湿地是"地球之肾",对地球生物生存具有重要意义。由于湿地水域面积的破碎化程度高,常规利用遥感技术提出的水体指数不够有效,简单快速的实时监测技术还需完善。以2009年杭州湾湿地的Landsat TM影像为基础数据,选择不同水域类...湿地是"地球之肾",对地球生物生存具有重要意义。由于湿地水域面积的破碎化程度高,常规利用遥感技术提出的水体指数不够有效,简单快速的实时监测技术还需完善。以2009年杭州湾湿地的Landsat TM影像为基础数据,选择不同水域类型,构建新型水体指数(water zscore-band5,WZ5),与常用的改进的归一化差异水体指数(modified normalized difference water index,MNDWI),混合水体指数(combined index of NDVI and NIR for water body identification,CIWI)进行对比,分析各指数湿地水域信息提取的准确性和完整性。结果表明:所构建的指数WZ5水体信息提取精度优于MNDWI和CIWI,特别是含有大量塘基且分布复杂的水产池塘破碎区,WZ5计算水体与塘基的区分度为41.78%,大于MNDWI(21.59%)和CIWI(34.56%);总体识别精度为82.00%,也大于MNDWI(58.00%)和CIWI(77.00%)。利用WZ5对遥感影像进行水体增强的方法 ,不仅能够很好地提取出湿地开阔水域的水体信息,边缘清晰可靠;对于破碎水域,WZ5水体提取精度最高,并且相比基于复杂数学理论的分类提取过程,操作相对简单,易于推广,能够较好地提高湿地水域实时监测的精度。展开更多
Saturated row-column designs are studied to eliminate positional effects in primary high- throughput screening experiments. Compared to designs currently used in practice, all compounds in the designs considered are c...Saturated row-column designs are studied to eliminate positional effects in primary high- throughput screening experiments. Compared to designs currently used in practice, all compounds in the designs considered are comparable within each microplate in spite of the existence of row and column effects. The designs considered in this paper also have the maximum number of compounds arranged in each microplate. Two statistical methods are used to choose leading compounds in the designs considered. These two methods take full advantages of effect sparsity in primary screening. Simulation studies are carried out to compare the two statistical methods with two ad hoc methods in selecting active compounds. A method that maintains balanced false positives and false negatives is recommended.展开更多
文摘湿地是"地球之肾",对地球生物生存具有重要意义。由于湿地水域面积的破碎化程度高,常规利用遥感技术提出的水体指数不够有效,简单快速的实时监测技术还需完善。以2009年杭州湾湿地的Landsat TM影像为基础数据,选择不同水域类型,构建新型水体指数(water zscore-band5,WZ5),与常用的改进的归一化差异水体指数(modified normalized difference water index,MNDWI),混合水体指数(combined index of NDVI and NIR for water body identification,CIWI)进行对比,分析各指数湿地水域信息提取的准确性和完整性。结果表明:所构建的指数WZ5水体信息提取精度优于MNDWI和CIWI,特别是含有大量塘基且分布复杂的水产池塘破碎区,WZ5计算水体与塘基的区分度为41.78%,大于MNDWI(21.59%)和CIWI(34.56%);总体识别精度为82.00%,也大于MNDWI(58.00%)和CIWI(77.00%)。利用WZ5对遥感影像进行水体增强的方法 ,不仅能够很好地提取出湿地开阔水域的水体信息,边缘清晰可靠;对于破碎水域,WZ5水体提取精度最高,并且相比基于复杂数学理论的分类提取过程,操作相对简单,易于推广,能够较好地提高湿地水域实时监测的精度。
文摘Saturated row-column designs are studied to eliminate positional effects in primary high- throughput screening experiments. Compared to designs currently used in practice, all compounds in the designs considered are comparable within each microplate in spite of the existence of row and column effects. The designs considered in this paper also have the maximum number of compounds arranged in each microplate. Two statistical methods are used to choose leading compounds in the designs considered. These two methods take full advantages of effect sparsity in primary screening. Simulation studies are carried out to compare the two statistical methods with two ad hoc methods in selecting active compounds. A method that maintains balanced false positives and false negatives is recommended.
