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28 February 2017, Volume 38 Issue 1 Previous Issue    Next Issue

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View Frustum Culling Geometric Algorithm YU Haiyan1, ZHANG Shuai1, YU Peiwen1, HE Yuanjun2 2017, 38(1): 1-4.  DOI: 10.11996/JG.j.2095-302X.2017010001 Abstract ( 185 )   PDF (296KB) ( 276 )   From the point of view of geometry, a view frustum culling geometric algorithm is designed based on projective theory in descriptive geometry. The basic idea is that a proper computational coordinate system is built, where the space position relation of the view frustum and a line segment is transformed into the plane position relation of a trapezoid and the line segment by simple orthographic projection. This geometric dimension reduction method is beneficial to solve space geometric singular issue. A test sample is designed which includes all kinds of typical position relations of the view frustum and the line segment to comprehensively evaluate algorithm’s speed and stability. And especially, there are 78 kinds of geometric singular relations. At last, our view frustum culling geometric algorithm, classical Liang-Barsky algorithm and a basic algorithm to solvethe problem of intersection with 6 planes have been implemented on Visual C++ with C program. On the basement of qualitative analysis, these 3 algorithms have been tested on speed and stability. Related Articles | Metrics

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The Cutting Stock Problem of Circular Items Based on#br# Sequential Grouping Heuristic Algorithm CHEN Yan1,2, XIE Qiqi1, LIU Yong1, CUI Yaodong1 2017, 38(1): 5-9.  DOI: 10.11996/JG.j.2095-302X.2017010005 Abstract ( 91 )   PDF (549KB) ( 199 )   Aiming at the special application background of the small batch cutting problem of circular items, this paper introduces the thought of parallel group on the basis of sequential heuristic procedure, and presents the sequential grouping heuristic algorithm (SGHA) based on the group selection strategy. The SGHA combined with recursion method can generate a large number of optimal cutting plans, and the best cutting plan of circular items can be selected with the parameter regulation. Experimental result proves that the computational time is reasonable, the algorithm in this paper can improve the average utilization rate of material effectively, and it has a realistic significance. Related Articles | Metrics

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A Method for Three-Staged Two-Dimensional Guillotine Cutting with Usable Leftover CHEN Qiulian, SONG Renkun, CUI Yaodong 2017, 38(1): 10-14.  DOI: 10.11996/JG.j.2095-302X.2017010010 Abstract ( 118 )   PDF (438KB) ( 243 )   Reuse of leftovers is an important way for enterprises to reduce costs and environmental pollution. The paper solves the two-dimensional guillotine cutting stock problem considering the reuse value of the leftover. The beam search heuristic is used to generate three-staged homogenous cutting patterns of high material utilization and low processing complexity. The nodes consider both the value of included items and the reusability of the leftover. It makes a good balance between the low material costs of the current production cycle and the reusability of leftovers for future. The optimization process is demonstrated, and the computational results compared with literature. It shows that the algorithm can effectively save plate and generate standard leftovers. Related Articles | Metrics

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Improved Probability Iterative Closest Point Registration Algorithm ZHAO Fuqun1,2, ZHOU Mingquan2,3 2017, 38(1): 15-22.  DOI: 10.11996/JG.j.2095-302X.2017010015 Abstract ( 123 )   PDF (542KB) ( 231 )   Aiming at low convergence rate and failure registration brought by noise of iterative closest point (ICP) algorithm, a point cloud registration algorithm based on expectation maximum estimation is proposed in the paper, which is named improved probability iterative closest point (PICP) algorithm. Firstly, a point-to-point correspondence is built between two point cloud sets, and thus the registration accuracy is improved greatly. Then, Gaussian model is introduced into ICP algorithm, and the singular value decomposition method is used to calculate the rigid transformation. In the process of rigid transformation, the dynamic iteration coefficient is introduced to search the closest point rapidly in order to decrease iteration number and convergence rate without affecting the registration accuracy and convergence trend, and the accurate registration of two point cloud sets with noise is completed finally. The experimental results show that the improved PICP algorithm proposed is an accurate and fast algorithm which can effectively avoid noise and external interference. Related Articles | Metrics

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A Fast Method for 3D Solid Modeling of Topographic Map WANG Dazhi 2017, 38(1): 23-27.  DOI: 10.11996/JG.j.2095-302X.2017010023 Abstract ( 117 )   PDF (418KB) ( 337 )   Based on the topographic map of 3D modeling of AutoCAD platform, the accurate calculation of 3D visualization design is very important in earthwork engineering at the present stage. The general process of modeling 3D topographic map of a net surface is that a three-dimensional entity is stretched into by using of 2D polyline or 3D polyline. In this process, there are 20%–25% degradation of tensile objects, and it is needed to manually build triangle region, then these objects extruded. This is serious impact on modeling speed. The “boundary” function is called to generate a triangular irregular network area and then a sweep and lofting the interface function along the Z axis of the triangular mesh surface domain stretching formation of the three-dimensional object using coordinate transformation and contour data based on ObjectARX development technology. The fast terrain modeling is realized. Related Articles | Metrics

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Optimal Design of Bathtub Surface Based on Tekscan Pressure Measurement LI Zhelin, JIANG Lijun, HUANG Yurun, XIONG Zhiyong 2017, 38(1): 28-33.  DOI: 10.11996/JG.j.2095-302X.2017010028 Abstract ( 85 )   PDF (1392KB) ( 314 )   The bathtub has been widely used as household products. Due to the difference of height and weight of customers, the unreasonable surface shape will lead to low comfortability as using the product. In this paper, the pressure and the contact area are made as the evaluating parameters in order to design a suitable bathtub for adults. The surface of bathtub was redesigned according to percentile P5, P50, P95 of Chinese adult. The pressure and the contact area were measured by Tekscan instrument. The data which were captured from the ten testers lying in different bathtub with the original surface and the optimized surface was analyzed. Results shows that the peak pressure reduces to 58.4%–87.3%, the average pressure reduces to 83.6%–99.4%, and the contact area of the optimized surface increases to 1.50–2.78 times. The optimized surface effectively improves the comfortability of users. Related Articles | Metrics

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Optimal Nozzle Path Planning in 3D Printing LIU Jiawei, CHEN Shuangmin, WANG Xiaoli, XIN Shiqing 2017, 38(1): 34-38.  DOI: 10.11996/JG.j.2095-302X.2017010034 Abstract ( 83 )   PDF (437KB) ( 299 )   The key idea of the 3D printing technology lies in the layer-by-layer printing style, where designing the motion plan of the nozzle is a central constituent. It has at least three requirements: ① The nozzle has to go through each voxel defining the volume of the given 3D object; ② It’s better not to go through the same voxel multiple times; ③ The jumping from one voxel to a nonadjacent voxel should not be encouraged, or at least the jumping gap should be as small as possible. Based on the observations, the nozzle motion problem is transformed into the famous traveling salesman problem and then an improved backtracking algorithm used to find the solution. Furthermore, the best configuration of relevant parameters is given based on extensive experimental results. Related Articles | Metrics

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Research and Analysis on Internet Product Development System Based on ISM ZHANG Ruiqiu, LEI Shangzhong, HUANG Zhihui, LIU Na 2017, 38(1): 39-44.  DOI: 10.11996/JG.j.2095-302X.2017010039 Abstract ( 98 )   PDF (941KB) ( 235 )   It aims to clear vital influencing factors in Internet product development system, clarify the relationship between various factors, improve enterprise work efficiency and optimize development model. Qualitative and quantitative research was carried out on the Internet Company to extract influencing factors. Meanwhile work experience is as reference. The relationship model is established using the ISM. The adjacency matrix and matrix of direct or indirect relationship between influencing factors is formed using Boolean matrix. According to the hierarchical decomposition of matrix, the hierarchy of system is clear. Using hierarchy digraph outlines system schematic diagram and relationship between various factors. Relationship between system hierarchy models is established. It provides new ideas for the enterprise to improve the efficiency of product development and optimize the development process. Related Articles | Metrics

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Application of Extraction Model of Product Design Factors of Floral Culture XU Zhanmin, LI Yang 2017, 38(1): 45-51.  DOI: 10.11996/JG.j.2095-302X.2017010045 Abstract ( 99 )   PDF (5585KB) ( 414 )   How to inherit tradition and keep pace with the reasonable innovation is the key to cultural heritage in creative product design of tourism culture. The extraction of cultural design factors is difficult because it’s ambiguity and perceptual. With the development of floral tourism product design, the concept of floral-culture is put forward. The product design factor extraction model of floral-culture is built using the combination of qualitative and quantitative method. The product design factors are extracted from the aspects of form, color and flowery vocabulary. The design factor space of floral-culture is established, analyzed and extracted each factor in detail. Then the algorithms are tested. The hierarchy and judgment matrix is built between various factors with AHP. The contribution rate of each factor is calculated, and an algorithm for complete product design factor extraction model of floral-culture built. The model is applied in creative design of peony culture. The results showed that the extraction model is feasible and effective. Related Articles | Metrics

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The Design Factor Extraction and Application of Traditional Health Cultural WANG Weiwei, CHEN Mengmeng, LIU Yin, ZHANG Yujie 2017, 38(1): 52-56.  DOI: 10.11996/JG.j.2095-302X.2017010052 Abstract ( 89 )   PDF (6038KB) ( 249 )   With the development of social economy and the improvement of living standards, the importance of a healthy life for people gradually strengthen, preserving oneʼs health as a traditional philosophy of life is back. Through in-depth analysis of the core idea of keeping in good health culture, using the design of gene research methods, this paper discussed the train of thought of health cultural element extraction. Extracting the health cultural core design factors and visualizing these factors, using the analytic hierarchy process to evaluate and optimize the extraction scheme, finally combining with the characteristics of the design of smart watches, keeping in good health culture was put into the design of the modern smart products. Expressing unique oriental wisdom of Chinese culture on smart products, seeking new ideas for the wearable device design and promoting the development of smart wearable market to support traditional culture creative design activities and carry forward Chinese traditional culture. Related Articles | Metrics

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Segmentation of Industrial CT Image Based on Improved Exponential Cross Entropy and Glow-Worm Swarm Optimization MA Yinghui1,2, WU Yiquan2,3,4 2017, 38(1): 57-62.  DOI: 10.11996/JG.j.2095-302X.2017010057 Abstract ( 118 )   PDF (413KB) ( 226 )   To further improve the segmentation accuracy and processing speed of CT image in industrial CT detection system, the industrial CT image threshold segmentation was proposed based on 2-D exponential cross entropy and chaotic glow-worm swarm optimization. By using the minimum exponential cross entropy for threshold segmentation, the drawback of undefined value at zero of Shannon entropy was avoided. At the same time, 2-D histogram based on gray-gradient was taken to partition the object and background precisely in order to improve the anti-noise performance. In addition, chaotic sequence generated by cube map was used to initiate individual position for easy global searching, and chaotic glow-worm swarm optimization algorithm based cube map was used to search for 2-D optimal threshold in order to further increase algorithmic speed. Finally, a large number of experiments on industrial CT images were processed and then the experimental results were compared with 2-D entropy method based on firefly algorithm and minimum cross entropy method based on genetic algorithm. The obtained results show that the proposed method has obvious advantages in segmentation and processing speed. Related Articles | Metrics

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Hydrological Ruler Segmentation in Digital Hydrological Image LENG Jianwei1, SHEN Fangting2 2017, 38(1): 63-68.  DOI: 10.11996/JG.j.2095-302X.2017010063 Abstract ( 93 )   PDF (2347KB) ( 260 )   To aim at the characteristics of the hydrological monitoring video images, such as the high signal to noise ratio and the obvious color differences among targets and the specific location of target regions, a water level reading method is proposed with strong practicability and little interference from external factors. Due to the fixed content of cameras and only blue and red scales of hydrological rulers, it extracts color components according to the characteristic color of the ruler. After determining the adaptive threshold, the image is changed with the binary processing, denoised and morphological processing. The ruler successfully is segmented using Hough transform to determine the boundary of the hydrological ruler. All these work for reading real-time water level by edge detecting. The experiment results show that this method can quickly segment and get the region of interest efficiently.   Related Articles | Metrics

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Low Dimension Discriminant Analysis on Grassmann Manifold ZENG Qingsong, ZHONG Runlu 2017, 38(1): 69-75.  DOI: 10.11996/JG.j.2095-302X.2017010069 Abstract ( 127 )   PDF (1102KB) ( 288 )   The key issues of video based face recognition are the way to model facial images precision and high efficiency and measure the similarity between two sets. To end this, a Grassmann manifold dimension reduction method is proposed to improve the performance of image set matching. Firstly, a subspace constructed by an image set is presented as a point in a Grassmann manifold with a projection matrix. Then, a projection metric learning approach is applied to reduce the dimension of the orthogonal basis matrix to obtain a lower dimension and tighten Grassmann manifold. Finally, a kernel function mapped the orthogonal basis matrix from a Grassmann manifold to Euclidean space for classification. Extensive experimental results on shared video based dataset show that the proposed method is an effective object matching and face recognition method based on set-to-set matching. Related Articles | Metrics

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Fast Video Shot Boundary Detection Algorithm Based on Map Reduce ZHENG Huijun1, CHEN Yuqiang1,2 2017, 38(1): 76-81.  DOI: 10.11996/JG.j.2095-302X.2017010076 Abstract ( 154 )   PDF (393KB) ( 225 )   Shot boundary detection is the foundation of video indexing, retrieval and analysis. However, the huge amount of data and the high computational cost in shot detection becomes a bottleneck in the practical application. Using the distributed computing of Map Reduce model, a large number of video data processing operations is splinted into several independent Map tasks for video decoding and feature extraction. Then the feature value is detected by several Reduce tasks to get the final shot boundary set. When extracting the features, the video is divided into 31 frames segment, using the histogram of block with weight to calculate the difference between first frame and last frame of the video segment. Through the adaptive threshold filtering out the non-boundary segments and the candidate segments, the further detection has been done for the candidate segments. The twice frame difference method of non-neighboring frame is proposed for the gradual shot detecting. Experimental results show that the Map Reduce model and the improved shot detection algorithm is effective in accelerating the shot detection process, and it can also achieve better detection accuracy. Related Articles | Metrics

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G-LBP and Variance Cross Projection Function for Face Recognition HU Min1, YU Zixi1, WANG Xiaohua1, REN Fuji1,2, HE Lei3 2017, 38(1): 82-89.  DOI: 10.11996/JG.j.2095-302X.2017010082 Abstract ( 182 )   PDF (1013KB) ( 330 )   In order to enhance robustness of traditional Gabor features towards illumination, expression and pose variance and overcome its high dimension problem, the paper proposes a face recognition method based on Gabor, local binary patter and variance projection entropy improved algorithm. First, the multi direction multi-scale fusion Gabor image is coded with LBP, and the coded image fused and the histograms of image block calculated. Second, a local projection entropy feature extraction is adopted for face images with anti-geometric distortion variance projection entropy and cross variance projection entropy operator. Finally, the face recognition is completed by using BP neutral network to fuse and make decision weightily. The G-LBP feature extraction reduces the redundancy of data greatly, and maintains the integrity of the effective information. Variance projection of entropy and cross entropy improves the richness of the feature. The weighted fusion in decision-making layer plays an important role of integration between the classifiers and improves the recognition rate of face recognition. Compared with other literature algorithms, experiment results verify the effectiveness and superiority of the proposed algorithm. Related Articles | Metrics

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3D Medical Image Registration Based on Clifford Relative Invariant and Region of Interest HUA Liang, CHENG Tianyu, GU Juping, YU Kean 2017, 38(1): 90-96.  DOI: 10.11996/JG.j.2095-302X.2017010090 Abstract ( 125 )   PDF (742KB) ( 372 )   A region of interest (ROI) is delineated based on the registration by using the geometric features of skull contour, and a new construction method of relative invariants put forward under the framework of Clifford algebra. The method proposed regards the contour data of ROI in the skull as the point cloud for registration, and constructs the mathematical and calculation models of the relative geometric invariants according to the similarity of skull contour. After calculating the translation and the rotation operator required for the registration algorithm, the registration of three-dimensional data can be preceded directly by adopting the new similarity measure of the 3D medical image. The registration data are from the BrainWeb database and “Retrospective image registration evaluation” project data of the University of Vanderbilt in the United States. Experiments show that our algorithm has high efficiency in the registration of ROI in the skull. And it can calculate the 3D position of the tissue organ more accurately. The mean error is within 2-4 mm, and the registration accuracy is up to sub-pixel level. Related Articles | Metrics

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A Phased and Progressive Modeling Method of BIM YU Fangqiang1, ZHANG Jianping2 2017, 38(1): 97-101.  DOI: 10.11996/JG.j.2095-302X.2017010097 Abstract ( 216 )   PDF (1198KB) ( 396 )   BIM technology has been rapidly developed over the past 10 years. However, it’s still difficult to deliver information smoothly between different phases due to that there are many participants involved in a building project. Consequently, a completed BIM still can’t be constructed. To address this problem, this paper proposes a phased and progressive modeling method (PPMM) of BIM, together with a basic agreement for cooperative modeling among all participants, and modeling procedures. The method supports various participants to cooperatively create BIM under a unified framework. Being verified by a real project, the PPMM is effective for preventing from repetitive modelling and inconsistent data, and is helpful for generating a completed and consistent BIM in BIM database, which is a foundation of building lifecycle-oriented BIM application. Related Articles | Metrics

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Discussion about Reform of Civil Engineering Course System Based on BIM Talent Training HE Rui, LUAN Yingyan, GAO Dai 2017, 38(1): 102-108.  DOI: 10.11996/JG.j.2095-302X.2017010102 Abstract ( 201 )   PDF (19692KB) ( 202 )   Building information modeling (BIM) is a new technology in architecture field and wildly used in Europe and USA by its low cost, high efficiency, visualization and data sharing. To apply BIM is accelerate in China Construction Department “Twelfth Five Year Plan”. According to the BIM talent gap problem with cutting-edge technologies, civil drawing course including manual drawing, AutoCAD and BIM are given by Harbin Industrial University. Two rounds of teaching results show that the introduction of three-dimensional teaching is conducive to improve students’ ability to read civil drawings and also stimulate students' interest in active learning. Related Articles | Metrics

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Application and Research on Teaching Reform in CAD Course for Civil Engineering Majors Combining with BIM Technology SUN Ming, HU Nini 2017, 38(1): 109-113.  DOI: 10.11996/JG.j.2095-302X.2017010109 Abstract ( 109 )   PDF (201KB) ( 338 )   Based on the current situation of CAD course teaching in applied local university and building information modeling (BIM) technology, a reform is carried out from two aspects that is on CAD course combining with BIM technology and exploration of teaching practice. It also puts forward to apply AutoCAD, TArch, and Revit into project task-driven classroom instruction and homework arrangement so as to improve students’ subjective initiative in study, and cultivate excellent applied engineers who can meet market demands and the requirement of the developing trend in the future. Related Articles | Metrics

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The Reform and Practice of Engineering Graphics Courses in Applied University LI Yugen, MA Xiaoli, LI Dongmei, HU Dawei, DONG Ru 2017, 38(1): 114-118.  DOI: 10.11996/JG.j.2095-302X.2017010114 Abstract ( 137 )   PDF (461KB) ( 257 )   Based on the three civil engineering majors of applied local campus Yulin University for example, the lack of engineering graphics courses teaching is analyzed combining with questionnaire survey results. The graphics course group is built by training applied ability. The whole process of graphics skills training is concluded by participation of school and enterprises with reforms of learning interesting training, the teaching content selecting, second classroom teaching and other aspects. Explored teaching new mode of engineering graphics courses under the background of transformation to train the depth and breadth of graphics skills of students and service the local economy. The results show that the reform measures can improve the students’ ability of graphics applications. Related Articles | Metrics

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Cultivating Design Innovation Ability of the Students Based on 3D Engineering Drawing YAO Yan 2017, 38(1): 119-122.  DOI: 10.11996/JG.j.2095-302X.2017010119 Abstract ( 99 )   PDF (374KB) ( 297 )   After study the inevitability of engineering drawing from 2D teaching mode to 3D, the advantages and disadvantages of various 3D engineering graphics teaching modes are compared. Then a new teaching mode–improved main line mode is put forward which is based on the 3D engineering graphics to cultivate students’ creative ability. The practice proved that the new teaching mode is useful. Related Articles | Metrics

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The Innovation and Practice of Engineering Drawing Teaching Based on All-Around Opening Labs LIU Ying, LI Kai, CAO Mo, LI Leyi 2017, 38(1): 123-127.  DOI: 10.11996/JG.j.2095-302X.2017010123 Abstract ( 77 )   PDF (3206KB) ( 241 )   This paper introduces a method of introducing all-around opening labs to the class teaching of engineering drawing, and many practicing instances are given. This teaching mode is based on students’ self-lab-management, case-driven micro lecture learning, and the combination of class teaching and opening lab practicing. It has been successfully run for more than 3 years, and large quantity of excellent students’ works have been accomplished, which proves that it is very effective to improve student’ s learning interests, practicing ability and innovation consciousness. This mode is replicable. Related Articles | Metrics

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Numerical Analysis of Slope Stability Based on XFEM CHANG Jianmei, SONG Siwen 2017, 38(1): 128-131.  DOI: 10.11996/JG.j.2095-302X.2017010128 Abstract ( 77 )   PDF (353KB) ( 307 )   It is obvious phenomenon that cracks exist in the upper part of slope. This paper considers that the failure of slope is caused by composition of crack and shear, but not single shear failure. Tension and Mohr-Coulomb shear failure is discussed in the analysis of slope and the just connection between the shear failure zone, and crack is regarded as the criterion of sliding failure of slope. Extended finite element method is adopted to simulate the cracking of tension. Unified enrichment function is used in the approximation of discontinuous field in which mixing element is avoided and the enrichment freedom has significance. The simulation results show that if the tension failure is not taken into account, the factors of safety of slope stability are higher. Therefore, it is necessary to consider the tension failure of soil. Meanwhile, the length of the crack of tension is longer than the theoretical ones. It can be used as reference for the judgment of critical sliding surface. Related Articles | Metrics

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Design and Practice of Mobile Learning Resources of Computer Graphics Course LI Zhixiang 2017, 38(1): 132-136.  DOI: 10.11996/JG.j.2095-302X.2017010132 Abstract ( 92 )   PDF (935KB) ( 190 )   Mobile learning is an effective complement to the modern distance learning, as it can be accessible from virtually anywhere and anytime. The mobile learning resources is designed and developed on the basis of the analysis of course characteristics and the existing issues of teaching. Combining task-driven, process evaluation and fragmented learning, the mobile learning resources emphasize learning in using. It provides a useful exploration for teaching practice of computer graphics course. Related Articles | Metrics