This study includes some aspects of the shift in the Dutch attitude in relation to water during the past millennia from defense to attack to keeping the balance(“co-evolution'). It has a special focus on the fres...This study includes some aspects of the shift in the Dutch attitude in relation to water during the past millennia from defense to attack to keeping the balance(“co-evolution'). It has a special focus on the freshwater tidal part, which embraces the largest seaport of the world: Rotterdam, as well as the largest national park of the Netherlands. It reports especially about a young mans endeavor in half a century real time monitoring of some land(scape) units with simple means.展开更多
差分隐私凭借其强大的隐私保护能力被应用在随机森林算法解决其中的隐私泄露问题,然而,直接将差分隐私应用在随机森林算法会使模型的分类准确率严重下降.为了平衡隐私保护和模型准确性之间的矛盾,提出了一种高效的差分隐私随机森林训练...差分隐私凭借其强大的隐私保护能力被应用在随机森林算法解决其中的隐私泄露问题,然而,直接将差分隐私应用在随机森林算法会使模型的分类准确率严重下降.为了平衡隐私保护和模型准确性之间的矛盾,提出了一种高效的差分隐私随机森林训练算法eDPRF(efficient differential privacy random forest).具体而言,该算法设计了决策树构建方法,通过引入重排翻转机制高效地查询输出优势,进一步设计相应的效用函数实现分裂特征以及标签的精准输出,有效改善树模型在扰动情况下对于数据信息的学习能力.同时基于组合定理设计了隐私预算分配的策略,通过不放回抽样获得训练子集以及差异化调整内部预算的方式提高树节点的查询预算.最后,通过理论分析以及实验评估,表明算法在给定相同隐私预算的情况下,模型的分类准确度优于同类算法.展开更多
In the context of global warming,apparent decdal-interdecdal variabilities can be detected in summer precipitation in southern China.Especially around the 1990 s,precipitation in South China experienced a phase transi...In the context of global warming,apparent decdal-interdecdal variabilities can be detected in summer precipitation in southern China.Especially around the 1990 s,precipitation in South China experienced a phase transition from a deficiency regime to an abundance regime in the early 1990 s,while the Yangtze River Valley witnessed a phase shift of summer precipitation from abundance to deficiency in the late 1990 s.Pertinent analyses reveal a close relationship between such decadal precipitation shifts and moisture budgets,which is mainly modulated by the meridional component.This relationship can be attributed to large-scale moisture transport anomalies.Further,the HYSPLIT model is utilized to quantitatively evaluate relative moisture contributions from diverse sources during different regimes.It can be found that during the period with abundant precipitation in South China,the moisture contribution from the source of Indochina Peninsula-South China Sea increased significantly,while during the deficient precipitation regime in the Yangtze River Valley,moisture from local source,western Pacific and Indochina Peninsula-South China Sea contributed less to precipitation.It means some new features of relative moisture contributions from diverse sources to precipitation anomaly in southern China took shape after 1990 s.展开更多
This paper develops an extended newsboy model and presents a formula- tion for this model. This new model has solved the budget contained multi-product newsboy problem with the reactive production. This model can be u...This paper develops an extended newsboy model and presents a formula- tion for this model. This new model has solved the budget contained multi-product newsboy problem with the reactive production. This model can be used to describe the status of entrepreneurial network construction. We use the Lagrange multiplier procedure to deal with our problem, but it is too complicated to get the exact solu-tion. So we introduce the homotopy method to deal with it. We give the flow chart to describe how to get the solution via the homotopy method. We also illustrate our model in both the classical procedure and the homotopy method. Comparing the two methods, we can see that the homotopy method is more exact and efficient.展开更多
Three approaches, i.e., the harmonic analysis （HA） technique, the thermal diffusion equation and correction （TDEC） method, and the calorimetric method used to estimate ground heat flux, are evaluated by using obse...Three approaches, i.e., the harmonic analysis （HA） technique, the thermal diffusion equation and correction （TDEC） method, and the calorimetric method used to estimate ground heat flux, are evaluated by using observations from the Semi-Arid Climate and Environment Observatory of Lanzhou University （SACOL） in July, 2008. The calorimetric method, which involves soil heat flux measurement with an HFP01SC self-calibrating heat flux plate buried at a depth of 5 cm and heat storage in the soil between the plate and the surface, is here called the ITHP approach. The results show good linear relationships between the soil heat fluxes measured with the HFP01SC heat flux plate and those calculated with the HA technique and the TDEC method, respectively, at a depth of 5 cm. The soil heat fluxes calculated with the latter two methods well follow the phase measured with the HFP01SC heat flux plate. The magnitudes of the soil heat flux calculated with the HA technique and the TDEC method are close to each other, and they are about 2 percent and 6 percent larger than the measured soil heat flux, respectively, which mainly occur during the nighttime. Moreover, the ground heat fluxes calculated with the TDEC method and the HA technique are highly correlated with each other （R2= 0.97）, and their difference is only about 1 percent. The TDEC-calculated ground heat flux also has a good linear relationship with the ITttP-calculated ground heat flux （R2 = 0.99）, but their difference is larger （about 9 percent）. Furthermore, compared to the HFP01SC direct measurements at a depth of 5 cm, the ground heat flux calculated with the HA technique, the TDEC method, and the ITHP approach can improve the surface energy budget closure by about 6 percent, 7 percent, and 6 percent at SACOL site, respectively. Therefore, the contribution of ground heat flux to the surface energy budget is very important for the semi-arid grassland over the Loess Plateau in China. Using turbulent heat fluxes with common corrections, soil heat storage between the surface and the heat flux plate can improve the surface energy budget closure by about 6 to 7 percent, resulting in a closure of 82 to 83 percent at the SACOL site.展开更多
文摘This study includes some aspects of the shift in the Dutch attitude in relation to water during the past millennia from defense to attack to keeping the balance(“co-evolution'). It has a special focus on the freshwater tidal part, which embraces the largest seaport of the world: Rotterdam, as well as the largest national park of the Netherlands. It reports especially about a young mans endeavor in half a century real time monitoring of some land(scape) units with simple means.
文摘差分隐私凭借其强大的隐私保护能力被应用在随机森林算法解决其中的隐私泄露问题,然而,直接将差分隐私应用在随机森林算法会使模型的分类准确率严重下降.为了平衡隐私保护和模型准确性之间的矛盾,提出了一种高效的差分隐私随机森林训练算法eDPRF(efficient differential privacy random forest).具体而言,该算法设计了决策树构建方法,通过引入重排翻转机制高效地查询输出优势,进一步设计相应的效用函数实现分裂特征以及标签的精准输出,有效改善树模型在扰动情况下对于数据信息的学习能力.同时基于组合定理设计了隐私预算分配的策略,通过不放回抽样获得训练子集以及差异化调整内部预算的方式提高树节点的查询预算.最后,通过理论分析以及实验评估,表明算法在给定相同隐私预算的情况下,模型的分类准确度优于同类算法.
基金National Basic Research and Development(973)Program of China(2013CB430202 and 2012CB417205)National Natural Science Foundation of China(41405071,41375091,41305131,41461164006)Key Projects of Scientific and Technological Research of Southern China Regional Meteorological Center(GRMC2014Z01)
文摘In the context of global warming,apparent decdal-interdecdal variabilities can be detected in summer precipitation in southern China.Especially around the 1990 s,precipitation in South China experienced a phase transition from a deficiency regime to an abundance regime in the early 1990 s,while the Yangtze River Valley witnessed a phase shift of summer precipitation from abundance to deficiency in the late 1990 s.Pertinent analyses reveal a close relationship between such decadal precipitation shifts and moisture budgets,which is mainly modulated by the meridional component.This relationship can be attributed to large-scale moisture transport anomalies.Further,the HYSPLIT model is utilized to quantitatively evaluate relative moisture contributions from diverse sources during different regimes.It can be found that during the period with abundant precipitation in South China,the moisture contribution from the source of Indochina Peninsula-South China Sea increased significantly,while during the deficient precipitation regime in the Yangtze River Valley,moisture from local source,western Pacific and Indochina Peninsula-South China Sea contributed less to precipitation.It means some new features of relative moisture contributions from diverse sources to precipitation anomaly in southern China took shape after 1990 s.
文摘This paper develops an extended newsboy model and presents a formula- tion for this model. This new model has solved the budget contained multi-product newsboy problem with the reactive production. This model can be used to describe the status of entrepreneurial network construction. We use the Lagrange multiplier procedure to deal with our problem, but it is too complicated to get the exact solu-tion. So we introduce the homotopy method to deal with it. We give the flow chart to describe how to get the solution via the homotopy method. We also illustrate our model in both the classical procedure and the homotopy method. Comparing the two methods, we can see that the homotopy method is more exact and efficient.
基金supported by the National Natural Science Foundation of China (GrantNo. 40725015)
文摘Three approaches, i.e., the harmonic analysis （HA） technique, the thermal diffusion equation and correction （TDEC） method, and the calorimetric method used to estimate ground heat flux, are evaluated by using observations from the Semi-Arid Climate and Environment Observatory of Lanzhou University （SACOL） in July, 2008. The calorimetric method, which involves soil heat flux measurement with an HFP01SC self-calibrating heat flux plate buried at a depth of 5 cm and heat storage in the soil between the plate and the surface, is here called the ITHP approach. The results show good linear relationships between the soil heat fluxes measured with the HFP01SC heat flux plate and those calculated with the HA technique and the TDEC method, respectively, at a depth of 5 cm. The soil heat fluxes calculated with the latter two methods well follow the phase measured with the HFP01SC heat flux plate. The magnitudes of the soil heat flux calculated with the HA technique and the TDEC method are close to each other, and they are about 2 percent and 6 percent larger than the measured soil heat flux, respectively, which mainly occur during the nighttime. Moreover, the ground heat fluxes calculated with the TDEC method and the HA technique are highly correlated with each other （R2= 0.97）, and their difference is only about 1 percent. The TDEC-calculated ground heat flux also has a good linear relationship with the ITttP-calculated ground heat flux （R2 = 0.99）, but their difference is larger （about 9 percent）. Furthermore, compared to the HFP01SC direct measurements at a depth of 5 cm, the ground heat flux calculated with the HA technique, the TDEC method, and the ITHP approach can improve the surface energy budget closure by about 6 percent, 7 percent, and 6 percent at SACOL site, respectively. Therefore, the contribution of ground heat flux to the surface energy budget is very important for the semi-arid grassland over the Loess Plateau in China. Using turbulent heat fluxes with common corrections, soil heat storage between the surface and the heat flux plate can improve the surface energy budget closure by about 6 to 7 percent, resulting in a closure of 82 to 83 percent at the SACOL site.
