Catégorie

Codage des caractères

vignette|alt=Carte rectangulaire beige clair avec dans le sens de la longueur 10 lignes constituées chacune d'une suite de chiffre identique, de 1 à 10. Des perforations verticales font disparaître certains de ces chiffres|Carte perforée à 80 colonnes, sur laquelle est codé le texte de programmation « CALL RCLASS (AAA, 21, NNC, PX3, PX4) ». En télécommunications et en informatique, un jeu de caractères codés est un code qui associe un jeu de caractères abstraits d’un ou plusieurs systèmes d’écriture (comme des alphabets ou des syllabaires) utilisés pour transcrire des langues naturelles avec une représentation numérique pour chaque caractère de ce jeu, ce nombre pouvant lui-même avoir des représentations numériques différentes. Par exemple, le code Morse (qui associe l’alphabet latin à une série de pressions longues et de pressions courtes sur le manipulateur morse du télégraphe) et le code ASCII (qui code les lettres, les chiffres et d'autres symboles comme des entiers codés sur 7 bits) sont des jeux de caractères codés. Il est indispensable, pour l'échange d'information sur l'Internet, par exemple, de préciser le codage utilisé. Ne pas le faire peut rendre un document difficilement lisible (remplacement des lettres accentuées par d'autres suites de caractères connu sous le nom de mojibake). Toutefois, la convergence vers un standard commun devrait enfin répondre à ce problème. Dans certains contextes (en particulier dans les communications et dans l'utilisation de données informatiques), il est important de distinguer un répertoire de caractères, qui est un jeu complet de caractères abstraits qu'un système supporte, et un jeu de caractères codés ou codage de caractères qui spécifie comment représenter un caractère en utilisant un entier. Le codage des caractères est une convention qui permet, à travers un codage connu de tous, de transmettre de l'information textuelle, là où aucun support ne permet l'écriture scripturale. Cela consiste à représenter chaque caractère, par un motif visuel, un motif sonore, ou une séquence abstraite.

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Exercices associés (25)

Oscillator à deux ressorts

A block of mass m is connected to the floor and the ceiling of a room of height h by two springs. The springs have elastic constants k₁ and k₂ and null rest lengths, as indicated on the diagram. Gravity acts on the block. We only consider the block’s vertical motion, along an x-axis pointing downwards with its origin on the ceiling. We neglect the block’s shape, as well as any friction.

Draw, on a diagram, all the forces acting on the block and give their expressions.
Find the differential equ

Suspension d une voiture

A car’s suspension is comfortable when it has a vertical oscillation period that our bodies are used to: the oscillation period of walking, Tu2004=u20040.8u2005s.

Find the spring constant k of the suspension in a car of mass $M = 1540\,{\rm kg}$ .
The car lowers when we place a trunk of mass $m = 70\,{\rm kg}$ in it. Find its vertical displacement.

To make the car more comfortable, we add a shock absorber/dampener that creates a friction force F⃗u2004=u2004u2005−u2005bv⃗_(z), where v⃗_(z)

Boucler la boucle

A stuntwoman attempts to drive her car weighing mg around a vertical looping track of radius R. She enters the track at point P with velocity V⃗_(P) and we assume that she then free-wheels around the track without either braking or accelerating. There is no friction.

Write the car’s equations of motion for the entire loop.
Express the car’s mechanical energy at all points of the loop, and show that the mechanical energy is a simple integral of the motion.
Compute the reaction force from t

Ressort dans une boîte

A closed box of mass M is resting on a table. Inside the box is a marble of mass m, attached to the lid by a spring with spring constant k and rest length l₀. What’s the minimal amplitude A of the marble’s vertical oscillation for the box to lift from the table? We assume l₀ and k to be large enough for the marble to avoid hitting the lid or the table before the box takes off. u2005 Indication: treat both the box and the marble as material points. The box will take of if its bonding force with the table

Equilibre stable

A solide is made up of a truncated straight homogeneous cone, with a circular base of radius R, set on a homogenous half-sphere of radius R and with the same density ρ, as shown on the diagram. The cone opens downwards with an apex half-angle α. Show that the solid is in a stable equilibrium on the horizontal plane if, and only if αu2004>u200430^(o). Hint: With origin O at the junction between both solids on axis z, the center of mass of the cone with volume

\frac{1}{3}\pi hR^2

is at height $z_{G_c}=\fr

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Notebooks associés (16)

Exploring Quantization and Oversampling through One-Bit Music

One-Bit Music[1]¶ In this notebook we will talk about quantization and oversampling and we will do so by taking a trip down memory lane to revisit the early from monophonic square waves, introduce polyphony by way of pulse-width modulation and finish with the basics of sigma-delta quantization. pacman In [1]: import matplotlib import matplotlib.pyplot as plt import numpy as np import scipy.signal as sp from scipy.io import wavfile import IPython In [2]: import sys ! wget -q -O mus

Whistle-Activated Keylock System Implementation

Whistling Keylock[1]¶ In this notebook we will implement a simple "whistle-activated" keylock, that is, an access control system where the password is a pre-defined melody. To program the lock, you record your musical passphrase and then, to open the lock, you whistle it back. Although the implementation will be simple and skip most of the fine details that would be necessary to produce a truly robust system, we need to take into account at least the following points: * The syste

Exploring the Karplus-Strong Algorithm for Sound Synthesis

The Karplus-Strong Algorithm[1]¶

                                      [2]Paolo Prandoni, [3]LCAV, EPFL

The Karplus-Strong algorithm is a simple method to generate synthetic sounds with arbitrary pitch. In this notebook we will explore a few variations of the method to illustrate some basic notions of discrete-time signal processing. In [1]: %matplotlib inline import matplotlib import matplotlib.pyplot as plt import numpy as np import IPython In [2]: plt.rcParams["figure.figsize"]

Implementing a Fractional Resampler using Local Lagrange Interpolation

FIR Resampling[1]¶

                                      [2]Paolo Prandoni, [3]LCAV, EPFL

In this notebook we will implement a simple fractional resampler that uses local Lagrange interpolation. The resampler can be used to perform any rational sampling rate change (but beware of aliasing when downsampling!) In [1]: import numpy as np import IPython from scipy.io import wavfile Local Lagrange interpolation[4]¶ To perform resampling we will need to compute subsample values and, in

Powder X-Ray Diffraction Analysis: Exploring Crystal Structures.

XRay Diffraction[1]¶ The purpose of this notebook is to study the powder XRay diffraction spectra of some systems. When the crystal is hit with an XRay wave, the wave is diffracted only for specific case where the Bragg condition is satisfied for one of the lattice planes in the material. For single crystal diffraction, the condition is satisfied only for specific orientation of the crystal, such that the incident ray has the correct

\theta

value for the plane. In powder XRay data, however, any plane ori

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Notebooks associés (16)

Exploring Quantization and Oversampling through One-Bit Music

Whistle-Activated Keylock System Implementation

Exploring the Karplus-Strong Algorithm for Sound Synthesis

The Karplus-Strong Algorithm[1]¶

                                      [2]Paolo Prandoni, [3]LCAV, EPFL

Implementing a Fractional Resampler using Local Lagrange Interpolation

FIR Resampling[1]¶

                                      [2]Paolo Prandoni, [3]LCAV, EPFL

Powder X-Ray Diffraction Analysis: Exploring Crystal Structures.

\theta

value for the plane. In powder XRay data, however, any plane ori

Afficher plus

Exercices associés (25)

Oscillator à deux ressorts

Draw, on a diagram, all the forces acting on the block and give their expressions.
Find the differential equ

Suspension d une voiture

A car’s suspension is comfortable when it has a vertical oscillation period that our bodies are used to: the oscillation period of walking, Tu2004=u20040.8u2005s.

Find the spring constant k of the suspension in a car of mass $M = 1540\,{\rm kg}$ .
The car lowers when we place a trunk of mass $m = 70\,{\rm kg}$ in it. Find its vertical displacement.

To make the car more comfortable, we add a shock absorber/dampener that creates a friction force F⃗u2004=u2004u2005−u2005bv⃗_(z), where v⃗_(z)

Boucler la boucle

Write the car’s equations of motion for the entire loop.
Express the car’s mechanical energy at all points of the loop, and show that the mechanical energy is a simple integral of the motion.
Compute the reaction force from t

Ressort dans une boîte

Equilibre stable

\frac{1}{3}\pi hR^2

is at height $z_{G_c}=\fr

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Codage des caractères

Chattez avec Graph Search

Ranking Items from Discrete Ratings: The Cost of Unknown User Thresholds

From Stone to Standards: A Digital Heritage Interoperability Model for Armenian Epigraphy Within the Leiden and EpiDoc Frameworks

Ranking Items from Discrete Ratings: The Cost of Unknown User Thresholds

From Stone to Standards: A Digital Heritage Interoperability Model for Armenian Epigraphy Within the Leiden and EpiDoc Frameworks