Sequential Gaussian simulation for geosystems modeling: A machine learning approach

Sequential Gaussian Simulation(SGSIM)as a stochastic method has been developed to avoid the smoothing effect produced in deterministic methods by generating various stochastic realizations.One of the main issues of this technique is,however,an intensive computation related to the inverse operation in solving the Kriging system,which significantly limits its application when several realizations need to be produced for uncertainty quantification.In this paper,a physics-informed machine learning(PIML)model is proposed to improve the computational efficiency of the SGSIM.To this end,only a small amount of data produced by SGSIM are used as the training dataset based on which the model can discover the spatial correlations between available data and unsampled points.To achieve this,the governing equations of the SGSIM algorithm are incorporated into our proposed network.The quality of realizations produced by the PIML model is compared for both 2D and 3D cases,visually and quantitatively.Furthermore,computational performance is evaluated on different grid sizes.Our results demonstrate that the proposed PIML model can reduce the computational time of SGSIM by several orders of magnitude while similar results can be produced in a matter of seconds.     

多形态崩塌智能监测系统在北京突发地质灾害监测预警工程中的应用

采用基于微纳技术(MEMS技术)的高性能三维运动姿态测量系统,主要包括三轴陀螺仪.三轴加速度计,三轴电子罗盘等运动传感器,实现多形态崩塌智能监测。     

基于空间建模的公共安全情报分析初探

空间建模及分析作为情报分析的主要技术手段之一,在欧美等国家得到了广泛实践和应用.本文在地理信息科学的主要空间模型基础上,进行了公共安全情报分析应用的研究和实践,并应用于警用地理信息系统建设中,为我国公安机关“情报信息主导警务”提供实战参考.     

21世纪逐日无缝数据立方体构建方法及逐年逐季节土地覆盖和土地利用动态制图—中国智慧遥感制图iMap （China） 1.0

粮食安全、高质量人居环境建设、生物多样性保护、星球健康等社会可持续发展目标和对地球系统的理解、模拟与管理都迫切需要多尺度、长时序、辐射和几何精度高且一致性强的遥感观测数据集和针对用户需求的、信息主题灵活的制图产品。但是由于技术和成本限制,传统的遥感卫星难以提供同时具有高空间分辨率、高时间频率和高质量的观测数据。现有的制图和反演方案多是针对于单一传感器系列,难以充分挖掘和联合利用多源异构遥感大数据的信息潜力,造成观测时段和分辨率有限、时空一致性和可比性较差。因此,遥感领域迫切需要新的技术范式。本文基于前沿的云计算、人工智能、虚拟星座、时空融合重建等技术,针对现有遥感大数据特别是国产卫星数据,提出一套智慧遥感制图(iMap)框架。该框架从用户需求出发、问题驱动,能够大大改善当前遥感数据产品难以满足农林管理、国情监测、生态环境保护、防灾减灾、城市建设等用户的多样化、高精度地表监测需求的现状。在该框架的指导下,基于亚马逊云计算(AWS)高性能、高弹性、可扩展的分布式计算资源,搭建了在线实时、自动化、无服务器、端到端的遥感大数据生产链和并行制图系统,并生产了首套21世纪中国全境逐日无缝数据立方体(SDC)及逐年逐季节土地覆盖和土地利用制图产品。逐日SDC综合利用Landsat和MODIS卫星数据构建虚拟星座,并通过多源时空数据融合重建技术研制得到无云无缝、高精度的反射率产品,作为分析就绪数据(ARD),为高精度定量遥感反演和制图打下根基。基于这一SDC,完成了逐年逐季节地表制图。逐年平均精度超过80%。在制图过程中,基于多套多层土地覆盖和土地利用分类体系,运用有限样本稳定分类理论,迁移使用全季节普适样本库,采用自动机器学习(AutoML)策略集成优化多种分类器,并结合时空一致性变化检测和后处理技术。这两套制图产品证明了本文提出的智慧遥感制图框架的可行性和有效性。未来将进一步完善和发展该框架,以开放和灵活的理念,为促进中国遥感进一步发展提供新的思路。     

EXPERIMENTS ON THE GROUP GENERALIZATIONG OF CONTOUR LINES FOR TOPOGRAPHIC MAPS

ABSTRACT

This paper analyzes the advantages and disadvantages of two technical lines for automatic group generalization of contour lines. The author suggests that it is possible to get faster and better generalization results if we simulate the intelligence of human experts in program designing, retrieve geomorphological structural information using the input data of 2-D contour lines and derive and output the generalized 2-D results directly.     

人行为计算机仿真的一种方法

根据人工神经网络的基本原理和模拟人类大脑思维的过程,提出了一种神经网络模型和思维模型系统,用于人行为的计算机仿真.神经网络模型采用Sigmoid函数.思维模型系统由感知系统、推理机、知识库、存储单元、学习训练系统、决策系统以及行为输出系统7个部分组成.采用此系统模型对普通学生的工作日日常行为进行了计算机仿真实验.实验结果达到了预期的满意效果.     

Tunnel stability analysis during construction using a neuro‐fuzzy system

This paper presents an alternative strategy to evaluate the stability of tunnels during the design and construction stages based on a hybrid system, composed by neural, neuro‐fuzzy and analytical solutions. A prototype of this system is designed using a database formed by 261 cases, 45 real and the rest synthetic. This system is capable of reproducing the displacements induced at the periphery of the tunnel before and after support installation. The stability of the excavation process is evaluated using a criterion that considers dimensionless parameters based on the shear strength of the media, the induced deformation level in the ground, the plastic radii and the advance of excavation without support. The efficiency and validity of the prototype is verified with two examples of actual tunnels, one included in the database used to train the system and the other not included. The results of both examples show a better approximation than other commonly used techniques. Copyright © 2005 John Wiley & Sons, Ltd.     

基于CAD技术的地下管线规划辅助决策平台实现

地下管线是城市基础设施的重要组成部分,是城市规划、建设、管理的重要基础。本文基于CAD技术,介绍了地下管线规划辅助决策平台的技术路线、关键技术和功能实现,实现管线规划审批的全过程管理。     

An application of artificial intelligence for rainfall-runoff modeling

This study proposes an application of two techniques of artificial intelligence (AI) for rainfall-runoff modeling: the artificial neural networks (ANN) and the evolutionary computation (EC). Two different ANN techniques, the feed forward back propagation (FFBP) and generalized regression neural network (GRNN) methods are compared with one EC method, Gene Expression Programming (GEP) which is a new evolutionary algorithm that evolves computer programs. The daily hydrometeorological data of three rainfall stations and one streamflow station for Juniata River Basin in Pennsylvania state of USA are taken into consideration in the model development. Statistical parameters such as average, standard deviation, coefficient of variation, skewness, minimum and maximum values, as well as criteria such as mean square error (MSE) and determination coefficient (R ²) are used to measure the performance of the models. The results indicate that the proposed genetic programming (GP) formulation performs quite well compared to results obtained by ANNs and is quite practical for use. It is concluded from the results that GEP can be proposed as an alternative to ANN models.     

Case-based system for slope design

A key part of slope design is the review of past examples of slopes in similar ground conditions. This paper details the development of the SlopeSafe computer program which uses case-based reasoning to formalise this process. The program, written in Visual Basic, draws on a case-base of nearly 3000 case histories of successful and failed slopes to give an indication of the likely success of a proposed slope by matching its geometry and ground conditions to the slopes held in the case-base. XML (Extensible Markup Language) has been used to store the data and a specific set of tags has been defined to provide a standard way of storing slope information. The system has been identified by practising engineers as having the potential to be a very useful design tool.