Three-Dimensional Geometrical Modelling of Wild Boar Head by Reverse Engineering Technology

In this paper, a wild boar head was taken as the bionic research object for the development of new ridgers, a kind of plough. The reverse engineering technology was adopted to obtain the surface geometrical information of the head. Several three-dimensional （3D） point clouds of the head were captured first using a non-touch laser scanner, and an integrated point cloud was generated by aligning these point clouds using UG/Imageware. Then, the digital surface model of the head was rebuilt by means of CATIA. The characteristic curves of the surface model were analyzed. The results show that the average error between the rebuilt surface and the point cloud is -0.431 ram. The max curvature of the ridge on the neb of the head is 0.187 mm^-1, and the max and rain Gauss curvatures on the surface are 0.008 mm^-2 and -0.002 mm^-2. These geometrical information are the essential parameters for biomimetics study of the ridger.

Reverse Engineering, Some Board Games as a Key to the Development of Artificial Intelligence and Construction of Economic Models

Reverse engineering, also called back engineering, is the process of extracting knowledge or designing information from anything： mechanical device electronic components, computer programs, or biological, chemical matters, and--subsequently--analyzing its components. Reverse engineering can be applied for the sake of creating artificial intelligence, e.g. when the used methods are based on very old games, such as Go and chess. Many generations of computers are able to play at the same level as human grandmasters. A computers＇ arrival at that level is due to imitation of human Go or chess play. A particular emphasis shall be placed upon the Go game, known for 5,500 years. Invented in China, it may be classified as the oldest board game, having its ardent enthusiasts until present times. Old physical issues can be easily projected upon the modeling of new economic phenomena and quantum games. The aim of this paper is to discuss the applications of reverse engineering, traditional social games and other domains, such as quantum physics, to the analysis of utterly new social as well as economic phenomena.

Application Study on 3D Modeling of Axial Compressor Blades Based on CFD and CAD

A new method for design of turbomachinery blades is presented. The parameters of a compressor blade are created from the Computational Fluid Dynamics （CFD） software CFX-BladeGen, and are inputted to the Computer Aided Design （CAD） software UG for building a curve surface model to create an entity model in UG. The result shows that the blade model is favorable from the entity effect and reflection analysis and the model process is useful for the CAD model creation of turbomachinery blades.

Study of 3D Mannequin and Garment Modeling in Garment CAD

On the base of studying the modeling technique of man-nequin and garment curved surface with non-uniform rational B-spline(NURBS),several methods of mannequin data pickup on 2D screen are proposed.A garment style creating method,which gets the key points for garment style modeling by drawing panel contour aroundthe mannequin on the screen and calculating the offset value between the body and the garment,is presented.Then 3D garment styles can be easily modeled with the key points and interactively modified.

REVERSE MODELING FOR CONIC BLENDING FEATURE

A novel method to extract conic blending feature in reverse engineering is presented. Different from the methods to recover constant and variable radius blends from unorganized points, it contains not only novel segmentation and feature recognition techniques, but also bias corrected technique to capture more reliable distribution of feature parameters along the spine curve. The segmentation depending on point classification separates the points in the conic blend region from the input point cloud. The available feature parameters of the cross-sectional curves are extracted with the processes of slicing point clouds with planes, conic curve fitting, and parameters estimation and compensation, The extracted parameters and its distribution laws are refined according to statistic theory such as regression analysis and hypothesis test. The proposed method can accurately capture the original design intentions and conveniently guide the reverse modeling process. Application examples are presented to verify the high precision and stability of the proposed method.

Applications of Computer Aided Modeling Techniques to Complex ICE Components

Design of internal combustion engine (ICE) components is one of the earliest and also the most active areas in which computer aided modeling techniques are applied. Computer aided modeling techniques could provide requisite information for follow up designing segments such as structural analysis, design of technological process and manufacturing etc, and thereby lead to the reduction of product design period and the quality and reliability improvement of ICE components. So the developing situations of ICE components' 2 D drafting, 3 D modeling of ICE, overall CAD of ICE as well as component design expert system etc. are surveyed, which are the typical applications of computer aided modeling techniques in ICE component design process, and some existent problems and tasks are pointed out so as to make some references for the further research work.

Surfacer在模具CAD/CAM反求造型中的应用研究

本文就涡轮反求造型的实例, 采用Surfacer软件规划出由实物转化为工程 CAD资料的一般流程。在深入分析点云数据的矢量方向基础上, 采用积累弦长参数化方案实现点云的参数化; 根据最小二乘法曲线拟合原理, 修改曲线参数获得高品质曲线; 并重点论述了点云处理、曲线生成、建构曲面的方法, 为模具加工提供了建构高品质CAD模型的有效途径。

Science Letters:Mask synthesis and verification based on geometric model for surface micro-machined MEMS

Traditional MEMS （microelectromechanical system） design methodology is not a structured method and has become an obstacle for MEMS creative design. In this paper, a novel method of mask synthesis and verification for surface micro-machined MEMS is proposed, which is based on the geometric model of a MEMS device. The emphasis is focused on synthesizing the masks at the basis of the layer model generated from the geometric model of the MEMS device. The method is comprised of several steps： the correction of the layer model, the generation of initial masks and final masks including multi-layer etch masks, and mask simulation. Finally some test resuhs are given.

Aspect-oriented software reverse engineering

To solve the identification and comprehension problem of crosscutting concerns in existing legacy software system, a framework of aspect-oriented software reveme engineering is proposed. An approach on re-modularizing traversal features of legacy system is presented based on various unified modeling language （UML） diagrams. While modeling crosscutting concerns in UML use case diagrams, the non-functional requirements that affect several use case modules can be enveloped into aspect modules with a stereotype mechanism. The recurring message transmission patterns can be re-modularized as aspects in UML sequence diagrams with UML collaborations. Standard UML activity diagram notations are extended and modified by node fusion and addition, which support the graphical composition operation between crosscutting behaviors and primary business roles of concurrent systems. Case study indicates that travernal features of software system can be extracted and re-modularized from various perspectives in aspect-oriented reverse engineering, which improves comprehensibility and maintainability of legacy systems.

Reverse Engineering Based Methodology for Redesigning Contour Milling Tools

Reverse Engineering (RE) involves the use of techniques aimed to retrieve information about manufactured products, not only regarding geometries, but also materials and functionality. Today, even if several RE techniques are known, many of them still leave the object unusable to analyze. Nevertheless, other alternatives to this problem allows for obtaining a Digital or Virtual Model (VM) via the three-dimen- sional scanning. Getting the VM of an item, via scanning or not, can offer many possibilities to digital analysis (FEM). Furthermore, starting from VM, it is possible to achieve the physical reproduction of an element, part or workpiece—in the same or different materials—using Additive Manufacturing (AM) technologies. This enables to improve the product through a redesign process. In this paper, a RE based methodology is proposed for redesigning a tool for contour milling, after comparing different microscopy based techniques, 3D-Scanner tools and CAD-CAGD utilities for generating a Virtual Model of the newly designed mill.

A TECHNIQUE OF DIGITAL SURFACE MODEL GENERATION

It is usually a time-consuming process to real-time set up 3D digital surface model(DSM) of an object with complex surface.On the basis of the architectural survey project of"Chilin Nunnery Reconstruction",this paper investigates an easy and feasible way,that is,on project site,applying digital close range photogrammetry and CAD technique to establish the DSM for simulating ancient architectures with complex surface.The method has been proved very effective in practice.

Study on the Digital Manufacturing System of Ship Model Surface

Because a ship model surface (SMS) is a large double-curved 3-D surface,the machining efficiency of the cur- rent handcraft manufacturing method are very low,and the precision is difficult to control also.In order to greatly improve the machining efficiency and precision of SMS,based on the CAD/CAM/CNC technology,this paper proposed a model of SMS digi- tal manufacturing system,which is composed of five functional modules (preprocess module,CAD module,CAM module,post- process module and CNC module),and a twin-skeg SMS as an example,the key technologies & design principle of the nodtules were investigated also Based on the above research works,the first set of 4-axis SMS Digital Manufacturing System in China has been successfully developed,which can reduce the machining time of the twin-skeg SMS from 30 working days needed for the cur- rent handcrafting manufacturing method to 8 hours now,and which can control more effectively the precision of SMS also.

PHYSICS-BASED ILLUMINATION MODEL FOR METAL SURFACE RECONSTRUCTION IN RE

Representation of roughness is introduced and the rationality of applying thephysics-based model in RE is analyzed at first. Then the scattering theory of electromagnetic waveis simplified and deduced to a physics-based model according to the characteristics of the surfaceto be reconstructed in RE. At last, the intensity diagrams of reflected field distribution areprovided to prove the feasibility of the presented model and some spheres are rendered with thismodel.

Reconstruction of symmetric models composed of analytic curves and surfaces from point cloud

This paper presents a method to reconstruct symmetric geometric models from point cloud with inherent symmetric structure. Symmetry types commonly found in engineering parts, i.e., translational, reflectional and rotational symmetries are considered. The reconstruction problem is formulated as a constrained optimization, where the objective function is the sum of squared distances of points to the model, and constraints are enforced to keep geometric relationships in the model. First, the explicit representations of symmetric models are presented. Then, by using the concept of parameterized points (where the coor-dinate components are represented as functions rather than constants), the distances of points to symmetric models are deduced. With these distance functions, symmetry information, for both 2D and 3D models, is uniformly represented in the process of reconstruction. The constrained optimization problem is solved by a standard nonlinear optimization method. Owing to the explicit representation of symmetry information, the computational complexity of our method is reduced greatly. Finally, examples are given to demonstrate the application of the proposed method.

Theoretical Study on Stochastic Modeling of Combined Gravity-Magnetic-Electric-Seismic Inversion and Its Application

As gravity field, magnetic field, electric field and seismic wave field are all physical fields, their object function, reverse function and compound function are certainly infinite continuously differentiable functions which can be expanded into Taylor (Fourier) series within domain of definition and be further reduced into solving stochastic distribution function of series and statistic inference of optimal approximation. This is the basis of combined gravity-magnetic-electric-seismic inversion of stochastic modeling. It is an uncertainty modeling technology of combining gravity-magnetic-electric-seismic inversion built on the basis of separation of field and source gravity-magnetic difference-value (D-value) trend surface, taking distribution-independent fault system as its unit, depths of seismic and electric interfaces of interests as its corresponding bivariate compound reverse function of gravity-magnetic anomalies and using high order polynomial (high order trigonometric function) approximating to its series distribution. The difference from current dominant inversion techniques is that, first, it does not respectively create gravity-seismic, magnetic-seismic deterministic inversion model from theoretical model, but combines gravity-magnetic-electric-seismic stochastic inversion model from stochastic model; second, after the concept of equivalent geological body being introduced, using feature of independent variable of gravity-magnetic field functions, taking density and susceptibility related to gravity-magnetic function as default parameters of model, the deterministic model is established owing to better solution to the contradiction of difficulty in identifying strata and less test analytical data for density and susceptibility in newly explored area; third, under assumption of independent parent distribution, a real modeling by strata, the problem of difficult plane closure arising in profile modeling is avoided. This technology has richer and more detailed fault and strata information than sparse pattern seismic data in newly explored area, successfully inverses and plots structural map of Indosinian discontinuity in Hefei basin with combined gravity-magnetic-electric-seismic inversion. With development of high precision gravity-magnetic and overall geophysical technology, it is certain for introducing new methods of stochastic modeling and computational intelligence and promoting the development of combined gravity-magnetic-electric-seismic inversion to open a new substantial path.

AN ENGINEERING MODEL FOR MULTICOMPONENT REVERSIBLE REACTION NETWORK

The treatment of a multicomponent reversible reaction network is extremely complicated because largenumber of rate constants must be precisely determined and because the calculation based on these rateconstants is tedious.In order to reduce the degrees of freedom of the process,the authors propose a methodin which the reactor and the separator are regarded as a whole.Based on this approach,an N-componentreversible reaction system can be dealt with as a two—component system.Consequently,a simple and ac-cessible way of the apparent rate determination is suggested.For fiist-order reactions,an explicit,simplifiedexpression has been derived for both lumped and distributed parameter reaction systems.

Conceptual modelling approach of mechanical products based on functional surface

A modelling framework based on functional surface is presented to support conceptual design of mechanical products. The framework organizes product information in an abstract and multilevel manner. It consists of two mapping processes： function decomposition process and form reconstitution process. The steady mapping relationship from function to form （function-functional surface-form） is realized by taking functional surface as the middle layer. It farthest reduces the possibilities of combinatorial explosion that can occur during function decomposition and form reconstitution. Finally, CAD tools are developed and an auto-bender machine is applied to demonstrate the proposed approach

Reverse Engineering Activity Diagrams from Object Oriented Code： An MDA-Based Approach

The success of system modernization depends on the existence of technical frameworks for information integration and tool interoperation like the Model Driven Architecture （MDA）. Reverse engineering techniques play a crucial role in system modernization. This paper describes how to reverse engineering activity diagrams from object oriented code in the MDA context focusing on transformations at model and metamodel levels. A framework to reverse engineering MDA models from object oriented code that distinguishes three different abstraction levels linked to models, metamodels and formal specifications, is described. At model level, transformations are based on static and dynamic analysis. At metamodel level, transformations are specified as 0CL （Object Constraint Language） contracts between M0F （Meta Object Facility） metamodels which control the consistency of these transformations. The level of formal specification includes algebraic specifications of MOF metamodels and metamodel-based transformations. This paper analyzes a recovery process of activity diagrams from Java code by applying static and dynamic analysis and shows a formalization of this process in terms of MOF metamodels. The authors validate their approach by using Eclipse Modeling Framework, Ecore metamodels and ATL （Atlas Transformation Language）.

Bridge Engineering-Oriented Parametric Model

A new model is proposed to improve the efficiency of structural modeling. In this model, the bridge structural components are expressed with component description, parametric description and geometric description in a software system. This model provides both convenience and flexibility for users in structural modeling process. The object-oriented method is applied in the model implementation. A bridge analysis preprocessor is developed on the basis of this model. It provides an effective way for bridge modeling.

基于实物的复杂曲面产品反求工程中的CAD建模技术

基于零件实物样件的几何模型的反求已成为ＣＡＤ／ＣＡＭ领域中的一个研究热点。对目前国内外在复杂曲面产品反求工程中ＣＡＤ建模方面的研究现状做一较为简要的归纳。