When you tell an acquaintance your telephone number, you do not recite the digits one by one at a constant rate, as in "3, 3, 7, 2, 3, 4, 8, 3, 9, 2." Rather, you might say, "3, 3, 7 . . . 2, 3, 4 . . . 83, 92." This exemplifies , a strategy to enhance memory.

In a compound condition, both conditions on either side of the logical operator and must be true for the overall condition to be true. a: true b: false

Consider a slotted aloha system, where the time slot equals the fixed duration of each packet. assume that there are 4 stations a, b,c, d sharing the medium. (a) stations a, b,c, d receive one packet each from higher layers at times 1.3, 1.5, 2.6,5.7 respectively. show which transmissions take place when, according to the slottedaloha protocol; describe all transmissions until all four packets have been successful. when needed, each station has access to the following sequence of random number, provided by a random number generator and drawn uniformly between 0 and 1: (1) station a draws numbers: 0.31, 0.27, 0.78, 0.9, 0.9, 0.11, 0. (2) station b draws numbers: 0.45, 0.28, 0.11, 0.83, 0.37, 0.22, 0. (3)station c draws numbers: 0.1, 0.2, 0.3, 0.4, 0. (4) station d draws numbers: 0.36, 0.77, 0.9, 0.1, 0.1, 0.1, 0.1, 0. (b) in slotted aloha, a station transmits in each time slot with a given probability. what probabilities would you assign to each of the four stations so as to: (i) maximize the efficiency of the protocol? (ii) maximize fairness among the four stations? (c) will the efficiency increase or decrease if we modify slotted aloha as follows: (i) get rid of slots and allow stations to transmit immediately? (ii) implement carrier sensing? (iii) implement collision detection? (iv) implement collision avoidance?

In deadlock avoidance using banker’s algorithm, what would be the consequence(s) of: (i) a process declaring its maximum need as maximum possible for each resource. in other words, if a resource a has 5 instances, then each process declares its maximum need as 5. (ii) a process declaring its minimum needs as maximum needs. for example, a process may need 2-5 instances of resource a. but it declares its maximum need as 2.