浅析我国公开地图上国界线附近地名注记的表示方法

我国国界线附近的地名标注涉及行政地名、自然地名、历史地名、国外地名、少数民族地名等,其标注形式多种多样。本文在研究当前我国关于公开地图上地名表示相关规定的基础上,提出了公开地图上边界线附近地名的标注不仅应考虑地图编制方面的要求,更应注重地名的政治导向、历史由来及少数民族语言翻译标准等多方面因素。     

基于数字标识的敏感文件监控研究与实现

通过对系统剪贴板和网络出口数据的监控实现了终端系统敏感电子文件的监控。敏感电子文件由数字标识来标记,它指明了文件的密级和用户使用权限。采用Winpcap捕包机制并结合BM特征串模式匹配算法准确地监控网络出口数据。通过轮询剪贴板中的文件列表来监控系统的文件拷贝操作。实验表明,终端用户对敏感文件的非法操作系统都可以准确地监控并保存日志记录。     

Optimum placement and characteristics of velocity-dependent dampers under seismic excitation

In this study,through novel drift-based equations of motion in the frequency domain,optimum placement and characteristics of linear velocity-dependent dampers are investigated.In this study,the sum of the square of the absolute values of transfer matrix elements for interstory drifts is considered as the optimization index.Optimum placement and characteristics of dampers are simultaneously obtained by minimizing the optimization index through an incremental procedure.In each step of the procedure,a predefined value is considered as the damper characteristic.The optimum story for this increment is selected such that it leads to a minimum value for the optimization index.The procedure is repeated for the next increments until the optimization index meets its target value,which is obtained according to the desired damping ratio for the overall structure.In other words,the desired overall damping ratio is the input to the proposed procedure,and the optimal placement and characteristics of the dampers are its output.It is observed that the optimal placement of a velocitydependent damper depends on the damping coefficient of the added damper,frequency of the excitation,and distribution of the mass,stiffness,and inherent damping of the main structure.     

船载移动激光三维测量系统安置角偏差检校

船载移动激光三维测量系统是集激光扫描仪、全球定位系统和惯性导航测量单元等于一体的多传感器集成系统,具有效率高、精度高、三维测量等特点,可解决码头、河道、海岛礁测绘中传统方法难以测量的难题。船载移动激光三维测量系统的高精度时空同步是实现数据融合和高精度三维测量的保证,安置角偏差检校是船载移动激光三维测量的关键步骤。本文首先分析了船载移动激光三维测量系统中相关坐标系之间的转换关系,提出了一种以桥体为检校场的安置角偏差消除方法。该方法在时空配准的基础上,通过扫描测线内桥体结构的偏移量分别计算侧滚角、俯仰角及航向角的安置角偏差,最后通过控制点验证误差改正后的测量精度。试验结果证明,本文方法易于实施,且具有较高的准确性,能够有效保障船载移动激光测量数据的质量和精度。     

航次报告管理系统建设

航次报告(voyage report)是海洋学科出海科学考察过程和科学数据生产过程的纪实性原始记录,可为日后查询、统计、溯源、分析问题等工作提供重要依据.为改善航次报告的提交与评审工作目前基本全部由人工操作、成本高、效率低和出错率高的现状,本文设计开发了一套基于B/S(Browser/Server)架构的航次报告管理系...     

Differences in preferential flow with antecedent moisture conditions and soil texture: Implications for subsurface P transport

Preferential flowpaths transport phosphorus (P) to agricultural tile drains. However, if and to what extent this may vary with soil texture, moisture conditions, and P placement is poorly understood. This study investigated (a) interactions between soil texture, antecedent moisture conditions, and the relative contributions of matrix and preferential flow and (b) associated P distributions through the soil profile when fertilizers were applied to the surface or subsurface. Brilliant blue dye was used to stain subsurface flowpaths in clay and silt loam plots during simulated rainfall events under wet and dry conditions. Fertilizer P was applied to the surface or via subsurface placement to plots of different soil texture and moisture condition. Photographs of dye stains were analysed to classify the flow patterns as matrix dominated or macropore dominated, and soils within plots were analysed for their water‐extractable P (WEP) content. Preferential flow occurred under all soil texture and moisture conditions. Dye penetrated deeper into clay soils via macropores and had lower interaction with the soil matrix, compared with silt loam soil. Moisture conditions influenced preferential flowpaths in clay, with dry clay having deeper infiltration (92 ± 7.6 cm) and less dye–matrix interaction than wet clay (77 ± 4.7 cm). Depth of staining did not differ between wet (56 ± 7.2 cm) and dry (50 ± 6.6 cm) silt loam, nor did dominant flowpaths. WEP distribution in the top 10 cm of the soil profile differed with fertilizer placement, but no differences in soil WEP were observed at depth. These results demonstrate that large rainfall events following drought conditions in clay soil may be prone to rapid P transport to tile drains due to increased preferential flow, whereas flow in silt loams is less affected by antecedent moisture. Subsurface placement of fertilizer may minimize the risk of subsurface P transport, particularily in clay.     

Pre- and post-earthquake regional loss assessment using deep learning

As urban systems become more highly sophisticated and interdependent, their vulnerability to earthquake events exhibits a significant level of uncertainties. Thus, community-level seismic risk assessments are indispensable to facilitate decision making for effective hazard mitigation and disaster responses. To this end, new frameworks for pre- and post-earthquake regional loss assessments are proposed using deep learning methods. First, to improve the accuracy of the response prediction of individual structures during the pre-earthquake loss assessment, a widely used nonlinear static procedure is replaced by the recently developed probabilistic deep neural network model. The variabilities of the nonlinear responses of a structural system given the seismic intensity can be quantified during the loss assessment process. Second, to facilitate near-real-time post-earthquake loss assessments, an adaptive algorithm, which identifies the optimal number and locations of sensors in a given urban area, is proposed. Using a deep neural network that estimates area-wide structural damage given the spatial distribution of the seismic intensity levels as a surrogate model, the algorithm adaptively places additional sensors at property lots at which errors from surrogate estimations of the structural damage are the greatest. Note that the surrogate model is constructed before earthquake events using simulated datasets. To test and demonstrate the proposed frameworks, the paper introduces thorough numerical investigations of two hypothetical urban communities. The proposed frameworks using the deep learning methods are expected to make critical advances in pre- and post-earthquake regional loss assessments.     

综合多特征的极化SAR图像随机森林分类算法

为抑制相干斑噪声对极化SAR图像分类结果的干扰,本文提出一种综合多特征的极化SAR图像随机森林分类方法。该方法首先利用简单线性迭代聚类(SLIC)算法生成超像素作为分类单元;然后,基于高维极化特征图像,利用训练好的随机森林模型,统计决策树的分类投票数,计算各超像素的类别概率;最后,利用超像素间的空间邻域特征,采用概率松弛算法(PLR)迭代修正超像素的类别后验概率,并依据最大后验概率(MAP)准则得到分类结果;实现综合利用超像素和空间邻域特征,降低相干斑噪声干扰的极化SAR图像分类方法。实验对比结果表明:本文方法能得有效抑制极化SAR图像中相干斑噪声的干扰,得到高精度且光滑连续的分类结果。     

农产品质量溯源系统的研究

主要针对传统农产品质量追溯系统存在的广度较窄、精度不细致等问题,依托"热带特色农产品溯源系统"项目,利用无线射频识别技术,设计并实现农产品质量溯源系统,给出农产品质量溯源系统总体架构以及主要设计流程,并对标签转换、数据同步等关键技术进行阐述。