Robust Symmetry Prediction with Multi-Modal Feature Fusion for Partial Shapes

In geometry processing,symmetry research benefits from global geo-metric features of complete shapes,but the shape of an object captured in real-world applications is often incomplete due to the limited sensor resolution,single viewpoint,and occlusion.Different from the existing works predicting symmetry from the complete shape,we propose a learning approach for symmetry predic-tion based on a single RGB-D image.Instead of directly predicting the symmetry from incomplete shapes,our method consists of two modules,i.e.,the multi-mod-al feature fusion module and the detection-by-reconstruction module.Firstly,we build a channel-transformer network(CTN)to extract cross-fusion features from the RGB-D as the multi-modal feature fusion module,which helps us aggregate features from the color and the depth separately.Then,our self-reconstruction net-work based on a 3D variational auto-encoder(3D-VAE)takes the global geo-metric features as input,followed by a prediction symmetry network to detect the symmetry.Our experiments are conducted on three public datasets:ShapeNet,YCB,and ScanNet,we demonstrate that our method can produce reliable and accurate results.

Information perception and feedback mechanism and key techniques of multi-modality human-robot interaction for service robots

With the increasing of the elderly population and the growing hearth care cost, the role of service robots in aiding the disabled and the elderly is becoming important. Many researchers in the world have paid much attention to heaRthcare robots and rehabilitation robots. To get natural and harmonious communication between the user and a service robot, the information perception/feedback ability, and interaction ability for service robots become more important in many key issues.

Interactions of penny-shaped cracks in three-dimensional solids

The interaction of arbitrarily distributed penny-shaped cracks in three-dimensional solids is analyzed in this paper. Using oblate spheroidal coordinates and displacement functions, an analytic method is devel- oped in which the opening and the sliding displacements on each crack surface are taken as the basic unknown functions. The basic unknown functions can be expanded in series of Legendre polynomials with unknown coefficients. Based on superposition technique, a set of governing equations for the unknown coefficients are formulated from the traction free conditions on each crack surface. The boundary collocation procedure and the average method for crack-surface tractions are used for solving the governing equations. The solution can be obtained for quite closely located cracks. Numerical examples are given for several crack problems. By comparing the present results with other existing results, one can conclude that the present method provides a direct and efficient approach to deal with three-dimensional solids containing multiple cracks.

Interaction of a parabolic-shaped pulse pair in a passively mode-locked Yb-doped fiber laser

We numerically investigate the formation and interaction of a parabolic-shaped pulse pair in a passively mode-locked Yb-doped fiber laser. Based on a lumped model, the parabolic-shaped pulse pair is obtained by controlling the intercavity average dispersion and gain saturation energy, Moreover, pulse repulsive and attractive motion are also achieved with different pulse separations. Simulation results show that the phase shift plays an important role in pulse interaction, and the interaction is determined by the inter-cavity average dispersion and gain saturation energy, i.e., the strength of the interaction is proportional to the gain saturation energy, a stronger gain saturation energy will result in a higher interaction intensity. On the contrary, the increase of the inter-cavity dispersion will counterbalance some interaction force. The results also show that the interaction of a parabolic-shaped pulse pair has a larger interaction distance compared to conventional solitons.

A simplified approach for negative skin friction calculation of special-shaped pile considering pile-soil interaction under surcharge

A simplified approach was proposed to analyze the negative skin friction calculation of special-shaped pile considering pile-soil interaction under surcharge. Based on the concentric cylinder shearing theory, considering the changes of pile shape(such as, taper angle and diameters of pile base, etc.), the load-transfer of special-shaped pile was built. The accuracy of the developed simplified approach was verified by numerical simulation model with the same condition. Then, the influence factors, such as, taper angles, the diameter of pile base, surcharge, and pile-soil interface parameters were analyzed and discussed. The results show that the developed simplified approach can calculate NSF of special-shaped pile under surcharge effectively. A limited parametric study indicates that in many practical situations special-shaped piles(such as belled wedge pile shown in this work) offer a design option that is more economical than traditional uniform cross-section piles.

An intelligent navigation experimental system based on multi-mode fusion

At present,most experimental teaching systems lack guidance of an operator,and thus users often do not know what to do during an experiment.The user load is therefore increased,and the learning efficiency of the students is decreased.To solve the problem of insufficient system interactivity and guidance,an experimental navigation system based on multi-mode fusion is proposed in this paper.The system first obtains user information by sensing the hardware devices,intelligently perceives the user intention and progress of the experiment according to the information acquired,and finally carries out a multi-modal intelligent navigation process for users.As an innovative aspect of this study,an intelligent multi-mode navigation system is used to guide users in conducting experiments,thereby reducing the user load and enabling the users to effectively complete their experiments.The results prove that this system can guide users in completing their experiments,and can effectively reduce the user load during the interaction process and improve the efficiency.

Interactive Restoration of Three-Dimensional Implicit Surface with Irregular Parts

Implicit surface generation based on the interpolation of surface points is one of the well-known modeling methods in the area of computer graphics.Several methods for the implicit surface reconstruction from surface points have been proposed on the basis of radial basis functions,a weighted sum of local functions,splines,wavelets,and combinations of them.However,if the surface points contain errors or are sparsely distributed,irregular components,such as curvature-shaped redundant bulges and unexpectedly generated high-frequency components,are commonly seen.This paper presents a framework for restoring irregular components generated on and around surfaces.Users are assumed to specify local masks that cover irregular components and parameters that determine the degree of restoration.The algorithm in this paper removes the defects based on the user-specific masks and parameters.Experiments have shown that the proposed methods can effectively remove redundant protrusions and jaggy noise.

Free Transverse Vibration Analysis of an Underwater Launcher Based on Fluid-Structure Interaction

一个灵魂发射台理论上被调查在水里学习它的自然横向的颤动。就封上的盖子的集体效果而言，发射台与一个最高的点团作为一根一致伸臂横梁被简化。由介绍边界和连续性条件进运动方程，自然频率方程和模式形状功能被导出。为增加的质量的一个反复的计算方法也用速度潜力函数被介绍在发射台上说明液体的集体效果。开始的 2 顺序天赋频率和模式形状在外部流动领域和外部、内部的流动领域里被讨论。结果证明对在理论分析和 FEM 之间的自然频率和模式形状的好同意学习。另外，增加的团被发现随发射台的模式形状订单的增加减少。并且因为在两个的更大的增加的团，外部、内部的流动比在仅仅外部流动地里，前者的相应自然频率相对更小的回答。

Eye-shaped keyboard for dual-hand text entry in virtual reality

We propose an eye-shaped keyboard for high-speed text entry in virtual reality (VR), having the shape of dual eyes with characters arranged along the curved eyelids, which ensures low density and short spacing of the keys. The eye-shaped keyboard references the QWERTY key sequence, allowing the users to benefit from their experience using the QWERTY keyboard. The user interacts with an eye-shaped keyboard using rays controlled with both the hands. A character can be entered in one step by moving the rays from the inner eye regions to regions of the characters. A high-speed auto-complete system was designed for the eye-shaped keyboard. We conducted a pilot study to determine the optimal parameters, and a user study to compare our eye-shaped keyboard with the QWERTY and circular keyboards. For beginners, the eye-shaped keyboard performed significantly more efficiently and accurately with less task load and hand movement than the circular keyboard. Compared with the QWERTY keyboard, the eye-shaped keyboard is more accurate and significantly reduces hand translation while maintaining similar efficiency. Finally, to evaluate the potential of eye-shaped keyboards, we conducted another user study. In this study, the participants were asked to type continuously for three days using the proposed eye-shaped keyboard, with two sessions per day. In each session, participants were asked to type for 20min, and then their typing performance was tested. The eye-shaped keyboard was proven to be efficient and promising, with an average speed of 19.89 words per minute (WPM) and mean uncorrected error rate of 1.939%. The maximum speed reached 24.97 WPM after six sessions and continued to increase.

高斯与平顶光束纳秒脉冲激光物质蒸发烧蚀动力学仿真研究

基于建立的纳秒脉冲激光与金属铝相互作用的二维轴对称模型,仿真研究了光束整形对纳秒脉冲激光烧蚀金属铝过程中蒸发烧蚀动力学的影响.结果表明:等离子体屏蔽对靶材的烧蚀特性具有显著影响,屏蔽效应主要体现在脉冲的中后期.对于3种激光轮廓,高斯光束的屏蔽效果最强,随着整形后的平顶光束直径的增大,屏蔽效果逐渐减弱.平顶光束与高斯光束作用下,靶材温度的二维空间分布较为不同.高斯光束作用时,靶材中心最先升温,随后温度沿径向和轴向扩散.由于平顶光束的能量分布更加均匀,因此一定径向范围内的靶材同时升温.光束整形对靶材的蒸发烧蚀动力学影响较大.对于高斯光束,靶材中心先烧蚀,随后产生径向烧蚀.由于整形后平顶光束的能量密度降低,因此靶面蒸发时间较高斯光束延后,并且一定径向范围内的靶材同时发生蒸发烧蚀.3种激光轮廓下,靶材的蒸发烧蚀形貌与光束的强度分布类似,其中高斯光束的烧蚀坑呈中间深两边浅的特点,平顶光束的烧蚀坑较为平坦.

活性浴中惰性粒子形状对有效作用力的影响

活性物质是典型的非平衡态系统,其组成单元能够利用自身存储的能量或者周围环境的能量实现自驱动.在活性系统中,物体间的受力情况直接影响其结构和动力学行为,因此深入了解物体间的有效作用力是理解活性物质一切复杂现象的基础.本文通过光镊显微镜实验分别研究了活性大肠杆菌溶液中惰性球形聚苯乙烯胶体粒子间和板状粒子间的有效作用力,发现球形粒子间有效作用力的性质一直是短程排斥力,而板状粒子间的有效作用力则为长程吸引力,这说明惰性粒子间的有效作用力受粒子形状的影响.惰性粒子间的有效作用力主要来源于两部分的贡献,即细菌-惰性粒子间的直接碰撞,以及细菌运动产生的流场.在实验上通过对比粒子之间、粒子外侧细菌的浓度和取向有序性发现,球形粒子间的有效排斥力主要来源于细菌-粒子的直接碰撞,而板状粒子间的长程吸引力则主要源于细菌流场的贡献.本文通过光镊显微镜实验证明了惰性粒子间的有效作用力与惰性粒子的几何构型有关,为调控活性物质中的动态自组装提供了实验支撑.

基于交互式目标分割算法的影视后期抠像方法研究

快速准确地提取出视频中的目标物体是影视后期抠像的关键环节,因此研究基于交互式目标分割算法的影视后期抠像方法。采用优化后的三帧间差分法检测影视后期视频图像内的感兴趣区域(ROI),以CV模型为基础,结合形状先验引导进化思想构建交互式目标分割模型,将待分割图像的先验形状信息与图像内实际目标轮廓信息作为交互信息,在交互式目标分割模型内引入面积激励项,由此在影视后期视频图像内ROI区域内分割出目标。将分割出的图像目标与待替换背景视频图像合成,完成影视后期抠像。实验结果显示,该方法能够有效确定视频图像中的ROI区域,在模型迭代30次条件下即可获取高精度的目标分割结果,抠像过程中的图像轮廓收缩率均控制在0.45以下。

钢中不同形状夹杂物在超重力场中上浮模拟研究

超重力可促使夹杂物快速上浮,缩短其在钢液中的上浮时间.为研究夹杂物形状对其在钢液中的上浮行为的影响,本文使用流固耦合方法跟踪计算流体与固体界面状态,在二维纵切面中构建了三种具有不同形态比的夹杂物并在超重力场中进行上浮行为模拟研究.结果表明,夹杂物的上浮速度与自身形状和上浮角度有关,形态比越趋近1或上浮角度越接近垂直,上浮速度越快.在重力系数G=1000的超重力场中,长度为1μm的夹杂物未发生旋转.长度为10、20μm的夹杂物会自初始角度(45°、90°)旋转至水平后稳定上浮.超重力系数会影响夹杂物的旋转状态,随着重力系数的降低,夹杂物的旋转速度逐渐降低.当G=50时,长度为20μm的夹杂物(初始角度90°)未能完全旋转;同时也证明相较于垂直角度,初始即倾斜的夹杂物更易发生旋转.最后,指出通过模型预估离心处理时间应以水平状态下夹杂物的上浮速度为准,并基于该结论给出了夹杂物上浮去除的大致时间.

Vision Based Hand Gesture Recognition Using 3D Shape Context

Hand gesture recognition is a popular topic in computer vision and makes human-computer interaction more flexible and convenient.The representation of hand gestures is critical for recognition.In this paper,we propose a new method to measure the similarity between hand gestures and exploit it for hand gesture recognition.The depth maps of hand gestures captured via the Kinect sensors are used in our method,where the 3D hand shapes can be segmented from the cluttered backgrounds.To extract the pattern of salient 3D shape features,we propose a new descriptor-3D Shape Context,for 3D hand gesture representation.The 3D Shape Context information of each 3D point is obtained in multiple scales because both local shape context and global shape distribution are necessary for recognition.The description of all the 3D points constructs the hand gesture representation,and hand gesture recognition is explored via dynamic time warping algorithm.Extensive experiments are conducted on multiple benchmark datasets.The experimental results verify that the proposed method is robust to noise,articulated variations,and rigid transformations.Our method outperforms state-of-the-art methods in the comparisons of accuracy and efficiency.

Survey on depth and RGB image-based 3D hand shape and pose estimation

The field of vision-based human hand three-dimensional(3D)shape and pose estimation has attracted significant attention recently owing to its key role in various applications,such as natural human computer interactions.With the availability of large-scale annotated hand datasets and the rapid developments of deep neural networks(DNNs),numerous DNN-based data-driven methods have been proposed for accurate and rapid hand shape and pose estimation.Nonetheless,the existence of complicated hand articulation,depth and scale ambiguities,occlusions,and finger similarity remain challenging.In this study,we present a comprehensive survey of state-of-the-art 3D hand shape and pose estimation approaches using RGB-D cameras.Related RGB-D cameras,hand datasets,and a performance analysis are also discussed to provide a holistic view of recent achievements.We also discuss the research potential of this rapidly growing field.

Multi-mode interaction middleware for software services

Due to the independency, variability, and tailorability of software service in the open environment, the research of middleware which supports software services multi-mode interaction is thus of great importance. In this paper, an agent-based multi-mode interaction middleware model and its supporting system for software services were proposed. This model includes an interaction feature decomposition and configuration model to enable interaction programming, an agent-based middleware model, and a programmable coordination media based on reflection technology. The decomposition and configuration model for interaction features can assist programmers in interaction programming by analyzing and synthesizing interaction features. The agent-based middleware model provides a runtime framework for service multi-mode interaction. The programmable coordination media is able to effectively support software service coordination based on multimode interaction. To verify feasibility and efficiency of the above method, the design, implementation and performance analysis of Artemis-M3C, a multi-mode interaction middleware for software services, were introduced. The result shows that the above method is feasible and that the Artemis-M3C system is practical and effective in multi-mode interaction.

Construction of a 2D Cd(II) Coordination Polymer Based on a V-shaped Bidentate Ligand

A two-dimensional（2D）coordination polymer{[Cd（bdc）（dpb）]·H2O}n（1）has been prepared by solvothermal reaction of 1,3-dipyridyl benzene（1,3-dpb）with deprotonated1,4-benzenedicarboxylate（H2bdc）,and was characterized by elemental analysis,IR spectroscopy,and X-ray single-crystal diffraction.It crystallizes in the monoclinic system,space group C2/c with a=15.1839（12）,b=20.7585（17）,c=7.2989（6）,β=117.3450（10）°,V=2043.5（3）3,C24H18N2O5Cd,Mr=526.81,Dc=1.712 g/cm3,F（000）=1056.0,μ=1.110 mm-1and Z=4.The neighboring Cd（II）ions link the bdc2-anions and 1,3-dpb to form an infinite 2D sheet,and such two2D sheets are interlocked with each other to form a 2D→2D sheet.Two groups of interlocked sheets are further linked together by intermolecularπ···πinteraction,giving a 3D supramolecular network.In addition,the fluorescence property of 1 was also studied.

Quantum transport through a Z-shaped silicene nanoribbon

In this work,the electronic transport properties of Z-shaped silicene nanoribbon（ZsSiNR） structure are investigated.The calculations are based on the tight-binding model and Green＇s function method in Landauer-Biittiker formalism,in which the electronic density of states（DOS）,transmission probability,and current-voltage characteristics of the system are calculated,numerically.It is shown that the geometry of the ZsSiNR structure can play an important role to control the electron transport through the system.It is observed that the intensity of electron localization at the edges of the ZsSiNR decreases with the increase of the spin-orbit interaction（SOI） strength.Also,the semiconductor to metallic transition occurs by increasing the SOI strength.The present theoretical results may be useful to design silicene-based devices in nanoelectronics.

Study on a W-band modified V-shaped microstrip meander-line traveling-wave tube

The study on a miniaturized, low-voltage, wide-bandwidth, high-efficiency modified V-shaped microstrip meander-line slow-wave structure is presented. This structure is evolved from the original U-shaped microstrip meander-line slow-wave structure, combining the advantages of a traditional microstrip and a rectangular helix. In this paper, simulations of the electromagnetic characteristics and the beam-wave interaction of this structure are carried out. Our study shows that when the design voltage and the current of a sheet electron beam are set to be 4700 V and 100 mA, respectively, this miniature millimeter-wave power amplifier is capable of delivering 160-W output power with a corresponding gain of 37.3 dB and a maximum interaction efficiency of 34% at 97 GHz.

整体式桥台-RC桩-土体系受力性能

为了探究整体式桥台⁃RC桩⁃土体系的力学性能,以国内某整体桥为背景,设计并制作了4个不同桩基配筋率和截面形状的整体式桥台⁃RC桩模型,并开展整体式桥台⁃RC桩⁃土相互作用低周往复荷载拟静力试验研究,主要研究RC桩配筋率与截面形状对桥台⁃RC桩⁃土体系受力性能的影响,并分析台后土抗力、桩侧土抗力、桩身应变与桩身弯矩的分布规律等。结果表明:在桥台往复位移作用下,距离台背较近处土抗力沿高度方向的分布规律会由“三角形”分布向“抛物线形”分布转变;距离台背较远处的基本呈“三角形”分布;台后土抗力会受到RC桩配筋率和截面形状的影响,提高RC桩的配筋率或采用矩形截面可增大整体式桥台⁃RC桩⁃土体系的整体性;桩身累积变形会影响桩侧土抗力的分布规律,使桩后侧土抗力减小、桩前侧土抗力增大;采用配筋率更大或矩形截面RC桩的试件更不易受累积变形的影响,桥台⁃桩基⁃土体系整体性更好;整体式桥台⁃RC桩在向河跨侧挤压前侧土体运动时,桩身应变和弯矩的分布规律与传统桩基一致;向岸坡侧挤压后侧土体运动时,桩身最大应变和弯矩出现在台底与桩顶连接处。提高RC桩配筋率或采用矩形截面RC桩可有效减小桩身应变和弯矩,改善RC桩基的受力性能。