与二维电子地图互响应的虚拟三维场景生成

该文详细介绍了与二维电子地图互响应的虚拟三维场景中地形、地物的生成及场景组织等关键技术的解决方案。地形的生成是采用少量的可描述地形总体形状的DEM数据构建地形的总体框架,并应用分形技术来生成地形细部的方法。对与视点相近的树木用L系统分形生成,并将生成的描述树木的数据保存起来,以便在实时刷新时调用;与视点较远的树木用贴图的方法来表现。介绍了采用模块化与纹理贴图技术来简化桥梁生成的具体实现技术,从而减少桥梁描述的数据量。对实现互响应功能时需解决的视点位置确定问题给出了具体的解决方法。这些生成方法有效地减少了三维场景实时生成的延迟性,并保证了实时互响应的实现。

基于VRML的虚拟社区与二维地图互响应的研究

虚拟现实技术已经应用于社会生活的各个方面,使用VRML创建的三维虚拟社区给用户以身临其境的真实感,同时也容易产生不知其方向和位置的迷失感。为此提出了一个对应三维虚拟社区的二维电子地图与虚拟社区间相互响应的思想来减少用户在虚拟社区中的迷失感的方法,利用VRML与Java的通信机制实现用户在三维虚拟社区与二维电子地图的相互响应,让用户在虚拟社区中漫游时,二维电子地图实时显示出相应的位置。在二维电子地图中用户改变位置时,相应地在虚拟社区中视点跳到对应的位置。

二维与三维信息互响应技术研究

本文研究的互响应思想有效地解决了当今独立的二维电子地图和三维虚拟场景各自不足之处,做到了两者间的优势互补。本文还对二维电子地图和三维虚拟场景中的可视化以及互响应后的可视化问题进行了探讨,最后在VC++平台和Vega函数库下实现了二维和三维信息表现的融合与互响应。

二维GIS与三维场景仿真互响应技术在灌区管理系统中的应用

介绍了二维GIS和三维场景仿真各自优缺点,提出通过互响应技术结合两者优点的方法,克服了二维地图的抽象多义性和三维场景仿真的漫游迷失性。并以灌区管理系统为例,提出了二维三维交互在灌区管理当中的具体应用与实现。

信息互响应技术研究

随着计算机技术、仿真技术及虚拟现实技术的快速发展,给二维电子地图注入了新的活力,三维电子地图正成为电子地图发展的一个重要方向。本文研究的互响应思想有效地解决了当今独立的二维电子地图和三维虚拟场景各自不足之处,做到了两者间的优势互补。文章还对二维电子地图和三维虚拟场景中的可视化以及互响应后的可视化问题进行了探讨。最后在VC++平台和Vega函数库下实现了二维和三维信息表现的融合与互响应。

二维与三维信息互响应技术研究

随着计算机技术、仿真技术及虚拟现实技术的快速发展,给二维电子地图注入了新的活力,三维电子地图正成为电子地图发展的一个重要方向。本文研究的互响应思想有效地解决了当今独立的二维电子地图和三维虚拟场景各自不足之处,做到了两者间的优势互补。本文还对二维电子地图和三维虚拟场景中的可视化以及互响应后的可视化问题进行了探讨。最后在VC++平台和Vega函数库下实现了二维和三维信息表现的融合与互响应。

一种利用车激桥梁响应的互相关函数识别桥梁损伤的方法

提出一种利用车激桥梁响应互相关函数灵敏度识别桥梁损伤的方法,通过记录设置在桥梁上的两个测点的加速度响应,比较桥梁损伤前后两点响应的互相关函数的变化值,使用灵敏度方法来识别桥梁损伤.通过算例对桥梁损伤进行了识别,并与使用响应灵敏度方法得到的识别结果进行了对比.结果表明,使用互相关函数灵敏度方法可以提高识别结果的准确性,而且计算较简单,收敛速度较快,同时能够很大程度地抑制测点的高水平噪声,对桥梁多单元损伤也有较好的识别结果.

二维GIS与三维场景交互技术的研究与应用

介绍了二维GIS和三维场景仿真各自优缺点,提出了通过互响应技术结合两者优点的方法以克服各自的局限性,以灌区信息管理系统为例,实现了二维GIS和三维场景交互技术的具体应用。

Zonal Coupling Analysis Method of Seismic Response of Offshore Monopile Wind Turbine

The seismic safety of offshore wind turbines is an important issue that needs to be solved urgently.Based on a unified computing framework,this paper develops a set of seawater-seabed-wind turbine zoning coupling analysis methods.A 5 MW wind turbine and a site analysis model are established,and a seismic wave is selected to analyze the changes in the seismic response of offshore monopile wind turbines under the change of seawater depth,seabed wave velocity and seismic wave incidence angle.The analysis results show that when the seawater increases to a certain depth,the seismic response of the wind turbine increases.The shear wave velocity of the seabed affects the bending moment and displacement at the bottom of the tower.When the angle of incidence increases,the vertical displacement and the acceleration of the top of the tower increase in varying degrees.

三维虚拟场景在车辆导航系统中的应用

城市道路交通网络的日益复杂,使得现有的二维电子地图无法直观的反映道路之间的交错关系,基于二维电子地图的车辆导航系统在复杂的道路交叉口的路径引导也显得无能为力。提出建立复杂道路口的三维虚拟场景和实现场景的指定路径漫游,并以立交桥为例在VC++6.0中实现二维电子地图与三维虚拟场景的互响应,充分结合二维电子地图在车辆导航过程中的整体性、宏观性与局部三维虚拟场景的直观易懂性等优点,提高现有的车辆导航系统的路径引导效率。

基于虚拟环境的黄河仿真系统构建

虚拟现实的产生和发展无疑为加强地理科学研究提供了强大的手段和方法上的支持。本文从虚拟环境的角度出发,给出了一个黄河仿真系统的建设方案,它包括数据源、三维仿真地形库、三维仿真模型库、三维仿真虚拟实现四大模块。然后详细探讨了黄河仿真系统的关键技术:①通过对三维图形开发工具OpenGL的原理、实现功能等的分析,提出了在黄河仿真系统建设中OpenGL技术的具体应用实现方法,实现了实时动态漫游;②基于MultiGenCreator的真实感三维模型建设;③利用OpenGL和MO来实现三维场景与二维电子地图的互响应;这充分发挥了三维场景与二维电子地图各自的优势,有机地结合了三维虚拟场景的直观性、现实性、局部性和二维电子地图的宏观性、整体性、简洁性的优点,同时又克服了三维虚拟场景漫游的方向迷失感和二维电子地图的抽象多义性。

多机协作在数字校园系统中的应用

在传统的单机数字校园的基础上,引入了多机协作的概念。该系统利用良好的局域网环境,在网络互联的多台计算机上通过网络数据传输协议实现单机操作、多机协作、多屏显示。多机协作克服了在单机系统中因为拆分或切换窗口所造成的可视范围缩小和不太直观的问题。本文系统地阐述了多机协作的优点、应用领域、体系结构、功能划分、区域分布、数据传输协议等问题。

Seismic Response of a Structure under Various Subsoi Models

Three types of the soil-structure interaction are used for structure analysis loaded by seismic effects. An example of the real RC building is used to demonstrate differences in the dynamic response results in the calculation of internal forces and displacements. Variant three options of the soil models were used as a building supporting structure. In the case of soil model A, the soil was modelled by using of equivalent stiffness values, stemming from the theory of a rigid circular disc on an elastic homogeneous half-space. Non-uniformly modelled vertical stiffness of the soil according to the Boussinesq model was used for model B. Both models A and B are characterised by the ＂averaged＂ soil model on the bases of spring constants. Model C was used for the soil better corresponding to its actual composition by the Winkler-Pasternak theory. Model C, where the actual layered soil is considered, is modelled more accurately than for the ＂averaged＂ soil of models A and B. The dynamic response of models operating with ＂averaged＂ values of rigid and soft soil layers is markedly shifted to the conservative smaller values of internal forces. The building response tbr model C in dynamic displacements is significantly higher than for the both models A and B.

A simplified model to predict blast response of CFST columns

In order to study the dynamic response of concrete-filled steel tube(CFST) columns against blast loads,a simplified model is established utilizing the equivalent single-degree-of-freedom(SDOF) method,which considers the non-uniform distribution of blast loads on real column and the axial load-bending moment(P-M) interaction of CFST columns.Results of the SDOF analysis compare well with the experimental data reported in open literature and the values from finite element modeling(FEM) using the program LS-DYNA.Further comparisons between the results of SDOF and FEM analysis show that the proposed model is effective to predict the dynamic response of CFST columns with different blast conditions and column details.Also,it is found that the maximum responses of the columns are overestimated when ignoring the non-uniformity of blast loads,and that neglecting the effect of P-M interaction underestimates the maximum response of the columns with large axial load ratio against close range blast.The proposed SDOF model can be used in the design of the blast-loaded CFST columns.

Agent-Based Simulation for Interconnection-Scale Renewable Integration and Demand Response Studies

This paper collects and synthesizes the technical requirements, implementation, and validation methods for quasi-steady agent-based simulations of interconnectionscale models with particular attention to the integration of renewable generation and controllable loads. Approaches for modeling aggregated controllable loads are presented and placed in the same control and economic modeling framework as generation resources for interconnection planning studies. Model performance is examined with system parameters that are typical for an interconnection approximately the size of the Western Electricity Coordinating Council(WECC) and a control area about 1/100 the size of the system. These results are used to demonstrate and validate the methods presented.

Dynamic interaction analysis and pairing evaluation in control configuration design

This paper presents some new dynamic interaction analysis approaches for square or non-square systems and a pairing evaluation method. For square stable systems, an open-loop approach is proposed, which features the tradeoff between the contributions of response time constant and delay time to relative gain. For non-square stable systems, an extension from the proposed open-loop approach for square systems is presented and the corresponding pairing procedure is given. No interaction analysis approach is perfect for all systems, so any recommended pairing needs to be examined. An evaluation method is proposed in closed-loop with optimal controllers for each loop and whether the pairing is appropriate can be evaluated through testing if the equivalent relative gain is within defined scope. The advantages and effectiveness of proposed interaction analysis approaches and pairing evaluation method are highlighted via several examples of industrial processes.

Comparative Analysis of Seismic Response Characteristics of Pile-Soil-Stnicture Interaction System

The study on the earthquake-resistant performance of a pile-soil-structure interaction system is a relatively complicated and primarily important issue in civil engineering practice. In this paper, a computational model and computation procedures for pile-supported structures, which can duly consider the pile-soil interaction effect, arc established by the finite clement method. Numerical implementation is made in the time domain. A simplified approximation for the seismic response analysis of pile-soil-structure systems is briefly presented. Then a comparative study is performed for an engineering example with numerical results computed respectively by the finite clement method and the simplified method. Through comparative analysis, it is shown that the results obtained by the simplified method well agree with those achieved by the finite element method. The numerical results and findings will offer instructive guidelines for earthquake-resistant analysis and design of pile-supported structures.

Numerical Simulation for Progressive Collapse of Continuous Girder Bridge Subjected to Ship Impact

The three-stage simulation method based on LS-DYNA was introduced in this study to simulate the progressive collapse of a continuous girder bridge after a ship-bridge collision. The pile-soil dynamic interaction and the initial stress and deformation of the whole bridge before the collision were considered. By analyzing the damage, deformation, stress distribution and collapse process of the whole bridge, the results show that the displacement response of the cap beam lags behind the pile cap. The response order of the whole bridge's components depends on their distances from the collision region. The plastic deformation of soil around piles has a positive effect on delaying the further increase in the displacement of piles. The impacted pier's losing stability and its superstructure's excessive deformation are the main reasons leading to the progressive collapse of the continuous girder bridge.

The Internet and its Psychological and Social Effects on the UAEs Youth

The subject of this research concentrate on indicating psychological and social effects for the Internet on students in Sharjah University/Communication College/in other words the researcher try to know students opinion and impressions regarding the use of Internet and effect of the same, as well as opinion of positive and negative benefits regarding Internet, especially for the university＇s students who use Internet repeatedly in their daily routine. This stage marked by facts and characteristics based on search for information, explore the students world, and their expectations for that science. This study is the first in its kind in United Arab Emirates that try to shed light on the social and psychological effects of the lnternet, therefore we pave the way in front of those who administer lnternet and indicate to them guidelines for that to allow decisions maker to be aware about the world around university＇s student, the world that enjoy less interest for use of Internet at university, and what is the social and psychological effects of the use of Internet. And the study allow providing information and data that several sectors in society need. It draws clear image for the use of Internet at university by the student and whatever social and psychological effects that happened as a result of that use, so it consider as a survey for whom desire to know such information in United Arab Emirates.

Influence of Structure Plane Size on Seismic Response of Soil-Structure Interaction

The influence of the change of structure plane size on seismic response was studied for a soil-structure interaction system.Based on the finite element method,a soil-structure interaction calculation model was established to analyze the seismic response by changing the structure plane size and choosing different earthquake waves for different soil fields.The results show that when the natural periods of vibration for different structure plane sizes are close,under the same earthquake wave,the total displacement on the top layer of the structure and the foundation rotation displacement decrease with the increase of structure plane size,and the proportion of superstructure elastic selfdeformation displacement to the total displacement increases with the increase of structure plane size.While for different types of sites and seismic waves,under the horizontal and vertical seismic waves,the seismic responses of different plane sizes have a similar change rule.