Frames of 1000 bits are sent over a 1-Mbps channel using a geostationary satellite whose propagation time from the earth is 270 msec. Acknowledgements are always piggybacked onto data frames. The headers are very short. Three-bit sequence numbers are used. What is the maximum achievable channel utilization for

Suppose there is a relation r(a, b, c) with a b+-tree index with search keys (a, b).1. what is the worst-case cost of finding records satisfying 10 < a < 50 using this index, in terms of the number of records n1, retrieved and the height h of the tree? 2. what is the worst-case cost of finding records satisfying 10 < a < 50 and 5 < b < 10 using this index, in terms of the number of records n2 that satisfy this selection, as well as n1 and h defined above? 3. under what conditions on n1 and n2, would the index be an efficient way of finding records satisfying the condition from part (2)?

Assume a class window with accessor method getwidth that accepts no parameters and returns an integer. assume further an array of 3 window elements named winarr, has been declared and initialized. write a sequence of statements that prints out the width of the widest window in the array.

Write a program that uses a two-dimensional array to store the highest and lowest temperatures for each month of the year. the program should output the average high, average low, and the highest and lowest temper- atures for the year. your program must consist of the following functions: a. function getdata: this function reads and stores data in the two- dimensional array. b. function averagehigh: this function calculates and returns the average high temperature for the year. c. function averagelow: this function calculates and returns the aver- age low temperature for the year. d. function indexhightemp: this function returns the index of the highest high temperature in the array. e. function indexlowtemp: this function retur