ISRO Scientist/Engineer Question Paper Computer Science 2018

41. Question

For a database relation R(a,b,c,d) where the domains of a, b, c and d include only atomic values, only the following functional dependencies and those that can be inferred from them hold
a -> c
b -> d
The relation is in

42. Question

Consider the set of relations given below and the SQL query that follows:
Students : ( Roll_number, Name, Date_of_birth )
Courses: (Course_number, Course_name, Instructor )
Grades: (Roll_number, Course_number, Grade)
FROM Students, Courses, Grades
WHERE Students.Roll_number = Grades.Roll_number
AND Courses.Instructor =Sriram
AND Courses.Course_number = Grades.Course_number
AND Grades.Grade = A
Which of the following sets is computed by the above query?

43. Question

Consider the following C++ program
int a (int m)
{ return ++m ; }
int b(int&m)
{ return ++m;}
intc(char &m)
{ return ++m ; }
void main ()
nt p = 0 , q=0, r = 0 ;
p += a(b(p)) ;
q+= b(a(q)) ;
r += a(c(r)) ;
out<< p <<q << r ;
Assuming the required header files are already included, the above program

44. Question

Station A uses 32 byte packets to transmit messages to Station B using a sliding window protocol. The round trip delay between A and B is 80 ms and the bottleneck bandwidth on the path between A and B is 128 kbps. What is the optimal window size that A should use?

45. Question

Assuming that for a given network layer implementation, connection establishment overhead is 100 bytes and disconnection overhead is 28 bytes. What would be the minimum size of the packet the transport layer needs to keep up, if it wishes to implement a datagram service above the network layer and needs to keep its overhead to a minimum of 12.5%. (Ignore transport layer overhead)