Improved Prediction and Reduction of Sampling Density for Soil Salinity by Different Geostatistical Methods

The spatial estimation for soil properties was improved and sampling intensities also decreased in terms of incorporated auxiliary data. In this study, kriging and two interpolation methods were proven well to estimate auxiliary variables： cokriging and regression-kriging, and using the salinity data from the first two stages as auxiliary variables, the methods both improved the interpolation of soil salinity in coastal saline land. The prediction accuracy of the three methods was observed under different sampling density of the target variable by comparison with another group of 80 validation sample points, from which the root-mean-square error （RMSE） and correlation coefficient （r） between the predicted and measured values were calculated. The results showed, with the help of auxiliary data, whatever the sample size of the target variable may be, cokriging and regression-kriging performed better than ordinary kriging. Moreover, regression-kriging produced on average more accurate predictions than cokriging. Compared with the kriging results, cokriging improved the estimations by reducing RMSE from 23.3 to 29% and increasing r from 16.6 to 25.5%, regression-kriging improved the estimations by reducing RMSE from 25 to 41.5% and increasing r from 16.8 to 27.2%. Therefore, regression-kriging shows promise for improved prediction for soil salinity and reduction of soil sampling intensity considerably while maintaining high prediction accuracy. Moreover, in regression-kriging, the regression model can have any form, such as generalized linear models, non-linear models or tree-based models, which provide a possibility to include more ancillary variables.     

基于GIS和生态敏感性分析的城乡公园地块规划研究

以盐城市盐龙体育公园景观规划为例,分析高程、坡度、坡向、植被覆盖度、水域敏感因子,计算生态敏感性评价总值。对生态敏感程度进行分级,确定各敏感因子的敏感程度,对GIS高程数据进行预处理,采用方根法计算生态敏感因素的权重。在GIS技术支持下,设计规划原则,通过ArcGIS软件实现向量文档的数字化,根据研究区生态环境状况,将生态功能区划分为生态保育区、生态缓冲区、生态管制区和开发建设区,基于此,设计出城乡公园地块规划效果图。     

基于频域特征参数曲线拟合法的柴油机故障诊断

柴油机的频域分析是指将所测得时域信号经过某种变换(如傅立叶变换),将其转换到频域进行分析的一种方法.频域特征参数主要包括重心频率FC、均方频率MSF、方根频率RMSF、频率方差VF和频率标准差RVF.本文利用柴油机工作时频域特征参数拟合曲线与所设标准故障频域特征参数拟合曲线之间的距离来判断柴油机故障类型.     

基于地表数码照相的林地总体植被覆盖度计算模型

Vegetation fractional coverage (VFC) is one of the key indicators of vegetation distribution. In the work a measurement-based model was developed to derive total forest VFC (TG) as well as the VFC of trees (T) and shrub-grasses (G) separately in a subtropical forest area in Nanjing, China. Both upward and downward photographs were taken with a digital camera in 72 quadrats (10 m × 10 m each). Fifteen models were established and validated. Models jointly using both T and G performed better than those using the T and G separately. The best model, TG = T + G- 1.134 × T × G- 0.025 (R2 = 0.9115, P 0.01, root mean squared error = 0.0789), is recommended for application. This model provides a good way to obtain total forest VFC values through taking tree and shrub-grass photos on ground below tree canopy rather than above tree canopy.     

我在外打工 丈夫在家养情人

我出生在临川区的一个村里,两姐妹里我排行老大,手下还有一个妹妹。在我10岁那年,母亲离开人世,父亲一个人拉扯着我们姐妹俩。我12岁那年,村支书带着几个村干部上我家玩,聊家常时,村支书看了看我,想起了村中的孤儿方根(化名)。方根     

基于遗传算法的波长选择方法在绿茶近红外光谱分析模型中的应用

利用遗传算法（GA）提取茶叶的近红外吸收特征波长的方法,研究建立了绿茶所含水分和氨基酸的近红外分析模型,并对波长选择前后两种成分的模型进行了比较分析。结果表明,经遗传算法波长选择后,简化了分析模型,同时模型的稳健性增强。氨基酸预测集的均方根误差（SEP）减少82．1％,水分预测集的均方根误差减少76．6％,它们在波长选择前后对应的分析波长数之比分别为995：7和1990：33。     

关于柴油三轮农用运输车降振的研究

针对三轮农用运输车振动大的问题,采用新的连接方式,改变之前三轮车与柴油机硬连接的方式,在三轮车与柴油机连接处增加单向悬置隔振器,经过精准的计算和试验验证,三轮车综合各个工况下,振动值降低8％～12％,使整体质量进一步得到提升.     

消除偏差集合平均在黄海渤海大风预报中的应用

基于日本气象厅预报模式（JMA）、美国国家环境预报中心预报模式（NCEP GFS）及美国海军全球大气预报谱模式（NOGAPS）3个模式2009年6月28日~8月10日每日20：00预报的海面风场预报资料,利用消除偏差集合平均对海面风场进行预报试验,并采用均方根误差对预报结果进行检验评估。结果表明,对于24、48 h海面风场预报,消除偏差集合平均有效地减小了预报的均方根误差,预报效果优于单个模式的预报;其中,渤海中部偏南地区及黄海中部误差减小最为明显。此外,消除偏差集合平均预报明显改善了2009年7月13~14日和8月7日大风过程的预报效果,提高了风速值和大风区位置的预报准确率。     

采用声学多普勒测速技术研究鱼的游动

本研究评估了使用声学多谱勒测速（ADV）研究鱼类游动的适用性。ADV使得探测并定量鱼群密度和由鱼类游动产生的湍流之间的关系成为可能，也使得显示鱼类在黑暗期和光照期的游动形式差异成为可能。使用速度均方根（RMS）作为鱼类游动的一个指标，并使用一个带有内部采样率为100Hz，每秒采集25个速度数据的ADV探头对湍流进行评估。     

贵州省ET_0计算方法的全局性评价及其率定

为了获取适合贵州地区时空全局的参考作物需水量少参数计算方法,根据对贵州省1959-2011年降雨量的降雨频率曲线分析,选取了2008年、2007年、2010年和2009年分别作为贵州省丰水年、平水年、枯水年和特枯水年的典型代表水平年,分别运用少参数的Hargreaves法、Hargreaves修正法、Priestly-Taylor法、Irmak-Allen法和Mccloud法计算贵州全省内各站点在不同水平年的逐日ET0,并将其与标准的FAO-56Penman Monteith法计算结果进行相关性和误差分析。结果表明:Hargreaves法、Hargreaves修正法、Priestly-Taylor法和Irmak-Allen法与FAO-56PM法的相关性较好,趋势线斜率为0.855 9~1.186 4,相关系数均大于0.89;经过当地率定后无需风速资料的Priestly-Taylor法与Irmak-Allen法在不同水文年和空间上均具有较高的计算精度,相对误差均小于8%,均方根误差为0.25mm/d,率定后仅需温度资料的Hargreaves法次之,相对误差为10.07%,均方根误差为0.32mm/d。研究结果为贵州地区在资料缺乏气象资料情况下ET0的精确计算提供了有效的方法。