Which of the following types of relationships can a relational database not define?
a zero-to-many
b one-to-one
c many-to-many
d one-to-many

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 allows you to create a wireless connection among your smart devices

Problem 1 - hashing we would like to use initials to locate an individual. for instance, mel should locate the person mark e. lehr. note: this is all upper case. generate a hash function for the above using the numbers on your telephone. you know, each letter has a number associated with it, so examine your telephone keypad. generate 512 random 3 letter initials and take statistics on a linked list array size 512 to hold this information report how many have no elements, 1 element, 2 elements, does this agree with the hashing statistics distribution?