INTERNET socialites ought to prepare themselves: Facebook has changed again.

As of last week, the online home to 175 million people will look very different as the social networking site again revamps its home page, with a live news stream and friend "filters".

Facebook's move is an obvious reaction to the booming popularity of micro-blogging site Twitter and an attempt to keep its membership growing at five million users weekly.

But there is still doubt about whether users will be wooed by the facelift, or whether any of the competing websites will survive when all are yet to becpme profitable.

Facebook chief executive officer Mark Zuckerberg announced the latest changes last week, saying the alterations were not "something we've been working on for a long time", but a response to the increasing amount of information hosted on the site.

Mr Zuckerberg also warns this redesign will not be the final Facebook facelift.

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What's changed?

The main change to the new-look Facebook will be a feature called the Stream. Replacing the News Feed introduced in 2006, the Stream will show the updates your friends make in real-time, giving the site an immediacy similar to Twitter.

Mr Zuckerberg says the Stream's addition will accelerate the pace of updates, bringing members to Facebook to "consume and participate in the stream itself" rather than looking for just one type of content, such as status updates.

Facebook will also add Filters so users can categorise contacts: by family, friends, school mates and colleagues, for example.

Also, new profiles will be added for use by companies and public figures. Famous Facebookers including US President Barack Obama, cyclist Lance Armstrong, swimmer Michael Phelps, band U2 and TV news network CNN have already signed up to use these new profiles that will put their updates alongside those of your close friends.

"This means that you can find out that Oprah is reading a book backstage before a show, CNN posted a breaking story or U2 is working on a new song, just as you would see that your friend uploaded new photos from her trip to Europe," Mr Zuckerberg says.

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Twitter risks

Several of these additions to Facebook mimic behaviour already seen on Twitter. Even some of Facebook's new public figures, including Armstrong, are prolific Twitter users.

Twitter chief executive Evan Williams has gone out of his way to make some of these high-profile users welcome on Twitter, preventing web-savvy users from cyber-sitting on their famous names.

Celebrities including Demi Moore appear to appreciate this approach. The actress last week pledged her allegiance to the micro-blogging site online, saying: "Facebook is cool, but Twitter is the s- - -."

Deakin University communications and social media lecturer Ross Monaghan says this could be due to Twitter's design that allows users to participate in conversations, rather than sharing personal photo albums, applications, surveys and other information.

Mr Monaghan says the two warring sites are fundamentally different and Facebook's administrators need to be careful about changing their winning ways too much.

"Whatever Facebook does they need to be very, very careful that they don't alienate the existing users and they don't change what seems to be a winning formula so far," he says.

Mr Monaghan says rather than encouraging users to choose just one social networking avenue, enlightened internet users are likely to use two or three, maintaining different profiles for different communication.

Ultimately, though, both could disappear. Neither Facebook nor Twitter is profitable yet and while speculation mounts that Google could buy Twitter, and both continue to attract users, neither have a successful business model.

Mr Monaghan says far from crowning a winner, users should prepare for a day without the current social networking sites.

"The world wide web is coming up to its 16th birthday, which is an incredibly young age ... I think we're going to see incredible changes yet and it's far too early to say that anyone is a winner. We're not even halfway through round one," he says.

It is an open secret that Christopher Nolan is not a big fan of computer-generated visual effects. So when I read that there were over 650 visual effects shots employed in his Academy Award winning, biggest Hollywood blockbuster of 2008, The Dark Knight, I was genuinely surprised. I was curious to know what had made Nolan to give in - to compromise.

In Nolan’s defence, I came to understand that it was his wish to shoot the entire film using only practical effects like those employed to flip the Joker’s truck or the Gotham Central Hospital explosion sequences in the movie. However, the producers had to intervene when he came up to them and told them and he was planning to run the 5000-pound Batmobile into a garbage truck.

“I wanted to do that for real, but couldn't, and I had to accept that,” Nolan says. “But rather than doing it with computer graphics, we did it with large-scale miniatures, and I think it cuts very seamlessly into the film.”

Visual effects wizardry did come into play in creating the look of Two-Face's partly mangled visage, along with lots of completion and transition work. In a tense scene involving two ferries, “We built the dock and the front end of the ferries and extended them with CGI, but the loading platforms and the pier were real,” reveals production designer of the film, Nathan Crowley.

In another example of a composite sequence, “You have Batman on a building in Hong Kong. He jumps off that on green screen, and they comp in the background that we've shot in Hong Kong. We shoot some flying stuff on stage and they do some CG flying stuff and that's comped together. Then he's barrel vaulting through a window, and that's an interior built on a soundstage.”

For the first time in feature filmmaking, IMAX cameras were utilized. Christopher Nolan had wanted to shoot in the IMAX format for years, thus using this film as his opportunity to do so. Six major action-heavy sequences, along with various high-altitude shots, were filmed on the IMAX ratio.

To film the action Bat Pod sequences in IMAX, the team filmed from the back of a specially modified Mercedes SUV with an Ultimate Arm-Lev Head combination. So dramatic was the filming of the Armed car chase that a full IMAX camera, one of the four existing ones in the world at that time, was crushed and destroyed during filming.

“In essence, the Bat-Pod is to the world of motorcycles what the Tumbler is to the world of cars”, adds Nolan
Inarguably the most incredible thing that the City of Chicago allowed the production to do was unprecedented: flipping a 40-foot tractor-trailer, end over end, right in the heart of the city's banking district on La Salle Street. This amazing shot was almost entirely done in camera.

According to the film's production notes, when Chris Corbould saw the truck flip described in the script, he admits, "I tried to make compromises with Chris—like maybe the whole truck doesn't go over or maybe we could use a smaller truck—but he wasn't having any of it."

Nolan responds, “Finally I turned to him one day and said, ‘Chris, it really ought to be an 18-wheeler. And I know you can find a way to do this because that's just who you are and that's what you do.’ The first order of business was to make sure the stunt was even possible.

"After about six weeks of calculations, we were ready to do an actual test," recalls Corbould.

“We went out to an open space, got the truck up to speed and pressed the button, and it just sailed over. I had to go to Chris Nolan and tell him it worked perfectly.” Nevertheless, the filmmakers were aware that there was a vast difference between flipping a truck in the middle of nowhere and doing it in the middle of a city street. Before they could carry out the stunt, city engineers were called in to make sure that the tons of force necessary to send the truck end over end would not damage the infrastructure of La Salle Street, including the various utility lines that run beneath it.

Once safe parameters were determined, the production was given the green light. When the night of the stunt came, the truck flip went like clockwork, earning applause from the assembled cast and crew. “It was an impressive thing to watch this truck fly over and land precisely where Chris said it was going to land,” Nolan remarks. “At the top of its arc, it looked almost like a skyscraper standing there, and then it just continued going over very gracefully. I have never seen anything like it.”

Neither have we, Mr. Nolan.

Most of us must have heard of this mysterious "cloud computing" thing in recent years. Its the latest buzzword. Microsoft is into cloud; Google wants some clouds; Amazon is also cloudy (duh! Its a rainforest). Everyone wants a piece of the cloud.

So what the hell is the cloud?

Lets try youtubing it. The first result for "Cloud computing" in youtube is a 9 minute long video. Run through it quickly and you willl see that the big guys dont seem to have a common definition of the cloud. There is a bit of the internet, some complex sounding terms and a lot of vagueness :

Lets try this one:

Interesting video.. very informative - gives a lot of information about how the internet works, but one still doesnt understand why the cloud is so different, what the cloud exactly is, and how it is constructed.

Now, let us see what the CEO of Oracle has to say:

THAT seems to make sense! There is nothing new about the cloud! And as you check out more videos and as the picture of the cloud gets cloudier, you will probably start agreeing with Larry Ellison...

Now, the Wikipedia entry for cloud computing starts off with a geeky 

"Cloud computing is Internet (cloud) based development and use of computer technology (computing), whereby dynamically scalable and often virtualised resources are provided as a service over the Internet"
???????????

What the hell does that mean? Relax. As we read further, we see "The cloud is a metaphor for the Internet...". BINGO! Thats all there is to it. The cloud is basically the internet as we use it today. Just that. The internet. A hyped up, cool version of the internet.

Let me answer 2 questions that are probably clouding your mind now:

Q1) If the cloud is just the internet, what were those 2 long videos in the beginning talking about?

If you notice carefully, they were simply describing the internet as it is today. Interconnected.. you dont care where your data is stored.. can be accessed using multiple devices.. blahblah.. It is simply describing the internet you are connected to right now. The difference between the Internet and the Cloud is the same difference between the Ford Model T and a BMW. And cloud computing is basically using this "cloud" to do computing.

Q2) So then, why cant we just call it the internet? 

It's not cool enough!

Every now and then the IT industry (like any other industry) comes up with buzzwords like "Web 2.0" and "Cloud Computing" to reinforce the "cool" factor and also to make sure the distance between the IT guys and everyone else increases. (A simple way to maintain price level you see..)

So, the next time I tell you that my software has built-in "Cloud" functionality, remember that I probably just mean that it can connect to the internet!

Sudoku originated in Japan and means “the digits must remain single”. It is a type of logical puzzle, which makes use of numerical symbols simply for convenience. A Sudoku is a 9 by 9 grid, made up of nine non-overlapping 3 by 3 blocks. Some of the cells will be given a value from 1 to 9. The objective of the game is to fill up all the other blank cells with number 1 to 9 so that in each row, column or box, none of the digits is repeated. There are various variants of a Sudoku, a simple one called the Shi Doku, being a 4 by 4 grid. It retains all the features of a Sudoku, except that there are only 4 values – 1 to 4 – that can be given to each box.

This was a part of the project that I had done in my Junior College days for the Singapore Youth Science Festival, where we won a gold medal for our research on Sudoku and Shi Doku.

Let me define the basic terms first. A solution is a puzzle in which all the cells are filled. Basic solutions are those that cannot be formed by any transformations on other basic solutions. Transformations on all the basic solutions are non-overlapping and they form all the available Shi Doku. Those formed from different basic solutions are essentially different. A proper puzzle is one that has one and only one solution.

There are certain well known proofs about the Shi Doku, like that the total number of solutions is 288 and the number of basic Shi Doku solutions is 2. Let us dwell into the proof of the minimum number of inputs for a proper puzzle.

Proof:

Shi Doku puzzles with less than three inputs us improper. It is because two or more values are not used. The re-labelling between these unused values will result in more than one solution.

Consider the first input. By swapping of rows, columns and vertical/ horizontal double, we can always move this input to cell (1, 1). The other two inputs must be of different values; otherwise, two of the values are not used and re-labelling between them produces two different solutions. By re-labelling again we can assume the second and third inputs to be 2 and 3 respectively.

Should the second clue be placed in either the first row or column, there would be two rows and columns left blank after placing the third clue. This will certainly lead to an improper Shi Doku. Therefore, we can ascertain that the second clue is in the remaining 3x3 square.

Consider this 3x3 square, if the second clue lies beneath the leading diagonal, which passes through cell (1, 1), it can always be transposed to he upper part above the diagonal. For example:                                             
                                                                                   
The number 2 in the cell (4, 2) and below the diagonal, can be transposed to cell (2,4), above the diagonal.

Now, second clue can only be in one of the following cells (2, 2), (2, 3), (2, 4), (3, 3), (3, 4) and (4, 4). If the second clue is in cell (3, 4) or (2, 4) it can be transformed into cell (3, 3) or (2, 3) respectively by swapping column 3 and 4. If the second clue is in cell (4, 4), it can be transformed into cell (3, 4) by swapping row 3 and 4, and then to cell (3, 3) by swapping columns 3 and 4. Hence, the second clue can only be in cells (2, 2), (3, 3), (2, 3).

Case 1: the second clue is in cell (2, 2).
The third clue can not be in the first and second columns (or rows).If it is so, there will be two blank columns (or rows), which results in an improper puzzle.

Hence the third clue can only be in the remaining 2x2 square .However, any position of the third clue within this square can be transformed back to the cell (3,3) by a combination of swapping row and column. Thus, we have the general puzzle for this case as
                                                                       

This puzzle will have at least 2 solutions as shown below
.                                          
Thus, this puzzle is not proper. Therefore, all the puzzles in this case (reduced by transformations) are improper

Case 2: The second clue is in the cell (2, 3).
The first and second rows, the first and third columns can not contain the third clue. If it is so, there will be two blank columns (or rows), which results in an improper puzzle. Hence the third clue can only be in these cells: (3, 2), (3, 4), (4, 2) and (4, 4). However, by row swapping, the number in the cell (4, 2) or (4, 4) can be transformed to cell (3, 2) or (3,4) respectively. Therefore, we can only reduce the possible locations of the third clue to either cell (3, 2) or cell (3, 4).

A. If the third clue is in the cell (3,2)
The puzzle is as follow

We are able to give two solutions as followed:
                                                                  
              
B. If the third clue is in cell (3,4)
       The puzzle is as follow
                                                       
We are able to give two solutions as followed:
                                  
Thus, this puzzle is not proper. Therefore, all the puzzles in this case (reduced by transformations) are improper

Case 3: the clue lies in cell (3, 3)
The third clue can not be in the first and third columns (or rows).If it is so, there will be two blank columns (or rows), which results in an improper puzzle. Hence the third clue can only be in cells (2,2),(2,4),(4,2) and (4,4).However with the third clue in the cell (2,2), we come back to the situation in the first case. In addition, by transposition, the number in the cell (4, 2) can always be transformed to cell (2, 4).

Therefore, we can only reduce the possible locations of the third clue to either cell (2,4) or cell(4,4). A. The third clue is in cell (2,4)
The puzzle is as follow
                                                           
We can give two solutions as follow
                               

B. The third clue is in cell (4, 4).
       The puzzle is as follow
                                                           
We can give two solutions below
                     
Thus, this puzzle is not proper. Therefore, all the puzzles in this case (reduced by transformations) are improper

Therefore all three-input Shi Doku puzzles are improper

There exist four-input Shi Doku that are proper. Below is one such example with its unique solution.
                   

Therefore, the minimum number of inputs for a proper Shi Doku is 4

Expansion to Sudoku

Certain approaches used in this analysis of the Shi Doku might be useful for the investigation of the 9 by 9 Sudoku, though the details are probably much more complicated.