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  • Urban 19:37 on 25 Sep. 2010 Permalink |  

    OK? 

    Kako nekomu pokažeš, da je vse OK?

    Lahko takole:

    Thumbs up. Kot da bi štopal. Tako sem vedno kazal jaz, dokler nisem šel na potapljaški tečaj. Tam so mi povedali, da to pomeni “hočem gor”. Da se OK pokaže takole:

    Kot Vegeta. A-OK. In sem preklopil na Vegeto. In do sedaj mi je dobro služila.

    V Turčiji pa A-ok ni OK1.

    Making an ‘O’ with your thumb and forefinger (as if to say “OK!”) is rude because you are making the gesture for a hole – which has connotations refering to homosexuality in the Turkish psyche.
    Wikitravel

    Namesto tega priporočajo thumbs up.

    Ampak pozor, če potujete naprej v sosednji Iran:

    The thumbs up gesture is extremely rude in Iran, roughly equivalent to raising the middle finger in Western countries.
    Hitchhiking is rare in Iran, and the country has a good public transportation system. If you do hitchhike, do not use a thumbs up signal.
    Wikitravel

    V bistvu je tale thumbs up še v mnogih drugih kulturah bolj žaljiv od Vegete (ta je zares sporna samo v Turčiji in Venezueli, piše na Wikipediji, z zelo grafično razlago kaj pomeni).

    “Thumbs up” traditionally translates as the foulest of gesticular insults in some Middle Eastern countries — the most straightforward interpretation is ‘Up yours, pal!’ The sign has a similarly pejorative meaning in parts of West Africa, South America, Iran, Iraq, and Sardinia, according to Roger E. Axtell’s book Gestures: The Do’s and Taboos of Body Language Around the World.”
    Wikipedia

    Kaj pametnega lahko potegnem iz vsega tega? Da bom naslednjič definitivno prebral uporabne in zgoščene zapiske na Wikitravel. 🙂 In da ostajam pri A-ok.

    1. In to sem ugotovil zadnji dan, potem ko sem en teden veselo kazal A-ok na kar pogosta vprašanja, če mi še kaj manjka [↩]
     

    • dare 09:31 on 26 Sep. 2010 Permalink

      “…potem ko sem en teden veselo kazal A-ok…”

      si mislil, da si kazal.
      v resnici si kazal “that’s so gay, man”.

    • Nejc 12:56 on 2 Nov. 2010 Permalink

      Kot potapljač tudi jaz odobravanje pokažem s potapljaškim OK. Pa sem pogosto ugotovil, da večina ljudi tega ne razume in te potem čudno gledajo 🙂
      Sedaj se poskušam navaditi na Thumbs Up

  • Urban 01:42 on 4 Apr. 2010 Permalink |  

    Veliki trkalnik 

    Par zanimivosti o največjem znanstvenem eksperimentu v zgodovini, velikem hadronskem trkalniku (Large Hadron Collider, LHC), ki je 30. marca okrog 13h trknil 2 snopa protonov, ki sta imela energijo 3.5 TeV (tera elektronvoltov). Energija tega trka je bila tako 7 TeV, kar predstavlja točno polovico največje zmogljivosti LHC-ja.

    En elektronvolt (eV) je energija, ki jo pridobi en elektron, če preleti razliko potencialov en volt. Nekako tako, kot če spustiš jabolko s 3 metrov višine, in ko je dva metra nad tlemi, je preletelo razliko potencialov 1 meter (3m – 2m). Energija jabolka je enaka spremembi njegove potencialne energije, oz., po preprosti srednješolski formuli:

    ΔWp = m * g * Δh, kjer je
    m = masa,
    g = 9.8 m/s2,
    Δh pa višinska (to je, potencialna) razlika, ki jo preleti jabolko.

    Sprememba potencialne energije jabolka, ki tehta 200 g in preleti 1 m v gravitacijskem polju, bi tako bila:

    ΔWp = 0.2 kg * 9.8 m/s2 * 1 m
    ΔWp = 1.96 Joula (J)

    No, en elektron, ki bi na podoben način “padel” z enega na drug potencial v električnem polju in pri tem preletel potencialno razliko enega volta, pa bi na enak način pridobil samo 1.602×10−19 J energije (to je, 0.0000000000000000001602 J)1.

    Energije v trkalniku so tera elektronvolti, (tera je naslednja večja enota od giga). Tera = 1012 oz. milijon milijonov (1.000.000.000.000). Tako ima proton z energijo 3.5 TeV z drugimi besedami energijo 0.00000056 J, oz. kot pravijo v CERN-u, energijo letenja komarja. Ni slabo za en sam proton.

    Proton to energijo pridobi s kroženjem po tunelu z obsegom 27 km. Po celotnem obsegu sta položeni 2 cevi, ena za kroženje v smeri urinega kazalca, druga za obratno smer. V obeh ceveh je izjemno visok vakum, da se krožeči delci ne bi zaletavali v atome ali molekule plinov.

    Delce v cevi držijo sistemom superprevodnih magnetov, ki so ohlajeni na 1.9 K (temperatura, hladnejša kot prostor med galaksijami). Pri tej temperaturi postanejo prevodniki (navitje elektromagneta) superprevodni, kar omogoča uporabo velikih tokov praktično brez izgub (izgube pomenijo segrevanje). Skozi magnete teče tok 13.000 amperov.

    Curek protonov pospešijo do približno miljarde km/h (natančneje, do 99.9999991% svetlobne hitrosti, ki je najvišja mogoča hitrost), tako da obkrožijo celoten obroč pospeševalnika 11.000x v sekundi. Čeprav ima en proton le energijo letečega komarja, pa celoten curek nosi približno 360 MJ (milijonov Joulov), kar je enako energiji letalonosilke USS Ronald Reagan (103000 ton, polno naložena), ki pluje s 5 vozli (~10 km/h).

    Pri taki energiji oba v nasprotnih smereh krožeča curka trknejo vkup (tj, kot bi tresknili skupaj 2 letalonosilki), razbitine, ki letijo v vse smeti, pa zajamejo s štirimi detektorji (ALICE, ATLAS, CMS in LHCb), ki so videti kot čista znanstvena fantastika.

    ALICE je na spodnji sliki.

    Detektorji v dnevu obratovanja sproducirajo 27 TB podatkov, oz. približno 5900 DVD-jev. Tule se vidi grafe za trke 30. marca, ko je bil throughput prenosa podatkov iz CERN-a do CASTOR-ja (CERN Advanced STORage manager) približno 4 Gbit/s.

    Glavni cilj tega kolosalnega eksperimenta, vrednega 6,3 milijarde evrov, je iskanje Higgsovega bozona, ki je manjkajoči element v t.i. standardnem modelu fizike osnovnih delcev. Higgsov bozon, ki je zaenkrat še domneven, naj bi bil odgovoren za obstoj mase. Zaradi svoje velike teže je izjemno nestabilen in bo tudi v LHC-ju razpadel še preden ga bomo sploh lahko opazili. Opazili pa bomo črepinje (lažje delce), v katere bo razpadel. Če LHC ne najde Higgsovega bozona, bo to dokaz, da ta ne obstaja, in da so vse naše teorije za v smeti.

    Nuclear Physics The Large Hadron Collider (CERN LHC)

    Za odličen in poljuden pregled te tematike priporočam ogled BBC-jevega dokumentarca The Big Bang Machine. Če ga umaknejo, iščite po naslovu na Google video. Predava rockstar fizik Brian Cox, od katerega imam celo avtogram2 :).

    Vse slike so z Wikipedije.
    Update: dodal animacijo.
    Update: popravil nedoslednost.

    1. Čeprav je električno polje za naboje točno to, kar je gravitacija za maso, pa je potrebno upoštevati, da so naboji lahko tako pozitivni kot negativni, masa pa samo pozitivna. Zato bi v okolju, kjer ima električno polje enako smer kot gravitacija (to je, dol), pozitroni (+) padali kot žoge, elektroni (-) pa bi se dvigali kot helijevi baloni. [↩]
    2. Hvala Ivanka&co. 😉 [↩]
     

    • dare 10:36 on 5 Apr. 2010 Permalink

      krasno poljudno in jedrnato!

    • Urban 11:27 on 5 Apr. 2010 Permalink

      hvala 🙂

    • Dragan 12:12 on 5 Apr. 2010 Permalink

      Res lepo razloženo! Bom predlagal svojim študentom naj si preberejo tvoj prispevek.

    • Urban 12:14 on 5 Apr. 2010 Permalink

      za študente FE je pa najbrž mal preveč poljuden 🙂 bom mogu dat en disclaimer gor 🙂

    • Ivanka 17:00 on 5 Apr. 2010 Permalink

      Ti bi moral ‘odpreti’ en on-line izobraževalni center. Ljudje bi ti pošiljali kaj bi želeli vedeti, ti bi upoljudil stvar in lepo objavil.

  • Urban 16:59 on 20 Mar. 2010 Permalink |  

    Subliminal Tyler Durden 

    Been watching Fight Club and noticed a weird flash around 06:00. I thought it might have been a misplaced “Coming up next…” overlay, but when I scrubbed back, I was blown away. There it was, Tyler Durden, together with his shadow (which proves it was deliberate and carefully crafted), long before the character even appeared in the movie. (Later I found there are at least six such occurrences).

    It’s actually funny (and self-referencing), as one of Tyler’s jobs in the movie is to do the exact same thing:

    He flips the projectors, movie keeps going and the audience has no idea.
    Why would anyone want this shit job?
    Because it affords him interesting opportunities.
    Like splicing a frame of pornography into family films.

    (Source)

    This is an allegedly powerful concept of sending subtle messages to the audience, too fast for the eye, but not for the brain. The use of such subliminal imagery in the movies is supposed to evoke strong emotions of fear — some even claim unexplained fear.

    Although Wikipedia seems to question its effectiveness, there’s been quite some movies which use it, or at least claim they use it.

    Regarding the most famous example, the Exorcist (1973), there’s some controversy whether the imagery inserted there was truly subliminal (and whether you’ve actually seen it or not: it was apparently removed and reintroduced in different editions).

    But the most gruesome sequence I’ve ever (knowingly) seen (and deconstructed), was one of the final scenes of the Event Horizon. Strangely, I was unable to find any images from that movie, so I had to find a short clip and resort to mplayer1 to split it into frames. A selection of frames (viewer discretion is advised) is available here: Event Horizon subliminal pics. Some of the images are present for no more than a single frame, so there are many you’d have missed when watching the movie.

    Does it work? Who knows. Some say it does, or at least hint it does (e.g., Malcolm Gladwell’s Blink: The power of thinking without thinking), others claim it’s nonsense. Either way, I don’t want anyone to feed me images like these without my knowledge. There’s a fantastic analogy I’ve read somewhere: If someone came to your home, entered your living room and emptied the trash on your carpet, you’d probably kick his ass. But when someone empties mental trash in the living room of your mind, you don’t even register. Unless you pay really close attention.

    1. mplayer -vo jpeg videofile splits videofile into frames [↩]
     

    • alessandro boscolo 02:32 on 23 Mar. 2010 Permalink

      Hi,after years,when i gave look to those hellgiven photos , i’ve felt the same anguish,without having really seen theme,and just at the very beginning of the film i felt the same.It’s simply bad for me,to insert hiddenly,just to scare,seeding anguish,those images full of unuseless badness.Ok it?s a scifi horror,i didn’t know,but i received those…
      I’ve found in(lost in the space)some subliminals,i’ve found theme in a panoramic view of the station,they are images of classic stlized aliens figures,just to make you think they are not human facilities!.Bye and thanks for your non-distraction

    • liminal 01:58 on 19 Jun. 2015 Permalink

      if you want subliminal, check the movie Blade: in the very first scene of the very first movie, you’re shown people walking through a cold room with hanging meat, and while there’s nothing creepy in that scene, I felt really uncomfortable while watching it and suspected subliminal stuff. It took me some 30minutes until I managed to stop the video at the right 1/10 second to discover the subliminal image (which is the face of a guy with the throat cutted). You really cannot see it unless you stop the video at the right point, but your subconscious mind gets it. Clever.
      Of course, this was almost 20years ago and audio-visual techniques have made outstanding progresses since then (through computer effects), and the flash images are no longer the way to go for subliminal stuff, instead they can now interlace two images, one on top of the other but you can only see the one on top. Subliminal sound is also possible (sounds or words hidden between a sentence), I’ve seen a few movies where they used that process (the sound effects in a speach get strange and while you hear a sentence you will feel strange about what was said as your subconscious mind heard something else). Last but not least, visual effects and sound effects are often combined to suggest something completely different from what is heard and seen.

    • Urban 21:31 on 22 Jun. 2015 Permalink

      Hey, that’s a great find, I’ll check it out.

      I do find all of this fascinating–especially how easily we can be subtly influenced, because the subconscious mind is always watching/listening. I’ve seen this video of a Derren Brown “trick” some time ago, and couldn’t decide if it was for real or a hoax:
      https://www.youtube.com/watch?v=ZyQjr1YL0zg

      But I read about a controlled experiment, the “two cord puzzle”. There the subjects were asked to tie together two pieces of rope, hanging from the ceiling (the pieces were to far apart to be reached at the same time). No one thought of swinging the ropes to make them come closer together, until the experimenter “accidentally” brushed against a rope, and that provided the necessary clue. But every subject in the experiment was convinced that *they* thought of that brilliant idea on their own.

      Since then I believe that the video above is most likely real. And if that’s real, you can basically manipulate anyone just by feeding them subtle clues, and they’ll think it was their idea all along..

  • Urban 17:45 on 14 Dec. 2009 Permalink |  

    Slike in animacije 

    Eno moje dokaj staro predavanje o osnovah digitalnih slik (in animacij). Zadeva je še presenetljivo aktualna, glede na starost (skoraj 4 leta). Mogoče še bolj kot prej, ker so zdaj digitalci že od 30€ naprej in je res že vsak lahko sam svoj mojster obdelave slik. 🙂 Zadeva je nastala v okviru Laboratorija za telekomunikacije na FE. (Najbolje se vidi v celozaslonskem načinu.)

    Slike in animacije
    View more presentations from Urban Sedlar.

     

  • Urban 18:55 on 29 Nov. 2009 Permalink |  

    C64 nostalgija 

    Bral sem tale zanimiv članek o delu v CERN-u, kjer avtorja bolj zanima človeška plat zgodbe kot pa znanost. Ko fizika vpraša, kateri je bil njegov prvi računalnik, mu ta odvrne, da Commodore VIC-20 iz leta 1981, in začne razlagati o tedanjih vrhunskih igrah:

    “My favourite game was a little scrolling, spaceship-shooting game, but the playability was fantastic. I could play that game for years and not get bored. I have never been able to find a game better than that.”

    Še preden sem prebral do konca, sem že začel razmišjati o svojem prvem računalniku Commodore 64 in svoji najljubši igri, ki sem jo igral cele dneve (njenega imena pa se nisem dobro spomnil). Spomnil sem se samo, da sem bil fasciniran, ko sem prvič videl, česa je zmožen ta pisalni stroj, s katerim sem dobil tanko (slovensko) knjižico navodil za pisanje preprostih BASIC programov, kakršen je tale na spodnji sliki. 🙂

    c64_pozdrav

    Presenečen sem nad popularnostjo te teme na netu. Na Wikipediji imajo seznam c64 iger, kjer sem našel svoj naslov, potem pa na prvem sajtu na googlu stankal “disk image” (bolje rečeno tape image) in emulator. 🙂

    Igra (z imenom Exolon) je velika 32K (s 100 stopnjami in sintetitzirano glasbo vred). Danes (če uporabim “warp mode” emulatorja VICE C64) na mojem pcu teče 3800% (torej 38x) hitreje. Ne gre zanemariti, da je C64 star že 27 let (in da se številke za CPU ne ujemajo ravno z Moorovim zakonom, ker hitrost emulacije nima veze z dejansko hitrostjo procesorja; za RAM pa pride kar prav: podvojitev vsakih 19.5 mesecev, da v 26 letih pridemo s 64K na 4G).

    Exolon c64

    Zgoraj je screen capture igre. V emulatorju lahko celotno memorijo shraniš v 65K file (kar je manj od malo večje ikone) in nadaljuješ kasneje. Spodnja slika, npr., je v nekomprimirani obliki velika 65K.

    color copy

    Razvijalci, ki so kucali tole kodo pred 30 leti, si najbrž niso predstavljali, da bo enkrat tekla v emulatorjih na telefonih in v ročnih urah.. oz da bo sploh še kje tekla. Le kje bo tekla naša koda čez 30 let? 🙂

     

    • dare 00:39 on 30 Nov. 2009 Permalink

      zx spectrum FTW!

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