July 23, 2010

The turn of a friendly card - Train numbering trick

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:

July 21, 2010

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

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].

July 19, 2010

Upcoming SIVA signal and image conferences - Concern fees

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.

July 10, 2010

Time is the simplest (non-commutative) thing

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).

July 3, 2010

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

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",

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

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

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

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

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,

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

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

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

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

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

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.