Unorganized point classification for robust NURBS surface reconstruction using a point-based neural network

In this paper, a method for classifying 3D unorganized points into interior and boundary points using a deep neural network is proposed. The classification of 3D unorganized points into boundary and interior points is an important problem in the nonuniform rational B-spline (NURBS) surface reconstruction process. A part of an existing neural network PointNet, which processes 3D point segmentation, is used as the base network model. An index value corresponding to each point is proposed for use as an additional property to improve the classification performance of the network. The classified points are then provided as inputs to the NURBS surface reconstruction process, and it has been demonstrated that the reconstruction is performed efficiently. Experiments using diverse examples indicate that the proposed method achieves better performance than other existing methods.

Quasi-Isotropic Initial Triangulation of NURBS Surfaces

Isotropic triangulation of NURBS surfaces provides high quality triangular meshes, where all triangles are equilateral. This isotropy increases representation quality and analysis accuracy. We introduce a new algorithm to generate quasi-isotropic triangulation on NURBS surfaces at once, with no prior meshing. The procedure consists of one front made of vertexes that advances in a divergence manner avoiding front collision. Vertexes are calculated by arcs intersection whose radius length is estimated by trapezoidal rule integration of directional derivatives. The parameter space is discretized in partitions such that the error of trapezoidal rule is controlled. A new space, called pattern space, is used to infer the direction of the arcs intersection. Derivatives, whose analytical computation is expensive, are estimated by NURBS surface fitting procedures, which raise the speed of the process. The resultant algorithm is robust and efficient. The mesh achieved possesses most of the triangles equilateral and with high uniformity of sizes. The performance is illustrated by measuring angles, vertex valences and size uniformity in numerical examples

The Researches and Applications of Reverse Engineering in the Protection and Inheritance of National Handcrafts

National handcrafts are well-known at home and Abroad for their fine ingredients, exquisite blending of colors, and excellent skilled shaping and painting. What is more, they have great value and are deeply popular with people around the world. National handcrafts, as a cultural crystallization, must be protected. In order to better realize the protection, we try to apply the technology of reverse engineering to the protection. This article mainly takes a handcraft, Yan Zi YU (meaning “swallow fish”), as an example to expound and demonstrate the process of reverse engineering technology. During this process, by using scanning technology of reverse engineering, the collection and splicing of the point cloud data, the theoretical analysis of the NURBS surface in the reconstruction phase, and other practical operations in other stages, reverse engineering can be used to regenerate 3D modal data of the swallow fish and to inspect and analyse the errors in it through Geomagic Quality to ensure that the new model meets the precision requirements. Therefore, the reverse engineering technology can be completely applied to the protection of national handcrafts so that they can fully demonstrate their own value and function. If the precision of reverse engineering detection can reach nanometric level, a breakthrough will promote the protection of cultural relics.

AN INNOVATIONAL DIGITAL TOOL IN GIS PROCEDURE: MAPPING ADRIATIC COAST IN ABRUZZO REGION TO SUPPORT DESIGN OF SLOW MOBILITY ROUTES

The research work, object of this paper, is included in the "Fragile Territories" project of the Department of Architecture and Urban Studies of the Politecnico di Milano. It addresses the problem of mapping a territory, starting from the case studies of this issue in the contemporary scientific literature and trying to solve them by available raster/vector GIS database. The first innovation introduced with this research is the coding of an algorithm which takes as input the vectorized points from GIS and associates them with the heights transformed into z coordinates. The result is a three-dimensional grid of points. This grid is the basis for the creation of a single NURBS surface that will become the basis for the projection of all vector entities exported from the GIS into the modeler. In doing so, the result of the operation is a three-dimensional georeferenced NURBS model that contains all the vector entities in the territorial database.

An Improvement on the Upper Bounds of the Partial Derivatives of NURBS Surfaces

The Non-Uniform Rational B-spline (NURBS) surface not only has the characteristics of the rational Bézier surface, but also has changeable knot vectors and weights, which can express the quadric surface accurately. In this paper, we investigated new bounds of the first- and second-order partial derivatives of NURBS surfaces. A pilot study was performed using inequality theorems and degree reduction of B-spline basis functions. Theoretical analysis provides simple forms of the new bounds. Numerical examples are performed to illustrate that our method has sharper bounds than the existing ones.

A NURBS-optimized dRRM solution in a mono-channel condition for IEEE 802.11 entreprise Wlan networks

Dynamic radio resource management, RRM, is an essential design block in the functional architecture of any Wifi controller in IEEE 802.11 indoor dense enterprise Wlans. In a mono-channel condition, it helps tackle co-channel interference problem and enrich end-to-end Wifi clients experience. In this work, we present our dRRM solution: WLCx, and demonstrate its performance over related-work and vendor approaches. Our solution is built on a novel and realistic per-Beam coverage representation approach. Unlike the other RRM solutions, WLCx is dynamic: even the calculation system parameters are processed. This processing comes at price in terms of processing time. To overcome this limitation, we constructed and implemented a NURBS surface-based optimization to our RRM solution. Our NURBS optimized WLCx, N-WLCx, solution achieves almost 92.58% time reduction in comparison with basic WLCx. Furthermore, our optimization could easily be extended to enhance others, vendors and research, RRM solutions.