This paper proposes an effective algorithm based on the level set method (LSM) to solve shape and topology optimization problems. Since the conventional LSM has several limitations, a binary level set method (BLSM) is used instead. In the BLSM, the level set function can only take 1 and -1 values at convergence. Thus, it is related to phase-field methods. We don’t need to solve the Hamilton-Jac...

Background: Gold nanoparticles (GNPs) have been shown as a good radiosensitizer. In combination with radiotherapy, several studies with orthovoltage X-rays have shown considerable dose enhancement effects. This paper reports the dose enhancement factor (DEF) due to GNPs in 18 megavoltage (MV) beams. Materials and Methods: Different geometrical 50-nm GNPs configurations at a concentrati...

An adaptive regularized level set method for image segmentation is proposed. A weighted p x Dirichlet integral is presented as a geometric regularization on zero level curve, which is used to diminish the influence of image noise on level set evolution while ensuring the active contours not to pass through weak object boundaries. The idea behind the new energy integral is that the amount of reg...

This paper presents an object-oriented approach for describing and modelling buildings by means of computer graphics. The approach is based on an objectand component-oriented graphics framework. Scenes of buildings are conventionally modelled by a set of primitives and some aggregates. The present approach, however, uses highly abstract objects which represent certain parts of real buildings. T...

Editing and deformation of irregular meshes have become standard tools in geometric modeling. Most approaches try to preserve low-level differential properties of the surface during editing, whereas the global structure and shape of the features are not explicitly taken into account. In this paper, we introduce a feature-driven editing approach that puts global structural properties of the shap...

Motion of curves governed by geometric evolution laws, such as mean curvature flow and surface diffusion, is the basis for many algorithms in image processing. If the images to be processed are defined on nonplanar surfaces, the geometric evolution laws have to be restricted to the surface and turn into geodesic evolution laws. In this paper we describe efficient algorithms for geodesic mean cu...

The theory of simplicial sets and their realization is perhaps the basis to the combinatorial approach to homotopy theory. The construction of the geometric realization is very natural except for one thing: It begins with the postulation of the geometric realization of each of the “standard simplices”, to which no justification is given. It occurred to us that by “explaining” the nature of this...