Three-Dimensional Tidal Model and Its Application to Numerical Simulation of Water Quality in Coastal Waters

The turbulence mechanism plays an important part in the mixing process and momentum transfer of turbulence. A three-dimensional Prandtl mixing length tidal model has been developed to simulate tidal flows and water quality. The eddy viscosities and diffusivities are computed from the Prandtl mixing length model. In order to model the water quality of an estuary or coastal area many interdependent processes need to be simulated. These may be conveniently separated into three main groups: transport and mixing processes, biochemical interaction of water quality variables and the utilization and re-cycling of nutrients by living matter. The model simulates full oxygen and nutrient balance, primary productivity and the transport, reaction mechanism and fate of pollutants over tidal time-scales. The model is applied to numerical simulation of tidal flows and water quality in Dalian Bay. The model has been calibrated against a limited data set of historical water quality observations and in general demonstrates excellent agreement with all available data.

The three-dimension model for the rock-breaking mechanism of disc cutter andanalysis of rock-breaking forces

To study the rock deformation with three- dimensional model under rolling forces of disc cutter, by car- rying out the circular-grooving test with disc cutter rolling around on the rock, the rock mechanical behavior under rolling disc cutter is studied, the mechanical model of disc cutter rolling around the groove is established, and the the- ory of single-point and double-angle variables is proposed. Based on this theory, the physics equations and geometric equations of rock mechanical behavior under disc cutters of tunnel boring machine （TBM） are studied, and then the bal- ance equations of interactive forces between disc cutter and rock are established. Accordingly, formulas about normal force, rolling force and side force of a disc cutter are de- rived, and their validity is studied by tests. Therefore, a new method and theory is proposed to study rock- breaking mech- anism of disc cutters.

Modeling of Irregular Structures in Scene Simulation Based on Creator and 3dsmax

Creating proper 3D models plays an important pole in the development of scene simulation system based on multigen creator and Vega software. However, it is very difficult to construct complex structures by multigen creator. In this paper, an approach is proposed which is utilizing 3dsmax as assistant modeling software. 3D models developed in 3dsmax could be saved in 3ds format and then imported into multigen creator software. The models are revised and then saved in fit format by creator. For reducing model＇s data, simplification strategy is proposed. The problem of constructing complex models in creator is solved smoothly. In the development of digital rocket simulation project, the models constructed by this method have good visual effect, small size, and could be driven by Vega correctly.

Terrain Simplification Research in Augmented Scene Modeling

Augmented reality is the merging of synthetic sensory information into a user's perception of a real environment. As one of the most important tasks in augmented scene modeling, terrain simplification research has gained more and more attention. In this paper, we mainly focus on point selection problem in terrain simplification using triangulated irregular network. Based on the analysis and comparison of traditional importance measures for each input point, we put forward a new importance measure based on local entropy. The results demonstrate that the local entropy criterion has a better performance than any traditional methods. In addition, it can effectively conquer the 'short-sight' problem associated with the traditional methods.

Structured scene modeling using micro stereo vision system with large field of view

This paper presents a method for structured scene modeling using micro stereo vision system with large field of view. The proposed algorithm includes edge detection with Canny detector, line fitting with principle axis based approach, finding corresponding lines using feature based matching method, and 3D line depth computation.

Three-Dimensional Scenes Restore Using Digital Image

Encryption and decryption method of three-dimensional objects uses holograms computer-generated and suggests encoding stage. Information obtained amplitude and phase of a three-dimensional object using mathematically stage transforms overlap stored on a digital computer. Different three-dimensional images restore and develop the system for the expansion of the three-dimensional scenes and camera movement parameters. This article talks about these kinds of digital image processing algorithms as the reconstruction of three-dimensional model of the scene. In the present state, many such algorithms need to be improved in this paper proposing one of the options to improve the accuracy of such reconstruction.

A modeling method for virtual scene based on multi-view image sequence

Through the analysis and comparison of shortcomings and advantages of existing technologies on object modeling in 3D applications,we propose a new modeling method for virtual scene based on multi-view image sequence to model irregular objects efficiently in 3D application.In 3D scene,this method can get better visual effect by tracking the viewer's real-time perspective position and projecting the photos from different perspectives dynamically.The philosophy of design,the steps of development and some other relevant topics are discussed in details,and the validity of the algorithm is analyzed.The results demonstrate that this method represents more superiority on simulating irregular objects by applying it to the modeling of virtual museum.

Three-dimensional frequency-domain full waveform inversion based on the nearly-analytic discrete method

The nearly analytic discrete(NAD)method is a kind of finite difference method with advantages of high accuracy and stability.Previous studies have investigated the NAD method for simulating wave propagation in the time-domain.This study applies the NAD method to solving three-dimensional(3D)acoustic wave equations in the frequency-domain.This forward modeling approach is then used as the“engine”for implementing 3D frequency-domain full waveform inversion(FWI).In the numerical modeling experiments,synthetic examples are first given to show the superiority of the NAD method in forward modeling compared with traditional finite difference methods.Synthetic 3D frequency-domain FWI experiments are then carried out to examine the effectiveness of the proposed methods.The inversion results show that the NAD method is more suitable than traditional methods,in terms of computational cost and stability,for 3D frequency-domain FWI,and represents an effective approach for inversion of subsurface model structures.

Physically based modeling and animation of tornado

Realistic modeling and rendering of dynamic tornado scene is recognized as a challenging task for researchers of computer graphics. In this paper a new physically based method for simulating and animating tornado scene is presented. We first propose a Two-Fluid model based on the physical theory of tornado, then we simulate the flow of tornado and its interaction with surrounding objects such as debris, etc. Taking the scattering and absorption of light by the participating media into account, the illumination effects of the tornado scene can be generated realistically. With the support of graphics hardware, various kinds of dynamic tornado scenes can be rendered at interactive rates.

Research on Motion Attention Fusion Model-Based Video Target Detection and Extraction of Global Motion Scene

For target detection algorithm under global motion scene, this paper suggests a target detection algorithm based on motion attention fusion model. Firstly, the motion vector field is pre-processed by accumulation and median filter;Then, according to the temporal and spatial character of motion vector, the attention fusion model is defined, which is used to detect moving target;Lastly, the edge of video moving target is made exactly by morphologic operation and edge tracking algorithm. The experimental results of different global motion video sequences show the proposed algorithm has a better veracity and speedup than other algorithm.

面向水库型小流域的多源水利三维建模方法研究

针对大型河道三维可视化建模中采用激光雷达、声呐等传感器获取水下地形建模方式操作复杂且成本较高的缺陷,在利用基础测绘成果构建实景地形模型的基础上,采用多源三维模型融合方法对月塘水库小流域进行实景建模。首先采用倾斜摄影三维建模技术对重点水利工程进行实景建模,并利用专业建模软件对重要控制单元进行构件级建模;然后利用已有河道断面数据结合河流面状矢量数据,实现流域内胥浦河河道实景三维建模;最后通过人机交互方式对多源实景模型进行微调与相互印证,实现月塘水库小流域多源三维模型精准融合构建。研究成果可为河道型水库的预报调度与洪水风险分析提供可视化模型基础与决策支撑。

短视频商业模式下网红特质对用户产品依恋的影响研究——基于实验研究与仿真分析的方法

伴随着短视频商业模式的发展,短视频网红特质已经成为推动用户形成产品依恋的重要因素,但目前鲜有研究对其中的实现路径与机理进行深入探究。本文基于信号理论,构建短视频商业模式下网红特质对用户产品依恋的影响模型,同时综合运用实验研究与系统动力学仿真的方法对模型进行检验。结果表明:(1)短视频网红特质对用户产品依恋具有促进作用;(2)信任感知在短视频网红特质与用户产品依恋之间起中介作用;(3)生活场景还原不仅调节短视频网红特质对用户产品依恋的影响,而且在短视频网红特质、信任感知和用户产品依恋的中介关系中起调节作用;(4)系统动力学仿真结果表明,短视频网红特质对用户产品依恋的影响是一个长期累积的过程,并且随着时间的推移,这种影响效果愈发显著。研究结果为相关企业的短视频商业模式实践提供了有益的启示和参考。

基于可调场景语义标注范围的家庭室内语义地图构建

针对家庭室内环境语义地图建图速度较慢和在门口场景语义标注易出现错误等问题,提出一种基于可调场景语义标注范围的家庭室内语义地图构建方法。首先根据YOLOv5s识别的物体大小赋予相应的场景置信度,基于该场景置信度设置阈值使得语义标注范围限制在机器人当前所在区域,确保场景切换时语义标注范围不会立即改变。然后基于人工势场虚拟力“引力斥力”原理,实现语义标注范围的扩大或缩小。最后结合阈值和动态语义标注范围,避免在门口场景中出现语义标注错误。实验结果表明:与Places205-VGG16神经网络建立家庭室内语义地图相比,所提方法平均效率和平均精准率分别提升了11.0%和7.8%,在家庭室内环境中具有一定的优越性。

基于关键视图的文本驱动3D场景编辑方法

基于去噪扩散模型的零样本图像编辑方法取得了瞩目的成就,将之应用于3D场景编辑可实现零样本的文本驱动3D场景编辑。然而,其3D编辑效果容易受扩散模型的3D连续性与过度编辑等问题影响,产生错误的编辑结果。针对这些问题,提出了一种新的文本驱动3D编辑方法,该方法从数据端着手,提出了基于关键视图的数据迭代方法与基于像素点的异常数据掩码模块。关键视图数据可以引导一个3D区域的编辑以减少3D不一致数据的影响,而数据掩码模块则可以过滤掉2D输入数据中的异常点。使用该方法,可以实现生动的照片级文本驱动3D场景编辑效果。实验证明,相较于一些目前先进的文本驱动3D场景编辑方法,可以大大减少3D场景中错误的编辑,实现更加生动的、更具真实感的3D编辑效果。此外,使用该方法生成的编辑结果更具多样性、编辑效率也更高。

基于双尺度海谱的动态海面场景仿真建模分析

针对典型复杂环境下动态海面目标场景,采用双尺度海谱用于风驱海面的建模构建公里级别复杂场景电磁仿真模型,研究面向体-面复合结构的自适应弹跳射线法,结合区域分解和并行加速技术实现典型目标及地物环境的耦合电磁散射特性分析,形成公里级别复杂场景多维复合散射特性仿真能力,实现大场景复杂环境与目标一体化模型的高效电磁散射计算与分析。通过测量海面邮轮在实际海面背景下的电磁散射特性,进行验证,为复杂海面背景下大尺度目标的动态场景生成和目标特性研究提供重要支撑作用。

基于倾斜摄影的多回输电线路实景三维模型构建系统设计

为了使改进多回输电线路三维模型更加符合实际情况,该文将倾斜摄影技术引入多回输电线路实景三维模型构建系统中,提升数据获取的精准性。硬件方面,微处理器作为指令核心处理结构,负责读取并解析指令;设计多回输电线路数据采集模块和EP3SE110F1152C4数据存储器,并利用数据存储器对系统运行过程中的多项数据进行存储;软件方面,借助倾斜摄影技术,获取多回输电线路数据,并计算其对应的比例尺和航高,再对获取的数据进行优化,消除数据中的误差,并对其进行配准处理和特征匹配以及纹理映射和归一化处理,由此完成对多回输电线路实景三维模型的构建。经过实验验证,和以往的多回输电线路实景三维模型构建系统相比,设计的基于倾斜摄影的多回输电线路实景三维模型构建系统在实际应用中模型构建完整度为95.6%,构建效果更好。

重大节假日出行方式选择模型研究

为优化节假日高速公路免费政策,选取出行者变量、出行方式相关变量和行程特性变量作为效用变量,构建了出行方式位于上层、出行距离位于下层的NL模型。利用弧弹性法分析不同收费标准和收费里程条件下出行者的行为特性,并利用场景仿真评价多种收费组合对出行方式的影响。研究结果表明:提高收费标准,汽车出行比例会显著降低,且高速铁路承担了大部分的转移交通量。随着收费里程的增加,出行者逐渐倾向于出行成本较小的普通铁路。对长距离出行收费可以提升公共交通分担率,缓解节假日高速公路的交通拥堵。

基于改进YOLOv8的露天矿区行车障碍物检测

露天矿区场景复杂,行车障碍物检测受扬尘和颗粒物等粉尘噪声干扰严重,难以准确识别障碍物,尤其是光线较差的夜间,不利于做出正确决策,从而影响无人作业的安全性和整体效率。针对以上问题,提出了一种基于YOLOv8n模型的露天矿区行车障碍物检测算法YOLOv8n-Enhanced。该算法主要从3个方面进行了改进,具体包括:首先,针对受粉尘噪声干扰严重和夜间光线不足的问题,提出了C2fCA模块结构,提高了模型特征提取能力;其次,使用轻量级卷积技术GSConv和VoV-GSCSP模块,减轻模型复杂性,实现检测器更高的计算成本效益;最后,使用WIOU损失函数,提高了模型泛化能力。试验结果表明:改进算法在保持实时性的前提下,可将YOLOv8n的平均精度(mean Average Precision,mAP)分别提高1.8%和2.6%,实现白天与夜间场景下不同尺度的障碍物识别。

实时VR场景下多尺度数字全息成像仿真

在数字全息成像的过程中,受光电传感器件结构参量、光照强度以及传输方向等因素的影响,导致全息图成像的亮度、分辨率降低。为了提高多尺度数字全息成像的真实度,提出了实时VR场景下多尺度数字全息成像方法。通过定义图像像素点分布的概率函数,计算多尺度数字图像像素的显著性,根据图像像素特征的分布方差,提取出多尺度数字图像像素点。利用小波变换系数识别多尺度数字图像的噪声,基于图像噪声信号的方差分布,精细化处理多尺度数字图像,结合小波反变换,构建多尺度数字图像去噪模型,得到去噪后的图像。根据多尺度数字全息成像模型,得到图像增强的梯度场,在实时VR场景下,引入加权融合的方法,得到图像的高频细节分量,利用图像融合规则,生成多尺度数字图像。实验结果表明,所提方法能够生成VR图像,并将成像真实度和清晰度分别提高到90%以上和92%以上。

基于注意力网络尺度特征融合的遥感场景分类

针对遥感数据集存在的类内差异性大和类间相似性高的特点导致遥感场景分类准确率不高的问题,提出了一种基于注意力网络尺度特征融合(MSA-CNN)的遥感影像场景分类模型.将遥感图像经过尺度变换操作输入到VGG-16网络提取遥感影像的多尺度特征,使用多选框注意力模型(MS-APN)提取图像多尺度下的目标区域,对目标区域进行剪切和放大并输入到三层网络结构中.融合原始影像的多尺度特征和目标区域的特征,并且利用LBP对全局特征表达,克服遥感图像因拍摄角度不同带来的差异性.将融合的多尺度特征输入到网络全连接层来完成最终的分类预测任务.实验结果显示:MSA-CNN平均分类精度较注意循环卷积网络(ARCNet)和传统细粒度循环注意力网络(RA-CNN)在NWPU-RESISC45公开数据集上分别提升1.63%和2.66%,在UC Merced Land-Use公开数据集上较RA-CNN提升0.64%.结果表明:提出的MSA-CNN能够有效提高遥感图像场景分类的准确率.