2014-01-01 How Airplanes Fly: A Physical Description of Lift

  • http://www.allstar.fiu.edu/aero/airflylvl3.htm
  • quote
     - The amount of air diverted by the wing is proportional to the speed of the wing and the air density.
     - The vertical velocity of the diverted air is proportional to the speed of the wing and the angle of attack.
     - The lift is proportional to the amount of air diverted times the vertical velocity of the air.
     - The power needed for lift is proportional to the lift times the vertical velocity of the air.
    
    Now let us look at some situations from the physical point of view and from the perspective of the popular explanation.
    
     - The plane’s speed is reduced. The physical view says that the amount of air diverted is reduced so the angle of attack is increased to compensate. The power needed for lift is also increased. The popular explanation cannot address this.
     - The load of the plane is increased. The physical view says that the amount of air diverted is the same but the angle of attack must be increased to give additional lift. The power needed for lift has also increased. Again, the popular explanation cannot address this.
     - A plane flies upside down. The physical view has no problem with this. The plane adjusts the angle of attack of the inverted wing to give the desired lift. The popular explanation implies that inverted flight is impossible.

2013-11-12 craac


craac 2013

https://crac.dsi.cnrs.fr/image/logo_cnrs.gif

Compte rendu annuel d'activité des chercheurs du CNRSAnnée 2012 - 2013

Identité


Nom (nom de jeune fille)

PERRINET

Prénom

Laurent

Date de naissance

23/02/1973

Grade

CR1

N° d'agent

00024609

Téléphone

04 91 32 40 44

Télécopie

04 91 32 40 56

Adresse électronique

laurent.perrinet@univ-amu.fr

Section(s) du Comité National

7

Département scientifique

Institut des sciences biologiques

Délégation régionale

Provence et Corse

Affectation


Intitulé de l'unité

Institut de Neurosciences de la Timone

Code unité

UMR7289

Directeur

Guillaume MASSON

Adresse électronique du directeur

guillaume.masson@univ-amu.fr

Adresse

INT - 27 boulevard Jean Moulin

13385 MARSEILLE CEDEX 05

France

Téléphone

04 91 32 40 10

Télécopie

Délégation

Provence et Corse

Site Web

Distinction(s)


Qualification


Habilitation à diriger des recherches

non

Doctorat d'Etat

non

Doctorat

oui

Année d'obtention

2003

Qualification "Maître de conférences"

non

Qualification "Professeur"

non

Période d'inactivité


Mobilité(s) antérieure(s)


Activités de recherche développées


Rattachement à(aux) activité(s) de recherche de l'unité UMR7289

Intitulé d'activité

Date fin du rattachement

Inférence et Comportement visuel - InViBe

Mots clés des sections/CID du Comité national


Section 26 : Modélisation des processus cognitifs et neurosciences computationnelles

Points forts de vos activités de recherche et /ou informations complémentaires


Mon objectif de recherche est d’étendre la compréhension des modèles des facultés cognitives sous la forme de réseaux de neurones impulsionnels qui réalisent des algorithmes de perception visuelle. En effet, les brèves impulsions du potentiel de membrane se propageant au fil des neurones sont une caractéristique universelle des systèmes nerveux et permettent de construire des modèles événementiels efficaces de traitement dynamique de l’information. Dans un but fonctionnel, je désire notamment implanter dans ces modèles des stratégies d’inférence grâce à des mécanismes d’apprentissage auto-organisés fixant les relations spatio-temporelles entre les neurones. Dans le cadre du projet BrainScaleS, nous envisageons la création de nouveaux types d'algorithmes basés sur ces recherches.

Publication(s), parue(s) ou sous presse, dans des revues à comité de lecture


Référence

Bernhard A. Kaplan, Anders Lansner, Guillaume S. Masson, Laurent U. Perrinet. Anisotropic connectivity implements motion-based prediction in a spiking neural network. Front. Comput. Neurosci. 7:112. , 2013

Claudio Simoncini, Laurent U. Perrinet, Anna Montagnini, Pascal Mamassian, Guillaume S. Masson. More is not always better: dissociation between perception and action explained by adaptive gain control. Nature Neuroscience, 2012.

Guillaume S. Masson, Laurent U. Perrinet. The behavioral receptive field underlying motion integration for primate tracking eye movements. Neuroscience and biobehavioral reviews, 2012.

Karl Friston, Rick A. Adams, Laurent Perrinet, Michael Breakspear. Perceptions as Hypotheses: Saccades as Experiments, URL . Frontiers in Psychology, 3, 2012

Laurent U Perrinet et al. Motion-based prediction is sufficient to solve the aperture problem. Neural Computation 2012 24 10 2726-50

Laurent U. Perrinet, Rick A. Adams, Karl Friston. Active Inference, eye movements and oculomotor delays. Biological Cybernetics, 2013 in press.

Mina A. Khoei, Laurent U. Perrinet, Guillaume S. Masson. Motion-based prediction explains the role of tracking in motion extrapolation . Journal of Physiology - Paris, 2013

N. Voges, L. Perrinet. Complex dynamics in recurrent cortical networks based on spatially realistic connectivities . Frontiers in Computational Neuroscience, 6, 2012

Paula Sanz Leon et al. Motion clouds: model-based stimulus synthesis of natural-like random textures for the study of motion perception. Journal of Neurophysiology 2012 107 11 3217-26

Rick A. Adams, Laurent U. Perrinet, Karl Friston. Smooth Pursuit and Visual Occlusion: Active Inference and Oculomotor Control in Schizophrenia, URL . PLoS ONE, 7(10):e47502+, 2012

Publication(s), parue(s) ou sous presse, dans des revues sans comité de lecture


Ouvrage(s) ou chapitre(s) d'ouvrage(s), paru(s) ou sous presse


Référence

Rodrigo Nava, J. Victor Marcos, Boris Escalante-Ram\'\irez, Gabriel Crist\'obal, Laurent U. Perrinet, Ra\'ul S. J. Estépar. Advances in Texture Analysis for Emphysema Classification. 8259:214--221, 2013

Participation à des manifestations scientifiques


Manifestation

20 years of the CerCo

Type de manifestation

Workshop ( international )

Lieu

Toulouse ( FRANCE )

Durée

2 (jour(s))

Intervention(s)

Edge co-occurrences and categorizing natural images par Laurent Perrinet, David Fitzpatrick, James A. Bednar.
Communication orale

Manifestation

3rd BrainScaleS Plenary Meeting - Friday, March 21st, 2013

Type de manifestation

Workshop ( international )

Lieu

Marseille ( FRANCE )

Durée

2 (jour(s))

Intervention(s)

Why methods and tools are the key to artificial brain-like systems par Laurent U. Perrinet
Communication orale

Manifestation

7th Japanese-French Frontiers of Science Symposium

Type de manifestation

Conférence ( international )

Lieu

Kyoto ( Japon )

Durée

5 (jour(s))

Intervention(s)

Laurent U. Perrinet, Rick A. Adams, Karl Friston. Active inference, eye movements and oculomotor delays. . In The 7th Japanese-French Frontiers of Science Symposium., 2013. par Laurent U. Perrinet, Rick A. Adams, Karl Friston
Affiche/poster

Manifestation

CNS*2013

Type de manifestation

Conférence ( international )

Lieu

Paris ( FRANCE )

Durée

5 (jour(s))

Intervention(s)

Laurent U. Perrinet, Rick A. Adams, Karl Friston. Active inference, eye movements and oculomotor delays., URL . In CNS 2013, Paris., 2013 abstract. par Laurent U. Perrinet, Rick A. Adams, Karl Friston
Affiche/poster

Mina A. Khoei, Giacomo Benvenuti, Frederic Chavane, Laurent U. Perrinet. Motion-based prediction and development of the response to an 'on the way' stimulus. 2013. par Khoei
Affiche/poster

Manifestation

Vision Science Society

Type de manifestation

Conférence ( international )

Lieu

Naples ( Etats-Unis )

Durée

6 (jour(s))

Intervention(s)

How and why do image frequency properties influence perceived speed?, par Andrew Meso, Claudio Simoncini, Laurent U. Perrinet, Guillaume S. Masson.

Measuring speed of moving textures: Different pooling of motion information for human ocular following and perception. par Claudio Simoncini, Laurent U. Perrinet, Anna Montagnini, Guillaume S. Masson.

Activité éditoriale


Type d'intervention

Rapporteur/Relecteur dans des revues

Type de document

Revues

Informations complémentaires

IEEE TIP

Type d'intervention

Rapporteur/Relecteur dans des revues

Type de document

Revues

Informations complémentaires

Neural Networks

Type d'intervention

Rapporteur/Relecteur dans des revues

Type de document

Revues

Informations complémentaires

PLoS Computational Biology

Type d'intervention

Rapporteur/Relecteur dans des revues

Type de document

Ouvrage

Informations complémentaires

Journal of Vision

Type d'intervention

Rapporteur/Relecteur dans des revues

Type de document

Informations complémentaires

Neurocomputing

Type d'intervention

Rapporteur/Relecteur dans des revues

Type de document

Informations complémentaires

Conférence NeuroComp 2011

Type d'intervention

Rapporteur/Relecteur dans des revues

Type de document

Informations complémentaires

Journal of Physiology (Paris)

Type d'intervention

Rapporteur/Relecteur dans des revues

Type de document

Autres

Informations complémentaires

Neural Computation

Type d'intervention

Rapporteur/Relecteur dans des revues

Type de document

Revues

Informations complémentaires

Evolving Systems

Type d'intervention

Rapporteur/Relecteur dans des revues

Type de document

Revues

Informations complémentaires

Circuits, Systems and Signal Processing

Séjour(s) dans d'autres laboratoires


Mission(s) sur le terrain


Formation personnelle


Collaborations


Organisme partenaire

INRIA

Pays

FRANCE ( Europe )

Unité partenaire

Odyssee

Intitulé

Sophia

Cadre de la coopération

AUTRE - FACETS

Nature de l'activité

Organisme partenaire

Peyré

Pays

FRANCE ( Europe )

Unité partenaire

CEREMADE

Intitulé

Collaboration sur la création de textures aléatoires.

Cadre de la coopération

Nature de l'activité

Participation à un réseau

Organisme partenaire

University Heidelberg

Pays

Allemagne ( Europe )

Unité partenaire

BrainScaleS

Intitulé

BrainScaleS

Cadre de la coopération

AUTRE - BrainScaleS

Nature de l'activité

Participation à un réseau

Organisme partenaire

University Ulm

Pays

Allemagne ( Europe )

Unité partenaire

NeuroInformatics

Intitulé

Perception of Motion

Cadre de la coopération

Nature de l'activité

Organisme partenaire

Wellcome Trust Centre for Neuroimaging

Pays

Royaume-Uni ( Europe )

Unité partenaire

Karl Friston

Intitulé

FreeMove, a free-energy approach to eye movements

Cadre de la coopération

AUTRE - projet de MAD accepté scientifiquement, refusé administrativement. Remplacé par une mission longue durée.

Nature de l'activité

mission longue durée

Encadrement et animation scientifique


Chercheurs

CNRS

Enseignement supérieur

Autres EPST

Autres

Total

0

0

0

2
Thésarde en CDD sur contrat FACETS-ITN Post-doc en CDD sur contrat BRAINSCALES

2

Doctorants

Thèse

Doctorants étrangers

Doctorants ayant soutenu une thèse

Total

Direction

Codirection

1

0

1

0

1

IT

Stagiaires

IT CNRS

IT non CNRS

Total

Master 2

Licence, master 1

Ecole d'ingénieur

IUT

Autre

Total

0

0

0

2

0

0

0

1

3

Animation scientifique

* Projet artistique en collaboration avec Etienne Rey (artiste plasticien - friche Belle de Mai) dans le cadre de Marseille Provence capitale européenne de la culture 2013. Exposition à la fondation Vasarely (Aix-en-Provence) * Participation au réseau NeuroComp.fr

Enseignement


Valorisation et partenariat


Vulgarisation


Type d'information

Intitulé

Type de participation

Exposition

projet "TROPIQUE", label "Marseille-Provence capitale européenne de la culture 2013"

Conseil scientifique

Administration de la recherche


  • Management et gestion

Membre élu CLAS GLM de Marseille-Joseph Aiguier/Timone

2013-11-08 homebrew cask (level 0): contributing a new cask

Read more…

2013-11-04 SparkleShare on a QNAP

  • SparkleShare is a great alternative to DropBox
  • Fetch the Dazzle script on https://github.com/hbons/Dazzle
    curl https://raw.github.com/hbons/Dazzle/master/dazzle.sh   --output /usr/bin/dazzle && chmod +x /usr/bin/dazzle
  • set-up variables:
    export DAZZLE_USER=admin
    export DAZZLE_HOME=/share/Multimedia/dazzle
  • do it:
    dazzle setup
    dazzle create pool # a first project
    dazzle create-encrypted passwords # this one is completely encrypted on the server side and before the files leave the client

2013-07-08 Useful numbers

Units

  • Radiometric units represent physical energy (e.g., radiance has units of watts sr-1 . m-2 )
  • Colorimetric units adjust radiometric units for visual wavelength sensitivity (e.g. luminance has units of cd m-2 ); scotopic units are proportional to rod absorptions; photopic luminance units are proportional to a weighted sum of the L and M cone absorptions
  • Typical ambient luminance levels (in cd m-2): starlight 10-3; moonlight 10-1 ; indoor lighting 102 ; sunlight 105; max intensity of common CRT monitors, 102
  • One Troland (Td) of retinal illumination is produced on the retina when the eye looks at a surface of 1 cd / m2 through a pupil of area 1 mm2.
  • Lens focal length: f (meters); lens power = 1/f (diopters)
  • Conversion of linear units (X) to decibels: Y = 20 log10(X); a change of 0.3 log10 units is a factor of 2, or 6 dB

Image Formation

  • The eyes are 6 cm apart and half-way down the head
  • Visual angle of the sun or moon = 0.5 deg
  • At arm’s length: thumbnail = 1.5 deg; thumb joint= 2.0 deg; fist = 8-10 deg; index's thumbnail = 1 deg
  • Monocular visual field measured from central fixation: 160 deg (w) x 175 deg (h)
  • Binocular visual field measured from central fixation: 200 deg (w) x 135 deg (h)
  • Region of binocular overlap: 120 deg (w) x 135 deg (h)
  • Range of pupil diameters: 2mm -8mm.
  • Refractive indices: air 1.000; glass 1.520; water 1.333; cornea 1.376
  • Optical power (diopters): cornea, 43; lens, 20 (relaxed); whole eye, 60
  • Change in power due to accommodation, 8 diopters
  • Axial chromatic aberration over the visible spectrum: 2 diopters

Retina

  • Retinal size: 5 cm x 5 cm; 0.4 mm thick
  • One degree of visual angle = 0.3 mm on the retina
  • Number of cones in each retina: 5 x 10^6
  • Number of rods in each retina: 10^8
  • Diameter of the fovea: 1.5 mm (5.2 deg); rod-free fovea: 0.5 mm (1.7 deg); foveola (rod-free, capillary-free fovea): 0.3 mm (1 deg); size of the optic nerve head: 1.5 mm x 2.1 mm (5 deg (w) x 7 deg (h)) location of the optic nerve head: 15 deg nasal
  • Peak cone density: 1.6 x 105 cones/mm2;
  • Foveal cone size: 1-4 mu (diameter) x 50-80 mu (length); extrafoveal cone size: 4-10 mu (diameter) x 40 mu (length)
  • Size of rods near fovea: 1 mu (diameter) x 60 mu (length)
  • S cone spacing (foveal): 10 arc min
  • L and M cone spacing (foveal): 0.5 arc min
  • Number of (L + M) cones / Number of S cones = 14 (though the ratio may be higher in the foveola)
  • 1.5 10^6 optic nerve fibers/retina; ratio of receptors to ganglion cell in fovea 1:3; ratio of receptors to ganglion cells for whole retina, 125:1

Cortex

  • Area of entire cortex: 1.3 x 105 mm2; 1.7 mm thick
  • Total number of cortical neurons: 1010; density: 105 neurons / mm3
  • Synapses: 5 x 108 synapses / mm3 4 x 103^ synapses/neuron;
  • Axons: 3 kilometers / mm^3
  • Number of corpus callosum fibers: 5 x 108
  • Number of macaque visual areas: 30
  • Size of each area V1: 3cm by 8 cm
  • Half of area V1 represents the central 10 deg (2% of the visual field)
  • Width of a human ocular dominance column 0.5-1.0 mm; width of a macaque ocular dominance column 0.3 mm”>.

Sensitivity

  • Minimum number of absorptions for: scotopic detection 1-5; detectable electrical excitation of a rod 1; photopic detection 10-15
  • The number of photoisomerisations per rod (per sec?) required to saturate the retinal rod circuit.
  • Following exposure to a sunny day, dark adaptation to a moonless night involves: 10 minutes (photopic); 40 minutes (scotopic); change in visual sensitivity 6 log10 units
  • Highest detectable spatial frequency at high ambient light levels, 50-60 cpd; low ambient light levels, 20-30 cpd
  • The contrast threshold (Delta L / L) for a static edge at photopic luminances is 1%.
  • Highest detectable temporal frequency: high ambient large field, 80 Hz; low ambient, large field 40 Hz.
  • Typical localization threshold: 6 arc sec (0.5 mu on the retina)
  • Minimum temporal separation needed to discriminate two small, brief light pulses from a single equal-energy pulse: 15-20 ms
  • Stereoscopic depth discrimination: step threshold, 3 arc sec; point threshold, 30 arc sec

Color

  • Visible spectrum: 370-730 nm
  • Peak wavelength sensitivity: 507nm (scotopic) and 555 nm (photopic)
  • Spectral equilibrium hues: 475 nm (blue), 500 nm (green), 575 nm (yellow), no spectral equilibrium red
  • Number of basic English color names: 11
  • Incidence of: anomalous trichromacy, 10-2 (male), 10-4 (female); protanopia and deuteranopia, 10-2 (male), 10-4 (female); tritanopia, 10-4; rod monochromacy, 10-4; cone monochromacy, 10-5

2013-06-12 updating to mactex (texlive for mac), version 2013

  • mactex is not there yet, but pre-relaeses are.
  • you can install the package from this script, or more simply
    wget http://ctan.ijs.si/mirror/tlpretest/mactex-2013.pkg # pre-release of TexLive 2013
    sudo installer -pkg mactex-2013.pkg -target /
  • to update your resource location to update packages, use
    sudo tlmgr option location  http://ftp.math.utah.edu/pub/texlive/tlpretest/
  • to upgrade
    sudo tlmgr update --self
    sudo tlmgr update --all

2013-05-14 dropping owncloud

  • since about 6 months, I was using ownCloud as a remplacement of dropbox, but I had unfortunately lots of problems and finally decided to drop wasting time on maintaining it.
  • it is certainly a useful service, but there are certainly simpler things to use to sync files accross computers and implement "your own cloud". here, I give some reasons for my choice and hope they may be useful for further developpment of owncloud or any other alternative to dropbox:
    • first of all, you need an efficient file syncing. it is dangerously buggy in owncloud:
      1. generates zillions of conflict files, takes ages to sync a folder with lots of files.
      2. the client happened to delete some files with no warning
      3. gives little feedback on how things are processed (the info dialog in client 1.2.5 is not functional). it took me a while to find a way to get some logfile (by calling the client with the --logfile argument) - but it is not documented elsewhere. the icons and error codes are not always informative.
      4. does not compile on snow leopard / 32-bit.
    • the server is simple to install but is too shiny over-the-top compared to its raw functionality.
      1. the upgrade process was rarely smooth due to "maintenance problems" related to the database (one day wasted for 5.0.4 > 5.0.5). this hints me that there may be security issues that are unresolved.
      2. the media server / photo gallery is merely useless
    • I bought the apps for iOS and android, and they are a joke
      1. you need to synchronize all your files, no choice is possible - thus it is just not useful and I could never access any file off-line
      2. uploading photos is buggy, videos are ignored
    • the ecosystem:
      1. based on a set of developers (some part of a company) and a set of users complaining about bugs that get closed is not reassuring
      2. the motto "you have a dropbox problem" is not pushing issues forward. certainly when comparing to the quality of the dropbox service
  • alert everything I say here is with a QNAP server (and I am not a sysdamin), so it is certainly partly my fault.