Viewpoint manipulation for interactive television by using human pose estimation

In current interactive television schemes, the viewpoints should be manipulated by the user. However, there is no efficient method, to assist a user in automatically identifying and tracking the optimum viewpoint when the user observes the object of interest because many objects, most often humans, move rapidly and frequently. This paper proposes a novel framework for determining and tracking the virtual camera to best capture the front of the person of interest (PoI). First, one PoI is interactively chosen in a segmented 3D scene reconstructed by space carving method. Second, key points of the human torso of the PoI are detected by using a model-based method and the human’s global motion including rotation and translation is estimated by using a close-formed method with 3 corresponding points. At the last step, the front direction of PoI is tracked temporally by using the unscented particle filter (UPF). Experimental results show that the method can properly compute the front direction of the PoI and robustly track the best viewpoints.     

A closed form solution to segment 3D motion using straight-line optical flow

A closed form solution to the problem of segmenting multiple 3D motion models was proposed from straight-line optical flow. It introduced the multibody line optical flow constraint （MLOFC）, a polynomial equation relating motion models and line parameters. The motion models can be obtained analytically as the derivative of the MLOFC at the corresponding line measurement, without knowing the motion model associated with that line. Experiments on real and synthetic sequences were also presented.     

Voxelizating 3D mesh models with gray levels

A novel algorithm to voxelize 3D mesh models with gray levels is presented in this paper. The key innovation of our method is to decide the gray level of a voxel according to the total area of all surfaces contained by it. During the preprocessing stage, a set of voxels in the extended bounding box of each triangle is established. Then we travel each triangle and compute the areas between it and its set of voxels one by one. Finally, each voxel is arranged a discrete gray level from 0 to 255. Experiments show that our algorithm gets a comparatively perfect result compared with the prevenient ones and approaches the original models in a more accurate way.     

Research on the spherical capsule motion in 3D simple shear flows

Deformation of the spherical capsule in 3D simple shear flow is simulated using the immersed boundary method. The capsule membrane is regarded as an elastic medium satisfying the Neo-Hookean or Skalak elasticity. The motions of the capsule under various capillary numbers are studied. The results show that the deformation of the capsule becomes larger as the capillary number increases; in the same shear flow, the deformation under Skalak law is smaller than that under Neo-Hookean; for small capillary number the Taylor parameter agrees well with the analytical solution, whereas for large capillary number it is less than the analytical solution. Those results are validated by previous works obtained by the boundary integral method and the immersed boundary method.     

混凝土三维细观随机模型的建立和有限元剖分

将混凝土假定为由骨料和砂浆组成的两相复合材料, 研究了球形、椭球形和两者混合体的边界和干涉判断数学条件; 设计了球形、椭球形骨料随机投放算法, 并利用MATLAB编制相应程序, 生成了混凝土细观层次三维随机几何模型; 采用相邻骨料颗粒中心距判断球形骨料的干涉关系, 利用一个椭球上任一点与另一个椭球形心连线构成的直线段上的任一点与该椭球的关系判断椭球形骨料的干涉关系, 将两椭球之间的干涉关系转化为一点与椭球的关系; 基于MATLAB平台开发了mat2scr2017程序, 将MATLAB中的图形文件数据读入SCR脚本文件中, 将mat2scr 2017程序生成的随机骨料模型转化为AutoCAD图形文件, 并导入有限元软件COMSOL Multiphysics中剖分混凝土几何模型有限元网格。研究结果表明: 建立的随机骨料模型的骨料体积率可达到50%, 骨料粒径和投放位置均满足随机性要求; 椭球形随机骨料投放算法简单、高效, 且能保证椭球自身倾角的随机性; 模型适用于任意级配混凝土的生成, 对连续级配混凝土骨料的逐级随机投放保证了各级配骨料的体积率; 实现了MATLAB图形向AutoCAD图形的转换, 极大地提高了混凝土随机骨料模型的通用性; 所建混凝土模型网格剖分满足骨料、砂浆交界处网格一致性要求, 满足有限元分析的需要。     

开挖边坡的三维有限元稳定分析

用强度折减有限元方法对开挖边坡进行了三维稳定性分析．计算结果表明：对于约束效应不明显的开挖边坡,边坡的初始破坏面在边坡的中部,随着折减系数的增大,边坡的破坏由边坡中部向两侧扩展,最终边坡在空间上形成匙状或贝壳状的立体土体破坏;当边坡的纵向长度与开挖深度的比值大于4时,边界约束条件对边坡稳定安全系数影响不大,可以近似地按平面应变问题进行分析;对于角部约束效应明显的开挖边坡,当边坡中部剖面发生破坏,边坡角部剖面几乎也同时达到破坏,其稳定安全系数是按平面问题分析结果的1．3倍多,类似的实际问题如果按二维平面应变方法进行分析,其计算结果应用于工程设计中是偏于保守的．     

由平行切片图象重建血管的三维模型

CT图象可用于了解生物的组织结构，若摄取样木的数十，成百个平行切片，依次逐步分析并采样得到的各平行切片的CT图象，运用计算机就可重建其组织结构的准确的三维模型，本文提出了用数字矩阵表示CT图象的方法，定义了图象数字矩阵的“交、差、并、抽壳”的运算规则，并运用这些运算规则对血管切片的CT图象进行处理，求出血管中轴线与各平行切片的交点及血管的直径，运用OLE自动化技术控制AutoCAD实现血管三维图的重建。     

3D Numerical simulation of non-isothermal resin transfer molding filling process using unstructured tetrahedron mesh

We present a numerical formulation for resin flow based on the concept of quasi-steady state situation at the flow front. To be fit for complicated product shapes, we use the four-node unstructured tetrahedron mesh based on which the numerical formulation of temperature and degree of cure is developed. The validity of our method is established in the case where flexible meshes are used. The results show that the numerical procedure, tested on known data, provides numerically valid and reasonably accurate predictions.     

3D技术在航海专业课程教学中的应用

对比分析了我国与国外航海教育的现状,结合航海技术专业《船舶结构与设备》课程,将三维动画视频辅助教学的方式运用到该课程的实际教学工作之中,大大提高了课堂效率和教学效果,并对学生的职业技能与素质的提高有一定的益处。     

Numerical analysis of crack under compression by 3D displacement discontinuity method

A 3D displacement discontinuity method is applied to solve the fracture mechanics problems of the mixed mode crack under compression. Friction between the surface of the closed crack is considered by establishing a simple and efficient iterative algorithm based on method of contact resistance mitigation. On the surfaces of the closed crack, the Mohr-coulomb rule is satisfied by iteration when the crack is in condition of sliding. The stress intensity factors are obtained using displacement fitting method. It is shown that the numerical results agree with the experimental results well and that friction plays an important role in resisting crack propagation.     

Calculation of 3D sensitivity matrix for electromagnetic tomography system using boundary elements and the perturbative approach

Electromagnetic tomography （EMT） is a non-invasive imaging technique capable of mapping the conductivity and permeability of an object. In EMT, eddy currents are induced in the object by the activation coils, and the receiving coils can measure the EMT voltages. When the activation frequency is significantly large, we can treat the metallic targets as electrically perfect conductors （EPCs）. In this situation, a thin skin approximation is reasonable and this type of scattering problem can be effectively treated by the boundary element method （BEM） formulated through integration equations. In this study, we compute three-dimensional （3D） sensitivity matrix between the sensors due to an EPC perturbation. Efficiency improvement is achieved through the utility of scalar magnetic potential. Two EPC objects, one sphere and one cube shaped, are simulated. The results agree well with the H dot H formula. Overall, we conclude that BEM can be used to calculate the 3D sensitivity matrix of an EMT system efficiently. This method is a general one for any shaped objects while the H dot H solution is only capable of producing the response for a small ball.     

Back-analysis of the response of shield tunneling by 3D finite element method

This paper presents a numerical back-analysis of the response of a shield tunnel during construction. An important issue in the construction of shallow tunnels, especially in soft ground conditions, is the surface settlement caused by shield tunneling. The tunnel test system with 10 m length, 7 m width and 6.7 m height, which was completed in China in 2009, is a research shield tunnel system. Using shield tunneling technique known as earth pressure balance (EPB) and slurry shield method, it could be excavated in a region consisting of original soft soils, such as silty clay, and different types of underlain soft soils. Based on the test results, the real-life tunnel response can be analyzed by back-analysis technique. The back-analysis technique is adapted to the three-dimensional finite element method (FEM). Parameter analyses are calibrated to study the behavior of the multi-scale diameter tunnel under various conditions. The suggested multi-scale model results show a well agreement between the prediction and the measurement.     

Assessment of levator hiatus by 3D ultrasound volume contrast imaging in normal nulliparas

The ability of 3D ultrasound volume contrast imaging in C-plane (VCI-C) in the assessment of female levator hiatus was analyzed in eighty normal nulliparas. Interoperator variability in levator hiatus measurements was analyzed. The comparison of the axial image of magnetic resonance imaging (MRI) and C-plane image of volume contrast imaging (VCI) in thirty normal nulliparas was also done. It shows that VCI-C can clearly demonstrate the structure and accurately quantitates the size of the levator hiatus. It is reliable, convenient and without contraindication in assessment of female levator hiatus. The technology opens up entirely new modality for assessing female pelvic floor. Foundation item: the Scientific Research Project of Shanghai Municipal Health Bureau (No. 2008083)     

3D激光扫描仪测设路面平整度及病害研究

路面平整度及病害检测是道路工程研究的重要内容.基于静态的三维脉冲激光扫描技术在一定程度上可以弥补现有检测技术和方法的不足,实现快速、方便、大面积的测设.有较高的应用价值.     

3D激光扫描仪测设路面平整度及病害研究

路面平整度及病害检测是道路工程研究的重要内容.基于静态的三维脉冲激光扫描技术在一定程度上可以弥补现有检测技术和方法的不足,实现快速、方便、大面积的测设.有较高的应用价值.     

Neural Firing Mechanism Underlying Two-Electrode Discrimination by 3D Transcutaneous Electrical Nerve Stimulation Computational Model

Transcutaneous electrical nerve stimulation(TENS) has been widely used for sensory feedback which is a key consideration of improving the performance of prosthetic hands. Two-electrode discriminability is the key to realize high-spatial-resolution TENS, but the neural firing mechanism is not clear yet. The goal of this research is to investigate the neural firing patterns under two-electrode stimulation and to reveal the potential mechanisms. A three-dimensional(3 D) model is established by incorporating Aβ fiber neuron clusters into a layered forearm structure. The diameters of the stimulating electrodes are selected as 5, 7, 9 and 12 mm, and the two-electrode discrimination distance(TEDD) is quantified. It is found that a distant TEDD is obtained for a relatively large electrode size, and 7 mm is suggested to be the optimal diameter of stimulating electrodes. The present study reveals the neural firing patterns under two-electrode stimulation by the 3 D TENS model. In order to discriminate individual electrodes under simultaneous stimulation, no crosstalk of activated Aβ fibers exists between two electrodes. This research can further guide the optimization of the electrode-array floorplan.     

模糊层次分析与三维GIS集成的升压站选址方法

为了克服传统风电场升压站选址方法的局限性,基于模糊层次分析选址综合评价方法,在三维GIS中对升压站的选址进行了可行性比对分析. 首先从施工成本、选址地形因子、灾害指标、临近资源及障碍区域五个类别的准则建立风电场升压站选址递阶层次结构;其次集成三维地理信息系统与模糊层次分析法构建一种新的选址评估模型;通过预设几何初选规则获取模型输入参数,最终解算模糊评价矩阵实现升压变电站自动选址. 通过对不同地形的已建成风电场升压变电站选址结果进行比对研究实验表明:以风机分布区域范围内的2 m分辨率的数字高程模型作为实验数据,系统解算时间均在10 min内. 平原最佳选址的站址评分为0.957 8优于已建成站址评分0.941 2;山地最佳选址的站址评分为0.743 5优于已建成站址0.706 8. 该方法有效地提升了选址的时间效率且具备较高的精准性及较好的适用性.      

基于AutoCAD用仿形法实现斜齿轮加工仿真

主要介绍在AutoCAD的平台上,采用VBA开发工具,利用布尔运算,根据仿形法齿轮加工原理,对斜齿轮加工过程进行三维动态仿真。     

应用抑制性消减杂交技术筛选HBxAg蛋白结合蛋白XBP1的上调基因

目的应用酵母双杂交及生物信息学(bioinformatics)技术获得HBxAg蛋白结合蛋白XBP1,为了解该基因的反式调节机制,利用抑制性消减杂交技术筛选并克隆XBP1蛋白反式激活的靶基因。方法以XBP1表达质粒pcD-NA3.1(-)-myc-his(A)-XBP1转染HepG2细胞,以空载体pcDNA3.1(-)-myc-his(A)为对照;制备转染后的细胞裂解液,提取mRNA并合成cDNA,经RsaⅠ酶切后将实验组cDNA分成两组,分别衔接两种不同接头,再与对照组cDNA进行两次消减杂交及两次PCR反应,产物与T/A克隆载体连接,构建cDNA消减文库,并转染大肠杆菌进行文库扩增,随机挑选克隆经PCR鉴定后进行测序及同源性分析。结果成功构建人XBP1蛋白反式激活相关基因差异表达的cDNA。扩增后得到80个200～1 000bp插入片段的克隆,随机挑选其中30个插入片段测序,并通过生物信息学分析获得其全长基因序列,结果共获得28个已知编码序列基因和2个未知的新基因。结论 XBP1在肝细胞内表达后能够上调HepG2细胞中许多不同基因表达的变化,这些基因与细胞信号转导、细胞增殖与分化、免疫应答、能量代谢、细胞凋亡、肿瘤发生等生物过程密切相关。