Saturday, September 20, 2008
Zeller's rule is used to calculate the day on which any date falls for any year. With this technique you will have the calendar for any given year available to you.
The rule is as follows
f = k + [(13*m - 1)/5] + d + [d/4] + [c/4] - 2*c
where,
k = day of month
m = month number, taking Mar=1, ..., Dec=10, Jan=11, Feb=12
d = last two digits of year, using the previous year for Jan and Feb
c = first two digits of year
Rules:
1.In Zeller's rule the year begins in March and ends in February. Hence, the month number from March is 1, April is 2, May is 3 and so on up to January, which is 11, and February is 12.
2.January and February are counted as the 11th and 12th months of the previous year. Hence, if you are calculating the day of any date on January 2026, the notation will be (month=11 and year= 2025) instead of (month=1 and year=2026).
3.While calculating, we drop off every number after the decimal point.
4.Once we have found the answer we divide it by 7 and take the remainder. Remainder 0 corresponds to Sunday; Remainder 1 corresponds to Monday ; Remainder 2 corresponds to Tuesday and so on....
Example:
Find the day on 26th June 1983
f = k + [(13*m - 1)/5] + d + [d/4] + [c/4] - 2*c
Here k=26, m=4, d=83, c =19
f= 26+(13*4-1/5)+83+83/4+19/4-2*19
= 105
105 divided by 7 leaves a remainder 0. Hence the day is a Sunday!
Derivation of the formula:
Here we're defining
k = day of month
m = month number, taking Mar=1, ..., Dec=10, Jan=11, Feb=12
d = last two digits of year, using the previous year for Jan and Feb
c = first two digits of year
The formula is then
f = k + [(13*m - 1)/5] + d + [d/4] + [c/4] - 2*c
and we use the remainder after dividing f by 7 to find the day of the
week.
Where does this come from? Let's first note the reason for the odd
handling of months: we want leap day not to affect the formula, so we
move it to the end of the 'year', and act as if the year began on
March 1.
Now note that in defining f, all we care about is the remainder after
dividing, so it will be enough to make sure that f increases by 1
whenever the day of the week advances by one day; we don't care about
the actual value of f.
Now let's build the formula piece by piece.
How does the year affect the day? Well, since 365 = 7*52+1, each
normal year advances the day by 1, so our formula can start with the
year number:
f = d
Whenever the year advances by 1, so does the day of the week.
But we have to adjust this to account for leap years. Every four years
we have an extra day, so we'll want to add 1 to f. This is done by
adding [d/4], since this increases by 1 only when d becomes a multiple
of 4, which is a leap year. So now we have
f = d + [d/4]
Now how do centuries affect the day? A century contains 100 years, 24
of which normally are leap years (since century days, like 1900, are
NOT leap years). So each century the day advances by 124 days, which
is 7*18-2, and therefore the day of the week goes BACK 2 days. So we
have
f = d + [d/4] - 2*c
But every fourth century year IS a leap year (as 2000 was), so we
have to adjust just as we did for leap years:
f = d + [d/4] - 2*c + [c/4]
Now we come to the months, and this is the cute part. Consider, for
each month, how many days it has BEYOND 28, and then add that up to
see the effect the months have on the day of the week:
1 2 3 4 5 6 7 8 9 10 11 12
Month Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb
Days 31 30 31 30 31 31 30 31 30 31 31 (28)
Excess 3 2 3 2 3 3 2 3 2 3 3 0
Accum 0 3 5 8 10 13 16 18 21 23 26 29
\_________________/\__________________/\_______
The number of accumulated days is counted at the start of the month,
so if we divide it by 7, the remainder shows how many weekdays the
start of the month is from the starting day for the 'year'.
Notice the pattern in the excess: 3,2,3,2,3 repeats every five months,
and the accumulation reaches 13 in that time. So every 5 months, we
want to add 13 days. That suggests that we want to add a term like
[13m/5]. That doesn't quite give us what we want:
1 2 3 4 5 6 7 8 9 10 11 12
Month Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb
Days 31 30 31 30 31 31 30 31 30 31 31 (28)
Excess 3 2 3 2 3 3 2 3 2 3 3 0
Accum 0 3 5 8 10 13 16 18 21 23 26 29
13m 13 26 39 52 65 78 ...
[13m/5] 2 5 7 10 13 15 ...
If we subtract 2 from this, it isn't quite right; we have to shift it
a bit. So after playing with it a bit, we find
13m-1 12 25 38 51 64 77 ...
[(13m-1)/5] 2 5 7 10 12 15 ...
[(13m-1)/5]-2 0 3 5 8 10 13 ...
That's just what we want. So we'll use
f = d + [d/4] - 2*c + [c/4] + [(13m-1)/5] - 2
Finally, we have to add the day, since each day obviously adds one to
the day of the week; and adjust to get the right day of the week for,
say, Mar 1, 2000, since nothing we've done so far actually determined
WHICH day we start the whole pattern on. It turns out that we can just
remove the -2, and we get
f = d + [d/4] - 2*c + [c/4] + [(13m-1)/5] + k
And there's the formula!
Friday, September 5, 2008
A butterfly with transparent wings is rare and beautiful. As delicate as finely blown glass, the presence of this rare tropical gem is used by rain forest ecologists as an indication of high habitat quality and its demise alerts them of ecological change. Rivaling the refined beauty of a stained glass window, the translucent wings of the Glasswing butterfly shimmer in the sunlight like polished panes of turquoise, orange, green, and red.
All things beautiful do not have to be full of color to be noticed: in life that which is unnoticed has the most power.
The above picture is not an ms paint or photoshop work. It's a real picture. And just observe the pattern formed by the birds. Amazing! It justifies the title, one in a million shot!
Wednesday, September 3, 2008
Google has launched a new browser called google chrome. The interface of the browser is pretty simple. But it's damn fast.
Descrpition by google:
Google Chrome is a browser that combines a minimal design with sophisticated technology to make the web faster, safer, and easier.
Download link: http://www.google.com/chrome
Screenshot of google chrome
An article about google chrome from the google blog:
At Google, we have a saying: “launch early and iterate.” While this approach is usually limited to our engineers, it apparently applies to our mailroom as well! As you may have read in the blogosphere, we hit "send" a bit early on a comic book introducing our new open source browser, Google Chrome. As we believe in access to information for everyone, we've now made the comic publicly available -- you can find it here. We will be launching the beta version of Google Chrome tomorrow in more than 100 countries.
So why are we launching Google Chrome? Because we believe we can add value for users and, at the same time, help drive innovation on the web.
All of us at Google spend much of our time working inside a browser. We search, chat, email and collaborate in a browser. And in our spare time, we shop, bank, read news and keep in touch with friends -- all using a browser. Because we spend so much time online, we began seriously thinking about what kind of browser could exist if we started from scratch and built on the best elements out there. We realized that the web had evolved from mainly simple text pages to rich, interactive applications and that we needed to completely rethink the browser. What we really needed was not just a browser, but also a modern platform for web pages and applications, and that's what we set out to build.
On the surface, we designed a browser window that is streamlined and simple. To most people, it isn't the browser that matters. It's only a tool to run the important stuff -- the pages, sites and applications that make up the web. Like the classic Google homepage, Google Chrome is clean and fast. It gets out of your way and gets you where you want to go.
Under the hood, we were able to build the foundation of a browser that runs today's complex web applications much better. By keeping each tab in an isolated "sandbox", we were able to prevent one tab from crashing another and provide improved protection from rogue sites. We improved speed and responsiveness across the board. We also built a more powerful JavaScript engine, V8, to power the next generation of web applications that aren't even possible in today's browsers.
This is just the beginning -- Google Chrome is far from done. We're releasing this beta for Windows to start the broader discussion and hear from you as quickly as possible. We're hard at work building versions for Mac and Linux too, and will continue to make it even faster and more robust.
We owe a great debt to many open source projects, and we're committed to continuing on their path. We've used components from Apple's WebKit and Mozilla's Firefox, among others -- and in that spirit, we are making all of our code open source as well. We hope to collaborate with the entire community to help drive the web forward.
The web gets better with more options and innovation. Google Chrome is another option, and we hope it contributes to making the web even better.
So check in again tomorrow to try Google Chrome for yourself. We'll post an update here as soon as it's ready.
Posted by Sundar Pichai, VP Product Management, and Linus Upson, Engineering Director
Article source: http://googleblog.blogspot.com/2008/09/fresh-take-on-browser.html
Atlast google has entered the browser war, instead of supporting Mozilla it's good that google has started it's own browser.
I have already started using this browser. I feel the difference instantly (it gives high speed browsing). You too can try!
Yesterday while reading newspaper (The Hindu) one particular news in the last page caught my attention. It was titled "Elephants know their sums"
Below is the article from hindu:
Tokyo: Asian elephants can do mathematics, and have proved their skill at addition in an experiment with their favourite food, a Japanese researcher said on monday.
One elephant was 87 percent correct and the other was 69 percent right in months of addition exercises involving single digits, says Naoko Irie of the University of Tokyo.
In one test, researchers dropped three apples into one bucket and five into another bucket and then added two apples to each. Five times out of six, Ashya, a 30 - year old female elephant at Tokyo's Ueno Zoo, chose the bucket with seven apples rather than five although see or feel the inside of the containers.
The other elephant, 38 - year - old Mito from Kyoto, was also right five times in a test involving oranges.
Ms. irie; a doctal candidate in cognition and behavioural science, said she was surprised at the elephants' mathematical skills. "I couldn't believe it at first," she said. "They could instantly compare numbers like six and five."
Each animal was tested using their favourite food. Elephants have roughly the same life span as humans.
Many animals are known to be able to choose te bigger of two numbers. Their perfomances, however, usually decline if the numbers are big or the gap between the two numbers is small.
I believe all animals know maths. Only human beings are proud of it because they have conventional methods in maths.
Tuesday, September 2, 2008
The following picture describes how software engineers jump from one job to another.
This is a really cool picture.
Monday, September 1, 2008
In literature, a red herring is a narrative element intended to distract the reader from a more important event in the plot, usually a twist ending.
The term "red herring" originates from the tradition whereby young hunting dogs in Britain were trained to follow a scent with the use of a "red" (salted and smoked) herring (see kipper). This pungent fish would be dragged across a trail until the puppy learned to follow the scent. Later, when the dog was being trained to follow the faint odor of a fox or a badger, the trainer would drag a red herring (which has a much stronger odor) across the animal's trail at right angles. The dog would eventually learn to follow the original scent rather than the stronger scent.
In literature, the most commonplace use of a "red herring" is in mystery fiction. One particular character is described or emphasized in a way that seems to throw suspicion upon that character as the person who committed the crime: later, it develops that someone else is the guilty party.
This is used in cryptography as well!
In cryptography, a red herring is a second hidden message that is intended to be discovered more easily so that the real message remains hidden to anyone who might intercept the transmission and break the red herring code. Only the intended receiver would know the key to unlocking the real message.
It consists of a crtogram section which is very tough. I was able to solve only one puzzle there and I have posted it here!
The following cryptogram is a quote from a popular movie. It's a very short quote, so it makes the cryptogram a bit more difficult to decypher. It is possible to crack the code as long as you work at it.
81 12 81 415. 50626 39 41 527.
I didn't even work it out. I was able to figure it out.
Being an ardent lover of Starwars how could I forget the quote by Jedi Master Yoda!
Description:
Help the priests and devils to cross the river. Be careful though, they don't like each other. If the number of Devils is greater than the number of priests (on either side of the bank), then the Priests would be killed by the Devils.
Hope you enjoyed this puzzle game!
Try a similar kind of game which I have posted in my blog long back.
THE IQ GAME....TIME TO TEST YOUR IQ!!!!
