the points is represented by a nail sticking out of a board the convex hull is the polygon obtained by extending a rubber band around the set of points there are many well known algorithms for finding the convex hull of a set of points by taking advantage of the fact that the points are sorted from left to right in increasing order of their x coordinate we construct the following algorithm to find the lower convex hull of a set of points the algorithm is written in terms of a set q of points the algorithm finishes in time which is linear in the number of points in q let p 0 be the point in q with the minimum x coordinate or the highest let lt p 1 p m gt be the remaining points in q sorted by x coordinate from p 0 if more that one point has the same x coordinate remove while p i is below the line formed by the points next to top s fig6 is a graph depicting the basic operation of a preferred embodiment of the present invention an affine function 600 is a close approximation of a lower bound on data points 601 which are measured delays between two network connected data processing systems affine function 600 is determined.