Question Banks

DBMSB.E./B.Tech. DEGREE EXAMINATION, APRIL/MAY 2010. Fourth Semester Computer Science and Engineering CS2251 - DATABASE MANAGEMENT SYSTEMS (Common to Information Technology) (Regulation 2008) Time: Three hours Answer ALL Questions. PART A- (10 X 2= 20 marks) Maximum:100 marks

1. Explain the basic structure of a relational database with an example. 2. What are the functions of a DBA? 3. Give the usage of the rename operation with an example. 4. What do you mean by weak entity set? 5. What is normalization? 6. Write a note on functional dependencies. 7. What do you mean by a transaction? 8. Define the term ACID properties. 9. Describe flash memory. 10. List out the physical storage media.

PART B- (5 X 16 = 80 Marks)

11. (a) (i) Discuss the various disadvantages in the file system and explain how it can be overcome by the database system. (6 Marks) (ii) What are the different Data models present? Explain in detail. (10 Marks) (Or) (b) (i) Explain the Database system structure with a neat diagram. (10 Marks) (ii) Construct an ER diagram for an employee payroll system. (6 Marks)

12. (a) (i) Explain the use trigger with your own example. (8 Marks) (ii) Discuss the terms Distributed databases and client/ server databases. (8 Marks) (Or) (b) (i) What is a view? How can it be created? Explain with an example. (7 Marks) (ii) Discuss in detail the operators SELECT, PROJECT, UNION with suitable examples. (9 Marks)

13. (a) Explain 1NF, 2NF and 3NF with an example. (16 Marks) (Or) (b) Explain the Boyce- Codd normal form with an example. Also state how it differs from that of 3NF. (16 Marks)

14. (a) (i) How can you implement atomicity in transactions? Explain. (8 Marks) (ii) Describe the concept of serializability with suitable example. (8 Marks) (Or) (b) How concurrency is performed? Explain the protocol that is used to maintain the concurrency concept. (16 Marks)

15. (a) What is RAID? Explain it in detail. (16 Marks) (Or) (b) Mention the purpose of indexing. How this can be done by B+ tree? Explain. (16 Marks)

PQTB.E./B.Tech. DEGREE EXAMINATION, APRIL/MAY 2010. Fourth Semester Computer Science and Engineering MA2262- PROBABILITY AND QUEUEING THEORY (Regulation 2008) (Common to Information Technology) Time: Three hours Answer ALL Questions. PART A- (10 X 2= 20 marks) Maximum:100 marks

1. Obtain the mean for a Geometric random variable. 2. What is meant by memoryless property? Which continuous distribution follows this property? 3. Give a real life example each for positive correlation and negative correlation. 4. State central limit theorem for independent and identically distributed (iid) random variables. 5. Is a Poisson process a continuous time Markov chain? Justify your answer. 6. Consider the Markov chain consisting of the three states 0, 1, 2 and transition probability matrix P= |1/2 1/2 0 | |1/2 1/4 1/4| |0 1/3 2/3| it irreducible? Justify. 7. Suppose that customers arrive at a Poisson rate of one per every 12 minutes and that the service time is exponential at a rate of one service per 8 minutes. What is the average number of customers in the system? 8. Define M/M/2 queuing model. Why the notation M is used? 9. Distinguish between open and closed networks.

10. M/G/1 queuing system is markovian. Comment on this statement.

PART B- (5 X 16 = 80 Marks)

11. (a) (i) By calculating the moment generating function of Poisson distribution with parameter , prove that the mean and variance of the Poisson distribution are equal.

(ii) If the density function of X equals f(x) = {Ce-2x , 0 < x < 0 , x2] ? (Or)

(b) (i) Describe the situations in which geometric distributions could be used. Obtain its moment generating function.

(ii) A coin having probability p of coming up heads is successively flipped until the rth head appears. Argue that X, the number of flips required will be n, n>= r with probability P[X = n] = (n-1) (r-1)pr qn-r n>=r

12. (a) (i) Suppose that X and Y are independent non negative continuous random variables having

densities fx(x) and fy(y) respectively. Compute P[X < Y].

(ii) The joint density of X and Y is given by f(x, y) = {1/2ye-xy , 0< x < , 0< y