms (see for instance Short Wavelets and Matrix Dilation Equations, 1995 by G. Strang and V. Strela). The 2010 PNAS sparked some interest as a means to implement fast local linear filters in both the forward and inverse transforms (an ascribed tandem, first anagram to banded matrices), by splitting matrices into ones faster to compute. In Unraveling the Matrix (A new way of analyzing grids of numbers known as matrices could improve signal-processing applications and data-compression schemes) at MIT News, Larry Hardesty states that:

In a paper published in the July 13 issue of Proceedings of the National Academy of Science, MIT math professor Gilbert Strang describes a new way to split certain types of matrices into simpler matrices. The result could have implications for software that processes video or audio data, for compression software that squeezes down digital files so that they take up less space, or even for systems that control mechanical devices.
[...]
Richard Brualdi, the emeritus UWF Beckwith Bascom Professor of Mathematics at the University of Wisconsin-Madison, points out that a mathematical conjecture that Strang presents in the paper has already been proven by three other groups of researchers. “It’s a very interesting theorem,” says Brualdi. “It’s already generated a couple of papers, and it’ll probably generate some more.” Brualdi points out that large data sets, such as those generated by gene sequencing, medical imaging, or weather monitoring, often yield matrices with regular structures. Bandedness is one type of structure, but there are others, and Brualdi expects other mathematicians to apply techniques like Strang’s to other types of structured matrices. “Whether or not those things will work, I really don’t know,” Brualdi says. “But Gil’s already said that he’s going to look at a different structure in a future paper.”

The chronicle can been read at Dr. Dobbs and here in pdf as well. And News I care mentioned it briefly in Fast signal transform with Banded matrix method.

The blog of a mandated scribe (on mixed banded matrices) can be used as a note to self. I completely forgot to read that paper, which was openly available at the time. Thanks to an update at Gilbert Strang's pdf paper repository, a few related others are now shared in pdf:

Fast transforms: Banded matrices with banded inverses, Proc. National Academy of Sciences 107 (#28) (2010) 12413-12416.

Abstract above

Banded Matrices with Banded Inverses and A = LPU, Proceedings Intl. Congress of Chinese Mathematicians: ICCM2010, to appear.

If $A$ is a banded matrix with a banded inverse, then $A = BC = F_1 \dots F_N$ is a product of block-diagonal matrices. We review this factorization, in which the $F_i$ are tridiagonal and $N$ is independent of the matrix size. For a permutation with bandwidth $w$, each $F_i$ exchanges disjoint pairs of neighbors and $N < 2w$. This paper begins the extension to infinite matrices. For doubly infinite permutations, the factors $F$ now include the left and right shift. For banded infinite matrices, we discuss the triangular factorization $A = LPU$ (completed in a later paper on The Algebra of Elimination). Four directions for elimination give four factorizations $LPU$ and $UPL$ and $U_1 \pi U_2$ (Bruhat) and $L_1 \pi L_2$ with different $L$, $U$, $P$ and $\pi$.

Groups of banded matrices with banded inverses, Proc. AMS, to appear (2011)

A product $A = F_1 \dots F_N$ of invertible block-diagonalmatrices will be bandedwith a banded inverse. We establish this factorization with the number $N$ controlled by the bandwidths w and not by the matrix size n: When A is an orthogonal matrix, or a permutation, or banded plus finite rank, the factors $F_i$ have $w = 1$ and generate that corresponding group. In the case of infinite matrices, conjectures remain open.

Triangular factorizations: The algebra of elimination, submitted to SIAM Review (2011)

Elimination with only the necessary row exchanges will produce the triangular factorization $A = LPU$, with the (unique) permutation $P$ in the middle. The entries in $L$ are reordered in comparison with the more familiar $A = PLU$ (where $P$ is not unique). Elimination with three other starting points 1, $n$ and $n$, $n$ and $n$, 1 produces three more factorizations of $A$, including the Wiener-Hopf form $UPL$ and Bruhat’s $U_1 \pi U_2$ with two upper triangular factors.
All these starting points are useless for doubly infinite matrices. The matrix has no first or last entry. When A is banded and invertible, we look for a new way to establish $A = LPU$. First we locate the pivot rows (and the main diagonal of $A$). $LPU$ connects to the classical factorization of matrix polynomials developed for the periodic (block Toeplitz) case when $A(i,j) = A(i+b;j+b)$.

Only for anagram sake, these approaches may reanimate BDDCs (balancing domain decomposition by constraints), which may sound a macabre distend to acerbated minds walking on candidate berms.

Additional papers:
Factoring Permutation Matrices Into a Product of Tridiagonal Matrices (pdf) Michael Daniel Samson, Martianus Frederic Ezerman (July 2010)

Gilbert Strang posited that a permutation matrix of bandwidth $w$ can be written as a product of $N < 2w$ permutation matrices of bandwidth 1. A proof employing a greedy ``parallel bubblesort'' algorithm on the rows of the permutation matrix is detailed and further points of interest are elaborated.

Factorization Of Banded Permutations (pdf), Greta Panova (July 2010)

We prove a conjecture of Gilbert Strang stating that a banded permutation of bandwidth $w$ can be represented as a product of at most $2w-1$ permutations of bandwidth 1.

Approximating the inverse of banded matrices by banded matrices with applications to probability and statistics (pdf), Peter J. Bickel, Marko Lindner (February 2010)

In the first part of this paper we give an elementary proof of the fact that if an infinite matrix $A$, which is invertible as a bounded operator on $\ell^2$, can be uniformly approximated by banded matrices then so can the inverse of $A$. We give explicit formulas for the banded approximations of $A^{-1}$ as well as bounds on their accuracy and speed of convergence in terms of their band-width. In the second part we apply these results to covariance matrices $\Sigma$ of Gaussian processes and study mixing and beta mixing of processes in terms of properties of $\Sigma$. Finally, we note some applications of our results to statistics.

New words learned by myself today:
acerbated: embittered, resentful
berm: (1) a narrow shelf, path, or ledge typically at the top or bottom of a slope; also : a mound or wall of earth or sand (2) the shoulder of a road
distend: become wider, cause to expand as it by internal pressure, swell from or as if from internal pressure

Cucu fraternel - are there such things as french maths?

2010-10-01T13:57:00.000-07:00

For french listening folks only: "Mathématiques : quelle pérennité pour le prestige français ?" on France Culture today. Following the recent Fields medals, the discussion goes along the following tracks:

How long does it take to become a mathematician?
Has a 3-year long project some sense in mathematics?
Why is a paper outdated after 3 years in biology, while only after 30 years in maths?
Why a Minister of Higher Education and Research is so booked (s)he cannot attend such a debate?

Panel: Michel Broué, mathématicien, professeur à l’université Paris Diderot, Pierre Cartier, mathématicien, CNRS/IHES, Dominique Leglu, directrice de la rédaction de la revue Sciences et Avenir, Bertrand Monthubert, mathématicien, Institut de mathématiques de Toulouse, with interviews of Cédric Villani, mathématicien, professeur à l’Institut Camille Jordan, directeur de l’Institut Henri Poincaré et médaille Fields 2010 and Wendelin Werner, professeur de mathématiques, université Paris-Sud et Ecole normale supérieure Médaille Fields 2006 et membre de l’Académie des sciences.

Musical intermede: Gov't mule, Thorazine shuffle

Upcoming conferences (concern Fees) - The latent ones

2010-09-30T14:46:00.000-07:00

Saint-Malo Intra-Muros.

I went like an "animal sot" to Saint-Malo (Brittany) and returned enchanted by the 2010 edition of the Latent Variable Analysis and Independant Component Analysis (LVA-ICA 2010). The four excellent keynote/plenary speeches:

When tensor decomposition meets compressed sensing, by Pierre Comon (University of Nice, France), admittedly with an ad-like title, more akin to coherence than CS;
Discrimination with deformation for classification, by Stéphane Mallat (Ecole Polytechnique, France), when mapping complex wavelet coefficients to the lower frequencies yields a scattering metric;
Bayesian non-negative matrix factorisation methods to detect dye labelled DNA oligonucleotides in multiplexed Raman spectra, by Mark Girolami (University of Glasgow, UK);
2nd order statistics + A 3rd data dimension = Just weight and see!, by Arie Yeredor (Tel-Aviv University, Israel);

should be webcasted soon (stay tuned, i got audio bootlegs for personal use). Meanwhile, the next LVA/ICA 2012 will be held in Spring 2012 in Tel Aviv, Israel (see SIVA conferences). An internship is proposed in 2011 at IFP Energies nouvelles on that peculiar domain.

Among other latent events recently announced:
SPARS 2011 (Workshop: Signal Processing with Adaptive Sparse Structured Representations) in Edinburgh, Scotland (DL: 27/06/2011) from 30/06/2011 to 30/08/2010;
SSP 2011 (IEEE Workshop on Statistical Signal Processing) in Nice, France (DL: 15/01/2011) for 28/06/2011 to 30/06/2011;
ICCV 2013 (International Conference on Computer Vision) is announced in Barcelona, Spain;
GenSIPS 2010 (IEEE International Workshop on Genomic Signal Processing and Statistics) at Cold Spring Harbor USA-NY from 10/11/2010 to 12/11/2010;
DSP 2011 (International Conference on Digital Signal Processing) in Corfu, Greece (DL: 14/01/2011) from 06/07/2011 to 08/07/201;

See my very appreciation to Yves Meyer's price

2010-08-19T14:17:00.000-07:00

Emys turtle from http://en.wikipedia.org/wiki/Emys

While a decent anagram with two "y" and four "e" still hides under the carpet (much better ones related to Alain Connes, Fields medalist), see my very appreciation to Yves Meyer's Carl Friedrich Gauss price (here in French), four years after Kiyoshi Itō. At ICM 2010, it is said that, along with his work on wavelets ("wavelet theory has become the new name for Fourier analysis", gosh!),

[...] he has found a surprising connection between his early work on the model sets used to construct quasicrystals — the ‘Meyer Sets’ — and ‘compressed sensing’, a technique used for acquiring and reconstructing a signal utilizing the prior knowledge that it is sparse or compressible.

Which should please Igor Carron, of course. Every emys knows that every four years, Fields medals are attributed to talented mathematicians. The country of course honors Ngô Bao Châu (fundamental Lemma in the theory of automorphic forms through the introduction of new algebro-geometric methods) and Cédric Villani (proofs of nonlinear Landau damping and convergence to equilibrium for the Boltzmann equation, yet being director of IHP), along with Elon Lindenstrauss (results on measure rigidity in ergodic theory, and their applications to number theory) and Stanislas Smirnov (proof of conformal invariance of percolation and the planar Ising model in statistical physics). The Nevanlinna Prize and the Chern Prize go to Daniel Spielman and Louis Nirenberg respectively.

Let us end this with a typical mathanagram:

What’s an anagram of Banach-Tarski?
Banach-Tarski Banach-Tarski.

The turn of a friendly card - Train numbering trick

2010-07-23T14:53:00.000-07:00

Coming back from Orléans (France) on March 2010 for the Second conference "Mathematics and Image processing" (Deuxième colloque "Méthodes mathématiques pour l’image") organized at MAPMO. Having presented stuff on Statistical estimators based on Stein's principle for M-band wavelets and filter banks (abstract, slides, codes). Waiting in a train, staring again (and pixing) at the eight-seat compartment numbering once discussed here.

Since Igor Carron posted this Magic trick for summer vacations on Nuit Blanche (constest won by Laurent Jacques), I propose the following one again. Pictures attest the realness of the data, in contrast to Igor thought experiment (vicious tackle). Seat numbering is split in odd and even (unlike in six-seat cars), face-to-face, as:

.1 .3 .7 .5

.2 .8 .4 .6

The 3 (mod 8) sum is obvious. Easy enough for front-to-front booking by ancient computers. So why not the simple child Gauss-like arrangement?

.1 .3 .5 .7

.8 .6 .4 .2

Suspect some kind of compressive coding of seat booking? Contributions welcome.

One good reason to listen on Nits again - The train. TGIF; my train of thoughts is leaving (le train de mes pensées s'égare).

Or Alan Parson's project - Turn of the friendly card:

Leurrer ? Détrompez-vous ! - Dompterez-vous l'erreur ?

2010-07-21T14:18:00.000-07:00

Source : http://cereales.lapin.org/ (705)

On doit à René Thom (médaille Fields 1958) : "ce qui limite le vrai n’est pas le faux, mais l’insignifiant" [Paraboles et Catastrophes, Champs Flammarion, p. 127] (citation déjà évoquée à propos de l'antienne sur l'infobésité, ou la surabondance d'information de notre monde). On attribue à Wolfgang Pauli, pestant contre un article de physique sans intérêt, "ce n’est pas juste et, pire, ce n’est même pas faux !" (cf. WikiQuote on Pauli).

Cette idée n'est pas toujours évidente (voire contre intuitive) pour les élèves, étudiants, le grand public et - voire - pour une partie des contributeurs à la recherche scientifique.

Le festival "Science jeune public" (et peut-êre même les moins jeunes) oeuvre cette année dans le sens de cet éclaircissement sous le titre : Détrompez-vous (du 21 au 24 juillet 2010 à l'Ecole normale supérieure)

La Journée Grand Public qui aura lieu le samedi 24 juillet est ouverte à tous, sans réservation préalable. Extrait :

Les intervenants du festival vont s’efforcer cette année de faire tomber une idée reçue : l’erreur serait négative ! Dans tout processus d’apprentissage, comme dans la recherche, c’est en remettant en question des conceptions fausses que l’on progresse : il y a des erreurs nécessaires. Sur ce thème, qui vise à inciter chacun à oser entreprendre, de nombreux chercheurs, artistes, médiateurs, passionnés de sciences feront de ce festival un moment d’échanges intenses.

Alors, négative, l'erreur ? Résolument pas ! L'erreur a pour racine latine l'errance... Et s'égarer, sortir des sentiers battus : n'est-ce pas la voie de la créativité ? Osons donc explorer les chemins broussailleux où mènent les errances... Pour mieux rebondir, prenons le risque de nous tromper !

A diffuser aux ames curieuses : ateliers, animations, spectacles... On se quitte pour ce soir sur Jorge Ben : Errare humanum est ["A Tábua de esmeralda", 1972].

Upcoming SIVA signal and image conferences - Concern fees

2010-07-19T13:44:00.000-07:00

Today we update on the SIVA: Signal, Image, Video and Applications conferences page.

Long time ahead is ICASSP 2014 website running. Not much information yet, execpt in this information pdf file, like a call to image processing tools like inpainting. ICIP 2013 (Melbourne, Australia), ICASSP 2013 (Vancouver, Canada) are open but scarse as well.

Closer from us, SAMPTA 2011 held in Singapore (deadline on 01/10/2010), ISCAS 2011 in Rio de Janeiro, Brazil (deadline on 29/09/2011, sooner for Special sessions), ICASSP 2011 in Prague, Czech Rebublic (deadline on 20/10/2010), ICCV 2011 in Barcelona, Spain (deadline on 01/03/2011). ICIP 2011 in Brussels, Belgium, has no deadline for now. MWSCAS 2011, once believed in Brazil, will be in fabulous Seoul, South Korea (deadline 04/03/2010). SIVA would not be complete without the annual Conference on Digital Image Content Knowledge, held in Chicago, Illinois, USA. For myself, i will try to enjoy the shores of Saint-Malo at LVA/ICA 2010, the ninth conference on latent variable analysis and signal separation.

All this comes with a nomade gift: Skype version 5.0 for a portable use on a usb key.For people who like to do it themselves, look here.

Time is the simplest (non-commutative) thing

2010-07-10T05:40:00.000-07:00

One of the most elegant theorems of all times is 4-word: every finite field commutes (Wedderburn's little theorem). While having life-long interests in anagrams and questions about time, i never thought they were related. They are. Thanks to the conference: Un espace non-commutatif engendre son propre temps, by Alain Connes on 06 November 2007 in Metz, France (downloadable video, 220 Mb, flv format, since i failed in embedding it into the blog).

Alain Connes is both a tremendous mathematician and wonderful, passionate story-teller. A cryptic message by a friend's child:

Je suis Alençonnais, et non alsacien, si tu veux un conseil nana, rendez-vous au coin annales

and a story about book reading by japanese mathematician Minoru Tomita (and related results) lead us to a lesson on associativity and commutativity rules. Anagrams are possible only because written language is associative and non-commutative (no alternative!). Meaningful anagrams (such as seen in Remaniement) are seen as a commutative breach. What is important, says Alain Connes, is poetic spirit (not foreign to mathematics) and a clue on where you are heading (if you do not change direction, see Lao Tzu). Without too much mathematics, Connes conveys those insights (with Carlo Rovelli) that the sense of duration may well arises from the statistical state of a system, quite like temperature. A relic of the antic 3 K radiation of the Universe. Funny enough, both French and Italian languages have very close words for time (temps/tempo) and temperature (température/temperatura). Could they be physically closely related, as real and imaginery parts of a complex number? Do algebra have periods? Look at the audience questions at the end of the talk. See also: Alain Connes : une autre vision de l’espace.

Arte also proposes a series of questions to Carlo Rovelli, interestingly pertaining to the life of a physicist. Alain Connes book on Noncommutative Geometry is freely available in pdf. Clifford D. Simak (not the - associative - algebra) wrote one of the most poetic sci-fi book on time travel, Time is the simplest thing (Le pêcheur en langue française). M. Dhenin shares a series of radio broadcast in a Mindmap for time (in French).

Dimension-reduction, High-dimensional problems and solutions, Workshop, June 2010

2010-07-03T03:07:00.000-07:00

In epochs of information overload (or overlook), salvation comes from conferences like the HDPS 2010 workshop organized on 21 and 22 of June 2010 on High Dimensional Problems and Solutions, with Ron DeVore (Dep. of Mathematics,Texas A&M University, USA, recipient of the Foundation's Research Chaire of Excellence 2009) and Albert Cohen (UPMC, LJLL). Indeed:

Several important areas of science are confronted with the having to recover a functions of many variables either from large data sets or from complex mathematical models. Such recovery is inhibited by what is commonly called the 'curse of dimensionality' which says the numerical approximation of such a function will require inordinately more computation as the number of active variables increases. This workshop bring together the world's leading experts on high dimensional problems to discuss their recent research in areas such as manifold learning, stochastic and parametric PDEs, and optimal recovery.

The program was terrific:

Steve Smale (City University of Hong Kong) "Hodge Theory"
Mauro Maggioni (Duke) "Multiscale geometric methods for the analysis of points clouds"
Gilad Lerman (Univ. of Minnesota) "Multi-Manifold Data Modeling: Foundations and Applications"
Christoph Schwab (ETH Zurich) "Sparse Tensor Approximations of PDEs on high-dimensional parameter spaces"
Yvon Maday (Paris VI) "Reduced basis and magic point for high dimensional approximation problems"
Wolfgang Dahmen (RWTH Aachen) "A greedy approach for the reduced basis method - Convergence rates"
Emmanuel Vasquez (Supelec) "Gaussian processes, RKHS and their applications to computer experiments"
Przemek Wojtaszczyk (Univ. Warsaw) "Approximation of functions of few variables in high dimension "
Dominique Picard (Paris VII) "LOL: thresholdings and high dimensions"
Rob Nowak (Univ. of Wisconsin) "Adaptive and Nonlinear Designs for Large-Scale Multiple Hypothesis Testing"
Martin Wainwright (Berkeley) "Recovery problems in high dimensions: A unified analysis of estimators with decomposable regularizers"
Stephane Mallat (Polytechnique) "High dimensional classification by recursive interferometry"

As i could not attend, i am glad that most of it is now available as webcasts (gather at Foundation Sciences Mathématiques de Paris), as potential take-aways for summer holidays:

Mauro Maggioni (Duke): "Multiscale geometric methods for the analysis of points clouds",

http://www.dailymotion.com/video/xdrl5y_multiscale-geomet-methods-for-the-a_tech

Steve Smale (City University of Hong Kong): "Hodge Theory",

http://www.dailymotion.com/video/xdrlkg_hodge-theory-steve-smale_tech

Stephane Mallat (Polytechnique): "High dimensional classification by recursive interferometry",

http://www.dailymotion.com/video/xdshyp_high-dimensional-classification-by_tech

Martin Wainwright (Berkeley): "Recovery problems in high dimensions: A unified analysis of estimators with decomposable regularizers",

http://www.dailymotion.com/video/xdsfht_recovery-problems-in-high-dimension_tech

Rob Nowak (Univ. du Wisconsin): "Adaptive and Nonlinear Designs for Large-Scale Multiple Hypothesis Testing",

http://www.dailymotion.com/video/xdsf8b_adapt-nonlin-designs-for-large-scal_tech

Wolfgang Dahmen (RWTH Aachen, joint work with Peter Binev, Albert Cohen, Ronald DeVore, Guergana Petrova, and Przemyslaw Wojtaszczyk): Convergence Rates for Greedy Algorithms in Reduced Basis Methods,

http://www.dailymotion.com/video/xdrzb2_approach-for-the-reduced-basis-meth_tech

Peter Binev (Univ. Caroline du Sud): "Sparse Occupancy Trees",

http://www.dailymotion.com/video/xdsdcd_sparse-occupancy-trees-peter-binev_tech

Gilad Lerman (Univ. of Minnesota): "Multi-Manifold Data Modeling: Foundations and Applications",

http://www.dailymotion.com/video/xdrnb9_multi-manifold-data-model-gilad-ler_tech

Emmanuel Vazquez (Supelec): "Gaussian processes, RKHS and their applications to computer experiments",

http://www.dailymotion.com/video/xdrz78_gaussian-processes-rkhs-appli-to-co_tech

Yvon Maday (UPMC): "Reduced basis and magic point for high dimensional approximation problems",

http://www.dailymotion.com/video/xds0xd_reduced-basis-and-magic-point-for-h_tech

Przemek Wojtaszczyk (Univ. de Varsovie): "Approximation of functions of few variables in high dimension",

http://www.dailymotion.com/video/xds3j0_approximation-of-functions-of-few-v_tech

Dominique Picard (Université Paris-Diderot Paris-7): "LOL: thresholdings and high dimensions", http://www.dailymotion.com/video/xds3nm_lol-thresholdings-and-high-dimensio_tech

For dessert, a smoother video on "are soap bubbles all round?"

Thank you Igor for referencing.

Minotaure, tu dois finir ta thèse (again)

2010-06-25T22:47:00.000-07:00

Simon Berjeaut (espace MySpace) est l'auteur du Minotaure, ou "Tu dois finir ta thèse", un message d'espoir pour les doctorants et doctorantes en mal de manuscrit, dont je vous avais parlé il y a deux mois, et qu'Igor Carron avait proposé de rendre viral sur YouTube.

C'était à l'époque cendreuse de Eyjafjallajökull, et cette chanson évoque le piton de la Fournaise. Pourquoi le Minotaure ? Pour Thésée, l'homme perdu dans le labyrinthe que seul un fil ténu rappelle vers l'issue, une métaphore taurine illustrative du parcours du rédigeant de chaque doctorant. Thêseús comme Odysseus tant la parcours semble voyage sans fin. Mais aussi l'évocation de cette période surréaliste, par Minotaure, revue d'avant-guerre (la seconde) qui a fait diffuser des Roberto Matta, Alberto Giacometti, Hans Bellmer, Victor Brauner ou Tristan Tzara. Les deux derniers me rappelant un voyage en Roumanie. Roumanie + T = Minotaure (anagramme faible).

Les paroles ? Les paroles !

Où est ton regard de braise
Et tes airs conquérants
Tes épaules en trapèze
Et ta belle énergie
Tu as le regard qui biaise
De tous les doctorants
Et tu deviens obèse
Pris dans ta léthargie

Tu dois finir ta thèse
Tu dois finir ta thèse

Ton esprit de synthèse
Ta volonté de fer
Et ton désir d'acèse
Se sont-ils envolés ?
Au pied de la falaise
Tu ne sais plus comment faire
Ta volonté de glaise
Il faut la remodeler

Tu dois finir ta thèse
Tu dois finir ta thèse

Ce soir c'est repartit
Tu t'enfermes chez toi
Tu vas finir ta thèse
Ta décision est ferme
Ou au moins une partie
Ou bien le petit trois
Ou bien la parenthèse
Qu'il faut que je referme

Tu dois finir ta thèse

Tu vas finir demain
Tu dois finir le seize
Tu vas finir en juin
Bon, tu reprends une 16
Tu fumes un dernier joint
Et soudain tu t'apaises
Et doucement tu rejoins
Le mouvement des sans-thèse (x3)

Comme le dit Marie-Thérèse
Ta voisine martiniquaise
C'est comme le piton de la fournaise
Ça prendra comme une mayonnaise
C'est des foutaises
Tu vas finir ta thèse

Comme le dit Madame Hernandez
Dans sa sagesse toute portuguaise
Si aujourd'hui "nada c'est finich
ba ficar para la otra vezes"

C'est des fadaises
Tu vas finir ta thèse

Tu aimerais trouver un max de pèze
Caché dans une attaché-case
Tu partirais à Saint-Tropez
Tu irais faire du steeple-chase

Tu ferais pas ta thèse
Tu ferais plus du tout ta thèse

Même si la vie te pèse
Écarte l'hypothèse
De finir ta thèse
Au père Lachaise
Enfile tes charentaises
Rassied-toi sur ta chaise
Pas besoin de chanter la Marseillaise
Mais toi à l'aise
Tu vas finir ta thèse

Et ne vous en déplaise
Et tant pis si j'ai tord
Mais il me semble plus aisé
De poursuivre une thèse
Plutôt qu'un Minotaure
Tout le monde peut pas être Thésée
Tout le monde peut pas être Thésée
Thésée, Thésée

Mais taisez-vous
Punaise
[Quelle prise de thèse ?]

Tu vas finir ta thèse
Tu vas finir ta thèse

C'est infinisable
... Mais tu vas la finir
C'est insoutenable
... Mais tu vas la soutenir

Tu vas la finir
Tu vas la soutenir
Tu vas la publier, qui sait ?

Tu vas finir ta thèse
Tu vas finir ta thèse

La vertu d'un LA The virtue of an A - A fortunate hive

Ternary/trinary logic: bricks and trytes

Plagiarism: everything but the title

Conference: Fixing mathematical education

Hyperbolets (on WITS: Where is the Starlet)

Hyperbolets

Dry signal processing

WITS: Shearlets from MIA 2012

De la donnée à l'information : chimie et procédés

Call for papers: Advances in signal and image processing for physico-chemical analysis

(CfP: Deadline extension) Looking for new frontiers in signal and image processing applications in physico-chemical analysis? Have compressive sensing results for mass spectrometry? Got improvements on the Savitsky-Golay filter? Consider the following call for contributions.

Call for papers: Dossier, Special issue on Advances in signal and image processing for physico-chemical analysis (pdf)

Deadlines : Final manuscript: February 17th, 2012 Oil & Gas Science and Technology - Revue d'IFP Energies Nouvelles (online journal)

WikiCfP: OGST-SIP-PCA

Computer tools for buddies

Chuck Norris keyboard fact

Unary Day

Advances in signal and image processing for physico-chemical analysis

Looking for new frontiers in signal and image processing applications in chemical related analysis? Consider the following call for contributions.

Call for papers: Dossier, Special issue on Advances in signal and image processing for physico-chemical analysis (pdf)

Deadlines - Intent: December 12th, 2011 / Final manuscript: January 8th, 2012 Oil & Gas Science and Technology - Revue d'IFP Energies Nouvelles (online journal)

Opinion on Melancholia

Sparse is compact and in press (special issue)

Sparse is abundant

Decimate Brands of Banded matrices

Cucu fraternel - are there such things as french maths?

Upcoming conferences (concern Fees) - The latent ones

See my very appreciation to Yves Meyer's price

The turn of a friendly card - Train numbering trick

Leurrer ? Détrompez-vous ! - Dompterez-vous l'erreur ?

Upcoming SIVA signal and image conferences - Concern fees

Time is the simplest (non-commutative) thing

Dimension-reduction, High-dimensional problems and solutions, Workshop, June 2010

Minotaure, tu dois finir ta thèse (again)

Deadlines : Final manuscript: February 17th, 2012

Oil & Gas Science and Technology - Revue d'IFP Energies Nouvelles (online journal)

Deadlines - Intent: December 12th, 2011 / Final manuscript: January 8th, 2012

Oil & Gas Science and Technology - Revue d'IFP Energies Nouvelles (online journal)