Statistical studies of languages have focused on the rank-frequency distribution of words. Instead, we introduce here a measure of how word ranks change in time and call this distribution rank diversity. We calculate this diversity for books published in six European languages since 1800, and find that it follows a universal lognormal distribution. Based on the mean and standard deviation assoc...

Traditional higher educational learning practise uses the information transfer model where knowledge is passed from the experts (tutors) to the learners (students) by means of lectures and text books. New educational models based on constructivism may be used in parallel with traditional learning introducing a blended (or enhanced) learning approach. In such a blended environment, organizationa...

Ambiguous and multifaceted queries widely exist in academic and commercial search engines. Identifying the popular subtopics of queries is an important issue for search engines. In this paper, we propose a novel method to discover the popular subtopics for a given query. Our method first constructs a search behavior tripartite graph based on the search log data. Then, we utilize a subtractive i...

We present an average-case complexity analysis for the zerofinding problem for functions from C([0, 1]), r > 2 , which change sign at the endpoints. This class of functions is equipped with a conditional r-folded Wiener measure. We prove that the average-case complexity of computing an «-approximation is of order log log( 1 /e), and that a hybrid secant-bisection method with a suitable adaptive...

The geometric thickness of a graph is the minimum number of layers such that the graph can be drawn in the plane with edges as straight-line segments, and with each edge assigned to a layer so that no two edges in the same layer cross. We consider a variation on this theme in which each edge is allowed one bend. We prove that the vertices of an n-vertex m-edge graph can be positioned in a √n × ...

We present a deterministic algorithm running in space O ? log 2 n= log logn solving the connectivity problem on strongly unambiguous graphs. In addition, we present an O(logn) time-bounded algorithm for this problem running on a parallel pointer machine.