Abstract. The kernel of a polygon P is the set of all points that see the interior of P. It can be computed as the intersection of the halfplanes that are to the left of the edges of P. We present an...
The Edge- ipping Distance of Triangulations (2008)
Sabine Hanke, Thomas Ottmann, Sven Schuierer
Abstract: An edge- ipping operation in a triangulation T of a set of points in the plane is a local restructuring that changes T into a triangulation that di ers from T in exactly one edge. The edge-...
The Exact Cost of Exploring Streets with a CAB (Extended Abstract) (2008)
A. López-Ortiz, Alejandro Lopez-ortiz, Sven Schuierer
Alejandro Lopez-Ortiz + Sven Schuierer # Abstract A fundamental problem in robotics is to compute a path for a robot from its current location to a given target. In this paper we consider the problem...
Restricted Orientation Visibility (2007)
Sven Schuierer, Derick Wood, Of O
Let O be some set of orientations, i.e., O ` [0 ffi; 360 ffi). In this paper we look at the consequences of defining visibility based on curves that are monotone w.r.t. to the orientations in O. We...
The edge-flipping distance of triangulations Institut fur Informatik--- Report 76 (2007)
Sabine Hanke, Thomas Ottmann, Sven Schuierer
Figure 1: An edge-flipping operation replacing e An edge-flipping operation in a triangulation T of a set of points in the plane is a local restructuring that changes T into a triangulation that...
Christoph A. Hipke, Sven Schuierer
user-centered approach to the distributed visualization of geometric algorithms
Delaunay Triangulations and the Radiosity Approach (2007)
The radiosity approach requires the subdivision of complex surfaces into simple components called patches. Since we assume to have constant intensity over a patch, the generation of regular patches...
Optimal Algorithms for Stabbing Polygons by Monotone Chains (2007)
Vladimir Estivill-castro, Sven Schuierer
In this paper we present optimal algorithms to compute monotone stabbers for convex polygons. More precisely, given a set of m convex polygons with n vertices in total we want to stab the polygons...
The edge-flipping distance of triangulations Institut fur Informatik--- Report 76 (2007)
Sabine Hanke, Thomas Ottmann, Sven Schuierer
Figure 1: An edge-flipping operation replacing e An edge-flipping operation in a triangulation T of a set of points in the plane is a local restructuring that changes T into a triangulation that...
We consider the problem of searching on m current rays for a target of unknown location. If no upper bound on the distance to the target is known in advance, then the optimal competitive ratio is 1 +...
Lower Bounds For Randomized Searching on m Rays (2007)
We consider the problem of on-line searching on m rays. A point robot is assumed to stand at the origin of m concurrent rays one of which contains a goal g that the point robot has to reach. Neither...
Shortest m-Watchmen Routes for Histograms: The MinMax Case (2007)
Bengt J. Nilsson, Sven Schuierer
In this paper we consider the problem of computing an optimum set of watchmen routes in a histogram. A watchman, in the terminology of art galleries, is a mobile guard and in this version we want to...
Mikael Hammar, Bengt J. Nilsson, Sven Schuierer
Abstract. We investigate parallel searching on m concurrent rays. We assume that a target t is located somewhere on one of the rays; we are given a group of m point robots each of which has to reach...
The Exact Cost of Exploring Streets with a CAB Extended Abstract (2007)
A fundamental problem in robotics is to compute a path for a robot from its current location to a given target. In this paper we consider the problem of a robot equipped with an on-board vision...
Rudolf Fleischer, Kathleen Romanik, Sven Schuierer
The problem of localization, that is, of a robot finding its position on a map, is an important task for autonomous mobile robots. It has applications in numerous areas of robotics ranging from...
Parallel Searching on m Rays (2001)
Hammar, Mikael, Nilsson, Bengt J., Schuierer, Sven
We investigate parallel searching on $m$ concurrent rays. We assume that a target $t$ is located somewhere on one of the rays; we are given a group of $m$ point robots each of which has to reach $t$....
Parallel searching on m rays (2001)
Mikael Hammar, Bengt J. Nilsson, Sven Schuierer
In this paper we investigate parallel searching on m concurrent rays. We assume that a target t is located somewhere on one of the rays and that a group of m point robots has to reach t. Furthermore,...
Parallel Searching on m Rays (2001)
Mikael Hammar, Bengt J. Nilsson, Sven Schuierer
In this paper we investigate parallel searching on m concurrent rays. We assume that a target t is located somewhere on one of the rays and that a group of m point robots has to reach t. Furthermore,...
Optimal robot localization in trees (2000)
Rudolf Fleischer, Kathleen Romanik, Sven Schuierer
The problem of localization, that is, of a robot finding its position on a map, is an important task for autonomous mobile robots. It has applications in numerous areas of robotics ranging from...
Vega - A user-centered approach to the distributed visualization of geometric algorithms (1999)
Christoph A. Hipke, Sven Schuierer
We present a new approach to the distributed visualization of geometric algorithms that emphasizes the position of the end user. Concepts are introduced that enable a more flexible usage of...
The ultimate strategy to search on m rays (1998)
We consider the problem of searching on m current rays for a target of unknown location. If no upper bound on the distance to the target is known in advance, then the optimal competitive ratio is 1 +...
Searching on m bounded rays optimally (1998)
We consider the problem of searching on m current rays for a target of unknown location. It is well-known that the optimal strategy to solve this problem achieves a competitive ratio of Cm = 1 + 2m m
The exact cost of exploring streets with a CAB (1998)
A fundamental problem in robotics is to compute a path for a robot from its current location to a given target. In this paper we consider the problem of a robot equipped with an on-board vision...
Going Home Through an Unknown Street (1998)
Christian Icking, Alejandro López-Ortiz, Sven Schuierer, Christian Icking Alej, Ines Semrau
We present a new strategy for searching for a goal in a street. The strategy works in two phases. First it follows an angular bisector, then it uses circular arcs based only on one side of the...
On-line Searching in Simple Polygons (1998)
In this paper we study the problem of a robot searching for a visually recognizable target in an unknown simple polygon. We present two algorithms. Both work for arbitrarily oriented polygons. The...
Exploring Unknown Environments with Obstacles (1998)
Susanne Albers, Klaus Kursawe, Sven Schuierer
We study exploration problems where a robot has to construct a complete map of an unknown environment using a path that is as short as possible. In the first problem setting we consider, a robot has...
Multiple-Guard Kernels of Simple Polygons (1998)
We study a generalization of the kernel of a polygon. A polygon P is k guardable if there are k points in P such that, for all points p in P , there is at least one of the k points that sees p. We...
Efficient Robot Self-Localization in Simple Polygons (1997)
Introduction One of the basic tasks faced by an autonomous mobile robot is the problem of self-localization, that is determining its position in its environment; this is also sometimes called the...
Position-Independent Near Optimal Searching and On-line Recognition in Star Polygons (1997)
Alejandro Lopez-Ortiz, Sven Schuierer
. We study the problem of on-line searching for a target inside a polygon. In particular we propose a strategy for finding a target of unknown location in a star polygon with a competitive ratio of...
Multiple-guard kernels of simple polygons (1996)
A polygon P is k guardable if there are k points in P such that, for all points p in P, there is at least one of the k points that sees p. We call the k points a k-guard set of P and the k-kernel of...
We present a data structure that allows to preprocess a rectilinear polygon with n vertices such that, for any two query points, the shortest path in the rectilinear link or L 1-metric can be...
The Edge-flipping Distance of Triangulations (1996)
Sabine Hanke, Thomas Ottmann, Sven Schuierer
: An edge-flipping operation in a triangulation T of a set of points in the plane is a local restructuring that changes T into a triangulation that differs from T in exactly one edge. The...
Alejandro López-Ortiz, Sven Schuierer
A fundamental problem in robotics is to compute a path for a robot from its current location to a given goal. In this paper we consider the problem of a robot equipped with an on-board vision system...
Optimal Robot Localization in Trees (1996)
Kathleen Romanik, Sven Schuierer
The problem of localization, i.e. of a robot finding its position on a map, is an important task for autonomous mobile robots. It has applications in numerous areas of robotics ranging from aerial...
Visibility in semi-convex spaces (1995)
We introduce the notion of a semi-convex space as a unifying framework for the treatment of various notions of convexity in the plane Semi-convex spaces are a generalization of convexity spaces that...
Visibility in Semi-convex Spaces (1995)
We introduce the notion of a semi-convex space as a unifying framework for the treatment of various notions of convexity in the plane. Semi-convex spaces are a generalization of convexity spaces that...
Simple, Efficient and Robust Strategies to Traverse Streets (1995)
Alejandro López-Ortiz, Sven Schuierer
We present a family of strategies for the problem of searching in an unknown street for a target of unknown location. We show that a robot using a strategy from this family follows a path that is at...
Going Home Through an Unknown Street (1995)
Alejandro López-Ortiz, Sven Schuierer
We consider the problem of a robot traversing an unknown polygon with the aid of standard visibility. The robot has to find a path from a starting point s to a target point g. We provide upper and...
On generalized visibility / (1991)
Thesis (doctoral)--Albert-Ludwigs-Universität Freiburg im Breisgau, 1991.
An optimal algorithm for the rectilinear link center of a rectilinear polygon (1991)
Bengt J. Nilsson, Sven Schuierer
Abstract The link distance between two points in a polygon P is defined as the minimum number of line segments inside P needed to connect the two points. The link center of a polygon P is the set of...
An Optimal Algorithm for the Rectilinear Link Center of a Rectilinear Polygon (1991)
Bengt J. Nilsson, Sven Schuierer
The problem of finding the link center of a simple polygon has been studied extensively in recent years. O(n log n) time upper bounds have been given for this problem and that of computing the link...
Visibility in Semi-convex Spaces (1991)
In this paper we pursue the notion of a semi-convex space as a unifying framework for the treatment of various notions of convexity in the plane. In particular, we suggest how to capture the notion...