Tuesday, August 15, 2006

Websites that changed the world

Amazon
used to be a large river in South America - but that was before the
world wide web. This month the web is 15 years old and in that short
time it has revolutionised the way we live, from shopping to booking
flights, writing blogs to listening to music. Here, the Observer's Net
specialist charts the web's remarkable early life and we tell the story
of the 15 most influential websites to date. Tell us what you think of
our choices here








John Naughton
Sunday August 13, 2006
The Observer








Johannes
Gutenberg took the idea of printing by moveable type and turned it into
a publishing system. In doing so he changed the world. But he did not
live to see the extent of the revolution he had brought about. If you'd
told him in 1468 - the year he died - that the Bible he had published
in 1455 would undermine the authority of the Catholic church, power the
Renaissance and the Reformation, enable the Enlightenment and the rise
of modern science, create new social classes and even change our
concept of childhood, he would have looked at you blankly.

But
there lives among us today a man who has done something similar, and
survived to see the fruits of his work. He is Tim Berners-Lee, and he
conceived a system for turning the internet into a publishing medium.
Just over 15 years ago - on 6 August 1991, to be precise - he released
the code for his invention on to the internet. He called it the World
Wide Web, and had the inspired idea that it should be free so that
anyone could use it.

And just about everyone did, with the result
that the web grew exponentially. Today nobody really knows how big it
is. At a recent conference, Yahoo's head of research and development
put the size of the public web at 40 billion pages, but the size of the
'deep' web, the area where web pages are assembled on the fly and
served up in response to clicked-upon links, is estimated to be between
400 and 750 times greater than the part that is indexed by search
engines. Since you started reading this piece, thousands of pages have
been added.

By any standards, the web represents a colossal
change in our information environment. And the strange thing is that it
has come about in just 15 years. Actually, most of it has happened in
less than that, because the web only went mainstream in 1993, when the
first graphical browsers - the computer programs we use to access the
web - were released. So these are early days. We can no more envisage
the long-term implications of what has happened than dear old Gutenberg
could.

The strangest thing is how casually we have come to take
it for granted. We buy books from Amazon, airline tickets from Easyjet
and Ryanair, tickets for theatres and cinemas online, as if doing so
were the most natural thing in the world. We check the opening times at
the Louvre in Paris or the Museum of Modern Art in New York (or browse
their collections) online. We check definitions (and spellings) in
online dictionaries, look up stuff in Wikipedia, search for apartments
to rent on Craigslist or a host of local lookalikes such as Daft.ie in
Ireland. You can buy and sell just about anything (excluding body
parts) on eBay. Children seeking pictures for school projects search
for them on Google Images (and download them without undue concern for
intellectual property rights). Holiday snaps escape from their
shoeboxes and are published to the world on Flickr. Home movies
likewise on YouTube. And of course anyone with doubts about a
prospective blind date can do an exploratory check on Google before
committing to an evening out with a total stranger.

All this we
now take for granted. To get a handle on the scale of what has
happened, think back to what the world was like 15 years ago. Amazon
was a large river in South America. Ryanair was an Irish airline that
flew to places nobody had ever heard of. eBay was a typo. Yahoo was a
term from Gulliver's Travels. A googol was a very large number (one
followed by a hundred zeroes). Classified ads were densely printed
matter in newspapers. 'Encyclopedia' was a synonym for Encyclopedia
Britannica. And if you wanted to read what your MP had said in the
Commons yesterday you had to queue at the Stationery Office in London
to buy Hansard. Oh, and there were quaint little shops in high streets
called 'travel agents'.

To celebrate the 15th anniversary of the
web we've assembled a list of sites that have become the virtual
wallpaper of our lives. What the corresponding list will be like in 15
years' time is anyone's guess. As the man said, if you want to know the
future, go buy a crystal ball. In the meantime, read on and wonder.

· John Naughton's history of the internet, A Brief History of the Future, is published by Phoenix at £7.99

1. eBay.com

Founded: Pierre Omidyar, 1995, US

Users: 168m

What is it? Auction and shopping site

You
cannot buy fireworks, guns, franking machines, animals or lock-picking
devices on eBay, the internet's premier auction site, but almost
everything else is OK: sideburns, houses, used underwear and of course
Pez dispensers.

Pez is where it is said to have all begun for
eBay's ponytailed founder Pierre Omidyar when he responded to his
fiancee's worries that she would no longer be able to expand her toy
collection when they moved to Silicon Valley. Omidyar developed a car
boot sale anyone could use wherever they were, and without the need for
getting dressed. The name sprang from Echo Bay Technology Group,
Omidyar's consultancy company, and the first sale was a broken laser
pointer.

Things have moved on a little since then. We spend more
time on eBay than any other internet site. There are more than 10
million users in the UK. And eBay is far from just a second-hand stall.
New items are sold by global companies; many people have abandoned
their jobs to eBay full time, and normally sane people fret about
'negative feedback' and being outbid by 'snipers'. eBay owns PayPal and
Skype, making dealing almost effortless.
Simon Garfield

2. wikipedia.com

Founded: Jimmy Wales, 2001, US

Users: 912,000 visits per day

What is it? Online encyclopaedia

As
a young boy growing up in Hunstville, Alabama, Jimmy Wales attended a
one-room school, sharing his classes with only three other children.
Here he spent 'many hours poring over encyclopaedias', and faced the
familiar frustrations: their scope was conservative; they were hard to
navigate and often out of date.

In January 2001 he created a
solution. Wikipedia was a free online encyclopaedia and differed from
its predecessors in one fundamental regard: it was open to everyone to
read, and also to edit. If you had something to add - from a pedantic
correction to an entire entry on your specialist subject - the Wiki
template made this easy. The software enables entries to be updated
within minutes of new developments. There is nothing you cannot find -
how best to make glass, the use of the nappy in space exploration - and
if something isn't there, you may wish to take matters into your own
hands.

Like any fast-moving venture - the site attracts
2,000-plus page requests a second - it has not been slow to attract
criticism. Occasionally a libellous article will lie undetected for
months, as happened with an entry linking one of Robert Kennedy's aides
with his assassination. But Wales says his creation is abused only
rarely, and swiftly corrected by other users. 'Those who use Wikipedia
a lot appreciate its true value and have learnt to trust it,' he says.
'Sometimes a prankster will substitute a picture of Hitler for George
Bush, and within an hour someone would have changed it back.'
SG

3. napster.com

Founded: Shawn Fanning, 1999, US

Users: 500,000 paying subscribers

What is it? File sharing site

Shawn
Fanning created Napster in 1999 while studying at Boston's Northeastern
University, as a means of sharing music files with his fellow students.
Of course, it was entirely illegal (home taping kills music, remember)
and was quickly attacked by a mainstream music industry already
struggling to make profits on its money-guzzling artists. Its
popularity reached a peak in 2000 with over 70 million registered users
before Fanning's company was forced to pay millions of dollars in
backdated royalties: a move which bankrupted the original, free-to-use
Napster the following year. By then, however, the premature leaking and
sharing of hotly anticipated albums by some of the major labels' most
bankable artists had proved to be a stimulant, not a thief, of sales
once the CD version was released. The new Napster - effectively a
renamed version of a pay-to-download MP3 site owned by the original
Napster company's buyers, the German giant Bertelsmann- has never
recaptured its original cool, precisely because it is now legitimate.
What it did in its brief period of illegal notoriety was popularise the
notion that making music freely available on the internet - through
MySpace, one-off downloads or artist-sanctioned 'leaks' - does artists
no harm at all; indeed, it's helped to launch the careers of many.
Lynsey Hanley

4. youtube.com

Founded: Chad Hurley, Steve Chen and Jawed Karim, 2005, US

Users: 100m clips watched a day

What is it? Video sharing site

When
Chad Hurley and Steve Chen began working out of a garage in San Mateo
in late 2004 to figure out an easy way to upload and share funny videos
they'd taken at a dinner party, they had no idea just how huge an
impact their creation would make. The former PayPal employees launched
the user-friendly site in February 2005 and it has since become one of
the most popular sites on the net, with YouTube claiming that 100
million clips are watched every day. Through the grassroots power of
the internet and good word-of-mouth, the site quickly went from a place
where people shared homemade video clips to users posting long-lost TV
and film gems such as bloopers from Seventies game shows to ancient
music videos. It has also taken off as a place for amateur film-makers
to show off their talents - take David Lehre, a teenager whose MySpace:
The Movie became such a popular clip he's already fielded job offers
from major movie studios.

Not all television studios immediately
embraced the idea of their archived copyrighted footage being shared.
'We're not here to steal,' insists Chen. 'When [US television network]
NBC asked us to take something down, we did.' In fact, NBC only last
week announced plans to work alongside YouTube, airing exclusive clips
and trailers and eventually hoping to post episodes of The Office and
Saturday Night Live on it. The company has had several offers to be
bought out, but the pair swear they will not sell out. They continue to
work out of their San Mateo loft, overseeing 27 employees and
developing ways to make the site easier to use while whirling lucrative
deals with studios.
Gillian Telling

5. blogger.com

Founded: Evan Williams, 1999, US

Users: 18.5m unique visitors

What is it? Weblog publishing system

There
weren't too many computers lying around in the cornfields of Nebraska
in the 1970s when Evan Williams was growing up. But he was drawn to
them when he found them. He was also drawn west, to California in the
1990s. Williams founded Pyra Labs with two friends. At first it made
project-management software for companies. It was not glamorous. Then
it made Blogger and changed the world.

'The funny thing was I
actually hesitated before working on Blogger because I didn't see the
commercial applications,' says Williams. 'We had started a company and
we needed to make money. We didn't see how this little hobbyist
activity was going to make anyone money.'

The little hobbyist
activity was blogging, the art of keeping a weblog - of diarising,
theorising, satirising, fictionalising your life and observations
online. It had already taken off among the tech fraternity in the
Nineties, but it required building and maintaining your own website;
the luddites were excluded. Williams created a tool that made
self-publishing online as user-friendly as word-processing. It is hard
to exaggerate the importance of this innovation. It didn't just create
a new form of creative expression, it turned the media upside down.

Content
was once made by companies for passive consumption by people. After
Blogger, people were the content. They wrote about and read about their
friends, their opinions, their cats. (There was a lot about cats in the
early blogs.) None had a huge audience but collectively they were
massive. 'Now you see TV networks saying: "We've gotta get on the web
because that's where the audience is,"' says Williams.

There is
no accurate count of the number of blogs in existence now. There are
millions. One is created every minute. The revolution might have been
possible without Blogger but it would have taken everyone a lot longer.

'Something
like it would have existed anyway,' says Williams. 'And lots of things
like it do exist. It was a combination of helping push an idea as well
as just being in the right place at the right time when the idea was
right.'
Rafael Behr

6. friendsreunited.com

Founded: Steve and Julie Pankhurst, 1999, UK

Users: 15m

What is it? School reunion site

In
July 2000, as the dreams of the internet boom crumbled around them, a
husband-and-wife team were busy launching a rough and ready web
phenomenon. Friends Reunited, which was sold to ITV for £120m last
December, was Julie Pankhurst's brainchild. While pregnant, she became
obsessed with finding out what her old friends had been up to since
they left school. Her husband Steve, a computer programmer, had been
brainstorming with his business partner Jason Porter for an original
internet-based idea, and Julie suggested a website to cater for her
newfound obsession. It took her some time to convince them. 'In the
end,' says Steve, 'I designed Friends Reunited just to shut her up.'

The
site took off slowly, getting half a dozen hits per day, but everything
changed at the start of 2001 when its lone server collapsed. 'The Steve
Wright show on Radio 2 had made us their website of the day. Tens of
thousands of people had tried to access the site at the same time.'
Within a month membership rose from 3,000 to 19,000; the couple were
working 18-hour days. Friends Reunited quickly became a household name
and membership soared into the millions.
Killian Fox

7. drudgereport.com

Founded: Matt Drudge, 1994, US

Users: 8-10m page views per day

What is it? News site

What
began as a gossipy email newsletter has, since its first post in 1994,
developed into one of the most powerful media outlets in American
politics. Today the Drudge Report has evolved into a website,
drudgereport.com, and its threadbare, no-frills design belies the scale
of its influence. It received an estimated 3.5 billion hits in the last
12 months; visitors regard it as the first port of call for breaking
news.

Fedora-wearing founder Matt Drudge monitors TV and the
internet for rumours and stories which he posts as headlines on his
site. For the most part these are direct links to traditional news
sites, though occasionally Drudge writes the stories himself. In 1998
he was the first to break news of the Monica Lewinsky scandal.

Named
this year as one of Time magazine's 100 most influential people, the
38-year-old regards himself as a maverick newsman working free from the
demands of editors and advertisers. Others, particularly critics from
the left, view his reportage as biased towards conservatives, careless,
malicious and frequently prone to error.

A report in 1997,
alleging that White House assistant Sidney Blumenthal physically abused
his wife, generated a $30m lawsuit against Drudge, which was dropped in
2001. In June 2004, Drudge apologised for a February 'world exclusive'
claiming that John Kerry had had an affair with an intern.

Drudge
has been labelled a 'threat to democracy' and an 'idiot with a modem'
as well as 'the kind of bold, entrepreneurial, free-wheeling,
information-oriented outsider we need more of in this country' (by
Camille Paglia); his importance in the US media is undisputed.
KF

8. myspace.com

Founded: Tom Anderson and Chris DeWolfe, 2003, US

Users: 100m

What is it? Social networking site

When
business-school alumnus Chris DeWolfe set up the social networking site
MySpace with his partner, ex-band member and film studies graduate Tom
Anderson, three years ago, there was little indication that the
one-stop online friend-making shop would soon boast 100 million members
and more page visits in Britain than the BBC. The pair envisaged a site
that would bring together all the qualities of existing online
communities such as Friendster, Tribe.net and LiveJournal, with added
features including classified adverts and events planning.

They
got the formula just right: the MySpace-opolis is growing by 240,000 a
day, making it the fourth most-visited website in the world. DeWolfe
believes that the key to the site's success is its founders' rapport
with the people who use it. 'We looked at it from the point of view of
how people live their lives,' he says.

One of those features is
the ability to upload and listen to music, which has attracted 2.2
million new bands and artists to the site, some of whom - most famously
Lily Allen and Arctic Monkeys - can attribute their chart success to
having spread the word through MySpace.

MySpace's parent company,
Intermix, was bought by Rupert Murdoch's NewsCorp last year for $580m,
causing consternation among some of the music world's more politicised
acts, but no large-scale boycott. The site is simply too valuable and
effective - and ubiquitous - to ignore.
LH

9. amazon.com

Founded: Jeff Bezos, 1994, US

Users: More than 35m customers in over 250 countries

What is it? Online retailer, primarily of books, CDs and DVDs

The
earth's biggest bookstore was originally called Cadabra, but Jeff Bezos
thought again after his lawyer misheard it as 'cadaver'. He chose
Amazon as something large and unstoppable and so, with current annual
revenues of $8bn, it has proved. It was just a trickle to begin with
though: the first office was in a Seattle suburb with desks made out of
old doors. But it quickly became the headline act of the dotcom miracle
and Bezos was Time magazine's man of the year in 1999. Amazon's
continued dominance rests on price-slashing that would make Wal-Mart
wince, and a reputation for reliability. Though selling books (and now
almost everything else) on a vast scale, it has tried never to forget
the value of intimacy.
Tim Adams

10. slashdot.org

Founded: Rob Malda, 1997, US

Users: 5.5m per month

What is it? Technology news website and internet forum

'I'm
just a geek that likes to poke around with hardware,' says Rob Malda.
His site, Slashdot.org, hosts news and discussion for techies and is
one of the most visited websites in the world. Time magazine included
him in its top 100 innovators, stating: 'Malda has taken the idea of
what news can be, hacked it open and rebuilt it for the internet age.'

Most
of the site is written by users; posts include a short synopsis
paragraph, a link to the original story and a lengthy discussion
sometimes running to 10,000 comments a day. Slashdot pioneered this
user-driven content, and influenced sites including Google News,
Guardian Unlimited and Wikipedia. In 2002 the site leaked the ruling of
a court case involving Microsoft before the verdict had even been
delivered to Microsoft or the US government. There is also the Slashdot
effect, where a site is swamped by heavy traffic from a Slashdot link
and its server collapses.

In 1997, 21-year-old Malda started what
we would now call a blog, hosted on his user account at university. As
the site picked up users he divided his time between college, paid work
and the site. 'It was a blur. There were many nights when I did not
sleep.' Two years later Andover bought Slashdot for $5m, shared between
Malda, co-founder Jeff 'Hemos' Bates and other partners. They also
shared $7m in stock between them. In 2000 VA Linux (now VA Software)
bought Andover for $900m. Slashdot now has 10 employees dedicated to
maintaining the site, most of them based in California. Malda has
remained in Michigan, where he grew up and went to college. He is
director of Slashdot. He proposed to his wife Kathleen on the site in
2002.
Katie Toms

11. salon.com

Founded: David Talbot, 1995, US

Users: Between 2.5 and 3.5m unique visitors per month

What is it? Online
magazine and media company Salon grew out of a strike. When the San
Francisco Examiner was shut for a couple of weeks in 1994 a few of its
journalists taught themselves HTML and had a go at doing a newspaper
with new technology. They found the experience liberating, and David
Talbot, the Examiner's arts editor, subsequently gave up his job and
launched the kind of online paper he had always wanted to work for.
Salon was originally a forum for discussing books, but the editors
quickly realised it had to be more journalistic than that. They aimed
at creating a 'smart tabloid', not afraid to be mischievous while
maintaining a rigour with news. Talbot believes that online journalism
came of age with the death of Princess Diana and the Lewinsky scandal.
It proved with those events that it could be nimbler and more gossipy,
it could update itself continually and, crucially, let readers join in.
Salon's Table Talk forum established a new relationship between a news
outfit and its audience, letting readers write themselves into the
story.

Salon was not afraid of muck-raking. When Talbot decided
to run a story about Henry Hyde, who was to sit in judgment of Bill
Clinton after the Starr report, he was roundly criticised not just by
the entrenched Washington media but also by some on his own staff. The
story concerned Hyde's extramarital affair of 30 years before, and the
more august sections of the American media, not to mention the
right-wing impeachers of the President, thought this was beyond the
pale. Talbot recalls how Salon 'got bomb threats, I received death
threats... [but] I think if as a new organisation that comes into the
world, a new media operation, you don't take risks with stories that no
one else does, then what's the point?'

For all its journalistic
success, Salon has always struggled financially. A couple of times the
site has nearly gone under; on one occasion Talbot was forced to fire
his wife who ran a women's page. A subscription system saved it, along
with the growth in online advertising. These days Talbot sees Salon's
competitors as the big news organisations, the New York Times and so
on, who have strong online presence. Having shown a few of them how
it's done, Salon now faces a daily battle to stay ahead of the game.
TA

12. craigslist.org

Founded: Craig Newmark, 1995, US

Users: 4bn page views per month

What is it? A centralised network of online urban communities, featuring free classified advertisements and forums

Craigslist
is one of the most deceptively simple websites on the internet. It is
also one of the most powerful. It is - pretty much - simply a free
noticeboard. But its astonishing popularity has given it immense power.
Want to rent an apartment? Sell a car? Find a job? Meet someone to
spend the night with? Craiglist will provide the answers. For free. It
has revolutionised urban living in America. It has also undercut one of
the main reasons for newspapers: classified advertising. As nearly all
Craigslist's content is free, it rarely censors ads and its readers
number in the millions, it is far more useful to post an advert on the
site than in your local newspaper. Thus a huge decline in newspaper ads
and revenue, triggering cost-cutting which will see reporters tossed on
to the scrap heap... and the end of a free press and democracy as we
know it (if the critics are to be believed).

The website was
founded by Craig Newmark, an ubergeek with a hippyish mentality. It
started as a simple email that he would send around listing various
events going on in San Francisco. From such humble beginnings
Craigslist has grown into a multi-million-dollar business. Yet Newmark
refuses to sell his company or charge for every ad.

Why should you care? Craigslist is all over the world - and coming to your home town soon.
Paul Harris

13. google.com

Founded: Larry Page and Sergey Brin, 1998, US

Users: A billion search requests per day

What is it? Search engine and media corporation

Its
name is listed as a verb in the Oxford English Dictionary. It commands
the largest internet search engine in the world. It is the
fastest-growing company in history and its founders are worth almost
$13bn each.

The search method devised by Larry Page and Sergey
Brin was instrumental to Goggle's success. Rather than ranking results
according to how many times the search term appeared on a page, their
system measured the frequency with which a website was referenced by
other sites. Another key factor was the site's stripped-down design,
which made it speedier and more accessible than its competitors.

From
such plain foundations a gigantic empire has sprung and is branching
out into email (with Gmail), news (Google News), price comparison
(Froogle), cartography (Google Maps), literature (with the much
contested Google Book Search), free telephony (Google Talk), and, most
strikingly, Google Earth, an incredibly detailed virtual globe. Google
styles itself as a laidback, hippyish organisation but its founding
motto, 'Don't Be Evil', is already being tested: the compromise it
reached with China over censorship has proved particularly contentious.
KF

14. yahoo.com

Founded: David Filo and JerryYang, 1994, US

Users: 400m

What is it? Internet portal and media corporation

It
receives an average of 3.4bn page hits a day, making it the single most
visited website on the internet, but in recent years Yahoo! has been
eclipsed by Google. Both companies were launched on a very small scale
by Stanford University graduates and, very soon the portal that Jerry
Yang and David Filo had started as a hobby was en route to becoming the
most popular search engine on the web. On the back of its early
success, Yahoo! (an acronym for 'Yet Another Hierarchical Officious
Oracle') branched out into email, instant messaging, news, gaming,
online shopping and an array of other services.

It also started
buying up other companies such as Geocities, eGroups and the web radio
company Broadcast.com. Yahoo! survived the internet collapse at the
start of the decade and brought former Warner Bros chief exec Terry
Semel on board in 2001 to navigate the difficult waters of the
post-boom period. Semel began to address the challenge of making money
out of the internet without relying on advertising revenue alone.
Google notwithstanding, Yahoo! is still very much a contender.
KF

15. easyjet.com

Founded: Stelios

Haji-Ioannou, 1995, UK

Users: 30m passengers last year

What is it?: Budget airline

It's
easy to forget what it was like back in the old days, when we didn't
just pay a tenner, pitch up at Luton and pop over to Rome for the
weekend. We mini-breaked in Bournemouth. Travelling to Scotland was an
all-day affair. Airlines issued quaint old-fashioned things such as
meals. And tickets. And seats.

And then along came Stelios.
That's Stelios as in Haji-Ioannou, although he now, alongside Delia and
Jamie and Sven, belongs in that rare category - the surnameless
celebrity. He's also that other elusive British beast - the celebrity
entrepreneur. In 1995, after borrowing £30m from his dad, a shipping
magnate, he leased two second-hand Boeings and began selling flights to
Scotland for £29 each way.

EasyJet was the first low-cost British
airline and, presciently, the first to start taking bookings over the
internet, although, as Stelios admits, he wasn't won over straight away.

'We
started off as something very obscure like 1145678.com. And I said:
"This is never going to fill the planes. It's just for nerds." Then
some time in 1997 we bought the domain easyjet.com for about £1,000 and
put up a proper website. At that time we had the telephone number in
big letters on the side of the plane. And we put a different telephone
number on the website. Week after week I watched how quickly the
numbers were growing and that gave me the confidence in April 1997 to
launch a booking site.'

It was, he says, the neatest and simplest
way: 'you outsource the work to the customer'. And it turned him into
an internet evangelical. The first company he set up after easyJet was
easyInternetcafe and all 15 companies in the easyGroup have some sort
of web component.
Carole Cadwalladr

Thursday, July 20, 2006

How R We Live? by Singer

Calvanist, Puritan, American: work is a divine calling, and weatlth a mark of grace

Tuesday, July 18, 2006

freeman.pdf [IJCV221]Learning Low-Level Vision

the idea of patch is important here, training is only carried on "scenes rendered the similar patch".

so PCA is used as representation of data. so how about msg passing between patches? (We need to chose a representation for the image and scene variables. The images and scenes are arrays of vector valued pixels, indicating, for example, color image intensities or surface height and reflectance information. We divide these into patches. For both compression and generalization, we use principle components analysis (PCA) to find a set of lower dimensional basis functions for the patches of image and scene pixels. We measure distances in this representation using a Euclidean norm, unless otherwise stated.)

Important PDFs

Skin related:
freeman.pdf Learning Low-Level Vision - WTY Freeman, ECY Pasztor, OTY Carmichael - IJCV.
TR2004-040.pdf "Constructing Free-Energy
Approximations and Generalized Belief Propagation Algorithms
"
Yedidia, J.S.; Freeman, W.T.; Weiss, Y., , IEEE Transactions on Information Theory,2005

[study guide] Spatial skin

Theory: Genearalized Belief Propagation TR2004-040.pdf
Algo: Check the IJCV02, low level vision freeman.pdf
Problem: The training set only has 2 classes, while the theory need 4 (skin, nonskin, skin-hightlight, non-skin-highlight[optional?], Maybe I should focus on the problem, then study the existing literature with direction)
Solution: Under help of human knowledge?

VLC and SRTP

VLC 0.8.5 compiled, but
[1] cann't demux TS over UDP now.
[2] when play mpeg (V-span), got error of "cannot open shared object file: No such file or directory"

possible solutions:
[a] check the library/plugin and recompile, summarize [1]&[2],it seems dvbpsi has problem
[b] debug the source code

how to add SRTP to VLC?
[1] modify the source code of VLC, adding SRTP feature (using libSRTP) to RTP part of VLC.
[2] leaving the payload alone(H264,TS), as long as I can show the result!
[3] after that, using key stream to encrypt SRTP, and then communicate key stream to terminal, terminal use this key stream to decrypt SRTP.
[3] encrypt the key stream follow the spec.......
....