WiPSCE '16: Proceedings of the 11th Workshop in Primary and Secondary Computing Education, WiPSCE 2016, Münster, Germany, October 13-15, 2016

Item does not contain fulltextWiPSCE '16: The 11th Workshop in Primary and Secondary Computing Education, WiPSCE 2016, Münster, Germany, October 13-15, 2016124 p

Steinitz theorems for orthogonal polyhedra

No abstract

Approximation algorithms for free-label maximization

Inspired by applications where moving objects have to be labeled, we consider the following (static) point labeling problem: given a set P of n points in the plane and labels that are unit squares, place a label with each point in P in such a way that the number of free labels (labels not intersecting any other label) is maximized. We develop efficient constant-factor approximation algorithms for this problem, as well as PTASs, for various label-placement models

Finding structures on imprecise points

An imprecise point is a point in R^2 of which we do not know the location exactly; we only know for each point a region in R^2 containing it. On such a set of imprecise points, structures like the closest pair or convex hull are not uniquely defined. This leads us to study the following problem: Given a structure of interest, a set R of regions and a subset C ¿ R, we want to determine if it is possible to place a point in each region of R such that the points placed in regions of C form the structure of interest. We study this problem for the convex hull, with various types of regions. For each variant we either give a NP-hardness proof or a polynomial-time algorithm

Hiding in the crowd: asympstotic bounds on blocking sets

We consider the problem of blocking all rays emanating from a unit disk U by a minimum number N_d of unit disks in the two-dimensional space, where each disk has at least a distance d to any other disk. We study the asymptotic behavior of N_d, as d tends to infinity. Using a regular ordering of disks on concentric circular rings we derive upper and lower bounds and prove that $\frac{\pi^2}{16} \leq \frac{N_d}{d^2} \leq \frac{\pi^2}{2}$, as d goes to infinity

Hiding in the crowd: asympstotic bounds on blocking sets

We consider the problem of blocking all rays emanating from a unit disk U by a minimum number N_d of unit disks in the two-dimensional space, where each disk has at least a distance d to any other disk. We study the asymptotic behavior of N_d, as d tends to infinity. Using a regular ordering of disks on concentric circular rings we derive upper and lower bounds and prove that $\frac{\pi^2}{16} \leq \frac{N_d}{d^2} \leq \frac{\pi^2}{2}$, as d goes to infinity

The CECE Report: Creating a Map of Informatics in European Schools

https://doi.org/10.1145/3159450.315963

Space-Efficient Geometric Divide-and-Conquer Algorithms

We present an approach to simulate divide-and-conquer algorithms in a space-efficient way, and illustrate it by giving space-efficient algorithms for the closest-pair, bichromatic closest-pair, all-nearest-neighbors, and orthogonal line segment intersection problems

Reporting intersecting pairs of convex polytopes in two and three dimensions

Let P={P(1),.....,P(m)) be a set of m convex polytopes in , for d=2,3, with a total of n vertices. We present output-sensitive algorithms for reporting all k pairs of indices (i,j) such that Pi intersects Pj. For the planar case we describe a simple algorithm with running time O(n4/3log2+n+k), for any constant >0, and an improved randomized algorithm with expected running time O((nlogm+k)a(n)logn) (which is faster for small values of k). For d=3, we present an O(n8/5++k)-time algorithm, for any >0. Our algorithms can be modified to count the number of intersecting pairs in O(n4/3log2+n) time for the planar case, and in O(n8/5+) time for the three-dimensional case