Results 71 to 80 of about 11,487 (162)

流域输沙量和输沙率的B-P人工神经网络预测

open access: yesShuitu Baochi Xuebao, 2001
提出了应用B-P人工神经网络,建立流域输沙量和最大输沙率的预测模型.以降雨量、降雨历时、洪峰流量和洪量等因子建立的李子溪流域的输沙量和最大输沙率的B-P网络预测模型效果表明拟合率达90%左右,预留检验报准率在75%以上.
彭荔红 方志山 李祚泳
doaj  

切沟侵蚀研究进展与展望

open access: yesShuitu Baochi Xuebao, 2020
切沟是重要的侵蚀类型,是小流域侵蚀泥沙的主要来源,对其发生发展的动力过程、形态特征、监测方法及预报模型进行系统分析和总结,是揭示切沟侵蚀发生动力学机制、治理切沟侵蚀、保护土地资源的前提和基础。通过系统分析、总结切沟及切沟侵蚀概念、切沟形态特征与测量方法、影响因素、发育动力过程和预报模型等相关研究进展,明晰了切沟概念,对比了不同测定方法的优劣,量化了影响切沟发育的关键因素,明确了切沟发育各子过程的动力机制,比较了典型切沟侵蚀模型的结构与主控因素,提出了切沟侵蚀亟待加强的研究内容。为理解切沟侵蚀形成 ...
张光辉
doaj  

Classification Study by Pattern Recognition on the Relationship Between the Trace Elements in Human Hair and Sex

open access: yes, 1998
通过对人发样品中22种元素含量的数据进行变量扩维及压缩筛选处理,选出了影响性别判断较显著的变量,用PlS法处理这些变量组成的数据,得到男性与女性分类清晰的二维判别图及预报模型,并根据所建立的预报模型及人发微量元素的含量判别人的性别,准确率为81%.The data of 22 trace elements concentrations in human hair samples were obtained by ICP AES and GFAAS.The variables which have ...
庄峙厦   +4 more
core  

The evaluation of disaster loss in coastal zone under different sea level rise scene simulation: A Case Study of the Yangtze River Delta Region [PDF]

open access: yes, 2014
在全球气候变化背景下导致的海平面上升、极端气候事件等现象的日趋严重,引发了多种海洋和海岸带灾害加剧,使得我国沿海城市成为各类海洋灾害的频发区,各类海洋灾害导致的经济损失也呈现递增趋势。如何准确评估海平面上升导致的海岸带地区灾害损失,是海岸带地区制定防灾减灾和可持续发展战略的基础。本研究以长三角地区为研究区域,采用双嵌套网格风暴潮-天文潮耦合数值预报模型(NestedCoupledTide-surgePredictionModel,简称NCTSM模型)、地理信息系统 ...
林琛琛
core  

Visualization analysis of research literature on early warning of geo-hazards based on meteorological factors in the past 20 years [PDF]

open access: yes
Early warning of geo-hazards based on meteorological factors in China began in 2003, and early warning informations are issued to the public every year during the flood season to alert the public to guard against geo-hazards such as landslides, debris ...
Chunli CHEN   +5 more
core   +1 more source

Preliminary establishment of large yellow croak disease diagnosis and pre-warning system [PDF]

open access: yes, 2013
大黄鱼(Larimichthyscrocea,Richardson,1846)是中国近海特有的主要经济鱼类和当前最主要的海水养殖鱼类之一,也是中国八大优势出口水产品之一。目前全国年育苗量近20亿尾,养殖产量超过7万吨,直接产值超过30亿元。但是,近年来随着鱼用抗生素等药物的滥用,养殖密度的提高,水域生态环境日益恶化,各种大黄鱼疾病频繁爆发。病害问题给大黄鱼养殖产业带来了巨大的经济损失。因此,如何有效的防治大黄鱼疾病的爆发,对该产业可持续健康发展具有重大的意义 ...
蔡晓鹏
core  

Study on rainfall threshold of different lithologic landslides in Bailong River Basin of Gansu Province [PDF]

open access: yes
The research results regarding the threshold values for slope disasters caused by rainfall are crucial for geological disaster prevention. In this study,landslides induced by long-term heavy rainfall occurred in five counties within the Gansu section of ...
Guan CHEN   +6 more
core   +1 more source

A multifactor coupled rarly-warning model for pipeline landslide hazards based on the dynamic evolutionary process of disaster [PDF]

open access: yes
Long oil and gas pipelines inevitably cross mountainous regions with complex geological environment and are threatened by various geological disasters, the most severe of which is landslides.
Dexu QI   +5 more
core   +1 more source

基于泛化地震样本训练的全卷积神经网络在2016年熊本MW6.2地震监测中的应用

open access: yesDizhen xuebao
针对近期提出的通用全卷积神经网络模型,以2016年日本熊本MW6.2地震序列为例,验证其预警时效性、定位精度和跨震级泛化性能。通过选取震源主要影响区域作为监测范围,并向模型输入12个台站的波形数据,成功实现了震后1小时179次余震序列中69次余震的定位。结果表明:通用全卷积神经网络模型无需迁移学习即可在P波抵达首个台站后的4.4—6.4 s发布警报,并提供可靠的震源参数(震中均方根误差为3.409 km,深度均方根误差为3.787 km),展现出优异的泛化能力与实用性 ...
Bifu Wei, Xiong Zhang, Yu Yang
doaj   +1 more source

The Mechanism of Stability and Dynamic Process of RMB Exchange Rate(Ⅰ) Modelling [PDF]

open access: yes, 1999
根据现阶段我国外汇管理体制和汇率政策的基本特征,应用汇率经济学理论与系统分析方法,探讨国内外汇市场供求变化的经济学原理,力图揭示汇率稳定与外汇储备变化的内在机制.在描述外汇储备变化与进出口及外资净流入之间关系的基础上,以汇率预期为中间变量,研究人民币汇率与外资净流入及国际外汇市场的汇率走势之间的内在联系,进而建立人民币汇率的实证分析模型.This paper attempts to construct a theoretical model that can be used to investigate
魏巍贤
core  

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