GATE CSE 2011
Q31.
Consider a finite sequence of random values X=[x_{1},x_{2},...,x_{n}]. Let \mu _{x} be the mean and \sigma _{x} be the standard deviation of X .Let another finite sequence Y of equal length be derived from this as y_{i}=a*x_{i}+b, where a and b are positive constants. Let Let \mu _{y} be the mean and \sigma _{y} be the standard deviation of this sequence. Which one of the following statements is INCORRECT?Q32.
Which one of the following options is CORRECT given three positive integers x, y and z, and a predicate P(x)=\neg (x=1)\wedge \forall y(\exists z(x=y*z))\Rightarrow (y=x)\vee (y=1)Q33.
Let P be a regular language and Q be a context free language such that Q \subseteq P. (For example, let P be the language represented by the regular expression p*q* and Q be \{p^{n}q^{n}|n\in N\} Then which of the following is ALWAYS regular?Q34.
Consider a relational table r with sufficient number of records, having attributes A_{1}, A_{2},..., A_{n} and let 1\leq p\leq n . Two queries Q1 and Q2 are given below. Q1:\pi _{A_{1}....A_{n}}(\sigma _{A_{p}=c}(r)) where c is a constant Q2:\pi _{A1....A_{n}}(\sigma _{c_{1}\leq A_{p}\leq c_{2}}(r)) where c_{1} and c_{2} are constants The database can be configured to do ordered indexing on A_{p} or hashing on A_{p}. Which of the following statements is TRUE?Q35.
Consider a relational table with a single record for each registered student with the following attributes. 1. Registration_Number: Unique registration number for each registered student 2. UID: Unique Identity number, unique at the national level for each citizen 3. BankAccount_Number: Unique account number at the bank. A student can have multiple accounts or joint accounts. This attributes stores the primary account number 4. Name: Name of the Student 5. Hostel_Room: Room number of the hostel Which of the following options is INCORRECT?Q36.
An application loads 100 libraries at startup. Loading each library requires exactly one disk access. The seek time of the disk to a random location is given as 10ms. Rotational speed of disk is 6000rpm. If all 100 libraries are loaded from random locations on the disk, how long does it take to load all libraries? (The time to transfer data from the disk block once the head has been positioned at the start of the block may be neglected)Q37.
Consider a database table T containing two columns X and Y each of type integer. After the creation of the table, one record (X=1,Y=1) is inserted in the table. Let MX and MY denote the respective maximum values of X and Y among all records in the table at any point in time. Using MX and MY, new records are inserted in the table 128 times with X and Y values being MX+1, 2*MY+1 respectively. It may be noted that each time after the insertion, values of MX and MY change. What will be the output of the following SQL query after the steps mentioned above are carried out? SELECT Y FROM T WHERE X=7;Q38.
Database table by name Loan_Records is given below. What is the output of the following SQL query? SELECT count(*) FROM( (SELECT Borrower. Bank_Manager FROM Loan_Records) AS S NATURAL JOIN (SELECT Bank_Manager, Loan_Amount FROM Loan_Records) AS T);Q39.
Let the time taken to switch between user and kernel modes of execution be t1 while the time taken to switch between two processes be t2. Which of the following is TRUE?Q40.
A thread is usually defined as a 'light weight process' because an operating system (OS) maintains smaller data structures for a thread than for a process. In relation to this, which of the followings is TRUE?