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31 August 2019, Volume 40 Issue 4 Previous Issue    Next Issue

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Geometry Correction Method for Projection onto Spheres WANG Ming-dong1, GAI Meng2,3, LAI Shun-nan2,3, WANG Zhen4 2019, 40(4): 631-636.  DOI: 10.11996/JG.j.2095-302X.2019040631 Abstract ( 143 )   PDF (4966KB) ( 277 )   Abstract: A visual simulation system for flight simulation often uses multiple projectors to simultaneously project a surface to obtain a wider range of viewing angles. When the projector is tilted to the screen or the projection screen is a curved surface, the image is geometrically distorted. Aiming at this problem, this paper proposes a geometric correction method for the dome projection system. Taking a three-channel display system as an example, the present study describes the theoretical principle and correction process of the method in detail. The example results show that after geometric correction, each projection image has no geometric distortion, and the geometrical content of the channel transition is completely consistent. The method is a pure software method, which is small in cost and simple in operation, and can be adapted to different projection scenarios. Related Articles | Metrics

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Treatment of Solid Boundary Based on Velocity Correction ZHU Xiao-lin, CHEN Wei 2019, 40(4): 637-643.  DOI: ：10.11996/JG.j.2095-302X.2019040637 Abstract ( 52 )   PDF (745KB) ( 116 )   Abstract: The study of solid boundary treatment method has been a difficult problem in fluid simulation. The common methods of solid boundary treatment are boundary force method and virtual particle method. The boundary force method prevents fluid particles from penetrating the boundary by exerting force on the fluid particles near the boundary, but this method has too many parameters and the force is difficult to adjust, and the boundary truncation error will occur in the calculation. The virtual particle method solves the problem of boundary truncation error by generating virtual particles outside the boundary. However, when dealing with complex boundary problems, the generation of virtual particles is difficult, and the calculation accuracy will be affected due to the uneven distribution of virtual particles, which leads to particles to disperse. To solve these problems, the paper presents a new method for the treatment of solid boundary based on velocity correction, which does not need to solve the boundary force or generate virtual particles outside the boundary. The momentum equation and the velocity consumption are used directly to calculate the rebound velocity of the fluid particles when they hit the boundary, which greatly reduces the complexity of the boundary treatment. It also overcomes the problem of the instability of the boundary force method and the virtual particle method caused by the uneven sampling of particles at the corner of the boundary. Simulation results show that the proposed method is more stable and more efficient than traditional methods above, and with the increase of the number of particles, the time consuming of this method is also slower than that of the two methods, and the advantage of high computational efficiency is more obvious and the simulation effect of complex scene is also better. Related Articles | Metrics

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A Fast CPU/GPU Cooperative Modeling Method of Urban Rail Transport Lines LI Ming1, WEI Qing-chao1, LV Xi-kui2 2019, 40(4): 644-650.  DOI: 10.11996/JG.j.2095-302X.2019040644 Abstract ( 86 )   PDF (4286KB) ( 379 )   Abstract: Three-dimensional (3D) visualization can greatly improve the quality and efficiency of urban rail lines design. However, the traditional CPU-based method of 3D modeling have some problems in modeling speed, render efficiency, optimization scene, which require to be improved urgently. A fast 3D modeling method of urban rail transport lines based on CPU discrete-GPU modeling is proposed. Firstly, the line is divided into linear models and point models, and then, according to the results of line design, CPU is used to decompose linear models to obtain dataset of discrete boundary conditions. Subsequently, the point models are analysed to obtain dataset of spatial information parameters which can form, independent discrete data packets with a small amount of data respectively. Finally, with these discrete data packets, the fast modeling of 3D line model is achieved owing to the parallel computing ability of GPU. Combining the scene picking ability of CPU with the vertex expansion ability of GPU, a kind of scene optimization method that applies to long linear model display is established. The results show that ① The time-consumed by this method is only 0.55%–1.30% of the time using traditional CPU-based method. ② The proposed method is better than traditional CPU modeling method and scene management in browsing experience, minimum frames per second is higher than 70. ③ The performance indicators such as occupancy of memory and CPU are greatly improved, which help to lessen the pressure of design platform. ④ It provides significant implications for the 3D design of practical urban rail transport lines. Related Articles | Metrics

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An Extraction Method of Multi-LoD Dimension Information for  the Key Components of Ancient Wooden Architecture  Based on Salient Geometric Features SHI Li-wen1,2,3, XIE Lin-lin1,4, HOU Miao-le1,2,3, LI Ai-qun1,4, HU Yun-gang1,2,3, LIU Hao-yu1,2,3 2019, 40(4): 651-658.  DOI: 10.11996/JG.j.2095-302X.2019040651 Abstract ( 81 )   PDF (2635KB) ( 143 )   Abstract: For the assessment and improvement of the safety performance as well as historical and cultural inheritance of ancient wooden architecture, the dimension information of various key components of such architecture acts as the important foundation. However, an extraction method for such dimension information with high efficiency and accuracy is rarely reported. It is well acknowledged that the three dimensional (3D) laser scanning technology has the potential to provide a scientific solution for this problem. However, the point cloud data obtained by 3D laser scanning technology is usually enormous, and the dimension information herein cannot be directly obtained from this data. According to the important characteristics of the key component (i.e. multi-level of details (multi-LoD)) in ancient wooden architecture, a preliminary framework of multi-LoD models is proposed for various types of key components in the ancient wooden architecture, and the correspondingly salient geometric feature parameters, which aim to represent the dimension information of key components, are also recommended according to different LoD. Based on these multi-LoD models and massive high-fidelity point cloud data, an automatic extraction method of multi-LoD dimension information for the key components in ancient wooden architecture is proposed. This method is considered to be capable of accurately and efficiently extracting the multi-LoD dimension information of key components. To validate the reliability and high efficiency of this method, multi-LoD dimension information of two typical key components are extracted using the proposed method. The results indicate that this method is capable of extracting dimension information from millions of point cloud data within 7 minutes. Furthermore, the relative and absolute errors of such information are less than 2% and 0.5 mm respectively, thus validating the high efficiency and reliability of the proposed method. Related Articles | Metrics

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Real-Time Reconstruction of Multi-Angle 3D Human Faces  Based on Morphable Model CHEN Guo-jun, CAO Yue, YANG Jing, PEI Li-qiang 2019, 40(4): 659-664.  DOI: 10.11996/JG.j.2095-302X.2019040659 Abstract ( 91 )   PDF (2757KB) ( 282 )   Abstract: The method that uses face landmarks to adjust the 3D morphable model is widely applied in 3D face reconstruction, but the calculation of morphable model is time-consuming and often produces errors. In this paper, we improve the fitting method of general 3D morphable model using 2D landmarks of face, and propose a real-time 3D face reconstruction method with multiple angles of video frames. First of all, we recognize the location of landmarks by the CLNF algorithm with three-layer convolutional neural networks and track the landmarks. Then, the head posture is estimated from five senses of face landmarks, and the blendshape coefficients of the model is updated, which can be used to calculate the PCA shape coefficients so as to promote the deformation of the current 3D model. Finally, we employ the ISOMAP algorithm to extract the texture information of the mesh, and proceed texture fusion to form a specific face model. Experimental results demonstrate that our method has better real-time performance and accuracy in 3D face reconstruction. Related Articles | Metrics

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Feature Extraction of Facial Point Cloud Data for  Intelligent Spectacle Frame Fitting HOU Zeng-xuan1, LI Yan-xiang1, YANG Wu2, ZHAO You-hang1, WANG Jun-hua1 2019, 40(4): 665-670.  DOI: 10.11996/JG.j.2095-302X.2019040665 Abstract ( 93 )   PDF (1230KB) ( 134 )   Abstract: In order to extract the 3D facial point cloud in the intelligent spectacle frame fitting, a method of converting triangulated 3D point cloud into a mapped image is proposed to locate feature points. Firstly, the Gaussian curvature and mean curvature of each vertex of the face triangular mesh are calculated by Voronoi method. Secondly, nasal tip and canthus regions with obvious curvature features are used to estimate the facial point cloud orientation. According to the rotation invariance of surface curvature, the calculation of rotation matrix is simplified by using the point cloud orientation vector, so that the face point cloud faces the viewpoint. Then, the point cloud is transformed into an image by mapping, and the triangular faces in the 3D mesh model are mapped to the biunique triangles. The convolutional neural network is built and the Texas 3D Face Recognition Database is used for model training. Finally, face alignment is carried out and the predicted facial feature points are limited to a certain triangle of the image. According to the triangle mapping in the image, the corresponding triangular faces in the 3D mesh model can be found, and the coordinates of the facial feature points required by the spectacle frame fitting are calculated through the vertex coordinates of the triangular faces. Through the above steps, the feature extraction of spectacle frame fitting parameter is implemented. Related Articles | Metrics

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Palmprint Recognition Based on Fusing Global and Local Directional Features CHEN Xiao-man, JIA Wei, LI Shu-jie, LIU Xiao-ping 2019, 40(4): 671-680.  DOI: 10.11996/JG.j.2095-302X.2019040671 Abstract ( 71 )   PDF (987KB) ( 175 )   Abstract: Palmprint recognition is one of the most popular biometrics identification technologies. Among the various methods of palmprint recognition, the method based on directional features has achieved good results. In order to further improve the recognition accuracy, a palmprint recognition algorithm combining global and local directional features is proposed, which mainly combines the method based on directional coding, the method based on local descriptor of directional features and the method of combining directional features and correlation filters. The first two methods belong to the spatial domain method, which can extract the local directional features of the palmprint. The third method belongs to the frequency domain method, which can effectively extract the global directional features. The recognition results of the three methods are merged at the score level. The algorithm is validated on two palmprint databases. The experimental results show that the recognition performance of this method is better than other palmprint recognition methods. Related Articles | Metrics

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Real-Time Head Pose Estimation Based on RGBD CHEN Guo-jun, YANG Jing, CHENG Yan, YIN Peng 2019, 40(4): 681-688.  DOI: 10.11996/JG.j.2095-302X.2019040681 Abstract ( 131 )   PDF (1286KB) ( 242 )   Abstract: Real-time head pose estimation plays a crucial role in the application of human-computer interaction and face analysis, but accurate head pose estimation methods still face certain challenges. In order to improve the accuracy and robustness of the head pose estimation, this paper combines the geometry-based method and the learning-based method for head pose estimate. On the basis of face detection and face alignment, the geometric feature of the color image and the local area depth feature of the depth image are extracted, combining with the normal and curvature feature of the depth block to form the feature vector group, and then the random forest method is used to do the training. Finally, all decision trees are involved in the vote, and the resulting Gaussian distribution of the head pose is filtered by thresholds to further improve the model’s accuracy. Experimental results show that the proposed method has higher accuracy and robustness than the existing head pose estimation methods. Related Articles | Metrics

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A Vehicle Logo Recognition Method Based on Objective Optimization ZHU Wen-jia1, CHEN Yu-hong2, FENG Yu-jin2, WANG Jun3, YU Ye3 2019, 40(4): 689-696.  DOI: 10.11996/JG.j.2095-302X.2019040689 Abstract ( 59 )   PDF (1012KB) ( 143 )   Abstract: Vehicle logo recognition plays a more and more important role in intelligent transportation systems and has attracted extensive attention of researchers. Most traditional VLR methods are based on hand-crafted descriptors for which much heuristic knowledge is required, and thus are hard to adapt to complex and changeable realistic scenarios. Compared with hand-crafted descriptors, the feature learned methods perform betterin solving computer vision problems in complex environments. In the present study, a logo recognition method based on objective optimization learning is proposed to solve the VLR problem in this paper. First, feature parameters are automatically learned from pixel different matrix (PDM) extracted from raw images. Then, the PDMs are mapped into compact binary matrices with the learned feature parameters, and then the codebooks are learned from binary matrices with supervised learning. Finally, the feature vectors are extracted from test images with the learned feature parameters and codebooks. Experiments are carried out on open datasets HFUT-VL and XMU, and the results are analyzed and compared with other state-of-the-art methods. Experimental results show that our method can obtain higher recognition accuracy than hand-crafted descriptor based methods, and less training and testing time is required than deep learning based methods. Related Articles | Metrics

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Research on Simplification Algorithm of Dongba Hieroglyphic Feature Curve YANG Yu-ting1, KANG Hou-liang2, LIAO Guo-fu3 2019, 40(4): 697-703.  DOI: 10.11996/JG.j.2095-302X.2019040697 Abstract ( 101 )   PDF (862KB) ( 107 )   Abstract: Dongba hieroglyph is a primitive ideographic script. Many researchers have done a lot of research on the retrieval and recognition of Dongba hieroglyph, and applied various algorithms from different angles, but few of them are on the feature extraction and simplification. In view of the fact that the succinctness and completeness of character feature extraction will directly affect the accuracy and complexity of the recognition algorithm, we combine the related research of shape simplification in computer vision and present an improved algorithm which is helpful to the simplification of Dongba hieroglyph feature curve. Based on the discrete curve evolution algorithm, our algorithm further gives the critical point selection method based on the maximum area difference and the second simplification algorithm, which effectively remove the redundant points and potential anomalies in the character feature curve. The universality and robustness experiments show that our algorithm can remove more than 87% redundant points in the curve while retaining the original character features, and achieving the most simplified feature curve. It lays the foundation for retrieval and recognition of Dongba hieroglyph. Related Articles | Metrics

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Surface Defect Detection of Wind Turbine Blades Based on  RPCA and Visual Saliency CAO Jin-gang1, YANG Guo-tian2, YANG Xi-yun2 2019, 40(4): 704-710.  DOI: 10.11996/JG.j.2095-302X.2019040704 Abstract ( 80 )   PDF (2463KB) ( 209 )   Abstract: Aiming at the problem of surface defect detection of wind turbine blades, a method based on robust principal component analysis (RPCA) and visual saliency is proposed. Based on RPCA, the method adds the noise term and Laplacian regularization term to facilitate the segmentation of defect images, that is, suppressing Gaussian noise and uneven illumination by F-norm regularization term, and constraining the spatial relationship of pixels with Laplacian regularization term which can preserve invariance and the local consistency among the spatially adjacent sub-regions with similar saliency values in a saliency map. Firstly, superpixel segmentation and feature extraction are performed on the surface image of input wind turbine blades to obtain the feature matrix of the image. Then, the sparse matrix is obtained by the improved PRCA, and the saliency map of the defect region is calculated according to the sparse matrix and visual saliency method. Finally, the saliency map is optimized and the adaptive threshold segmentation algorithm is used to detect defects. Through experimental simulation, the experimental results are qualitatively and quantitatively analyzed, which indicates that the proposed method has high detection accuracy. Related Articles | Metrics

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Research on Stereo Matching Algorithms Based on Multi-Measure Fusion KANG Yu-xin, CHEN Gui-hui, DENG Yu, ZHANG Jun-hao 2019, 40(4): 711-717.  DOI: 10.11996/JG.j.2095-302X.2019040711 Abstract ( 73 )   PDF (2637KB) ( 251 )   Abstract: Aiming at the measure selection problem of stereo matching algorithm based on multi-measure fusion, a measure selection method based on measure complementarity coefficient is proposed. Using this method, the present study fuses multiple measures as the matching cost, and adopts the improved semi-global algorithm for cost aggregation to realize the stereo matching algorithm of multi-measures fusion. Firstly, the complementary coefficients are defined, and a variety of similarity measures are fused by the complementary coefficients as matching costs. Then, in attempt to solve the problem of poor stereo matching effect caused by semi-global cost aggregation using randomly initialized disparity map, we carried out the semi-global cost aggregation taking disparity based on SURF features as initial disparity. Finally, the disparities are calculated and optimized to obtain the final disparity map. The experimental results show that the complementary features can be selected by using the measure selection method, and the stereo matching effect can be improved by combining the improved semi-global cost aggregation method. Related Articles | Metrics

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Single Image Depth Estimation Based on Encoder-Decoder Convolution Neural Network JIA Rui-ming, LIU Li-qiang, LIU Sheng-jie, CUI Jia-li 2019, 40(4): 718-724.  DOI: 10.11996/JG.j.2095-302X.2019040718 Abstract ( 92 )   PDF (1344KB) ( 271 )   Abstract: Focusing on the poor robustness and lower accuracy in traditional methods of estimating depth in monocular vision, a method based on convolution neural network (CNN) is proposed for predicting depth from a single image. At first, fused-layers encoder-decoder network is presented. This network is an improvement of the end-to-end encoder-decoder network structure. Fused-layers block is added to encoder network, and the network utilization of multi-scale information is improved by this block with fusing multi-layers feature. Then, a multi-receptive field res-block is proposed, which is the main component of the decoder and used for estimating depth from high-level semantic information. Meanwhile, the network capacity of multi-scale feature extraction is enhanced because the size of receptive field is flexible to change in multi-receptive field res-block. The validation of proposed network is conducted on NYUD v2 dataset, and compared with multi-scale convolution neural network, experimental results show that the accuracy of proposed method is improved by about 4.4% in δ<1.25 and average relative error is reduced by about 8.2%. The feasibility of proposed method in estimating depth from a single image is proved. Related Articles | Metrics

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Real-Time Simulation of Water with Volume Conservation in Large Time Step ZHU Kui-xin1, GAI Meng2,3, LAI Shun-nan2 2019, 40(4): 725-732.  DOI: 10.11996/JG.j.2095-302X.2019040725 Abstract ( 103 )   PDF (5547KB) ( 128 )   Abstract: Physics-based fluid simulation can capture the movement of water. A common real-time simulation method is based on two-dimensional shallow water equation. Firstly, we introduce the two-dimensional shallow water equation, and then propose a new solution method, which is calculated by an implicit semi-Lagrangian method with volume conservation. This method allows a large time step while maintaining stability. Finally, we add additional correction steps to ensure volume conservation in the calculation process. In addition, a fluid solid coupling method based on momentum conservation is proposed, which works well. The model can simulate water more realistically in real time and ensure that the water volume is always conserved. Related Articles | Metrics

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Simplified Modeling and Simulation of Multi Rigid Body Dynamics Based on ADAMS WANG Kun, XING Hai-jun, XU Meng-chao, ZHANG Lin-hao 2019, 40(4): 733-738.  DOI: 10.11996/JG.j.2095-302X.2019040733 Abstract ( 164 )   PDF (1346KB) ( 346 )   Abstract: In ADAMS software, multi-rigid-body dynamics theory is applied to simplify the modeling and simulation of complex models, which is used to solve the complicated modeling process in ADAMS and the low computational efficiency of the simulation process. Firstly, the multi-rigid body dynamics of the simplified modeling method is analyzed. Then the specific procedure of simplified modeling based on ADAMS is put forward. The present study attaches great importance to a mathematical method that enables the central principal moment of inertia and the principal axis of central inertia of the original model and the simplified model to be of the same orientation. Finally, the simplified modeling method is applied to the roller coaster bicycle model, and the simulation results are compared and analyzed. The simulation results show that the simplified dynamic roller coaster model based on ADAMS is basically the same as the original model. This simplified modeling method can effectively improve the modeling efficiency of complex models in ADAMS and the computational efficiency of simulation. Related Articles | Metrics

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Methods of Human Robot Ergonomics Design of Restaurant Service Robot Based on QFD and RAHP WANG Qiu-hui, YANG Yue 2019, 40(4): 739-745.  DOI: 10.11996/JG.j.2095-302X.2019040739 Abstract ( 104 )   PDF (774KB) ( 158 )   Abstract: Based on the user demands, this study proposes a new human-robot system (HRS) mode of restaurant service robot, and discusses the method of applying the quality function deployment (QFD) theory to the design of human-robot ergonomics (HRE) for restaurant service robot. We use sampling survey, questionnaire survey and KJ to obtain hierarchical model of customer demand for restaurant service robot, introduce the rough analytic hierarchy process (RAHP) to calculate the weight of each demand feature, and analyze the key design objectives of the HRE design method based on quality function deployment. The crucial needs of users are transformed into design elements, then we set up the detailed demand characteristics of function, appearance and human-robot in HRE design. Through the house of quality to research on the quality function and get the design scheme, we use CATIA human-robot analysis software to evaluate the usability of the design scheme and verify the feasibility. The research results show this method has improved the usability of restaurant service robots and provided a reference for the subsequent designs. Related Articles | Metrics

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Study on Effect Mechanism of Time-Distance Perception on Motion Loading of Mobile Terminal FANG Hao, LI Meng-fan, WANG Zhong, CUI Shui-jing 2019, 40(4): 746-750.  DOI: 10.11996/JG.j.2095-302X.2019040746 Abstract ( 72 )   PDF (732KB) ( 115 )   Abstract: Motion loading of mobile terminal is an effective way to lessen users anxiety caused by when waiting for what is loaded. With regard to the design creativity, its important to explore how its design elements influence such anxiety caused by waiting. In the present study, time-distance perception is used to characterize the sense of anxiety while waiting. Through the prospective experimental paradigm and time-distance replication method, the time-distance perception experiment of the subjects in the simulated situation is carried out with speed and style as independent variables. The experimental results show that different types of motion loading all demonstrate a reduction on time perception, while the motion-loading speed exerts a more noticeable influence, notable, especially in the course of the acceleration. When the interaction of dynamic type and velocity has a significant influence on time perception, the time-distance perception of acceleration and cartoon combined loading is the shortest, and the time-distance perception of uniform speed and text class combined loading is the shortest, but deceleration and three dynamic styles combined loadings have no significant difference in the effect of time-distance perception. In conclusion, the users’ time-distance perception is related to the speed and type of motion loading via reasonable combination of speed and type which could effectively reduce users’ perception and then reduce their anxiety. The results of this study provide scientific evidences for mobile-loading motion design. Related Articles | Metrics

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Development and Application of a GIS-Based Light Weight Information Platform for Large-Scale Public Building Operation and Maintenance WEN Qiao1, ZHANG Jian-ping1, XIANG Xue-song2, SHI Tao2, HU Zhen-zhong3,1 2019, 40(4): 751-760.  DOI: 10.11996/JG.j.2095-302X.2019040751 Abstract ( 117 )   PDF (1195KB) ( 176 )   Abstract: Large-scale public buildings play an irreplaceable role in business, office, tourism, science, education, culture and health, communication and transportation. Due to technical difficulties, large public buildings usually lack operation and maintenance (O&M) management information platforms. To ease these difficulties, this paper presents an application method of lightweight O&M management platform for large-scale public buildings based on GIS. Large-scale public buildings’ drawings are converted into map services through conversion and editing. Attribute data are summarized to form hierarchical structures, and unique identifiers are given to establish standard attribute libraries. Based on these libraries, O&M management processes are reviewed to form standard O&M management procedures and data flows. A unified platform is developed to integrate the above 4 achievements before actual application. This method is tested in a large airport terminal. A lightweight O&M management platform is developed, which realizes the information O&M management of the terminal. The results have verified the effectiveness and operability of the proposed method. Related Articles | Metrics

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Compliance Check of Window-to-Wall Ratio in Revit Modeling YAN Xiu-ying1, WANG Xiu-dong1, LI Da-wei 2 2019, 40(4): 761-765.  DOI: 10.11996/JG.j.2095-302X.2019040761 Abstract ( 129 )   PDF (3740KB) ( 481 )   Abstract: In the process of building design, the window-to-wall ratio has noticeable effect on the energy consumption of indoor air conditioning and lighting. It is significant to control the window-to-wall ratio in a reasonable range for building energy saving. Aiming at the problem of window-to-wall ratio selection in Revit modeling process, this paper studies the calculation method of window-to-wall ratio. Based on the limit value of window-wall ratio given in Design Standard for Energy Efficiency of Public Buildings (GB50189-2015), Revit is redeveloped by C# language. The software of automatic enumeration algorithm of window-to-wall ratio is compiled and integrated into Revit to check the compliance of window-to-wall ratio in Revit model. The software is tested on an office building in Shanghai. The results show that the software can automatically obtain the ratio range of window-to-wall ratio in the building location, calculate the window-to-wall ratio of each facade of the current model and conduct the comparison. When it does not meet the specifications, the software can quickly adjust it to the norm range, and evaluate whether the optimized ratio of window area of each facade meets the requirements. Related Articles | Metrics

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Research on Fast and Accurate Modeling Method of BIM Parameterization for Highway Interchange WANG Ru, QUAN Chao-chao 2019, 40(4): 766-770.  DOI: 10.11996/JG.j.2095-302X.2019040766 Abstract ( 161 )   PDF (672KB) ( 249 )   Abstract: For the highway interchange project, because of its own complex spatial structure, miscellaneous intersection of curves, and complicated route across bridges, as well as the frequently varied elevation of bridge floor, great difficulties have been caused to the modeling work, and the design and modeling of large overpasses have always been a problem which urgently needs to be resolved in engineering field. Using BIM related software, according to the characteristics of highway interchange engineering, through the method of combining the BIM related modeling software with the visual programming plug-in Dynamo, this study discusses in detail the rapid construction method of real-time editable terrain model, main structure precision model and 3D model of the batch auxiliary facilities. The specific operation examples have shown that this method can improve the construction efficiency of the road interchange BIM model, there by promote the application of BIM technology in highway interchange engineering. Related Articles | Metrics

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Automatic Design Algorithm of Pile Foundation Cap Based on Revit ZHANG Wei-jin, CHEN Wu-qin 2019, 40(4): 771-777.  DOI: 10.11996/JG.j.2095-302X.2019040771 Abstract ( 135 )   PDF (642KB) ( 189 )   Abstract: The efficiency of constructing building information model by Revit is rather low. Based on Revit’s secondary development, in the absence of the CAD drawings of pile foundation caps, an automatic design algorithm for pile foundation cap is proposed by identifying the primitive information of the internal force diagram of the column (wall) generated by the structural analysis software. The method is based on the calculation of the eigenvalue calculation table of the vertical bearing capacity of the single pile in Revit. The algorithm program is written in C#. Then the pile foundation cap is automatically designed according to the requirements of the structure and the superstructure of the cap, and the pile caps satisfying the bearing capacity requirements are accurately arranged under the corresponding columns (walls), which significantly improves the efficiency of pile foundation engineering modeling, and facilitates the subsequent engineering calculations and economic comparison of different pile foundations. Related Articles | Metrics

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4D-BIM Based Quality and Safety Management for Qugang Highway ZHANG Chao 2019, 40(4): 778-782.  DOI: 10.11996/JG.j.2095-302X.2019040778 Abstract ( 100 )   PDF (1466KB) ( 184 )   Abstract: In order to improve the construction quality and safety management level of Qugang highway, this paper utilized 4D-BIM technology in a highway construction project. Construction safety and quality monitoring and analysis were carried out in highway quality and safety management, and a 4D-BIM time-varying structural safety analysis system was applied. This study introduces technologies such as the Internet of things, intelligent sensing technology, and digital monitoring to dynamically monitor the construction safety of key bridges and realize digital management of construction based on the Internet of things, thus improving the quality and safety management level of highway construction. This study provides methods and examples for the application of BIM in the quality and safety management of road construction, and is of great value for deepening the application of BIM in the construction phase. Related Articles | Metrics

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Service Product Design Based on Intangible Cultural Heritage and  Extension Semantics DUAN Jin-juan1, ZHANG Feng1, ZHOU Xin2 2019, 40(4): 783-789.  DOI: 10.11996/JG.j.2095-302X.2019040783 Abstract ( 139 )   PDF (778KB) ( 141 )   Abstract: An innovative product design method based on intangible cultural heritage (ICH) and extensible semantics is proposed aiming at the problem of insufficient effectiveness of implicit knowledge representation and transfer approach to ICH during the process of product innovative design using ICH. Representative cultural elements and cultural characteristics are extracted by analyzing the source culture, to establish the extensible semantic representation model, so as to acquire the quantitative relations between cultural characteristics and ICH. The paper calculates the extensible design space of cultural characteristics, converts it into graphical semantics by utilizing the graphical thought, to acquire the core graphical semantic set with the featured ICH elements based on extensible conversion. In addition, the paper constructs the extensible graphic element library, to provide basic materials for designs. By taking the model design for intelligent charging service facilities for electric cars as an example, this paper verifies the feasibility and the rationality of the approach. According to research findings, the extensible semantic analysis can be utilized to improve the extraction and utilization efficiency of ICH elements, providing supports for model designs of ICH innovative products. Related Articles | Metrics

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Automatic Inspection of the Radius Difference and Axis Coincidence of Matching Holes in Sheet Metal Parts LIU Fu1, DONG Yu-de1, WANG Liang1, SONG Jian1, WU Hai-jiang2, ZOU Wen-jun2, HUO Mei-ling2 2019, 40(4): 790-795.  DOI: 10.11996/JG.j.2095-302X.2019040790 Abstract ( 68 )   PDF (1045KB) ( 88 )   Abstract: Aiming at the problems of low precision and easy omission of the matching hole’s radius difference and the axis coincidence ratio in the automobile sheet metal parts, the automatic inspection method of the radius difference and the axis coincidence degree of the matching holes in the sheet metal parts is proposed. Firstly, the obtained B-Rep three-dimensional model is topologically decomposed into the basic unit of the face by the method of the closing shell. Secondly, according to the characteristics of two semicircular arc lines and two straight lines on the cylindrical surface, the cylindrical surface is screened, and the circular holes and slots are extracted by using the cylindrical surface. Then the radius and axis of the circular hole and the slot are obtained respectively, and the point-to-point and point-to-line distance method is used to check and analyze the matching hole according to the hole matching principle. Finally, the hole pairs whose radius difference does not meet the requirements and the axes do not coincide is marked. The system design of related algorithms is carried out by using CAA development platform of CATIA, and the feasibility of the method was verified. The example inspection results show that the method can automatically and accurately check the radius difference and the axis coincidence ratio of the matching holes in the sheet metal parts. Related Articles | Metrics

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Study on Optimal Design of Operating Interface of Large Mining Excavator ZHANG Hong-rui1, REN Jia-jun1, LI Ai-feng2, ZHAO Jing1 2019, 40(4): 796-801.  DOI: 10.11996/JG.j.2095-302X.2019040796 Abstract ( 110 )   PDF (1073KB) ( 129 )   Abstract: In view of the unreasonable layout of operating elements in large mining excavators, the elements of the man-machine interface of the excavator cab were quantitatively analyzed based on the ergonomic theory by the method of the improved Topsis method. Firstly, according to the operating frequency of each component in the excavator cab under different working conditions, the improved approximation ideal solution was used to prioritize each component. Secondly, in order to improve the operational convenience and work efficiency of drivers, user experience methods such as functional zoning principle and color design principle were comprehensively utilized to rearrange and design the operating components. Finally, the user interface of the redesigned layout and the original interface of current excavator were evaluated subjectively by using the 0-5 scoring table method. The results show that the user interface of the redesigned layout has higher human-computer interaction performance score than the former one. In Particular, in area division and component classification, they both have an optimization rate of about 40% and the average overall optimization rate is 35.4%. This method provides a design idea for rational planning and layout of the complex human-computer interface. Related Articles | Metrics

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Study on Stitching Simulation of the Miao Embroidery Art Style FENG Pei-chao, QIAN Wen-hua, XU Dan, PU Yuan-yuan 2019, 40(4): 802-809.  DOI: 10.11996/JG.j.2095-302X.2019040802 Abstract ( 122 )   PDF (6975KB) ( 71 )   Abstract: Non-realistic rendering (NPR) also known as artistic rendering, is mainly used to simulate artistic rendering style. With the continuous development of image processing technology, researchers have simulated the unique Chinese ink painting, pyrography, Yunnan heavy color painting and other art works in China. At present, digital simulation of the Miao embroidery is still in need. The Miao embroidery has already been approved by the state council to be included in the first batch of China’s national intangible cultural heritage list. Taking the Miao embroidery as the research object, this paper puts forward a painting method of the Miao embroidery artistic style with multi-angle stitches according to the characteristics of real the Miao embroidery artistic works. Firstly, aiming at the characteristics of exaggerated and clear composition of the Miao embroidery pattern, the gray level of the target image is processed, and multiple embroidery images are segmented by multi-threshold image processing method. Then, the morphological method is used to eliminate the spurious points, fill the void points and smooth the edges of the pattern. After that, a stitch generation algorithm based on spatial transformation of image matrix and adding longitudinal texture is used to generate stitch texture of the Miao embroidery at different angles for each embroidery image. By using the method of linear combination, the texture images of the Miao embroidery stitches are synthesized into texture images. Finally, the texture map and the target image of the Miao embroidery are superimposed by Alpha transparency hybrid algorithm to obtain the artistic features of strong color contrast of the Miao embroidery pattern and produce the effect image. Experiments show that this method can simulate the multi-angle stitch texture effect of the real Miao embroidery works. Related Articles | Metrics

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Research on the Design-Oriented Ornament Pattern  Gene Regeneration Algorithm ZHAO Hai-ying1,2, WANG Ting-ting1 2019, 40(4): 810-815.  DOI: 10.11996/JG.j.2095-302X.2019040810 Abstract ( 144 )   PDF (1909KB) ( 178 )   Abstract: The present study focuses on the key issue of how to add the cultural elements into the process of pattern generation, making the generation of patterns capable of inheriting certain cultural connotations. Taking the scroll pattern as the research object, which is representative of plant decoration pattern, the paper firstly proposes the concept of pattern culture gene, and then, a representative curve branch of a scroll pattern is used as its pattern culture gene. Considering the balance factor, the Runge-Kutta method is used as a generation rule to simulate the movement of particles in the vector field. The initial set of primitives is used by the generation rule to generate the scroll pattern. At the same time, the curve ID and the area ID are set to prevent the intersection or demarcation between different branches. Finally, the Runge-Kutta method is applied to redesign carpets, buildings, porcelain and paper cutting etc., for a better achievement of innovative applications and cultural inheritances. Related Articles | Metrics

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On Engineering Graphics Course Teaching Integration with  Model-Based Definition Technology YU Yong1, LIU Jing-hua1, ZHAO Gang1,2 2019, 40(4): 816-821.  DOI: 10.11996/JG.j.2095-302X.2019040816 Abstract ( 132 )   PDF (1222KB) ( 301 )   Abstract: Aiming at the teaching of engineering graphics, the present study introduces the three development stages of product definition technology from the perspective of engineering application, including two-dimensional design and two-dimensional drawing release, three-dimensional design and two-dimensional drawing release, and fully three-dimensional digital definition. The origin and application development of model-based definition technology are also introduced elaborated in this paper. The content and expression method of model-based definition dataset are introduced and analyzed by using Boeing 787 aircraft model. Referring to the geometric dimension and tolerance annotation method of aviation standard, taking cylindrical surface as an example, we discussed the teaching case of engineering graphics course integrated with model-based definition technology. The expressive content and method, advantages and disadvantages between two-dimensional engineering drawings and fully three-dimensional model-based definition dataset are compared and analyzed. Engineering graphics course integrated with model-based definition technology can not only increase the amount of classroom information, but also broaden the students’ knowledge and provide a good foundation for the following professional courses and practical application. In addition, it can stimulates the student’s interest in learning and scientific research, and promote the good interaction between scientific research and teaching. Related Articles | Metrics