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30 April 2010, Volume 31 Issue 2 Previous Issue    Next Issue

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The Study of Knowledge Base of Machine Product Based on Ontology TAI Li-jun, ZHAO Han, DONG Yu-de, WU Zhao-yun 2010, 31(2): 1-8.  Abstract ( 185 )   PDF (723KB) ( 184 )   In order to solve the problem of knowledge management and knowledge reuse in the whole lifecycle of products development, a kind of framework of knowledge base of machine product based on ontology is put forward. The similarity is accounted in the four respects of syntax, attribute, structure and instance. So the process of mapping source ontology to object ontology is realized. The product knowledge model is built by using the ontology express language OWL (Web Ontology Language) and the method of case-based reasoning based on ontology is deeply studied too. At last, these methods are applied in the machine products knowledge base subsystem, which belongs to the knowledge management system of manufacturing. Related Articles | Metrics

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Mechanical Multi-Object Optimization Design Based on Fuzzy Theory WEI Feng-tao, SONG Li, LI Yan, SHI Kun, ZHAO Jian-feng 2010, 31(2): 9-12.  Abstract ( 149 )   PDF (457KB) ( 355 )   It is difficult to solve multi-objective optimization for inconsistency and incomparability among each single object. Multi-objective mathematical model of worm transmission is established. Effective solutions are obtained by general optimal arithmetic, such as improved genetic algorithm. The optimal solution is chosen from these available effective solutions and then ranked by the similarity priority ratio method of fuzzy theory. Related Articles | Metrics

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Research on Modeling Method for the Indexing Mechanism with Globoidal Cam FANG Dai-zheng, WANG Gui-cheng 2010, 31(2): 13-17.  Abstract ( 149 )   PDF (527KB) ( 217 )   After deeply studying the working principle of new type of indexing mechanism with globoidal cam, the equations of the contour surface and the conjugate contact line are established using D-H coordinate system. Taking full advantage of the roll’s geometry character, the track of centre line is drawn, and then the 3D model of globoidal cam is built using Pro/E software quickly. Thus the foundation is established to implement the numerical control machining, to carry through dynamics analyze and motion simulation and so on. Related Articles | Metrics

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Development of Tube-in-Tube Chimney CAD System FAN Gao-jie, WANG Zi-ru 2010, 31(2): 18-25.  Abstract ( 103 )   PDF (615KB) ( 183 )   A chimney CAD system is introduced which is developed by ObjectARX technology under the environment of AutoCAD. The system consists of three modules, that are pre-processing module, calculation module and post-processing module. Thus the integration is realized for the structure design of tube-in-tube chimney, calculation of reinforcingsteel configuration and drafting of engineering drawings. The system has some features such as friendly interface, easy operation, correct design and quick drafting, etc. Related Articles | Metrics

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Automatic Drawing of Longitudinal Section for Railway Lines Based on VBA QIU Rong-mao, WANG Da-ming, ZHANG Tao, ZHANG De-ying 2010, 31(2): 26-32.  Abstract ( 179 )   PDF (536KB) ( 312 )   The customization of AutoCAD with VBA is performed upon the data analysis of railway longitudinal section, and an auto-drawing system for this kind of drawings is realized. Firstly, the data related to the longitudinal section are organized to several Excel lists; then, the communication between AutoCAD and Excel is built; finally, the access of Excel lists is realized according to Excel-VBA mode. Related Articles | Metrics

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Parsing 3DXML File Format and Its Application WANG Xiao-bin, NING Tao, WANG Ke 2010, 31(2): 33-37.  Abstract ( 251 )   PDF (556KB) ( 533 )   3DXML file format is an important lightweight CAD data format. Through analyzing 3DXML file format, an approach to parse 3DXML file with MSXML is presented, which can be used to get important information from 3DXML file quickly. According to reconstructing the geometry and attribute information, the whole scene of assembly will be built. Using the LOD models, the speed of rendering will be accelerated. Finally, a lightweight CAD model viewer based on 3DXML file format is given as an example. Related Articles | Metrics

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A Method to Solve Constraint Conflict Based on the Minimal Conflict Sets LIU Xiao-ping, JI Hao, SHI Hui 2010, 31(2): 38-42.  Abstract ( 119 )   PDF (511KB) ( 205 )   In order to establish the human-cored conflict resolution methods in collaborative design，extracting the minimal conflict set is effective method for designer. Based on the analysis of the minimal conflict sets’ features and the intersecting-side algorithm, a method for extracting the minimal conflict set is presented. The example shows that the minimal conflict set can solve constraint conflict effectively under the designer participation. Related Articles | Metrics

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Evaluation of Roundness Error Based on RMGA MIAO Li-dong, GUO Hui, ZHANG Fan 2010, 31(2): 43-48.  Abstract ( 131 )   PDF (500KB) ( 226 )   In order to improve the problems of real-coding based genetic algorithm (RGA), such as premature convergence, rough result and low speed of calculation, the model structure of multi-population genetic algorithm (RMGA) is analyzed, and the parallel characteristics of this algorithm is applied to the roundness error evaluation. Experiments show that this algorithm can improve the accuracy and convergence in assessment of roundness error effectively. Related Articles | Metrics

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A Method to Generate the Minimum Bounding Boxes for Shape-Arbitrary Objects CHEN Hua 2010, 31(2): 49-53.  Abstract ( 184 )   PDF (455KB) ( 813 )   The concept of bounding box is wildly used in collision detection, section design of molds, packaging design of products as well as image processing and pattern recognition. Based on the different requirements in applications, a simple and practical method is presented to generate the minimum bounding boxes for shape-arbitrary objects. By using the function to determine the Axis-Aligned Bounding Boxes (AABB) in existing CAD software, a program is written based on the secondary development of AutoCAD. As a results, the minimum bounding boxes for shape-arbitrary objects can be generated to meet the requirements for different applications. Related Articles | Metrics

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Research on Architecture for Digital Campus LBS Based on Grid GIS REN Wei-zheng, DENG Zhong-liang, XU Lian-ming 2010, 31(2): 54-58.  Abstract ( 146 )   PDF (529KB) ( 240 )   The data organization and access mechanism model of the spatial information grid is developed for solving the spatial information share problem. The architecture of campus LBS based on grid geographical information system (CLGG) is proposed for services sharing, which composed of location tier, data tier, service tier and application tier. In the end, a prototype system is designed realizing district navigation and real time location and hot district information release et al. These functions of the prototype validate the feasibility and validity of the mechanism of the system. Related Articles | Metrics

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Application of Weight Particle Swarm Algorithm in Model Registration LIU Jing, LIN Da-jun 2010, 31(2): 59-62.  Abstract ( 147 )   PDF (364KB) ( 164 )   Particle swarm algorithm is widely applied in many fields. According to weight convergence range, weight function is established and it is applied to the process of velocity evolvement. In the evolvement process, sub-swarms are adopted. So the algorithm has good global convergence ability in the initial iterative stage and has good local convergence ability in the retral iterative stage. This can realize the balance between global search and local search. Weight particle swarm algorithm is used in registration for scattered point cloud and three dimensional CAD model. It has good registration result and fast convergence when it is compared with the basic particle swarm algorithm. Related Articles | Metrics

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A Fast Algorithm of Generating Stereogram Based on Dimension Reduction and Screening LIU Xiao-ping, XI Ya-si 2010, 31(2): 63-67.  Abstract ( 147 )   It is a key problem to raise generation speed in intersection-test-based autostereogram generation process. Firstly, spatial triangles and spatial lines are mapped into planar bounding boxes and two dimensional points, thus reducing dimensions; then a few possible intersecting triangles are screened out of all the triangles of the model according to the coordinates of the present scanning point, and finally intersection test is made with the small amount of screened out triangles. This method has been applied in the generation of stereogram and the generating speed has been remarkably increased without any degradation of the stereogram. Related Articles | Metrics

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Characteristic Building Modeling Based on Object-Oriented Template LIU Xiao-ping, QIAN Jing-jing, YU Ye, LUO Yue-tong 2010, 31(2): 68-72.  Abstract ( 95 )   PDF (479KB) ( 259 )   A modeling method of characteristic building based on object-oriented template is proposed through analyzing architecture construction characteristics. The template is formed on the basis of analyzing architecture construction rules in the view of architectonics, which are in comparison with O-O thought and then a framework composed of “Base Template”, “Structure Template” and “Instantiation Template” is proposed. The method can achieve the rapid construction and high-realistic rendering effect of 3D models of characteristic buildings, which is validated in the application of a tower modeling as an example. Related Articles | Metrics

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B-Spline Curve Reconstruction from Planar Unorganized Points Based on Field Distribution HUANG Tong-xin, WANG Wen-ke, ZHANG Hui, SONG Zheng-xuan 2010, 31(2): 73-83.  Abstract ( 161 )   PDF (641KB) ( 184 )   Curve reconstruction from planar unorganized points is one of the most important problems in reverse engineering. A practical B-spline curve fitting algorithm based on Goshtasby’s approach is presented. The digital image representing field distribution by estimating the bound of field strength basis function is generated at first, and then an algorithm of image thinning associated with improved BFS is proposed to overcome difficulties of obtaining the ridge contour under the situation of redundant branch pixels, and finally the weighted least squares method is used to extend the reconstructed curve for overcoming the deficiency that reconstructed curve may be shortened. Experiments show that the algorithm is valid and practical for B-spline curve reconstruction, especially when the given points are dense and noisy. Related Articles | Metrics

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Fast Implicit Surface Reconstruction for Densely Sampled Point Model MIAO Lan-fang, ZHOU Ting-fang, PENG Qun-sheng 2010, 31(2): 84-91.  Abstract ( 123 )   PDF (807KB) ( 335 )   The proposed algorithm uses the local bilateral filter function near the surface of the point model as the surface reconstruction function. The function value at a given position near the model surface can be computed directly by the bilateral filter function of the nearest K-neighbors. Compared with previous methods, this algorithm doesn’t need solve any linear system or non-linear equations and doesn’t need any internal or external support points. In addition, it can handle the noising data and preserve sharp features, since the function is based on a bilateral filter. Experiment results show that it can reconstruct high quality surfaces for complex 3D objects. Related Articles | Metrics

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A New Approach of Adaptive Compression and Mesh Generation for  Large Scale Scattered Data WANG Xiao-ming, LIU Ji-xiao 2010, 31(2): 92-96.  Abstract ( 117 )   PDF (863KB) ( 186 )   A triangular mesh sampling method based on the curvature and distance is proposed for the large scale scattered data. By this approach, the large scale scattered data can be compressed to a reasonable expected scale, and the triangular mesh generated by the compressed data can clearly describe the details of surface features. Every triangle patch of the generated mesh also has good shape. The experiments show that the method is efficient and easy to apply. Related Articles | Metrics

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C1-Continuous H-Type Coons Patches on Triangles TANG Yun-mei, WU Xiao-qin, HAN Xu-li 2010, 31(2): 97-103.  Abstract ( 115 )   PDF (744KB) ( 267 )   Two kinds of H-Coons patches with C1-continuity are constructed by two classes of H-Hermite polynomial functions on triangles. Triangular H-Coons patches present extensions of the Side-Side method and Side-Vertex method. These shapes depend on shape parameter and the limiting case for  0are the triangular Coons patches. Changing the value of , the interior shape of the patches can be adjusted, but it don’t influence the boundary shape of the patches. The examples show that this method for constructing surface is effective. Related Articles | Metrics

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Retinex Algorithm for Image Enhancement Based on Bilateral Filtering HU Wei-wei, WANG Rong-gui, FANG Shuai, HU Qiong 2010, 31(2): 104-109.  Abstract ( 358 )   PDF (686KB) ( 783 )   A Retinex algorithm based on bilateral filtering is proposed to the question of the apparition of halo artifacts in the presence of high contrast edges using exiting Retinex image enhancement. Firstly, this algorithm decomposes the original image into the illuminant image and the reflectance image using the bilateral filter which has the function of edge-preserving, then different strategies are used to compress the illuminant image and to enhance the reflectance image. At last, it composes the two part images to a new image. The algorithm can be verified from subjective visual effects and objective image quality assessment. The experimental results show that it has good enhancement result and can avoid halo artifacts. Related Articles | Metrics

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Image Retrieval Algorithm Based on the Color Feature of  Inner and Outer Edge ZHENG Qiu-mei, WANG Hong-xia, MIN Li-tian 2010, 31(2): 110-115.  Abstract ( 130 )   PDF (608KB) ( 212 )   The basic idea of the algorithm is to extract the color feature of edge area for image retrieval. The edges are divided into inner edge and outer edge and the weight of inner edge (target part) is increased. This is realized through the method of mathematical morphology with multi-scale and multi-structuring elements. By setting a weight for inner and outer edge, the algorithm takes the important of the target into account and overcomes the shortcoming of color histogram which loses the location information．Experimental results show that this method improves the image retrieval performance effectively. Related Articles | Metrics

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Robust Perceptual Hashing Algorithm to Geometric Distortions Based on Image Normalization SUN Rui, YAN Xiao-xing, DING Zhi-zhong 2010, 31(2): 116-122.  Abstract ( 152 )   PDF (666KB) ( 271 )   Image hashing functions have extensive applications in content authentication, database search and watermarking, etc. A novel perceptual hashing algorithm is developed which is robust to geometric distortions. The algorithm includes three stages: the first stage obtains the image that is invariant to any affine transforms through a normalization procedure; the second stage applies discrete wavelet transform to pseudo-randomly select sub-images to obtain secondary image including main features; the third stage uses singular value decomposing to capture local perceptual features and to get the final hash. The experiments show the method withstands perceptually preserved manipulations including geometric distortions, compression, and common signal processing operations. The content changes are also can be detected accurately. Thus the proposed method achieves perceptual robustness while avoiding misclassification. Related Articles | Metrics

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Interactive Image Segmentation Method Based on Fuzzy C-Means and Graph Cuts TIAN Yuan, WANG Cheng, GUAN Tao 2010, 31(2): 123-127.  Abstract ( 138 )   PDF (495KB) ( 342 )   In order to improve the segmentation performance when the foreground and the background are similar, an interactive image segmentation method based on fuzzy C-means and graph cuts algorithm is proposed. Firstly, the image is pre-segmented into a large number of small partitions using watershed algorithm which will be used instead of image pixels. Then, cluster centers of the foreground and background are calculated by the fuzzy C-means method. Finally, the likelihood energy is determined by the minimum distances from the unlabelled node to the foreground and background clusters, and the prior energy is determined by the relationship between the unlabelled node and its neighbor areas. The maximum-flow/minimum-cut algorithm is used to solve the global optimization problem. Compared with the results of other method, the experimental results show that our method can obtain a better segmentation performance with easy user interaction even though the foreground and background are similar. Related Articles | Metrics

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A Color Image Watermarking Algorithm Based on Multi-Wavelet Transform and Block-SVD HAN Shao-cheng, LUO Chang-jie, ZHANG Zhao-ning, WANG Yu-song 2010, 31(2): 128-133.  Abstract ( 148 )   PDF (742KB) ( 313 )   A non-blind watermarking algorithm is proposed based on multi-wavelet transform and block singular value decomposition. Choosing the saturation component of a color image as the watermark embedding domain, the watermark is a meaningful grayscale image. After Arnold scrambling, watermark is embedded into the different mid-frequency regions of the saturation component which through multi-wavelet transform. The examples demonstrate that the algorithm not only has good robustness to the noise, JPEG compression, shear and Photoshop processing , but also can resist to some geometric attacks such as rotation, scale and translation. Related Articles | Metrics

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Computer Simulation of Multi-Color Effect in Chinese Painting DENG Xue-xiong, ZHANG Wen, ZHANG Zhi-yao, YAN Wei 2010, 31(2): 134-138.  Abstract ( 135 )   PDF (515KB) ( 202 )   Multi-color effect in Chinese Painting has a special feature of color distribution in stroke which would be varied by the speed and power of using brush and couldn’t be solved by the existing method of Texture Mapping. To simulate its complex color gradation, the method of multi-color stroke by superposition of general strokes of different colors is presented. Some problems are discussed, such as the number calculation of general strokes in a multi-color stroke, the real time display and integer deleting of the multi-color stroke. This method avoids the complex process of calculating the color in the stroke area point by point and ensures the best color resolution in the multi-color stroke. The simulated results indicate that the rendering effect is very lifelike, not only keeping the power characteristics of original drawing, but solving the problem of color transition in strokes correctly. Related Articles | Metrics

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Dynamic Imitation of Moving Bridge Building Machine Based on VRML FENG Gui-zhen, WANG Da-ming, CHI Jian-bin, WANG Yong-mei 2010, 31(2): 139-143.  Abstract ( 135 )   PDF (430KB) ( 257 )   Bridge building machine is an important mechanic equipment. Due to its complicated structure, long product period and large investment, dynamic imitation is very important in the design. Aiming at the moving form frame bridge building machine, through studying its assembly structure and manufacturing process, a dynamical imitation system for this machine design is developed based on VRML with the characteristics of dynamic, interactive and low web brand network. Related Articles | Metrics

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The Visualization Research of Parabolic Gradient LIU Xiao-yang, LIN Da-jun, ZHENG Peng-fei, WU Zhi-ting 2010, 31(2): 144-149.  Abstract ( 145 )   PDF (424KB) ( 281 )   The changing trends of temperature and pressure can be considered as the process of gradient solution during the research of optimization of scalar field. Generally scalar field mathematical model can be considered as curved surface equation. In this paper the research of parabolic gradient is done by the graphic method. Mathematical expression is constructed, then the parabolic gradient is shown by Visual Lisp in AutoCAD. Related Articles | Metrics

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Rapid Calculation of Intersection Points between NURBS Surface and Line in Reverse Engineering WANG Bao-qing, ZHANG Li, LI Dong-sheng 2010, 31(2): 149-152.  Abstract ( 160 )   PDF (461KB) ( 292 )   Krawczyk operator is used to judge whether there are intersection points of a line with NURBS surface and the number of intersection points. Then the intersection points are solved by quasi-Newton method. The method is applied to verify the accuracy of free form reconstruction from point cloud data. Related Articles | Metrics

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A Superficial Analysis about Engineering Graphics Thinking MAO Xin, HUANG Ying, NA Lü-hong, LIU Yang 2010, 31(2): 153-159.  Abstract ( 122 )   PDF (419KB) ( 252 )   The thinking characteristics of image-building, stringency, engineering-ability and creativity in engineering graphics are put forward. Based on thinking psychology and thinking methodology, combining the teaching experience, the general process and main methods of imaginalthinking and image memory method are discussed. Also, the dialectical thinking method is discussed to promote the teaching level in depth. Lastly, the intelligence characters of engineering graphics thinking are put forward and analyzed, and the way of cultivating the ability of imaginalthinking in teaching is introduced. Related Articles | Metrics

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Study on the Programmable Innovation Design for Mechanical Drawing Course DU Zhen-hua, CHEN Guo-min, FENG Jian, QIN Yu-fang, TANG Yong-yong 2010, 31(2): 160-166.  Abstract ( 131 )   PDF (646KB) ( 238 )   Based on the study of thinking mode, the legitimacy thinking mode is put forward in teaching of mechanical drawing course. Through comparison with current thinking mode, the problem of too emphasizing the image thinking and too neglecting the logical thinking is found out. Taking the reading method of combination solids as example, the programmable innovation design for this content are designed to strengthen the logical thinking. The teaching practice shows that the former state “can understand but can not be used” is changed and this new teaching method is welcomed by the students. Related Articles | Metrics

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Research and Practice of the Methodology in Education for Engineering Drawing – A Method of Conducting Pratical Project in Educational Phases HU Lin 2010, 31(2): 167-173.  Abstract ( 173 )   PDF (610KB) ( 297 )   The criteria of an advanced-educated person in present day are claimed to gain multiple abilities and skills, which highly demands better quality on educational methodologies. Therefore, it is crucial to reform traditional educational patterns, to develop more efficient and more practical methods to enhance student’s abilities such as practical skills, innovative mentality and creativity. Thus, a novel method of conducting practical project in educational phases is introduced, which is featured with two aspects: ① Implementation of independent ideas for student to develop practical skills and creativities; ② To establish a team group of project to promot student’s integrated abilities. Related Articles | Metrics

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Virtual Dragoman Technology and Its Application Based on Computer Animation LUO Yue-tong, SUN Jing, CHU Zhao-hui 2010, 31(2): 174-177.  Abstract ( 133 )   PDF (381KB) ( 203 )   Virtual tourism based on virtual reality is blooming now, and just like dragoman is very important for tourism, virtual dragoman is also become very important for virtual tourism. Based on human modeling and computer animation, a virtual dragoman system, which make virtual tourism more interesting and realistic, is realized. Several key technologies are discussed and applied to the virtual tourism system with satisfied results. Related Articles | Metrics

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A View―Dependent Algorithm of Complex Model Simplification YANG Guan-liang, WANG Fang 2010, 31(2): 178-181.  Abstract ( 107 )   PDF (450KB) ( 271 )   In order to conquer the shortcoming of big calculation and slow speed of the Hoppe’s Edge Collapse Arithmetic, the simplified model is achieved by combining the Edge Collapse with the view-dependent gene. The improved data structure is used to dynamically generate multi-arrangement LOD model. The experimental results show that this arithmetic can not only preserve the important features of the model but also realize the model’s simplification. Related Articles | Metrics

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Research on Design Method for Twinbridge Steering Arm Mechanism LIU Ji-yu, LIU Gang, WANG Ze-dong 2010, 31(2): 182-187.  Abstract ( 162 )   PDF (612KB) ( 244 )   In order to carry out computer-aided design for the space steering arm mechanism, to make a computer program, which can reflect the relationship between parameters and deflexion angle of the steering arm mechanism, is necessary. Firstly, the space steering arm mechanism should be reduced to the plane mechanism and the analytical design method should be researched. Then the calculation can be implemented to the transformation error and angle deviation of steering wheel. The calculation results show that the error is no more than permissible value. Related Articles | Metrics

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Evaluating Algorithm of Roundness Error Based on Polar-Coordinate Measuring LEI Xian-qing, LI Ji-shun, XUE Yu-jun, CHANG Wei-hang 2010, 31(2): 188-191.  Abstract ( 155 )   PDF (431KB) ( 191 )   A new kind of method of evaluating roundness error using polar measurement data, which named as mesh searching algorithm, is presented. The principle of the algorithm is that series of polar-coordinate mesh points are collocated around the periphery of the least square circle according to certain rule, the radius value of all the measured points are calculated by regarding each mesh point as the ideal center, the roundness error value of minimum circumscribed method, maximum inscribed method and minimum zone method are achieved accurately through comparing these radius value. The process and step of using the algorithm are described in detail and the mathematical formula and program flowchart are given. The results of the experiment show that the roundness error can be evaluated effectually and accurately. Related Articles | Metrics

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Control Method of Motion Track and Torch Posture for Multi-Pipe Intersection Curve Cutting CAO Jian-fu, ZHANG Heng-chao 2010, 31(2): 192-197.  Abstract ( 132 )   PDF (469KB) ( 205 )   While dealing with cutting of multi-pipe intersection curve, a practical algorithm of motion track and torch posture is proposed based on a predigesting slope model. Computational models of intersection curve are given with parametric 3D mode, and the conversion method is constructed from 3D model data to 6 axis numerical code. The cutting experiment shows the effectiveness of this method. Related Articles | Metrics

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Modeling and Simulation for Intersection Line Cutting Curves Based on OpenGL ZHAO Long, GUO Yan-ling 2010, 31(2): 198-203.  Abstract ( 112 )   PDF (569KB) ( 234 )   The application conditions and characteristics are analyzed to invariable and variable groove angle. According to analytic geometry and linear algebra, a general mathematical model for pipe intersections is established, and a specific algorithm to determine the groove angle for NC cutting is proposed so as to provide a reliable data source for the implementation of the simulation for intersection curve cutting. A simulation program is written by VC++ and OpenGL, and the simulation for the cutting curve with variable groove angle is implemented. The results indicate that the main pipe and the branch pipe could be assembled precisely and the welding groove exactly corresponding to the API specification. Related Articles | Metrics