Rephael Wenger

\Lambda, (2008)

Boris Aronov, Jacob E. Goodman, Richard Pollack, Rephael Wenger

Abstract Let S be a family of compact convex sets in Rd. Let D(S)be the largest diameter of any member of S. The family S is e-separated if, for every 0! k! d, any k of thesets can be separated from...

Running Title: Contour Area Filtering of RLGS Profiles (2008)

Ramakrishnan Kazhiyur-mannar, Dominic J Smiraglia, Christoph Plass, Rephael Wenger

Restriction Landmark Genome Scanning (RLGS) is a 2-dimensional gel electrophoresis technique for detecting DNA molecular changes that occur within restriction fragments. A typical RLGS profile...

© The Eurographics Association 2005. Time-Varying Interval Volumes (2008)

E. Gröller, I. Fujishiro (editors, Caixia Zhang, Daqing Xue, Roger Crawfis, Rephael Wenger

In this paper, we study the interval segmentation and direct rendering of time-varying volumetric data to provide a more effective and interactive volume rendering of time-varying structured and...

ABSTRACT Time-Varying Interval Volumes (2008)

Caixia Zhang, Daqing Xue, Roger Crawfis, Rephael Wenger

In this paper, we study the interval segmentation and direct rendering of time-varying volumetric data to provide a more effective and interactive volume rendering of time-varying structured and...

ABSTRACT Volume Interval Segmentation and Rendering (2008)

Praveen Bhaniramka, Caixia Zhang, Daqing Xue, Roger Crawfis, Rephael Wenger

In this paper, we segment the volume into geometrically disjoint regions that can be rendered to provide a more effective and interactive volume rendering of structured and unstructured grids. Our...

ALGORITHMS FOR LINE TRANSVERSALS IN SPACE Preliminary Report (2008)

David Avis, Rephael Wenger

Algorithms are developed for determining if a set of polyhedral objects in R 3 can be intersected by a common transversal (stabbing) line. It can be determined in O(n) time if a set of n lines in...

Restriction Landmark Genomic Scanning (RLGS) spot identification by second generation virtual RLGS in multiple genomes with multiple enzyme combinations (2007)

Smiraglia, Dominic J, Kazhiyur-Mannar, Ramakrishnan, Oakes, Christopher C, Wu, Yue-Zhong, Liang, Ping, Ansari, Tahmina, ...

Abstract Background Restriction landmark genomic scanning (RLGS) is one of the most successfully applied methods for the identification of aberrant CpG island hypermethylation in cancer, as well as...

Marching Cubes in Four and Higher Dimensions: Extended Abstract (2007)

Praveen Bhaniramka, Roger Craw, Ho-seok Kang, Donglin Liang, Rephael Wenger, Zhi Yao

Praveen Bhaniramka Roger Craws Ho-Seok Kang DongLin Liang Rephael Wenger Zhi Yao The Ohio State University Columbus, Ohio Abstract The marching cubes algorithm is a popular visualization algorithm...

Marching Cubes in Four and Higher Dimensions (Extended Abstract) (2007)

Praveen Bhaniramka, Roger Crawfis, Ho-seok Kang, DongLin Liang, Rephael Wenger, Zhi Yao

Praveen Bhaniramka Roger Craws Ho-Seok Kang DongLin Liang Rephael Wenger Zhi Yao The Ohio State University Columbus, Ohio Abstract The marching cubes algorithm is a popular visualization algorithm...

Anisotropic surface meshing (2006)

Cheng, Siu-Wing, Dey, Tamal K., Ramos, Edgar A., Wenger, Rephael

We study the problem of triangulating a smooth closed implicit surface Σ endowed with a 2D metric tensor that varies over Σ. This is commonly known as the anisotropic surface meshing problem. We...

Reconstructing curves with sharp corners (2001)

Tamal K. Dey, Rephael Wenger

In this paper we present a new algorithm for curve reconstruction that has multiple applications in image processing, geographic information systems, pattern recognition and mathematical modeling....

Undersampling and oversampling in sample based shape modeling (2001)

Tamal K. Dey, Joachim Giesen, Samrat Goswami, James Hudson, Rephael Wenger, Wulue Zhao

Shape modeling is an integral part of many visualization problems. Recent advances in scanning technology and a number of surface reconstruction algorithms have opened up a new paradigm for modeling...

Undersampling and Oversampling in Sample Based Shape Modeling (2001)

Tamal K. Dey, Joachim Giesen, Samrat Goswami, James Hudson, Rephael Wenger, Wulue Zhao

Shape modeling is an integral part of many visualization problems. Recent advances in scanning technology and a number of surface reconstruction algorithms have opened up a new paradigm for modeling...

Isosurfacing in higher dimensions (2000)

Praveen Bhaniramka, Rephael Wenger, Roger Crawfis

Visualization algorithms have seen substantial improvements in the past several years. However, very few algorithms have been developed for directly studying data in dimensions higher than three....

Reconstructing Curves with Sharp Corners (2000)

Tamal K. Dey, Rephael Wenger

In this paper we present a heuristic to reconstruct non-smooth curves with multiple components. Experiments with several input data reveals the eectiveness of the algorithm in contrast with the other...

Embedding Planar Graphs at Fixed Vertex Locations (1998)

Pach, János, Wenger, Rephael

Let G be a planar graph of n vertices, v_1, \ldots, v_n, and let {p_1, \ldots, p_n} be a set of n points in the plane. We present an algorithm for constructing in O(n²) time a planar embedding of G,...

Embedding Planar Graphs at Fixed Vertex Locations (1998)

Pach, János, Wenger, Rephael

Let G be a planar graph of n vertices, v_1, \ldots, v_n, and let {p_1, \ldots, p_n} be a set of n points in the plane. We present an algorithm for constructing in O(n²) time a planar embedding of G,...

Embedding Planar Graphs at Fixed Vertex Locations (1998)

Pach, János, Wenger, Rephael

Let G be a planar graph of n vertices, v_1, \ldots, v_n, and let {p_1, \ldots, p_n} be a set of n points in the plane. We present an algorithm for constructing in O(n²) time a planar embedding of G,...

Progress in geometric transversal theory (1998)

Rephael Wenger

Let A be a family of convex sets in R d. A line transversal to A is a line which intersects every member of A. More generally, a k-tranversal to A is an ane subspace of dimension k which intersects...

Constructing pairwise disjoint paths with few links (1997)

Himanshu Gupta, Rephael Wenger

Abstract. Let P be a simple polygon and let f(u i; u 0 i)g be m pairs of distinct vertices of P where for every distinct i; j m, there exist pairwise disjoint paths connecting u i to u 0 i and u j to...

Optimization of a Class of Multi-Dimensional Integrals on Parallel Machines (1997)

Chi-Chung Lam, P. Sadayappan, Rephael Wenger

Multi-dimensional summations involving products of arrays arise in certain kinds of computational physics calculations that model electronic structure. Besides the issue of optimal distribution of...

On optimizing a class of multi-dimensional loops with reductions for parallel execution (1997)

Chi-chung Lam, P. Sadayappan, Rephael Wenger

This paper addresses the compile-time optimization of a form of nested-loop computation that is motivated by a computational physics application. The computations involve multi-dimensional surface...

Helly-Type Theorems and Geometric Transversals (1997)

Rephael Wenger

INTRODUCTION A geometric transversal is an affine subspace of R d , such as a point, line, plane or hyperplane, which intersects every member of a family of convex sets. Eduard Helly's...

Constructing Pairwise Disjoint Paths with Few Links (1997)

Himanshu Gupta Rephael, Himanshu Gupta, Rephael Wenger

Let P be a simple polygon and let f(u i ; u 0 i )g be m pairs of distinct vertices of P where for every distinct i; j m, there exist pairwise disjoint paths connecting u i to u 0 i and u j to u 0 j ....

Constructing Piecewise Linear Homeomorphisms (1997)

By Diane Souvaine, Diane L. Souvaine, Rephael Wenger

Let P = fp 1 ; : : : ; p n g and Q = fq 1 ; : : : ; q n g be two point sets lying in the interior of rectangles in the plane. We show how to construct a piecewise linear homeomorphism of size O(n 2 )...

On the Connected Components of the Space of Line Transversals to a Family of Convex Sets (1997)

Jacob E. Goodman, Richard Pollack, Rephael Wenger

Let L be the space of line transversals to a finite family of pairwise disjoint compact convex sets in R 3 . We prove that each connected component of L can itself be represented as the space of...

Constructing Piecewise Linear Homeomorphisms (1997)

Diane Souvaine, Rephael Wenger

Let P = fp 1 ; : : : ; png and Q = fq 1 ; : : : ; q ng be two point sets lying in the interior of rectangles in the plane. We show how to construct a piecewise linear homeomorphism of size O(n 2 )...

Constructing pairwise disjoint paths with few links (1997)

Himanshu Gupta, Rephael Wenger

Let P be a simple polygon and let {(u1, u ′ 1), (u2, u ′ 2),..., (um, u ′ m)} be a set of m pairs of distinct vertices of P where for every distinct i, j ≤ m, there exist pairwise disjoint...

Optimal Reordering and Mapping of a Class of NestedLoops for Parallel Execution (1996)

Chi-Chung Lam, P. Sadayappan, Rephael Wenger

This paper addresses the compile-time optimization of a class of nested-loop computations that arise in some computational physics applications. The computations involve summations over products of...

An Approximation Algorithm for Computing Minimal Nonintersecting Link Paths (1996)

Himanshu Gupta, Rephael Wenger

Let P be a simple polygon and let f(u i ; u 0 i )g be m pairs of distinct vertices of P where for every distinct i; j m, there exist pairwise disjoint paths connecting u i to u 0 i and u j to u 0 j ....

Oriented Matroids and Hyperplane Transversals (1995)

Oriented Matroids, Hyperplane Transversals, Laura Anderson, Rephael Wenger

We prove that a finite family A of compact connected sets in R d has a hyperplane transversal if and only if for some k, 0 k ! d, there exists an acyclic oriented matroid of rank k+1 on A such that...

Constructing Piecewise Linear Homeomorphisms of Simple Polygons (1995)

Himanshu Gupta, Rephael Wenger, Rephael Wenger

Let P and Q be simple polygons with vertex sets fp1 ; : : : ; png and fq1 ; : : :, qng, respectively. We present an algorithm to construct a piecewise linear homeomorphism between P and Q mapping...

Constructing Piecewise Linear Homeomorphisms of Simple Polygons (1995)

Himanshu Gupta, Rephael Wenger

Let P and Q be simple polygons with vertex sets fp1 ; : : : ; png and fq1 ; : : :, qng, respectively. We present an algorithm to construct a piecewise linear homeomorphism between P and Q mapping...

Stabbing and separation / (1988)

Wenger, Rephael.

Written for the School of Computer Science.

On the Helly Number for Hyperplane Transversals to Unit Balls

Boris Aronov, Jacob E. Goodman, Richard Pollack, Rephael Wenger

We prove some results about the Hadwiger problem of finding the Helly number for line transversals of disjoint unit disks in the plane, and about its higher-dimensional generalization to hyperplane...