The Age of Information

Nathaniel J. C. Libatique, Ph.D.

Science 10, Topic 4: Technological Underpinnings

IngredientsIngredients

Broadband wireline transmissionBroadband wireline transmission Wireless transmissionWireless transmission Digitization of the Analog WorldDigitization of the Analog World Democratization of contentDemocratization of content

http://www.analog-girl.net, http://blog.analog-girl.net/

http://www.time.com/time/specials/2007/article/1,28804,1704856_1704855_1704824,00.html

Beacon Hills of GondorBeacon Hills of Gondor

ww.tuckborough.net/images/beaconhills.jpg

In the film version of The Lord of the Rings, the signal beacon in Minas Tirith was lit by Pippin Took contrary to Denethor's orders.

A semaphore telegraph, optical telegraph, shutter telegraph chain, Chappe telegraph, or Napoleonic semaphore is a system of conveying information by means of visual signals, using towers with pivoting shutters, also known as blades or paddles. Information is encoded by the position of the mechanical elements; it is read when the shutter is in a fixed position.

http://en.wikipedia.org/wiki/Optical_telegraph

The Optical TelegraphThe Optical Telegraph

Semaphore vs. TelegraphSemaphore vs. Telegraph The semaphore system was cleverly designed, and provided a The semaphore system was cleverly designed, and provided a

strategic advantage for France in a difficult time. However, it strategic advantage for France in a difficult time. However, it was almost 30 times more expensive per message than the was almost 30 times more expensive per message than the electric telegraph. Here's a brief breakdown using (inflation-electric telegraph. Here's a brief breakdown using (inflation-adjusted to unknow date by unknown method) US$[citation adjusted to unknow date by unknown method) US$[citation needed]:needed]:

Semaphore line, 120 miles (Paris to Lille)Semaphore line, 120 miles (Paris to Lille) 15 towers ($1,500,000), At least 15 full-time operators 15 towers ($1,500,000), At least 15 full-time operators

($450,000/year), operates at most ten hours a day.($450,000/year), operates at most ten hours a day. Sends roughly 2 words per minute (1 symbol per Sends roughly 2 words per minute (1 symbol per

minute, at 2 symbols per phrase, using the minute, at 2 symbols per phrase, using the efficient directors' codebook).efficient directors' codebook).

* Cost to send one word one mile (1.6 km), at 10% markup: * Cost to send one word one mile (1.6 km), at 10% markup: $0.0114$0.0114

Electric Telegraph line, 120 miles (190 km)Electric Telegraph line, 120 miles (190 km)

At least six full-time operators ($180,000/year)At least six full-time operators ($180,000/year) Poles, right-of-way, wires, installation: $15,000/mile, Poles, right-of-way, wires, installation: $15,000/mile,

($1,800,000)($1,800,000) Operates 24 hours a day.Operates 24 hours a day. Sends 15 words per minute (includes breaks for the operators).Sends 15 words per minute (includes breaks for the operators). Cost to send one word one mile (1.6 km), at 10% markup: Cost to send one word one mile (1.6 km), at 10% markup:

$0.0003809$0.0003809

http://en.wikipedia.org/wiki/Optical_telegraph

Fields and WavesFields and Waves

f = c

Carrier FrequenciesCarrier Frequencies

Wireless information is carried on top of Wireless information is carried on top of a a ““carrier frequencycarrier frequency””

The higher the carrier frequency, the The higher the carrier frequency, the more information can be sent via this more information can be sent via this carriercarrier

Light waves have frequencies in the Light waves have frequencies in the hundreds of THz! (100 THz = 100 x 10hundreds of THz! (100 THz = 100 x 1012 12

Hz = 100,000 GHz, one hundred Hz = 100,000 GHz, one hundred thousand times the carrier frequencies thousand times the carrier frequencies for mobile wireless (about 1 GHz)for mobile wireless (about 1 GHz)

Bandwidth increases Bandwidth increases with carrier frequencywith carrier frequency

The larger the carrier The larger the carrier frequency ffrequency fcc the greater the greater its bandwidth its bandwidth f or B.f or B.

Nature of LightNature of Light

ReflectionReflection RefractionRefraction DiffractionDiffraction InterferenceInterference

Is light a wave or a particle?Answer: It is BOTH.

Particle: ReflectionParticle: Reflection

Incident angle = Reflection angle

True locally, even for curved surfacesSymmetric Property

Particle: RefractionParticle: Refraction SnellSnell’’s Law: ns Law: n11 sin sin 11 = n = n2 2 sin sin 22

FermatFermat’’s Principle (Least Time)s Principle (Least Time)

In the denser medium, lightbends towardsthe normal

n1

n2

11

22

TIR: TIR: Total Total

Internal Internal ReflectiReflecti

ononRefraction

CriticalAngle

TIR

http://www.fas.harvard.edu/~scdiroff/lds/LightOptics/FishTankTIR/FishTankTIR.html

Creating a Light GuideCreating a Light Guide

c

Critical Angle c

Propagation in MMF Propagation in MMF FiberFiber

MMF = multimode fiber

Lowest Loss in the Lowest Loss in the InfraredInfrared

Diffraction of Water Diffraction of Water WavesWaves

As the aperture size decreases …

Water waves are like rays when aperture is large with respect to wavelength

Diffraction of Water Diffraction of Water WavesWaves

The incident wave diffracts out of the aperture as if it was a point source …Light “rays” also act like waves in similar

diffraction experiments!

Wave: InterferenceWave: Interference

Interfering water waves in a ripple tank

Wave: Doppler EffectWave: Doppler Effect

Blue Shift

Red Shift

Red ShiftRed Shift

http://en.wikipedia.org/wiki/Redshift

Absorption lines in the optical spectrum of a supercluster of distant galaxies (right), as compared to absorption lines in the optical spectrum of the Sun (left).

Fiber Modes: Light Ray Fiber Modes: Light Ray PicturePicture

Fiber ModesFiber Modes

LP01

LP03

LP11

LP13

LP21 LP22LP41

LP17 16LP28 5

Fiber ModesFiber Modes

Analog SignalAnalog Signal

t

s(t)

Quantization and Quantization and SamplingSampling

s(t)

t000

001

010

011

100

101

110

111

s(t)

t000

001

010

011

100

101

110

111

Quantization and Quantization and SamplingSampling

001 001 011 011 100 101 111 110 100 100 011 010 100 010 001 010

Quantization and Quantization and SamplingSampling

001 001 011 011 100 101 111 110 100 100 011 010 100 010 001 010

s(t)

ts(t)

t

The Signal is The Signal is Reconstructed at the Reconstructed at the

Receiver!Receiver!001 001 011 011 100 101 111 110 100 100 011 010 100 010 001 010

Digital to Analog Conversion

Original Analog Signal

AliasingAliasing

One has to sample/digitize the original One has to sample/digitize the original analog signal at a rate at least twice the analog signal at a rate at least twice the frequency of the signal – the Nyquist frequency of the signal – the Nyquist criterion. Otherwise, if we sample too criterion. Otherwise, if we sample too slowly, when the digital signal is slowly, when the digital signal is subsequently reconstructed we will subsequently reconstructed we will come up with an erroneous signal.come up with an erroneous signal.

Nyquist Criterion: f.sampling < f.maxNyquist Criterion: f.sampling < f.max

• 200 page novel (100,000 Words); Holy Bible (775,000 Words)For 5 letters/word and 7 bits/character = 3

Mbits1 sec transfer of information 3.5 Mb/s

• Voice CommunicationsIntelligible speech with 300 Hz to 3.5 kHzSample at 8 kHz with 8 bits/sample 64 kb/s

• Compact DiskDynamic range of >80 dB and 20 kHz

bandwidthSample at 44 kHz with 14 bits per sample

640 kb/sFrom G. Tangonan, 1988 First SEA Laser School, UP, Diliman

Digital Channel Digital Channel RequirementsRequirements

• Video Channel55 to 65 dB S/N needed for good qualitySampling at 4x color subcarrier (4 x 4.43 MHz)

8 bits/sample at 17.7 MHz 142 Mb/sWith compression: 5 bits/sample at 8.86 MHz

44.3 Mb/s• HDTV 720p: 720 lines by 1280 columns = 1

Mpixel• High Speed Computer I/O

32 lines at 25 MHz typicalmultiplexing leads to 800 Mb/s

• High Speed Computer I/O

Digital Channel Digital Channel RequirementsRequirements

• E1 - leased line, 2 Mb/s• DS3 - pt. to pt. private line,

44.7Mb/s• STM-1 - 155.52 Mb/s• Fast Ethernet - 100 Mb/s• Gigabit Ethernet - 1 Gb/s• Fiber Channel - storage area

networks, 1 Gb/s• Wifi 802.11n - 248 Mbps max• Wifi 802.11g – 54 Mbps

Line Rates and ProtocolsLine Rates and Protocols

Digital AdvantagesDigital Advantages

Less Susceptible to Noise: Less Susceptible to Noise: boolean boolean decisions, error detection and correctiondecisions, error detection and correction

Circuits easier to fabricate at larger Circuits easier to fabricate at larger scalescale

Higher fidelity, qualityHigher fidelity, quality Compatible with computing platformsCompatible with computing platforms More easily encryptedMore easily encrypted

Google’s Daily Doodle for27 April 2009

Number as AbstractionNumber as Abstraction

Quantization ErrorQuantization Error Bit Stream vs. AnalogBit Stream vs. Analog Abstraction into a Abstraction into a

series of Yes and No series of Yes and No bits of informationbits of information

““The shadow of the The shadow of the shadow of the shadow of the shadow…shadow…””

Real or Abstract?Real or Abstract?Who you areWho you are

FacebookFacebookDigital passportsDigital passports

How much you own or are worthHow much you own or are worthWhether you exist or notWhether you exist or not

Birth certificatesBirth certificatesCitizenshipCitizenship

India Fingerprinting, Iris Scanning Over India Fingerprinting, Iris Scanning Over One Billion PeopleOne Billion People

The Indian government is ramping up The Indian government is ramping up efforts to fingerprint and iris scan the efforts to fingerprint and iris scan the entirety of its 1.2 billion citizens in an entirety of its 1.2 billion citizens in an ambitious scheme to issue national ID cards ambitious scheme to issue national ID cards with biometric details. The plan has so far with biometric details. The plan has so far already enrolled 110 million people and already enrolled 110 million people and issued 60 million numbers, with the aim of issued 60 million numbers, with the aim of enrolling 200 million by this March and 600 enrolling 200 million by this March and 600 million by 2014.million by 2014.

VEIN ScanningVEIN Scanning

Also see: spectrum.ieee.org/computing/software/bitcoin-the-cryptoanarchists-answer-to-cash/0

Thermodynamics: 1Thermodynamics: 1stst and and 22ndnd Laws Laws

Energy is conserved, it is neither Energy is conserved, it is neither created nor destroyedcreated nor destroyed

Entropy always increases until it Entropy always increases until it reaches a maximum value (Disorder reaches a maximum value (Disorder vs. Order)vs. Order)

Time’s ArrowTime’s Arrow

Second Law of Second Law of ThermodynamicsThermodynamics

http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/seclaw.html

Paradox: MaxwellParadox: Maxwell’’s s DemonDemon

James Clerk Maxwell

Information is Information is Energy!Energy!

Einstein and Szilard

The measurement process, in which the The measurement process, in which the demon acquires a single “bit” of information demon acquires a single “bit” of information (i.e., the information as to whether an (i.e., the information as to whether an approaching molecule is a slow one or a fast approaching molecule is a slow one or a fast one) requires energy and must produce at one) requires energy and must produce at least as much entropy as is decreased by the least as much entropy as is decreased by the sorting of that molecule into the left or right sorting of that molecule into the left or right side of the box. Thus the entire system, side of the box. Thus the entire system, comprising the box, the molecules, and the comprising the box, the molecules, and the demon, obeys the second law of demon, obeys the second law of thermodynamics.thermodynamics.

Claude shannon: Claude shannon: Information ContentInformation Content

Information has Information has Entropy – the Entropy – the information content information content of a messageof a message

Degree of SurpriseDegree of Surprise I(m) = - log[p(m)]I(m) = - log[p(m)]

http://en.wikipedia.org/wiki/File:Monkey-typing.jpg

Harvard biologist George Church, in his office Wednesday, recently encoded a book he wrote into the genetic molecules of DNA.

FUTURE OF DATA: Encoded in DNA

By ROBERT LEE HOTZ (Wall Street Journal, 16 Aug 2012; http://online.wsj.com)

In the latest effort to contend with exploding quantities of digital data, researchers encoded an entire book into the genetic molecules of DNA, the basic building block of life, and then accurately read back the text.

The experiment, reported Thursday in the journal Science, may point a way toward eventual data-storage devices with vastly more capacity for their size than today's computer chips and drives.

"A device the size of your thumb could store as much information as the whole Internet," said Harvard University molecular geneticist George Church, the project's senior researcher.

In their work, the group translated the English text of a coming book on genomic engineering into actual DNA. DNA contains genetic instructions written in a simple but powerful code made up of four chemicals called bases: adenine (A), guanine (G), cytosine (C) and thymine (T).

Dr. Church keeps a vial of DNA encoded with copies of his latest book

Photos by Kelvin Ma for the Wall Street Journal

DemosDemos

Single slit diffractionSingle slit diffraction Sinusoid + Noise on LabViewSinusoid + Noise on LabView Total Internal ReflectionTotal Internal Reflection Visualizing IR via silicon CCD Visualizing IR via silicon CCD

cameracamera RefractionRefraction AliasingAliasing