基于偏微分方程的户外图像去雾方法

户外图像的雾化往往导致色彩降质和对比度降低,有效的去除图像中天气效果对提高视觉系统的可靠性和鲁棒性具有重要意义。根据大气散射物理模型以及有雾图像的色彩与对比度降质同场景点的景深成指数关系的先验知识,分别建立了户外图像全局去雾和局部去雾的能量最优化模型,推导了相应的求解偏微分方程。利用用户提供的简单附加信息,实现了仅从单幅图像恢复清晰图像的去雾算法。实验结果表明：去雾图像的色彩清晰度和对比度有较大改善,具有很好的应用前景。     

基于图像的直接视觉伺服控制器设计与仿真

对于手眼机器人视觉伺服,考虑机器人的运动学及动力学特性,在物体的深度未知及机器人的基坐标系与物体的坐标系之间的相似变换矩阵未定标的情况下,设计了直接视觉伺服控制器,利用自适应算法对深度及上述相似变换矩阵的参数进行在线估计,实现了基于图像误差的定位控制,在系统的工作空间范围内,闭环系统是渐近可稳定的。该方法不需要物体的几何模型及深度的精确值,仿真结果验证了其有效性。     

强夯法在处理湿陷性黄土中的研究

从工程应用出发,阐述了强夯法在处理湿陷性黄土地基的加固机理以及强夯技术在处理黄土地基中的有效加固深度、夯击能等的确定,并对夯点的布置、夯击遍数和间歇时间和夯击加载机具的选择进行了介绍.     

Terrestrial isopods and myriapods in a forested scree slope: subterranean biodiversity,depth gradient and annual dynamics

Diversity, depth distribution and seasonal activity of isopods and myriapods were studied using subterranean traps buried in a forested limestone scree slope in the ?ierna Hora Mts, Western Carpathians, Slovakia, throughout the depth gradient from 5 to 95 cm. A total of five isopod, 13 diplopod and 11 chilopod species were identified. Most edaphic species strongly preferred the uppermost organic soil layers. Among the species captured, some represented rare stenoecous Carpathian endemics, namely the isopod Trichoniscus carpaticus, and diplopods Julus curvicornis and Leptoiulus mariae. Others were subterranean forms, partly adapted to hypogean conditions: the isopod Mesoniscus graniger, and diplopods Mecogonopodium carpathicum and Trachysphaera costata. The annual activity in the vast majority of the species ceased completely in winter, and was gradually relaunched in spring. In evaluating the age structure of two predominant diplopods Polydesmus denticulatus and Mecogonopodium carpathicum, both widespread across the depth gradient, a vertical segregation of early post-embryonic stages was found. While P. denticulatus tended to undergo the early stages of development in the soil-filled topmost levels, the early juvenile stage of M. carpathicum was distributed deep in the scree slope profile.     

A Time‐Simultaneous Prediction Box for a Multivariate Time Series

A sample‐based method in Kolsrud (Journal of Forecasting 2007; 26 (3): 171–188) for the construction of a time‐simultaneous prediction band for a univariate time series is extended to produce a variable‐ and time‐simultaneous prediction box for a multivariate time series. A measure of distance based on the L_∞ ‐norm is applied to a learning sample of multivariate time trajectories, which can be mean‐ and/or variance‐nonstationary. Based on the ranking of distances to the centre of the sample, a subsample of the most central multivariate trajectories is selected. A prediction box is constructed by circumscribing the subsample with a hyperrectangle. The fraction of central trajectories selected into the subsample can be calibrated by bootstrap such that the expected coverage of the box equals a prescribed nominal level. The method is related to the concept of data depth, and thence modified to increase coverage. Applications to simulated and empirical data illustrate the method, which is also compared to several other methods in the literature adapted to the multivariate setting. Copyright © 2015 John Wiley & Sons, Ltd.     

乌苏里江水深遥感反演

文中在分析卫星遥感测深机理的基础上,利用SVCHR-1024高光谱成像仪确定了可见光反演水深的最佳波段,通过对HJ星CCD数据各波段反射率、波段比值组合对水体、水深的敏感性分析,建立了适合于乌苏里江的单波段对数水深反演模型,从而快速获取乌苏里江河道地形信息,并探测了河道深泓线,整体精度达到80%以上.遥感反演水深可快速探测河道深泓线的方法,为乌苏里江河势演变研究提供了新的思路.     

时变流动性深度模型

使用超高频数据,并利用流动性深度指标,研究流动性的动态特征、影响因素以及检验市场微观结构理论.结果支持基于信息不对称下的市场微观结构理论.研究还表明耐心交易可以降低交易成本.     

单质对低碳钢A-TIG焊焊缝成形的影响

以Ti粉、Si粉和Te粉作为活性剂,研究了单质对低碳钢直流正接A-TIG焊焊缝成形的影响,分析了单质影响熔深的机理.在试验条件下,传统TIG焊的焊缝深宽比为0.24.添加三种活性剂后,焊缝表面都成形良好,Te粉使得焊缝余高增大.Ti粉和Te粉能显著增加熔深,Si粉对焊缝熔深影响则相对较小.Ti和Si粉能使熔宽收缩,而Te粉对熔宽几乎没有影响.在活性剂作用下,Ti粉的焊缝深宽比为0.43;而Te粉的为0.40,Si粉的只有0.35.Si粉、Ti粉、Te粉三者的焊缝熔深排序与其原子半径的大小顺序相同,焊缝熔深变化与单质原子半径大小关系密切.     

Studies on induction hardening of powder-metallurgy-processed Fe-Cr/Mo alloys

Induction hardening of dense Fe-Cr/Mo alloys processed via the powder-metallurgy route was studied. The Fe-3Cr-0.5Mo, Fe-1.5Cr-0.2Mo, and Fe-0.85Mo pre-alloyed powders were mixed with 0.4wt%, 0.6wt%, and 0.8wt% C and compacted at 500, 600, and 700 MPa, respectively. The compacts were sintered at 1473 K for 1 h and then cooled at 6 K/min. Ferrite with pearlite was mostly observed in the sintered alloys with 0.4wt% C, whereas a carbide network was also present in the alloys with 0.8wt% C. Graphite at prior particle boundaries led to deterioration of the mechanical properties of alloys with 0.8wt% C, whereas no significant induction hardening was achieved in alloys with 0.4wt% C. Among the investigated samples, alloys with 0.6wt% C exhibited the highest strength and ductility and were found to be suitable for induction hardening. The hardening was carried out at a frequency of 2.0 kHz for 2-3 s. A case depth of 2.5 mm was achieved while maintaining the bulk (interior) hardness of approximately HV 230. A martensitic structure was observed on the outer periphery of the samples. The hardness varied from HV 600 to HV 375 from the sample surface to the interior of the case hardened region. The best combination of properties and hardening depth was achieved in case of the Fe-1.5Cr-0.2Mo alloy with 0.6wt% C.     

南京长江第四大桥钢箱梁铺装层温度影响系数分析

为了减少现有的钢桥面铺装层车辙深度预估的误差,提出基于长期实测数据的钢桥面铺装车辙评估模型的温度影响系数计算公式。首先对南京长江第四大桥的实测温度概率统计后采用双高斯函数表征其分布;在此基础上修正了现有车辙评估模型中的温度影响系数公式,并利用车辙实测数据对车辙评估模型计算值进行验证。研究结果表明:钢箱梁复合浇筑式铺装层温度可通过双高斯分布描述其概率分布;计入温度影响系数的车辙深度与实际车辙值之间误差较小,相对误差为15.2%。