基于三维真实场景的落叶松林参数敏感性分析

森林冠层结构对太阳辐射能量有重要的影响,而双向反射率因子（BRF）在植被冠层反射研究中对冠层的生物物理特性起重要作用。本文在针叶树简化实验和落叶松模拟的基础上,分析了 BRF对落叶松及其环境参数的敏感性：叶面积指数(LAI)、太阳位置、地面背景和天空光比例。研究结果表明冠层的空间结构分布、地面背景的类型对BRF有很大的影响。     

树形算法在电信客户细分中的应用研究

树形算法由于其对大量高维数据的有效处理、对噪声点的高容忍度和对知识的有效表示,是最常用的CRM客户细分技术。通过对几类树形算法,包括决策树C4.5算法、决策树CART算法和平衡随机森林BRF算法,在解决电信客户细分问题中的表现进行分析研究,并且选用BP神经网络算法作为树形算法的参照,最终研究得出:平衡随机森林在处理电信客户问题上具有最好的表现。     

碳化硅薄膜的ICP浅刻蚀工艺研究

选用SF6/O2 混合气体对等离子体增强化学气相淀积( PECVD)法制备的碳化硅( SiC)薄膜进行了浅槽刻蚀,并通过正交试验设计方法,研究了感应耦合等离子体( ICP)刻蚀技术中反应室压强、偏压射频( BRF)功率、O2 比例三个工艺参数对碳化硅薄膜刻蚀速率的影响及其显著性.实验结果表明:BRF功率对于刻蚀速率的影响具有高度显著性,各因素对刻蚀速率的影响程度依次为BRF功率>反应室压强>O2 比例,并讨论了所选因素对碳化硅薄膜刻蚀速率的影响机理.     

基于RBF网络的粮食水分检测数据融合研究

为了提高测量的准确性和快捷性,需要融合处理多传感器检测的数据。本文首先介绍BRF网络的特性和训练方式,然后进行样本数据采集、样本数据归一化、神经网络的训练及其结构的确定,完成基于RBF网络的水分检测数据处理过程,实现粮食水分检测中的多传感数据融合。经过Matlab中的神经网络模型训练后,实验结果表明,拟合值始终在目标值上下波动,波动的范围在7%以内,该方法具有较大的优越性,可在其它工业领域中推广应用。     

基于2维激光雷达的小型地面移动机器人自主回收方法

为了解决小型地面移动机器人在野外环境中的回收问题,利用2维激光雷达进行环境感知与末端精确引导,设计并实现了一个自主回收系统.首先,提出一种自适应曲率滤波算法预先对雷达数据进行滤波处理.然后,在检测引导目标过程中,结合基于密度和最近邻度量方法对散乱的数据进行聚类,并且利用引导目标和辅助目标之间的几何结构约束进行目标检测与匹配.最后,采用基于影响层划分和候选方向评估的方法进行实时避障与最优行驶方向选择,对机器人进行精确引导,从而实现机器人的自主回收.在野外环境中对该自主回收系统进行验证,对自主回收系统中的若干环节分别进行实验分析.实验结果表明,该方法能够有效地实现小型地面移动机器人在野外环境中的自主回收.     

基于深度学习的温度观测数据长时间缺失值插补方法

完整高精度的温度观测数据是农业气象灾害监测、生态系统模拟重要的输入参数.由于野外气象观测条件的限制,气象观测数据缺失现象是常态,数据插补方法是气象数据应用必要处理步骤.本文针对野外小气象观测站站点半小时温度观测数据长时间缺失值问题,结合同一地点较低频次的人工温度观测,构建了新的温度缺失值插补深度学习模型,对缺失的半小时...     

采用改进重采样和BRF方法的定义抽取研究

为了从专业领域语料中发现并获取所有的专业术语定义,该文提出了使用分类方法进行专业术语定义抽取的方法。该文采用一种基于实例距离分布信息的过采样方法,将其与随机欠采样方法结合用以建立平衡训练语料,并使用BRF(Balanced Random Forest)方法来获得C4.5决策树的聚合分类结果。该方法获得了最好65%的F1-measure成绩和78%的F2-measure成绩,超过了仅使用BRF方法取得的成绩。     

地形因子对森林冠层BRF模拟的影响分析

针对利用计算机模拟模型进行森林冠层BRF模拟时,地形因子——高程、坡度和坡向对森林冠层接收太阳辐射的影响等问题,本文探讨了利用RGM(Radiosity-Graphics combined Model)模型进行森林冠层反射特性的研究,研究了将森林生长ZELIG模型和L-系统结合起来构建三维森林场景,并采用RGM模型模拟森林冠层的二向性反射特性。研究结果表明地形因子对BRF分布影响非常明显。     

蓝牙芯片BRF6150在智能家居中的应用

首先介绍德州仪器(TI)发布的面向便携终端产品的蓝牙芯片BRF6150的内部组成结构和工作原理。然后将其应用到智能家居系统中的核心部件智能家居综合控制器的设计中。在对智能家居综合控制器的硬件组成进行详细描述的基础上,给出蓝牙芯片BRF6150与多媒体应用处理器OMAP5910的硬件引脚连接图和二者之间通信的软件实现方法。最后介绍智能家居系统中蓝牙通信的实现和应用。     

基于关键点的Anchor Free目标检测模型综述

目标检测是计算机视觉应用的基础, 基于锚框的一些目标检测算法已难以满足目标检测中对目标处理的效率、性能等诸多方面的要求, 而anchor free方法逐渐广泛应用于目标检测. 本文首先重点介绍了CornerNet、CenterNet、FCOS模型的一系列基于关键点的anchor free目标检测方法, 综述了算法思路及其优缺点; 然后分别对基于锚框和基于关键点的目标检测算法在同一个数据集上作了性能比较和分析; 最后对基于关键点的目标检测进行了总结, 并展望了目标检测的未来发展方向.     

虚拟仪器测试系统及其Web数据管理研究

根据LabVIEW测试系统数据处理方面的实际需要,通过数据库访问工具包LabSQL,实现了LabVIEW对专业数据库SQL Server的访问,在此基础上开发的虚拟仪器测试系统,有效地解决了处理大量数据信息的问题。以ASP为脚本环境的网络服务器应用程序对SQL Server数据库中的实验数据的管理,是对实验数据应用的延伸,进一步扩大了虚拟仪器测试系统的应用范围。     

基于模式集成语义的查询处理

在采用面向对象模型作为公共数据模型的多数据库系统中，基于模式集成语义的查询处理不仅要实现针对集成模式查询到针对输出模式查询的转换，而且要从语义上尽可能减少回答用户查询所需数据，保证对象引用的正确性.为了达到这个目标,提出了一些新的概念及基于模式集成语义的查询处理规则和路径表达式的查询处理方法.     

Allometric constraints on sources of variability in multi-angle reflectance measurements

Bidirectional reflectance signatures of vegetation are strongly shaped by the shadows cast between objects in a scene, such as tree crowns or leaves. Differences in the shape and spatial density of these objects result in distinct bidirectional reflectance distribution functions (BRDFs) in different biomes. We examined how allometry may constrain the variability of canopy architectural parameters in BRDF models, and consequently alter the attribution of variation in the simulated bidirectional reflectance factor (BRF). Allometry is the covariation between the size or number of organisms and their component parts.To test the importance of realistic variation and covariation of canopy architecture on BRDF, we incorporated the 3-D radiative transfer model DISORD (which uses the geometric optics (GO) model of Li and Strahler) into a Monte Carlo (MC) algorithm. The MC algorithm generated an ensemble of tree canopies whose parameters fulfilled the allometry of a set of measured forest plots from Russian forest inventory. The role of view geometry was directly considered using perturbations of the parameters to evaluate the sensitivity of the BRF itself, evaluated at different view angles, and the difference in BRF (ΔBRF) as measured at two view angles representing paired satellite observations.The allometrically constrained forest plots had reduced variation in ΔBRF compared to the uncorrelated plots, but the variation of the BRF itself is dramatically increased by allometry. The variation of the BRF is relatively constant among the view angles examined, whereas the variation in ΔBRF increases dramatically with larger phase angles. The BRF was most sensitive to canopy attributes that were important in radiative transfer, such as LAI and stem area index (SAI), but there were also large (∼ 40% of variance) contributions of geometric components such as tree number, crown size, and ground cover. By contrast, sensitivity of ΔBRF was dominated by ground cover, crown size and tree number, which all play a role in the GO calculations. The mix of sensitive parameters was not dramatically different between gymnosperms and angiosperms, nor between allometric and correlated runs. Together these results indicate that forest structure and leaf area could be usefully inverted together using paired observations with different viewing geometries. Ideal pairs of observations are those with large difference in phase angle, and along the gradient of the BRF peak, which most commonly occur with sequential MODIS/Terra overpasses.     

制药前期开发的数据仓库解决方案

针对现有化学计量学的数据库解决方案在分析制药前期开发数据方面能力差的弱点，将数据仓库技术引人到药品开发领域，从分析制药前期开发的特征出发，提出了制药前期开发数据仓库(Pharmaceutical Leading Date Warehouse)的体系结构，并设计了其联机分析处理方案和实现措施，为药品开发提供了一种新颖的智能预测解决方案。     

Generating vegetation leaf area index earth system data record from multiple sensors. Part 1: Theory

The generation of multi-decade long Earth System Data Records (ESDRs) of Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation absorbed by vegetation (FPAR) from remote sensing measurements of multiple sensors is key to monitoring long-term changes in vegetation due to natural and anthropogenic influences. Challenges in developing such ESDRs include problems in remote sensing science (modeling of variability in global vegetation, scaling, atmospheric correction) and sensor hardware (differences in spatial resolution, spectral bands, calibration, and information content). In this paper, we develop a physically based approach for deriving LAI and FPAR products from the Advanced Very High Resolution Radiometer (AVHRR) data that are of comparable quality to the Moderate resolution Imaging Spectroradiometer (MODIS) LAI and FPAR products, thus realizing the objective of producing a long (multi-decadal) time series of these products. The approach is based on the radiative transfer theory of canopy spectral invariants which facilitates parameterization of the canopy spectral bidirectional reflectance factor (BRF). The methodology permits decoupling of the structural and radiometric components and obeys the energy conservation law. The approach is applicable to any optical sensor, however, it requires selection of sensor-specific values of configurable parameters, namely, the single scattering albedo and data uncertainty. According to the theory of spectral invariants, the single scattering albedo is a function of the spatial scale, and thus, accounts for the variation in BRF with sensor spatial resolution. Likewise, the single scattering albedo accounts for the variation in spectral BRF with sensor bandwidths. The second adjustable parameter is data uncertainty, which accounts for varying information content of the remote sensing measurements, i.e., Normalized Difference Vegetation Index (NDVI, low information content), vs. spectral BRF (higher information content). Implementation of this approach indicates good consistency in LAI values retrieved from NDVI (AVHRR-mode) and spectral BRF (MODIS-mode). Specific details of the implementation and evaluation of the derived products are detailed in the second part of this two-paper series.     

基于蒙特卡罗最小二乘的实验数据拟合方法

采用最小二乘法拟合化工实验数据,相关系数接近于1,精度高,但所得的结果与经验关联式大相径庭。蒙特卡罗方法是一种基于概率模型的非确定性数值方法。蒙特卡罗最小二乘拟合方法处理化工实验数据,应用中更为灵活,适用范围更广。在Excel电子表格中,利用工作表中的数据与VBA混合编程很容易完成蒙特卡罗最小二乘数据拟合,VBA实现与Excel电子表格的数据通讯及并行处理实验数据,读取工作表中的实验数据,计算随机点的大致搜索范围,进行最小二乘统计分析,将结果输出到工作表中。蒙特卡罗最小二乘拟合方法采用与最小二乘法相同的精度标准,在符合大数定理的基础上,精度大幅度提高。蒙特卡罗方法在随机搜索点较小时,误差很大,当随机搜索点达到10000时,其精度与最小二乘法相差无几,却得到与经验关联式十分接近的准数关系方程,取得了实践与理论统一的实验效果。     

Bidirectional reflectance of a rough anisotropic surface

The goal of our work was to demonstrate that the usual assumptions of isotropy and symmetry of the bidirectional reflectance factor (BRF) are not valid for a specific anisotropic ground surface. Two methods illustrating this point are presented. The first method is based on goniometer measurements, and the second method uses a Monte Carlo algorithm. The results of both methods were analysed at different wavelengths and angular configurations. For the surface studied here, they showed that the BRF was significantly asymmetric with respect to the principal plane. In the extreme case, the difference between the two sides of the principal plane reached almost 30% of the mean reflectance value.     

水陆两栖飞机的无线电高度数据处理方法研究

分析了水陆两栖飞机因水上起降和机腹船体构型导致的对无线电高度表数据进行零位基准修正、天线位置修正、负高度显示等特殊的处理要求.提出了零位基准设置的判据,建立了基于坐标变换矩阵,利用姿态角数据对零位基准设置、天线布置偏离零位基准等因素产生的测高误差进行修正的无线电高度数据处理方法,将姿态角的修正从俯仰角扩展到横滚角.应用...