Shanghai has experienced the greatest land subsidence in China in the past sixty years and produced undesirable environmental impact. However, horizontal ground deformation has not been understood yet. Therefore groun...Shanghai has experienced the greatest land subsidence in China in the past sixty years and produced undesirable environmental impact. However, horizontal ground deformation has not been understood yet. Therefore ground deformation monitoring together with the analysis of its driving forces are critical for geo-hazards early-warning, city planning and sustainable urbanization in Shanghai. In this paper, two-dimensional ground deformation monitoring was performed in Shanghai with SBAS and MSBAS InSAR methods. Twenty-nine Multi-Look Fine 6 （MF6） Radarsat-2 SLC data acquired during 2011-2013 were used to derive vertical ground deformation. Meanwhile, six descending Multi-Look Fine 6 （MF6） and four ascending Multi-Look Fine 2 （MF2） spanning April to August, 2008, were used to derive vertical and horizontal ground deformation during the observation period. The results indicate that vertical and horizontal deformations in 2008 were not homogeneously distributed in different districts ranging from 0-2 cm/year. Vertical deformation rate during 2011-2013 were decreased to less than 1 cm/year in most district of Shanghai area. Activities from groundwater exploitation and rapid urbanization are responsible for most of the ground deformation in Shanghai. Thus, future ground deformation in vertical and horizontal directions should be warranted.展开更多
Intermittent demand refers to the specific demand pattern with frequent periods of zero demand.It occurs in a variety of industries including industrial equipment,automotive and specialty chemicals.In some industries ...Intermittent demand refers to the specific demand pattern with frequent periods of zero demand.It occurs in a variety of industries including industrial equipment,automotive and specialty chemicals.In some industries or some sectors of industry,even majority of products are in intermittent demand pattern.Due to the usually small and highly variable demand sizes,accurate forecasting of intermittent demand has always been challenging.However,accurate forecasting of intermittent demand is critical to the effective inventory management.In this study we present a band new method-modified TSB method for the forecasting of intermittent demand.The proposed method is based on TSB method,and adopts similar strategy,which has been used in m SBA method to update demand interval and demand occurrence probability when current demand is zero.To evaluate the proposed method,16289 daily demand records from the M5 data set that are identified as intermittent demands according to two criteria,and an empirical data set consisting three years’monthly demand history of 1718 medicine products are used.The proposed m TSB method achieves the best results on MASE and RMASE among all comparison methods on the M5 data set.On the empirical data set,the study shows that m TSB attains an ME of 0.07,which is the best among six comparison methods.Additionally,on the MSE measurement,m TSB shows a similar result as SES,both of which outperform other methods.展开更多
基金supported by the China Science National Foundation (No. 41372353)
文摘Shanghai has experienced the greatest land subsidence in China in the past sixty years and produced undesirable environmental impact. However, horizontal ground deformation has not been understood yet. Therefore ground deformation monitoring together with the analysis of its driving forces are critical for geo-hazards early-warning, city planning and sustainable urbanization in Shanghai. In this paper, two-dimensional ground deformation monitoring was performed in Shanghai with SBAS and MSBAS InSAR methods. Twenty-nine Multi-Look Fine 6 （MF6） Radarsat-2 SLC data acquired during 2011-2013 were used to derive vertical ground deformation. Meanwhile, six descending Multi-Look Fine 6 （MF6） and four ascending Multi-Look Fine 2 （MF2） spanning April to August, 2008, were used to derive vertical and horizontal ground deformation during the observation period. The results indicate that vertical and horizontal deformations in 2008 were not homogeneously distributed in different districts ranging from 0-2 cm/year. Vertical deformation rate during 2011-2013 were decreased to less than 1 cm/year in most district of Shanghai area. Activities from groundwater exploitation and rapid urbanization are responsible for most of the ground deformation in Shanghai. Thus, future ground deformation in vertical and horizontal directions should be warranted.
基金supported in part by XJTLU laboratory for intelligent computation and financial technology through XJTLU Key Programme Special Fund(KSFeP-02 and KSF-E-21)
文摘Intermittent demand refers to the specific demand pattern with frequent periods of zero demand.It occurs in a variety of industries including industrial equipment,automotive and specialty chemicals.In some industries or some sectors of industry,even majority of products are in intermittent demand pattern.Due to the usually small and highly variable demand sizes,accurate forecasting of intermittent demand has always been challenging.However,accurate forecasting of intermittent demand is critical to the effective inventory management.In this study we present a band new method-modified TSB method for the forecasting of intermittent demand.The proposed method is based on TSB method,and adopts similar strategy,which has been used in m SBA method to update demand interval and demand occurrence probability when current demand is zero.To evaluate the proposed method,16289 daily demand records from the M5 data set that are identified as intermittent demands according to two criteria,and an empirical data set consisting three years’monthly demand history of 1718 medicine products are used.The proposed m TSB method achieves the best results on MASE and RMASE among all comparison methods on the M5 data set.On the empirical data set,the study shows that m TSB attains an ME of 0.07,which is the best among six comparison methods.Additionally,on the MSE measurement,m TSB shows a similar result as SES,both of which outperform other methods.
