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30 June 2016, Volume 37 Issue 3 Previous Issue    Next Issue

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An Algorithm for Generating Patterns of Double-Rows and Multi Segments Li Hua, Cui Yaodong, Wang Yanxin 2016, 37(3): 285-289.  DOI: 10.11996/JG.j.2095-302X.2016030285 Abstract ( 63 )   PDF (236KB) ( 204 )   To solve large scale unconstrained two-dimensional guillotine-cutting problem of rectangular items, an algorithm for generating the patterns of double-rows and multi segments is proposed, where the plate is divided into two segments by a cut, each of which is then divided into a series of blocks with a set of cuts, and each block contains a group of horizontal strips. The optimal position of the cut that divides the plate into two segments is determined through enumeration. Knapsack problems are solved to obtain the maximum values of all possible blocks and the block layouts on the segments. The algorithm is tested on two groups of benchmark problems in the literature. The computational results indicate that the algorithm can obtain better optimization results in a reasonable computation time. Related Articles | Metrics

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Research on System of Facial Expression Capture and Animation Simulation#br# Based on Kinect He Qinzheng, Wang Yunqiao 2016, 37(3): 290-295.  DOI: 10.11996/JG.j.2095-302X.2016030290 Abstract ( 113 )   PDF (4905KB) ( 423 )   The technical of 3D human facial expression animation is a subject which has potential application and fatal research significance. This paper proposes a facial expression animation solution based on Microsoft Kinect device after the research of existing facial expression capture technology and animation synthesis technology. First, Kinect device is used to capture the face data and relevant expression parameters are extracted, at the same time, a three-dimensional model of face is reconstructed with Autodesk Maya animation software. Then the model is imported to OGRE animation engine and the expression parameters transferred to OGRE in which real time facial expression animation is rendered at last. Experiment results show that the method can provide an acceptable and reliable real-time facial expression animation. Compared to other existing facial expression animation technologies, the system is easier to operate with rather inexpensive device. Related Articles | Metrics

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A Distance-Based Edge-Bundling Method Yang Haobin, Zhou Hong 2016, 37(3): 296-301.  DOI: 10.11996/JG.j.2095-302X.2016030296 Abstract ( 78 )   PDF (429KB) ( 298 )   Edge bundling has become a research hotspot in the field of information visualization. The edge-bundling methods address the visual clutter problem caused by extensive edge crossings in graphs. Among the recent edge-bundling methods, the algorithms which are based on the path construction are generally efficient and have good bundling results, the algorithms which are based on edge clustering and the skeleton construction can effectively reveal underlying patterns. Based on these works, a distance-based edge-bundling method is presented, with the features of space distances and skeletons, which can improve the edge-bundling results generated by the skeleton-based edge-bundling method. The experiment results demonstrate that the distance-based method is efficient and effective in pattern revealing, so that this method can avoid the over bundling problem of the previous one. In summary, this method is a practical one that can simplify the computing process and avoid the singularity problem. Related Articles | Metrics

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Surface Tension Simulation for SPH Fluid Based on IIF Model Dong Lanfang, Zhang Heng, Chen Junxiong 2016, 37(3): 302-307.  DOI: 10.11996/JG.j.2095-302X.2016030302 Abstract ( 120 )   PDF (558KB) ( 297 )   Surface tension effect at fluid-air and fluid-solid interfaces should not be ignored when simulating fluid based on smoothed particle hydrodynamics (SPH) method, it affects the accuracy of the simulation and visual realism. The existing surface tension models such as the continuum surface force (CSF) model and the inter-particle interaction force (IIF) model both have their own flaws. This paper focus on the IIF model which can causes non-physical particle clustering and the irregular shape of fluid surface, and surface tension is modeled by an attraction-repulsion force which is formalized by a Lennard-Jones like potential function, and a SPH tension correction term which based on the normal difference between neighboring particles is introduced to minimize the surface area and smooth the surface. Experimental results show that the proposed method can simulate the surface tension effect accurately and stably. Related Articles | Metrics

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GIS-Based EIA Visualization of Elevated Road Traffic Noise Wu Peining, Zhou Baishun, Zhou Shuqiu 2016, 37(3): 308-315.  DOI: 10.11996/JG.j.2095-302X.2016030308 Abstract ( 74 )   PDF (541KB) ( 298 )   Focus on the visualization of GIS-based evaluation area traffic noise environmental impact assessment (EIA), the boundary lines generating algorithm followed on the centre line of the road is presented. A method for the Cartesian grids generation with sound area self-adaptive grids refinement algorithm is provided to the complex evaluation area for the unstructured grids generation. Based on the unstructured grids, the equivalent sound level EIA model for evaluation area is proposed and the visualization of the EIA calculation is achieved. Through the visualization and analysis of an elevated highway example, the accuracy and efficiency of the proposed methods are confirmed. Related Articles | Metrics

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Symmetry Based Broken Jaw Reconstruction Method and its Application Luo Yuetong, Xu Bingqing1 Xue Hao, Shi Fangfang, Zhang Wei, Ding Sheng 2016, 37(3): 316-321.  DOI: 10.11996/JG.j.2095-302X.2016030316 Abstract ( 64 )   PDF (1921KB) ( 249 )   For oral surgery of dislocated fracture jaw reconstruction, a broken jaw reconstruction method is presented to help doctors for preoperative planning and preparation. Firstly, marching cube algorithm is used to extract facet model from patient’s CT image data, then a sketch-based interactive segmentation method, which combines graph cut algorithm and SDF descriptor and Gaussian mixture models, is presented to allow doctors to segment broken jaw rapidly by simple strokes; at last reconstruction is realized automatically based on the craniofacial symmetry. This method accomplishes reconstruction by reposition of broken jaw so that it can fully keep important fracture information for doctors. The method has been applied in self-developed jaw reconstruction system; patient data from The First Affiliated Hospital of Anhui Medical University has been used for testing, the result demonstrates the effectiveness of this approach. Related Articles | Metrics

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A Gridding Hough Transform Based on Subtractive Clustering Liang Yongqiang, Zhao Jun, Meng Qiaoyuan 2016, 37(3): 322-328.  DOI: 10.11996/JG.j.2095-302X.2016030322 Abstract ( 78 )   PDF (2333KB) ( 245 )   To solve the problem of undetected-line and pseudo-line resulting from unsuitable manual voting parameter in gridding Hough transform, a non-voting-parameter gridding Hough ttansform based on subtractive clustering is proposed. Firstly a two-stage scan in monotonous way is adopted to make every linelet as long as possible, and then the subset of voting linelets is automatically determined by characteristics of the lack of long linelets and the abundance of short linelets. Finally a fault-tolerant voting process is realized by using subtractive clustering. Our experimental results show that the proposed algorithm has a fast execution speed, and without manual voting parameter, and is very good to avoid the problem of undetected-line and pseudo-line resulting from unsuitable manual voting parameter by combining it with subtractive clustering. Related Articles | Metrics

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The Extended Cubic Uniform B-Spline Curve Based on Totally Positive Basis Yan Lanlan, Han Xuli 2016, 37(3): 329-336.  DOI: 10.11996/JG.j.2095-302X.2016030329 Abstract ( 64 )   PDF (335KB) ( 189 )   This paper aims to construct a shape-preserving extended cubic uniform B-spline curve. Firstly, within the theoretical framework of quasi extended Chebyshev space, we prove that the existing extended basis of the cubic Bézier curve, λ-Bézier basis for short, is the normalized B-basis of the corresponding space. Then we use the linear combination of the λ-Bézier basis to express the extended basis of the cubic uniform B-spline curve. According to the preset properties of the curve, we deduce the properties of the extended basis, and then determine the coefficients of the linear combination. The extended basis can be represented as the product of the λ-Bézier basis and a conversion matrix. We prove the totally positive property of the matrix and the extended basis. By using this basis, we define a curve based on 3-point piecewise scheme and analyze its properties. The totally positive property makes the curve can simulate the shape of the control polygon. The surface based on 16-point piecewise scheme is briefly introduced. Related Articles | Metrics

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Sequential Value Correction Heuristic Algorithm for the Circle Cutting Stock Problem Hu Gang, Yang Rui, Pan Liwu 2016, 37(3): 337-341.  DOI: 10.11996/JG.j.2095-302X.2016030337 Abstract ( 76 )   PDF (429KB) ( 230 )   This paper discusses the problem of generating optimal cutting plan for circles. The cutting plan consists of several cutting patterns. First a knapsack algorithm that generating four-block cutting patterns of circle strips was constructed; then the sequential value correction heuristic algorithm was used to generate the cutting plan, it iteratively calls the above knapsack algorithm procedure improves the objective function based on the principle of minimum production cost and correct the current value of circles, generates a new pattern according to the current value; in the end a set of optimal cutting patterns was choose to form the cutting plan. The cutting stock algorithm was tested with the benchmark problems of literatures, and compared with the T-shape algorithm and heuristic algorithm. The results of numerical experiments show that, the material utilization rate of the algorithm is higher 0.83% and 3.63% than the above two algorithms. Related Articles | Metrics

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An Improved Method for Airfoil Parameterization by B-Spline Zhang Ji, Zhu Chungang, Feng Renzhong, Liu Mingming, Zhang Hengyang 2016, 37(3): 342-348.  DOI: 10.11996/JG.j.2095-302X.2016030342 Abstract ( 136 )   PDF (423KB) ( 374 )   Airfoil design is a crucial issue of aerodynamic research, the parameterization of airfoil will affect the airfoil optimization design. In order to reduce the number of variables in the airfoil optimization, eliminate the unfairness phenomenon, preserve the C2 continuity condition, and control the geometric characteristics of the airfoil in the optimization process, in this paper, we present an improved method for airfoil parameterization by B-spline. The method represents airfoil by a cubic non-uniform B-spline curve. Fitting of airfoil data by B-spline curve is mainly by least square method and the normal constraints. And the final result is obtained by iteration. Experiments show that the proposed method can be well fitted to the typical airfoil data, the resulting curve is fair and C2 continuity, and has few parameters of airfoil function compared with the classical airfoil parametric methods. Related Articles | Metrics

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Degeneracy Relations for Two Spatial Triangles Yu Haiyan, Yu Peiwen, Zhang Shuai, He Yuanjun 2016, 37(3): 349-354.  DOI: 10.11996/JG.j.2095-302X.2016030349 Abstract ( 81 )   PDF (295KB) ( 221 )   This paper discussed degeneracy and robustness issues in geometric computing by an example of two 3D triangle pairs intersecting ,especially the classification of their various relations. The first key to a problem is to describe this problem. Hence, the complete representation of degeneracies is an important foundation and support to design, improve as well as test a robust geometric computing algorithm. For the first time, this paper studies degeneracies for various triangle pairs in 3D space. Based on projecting reduction, their relationships are classified and a complete sample model is deduced to cover all kinds of degeneracies. The basic strategy is to establish a computed coordinate system. Then by projection, 3D relations are reduced to planar ones. Fixing one triangle, and changing the relative position and size of the other, various relations are classified in the clue of departed, contacted, intersected and overlapped. Consequently, all degeneracies can be got. The method proposed in this paper provides a new way to robustness 3D geometric computing algorithms not only for testing samples but also for algorithm reforming. Related Articles | Metrics

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Research on the Property of Attractive Factor in Three Dimensional Rectangular Packing Problems Wang Jinmin 2016, 37(3): 355-358.  DOI: 10.11996/JG.j.2095-302X.2016030355 Abstract ( 60 )   PDF (197KB) ( 180 )   The attractive factor approach, which is one of the quantitative positioning rules, has got satisfactory effects in solving three-dimensional packing problems. The paper studies the attractive factor approach and gets some properties as follows: best fit packing point, taxis to convex and corner point, uniqueness of invisible attractor factor and the “dynamic” of location. It will be conducive to enable the better usage of attractor factor approach in solving three-dimensional rectangular packing problems. Related Articles | Metrics

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A Data Reduction and Ordering Algorithm for Scattered and Layered Point Cloud Xie Zexiao, Liu Jingxiao, Pan Chengcheng, Zhang Mengze 2016, 37(3): 359-366.  DOI: 10.11996/JG.j.2095-302X.2016030359 Abstract ( 74 )   PDF (967KB) ( 350 )   Concerning the scattered and layered characteristic of point cloud acquired by laser scanners, a data reduction and ordering algorithm is proposed. Firstly the spatial index of point cloud is created based on known marked points using a method integrating Octree and 3D R-tree, ensuring fast and correct access to local data and high efficiency of data retrieval. Secondly one axis of the work coordinate system is selected as the projective direction for parameterizing the local data, which is determined by the normal vector of local reference plane. Then along the selected direction the local data is parameterized and the quadratic surface is approximated. Finally the ordered set of reference points is obtained by sampling the quadratic surface through the R-tree’s leaf nodes, making the scattered and layered point cloud be single layered. Application examples show that the algorithm can improve the overall accuracy of the data as well as maintain the details of point cloud, indicating good validity and practicability in the reduction of scattered and layered large-scale point cloud with complex geometric features. Related Articles | Metrics

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A Review of Computer Aided Design for Bone Tissue Scaffolds Yao Yazhou, Xie Jingsong, Fan Shuqian 2016, 37(3): 367-376.  DOI: 10.11996/JG.j.2095-302X.2016030367 Abstract ( 121 )   PDF (1588KB) ( 298 )   The new and emerging additive manufacturing technologies in recent years make it possible to fabricate bone tissue scaffolds with highly complex geometry structure. Based on the versatile functionality requirements, the structures of bone tissue scaffolds are firstly categorized into two groups, more precisely, the regular porous structure and the irregular ones, according to their geometries. Then the design methods for above classified structures are reviewed respectively. The triply periodic minimal surfaces (TPMS) based and topology optimization based design methods, which are very suitable for additive manufacturing, are especially emphasized. Finally, technical challenges for the design methods of bone tissue scaffolds are analyzed, and the possible developing trend in this field is prospected. Related Articles | Metrics

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Urban Road Network Modeling Based on Finite Element Mesh Generation Wang Yuan, Liu Hua, Li Hang 2016, 37(3): 377-385.  DOI: 10.11996/JG.j.2095-302X.2016030377 Abstract ( 185 )   PDF (5470KB) ( 398 )   Considering the functional region in urban, we present a road modeling method based on the algorithms of finite element mesh and road feathers in city district. In our method, urban planning theory is used to build hierarchical road and the trunk roads can be defined and extracted from the branch roads. This experiment combines the road level, land utilization, functional region and characteristic of the road in urban, and shows reasonable result compared to road networks in urban planning. Related Articles | Metrics

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A User-Defined Feature Based Technique for Intelligent Inspection Planning of Aircraft Structural Parts Zeng Debiao, Wan Shiming, Peng Jiangtao, Li Yingguang, Zheng Guolei 2016, 37(3): 386-393.  DOI: 10.11996/JG.j.2095-302X.2016030386 Abstract ( 96 )   PDF (862KB) ( 244 )   Form features of aircraft structural parts are usually inspected by coordinate measuring machines. In order to inspect complex form features of aircraft structural parts and extend the scope of form features which can be inspected, a neutral framework for form feature definition and a generic algorithm for feature recognition based on the framework were studied. Then an intelligent measuring point distribution algorithm driven by inspection knowledge was proposed. Finally an algorithm combining clustering and improved simulated annealing algorithm was designed for optimizing measuring orientations. Thus intelligent inspection planning based on user-defined feature and inspection knowledge was realized. This technique has been applied in the manufacturing process of several major aviation products, and significantly improved the efficiency and intelligent level of aircraft structural part inspection planning. Related Articles | Metrics

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Two Stepped Innovation Design Method of Products Based on the QFD Zhou Xiaojun, Yang Qin 2016, 37(3): 394-399.  DOI: 10.11996/JG.j.2095-302X.2016030394 Abstract ( 96 )   PDF (879KB) ( 261 )   The article presented two stepped innovative design method of products based on quality function deployment (QFD), through the analysis of user needs and the main factors affecting two innovative, in status of products should meeting the needs of users and having the application of innovation in the fierce market competition. The design method establish the model of product innovation design based on QFD and implement steps through exploring clients’ demand for target product, using QFD to analyzing customer’s needs and combining two innovative customer factors, and get obtain the appropriate technology and solutions. on this method the article verify practicability and Scientificity of the design methods by electric scooter design example. Related Articles | Metrics

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The Research and Application on CAD/CAM of the Chinese Character on Inclined Plane Liu Jikai, Zhao Qingzhi, Zhang Linhua, Zhang Xingwu, Wang Hongjia 2016, 37(3): 400-404.  DOI: 10.11996/JG.j.2095-302X.2016030400 Abstract ( 77 )   PDF (7450KB) ( 90 )   A method that vector characters are carved in the inclined plane is proposed in the paper. The processes of characters carved in the inclined plane include the process of characters carved in the horizontal plane according to the relevant papers, rotation matrix in the spatial coordinate and the 7th Bezier curve fitting on the basis of C3 continuous space. OpenGL can realize the arbitrary rotation, zoom and pan of graphics, enhancing the human-computer interaction. According to the experiments, we can find out the software interface is friendly and has good robustness in this method. NC code can be run stably on CNC machine to achieved the desired effect. That will improve the processing efficiency of characters carved in the inclined plane and reduce the processing errors. Related Articles | Metrics

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Research on Length Matching of Micro-Vehicle’s Shaft Pipe Based on Euler-Bernoulli Theory Huang Fengyun, Zhu Jianguo, Zhou Zihan, Shi Lei 2016, 37(3): 405-409.  DOI: 10.11996/JG.j.2095-302X.2016030405 Abstract ( 80 )   PDF (331KB) ( 222 )   Take one micro-vehicle’s transmission shaft as the research object, and based on Euler-Bernoulli beam theory, the differential equation of single shaft pipe with different lengths and shaft pipes with different length matching are built. Natural bending frequency and corresponding first critical speed is calculated, which is verified that the maximum rotational speed of researched transmission shaft is lower than the first critical speed, as a result, it can avoid resonance. To confirm the best kinetic performance series, five prototypes of transmission shaft are built, and analyze their kinetic performance, which will give a theoretical basis and simulation reference for the length matching of shaft pipe. Related Articles | Metrics

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The Study of Head Shape Parameters Based on the Glasses Wearing Area Zhang Jiaxin, Guan Shaoping, Li Zhelin, Zhang Xiaomin, Jiang Lijun, Yu Guangzheng 2016, 37(3): 410-416.  DOI: 10.11996/JG.j.2095-302X.2016030410 Abstract ( 131 )   PDF (4552KB) ( 277 )   Generally, glasses design in China is based on Caucasian head-face shape, as China is short of head-face data for glasses design. As a result, Chinese people usually find it is hard to buy a pair of suitable glasses. In this research, in order to discover the proper way of glasses design, the difference of Guangdong young man head-face shape with Kemar which is a average western head shape is compared based on the result of interviews from 136 glasses’ wearers. Through the study, it is found there are three parameters that influence the glasses design: how the difference of contour line of leg affect the design of leg form; how the contour line of ear impacted the ear piece’s design; how difference of face shape influence the design of nose pad and the pupillary distance influence the frame width. At last, we put forward the correct way for glasses design which would be used as an reference for the design of glasses. Related Articles | Metrics

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Locally Optimal Nonlinear Blind Detection Algorithm for Adaptive Multiplicative Watermarks in NSCT Domain Ye Jianbing, Zhang Wenbin 2016, 37(3): 417-427.  DOI: 10.11996/JG.j.2095-302X.2016030417 Abstract ( 69 )   PDF (796KB) ( 230 )   Research of image watermarking algorithms is an important issue in the field of multimedia technology. By comparing and combing the current two leading watermarking algorithms, an adaptive multiplicative watermarking algorithm is proposed. Motivated by Barni’s “pixel-wise masking” model and redundant wavelet domain masking effect modeling approach, the nonsubsampled Contourlet transform domain masking effect model is established. With generalized Gaussian distribution model and Cauchy distribution model to describe the statistical properties of the nonsubsampled Contourlet transform coefficients, the watermark detection problem is then addressed as a composite hypothesis testing. Theoretical analysis leads to two locally optimal nonlinear blind detectors for adaptive multiplicative watermarks as well as adaptive methods for determining detection thresholds. The experiment results show that the nonsubsampled Contourlet transform domain masking model achieves good visual invisibility, and watermarks can be accurately detected without using the original images and the adaptive embedding strength factors. In addition, Cauchy distribution based blind detector is found superior to the blind detector based on the generalized Gaussian distribution both in terms of detection performance and detection efficiency. Related Articles | Metrics

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A Corn Field of Remote Sensing Image Classification Method Based on Segmentation-Derived Regions and Feature Likeness Wang Xiaoxia, Yang Fengbao, Liang Ruofei, Feng Peipei 2016, 37(3): 428-433.  DOI: 10.11996/JG.j.2095-302X.2016030428 Abstract ( 84 )   PDF (4104KB) ( 249 )   Corn field remote sensing images have a mass of endmember spectral variability and complexity, that results in the bad classification of planting area. A corn field of remote sensing image classification method based on segmentation-derived regions and feature likeness is proposed. First, principal component analysis (PCA) is used to extract the first principal component from the fusion image which is fused by the panchromatic and multi-spectral image, to acquire the monochromatic image I which contains rich information. Then, do a Watershed segmentation to I, we can get a graph of a split target area. Then build characteristic group which is composed of texture, brightness and contour feature likeness. At last Based on the principle of random forests, extract the corn target using the characteristic group. With the testing using GF-1 satellite remote sensing data and the results comparison analysis of the support vector machine (SVM), neural network algorithm and maximum likelihood algorithm, it shows that the classification accuracy of this method is superior to other algorithms. Related Articles | Metrics

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Direction Estimation of Motion Blurred Images Based on Edge Detection of Spectrum and Radon Transform Jia Chunyan, Cui Li 2016, 37(3): 434-438.  DOI: 10.11996/JG.j.2095-302X.2016030434 Abstract ( 88 )   PDF (1589KB) ( 454 )   To accurately estimate direction of motion blurred images, in the part of theoretical derivation, the relationships among motion blur direction, image size and direction of parallel dark stripes in the spectrum images are derived based on knowledge of definite integral, Fourier transform and the Sinc function. In the part of algorithm optimization, the principle and deficiency of Radon transform, Gabor transform and spectrum sub–blocks method are analyzed. And then the improved algorithm based on edge detection of spectrum and Radon transform is presented. In the part of numerical experiments, by use of Matlab programs, comparison results of the three methods proved the accuracy of our improved method is the highest, which shows our method is more suitable for estimating direction of motion blurred images. Related Articles | Metrics

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Study of Subway Engineering on Cost and Schedule Combined Control Based on Building Information Modeling Chang Jianmei, Feng Huaiping 2016, 37(3): 439-442.  DOI: 10.11996/JG.j.2095-302X.2016030439 Abstract ( 258 )   PDF (464KB) ( 332 )   Currently subway project are rapidly developing in China. Many cities have subway construction demand. Large cost and tight schedule are the characteristics of subway engineering. Cost and schedule combined optimization is very necessary. In addition BIM technology has been widely researched and applied in engineering. But in the subway project, BIM is mainly used in modeling, collision checking, construction simulation etc. and the application in other areas is less. The application of aspects is often independent. In this paper, 3D + schedule + cost of construction management application is made based on BIM technology and earned value management method. For the subway station project, schedule and cost tracking are carried out. This paper has extended the application of BIM technology in the subway project. Related Articles | Metrics