A pointing device that has a laser guide on its underside and two or more buttons for clicking commands; you control the movement of the pointer by moving the entire thing around on your desk.

Awide variety of “ apps “ are available to customize devices. which category of app does the word processing software fall into?

What is wi-fi infrastructure? a metropolitan area network that uses radio signals to transmit and receive data a communications technology aimed at providing high-speed wireless data over metropolitan area networks a means by which portable devices can connect wirelessly to a local area network, using access points that send and receive data via radio waves includes the inner workings of a wi-fi service or utility, including the signal transmitters, towers, or poles and additional equipment required to send out a wi-fi signal

The idea that, for each pair of devices v and w, there’s a strict dichotomy between being “in range” or “out of range” is a simplified abstraction. more accurately, there’s a power decay function f (·) that specifies, for a pair of devices at distance δ, the signal strength f(δ) that they’ll be able to achieve on their wireless connection. (we’ll assume that f (δ) decreases with increasing δ.) we might want to build this into our notion of back-up sets as follows: among the k devices in the back-up set of v, there should be at least one that can be reached with very high signal strength, at least one other that can be reached with moderately high signal strength, and so forth. more concretely, we have values p1 ≥ p2 ≥ . . ≥ pk, so that if the back-up set for v consists of devices at distances d1≤d2≤≤dk, thenweshouldhavef(dj)≥pj foreachj. give an algorithm that determines whether it is possible to choose a back-up set for each device subject to this more detailed condition, still requiring that no device should appear in the back-up set of more than b other devices. again, the algorithm should output the back-up sets themselves, provided they can be found.\