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- J Sellen, J E Hopcroft, J T Schwartz, M Sharir, R R ? H H H Y
- 1996

The opposite direction, that for any given P, e, h and q, the language L satisfying (2) is Turing-computable, follows from the fact that we can enumerate all points of P that are reachable from a given point 2 e (the algorithm has to follow the structure of P inductively, simplex for simplex, by marking the already detected reachable areas). 5. Future work.… (More)

- Elmar Schömer, Jürgen Sellen, Marek Teichmann, Chee-Keng Yap
- Algorithmica
- 1996

This paper addresses the complexity of computing the smallest-radius infinite cylinder that encloses an input set of n points in 3-space. We show that the problem can be solved in time O(n 4 log O(1) n) in an algebraic complexity model. We also achieve a time of O(n 4 L⋅μ(L)) in a bit complexity model where L is the maximum bit size of input numbers and… (More)

- Frank Follert, Elmar Schömer, Jürgen Sellen, Michiel H. M. Smid, Christian Thiel
- Int. J. Comput. Geometry Appl.
- 1995

Let S be a set of n points in IR d , and let each p o i n t p of S have a p o s i t i v e weight w(p). We consider the problem of computing a ray R emanating from the origin (resp. a line l through the origin) such that min p2S w(p) d(pp R) (resp. min p2S w(p) d(pp l)) is maximal. If all weights are one, this corresponds to computing a silo emanating from… (More)

- Joonsoo Choi, Jürgen Sellen, Chee-Keng Yap
- Int. J. Comput. Geometry Appl.
- 1994

Papadimitriou's approximation approach to the Euclidean shortest path (ESP) problem in 3-space is revisited. As this problem is NP-hard, his approach represents an important step towards practical algorithms. Unfortunately, there are non-trivial gaps in the original description. Besides giving a complete treatment, we also give an alternative to his… (More)

- Joonsoo Choi, Jürgen Sellen, Chee-Keng Yap
- Symposium on Computational Geometry
- 1995

This paper introduces the concept of precision-sensitive algorithms, in analogy to the well-known output-sensitive algorithms. We exploit this idea in studying the complexity of the 3-dimensional Euclidean shortest path problem. Specifically, we analyze an in-cremental approximation approach based on ideas in [CSY], and show that this approach yields an… (More)

- Jürgen Sellen
- ICRA
- 1995

- Jürgen Sellen
- ICRA
- 1995

- Jürgen Sellen
- Intelligent Robots
- 1996

Exact computation is an important paradigm for the implementation of geometric algorithms. In this paper, we consider for the first time the practically important problem of collision detection under this aspect. The task is to decide whether a polyhedral object can perform a prescribed sequence of translations and rotations in the presence of stationary… (More)

- Frank Follert, Elmar Schömer, Jürgen Sellen
- CCCG
- 1995

Let S be a set of n points in the plane, and let each point p of S have a positive weight w(p). We consider the problem of positioning a point x inside a compact region R ⊆ R 2 such that min{ w(p) −1 · d(x, p) ; p ∈ S } is maximized. Based on the parametric search paradigm, we give the first subquadratic algorithms for this problem, with running time O(n… (More)