This paper presents a composite programmable graph grammar model of the three dimensional self-adaptive hp Finite Element Method (hp-FEM) algorithms. The computational mesh composed of hexahedral finite elements is represented by a composite graph. The operations performed over the mesh are expressed by composite graph grammar productions. The three dimensional model is based on the extension o...

In order to realize massive point cloud data simplification, a new movable mesh generation algorithm was proposed. Firstly, point cloud model was divided into a number of spatial grids. Secondly, the mesh generation was made like the first step again but more finely and with respecting of the distance threshold, and then, each appropriate point of the grids generated by the second step was filt...

A new computational method for creating all-hex meshes of thin-walled solids is presented. The proposed method creates an all-hex mesh in a three-step process. First, a tet mesh of the target geometric domain is created, and a layer of prism elements is inserted on the boundary of the mesh. Second, a sequence of novel topological transformations and smoothing operations is applied to reduce the...

Although explicit time integration schemes require small computational efforts per time step, their efficiency is severely restricted by their stability limits. Indeed, the multi-scale nature of some physical processes combined with highly unstructured meshes can lead some elements to impose a severely small stable time step for a global problem. Multirate methods offer a way to increase the gl...

We discuss an optimization procedure for improving three-dimensional finite element meshes. Our method can be effectively coupled with any automatic mesh generator in order to obtain a triangulation without badly distorted elements. In this way, we are able to weaken the requirements on the generator, allowing it to produce singular elements, and post-process the result to get a valid mesh. Eve...

SSs (Subdivision Surfaces) are a powerful modelling paradigm for truly hierarchical (instead of merely progressive) 3D surface (as opposed to mesh) coding. Two SS-based tools of MPEG-4’s Animation Framework eXtension allow to derive a piecewise smooth surface from an initial control mesh: if the subdivision process is run in its predefined form, the initial mesh is simply smoothed; if 3D detail...

We propose new authentication protocols to support fast handover in IEEE 802.11-based wireless mesh networks. The authentication server does not need to be involved in the handover authentication process. Instead, mesh access points directly authenticate mobile clients using tickets, avoiding multi-hop wireless communications in order to minimize the authentication delay. Numerical analysis and...

MEDLINE indexing performed by the US National Library of Medicine staff describes the essence of a biomedical publication in about 14 Medical Subject Headings (MeSH). Since 2002, this task is assisted by the Medical Text Indexer (MTI) program. We present a bottom-up approach to MEDLINE indexing in which the abstract is searched for indicators for a specific MeSH recommendation in a two-step pro...

We propose an automatic algorithm for the reconstruction of a set of patient-specific dynamic cardiac mesh model with 1-to-1 mesh correspondence over the whole cardiac cycle. This work focus on both the reconstruction technique of the initial 3D model of the heart and also the consistent mapping of the vertex positions throughout all the 3D meshes. This process is technically more challenging d...

The Finite Element Method is a powerful numerical technique for solving ordinary and partial differential equations in a range of complex science and engineering applications, such as multi-domain analysis and structural engineering. It involves decomposing the analysis domain into a discrete mesh before constructing and then solving a system of equations built over mesh elements. The number of...