Long-term experiments can be used to assess management induced changes in soil properties and sustainability of the management system in terms of the productivity. Such data are scanty, especially in the semi-arid tro...Long-term experiments can be used to assess management induced changes in soil properties and sustainability of the management system in terms of the productivity. Such data are scanty, especially in the semi-arid tropics (SAT) region. A long-term experiment established in 1976 at ICRISAT in India on Vertisols with two management treatments;improved management (IM), comprising semi-permanent broadbed and furrow (BBF) landform with minimum tillage and improved cropping practices;and traditional management (TM) system comprising keeping the land fallow during the rainy season and sowing on flat landform during post-rainy season with traditional cropping practices, was sampled after 24 and 34 years for soil physical and hydrological properties. Results showed that both in short-and long-term the management systems had profound effect on crop yields. Also in the long-term IM and TM management systems had significant effect on several soil physical and hydrological properties. Throughout the soil profile IM systems had significantly lower bulk density, significantly higher porosity, substantially lower penetration resistance both at 5 cm (1 and 8 MPa) and 15 cm depths (8 and 15 MPa), significantly higher infiltration and sorptivity and significantly larger mean weight diameter of 4.3 mm compared to 2.8 mm for soils under TM. However, management systems had no significant effect on moisture holding capacities both at 0.033 and 1.5 MPa. Significant differences between the improved and traditional systems were observed in the size and pattern of soil surface cracks. Over the long-term, the improved management systems has very favorable effects on soil physical and hydrological properties and on the soil surface cracking and its patterns, thereby contributing to higher productivity.展开更多
该文引入信息理论分析电力系统的负荷预测以及可再生能源出力预测,将其描述为信息决策过程,并提出了短期负荷预测中的最小信息损失(minimization of information loss,MIL)综合模型,利用历史负荷与预测误差的分布情况在信息损失最小的...该文引入信息理论分析电力系统的负荷预测以及可再生能源出力预测,将其描述为信息决策过程,并提出了短期负荷预测中的最小信息损失(minimization of information loss,MIL)综合模型,利用历史负荷与预测误差的分布情况在信息损失最小的原则下求解最可能的负荷取值。针对MIL综合模型中概率分布的估计问题,文中应用了正态分布参数估计和Parzen窗估计2种不同的方法,给出了各自的算法和实现方案。算例部分通过用实际电网负荷数据和实际风力发电出力数据进行测试,研究了MIL综合模型结构与参数对预测结果的影响,并在与传统综合模型的比较中显示了新模型的优越性。展开更多
该文引入信息理论分析电力系统的负荷预测,将其描述为信息决策过程,并提出了短期负荷预测中的最小信息损失(minimization of information loss,MIL)综合模型,利用历史负荷与预测误差的分布情况在信息损失最小的原则下求解最可能的负荷...该文引入信息理论分析电力系统的负荷预测,将其描述为信息决策过程,并提出了短期负荷预测中的最小信息损失(minimization of information loss,MIL)综合模型,利用历史负荷与预测误差的分布情况在信息损失最小的原则下求解最可能的负荷取值。针对MIL综合模型中概率分布的估计问题,文中应用了正态分布参数估计和Parzen窗估计2种不同的方法,给出了各自的算法。展开更多
文摘Long-term experiments can be used to assess management induced changes in soil properties and sustainability of the management system in terms of the productivity. Such data are scanty, especially in the semi-arid tropics (SAT) region. A long-term experiment established in 1976 at ICRISAT in India on Vertisols with two management treatments;improved management (IM), comprising semi-permanent broadbed and furrow (BBF) landform with minimum tillage and improved cropping practices;and traditional management (TM) system comprising keeping the land fallow during the rainy season and sowing on flat landform during post-rainy season with traditional cropping practices, was sampled after 24 and 34 years for soil physical and hydrological properties. Results showed that both in short-and long-term the management systems had profound effect on crop yields. Also in the long-term IM and TM management systems had significant effect on several soil physical and hydrological properties. Throughout the soil profile IM systems had significantly lower bulk density, significantly higher porosity, substantially lower penetration resistance both at 5 cm (1 and 8 MPa) and 15 cm depths (8 and 15 MPa), significantly higher infiltration and sorptivity and significantly larger mean weight diameter of 4.3 mm compared to 2.8 mm for soils under TM. However, management systems had no significant effect on moisture holding capacities both at 0.033 and 1.5 MPa. Significant differences between the improved and traditional systems were observed in the size and pattern of soil surface cracks. Over the long-term, the improved management systems has very favorable effects on soil physical and hydrological properties and on the soil surface cracking and its patterns, thereby contributing to higher productivity.
文摘该文引入信息理论分析电力系统的负荷预测以及可再生能源出力预测,将其描述为信息决策过程,并提出了短期负荷预测中的最小信息损失(minimization of information loss,MIL)综合模型,利用历史负荷与预测误差的分布情况在信息损失最小的原则下求解最可能的负荷取值。针对MIL综合模型中概率分布的估计问题,文中应用了正态分布参数估计和Parzen窗估计2种不同的方法,给出了各自的算法和实现方案。算例部分通过用实际电网负荷数据和实际风力发电出力数据进行测试,研究了MIL综合模型结构与参数对预测结果的影响,并在与传统综合模型的比较中显示了新模型的优越性。
文摘该文引入信息理论分析电力系统的负荷预测,将其描述为信息决策过程,并提出了短期负荷预测中的最小信息损失(minimization of information loss,MIL)综合模型,利用历史负荷与预测误差的分布情况在信息损失最小的原则下求解最可能的负荷取值。针对MIL综合模型中概率分布的估计问题,文中应用了正态分布参数估计和Parzen窗估计2种不同的方法,给出了各自的算法。
