For this research work, an adequate methodology was sought for the calculation of the runoff coefficient with the Tirado arrangement. To achieve this, first, the variables that affect the runoff coefficient were ident...For this research work, an adequate methodology was sought for the calculation of the runoff coefficient with the Tirado arrangement. To achieve this, first, the variables that affect the runoff coefficient were identified, then the model was described with the Tirado arrangement, and as a third part for the calculation of the runoff coefficient, the Tirado model is proposed. From the theory for the calculation of the runoff coefficient, the equation of the weighted coefficients and the expression of Nadal were manipulated, resulting in the following relationship , considering this as the expression for the arrangement Tirado. The expression is tested with different intensities, the magnitudes correspond to 150, 200, 250 and 300 mm/hrs, resulting in runoff coefficient 0.82, 0.87, 0.89, 0.91 respectively. This means that, the higher the intensity, the runoff coefficient will be higher, logically the characteristics of the basin affect that this coefficient has variation in the space studied.展开更多
It is important to understand the relationship between the ambient ebb and flood currents and the electricity generated by tidal stream power generators to minimise investment risk and to optimise power generation for...It is important to understand the relationship between the ambient ebb and flood currents and the electricity generated by tidal stream power generators to minimise investment risk and to optimise power generation for distribution purposes. Such analyses no longer rely on average descriptions of the flow field or on single values for the device efficiency. In the present paper, we demonstrate a new method involving the integration of synthesised long termflow vectors with logistic descriptions of the device power curves. New experiments are then described with the Neptune Proteus vertical axis tidal stream power generator involving tow tests at speeds to 1.5 ms–1 in William Wright Dock on the Humber. The results are used to derive appropriate coefficients in the logisticcurve and to estimate the device’s annual electrical output.展开更多
Reference control points (RCPs) used in establishing the regression model in the regis-tration or geometric correction of remote sensing images are generally assumed to be “perfect”. That is, the RCPs, as explanator...Reference control points (RCPs) used in establishing the regression model in the regis-tration or geometric correction of remote sensing images are generally assumed to be “perfect”. That is, the RCPs, as explanatory variables in the regression equation, are accurate and the coordinates of their locations have no errors. Thus ordinary least squares (OLS) estimator has been applied exten-sively to the registration or geometric correction of remotely sensed data. However, this assumption is often invalid in practice because RCPs always contain errors. Moreover, the errors are actually one of the main sources which lower the accuracy of geometric correction of an uncorrected image. Under this situation, the OLS estimator is biased. It cannot handle explanatory variables with errors and cannot propagate appropriately errors from the RCPs to the corrected image. Therefore, it is essential to develop new feasible methods to overcome such a problem. This paper introduces a consistent adjusted least squares (CALS) estimator and proposes relaxed consistent adjusted least squares (RCALS) estimator, with the latter being more general and flexible, for geometric correction or regis-tration. These estimators have good capability in correcting errors contained in the RCPs, and in propagating appropriately errors of the RCPs to the corrected image with and without prior information. The objective of the CALS and proposed RCALS estimators is to improve the accuracy of measure-ment value by weakening the measurement errors. The conceptual arguments are substantiated by a real remotely sensed data. Compared to the OLS estimator, the CALS and RCALS estimators give a superior overall performance in estimating the regression coefficients and variance of measurement errors.展开更多
Previous research that reported the linkage between climate change and plague activity primarily refers to the immediate effect of short-term climatic variation. Yet, decades of discussion about the climate-plague ass...Previous research that reported the linkage between climate change and plague activity primarily refers to the immediate effect of short-term climatic variation. Yet, decades of discussion about the climate-plague association cannot determine the precise role of climate in shaping plague dynamics. One reason for this discrepancy originates from the narrow selection of spatio-temporal settings for comprehensive analysis of the correlation, leading to a limited consideration of the complexity of possible dynamics.By analyzing a 414-year long record of plague outbreak in pre-industrial Europe and the corresponding climatic data in multi-scale,we find little evidence to support climate-plague correlation in(1) both climatic variations and large-scale climatic phenomena,(2)both country scale and continental scale,(3) annual to inter-annual scale, and(4) both linear and non-linear analytic approaches. The null-result should not be viewed as a general rejection of other recent findings related to climate-plague association; nevertheless,it suggests that a wider consideration of scales, sensitivity checks and consideration of contexts should be included in explaining and predicting plague transmission under contemporary global climate conditions.展开更多
文摘For this research work, an adequate methodology was sought for the calculation of the runoff coefficient with the Tirado arrangement. To achieve this, first, the variables that affect the runoff coefficient were identified, then the model was described with the Tirado arrangement, and as a third part for the calculation of the runoff coefficient, the Tirado model is proposed. From the theory for the calculation of the runoff coefficient, the equation of the weighted coefficients and the expression of Nadal were manipulated, resulting in the following relationship , considering this as the expression for the arrangement Tirado. The expression is tested with different intensities, the magnitudes correspond to 150, 200, 250 and 300 mm/hrs, resulting in runoff coefficient 0.82, 0.87, 0.89, 0.91 respectively. This means that, the higher the intensity, the runoff coefficient will be higher, logically the characteristics of the basin affect that this coefficient has variation in the space studied.
文摘It is important to understand the relationship between the ambient ebb and flood currents and the electricity generated by tidal stream power generators to minimise investment risk and to optimise power generation for distribution purposes. Such analyses no longer rely on average descriptions of the flow field or on single values for the device efficiency. In the present paper, we demonstrate a new method involving the integration of synthesised long termflow vectors with logistic descriptions of the device power curves. New experiments are then described with the Neptune Proteus vertical axis tidal stream power generator involving tow tests at speeds to 1.5 ms–1 in William Wright Dock on the Humber. The results are used to derive appropriate coefficients in the logisticcurve and to estimate the device’s annual electrical output.
基金This work was supported in part by the National'973'Program(Grant No.2006CB701305)the National Natural Science Foundation of China(Grant No.40201033)the Knowledge Innovation Project of the Chinese Academy of Sciences(V36400).
文摘Reference control points (RCPs) used in establishing the regression model in the regis-tration or geometric correction of remote sensing images are generally assumed to be “perfect”. That is, the RCPs, as explanatory variables in the regression equation, are accurate and the coordinates of their locations have no errors. Thus ordinary least squares (OLS) estimator has been applied exten-sively to the registration or geometric correction of remotely sensed data. However, this assumption is often invalid in practice because RCPs always contain errors. Moreover, the errors are actually one of the main sources which lower the accuracy of geometric correction of an uncorrected image. Under this situation, the OLS estimator is biased. It cannot handle explanatory variables with errors and cannot propagate appropriately errors from the RCPs to the corrected image. Therefore, it is essential to develop new feasible methods to overcome such a problem. This paper introduces a consistent adjusted least squares (CALS) estimator and proposes relaxed consistent adjusted least squares (RCALS) estimator, with the latter being more general and flexible, for geometric correction or regis-tration. These estimators have good capability in correcting errors contained in the RCPs, and in propagating appropriately errors of the RCPs to the corrected image with and without prior information. The objective of the CALS and proposed RCALS estimators is to improve the accuracy of measure-ment value by weakening the measurement errors. The conceptual arguments are substantiated by a real remotely sensed data. Compared to the OLS estimator, the CALS and RCALS estimators give a superior overall performance in estimating the regression coefficients and variance of measurement errors.
基金supported by the Hui Oi-Chow Trust Fund (Grant Nos. 201502172003 & 201602172006)Research Grants Council of The Government of the Hong Kong Special Administrative Region of the People’s Republic of China (Grant Nos. HKU745113H & 17610715)
文摘Previous research that reported the linkage between climate change and plague activity primarily refers to the immediate effect of short-term climatic variation. Yet, decades of discussion about the climate-plague association cannot determine the precise role of climate in shaping plague dynamics. One reason for this discrepancy originates from the narrow selection of spatio-temporal settings for comprehensive analysis of the correlation, leading to a limited consideration of the complexity of possible dynamics.By analyzing a 414-year long record of plague outbreak in pre-industrial Europe and the corresponding climatic data in multi-scale,we find little evidence to support climate-plague correlation in(1) both climatic variations and large-scale climatic phenomena,(2)both country scale and continental scale,(3) annual to inter-annual scale, and(4) both linear and non-linear analytic approaches. The null-result should not be viewed as a general rejection of other recent findings related to climate-plague association; nevertheless,it suggests that a wider consideration of scales, sensitivity checks and consideration of contexts should be included in explaining and predicting plague transmission under contemporary global climate conditions.
