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Three Rules Suffice for Good Label Placement
 Algorithmica Special Issue on GIS
, 2000
"... The general labelplacement problem consists in labeling a set of features (points, lines, regions) given a set of candidates (rectangles, circles, ellipses, irregularly shaped labels) for each feature. The problem arises when annotating classical cartographical maps, diagrams, or graph drawings. Th ..."
Abstract

Cited by 18 (2 self)
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The general labelplacement problem consists in labeling a set of features (points, lines, regions) given a set of candidates (rectangles, circles, ellipses, irregularly shaped labels) for each feature. The problem arises when annotating classical cartographical maps, diagrams, or graph drawings. The size of a labeling is the number of features that receive pairwise nonintersecting candidates. Finding an optimal solution, i.e. a labeling of maximum size, is NPhard. We present an approach to attack the problem in its full generality. The key idea is to separate the geometric part from the combinatorial part of the problem. The latter is captured by the conflict graph of the candidates. We present a set of rules that simplify the conflict graph without reducing the size of an optimal solution. Combining the application of these rules with a simple heuristic yields nearoptimal solutions. We study competing algorithms and do a thorough empirical comparison on pointlabeling data. The new algorithm we suggest is fast, simple, and effective.
Towards WebBased Computing
, 1999
"... In a problem solving environment for geometric computing, a graphical user interface, or GUI, for visualization has become an essential component for geometric software development. In this paper we describe a visualization system, called GeoJAVA, which consists of a GUI and a geometric visualiza ..."
Abstract

Cited by 4 (1 self)
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In a problem solving environment for geometric computing, a graphical user interface, or GUI, for visualization has become an essential component for geometric software development. In this paper we describe a visualization system, called GeoJAVA, which consists of a GUI and a geometric visualization library that enables the user or algorithm designer to (1) execute and visualize an existing algorithm in the library or (2) develop new code over the Internet. The library consists of geometric code written in C/C++. The GUI is written using the Java programming language. Taking advantage of the socket classes and systemindependent application programming interfaces (API's) provided with the Java language, GeoJAVA oers a platform independent environment for distributed geometric computing that combines Java and C/C++. Users may remotely join a \channel" or discussion group in a location transparent manner to do collaborative research. The visualization of an algorithm, a C/C+...
Contents
, 1996
"... We describe the implementation of the LEDA [MN95, Nah95] data type real. Every integer is a real and reals are closed under the operations addition, subtraction, multiplication, division and squareroot. The main features of the data type real are The user{interface is similar to that of the built{i ..."
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We describe the implementation of the LEDA [MN95, Nah95] data type real. Every integer is a real and reals are closed under the operations addition, subtraction, multiplication, division and squareroot. The main features of the data type real are The user{interface is similar to that of the built{in data type double. All comparison operators f>;; <;;=g are exact. In order to determine the sign of a real number x the data type rst computes a rational number q such that jxj q implies x = 0 and then computes an approximation of x of sucient precision to decide the sign of x. The user may assist the data type by providing a separation bound q. The data type also allows to evaluate real expressions with arbitrary precision. One may either set the mantissae length of the underlying
oating point system and then evaluate the expression with that mantissa length or one may specify an error bound q. The data type then computes an approximation with absolute error at most q.
No Title Given
"... . Frames will provide support for the programming of distributed memory machines via a library of basic algorithms, data structures and socalled programming frames (or frameworks). The latter are skeletons with problem dependent parameters to be provided by the users. Frames focuses on reusabi ..."
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. Frames will provide support for the programming of distributed memory machines via a library of basic algorithms, data structures and socalled programming frames (or frameworks). The latter are skeletons with problem dependent parameters to be provided by the users. Frames focuses on reusability and portability as well as on small and easytolearn interfaces. Thus, expert and nonexpert users will be provided with tools to program and exploit parallel machines eciently. Frames will be constructed for dierent target machines and common programming environments (like PVM or MPI). The focus, however, is on distributedmemory machines. Frames will be adapted optimally to the target systems, contain ecient stateoftheart programming techniques, and therefore increase the usability and therefore the acceptance of parallel computing. Key words: Eciency, Reusability, Portability, stateoftheart algorithms, Templates, Skeletons, Frames 1 Motivation Parallel computing s...