PoiNtEr->: February 2011

                             Difference between a dream and an aim. A dream requires soundless sleep, whereas an aim requires sleepless efforts.

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Thursday, February 24, 2011

March toward Success(GATE-2012)

"Hard work is like a Staircase & Luck is like a Lift.

Lift may fail but Staircase is sure to take you to the TOP. ”


“Nothing is impossible for a willing heart”


“It is not your aptitude, but your attitude, that determines your altitude”


“God gives every bird its food but he doesn’t throw it into nest”


”A goal properly set is halfway reached”


“Hard work is the best investment a human being can make”


“Nobody plans to fail, they just fail to plan”


“Minds are like parachutes; they only function when open”


“Be not afraid of learning slowly; be afraid only of standing still”


“Fear of failure is ten thousand times more terrifying than failure itself”


“If you can dream it, you can do it”


“Action without delay is the secret of success”


“You are the architect of your life”


Last but not least...

“Quotations are short sentences, but drawn from long experiences”


Saturday, February 19, 2011

P2R -1(gate-2012)

Points 2 Remember(P2R)-1

1:UDP does not include congestion Control mechanism.

2:TCP include a congestion control mechanism.

3:HTTP is said to be a Stateless Protocol.

4:Ftp is not a stateless protocol

5:In ftp port 21(tcp control connection) remain open throughout the duration of the user session but

new tcp data connection(through port 20) is created for each file transferred with session(non-persistent)

6:HTTP is a PULL protocol

7:SMTP is a PUSH protocol

8:Minimum bandwith of Manchester and Manchester differential is 2times of NRZ.

9:Complexity of LL(1) grammer parsing n token is O(n).

10:NYQUIST theorm: C=2Wlog(M)

Friday, February 18, 2011

poset (GATE-2012)

What is a poset?

The term “poset” is short for “partially ordered set”, that is, a set whose elements

are ordered but not all pairs of elements are required to be comparable in the order.

Just as an order in the usual sense may be strict (as <) or non-strict (as ≤), there

are two versions of the definition of a partial order:

A strict partial order is a binary relation S on a set X satisfying the conditions

(R−) for no x ∈ X does (x, x) ∈ S hold;

(A−) if (x, y) ∈ S, then (y, x) ∈ S;

(T) if (x, y) ∈ S and (y, z) ∈ S, then (x, z) ∈ S.

A non-strict partial order is a binary relation R on a set X satisfying the conditions

(R+) for all x ∈ X we have (x, x) ∈ R;

(A) if (x, y) ∈ R and (y, x) ∈ R then x = y;

(T) if (x, y) ∈ R and (y, z) ∈ R then (x, z) ∈ R.

Condition (A−) appears stronger than (A), but in fact (R−) and (A) imply

(A−). So we can (as is usually done) replace (A−) by (A) in the definition of a

strict partial order. Conditions (R−), (R+), (A), (T) are called irreflexivity, reflex-

ivity, antisymmetry and transitivity respectively.

Properties of posets:

An element x of a poset (X, R) is called maximal if there is no element y ∈ X

satisfying x <R y. Dually, x is minimal if no element satisfies y <R x.

In a general poset there may be no maximal element, or there may be more

than one. But in a finite poset there is always at least one maximal element, which

can be found as follows: choose any element x; if it is not maximal, replace it

by an element y satisfying x <R y; repeat until a maximal element is found. The

process must terminate, since by the irreflexive and transitive laws the chain can

never revisit any element. Dually, a finite poset must contain minimal elements.

An element x is an upper bound for a subset Y of X if y ≤R x for all y ∈ Y .

Lower bounds are defined similarly. We say that x is a least upper bound or l.u.b.

of Y if it is an upper bound and satisfies x ≤R x for any upper bound x . The

concept of a greatest lower bound or g.l.b. is defined similarly.

A chain in a poset (X, R) is a subset C of X which is totally ordered by the

restriction of R (that is, a totally ordered subset of X). An antichain is a set A of

pairwise incomparable elements.

Infinite posets (such as Z), as we remarked, need not contain maximal ele-

ments. Zorn’s Lemma gives a sufficient condition for maximal elements to exist:

Let (X, R) be a poset in which every chain has an upper bound. Then

X contains a maximal element.

As well known, there is no “proof” of Zorn’s Lemma, since it is equivalent

to the Axiom of Choice (and so there are models of set theory in which it is

true, and models in which it is false). Our proof of the existence of maximal

elements in finite posets indicates why this should be so: the construction requires

(in general infinitely many) choices of upper bounds for the elements previously

chosen (which form a chain by construction).

The height of a poset is the largest cardinality of a chain, and its width is the

largest cardinality of an antichain. We denote the height and width of (X, R) by

h(X) and w(X) respectively (suppressing as usual the relation R in the notation).

In a finite poset (X, R), a chain C and an antichain A have at most one element

in common. Hence the least number of antichains whose union is X is not less

than the size h(X) of the largest chain in X. In fact there is a partition of X into

h(X) antichains. To see this, let A1 be the set of maximal elements; by definition

this is an antichain, and it meets every maximal chain. Then let A2 be the set of

maximal elements in X \ A1 , and iterate this procedure to find the other antichains.

Wednesday, February 16, 2011

Conditional Probability (GATE-2012)

Suppose we assign a distribution function to a sample space and then learn that

an event E has occurred.How should we change the probabilities of the remaining

events? We shall call the new probability for an event F the conditional probability

of F given E and denote it by P (F |E).

lets try to understand the concept of conditional probability by taking few examples.

In the Life Table , one finds that in a population

of 100,000 females, 89.835% can expect to live to age 60, while 57.062% can expect

to live to age 80. Given that a woman is 60, what is the probability that she lives

to age 80?

This is an example of a conditional probability. In this case, the original sample

space can be thought of as a set of 100,000 females. The events E and F are the

subsets of the sample space consisting of all women who live at least 60 years, and

at least 80 years, respectively. We consider E to be the new sample space, and note

that F is a subset of E. Thus, the size of E is 89,835, and the size of F is 57,062.

So, the probability in question equals 57,062/89,835 = .6352. Thus, a woman who

is 60 has a 63.52% chance of living to age 80.

Consider our voting example : three candidates A,

B, and C are running for office. We decided that A and B have an equal chance of

winning and C is only 1/2 as likely to win as A. Let A be the event “A wins,” B

that “B wins,” and C that “C wins.” Hence, we assigned probabilities P (A) = 2/5,

P (B) = 2/5, and P (C) = 1/5.

Suppose that before the election is held, A drops out of the race.

it would be natural to assign new probabilities to the events B and C which

are proportional to the original probabilities. Thus, we would have P (B| A) = 2/3,

and P (C| A) = 1/3. It is important to note that any time we assign probabilities

to real-life events, the resulting distribution is only useful if we take into account

all relevant information. In this example, we may have knowledge that most voters

who favor A will vote for C if A is no longer in the race. This will clearly make the

probability that C wins greater than the value of 1/3 that was assigned above.

We have two urns, I and II. Urn I contains 2 black balls and 3 white

balls. Urn II contains 1 black ball and 1 white ball. An urn is drawn at random

and a ball is chosen at random from it. We can represent the sample space of this

experiment as the paths through a tree as shown in above Figure. The probabilities

assigned to the paths are also shown.

Let B be the event “a black ball is drawn,” and I the event “urn I is chosen.”

Then the branch weight 2/5, which is shown on one branch in the figure, can now

be interpreted as the conditional probability P (B|I).

Suppose we wish to calculate P (I|B). Using the formula, we obtain

P (I|B)=P (I ∩ B)/P(B)

=P (I ∩ B)/P (B ∩ I) + P (B ∩ II)

=(1/5)/(1/5 + 1/4)


Tuesday, February 15, 2011


yeah i think i had underperformed in gate -2011.I had expected a lot but didn't able to make that much this year.(only 22 marks out of 100)
well all my hard work gone in vain??
no its not ..well i had one more chance in my last year.Its going to be hard as i have to make a balance between
my college study and my gate preparation
Gate-2011 was not that easy as i expected ...No question were easy but it
just People(gate aspirants) working so hard that make it difficult for other.
Well i known one thing that i wont let any other to take my seat this year(gate-2012).I will surely make it to top 100 ....
& its not my over confidence ,,,
well what i realized after giving exam that i have few weak points and i have t only work on that..
list of weak points::
1:silly mistake while converting units like i did in one question where i had taken 10m sec=10^-3.
2:Joins(outer,natural etc)
4:Vector Distance and link state algo concept
5:Software Engg.
6:Graph theory
7:scope of function and Recursive Function
8:and last but not the least SPEED
Well i am also thinking to post each topic i study daily....so please join me for discussion

Tuesday, February 8, 2011

Wowwww !!! Did you know this?

1 MOPED is the short term for 'Motorized Pedaling'.

2. POP MUSIC is 'Popular Music' shortened.

3. BUS is the short term for 'Omnibus' that means everybody.

4. FORTNIGHT comes from 'Fourteen Nights' (Two Weeks).

5. DRAWING ROOM was actually a 'withdrawing room' where people withdrew after Dinner. Later the prefix 'with' was dropped..

6. NEWS refers to information from Four directions N, E, W and S..

7. AG-MARK, which some products bear, stems from 'Agricultural Marketing'.

8. JOURNAL is a diary that tells about 'Journey for a day' during each Day's business.

9. QUEUE comes from 'Queen's Quest'. Long back a long row of people as waiting to see the Queen. Someone made the comment Queen's Quest..

10. TIPS come from 'To Insure Prompt Service'. In olden days to get Prompt service from servants in an inn, travelers used to drop coins in a Box on which was written 'To Insure Prompt Service'. This gave rise to the custom of Tips.

11. JEEP is a vehicle with unique Gear system. It was invented during World War II (1939-1945). It was named 'General Purpose Vehicle (GP)'.GP was changed into JEEP later.

12. Coca-Cola was originally green.

13. The most common name in the world is Mohammed..

14. The name of all the continents end with the same letter that they start with.

15. The strongest muscle in the body is the tongue.

16. TYPEWRITER is the longest word that can be made using the letters only on one row ! of the keyboard.

17. Women blink nearly twice as much as men!!

18. You can't kill yourself by holding your breath.

19. It is impossible to lick your elbow.

20.. People say "Bless you" when you sneeze because when you sneeze, your heart stops for a millisecond.

21. It is physically impossible for pigs to look up into the sky.

22. The "sixth sick sheik's sixth sheep's sick" is said to be the toughest tongue twister in the English language.

23. Each king in a deck of playing cards represents a great king from history.

>> Spades - King David

>> Clubs - Alexander the Great,

>> Hearts - Charlemagne

>> Diamonds - Julius Caesar.

24. Horse Statue in a Parkâ€Â¦

>> If a statue of a person in the park on a horse has both front legs in the air, the person died in battle.

>> If the horse has one front leg in the air, the person died as a result of wounds received in battle

>> If the horse has all four legs on the ground, the person died of natural causes.

25. What do bullet proof vests, fire escapes, windshield wipers and laser printers all have in common? Ans. - All invented by women.

26. A crocodile cannot stick its tongue out.

27. A snail can sleep for three years.

28. All polar bears are left handed.

29. Butterflies taste with their feet.

30. Elephants are the only animals that can't jump.

31. In the last 4000 years, no new animals have been domesticated.

32. On average, people fear spiders more than they do death.

33. Shakespeare invented the word 'assassination' and 'bump'.

34. Stewardesses is the longest word typed with only the left hand.

35. The ant always falls over on its right side when intoxicated.

36. The electric chair was invented by a dentist.

37. The human heart creates enough pressure when it pumps out to the body to squirt blood 30 feet.

38. Rats multiply so quickly that in 18 months, two rats could have over million descendants.

39. Wearing headphones for just an hour will increase the bacteria in your ear by 700 times.

40. If you sneeze too hard, you can fracture a rib. If you try to suppress a sneeze, you can rupture a blood vessel in your head or neck and die.

41. The cigarette lighter was invented before the matchbox.

42. Most lipstick contains fish scales

Saturday, February 5, 2011

The Years of Engineering

Class of People doing Engineering:

F.E. Fond of Engineering

S.E. Sick Of Engineering

T.E. Tired of Engineering

B.E. balls to Engineering

Engineers Anthem:

Hum Honge All Clear,Honge AllC lear,

Honge All Clear Ek Din, OH-HO,

Mann me hai vishwas, pura hai vishwas,

hum ho! ge all clear ek din

Top two Engineering Rumors:

'Did you hear the results are being put up today at 5:30pm'

'Did you hear the exams are postponed by two weeks, its been put up at notice board'

The most dreaded acronym for Engineers:

ATKT ( After Trying Keep Trying)

The most important criteria while selecting an engineering college:

Girl to Boy ratio ( if more than 0.025% then that college is engineers dream come true)

Engineers at work:

Assignments solved by one and then carrying out mass transfer operations throughout the class

The most important machine for Engineers:

Xerox Machine (Without which assignment completion wouldn't be possible)

The most important table in an Engineer's House:

The glass table ( to carry out GT operations, during Night Duty.)

The only queue an Engineer is familiar with:

Submission Queue

An Engineer's favourite watch:

Bird Watch !

Common Engineering Dialogues after a paper:

'What is this yaar, more than 70% of the paper was out of the syllabus'

'This was the worst paper set in the entire engineering history'