Jamaal has to make an important phone call. unfortunately, the battery in his cell phone is very low, so he has to use his landline, which does not store phone numbers. to make the call, he has to get the number from his cell phone and remember it long enough to use his landline. for this task, which memory system is most important? a. working memory b. sensory memory c. short-term memory d. long-term memory

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?

What is the total resistance in a circuit that contains three 60 ohm resistors connected in a series? a. 20 ohms b. 120 ohms c. 60 ohms d. 180 ohms

The song about casey jones a railroad engineer who gives his life on the job would most likely gall under the folk song category of? a-work song b-nonsense song c-religious song d-ballad