/*judge whether the querier q satisfies quality monitor requirement*/ Function (Query s, q) const PI = 3.1415926 { double distance = 0; distance = the length from s to the center of cycle q distance += the length from s to the center of cycle q' If CA (s, q) < CA (s, q') then return true else return false; } ALGORITHM 3: Privacy monitor ft.
For the query shown in Figure 8(a), the arrow represents the possible biggest velocity of the queriers and the dashed cycle represents all possible positions of the queriers in the whole query life cycle.
Algorithm 2 prevents the queriers from getting too dispersive at the initial time, while for the problem where queriers might converge to one point, we have to solve it after k queriers are selected.