基于中轴变换算法的室内外一体化导航路网自动生成方法     

武恩超  张恒才  吴升 《地球信息科学学报》2018,20(6):730-737

室内外一体化导航路网的快速生成与更新对面向行人的跨场景导航具有重要意义。当前研究主要关注单一场景下的导航路网构建,对于跨室内外场景的导航路网自动生成研究较少。本文基于对偶图思想与二维平面多边形中轴变换（Medial Axis Transform）算法,提出一种室内外一体化导航路网自动生成方法,并以某建筑CAD平面图及周边路网环境为基础数据进行了实例研究。结果表明：该方法能够根据原始数据的几何、拓扑、语义信息自动构建导航路网,并支持室内外跨场景的最短路径查询,在最短路径查询效率上较传统分场景寻路模型整体提升10.18%;相较单一场景下的导航路网,一体化导航路网可结合语义信息将室内及室外导航路网有机统一起来,解决跨场景寻求最优路径的问题,为最优路径规划的相关研究提供了新的思路。  相似文献   

大民屯凹陷压力场特征及其成因机制探讨   总被引：1，自引：0，他引：1  

姜建群  张占文  史建南 《地球学报》2006,27(2):157-161

异常地层压力是沉积盆地中的常见现象,其与成烃成藏关系密切。本文以欠压实带的有无、欠压实的幅度大小、持续的深度范围,将大民屯凹陷泥岩压实类型分为4种,即强烈欠压实型、欠压实型、局部欠压实型以及正常压实型。利用测井、地质和钻井资料,运用等效深度法分析了该区现今异常压力的展布特征并探讨了其成因机制。5条超压分布剖面揭示大民屯凹陷的超压体系在凹陷内分布较广泛,纵向上基本可分为上、中、下3套压力体系。①纵向上,上部即Es23段及其以上地层基本为正常压力系统;中部即Es33段为弱超压系统;下部即Es43和Es4地层为强超压系统。②横向上,超压在洼陷中心强烈发育,到斜坡和隆起带渐渐演变为正常压力。压实不均衡和生烃作用是大民屯凹陷超压发育的主要机制。  相似文献   

Scenarios of tsunami amplitudes in the north eastern coast of Sea of Marmara generated by submarine mass failure     

A. Hayir  B. Seseogullari  İ. Kilinc  A. Erturk  H.K. Cigizoglu  M.S. Kabdasli  O. Yagci  K. Day 《Coastal Engineering》2008

In this paper the tsunamis resulting from a submarine mass failure such as slides and slumps triggered by earthquakes or other environmental effects, which is settled at the bottom of the north eastern Sea of Marmara are examined in one sample region. As the solution method, one hybrid method is developed. The main objective of this method is to combine an analytical solution presenting near-field tsunami amplitudes above the submarine mass failure with a numerical solution indicating the tsunami amplitudes in the coastal regions. For this purpose, one common linear boundary between analytical and numerical solution domains is defined. Movements of Submarine Mass Failures (SMF) are modeled using one simple kinematics source model and the amplitudes of the tsunamis at the region that are closer to the landslide are computed by using the analytical method. SMF is modeled approximately from the bottom geometry, and an average depth is used. Scenarios of SMF are established depending on the velocities and thicknesses of the failure, and near-field tsunami amplitudes are obtained in the open sea during the source time. After the source times, the solutions are found in the numerical region using TELEMAC-2D software system with the mentioned boundary above. In this boundary, the output of the analytical solutions is taken as the boundary conditions or the disturbances for the numerical method. With these disturbances, the numerical method is performed and the amplitudes are calculated in the coastal area. The generation, propagation and coastal amplifications of the tsunamis are illustrated at some certain points and regions both in the open sea and near the coast line. The results have been visualized and discussed.  相似文献   

Simulation of small-amplitude frequency-dispersive transient waves by means of the mild-slope equation     

Giorgio Bellotti  Claudia Cecioni  Paolo De Girolamo 《Coastal Engineering》2008

A numerical model based on the mild-slope equation is applied to reproduce the propagation of small-amplitude transient waves. The model makes use of the Fourier Transform to convert the time-dependent hyperbolic equation into a set of elliptic equations in the frequency domain. The results of two available experimental studies on tsunamis generated by landslides are used to validate the model, which appears to be able of carefully reproducing the effects of the frequency dispersion. An example application of tsunamis propagating around the Stromboli island is also presented to show the applicability of the present approach to real life scenarios. It is finally discussed how this model could be applied as support to a tsunami early warning system.  相似文献   

海上风电基础结构研究现状及发展趋势   总被引：13，自引：1，他引：12  

黄维平  刘建军  赵战华 《海洋工程》2009,27(2):130-134

对国外海上风电机组基础结构的研究与工程应用现状进行了较为详尽地分析,重点对我国海上风电场开发建设有借鉴意义的重力式结构、单桩结构、三角架结构和导管架结构进行了分析论述.基于我国海洋工程技术水平和海上风电产业发展的动态,分析发展适合我国国情的海上风电机组基础结构的可行性及必要性,提出我国海上风电产业发展所面临的挑战.  相似文献   

基于遥感影像光谱信息的二叉决策分类树自动生成方法研究     

闫培洁  于子凡  王勇军 《测绘科学》2009,34(6)

使用决策树方法进行遥感影像分类时需要人工辅助构建决策树,这种方法存在着一旦数据变化就要人工参与重新建立决策树的缺点。针对这一问题,文中提出了依据地物类的样本训练结果,自动构建二叉决策分类树的方法。从阈值的完整性、有效性以及自动选择满足用户需求最佳的建立决策树标准等方面保证决策树的精度以及合理性等。分类结果表明,与最大似然法相比,文中提出算法分类效果良好。  相似文献   

Numerical simulations using momentum source wave-maker applied to RANS equation model   总被引：2，自引：0，他引：2  

Junwoo Choi  Sung Bum Yoon   《Coastal Engineering》2009,56(10):1043-1060

For Navier-Stokes equation model using the VOF scheme, Lin and Liu (Lin, P. and Liu, P.L.-F. (1999). Internal wave-maker for Navier-Stokes equations models. J. Waterw. Port Coast. Ocean Eng., 125 (4), 207–215.) developed an internal wave-maker method for which a mass source function of the continuity equation was used to generate target wave trains. Using this internal wave-maker method, various numerical experiments have been conducted without any problems due to waves reflected by a wave-maker. In this study, an internal wave-maker method using a momentum source function was proposed. Various numerical simulations in two and three dimensions were performed using the momentum source wave-maker applied to the RANS equation model in a CFD code, FLUENT. To verify their applicability in 2 dimensions, the computational results obtained using the momentum source wave-maker in a channel of constant depth were compared with the results obtained by using the mass source wave-maker and with the analytical solutions. And the results of the present numerical simulations of hydraulic experiments, which represent nonlinear waves on a submerged shoal and breaking waves on a plane beach, were compared with measurements. The comparisons showed good agreements between them. To see their applicability into 3-dimensional cases, the present results in a basin of constant depth were compared with the analytical solutions, and they agreed well with each other. In addition, vertical variation of longshore current was presented by using the 3-dimensional simulation results.  相似文献   

海岛风能海水淡化组合体系研究   总被引：2，自引：0，他引：2  

任典勇  施慧雄 《海洋学研究》2009,27(2):111-118

利用风能作为海水淡化的动力能源是目前较新颖的研究课题,国际上报道的还不多.根据东南沿海丰富的海岛风能资源和海岛缺淡水的现状,就如何利用洁净能源--风能和从降低海水淡化成本的角度出发,研究如何将风力发电与海水淡化装置进行组合.通过对不同功率的离网型和并网型风力发电机技术特征的分析,设计了风能发电与不同规模海水淡化装置的组合,研究表明,30 t/d以下的海水淡化装置可以利用储能电池把风能聚集起来,作为海水淡化的动力能源,大于30 t/d的海水淡化装置必需并网.该研究还以宁波市象山县高塘岛为实例,在测得该岛风能效益时间表的基础上,设计了以不同功率的离网型风力发电机与300 t/d和500 t/d的海水淡化装置相配套,并对制水成本进行了分析.研究表明,如果不计投资利息,500 t/d的海水淡化装置产水的单位成本为2.77元/t,间隙性生产(单纯的风力发电制水)产水的单位成本为1.43元/t,有望低于市政供水价格.  相似文献   

基于改进的遗传算法边坡稳定性分析方法及其应用     

何朋朋  姚磊华  汤荣贵 《地质灾害与环境保护》2007,18(1):100-104

在遗传算法和瑞典条分法的基础上,提出了对边坡临界滑裂面的搜索方法及其最小安全系数的求解方法.文中利用安全系数的倒数作为目标函数,可行域根据实际边坡的尺寸和经验给出,而且在计算过程中根据目标函数值进行调节,逐步缩小搜索空间,使搜索效率提高.算法中利用了十进制遗传算法的改进操作优体克隆操作和子体优生操作,提高了搜索的速度和精度.  相似文献   

柳州新一代天气雷达通风系统的改进及应用     

罗延斌 《气象研究与应用》2007,28(1):69-71

在柳州新一代天气雷达建设过程中,发现其通风系统存在不足及缺陷,通过分析其通风系统的设计及安装原理,提出了改进的措施,并应用到实际当中,取得了很好的效果。  相似文献