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China has demonstrated the most growth in scientific research of any country in the past three decades and is on pace to overtake the United States as the world’s scientific leader by 2020, according to a recent Thomson Reuters study. The study found that China has experienced a 64-fold increase in peer-reviewed scientific papers since 1981. “China is out on its own, far ahead of the pack,” says the Royal Society of London’s James Wilsdon. Chinese researchers also have become more eager to work with international colleagues, with almost nine percent of Chinese-based papers having at least one U.S.-based co-author. Three main factors are driving China’s boom of scientific research, Wilsdon says. The government has made an enormous financial investment, new scientific breakthroughs are organized to flow from basic science to commercial applications, and Chinese researchers based in the United States and Europe are being recruited back to China.

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The U.S. National Institute of Standards and Technology (NIST) has completed round one of its open competition to create a new Secure Hash Algorithm (SHA). The cryptographic community narrowed the first round’s 64 submissions down to 14 semifinalists. Fifty-one of the 64 algorithms submitted in 2008 met the competition’s minimum criteria, and it took the judges a year to examine the entries for flaws and weaknesses. “We were pleased by the amount and quality of the cryptanalysis we received on the first round candidates, and more than a little amazed by the ingenuity of some of the attacks,” says NIST’s Bill Burr. Five finalists are expected to be named from the 14 remaining entries by the end of this year, and a new standard, which will be named SHA-3, should be ready in 2012. SHA-3 will replace the SHA-1 and SHA-2 algorithms currently being used by NIST. This is the third open cryptographic competition conducted by NIST, the first coming in the 1970s, and the second in the 1990s.

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Happy new year!

I hope it would be a year full of achievements, health and peace for all of us.

Best wishes,
Be happy ever!

I wonder why nowhere on the net is found that mention the requirements of the complement operation on automata or precisely define this operation.

In fact complement operation is only defined on deterministic automata. Applying it to NFAs will result to strange things. For example, consider the following automata:

You might think that its complement is the following automaton:

But it isn’t. The automaton above accepts both h and the empty string.

Another important thing about DFAs before applying the complement operation is to add a halt or sink state.

Thus for the following automaton:

The complement is as follows:

You should note that the complement of an automaton that accepts h doesn’t mean an automaton that accepts everything other than h. If fact the complement of an automaton with language L and alphabet ∑ is an automaton that accepts ∑* – L. So complementing an automaton that accepts h with alphabet {h} is an automaton that accepts h* except the string containing a single h. Therefore the complement automaton accepts h* – h = {λ,hh,hhh,hhhh,…}.

I hope it was useful ;)

In the time remaining to the ACM-ICPC regional contest, about 80 days, we should work harder for preparing. Some of my friends are feeling discouraged :( and have stopped their activities for the contest. Unfortunately, the limited time of projects of the Algorithms course has discouraged them rather than improving their confidence, hope and interest, the key ingredients needed for the contest.

I’m thinking of making a new team but there are few people around like to take part in. Anyway in the time that I’ve almost finished the excellent Professor Cormen’s Introduction to Algorithm, I’m going to focus more on the practical aspect of theories. The following month is really important for us, and I hope other friends do their job too.

Recently, I was re-installing my linux operating system because it couldn’t detect a newly installed hardware. It was really easier than installing a windows os on my system. Even reconfiguring whole of the system is easy. Installing a windows os needs tens of applications to be installed after the installations, but you might need few packages to be installed after your linux installations.

If you’ve not tried the Linux yet, do it now. It’s a great experience!

Thanks to the great planning of our department has had for the ACM team, today we just encountered the closed door of the department computer lab.

Two of the team members come from 300 km far from Qazvin. A few days ago we just could get the entrance permission with much difficulty and they just permitted us for today. Today we just got a closed door. Really thanks!!

Neither there was any one to open the door of the atelier, nor they’ve got the key to us for using it (why didn’t they? I really don’t know!! Probably they didn’t trust us :@ ).

I really do not know that how much they’ve got the competitions seriously, however, I think they’ve got it more like a game than a real competition.

Forget it