31 October 2007

Henry Rollins despre libertatea internetului

Noi le-am luat-o deja inainte: link.

Trent Raznor despre viitorul industriei muzicale

Radiohead shook the industry earlier this month by releasing a digital version of their latest album and asking fans pay whatever price they believed the album was worth. It was unprecedented move largely because it appeared to address an issue that music industry has largely tried to ignore. Music fans, many of whom obtain songs for free through illegal file sharing, perceive the dollar value of songs as almost nothing. Unless something dramatic occurs, many believe there is a chance a large number of fans will never again be swayed to plunk down money for music. Reznor, 42, said that the music industry is spinning its wheels trying to fight that perception. He said that in the future songs can be a way to entice fans to buy concert tickets and merchandise and he recognized that this may be how musicians make their living. ... "Radiohead is one of my favorite bands," Reznor said. "When they announced they were releasing that album for free, I got dozens of text messages. It gave me goose bumps? It's such an exciting way to sell a record." ... "The greatest thing about the Internet is that everybody is their own distributor," Reznor said. "Being your own distributor is power and the thing that labels once held over artists. The power of getting your message out to an audience is very empowering as an artist. These are exciting times and things are happening that I couldn't imagine just a few years ago." As for the future, well, Reznor fully acknowledges that he--like everybody else in music--is unsure of how things will turn out. But he says he's sure of one thing: the old way of doing business is dead. "I don't know what the future holds," he said. "I don't know what model is going to work. I do know relationships between music labels and artist like myself aren't going well. These days when digital elements come into play labels have dealt with them generally poorly. It has gotten to a place where it couldn't be worse. Their treatment of artists has less sympathy and it's more like 'What can we get out of you.' My only concern has always been that my audience is treated fairly."

27 October 2007

A fost descoperita cea mai simpla masina Turing universala

O masina Turing e un computer idealizat - functioneaza fara erori si are memorie infinita. O masina Turing e universala daca poate face orice fel de calcul posibil. O reprezentare utila a masinilor Turing e urmatoarea: Fiecare rand de pe o foaie de matematica reprezinta starea memoriei masinii la un moment dat - cel mai de sus rand este primul. O patratica poate fi colorata intr-un anumit numar de culori posibile (initial exista o culoare implicita). Capul de citire poate avea si el un anumit numar de stari posibile (x, y, z, ...). O regula este o functie de culoarea patratelului pe care e capul de citire si de starea capului de citire si determina culoarea patratelului de sub capul de citire, noua pozitie a capului de citire relativa la vechea pozitie (capul se muta la stanga sau la dreapta) si noua stare a capului de citire. De exemplu o masina Turing cu 2 culori posibile si cu un cap de citire cu 3 stari posibile (x, y, z) e formata din 3x2=6 reguli. Sunt foarte multe asemenea masini Turing posibile. (Formula generala este (2nk)^nk masini Turing posibile cu n stari ale capului de citire si k culori ale memoriei.) Iata de pilda una:


Un program (algoritm) este un anumit input (un anumit pattern de culori) pe prima linie + pozitia initiala a capului de citire. Una dintre reguli este in mod conventional aleasa sa reprezinte comanda de oprire a programului. Patternul de culori la care s-a ajuns atunci pe ultima linie reprezinta output-ul algoritmului. (Un program care "se blocheaza" e un program care nu ajunge niciodata sa execute regula de oprire.) O masina Turing universala este o masina pe care poate fi implementat orice algoritm posibil - cu alte cuvinte o masina Turing care poate simula orice alta masina Turing. Acum a fost descoperita cea mai simpla masina Turing universala. Se stia ca nu exista nici o masina Turing universala cu 2 culori si 2 stari ale capului de citire - asa ca urmatoarea varianta candidata era 2,3. Exista 2,985,984 asemenea masini Turing posibile. In 2002, Stephen Wolfram a speculat ca poate urmatoarea masina este universala:


In primavara anului asta a anuntat un premiu de 25,000 de dolari celui care demonstreaza ca masina asta Turing este universala sau demonstreaza ca nu e universala. Premiul a fost luat acum de un student de 20 de ani, Alex Smith, din Birmingham.
I telephoned Alex Smith a few days ago, to tell him that we were finally convinced that he'd solved the problem and earned the prize. I asked him why he'd worked on it. He said he'd seen it as a nice puzzle. That at first he was pretty sure the Turing machine's behavior was simple enough that he could prove that it wasn't universal. But then, as he studied it, he realized that there were little bits of behavior that were more complicated. And it was with these that he managed to show universality. ... It's a very satisfying way to spend $25,000.
Asta s-ar putea sa fie un rezultat foarte important. De pilda daca Wolfram are dreptate ca universul e un calculator, regulile acestei masinii Turing sunt intr-un anumit sens legile naturii la nivelul cel mai profund (ramane sa mai determinam "doar" care este semnificatia culorilor si a starilor capului de citire). Iata care e rezultatul functionarii acestei masini Turing plecand de la un input uniform alb (fara definirea unei stari de oprire a programului):

Prosti, dar multi

Adevarul despre politicienii romani

Treacherous Rage-Addicted Investigator-Abducting, Nun-Beheading Abomination from the Sunless Earth

Transforming Artificial Replicant Intended for Calculation, Efficient Assassination and Nocturnal Utility

General Electronic Observation and Accurate Nullification Android

Sinister Terror from the Ominous Legendary Oasis

Vicious, Abhorrent Demon Inflamed by Madness

Bloodthirsty, Evil Creature from the Arcane Legendary Isle

Playful One Needing Touches and Affection

Sexy Temptress Offering Intense Caresses and Affection

26 October 2007

Iluzie optica - Change blindness

Change blindness consta in faptul ca in anumite conditii, din cauza ca nu esti atent, nu observi diferente foarte mari intre doua fotografii.
A large fraction of traffic accidents are of the type "driver looked but failed to see". Here, drivers collide with pedestrians in plain view, with cars directly in front of them (the classic "rear-ender"), and even run into trains. (That's right -- run into trains, not the other way around.) In such cases, information from the world is entering the driver's eyes. But at some point along the way this information is lost, causing the driver to lose connection with reality. They are looking but they are not seeing. What's going on? Our findings indicate that the critical factor is attention: To see an object change, it is necessary to attend to it.
Demonstratii: Link (apasa cu butonul din dreapta ca sa selectezi si alte exemple decat ala cu avionul) Si pe alt principiu: 1, 2, 3, 4, 5, 6, 7.

Catedrala Mantuirii Casei Poporului

Propunerea lui Vlad Nanca :)

Despre autentificarea artei :)

25 October 2007

Kevin Kelly - "Ce vrea tehnologia?"

Kevin Kelly indica 5 caracteristici ale vietii: tinde: - sa se raspandeasca peste tot - sa devina din ce in ce mai diversificata - apar forme de viata tot mai specializate la un anumit tip de mediu - apar forme de viata tot mai complexe - co-evolutia (constrangerile sunt date de alte fiinte vii si nu de mediul fizic) devine tot mai importanta Evolutia tehnologica are aceleasi caracteristici.

Ramachandran despre sindromul Capragras, membre fantoma, si creativitate

24 October 2007

Matt Ridley despre cum interactioneaza genele cu mediul

si creeaza natura umana. Include si o descriere genei FOXP2 implicata in capacitatea noastra de a avea limbaj - prima gena de acest fel care a fost descoperita (deocamdata si singura). Link

20 October 2007

Primul robot ucigas: 9 morti, 14 raniti

Cele mai multe sisteme computerizate folosite in armata acum au rolul de a gasi tintele insa in general e nevoie de un om care sa apese pe tragaci. Armata din Africa de Sud s-a gandit sa incerce sa elimine factorul uman complet. Rezultatul: un "accident".
SA National Defence Force spokesman brigadier general Kwena Mangope says the cause of the malfunction is not yet known... Media reports say the shooting exercise, using live ammunition, took place at the SA Army's Combat Training Centre, at Lohatlha, in the Northern Cape, as part of an annual force preparation endeavour. Mangope told The Star that it “is assumed that there was a mechanical problem, which led to the accident. The gun, which was fully loaded, did not fire as it normally should have," he said. "It appears as though the gun, which is computerised, jammed before there was some sort of explosion, and then it opened fire uncontrollably, killing and injuring the soldiers." Other reports have suggested a computer error might have been to blame. Defence pundit Helmoed-Römer Heitman told the Weekend Argus that if “the cause lay in computer error, the reason for the tragedy might never be found."
Mi se pare ca motivul accidentului nu e chiar asa de greu de gasit: cine si-a inchipuit ca e o idee buna sa construiesti roboti ucigasi autonomi?!

14 October 2007

Iluzie optica: spinning silhouette

In ce directie se roteste imaginea de mai jos? Cei mai multi o vad rotindu-se in sensul acelor de ceas. Daca acoperi silueta si te uiti doar la umbra o poti face sa se roteasca si in directia inversa. Dupa o vreme schimbarea sensului de rotatie apare (la intamplare) si daca te uiti la toata imaginea, iar dupa mult "antrenament" o poti face in mod constient sa-si schimbe directia de rotatie. Explicatia pentru iluzie pare sa fie (Rishikesh Dalal):
The reason we experience the illusion is that the mind extrapolates the shadow into a 3-D object. The 3-D object could be either of two mirror images. We just don't know which mirror image to select. In fact, ANY object, regardless of its symmetry or non-symmetry can be transformed by reflection and will produce the same shadow when rotating in the opposite direction as the original. Basically just imagine reflecting the rotating object itself in a mirror - the reflected object will produce the same shadow but will be spinning in the opposite direction to produce the shadow. Our shillouhette is a perfect example of this in action - when spining clockwise, her right arm is outstretched and her head is tilted to her right. When spinning CCW, her left arm is outstretched and her head is tilted to her left. The two objects that we can extrapolate from the shadow are mirror images of each other. Most people see the clockwise rotation initially because we tend to perceive the feet as being closer to the observer when they are lower in the field of vision (as in everyday life).

Stoluri de pasari incredibile

In Anglia (partea interesanta incepe pe la 2:00): In Roma:

04 October 2007

Despre expeditia Cassini spre Saturn

si aterizarea sondei Huygens pe satelitul lui Saturn, Titan. Pamantul fotografiat din sistemul lui Saturn: Tot ce-a facut Cassini: link.

03 October 2007

Cum s-a nascut Dumnezeu

Calota polara de la Polul Nord impinsa de vant

Calota polara de la Polul Nord a scazut dramatic in ultimii ani si mai ales anul asta. Link. Deja e tot mai clar ca nu poate fi vorba de o variatie naturala. Se pare ca anul asta topirea a fost mai mare decat se asteptau oamenii de stiinta pentru ca vantul a impins calota glaciara!
Complicating the picture, the striking Arctic change was as much a result of ice moving as melting, many say. A new study, led by Son Nghiem at NASA’s Jet Propulsion Laboratory and appearing this week in Geophysical Research Letters, used satellites and buoys to show that winds since 2000 had pushed huge amounts of thick old ice out of the Arctic basin past Greenland. The thin floes that formed on the resulting open water melted quicker or could be shuffled together by winds and similarly expelled, the authors said. ... While experts debate details, many agree that the vanishing act of the sea ice this year was probably caused by superimposed forces including heat-trapping clouds and water vapor in the air, as well as the ocean-heating influence of unusually sunny skies in June and July. Other important factors were warm winds flowing from Siberia around a high-pressure system parked over the ocean. The winds not only would have melted thin ice but also pushed floes offshore where currents and winds could push them out of the Arctic Ocean.
Se estimeaza ca in vreo 20-30 de ani vor putea exista curse regulate peste Oceanul Arctic.
Many Arctic researchers warned that it was still far too soon to start sending container ships over the top of the world. “Natural variations could turn around and counteract the greenhouse-gas-forced change, perhaps stabilizing the ice for a bit,” said Marika Holland, of the National Center for Atmospheric Research in Boulder, Colo. But, she added, that will not last. “Eventually the natural variations would again reinforce the human-driven change, perhaps leading to even more rapid retreat,” Dr. Holland said. “So I wouldn’t sign any shipping contracts for the next 5 to 10 years, but maybe the next 20 to 30.”