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1.
介绍了基于STC89C516RD＋单片机的实验开发平台的硬件电路设计、ISP编程、软件开发实例及系统的抗干扰措施.为帮助学生学习单片机技术,同时也为有经验者开发和调试产品打下基础. 相似文献
2.
不透水面是衡量城市化程度的重要指标之一,对京津唐城市群的不透水面进行深入研究,可以量化城市群扩张过程及其影响,对该区域多城市协调发展及规划布局具有重要意义。本文结合高分辨遥感影像、生长季及落叶季的Landsat TM遥感影像和夜间灯光数据等,采用分类和回归树（Classification and rRegression Tree, CART）算法,构建了适于京津唐地区不透水面盖度提取的技术方案,获取了京津唐地区1995-2016年共5期地表不透水面盖度专题信息,并分析了地表不透水面的时空演变规律,结论为：① 适于京津唐地区不透水面盖度提取的CART算法的最佳输入变量组合为：生长季和落叶季的Landsat TM图像以及对应的夜间灯光数据;其次为生长季Landsat TM遥感图像和夜间灯光数据组合方案。利用该组合方案,ISP估算输出结果的交叉验证精度R值可以达到约0.85,可以满足地表不透水面纵向对比分析的需要。② 从地表不透水面总面积数量值来看,1995-2016年京津唐主体城市区域整体上呈增长趋势,其中2011-2016年地表不透水面积增加愈加明显;③ 从地表不透水面盖度值的高低来看,1995-2016年京津唐中、高盖度不透水面的占比都是在不断增长的,低盖度不透水面占比存在少量下降现象,且京、津、唐3城市的主体城区各阶段变化差异较大,反映出了各城市扩张具有各自不同的时空演变特征。 相似文献
3.
基于QuickBird高分辨率影像、LandsatTM影像及夜间灯光数据,设计了集成CART（Classification and Regression Tree,）算法和多源遥感数据估算亚像元级不透水地表盖度的技术方案,采取适用于典型温带半干旱地区的ISP（Impervious Surface Percentage ）提取方法,提取2001年和2011年北京城区不透水地表盖度,并将不透水地表盖度分为3类,ISP为10%~60%的区域为低密度区,60%~80%的区域为中密度区,大于80%的区域为高密度区。同时采用单窗算法反演2001年和2011年地表温度,对2001-2011年北京六环以内城区不同环路区域ISP发展趋势,以及其与地表温度的相关性进行分析。结果表明：（1）北京城区的不透水地表盖度变化主要集中在低密度区域,与之相比,中密度区域和高密度区域不透水地表盖度变化不大。2001-2011年来北京五环以内区域由于城建区较多,整体不透水地表变化并不明显,主要变化区域集中在五环至六环以内区域,其中低密度区增长明显,中密度区和高密度区主要增长集中在东部,可以看出,近年来五环至六环以内区域发展迅速,城建区范围不断扩大。（2）相较于2001年,2011年北京市中心地表温度明显上升,高温区聚集程度更为明显。其中四环以内地表温度与周边区域地表温度相比,温差明显增大。（3）通过对比2001年和2011年各密度区平均地表温度发现,相较于2001年,2011年北京市六环以内城区各密度区之间的地表温度差异更大,城市热岛效应更为明显。（4）2001年和2011年北京城区各环路区域内不透水地表盖度与地表温度均呈正相关。四环至六环区域,地表温度随不透水地表盖度变化的趋势相近。ISP在10%~20%的区域,地表温度随不透水地表盖度增高而上升的速率明显高于其他区域,ISP大于20%的区域地表温度上升速率下降,且趋于一致。 相似文献
4.
Return periods calculated for different environmental conditions are key parameters for ocean platform design.Many codes for offshore structure design give no consideration about the correlativity among multi-loads and over-estimate design values.This frequently leads to not only higher investment but also distortion of structural reliability analysis.The definition of design return period in existing codes and industry criteria in China are summarized.Then joint return periods of different ocean environmental parameters are determined from the view of service term and danger risk.Based on a bivariate equivalent maximum entropy distribution,joint design parameters are estimated for the concomitant wave height and wind speed at a site in the Bohai Sea.The calculated results show that even if the return period of each environmental factor,such as wave height or wind speed,is small,their combinations can lead to larger joint return periods.Proper design criteria for joint return period associated with concomitant environmental conditions will reduce structural size and lead to lower investment of ocean platforms for the exploitation of marginal oil field. 相似文献
5.
基于遥感的城市热环境研究通常通过分析植被、不透水面和地表温度（Land Surface Temperature, LST ）的关系来进行。虽然植被的降温作用和不透水面的增温作用已受到普遍认可,但缺少针对降温和增温效率的定量研究,本研究采用地表降温率（Land Surface Cooling Rate, LSCR）和地表增温率（Land Surface Warming Rate, LSWR）量化植被降温效率和不透水面增温效率并对2017年江苏省南京市城市热环境进行分析。以Landsat 8 OLI 4期遥感影像为数据源,利用线性光谱混合分析法（Linear Spectral Mixture Analysis,LSMA）获取亚像元植被覆盖度（Fractional Vegetation Coverage, FVC）、不透水面覆盖度（Impervious Surface Percentage, ISP）并利用高分Google影像进行精度验证。结合地表温度（Land Surface Temperature, LST）反演结果计算各季总体LSCR和LSWR,分析不同LST对总体LSCR和LSWR的影响。最后,将FVC和ISP分别按照阈值平均划分为4个区间,计算各区间的LSCR和LSWR,并在此基础上分析不同区间LSCR和LSWR的变化情况。研究结果表明： ① LST与整体LSCR、LSWR正相关,夏季植被降温效应和不透水面增温效应最强,LSCR和LSWR分别为5.6%和5.1%;② 夏季各区间LSCR与FVC正相关,FVC为75%~100%时LSCR达到最大值7.5%;各区间LSWR与ISP负相关,ISP为75%~100%时LSWR达到最小值2.4%;③ 当FVC为0~25%,ISP为75%~100%时,可以充分发挥植被的降温效应,抑制不透水面的增温效应,是最佳的植被和不透水面组合方案。本研究采用的LSCR和LSWR分析方法可以从抑制地表温度上升的角度选择最佳的FVC和ISP区间,未来可基于此横向对比不同城市,并结合纬度、地形、气候、树种等因素对LSCR和LSWR的影响,进一步探索LSCR和LSWR的影响因子和变化规律。 相似文献
6.
不透水面是城市区域中一种典型的土地覆盖类型,是衡量城市环境质量和城市化水平的重要标志之一。与传统基于像元级的遥感研究方法相比,不透水面百分比（Impervious Surface Percent,ISP）的估算可以进入像元内部,获得更准确的城市信息。本文应用Cubist模型树,对Landsat TM的原始波段变量（除热红外波段）,建立ISP估算的基础模型（Base Cubist-ISP）。通过基于模型树的集成学习优化算法和加入相邻时相影像的波段变量中值,以削弱噪声的影响。然后,优选热红外波段和各种衍生变量,并进行属性精简,继而应用集成学习算法得到的参数和精简后的变量建立ISP估算的优化模型（Optimal Cubist-ISP）。对广东省广州市海珠区的实验结果表明,Optimal Cubist-ISP模型估算不透水面的整体均方根误差（RMSE）为12.98%,决定系数（R2）为0.90,精度明显优于Base Cubist-ISP模型,RMSE降低约5.03%,ISP在透水面区域被高估和高密度不透水面区域被低估的现象得到改善。本文提出的基于Cubist模型树建立ISP遥感估算的模型及优化方法可以适用于城市区ISP的提取。 相似文献
7.
《中国海洋大学学报(英文版)》2020,(5)
Jacket-type offshore platforms are widely used for oil, gas field, and energy development in shallow water. The design of a jacket structure is highly dependent on target environmental variables. This study focuses on a strategy to estimate design loads for offshore jacket structures based on an environmental contour approach. In addition to the popular conditional distribution model, various classes of bivariate copulas are adopted to construct joint distributions of environmental variables. Analytical formulations of environmental contours based on various models are presented and discussed in this study. The design loads are examined by dynamic response analysis of jacket platform. Results suggest that the conditional model is not recommended for use in estimating design loads in sampling locations due to poor fitting results. Independent copula produces conservative design loads and the extreme response obtained using the conditional model are smaller than those determined by copulas. The suitability of a model for contour construction varies with the origin of wave data. This study provides a reference for the design load estimation of jacket structures and offers an alternative procedure to determine the design criteria for offshore structures. 相似文献
8.
建筑工程板状砼地基属地下工程,其施工质量的检测与控制难度较大。根据该类工程的特点（面积大,厚度小）,可将其视为二维结构,采用弹性波ＣＴ成像方法检测其施工质量,在工程实践中取得了满意的效果。本文将结合工程实例介绍板状砼地基浇注质量的ＣＴ检测技术,包括弹性波ＣＴ的基本原理、野外数据采集系统的设计以及数据处理方法。 相似文献
9.
从系统设计思想、结构和功能等方面详细介绍了安徽省农业气象情报服务系统。该系统采用面向对象技术,选用VisualBasic5.0和Office97的VBA语言编程,主要实现农业气象旬(月)报(HD-03)AB报的翻译及处理分析、情报材料的编撰、情报报表的制作、历年灾情的查询以及农业气象周年服务方案的编排和历年服务产品的检索查询等功能 相似文献
10.
在碾压混凝土结构中进行接缝灌浆，是目前坝工研究的重要技术问题。以某工程为例，详细分析了影响接缝灌浆质量的因素，提出了特殊条件下接缝灌浆的技术方法 相似文献
11.
郭科 《成都信息工程学院学报》1997,(3)
作者应用模型简化技术中的矩阵摄动法来修改结构动力参数，从而避免了修改后结构动力参数的重计算，减少了系统仿真、分析和设计的计算量。算例表明，该方法有较好的计算效率。 相似文献
12.
Extreme water level is an important consideration when designing coastal protection structures. However, frequency analysis recommended by standard codes only considers the annual maximum water level, whereas water levels should actually be regarded as a combination of astronomical tide and storm surge. The two impacting factors are both random variables, and this paper discusses their dependency structures and proposes a new joint probability method to determine extreme design water levels. The lognormal, Gumbel, Weibull, Pearson type 3, traditional maximum entropy, and modified maximum entropy distributions are applied to fit univariate data of astronomical tides and storm surges separately, and the bivariate normal, Gumbel-Hougaard, Frank and Clayton copulas are then utilized to construct their joint probability distributions. To ensure that the new design method is suitable for use with typhoon data, the annual occurrence frequency of typhoon processes is considered and corresponding bivariate compound probability distributions are proposed. Based on maximum water level data obtained from Hengmen hydrological station in the Pearl River Basin, China, these probability models are applied to obtain designs for extreme water levels using the largest sum of the astronomical tide and storm surge obtained under fixed joint return periods. These design values provide an improved approach for determining the necessary height of coastal and offshore structures. 相似文献
13.
Alaska pollock is an important protein source which is extensively used in the food industry. Pollock protein isolates(PPI) with significantly enriched protein contents could be prepared using isoelectric solubilization/precipitation(ISP) processing; however, the functional properties of this process is limited by the large amount of water-insoluble proteins. In this study, we investigated the influence of high hydrostatic pressure(HHP) treatment on the solubility and structural changes of PPI. PPI obtained using ISP is treated with hydrostatic pressures of 200, 300, 400, and 500 MPa for up to 15 min, and the HHP-treated samples were observed to exhibit significantly improved solubilities. Further biochemical assays reveal that the continuous HHP treatments reduce the contents of free sulfhydryl groups and promote the formation of macromolecules with better water solubilities, which may induce the solubility improvements of the HHP-treated PPI. Our results indicate that HHP can be utilized to effectively prepare highly water-soluble Alaska pollock protein in food processing. 相似文献
14.
Considering the dependent relationship among wave height, wind speed, and current velocity, we construct novel trivariate joint probability distributions via Archimedean copula functions. Total 30-year data of wave height, wind speed, and current velocity in the Bohai Sea are hindcast and sampled for case study. Four kinds of distributions, namely, Gumbel distribution, lognormal distribution, Weibull distribution, and Pearson Type III distribution, are candidate models for marginal distributions of wave height, wind speed, and current velocity. The Pearson Type III distribution is selected as the optimal model. Bivariate and trivariate probability distributions of these environmental conditions are established based on four bivariate and trivariate Archimedean copulas, namely, Clayton, Frank, Gumbel-Hougaard, and Ali-Mikhail-Haq copulas. These joint probability models can maximize marginal information and the dependence among the three variables. The design return values of these three variables can be obtained by three methods: univariate probability, conditional probability, and joint probability. The joint return periods of different load combinations are estimated by the proposed models. Platform responses (including base shear, overturning moment, and deck displacement) are further calculated. For the same return period, the design values of wave height, wind speed, and current velocity obtained by the conditional and joint probability models are much smaller than those by univariate probability. Considering the dependence among variables, the multivariate probability distributions provide close design parameters to actual sea state for ocean platform design. 相似文献
15.
The Oscillating Water Column(OWC)wave energy convertor with the advantage of its simple geometrical construction and excellent stability is widely employed. Recently, perforated breakwaters have been often used as they can effectively reduce the wave reflection from and wave forces acting on the structures. Considering the similarity between the compartment of perforated caisson and the air chamber of OWC wave energy convertor, a new perforated caisson of breakwater is designed in this paper. The ordinary caisson is modified by installing facilities similar to the air chamber of OWC convener, but here they are utilized to dissipate the wave energy inside the caisson. Such an arrangement improves the stability of the caisson and reduces the construction cost by using the compartment of perforated caisson like using an air chamber. This innovation has both academic significance and important engineering value. For a new type of caisson, reliability analysis of the structure is necessary. Linear potential flow theory is applied to calculate the horizontal wave force acting on the caisson. The calculated results are compared with experimental data, showing the feasibility of the method. The Importance Sampling Procedure(ISP)is used to analyse the reliability of this caisson breakwater. 相似文献
16.
Dike failure and marine losses are quite prominent in Laizhou Bay during the period of cold wave storm surges because of its open coastline to the north and flat topography. In order to evaluate the intensity of cold wave storm surge, the hindcast of marine elements induced by cold waves in Laizhou Bay from 1985 to 2004 is conducted using a cold wave storm surge–wave coupled model and the joint return period of extreme water level, concomitant wave height, and concomitant wind speed are calculated. A new criterion of cold wave storm surge intensity based on such studies is developed. Considering the frequency of cold wave, this paper introduces a Poisson trivariate compound reconstruction model to calculate the joint return period, which is closer to the reality. By using the newly defined cold wave storm surge intensity, the ‘cold wave grade' in meteorology can better describe the severity of cold wave storm surges and the warning level is well corresponding to different intensities of cold wave storm surges. Therefore, it provides a proper guidance to marine hydrological analysis, disaster prevention and marine structure design in Laizhou Bay. 相似文献
17.
郭静 《成都信息工程学院学报》2007,22(6):692-695
针对传统自动化测试方法的缺陷,基于AJAX关键技术和异步工作模式,分析及设计了一种适合于AJAX Web应用程序的异步自动化测试方法.重点介绍了此异步自动化测试技术的框架构建以及一对核心程序定义函数:access和wait的设计实现. 相似文献
18.
根据不同遥感平台，详细叙述地基、塔基、机载和星载GNSS-R技术土壤水分监测的发展现状，综述辐射计联合GNSS-R技术进行土壤水分监测的发展状态及GNSS-R地基和星载接收机的发展现状，探讨GNSS-R/IR进行土壤水分反演的重难点。 相似文献
19.
通过对BDS/INS深组合导航进行较为全面的性能分析（重点针对INS辅助BDS捕获、跟踪环路机理及性能评判准则）发现,在INS辅助下可以显著提高BDS信号捕获灵敏度、缩短平均捕获时间,并可以维持环路的锁定跟踪状态以提高导航精度。同时,考虑GNSS接收机受到超强干扰或卫星信号受到持续遮挡等特殊条件,给出BDS/INS深组合的结构设计,并基于软件接收机对深组合导航系统性能进行仿真分析。该仿真结果对工程应用具有参考价值。 相似文献
20.
Magnetotelluric(MT)inversion and seismic inversion are important methods for the interpretation of subsurface exploration data,but separate inversion of MT and seismic produces ambiguous and non-unique results due to various factors.In order to achieve accurate results,the authors propose a joint inversion method of two-dimensional MT and seismic data in the frequency domain.The finite element method is used for numerical simulation of electromagnetic data in the forward modelling,and the Gauss-Newton method is used for the inversion.The 9-point-finite-difference method is used to solve the seismic wave field in the acoustic wave equation,and the inverse problem of seismic data is solved by full waveform inversion with a conjugate gradient,a simple and fast method.Cross gradient functions are used to provide constraint structure between resistivity and velocity parameters to carry out the joint inversion.The joint inversion algorithm is tested by double-rectangular model synthesis data,and the accuracy of the algorithm is verified.The results show that the joint inversion results are better than those from separate inversion.The algorithm is applied to a geophysical model of a metalliferous deposit in Jinchuan and is compared with the separate inversion results.It shows that the results obtained with joint inversion are much closer to the real model. 相似文献