[Objective] The aim was to explore the measurement methods of drawdown of motor-pumped well in land consolidation. [Method] Based on pumping information, the relation curve of drawdown and pumped volume was drawn and ...[Objective] The aim was to explore the measurement methods of drawdown of motor-pumped well in land consolidation. [Method] Based on pumping information, the relation curve of drawdown and pumped volume was drawn and the empirical formula was concluded, with examples. [Result] The type of drawdown （h） and flow volume （Q） includes linear type, parabolic type, exponential curve and logarithmic curve. Graphical method and calculus of differences are available for determining the type of curve. [Conclusion] The empirical formula based on pumping test reflects relation between drawdown and pumping volume, which is simple and effective.展开更多
Active velocity tomography was used to determine the stress state and rock burst hazards in a deep coal mine. The deepest longwall face, number 3207 in the Xingcun colliery, was the location of the field trials. The p...Active velocity tomography was used to determine the stress state and rock burst hazards in a deep coal mine. The deepest longwall face, number 3207 in the Xingcun colliery, was the location of the field trials. The positive correlation between stress and seismic velocity was used to link the velocity data with stratum stresses. A GeoPen SE2404NT data acquisition system was used to collect seismic data from 300 g explosive charges fired by instantaneous electric detonator and located in the tail entry. The geophones were installed on the rock bolts in the head entry of LW3207. Velocity inversion shows an inhomogeneous distribution of stress in the longvvall face that could not be obtained from theory or numerical simulations. Three abnormally high P-wave velocity regions were identified that were located on the corners of the two roadways and at the face end near the rail entry side. The maximum velocity gradient is located at the open cut off near the rail entry and is the area most dangerous for rock burst. Mining-induced tremors recorded by a micro-seismic monitoring system demonstrated that the position of energy release during mining coincides with the high velocity gradient area. This technology aids technicians in the coal mine as they design measures to weaken or eliminate potential danger during subsequent mining.展开更多
To accurately analyze the fluctuation range of time-varying differences in metro-to-bus transfer passenger flows,the application of a probabilistic interval prediction model is proposed to predict transfer passenger f...To accurately analyze the fluctuation range of time-varying differences in metro-to-bus transfer passenger flows,the application of a probabilistic interval prediction model is proposed to predict transfer passenger flows.First,bus and metro data are processed and matched by association to construct the basis for public transport trip chain extraction.Second,a reasonable matching threshold method to discriminate the transfer relationship is used to extract the public transport trip chain,and the basic characteristics of the trip based on the trip chain are analyzed to obtain the metro-to-bus transfer passenger flow.Third,to address the problem of low accuracy of point prediction,the DeepAR model is proposed to conduct interval prediction,where the input is the interchange passenger flow,the output is the predicted median and interval of passenger flow,and the prediction scenarios are weekday,non-workday,and weekday morning and evening peaks.Fourth,to reduce the prediction error,a combined particle swarm optimization(PSO)-DeepAR model is constructed using the PSO to optimize the DeepAR model.Finally,data from the Beijing Xizhimen subway station are used for validation,and results show that the PSO-DeepAR model has high prediction accuracy,with a 90%confidence interval coverage of up to 93.6%.展开更多
To solve the dimensional limitations of physical models in tests, an equivalent water depth truncated design for a classical SPAR working in 913 m water was investigated. The water depth was reduced to 736m and then t...To solve the dimensional limitations of physical models in tests, an equivalent water depth truncated design for a classical SPAR working in 913 m water was investigated. The water depth was reduced to 736m and then to 552m. As this was done, the mooting line lengths, EA value, and mass per meter were adjusted. Truncation rules and formulas for parameters and truncation factors were proposed. SPAR static characteristics were made to be consistent with those at full water depth. Then further time-domain coupled analysis was carried out for the SPAR when the mooting system experienced waves. The mooring lines were simulated by quasi-static method. Global responses and mooring line forces were found to agree well with test results for a prototype at that water depth. The truncation method proved to be robust and reliable.展开更多
China's newly enacted Breakwater Design Specifications(JTS154-2011) explicitly state that breakwaters with water depths greater than 20 m are categorized as deep-water breakwaters, and emphasize that design princi...China's newly enacted Breakwater Design Specifications(JTS154-2011) explicitly state that breakwaters with water depths greater than 20 m are categorized as deep-water breakwaters, and emphasize that design principles, methods and construction requirements are different from those of common shallow water breakwaters. However, the specifications do not make any mention of how to choose wave force calculation methods of deep-water breakwaters. To study the feasibility of different formulae for wave force estimation of deep water combined breakwaters, the wave force calculated by the Sainflou's, Goda's, modified Goda's and specifications' methods are compared for various water depths and wave heights in this paper. The calculated results are also compared with experimental data. The total horizontal forcing and the pattern of pressure distributions are presented. Comparisons show that the wave pressure distributions by the four methods are similar, but the total horizontal forces are different. The results obtained by the Goda's method and the specified formulae are much closer to the experimental data. As for the wave force estimation for the deepwater mixed embankment foundation bed parapet, the Goda's formula is applied in the case with a water depth of less than 42 m. The Specifications method is suitable for standing waves. In the wave force estimates of breastworks, Sainflou's and the modified Gaoda's formulae are no longer applicable for the foundation bed of mixed embankment.展开更多
This study empirically investigates the impact of managerial entrenchment on firm financial performance of Chinese firms initial public offerings （IPOs）. Using 142 firms listed in the Shenzhen Stock Exchange （SZSE...This study empirically investigates the impact of managerial entrenchment on firm financial performance of Chinese firms initial public offerings （IPOs）. Using 142 firms listed in the Shenzhen Stock Exchange （SZSE）, which was collected from the Guotaian Research Service Center （GTA-RSC） databases, this study uses two proxies to measure firm performance and three proxies to measure managerial entrenchment. The two proxies for firm performance are Tobins＇ Q and return on assets （ROA）, and the three proxies for managerial entrenchment are entrenchment 1, entrenchment 2, and entrenchment 3. These three entrenchment proxies are derived from the principal component analysis （PCA）. Though previous studies of managerial entrenchment and firm performance variables suffer from endogeneity, with respect to the corporate governance it is unclear as to which variables are endogenous and which are exogenous. This study confirms that the data are linear and no endogeneity issue should be address in this study, but only heteroskedasticity, non-normality for Tobins＇ Q are a problem, therefore, the regression method employed for Tobins＇ Q is the generalised least square （GLS） and the ordinary least square （OLS） between estimators for ROA. The regression result for Tobins＇ Q reveals that managerial entrenchment is negatively impact on firm performance. The results are in contradiction to the stewardship theory for new firms whereas the managerial entrenchment for new firms is positive. Furthermore, only one entrenchment proxy yields a significant coefficient. In conclusion, the negative results of entrenchment proxies were caused by the different institutional structures and legal systems which are the Chinese corporations that are still largely owned and controlled by a state and hence the centralised state controlled was responsible for all managerial actions.展开更多
In recent years, managers＇ self-interest motivation has been attracting more and more attention from both the academia and practice.Therefore, the ways and depth of managers＇ self-interest motivation influencing lis...In recent years, managers＇ self-interest motivation has been attracting more and more attention from both the academia and practice.Therefore, the ways and depth of managers＇ self-interest motivation influencing listed companies＇ operating performance has become a hot research area with important theoretical and practical significance. Based on the samples of A-share companies listed in Shanghai and Shenzhen stock exchange during 2012-2014. we studied different effects of managers＇ self-interest motivation on listed company＇s business performance under different situations.The innovation of this paper mainly lies in the following two points： on the one hand, we did not adopt the previous research methods which does not distinguish different kinds of company＇s business performance. Therefore, we divided business performance into two types firstly, then we made empirical text of the influences of managers＇ self-interest motivation on business performance by virtue of Hausman Model and drew related conclusions under different situations of operating performance. On the other hand, the index measuring managers＇ self-interest is relatively new.展开更多
Logistics industry has become the driving force of economic growth. However, the logistics industry develops very slowly because the institutional factors have critically hindered the whole development of logistics in...Logistics industry has become the driving force of economic growth. However, the logistics industry develops very slowly because the institutional factors have critically hindered the whole development of logistics industry in China. Institutional factors are regarded as the important factor for logistics cost under the market segmentation of peasant mentality. By comparison of the institutional costs in United States, Japan, India and the Europe, deep reason of high cost behind cost driving force is analyzed. Countermeasure is put forward, such as reducing the prices of domestic toll road, using fuel tax as implemented for highway construction funds, and decreasing the restricted policy for carrying freight cars etc..展开更多
Four urban greenbelt types including roadside greenbelt, resident-area greenbelt, landscape forest, and forest park, were simultaneously investigated in Shenzhen, China, in such measures as air temperature, air humidi...Four urban greenbelt types including roadside greenbelt, resident-area greenbelt, landscape forest, and forest park, were simultaneously investigated in Shenzhen, China, in such measures as air temperature, air humidity, wind speed, air anion ratio, and inhalabal particle concentration, which were strongly related with pleasing feeling of human body. The results show that the average air temperature in both forest park and landscape forest is much closer to the pleasing feeling of human body temperature than that of the rest two greenbelts, where it is 1.782 ℃ and 0.837℃ in forest park as well as 3.084 ℃ and 2.140 ℃ in landscape forest less than that of roadside and resident-area greenbelts, respectively. In terms of mean air humidity, forest park and landscape forest are 3.034% and 7.563% higher than that of roadside greenbelt, and 1.205% and 5.734% higher than that of resident-area greenbelt, respectively, implying a sound humidity feeling of human comfort in the former two types. The air cleanness holds a descending rank as forest park, landscape forest, resident-area greenbelt, and roadside greenbelt, whereas the rank in inhalable particle concentration is completely reverse. In general, landscape forest and forest park that mainly consist of trees have a comparatively higher feeling of human comfort whereas roadside and resident-area greenbelts fluctuate irregularly to some extent for the measures studied. The four greenbelt types investigated could be summarized in human comfort as the following descending rank, forest park, landscape forest, resident-area greenbelt, and roadside greenbelt.展开更多
文摘[Objective] The aim was to explore the measurement methods of drawdown of motor-pumped well in land consolidation. [Method] Based on pumping information, the relation curve of drawdown and pumped volume was drawn and the empirical formula was concluded, with examples. [Result] The type of drawdown （h） and flow volume （Q） includes linear type, parabolic type, exponential curve and logarithmic curve. Graphical method and calculus of differences are available for determining the type of curve. [Conclusion] The empirical formula based on pumping test reflects relation between drawdown and pumping volume, which is simple and effective.
基金support for this work was provided by the National Basic Research Program of China (No. 2010CB226805)the National Natural Science Foundation of China (Nos. 50474068 and50490273)+1 种基金the Independent Foundation of State Key Laboratory of Coal Resources and Mine Safety (No. SKLCRSM10X05)the Open Foundation of State Key Laboratory of Coal Resources and Mine Safety (No. 10KF05)
文摘Active velocity tomography was used to determine the stress state and rock burst hazards in a deep coal mine. The deepest longwall face, number 3207 in the Xingcun colliery, was the location of the field trials. The positive correlation between stress and seismic velocity was used to link the velocity data with stratum stresses. A GeoPen SE2404NT data acquisition system was used to collect seismic data from 300 g explosive charges fired by instantaneous electric detonator and located in the tail entry. The geophones were installed on the rock bolts in the head entry of LW3207. Velocity inversion shows an inhomogeneous distribution of stress in the longvvall face that could not be obtained from theory or numerical simulations. Three abnormally high P-wave velocity regions were identified that were located on the corners of the two roadways and at the face end near the rail entry side. The maximum velocity gradient is located at the open cut off near the rail entry and is the area most dangerous for rock burst. Mining-induced tremors recorded by a micro-seismic monitoring system demonstrated that the position of energy release during mining coincides with the high velocity gradient area. This technology aids technicians in the coal mine as they design measures to weaken or eliminate potential danger during subsequent mining.
基金The National Key Research and Development Program of China(No.2019YFB160-0200)the National Natural Science Foundation of China(No.71871011,71890972/71890970)。
文摘To accurately analyze the fluctuation range of time-varying differences in metro-to-bus transfer passenger flows,the application of a probabilistic interval prediction model is proposed to predict transfer passenger flows.First,bus and metro data are processed and matched by association to construct the basis for public transport trip chain extraction.Second,a reasonable matching threshold method to discriminate the transfer relationship is used to extract the public transport trip chain,and the basic characteristics of the trip based on the trip chain are analyzed to obtain the metro-to-bus transfer passenger flow.Third,to address the problem of low accuracy of point prediction,the DeepAR model is proposed to conduct interval prediction,where the input is the interchange passenger flow,the output is the predicted median and interval of passenger flow,and the prediction scenarios are weekday,non-workday,and weekday morning and evening peaks.Fourth,to reduce the prediction error,a combined particle swarm optimization(PSO)-DeepAR model is constructed using the PSO to optimize the DeepAR model.Finally,data from the Beijing Xizhimen subway station are used for validation,and results show that the PSO-DeepAR model has high prediction accuracy,with a 90%confidence interval coverage of up to 93.6%.
基金Supported by China National 111 Project Under Grant No.B07019
文摘To solve the dimensional limitations of physical models in tests, an equivalent water depth truncated design for a classical SPAR working in 913 m water was investigated. The water depth was reduced to 736m and then to 552m. As this was done, the mooting line lengths, EA value, and mass per meter were adjusted. Truncation rules and formulas for parameters and truncation factors were proposed. SPAR static characteristics were made to be consistent with those at full water depth. Then further time-domain coupled analysis was carried out for the SPAR when the mooting system experienced waves. The mooring lines were simulated by quasi-static method. Global responses and mooring line forces were found to agree well with test results for a prototype at that water depth. The truncation method proved to be robust and reliable.
基金supported by the Shandong Sci-tech Development Plan(Item No.2008GGB01099)
文摘China's newly enacted Breakwater Design Specifications(JTS154-2011) explicitly state that breakwaters with water depths greater than 20 m are categorized as deep-water breakwaters, and emphasize that design principles, methods and construction requirements are different from those of common shallow water breakwaters. However, the specifications do not make any mention of how to choose wave force calculation methods of deep-water breakwaters. To study the feasibility of different formulae for wave force estimation of deep water combined breakwaters, the wave force calculated by the Sainflou's, Goda's, modified Goda's and specifications' methods are compared for various water depths and wave heights in this paper. The calculated results are also compared with experimental data. The total horizontal forcing and the pattern of pressure distributions are presented. Comparisons show that the wave pressure distributions by the four methods are similar, but the total horizontal forces are different. The results obtained by the Goda's method and the specified formulae are much closer to the experimental data. As for the wave force estimation for the deepwater mixed embankment foundation bed parapet, the Goda's formula is applied in the case with a water depth of less than 42 m. The Specifications method is suitable for standing waves. In the wave force estimates of breastworks, Sainflou's and the modified Gaoda's formulae are no longer applicable for the foundation bed of mixed embankment.
文摘This study empirically investigates the impact of managerial entrenchment on firm financial performance of Chinese firms initial public offerings （IPOs）. Using 142 firms listed in the Shenzhen Stock Exchange （SZSE）, which was collected from the Guotaian Research Service Center （GTA-RSC） databases, this study uses two proxies to measure firm performance and three proxies to measure managerial entrenchment. The two proxies for firm performance are Tobins＇ Q and return on assets （ROA）, and the three proxies for managerial entrenchment are entrenchment 1, entrenchment 2, and entrenchment 3. These three entrenchment proxies are derived from the principal component analysis （PCA）. Though previous studies of managerial entrenchment and firm performance variables suffer from endogeneity, with respect to the corporate governance it is unclear as to which variables are endogenous and which are exogenous. This study confirms that the data are linear and no endogeneity issue should be address in this study, but only heteroskedasticity, non-normality for Tobins＇ Q are a problem, therefore, the regression method employed for Tobins＇ Q is the generalised least square （GLS） and the ordinary least square （OLS） between estimators for ROA. The regression result for Tobins＇ Q reveals that managerial entrenchment is negatively impact on firm performance. The results are in contradiction to the stewardship theory for new firms whereas the managerial entrenchment for new firms is positive. Furthermore, only one entrenchment proxy yields a significant coefficient. In conclusion, the negative results of entrenchment proxies were caused by the different institutional structures and legal systems which are the Chinese corporations that are still largely owned and controlled by a state and hence the centralised state controlled was responsible for all managerial actions.
文摘In recent years, managers＇ self-interest motivation has been attracting more and more attention from both the academia and practice.Therefore, the ways and depth of managers＇ self-interest motivation influencing listed companies＇ operating performance has become a hot research area with important theoretical and practical significance. Based on the samples of A-share companies listed in Shanghai and Shenzhen stock exchange during 2012-2014. we studied different effects of managers＇ self-interest motivation on listed company＇s business performance under different situations.The innovation of this paper mainly lies in the following two points： on the one hand, we did not adopt the previous research methods which does not distinguish different kinds of company＇s business performance. Therefore, we divided business performance into two types firstly, then we made empirical text of the influences of managers＇ self-interest motivation on business performance by virtue of Hausman Model and drew related conclusions under different situations of operating performance. On the other hand, the index measuring managers＇ self-interest is relatively new.
基金This paper was Supported by Chinese Humanities and Social Science Foundation for Youths by Ministry of Education, Mechanism and Institutional arrangements on China＇s low-cost model to achieve economic growth cycle （No. 09YJC630228）, and Basic Research Funds of Zhongnan University of Economics and Law ＂Research on Integrated Controlling of Cost Soot among Organization： Based on Synerzistic Effects of Precession＂.
文摘Logistics industry has become the driving force of economic growth. However, the logistics industry develops very slowly because the institutional factors have critically hindered the whole development of logistics industry in China. Institutional factors are regarded as the important factor for logistics cost under the market segmentation of peasant mentality. By comparison of the institutional costs in United States, Japan, India and the Europe, deep reason of high cost behind cost driving force is analyzed. Countermeasure is put forward, such as reducing the prices of domestic toll road, using fuel tax as implemented for highway construction funds, and decreasing the restricted policy for carrying freight cars etc..
文摘Four urban greenbelt types including roadside greenbelt, resident-area greenbelt, landscape forest, and forest park, were simultaneously investigated in Shenzhen, China, in such measures as air temperature, air humidity, wind speed, air anion ratio, and inhalabal particle concentration, which were strongly related with pleasing feeling of human body. The results show that the average air temperature in both forest park and landscape forest is much closer to the pleasing feeling of human body temperature than that of the rest two greenbelts, where it is 1.782 ℃ and 0.837℃ in forest park as well as 3.084 ℃ and 2.140 ℃ in landscape forest less than that of roadside and resident-area greenbelts, respectively. In terms of mean air humidity, forest park and landscape forest are 3.034% and 7.563% higher than that of roadside greenbelt, and 1.205% and 5.734% higher than that of resident-area greenbelt, respectively, implying a sound humidity feeling of human comfort in the former two types. The air cleanness holds a descending rank as forest park, landscape forest, resident-area greenbelt, and roadside greenbelt, whereas the rank in inhalable particle concentration is completely reverse. In general, landscape forest and forest park that mainly consist of trees have a comparatively higher feeling of human comfort whereas roadside and resident-area greenbelts fluctuate irregularly to some extent for the measures studied. The four greenbelt types investigated could be summarized in human comfort as the following descending rank, forest park, landscape forest, resident-area greenbelt, and roadside greenbelt.
