基于斜率特征的模拟电路故障诊断新方法

针对低可测性模拟电路存在的模糊组问题,提出一种模拟电路故障诊断新方法。利用不同元件在电路可及节点间的斜率特征关系建立斜率测试矩阵,依据斜率测试矩阵准确找到电路中存在的模糊组和独立可测元件,从而确定可诊断集,然后利用支持向量机对故障进行诊断。斜率法优点在于不需要对电路拓扑结构进行分析,计算简便,支持向量机结构简单,泛化能力强。实验表明该方法具有良好的模拟电路故障诊断效果。     

Summary of research on soil testing for rock phosphate fertilizers in Western Australia

The relationship between plant yield and values of soils tests for phosphorus (P) was studied in long-term field experiments in south-western Australia for soil previously fertilized with rock phosphate and superphosphate. The rock phosphates studied were: Queensland (Duchess) apatite rock phosphate; reactive apatite rock phosphate from North Carolina; and rock phosphate from Christmas Island (as either C-grade ore or Calciphos). The P fertilizers were applied once only at the start of each experiment, and in subsequent years, soil samples were collected in January-March to measure soil test values. These were compared with plant yields measured later on in that year. The Colwell alkaline bicarbonate soil test was used in all years in all experiments. Olsen, Bray, lactate and Troug tests were used in some years in some experiments. For all soil tests the relationships between yield and soil test values was generally different for rock phosphate and superphosphate. For a given source of P, none of the different soil test reagents was significantly superior for predicting plant yields. The relationship between yield and soil test value was also generally different for different plant species. At one site cultivation was included as a treatment and the relationship varied depending on the cultivation treatment of the topsoil before sowing oats (Avena sativa). The relationship between yield and soil test also differed between years.     

考虑土体强度参数深度依赖性的非平稳随机场边坡滑动深度和体积分析

基于随机有限元方法（RFEM）和Monte-Carlo模拟,建立了能够模拟具有深度依赖性的土体强度参数边坡或具有软弱夹层边坡的非平稳随机场模型。通过辐射扫描方法获取最危险滑动面,得到非平稳随机场边坡滑动深度和滑动体积。将该方法与均质边坡和平稳随机场边坡获得的滑动深度和滑动体积进行对比,研究土体强度参数深度依赖性的非平稳随机场边坡的不同坡度和各向异性对滑动深度和滑动体积的影响。结果表明：基于RFEM的非平稳随机场滑动深度和滑动体积结果为地质灾害风险及后果评估提供了一个参考分析的新角度;参数的深度依赖性程度越高(变化率b越大),则边坡平均滑动深度和滑动体积越小;在大坡度滑坡风险后果评估中,可以基于均质边坡分析结果进行初步预估;在非平稳随机场中,随着各向异性的增大,所有坡度边坡的滑动体积变异系数增大;不同坡度下,水平方向的相关程度越大,则土坡内软弱夹层的不确定性越强,滑动体积的变异系数也不断增大。     

基于slope one算法改进评分矩阵填充的协同过滤算法研究

为解决协同过滤算法中的数据稀疏性问题,提出了一种改进的协同过滤算法。该算法使用slope one算法计算出来的评分预测值来填充评分矩阵中的未评分项目,然后在填充后的用户-项目评分矩阵上通过基于用户的协同过滤方法给出推荐。利用slope one算法计算出来的评分预测值作为回填值,既能降低评分矩阵的稀疏性,也保证了回填值的多样性,从而减少均值、中值等单一填充值造成的推荐误差。在MovieLens-1M数据集上对本文改进算法和协同过滤算法及均值中心化处理的算法作五折交叉实验,结果表明,基于评分预测值填充数据后的协同过滤算法有效的缓解了数据稀疏性问题,并且有更好的推荐效果。     

陡坡傍山双层行车结构体系受力特性分析

以山区常见的40°陡坡地形条件下修建4车道高等级公路为例,提出一种环境和经济效益俱佳的新型"桩-锚-框架"复合双层行车结构体系,该体系具有双层行车、山体锚固、边坡支挡和路面支撑等众多功能。采用ABAQUS大型有限元分析软件对该双层行车结构体系进行三维数值模拟,探究其受力特性。研究结果表明:该结构体系具有良好的承载能力和静力稳定性,对陡坡山体有较强的支护作用;支撑柱和横梁的相交位置是整个结构体系应力较集中的部位,应适当增加该节点的配筋量以提高强度、改善节点受力情况。     

二郎山滑坡坡脚挡墙破坏及修复技术研究

二郎山1号滑坡位于龙胆溪左岸,滑坡前缘采用了坡脚挡墙防冲刷工程,10 a之后位于龙胆溪凹岸部分坡脚挡墙破坏。针对坡脚挡墙破坏形成的原因,对比分析了目前常用冲刷防护结构的局限性,提出了采用台坎式挡墙新组合结构进行修复,组合结构主要由挡土墙、墙底抗滑键、墙脚台坎以及耐磨肋组成。介绍了组合结构设计计算方法,并通过造价分析说明台坎式挡墙结构与其它防冲刷相比在经济上具有明显优越性,可为其它同类地质灾害防治提供参考。     

某坝肩边坡开挖优化设计方案研究

为了研究前坪水库右坝肩边坡在设计方案和优化设计方案开挖下的边坡稳定性分析,采用数值分析和极限平衡法进行研究,首先针对边坡典型剖面进行了数值分析,研究边坡的位移和应力分布规律,然后运用极限平衡法得出边坡的安全系数,两种方法结合不仅可以反映边坡的稳定性和位移场之间的关系,而且可以用工程界所熟悉的安全系数来评价边坡的稳定性。结果表明边坡开挖优化设计方案满足边坡稳定性规范要求,且优化方案减少了开挖量,节省了工程投资,使得工程尽早发挥效益。     

Variability of light absorption properties in optically complex inland waters of Lake Chaohu,China

Absorption coefficients of phytoplankton, colored detrital matter (CDM), non-algal particles (NAP), colored dissolved organic matter (CDOM), and their relative contributions to total non-water absorption (a_t ? w) are essential variables for bio-optical and radiative transfer models. Light absorption properties showed large range and variability sampled at 194 stations throughout Lake Chaohu between May 2013 and April 2015. The a_t ? w was dominated by phytoplankton absorption (a_ph) and NAP absorption (a_d). The contribution of CDOM absorption to a_t ? w was lower than 30%. Phytoplankton and NAP were the primary sources of spatial and vertical variability in absorption properties. Light absorption by CDOM, though significant in magnitude, was relatively constant. CDM absorption (a_dg) was dominated by NAP. The spatial variation of the absorption coefficients from each of the optically active constituents were driven by several main inflow rivers in the western and middle part of Lake Chaohu. Algal blooms and bottom resuspension contributed to vertical variability as observed by phytoplankton and NAP profiles. Specific absorption of phytoplankton had significant spatial and seasonal variations without vertical variation. The spectral slope of absorption showed no significant spatial variability (p > 0.05). Variations of absorption affected different ranges of remote sensing reflectance (R_rs) spectrum, thereby increasing the difficulty of applying the remote sensing algorithm in optically complex waters. Parameters and relationships presented in this study provide useful information for bio-optical models and remote sensing of lakes similar to Lake Chaohu in terms of optical properties.     

岩盐溶解速率的研究

在岩盐溶解速率及其影响因素的实验研究基础上,建立了岩盐溶解速率的计算公式。研究的结果可为岩盐开采和其他水溶法矿物开采提供参考。     

基于改进A*算法的越野路径规划研究

针对车辆的越野路径规划问题, 研究并分析了地形坡度和地表属性对于车辆路径规划的综合影响。引入了窗口移动法对地形进行先期的坡度计算和通行性分析, 就轮式车辆和履带式车辆分别建立了地表属性的粗糙度评价指标, 并采用面积占优法将地表属性栅格化。通过建立禁忌表, 叠加了坡度与粗糙度的约束影响以减少搜索范围, 提高搜索效率。构造了改进A*算法的估价函数, 并结合expand表、open表、closed表以及path表设计了考虑坡度和粗糙度约束的路径优化算法。仿真结果表明, 该算法能够快速有效地实现符合真实地形环境的越野路径规划。