Beneficiation of non-coking coal is gaining ground in India. It not only reduces the volume of inert content to be transported to the power plant and also lowers the wear in the boiler houses. For special applications...Beneficiation of non-coking coal is gaining ground in India. It not only reduces the volume of inert content to be transported to the power plant and also lowers the wear in the boiler houses. For special applications such as the fuel for integrated gasification combined cycle plant （IGCC）, the ash content in the coal should preferably be below 15 %. Indian coals are characterized by high inter-grown ash content mainly due to ＇drift origin＇ of Gondwana formation in Permian age. This warrants fine grinding of non-coking coal in order to liberate the ash forming minerals from coal macerals. A non- coking coal sample of vitrinite type from India was ground to 44 ~tm （dso） and subjected to column flotation to improve its quality. The non-coking coal analyzing 34.6 % ash, 26.2 % volatile matter, 1.3 % moisture and 37.9 % fixed carbon could be upgraded to a concentrate/froth of 14.83 % ash at 72.18 % yield by optimizing collector and frother dosages and flotation column operating parameters, namely, froth depth, superficial feed velocity and superficial air velocity. The concentrate produced by this process is suitable as fuel for IGCC in coal-to-electricity route.展开更多
Background： Preventing anterior cruciate ligament（ACL） injuries is very important for athletes, and dynamic knee valgus is considered a risk factor for non-contact ACL injury. However, little is known about whether...Background： Preventing anterior cruciate ligament（ACL） injuries is very important for athletes, and dynamic knee valgus is considered a risk factor for non-contact ACL injury. However, little is known about whether the functions of the hip abductor and rear-foot increase dynamic knee valgus. A two-dimensional（2D） video-based screening test focused on hip abductor and rear-foot functions among factors involved in dynamic knee valgus. The present study determined associations between hip and rear-foot dynamic alignment and dynamic knee valgus.Methods： This cross-sectional study recruited 130 female basketball players（258 legs） from nine high-school teams. The players performed single-leg squats and single-leg drop landings to provide knee-in（KID） and hip-out（HOD） distances on 2D video images. Hip and rear-foot dynamic alignment was evaluated using a dynamic Trendelenburg test（DTT） and a dynamic heel-floor test（HFT）.Results： The Chi-square test revealed no significant difference in the prevalence of DTT-positivity between single-leg squats（28.7%） and singleleg drop landings（23.3%）. The prevalence of HFT-positivity was significantly greater during landings（51.4%） than during single-leg squats（31.0%, p 〈 0.01）. The KID values for both single-leg squats and single-leg drop landings were greater in the DTT-positive than in the DTTnegative group（15.1 5.4 cm and 20.2 7.5 cm, p 〈 0.001）. The HOD values were similarly greater in the DTT-positive group（15.2 1.9 cm and 17.6 2.8 cm, p 〈 0.001）. The KID values for both single-leg squats and single-leg drop landings were greater in the HFT-positive than in the HFT-negative group（12.2 5.1 cm, p 〈 0.01; 14.7 7.2 cm, p 〈 0.001）, whereas HOD values for these tasks did not significantly differ between the two groups.Conclusion： Dynamic hip mal-alignment might be associated with both greater KID and HOD, whereas rear-foot eversion is associated only with greater KID. Hip abductor and rear-foot dysfunction are important factors for dynamic knee valgus and thus evaluating DTT and HFT will help to prevent dynamic knee valgus.展开更多
In this paper,we propose a discrepancy rule-based method to automatically choose the regularization parameters for total variation image restoration problems. The regularization parameters are adjusted dynamically in ...In this paper,we propose a discrepancy rule-based method to automatically choose the regularization parameters for total variation image restoration problems. The regularization parameters are adjusted dynamically in each iteration.Numerical results are shown to illustrate the performance of the proposed method.展开更多
During the reform era, Chinese cities witnessed dramatic institutional transformation and spatial restructuring in general and profound change of commuting patterns in particular. Using household surveys collected in ...During the reform era, Chinese cities witnessed dramatic institutional transformation and spatial restructuring in general and profound change of commuting patterns in particular. Using household surveys collected in Guangzhou, China, in 2001, 2005 and 2010, excess commuting measurements are estimated. Excess commuting shows an overall trend of increasing during 1990–1999, and then declining during 2000–2010. We argue that deepening marketization of the jobs and housing sectors has induced spatial separation of jobs and housing. In other words, institutional transition and urban spatial restructuring are underpinning the changes of commuting patterns in Chinese cities. Excess commuting has strong relationship with individual socio-demographic status, which is by and large due to the increasing flexibilities of jobs and housing location choices enjoyed by urban residents. The findings call for considerations on balancing jobs-housing in making public policies relevant to urban development in general, and land use and transportation in particular.展开更多
This paper concerns with modeling and design of an algorithm for the portfolio selection problems with fixed transaction costs and minimum transaction lots. A mean-variance model for the portfolio selection problem is...This paper concerns with modeling and design of an algorithm for the portfolio selection problems with fixed transaction costs and minimum transaction lots. A mean-variance model for the portfolio selection problem is proposed, and the model is formulated as a non-smooth and nonlinear integer programming problem with multiple objective functions. As it has been proven that finding a feasible solution to the problem only is already NP-hard, based on NSGA-II and genetic algorithm for numerical optimization of constrained problems (Genocop), a multi-objective genetic algorithm (MOGA) is designed to solve the model. Its features comprise integer encoding and corresponding operators, and special treatment of constraints conditions. It is illustrated via a numerical example that the genetic algorithm can efficiently solve portfolio selection models proposed in this paper. This approach offers promise for the portfolio problems in practice.展开更多
In this paper, a tractable solution is proposed to integrate, to a certain extent, market liquidity risk in the portfolio selection process. It is shown how an investor may take advantage of this additional risk sourc...In this paper, a tractable solution is proposed to integrate, to a certain extent, market liquidity risk in the portfolio selection process. It is shown how an investor may take advantage of this additional risk source within the standard mean-variance optimization framework, by in certain circumstances overcoming the pitfalls of illiquidity and in others seizing a liquidity premium. Bid prices appear effective to capture liquidity risk. The efficient frontier conceived with bid prices consists of mean-variance optimal allocations that cover more liquid stocks （large caps） under stressed market conditions and less liquid stocks （small caps） under normal conditions.展开更多
Mixed integer linear programming （MILP） approach for simultaneous gross error detection and data reconciliation has been proved as an efficient way to adjust process data with material, energy, and other balance con...Mixed integer linear programming （MILP） approach for simultaneous gross error detection and data reconciliation has been proved as an efficient way to adjust process data with material, energy, and other balance constrains. But the efficiency will decrease significantly when this method is applled in a large-scale problem because there are too many binary variables involved. In this article, an improved method is proposed in order to gen- erate gross error candidates with reliability factors before data rectification. Candidates are used in the MILP objec- tive function to improve the efficiency and accuracy by reducing the number of binary variables and giving accurate weights for suspected gross errors candidates. Performance of this improved method is compared and discussed by applying the algorithm in a widely used industrial example.展开更多
This paper critically reviews Hossein Nassaji's Language Learning article, which systematically overviews the recent language processing theories, it is especially pertinent to schema theory as well as Walter Kint...This paper critically reviews Hossein Nassaji's Language Learning article, which systematically overviews the recent language processing theories, it is especially pertinent to schema theory as well as Walter Kintsch's construction-integration (CI) theory in reading comprehension. The article thoroughly investigates the unified theory (as Kintsch defines), construction-integration theory in text comprehension, which is mainly based upon the comparison with and analysis of the applications of schema theory from the perspective of language reading comprehension. The author tries to work out and illustrate this model as an alternative approach to the schema-oriented models previously used to solve reading comprehension problems in language teaching and leaning.展开更多
This paper employs the SCAD-penalized least squares method to simultaneously select variables and estimate the coefficients for high-dimensional covariate adjusted linear regression models.The distorted variables are ...This paper employs the SCAD-penalized least squares method to simultaneously select variables and estimate the coefficients for high-dimensional covariate adjusted linear regression models.The distorted variables are assumed to be contaminated with a multiplicative factor that is determined by the value of an unknown function of an observable covariate.The authors show that under some appropriate conditions,the SCAD-penalized least squares estimator has the so called "oracle property".In addition,the authors also suggest a BIC criterion to select the tuning parameter,and show that BIC criterion is able to identify the true model consistently for the covariate adjusted linear regression models.Simulation studies and a real data are used to illustrate the efficiency of the proposed estimation algorithm.展开更多
Regulating the selectivity of catalysts in selective hydrogenation reactions at the atomic level is highly desirable but remains a grand challenge. Here we report a simple and practical strategy to synthesize a monoli...Regulating the selectivity of catalysts in selective hydrogenation reactions at the atomic level is highly desirable but remains a grand challenge. Here we report a simple and practical strategy to synthesize a monolithic single-atom catalyst(SAC) with isolated Pd atoms supported on bulk nitrogen-doped carbon foams(Pd-SAs/CNF). Moreover, we demonstrate that the single-atom Pd sites with unique electronic structure endow Pd-SAs/CNF with an isolated site effect, leading to excellent activity and selectivity in 4-nitrophenylacetylene semi-hydrogenation reaction. In addition, benefiting from the great integrity and excellent mechanical strength, monolithic Pd-SAs/CNF catalyst is easy to separate from the reaction system for conducting the subsequent recycling. The cyclic test demonstrates the excellent reusability and stability of monolithic Pd-SAs/CNF catalyst.The discovery of isolated site effect provides a new approach to design highly selective catalysts. And the development of monolithic SACs provides new opportunities to advance the practical applications of single-atom catalysts.展开更多
In this paper,a prediction model on Chinese annual live hog supply was established.With cointegration test,backward and forward stochastic selection and other methods,four main factors(hog price,prices of inputs in ho...In this paper,a prediction model on Chinese annual live hog supply was established.With cointegration test,backward and forward stochastic selection and other methods,four main factors(hog price,prices of inputs in hog production,the level of hog inventory,as well as emergency and government policy) were chosen from 16 relevant factors to establish the model and make improvement.Applied the improved model,annual live hog supply in China from 2013 to 2016 was predicted in three scenarios.The predicted results showed that if there were no major emergencies from 2013 to 2016,there would be an upward trend in Chinese live hog supply year by year.The supply of live hogs in China in 2013 would be about 707.663 million head,in 2014 would be between 715.935 and 742.969 million head,in 2015 between 734.458 and 779.413 million head,and in 2016 between 750.923 and809.450 million head.展开更多
文摘Beneficiation of non-coking coal is gaining ground in India. It not only reduces the volume of inert content to be transported to the power plant and also lowers the wear in the boiler houses. For special applications such as the fuel for integrated gasification combined cycle plant （IGCC）, the ash content in the coal should preferably be below 15 %. Indian coals are characterized by high inter-grown ash content mainly due to ＇drift origin＇ of Gondwana formation in Permian age. This warrants fine grinding of non-coking coal in order to liberate the ash forming minerals from coal macerals. A non- coking coal sample of vitrinite type from India was ground to 44 ~tm （dso） and subjected to column flotation to improve its quality. The non-coking coal analyzing 34.6 % ash, 26.2 % volatile matter, 1.3 % moisture and 37.9 % fixed carbon could be upgraded to a concentrate/froth of 14.83 % ash at 72.18 % yield by optimizing collector and frother dosages and flotation column operating parameters, namely, froth depth, superficial feed velocity and superficial air velocity. The concentrate produced by this process is suitable as fuel for IGCC in coal-to-electricity route.
文摘Background： Preventing anterior cruciate ligament（ACL） injuries is very important for athletes, and dynamic knee valgus is considered a risk factor for non-contact ACL injury. However, little is known about whether the functions of the hip abductor and rear-foot increase dynamic knee valgus. A two-dimensional（2D） video-based screening test focused on hip abductor and rear-foot functions among factors involved in dynamic knee valgus. The present study determined associations between hip and rear-foot dynamic alignment and dynamic knee valgus.Methods： This cross-sectional study recruited 130 female basketball players（258 legs） from nine high-school teams. The players performed single-leg squats and single-leg drop landings to provide knee-in（KID） and hip-out（HOD） distances on 2D video images. Hip and rear-foot dynamic alignment was evaluated using a dynamic Trendelenburg test（DTT） and a dynamic heel-floor test（HFT）.Results： The Chi-square test revealed no significant difference in the prevalence of DTT-positivity between single-leg squats（28.7%） and singleleg drop landings（23.3%）. The prevalence of HFT-positivity was significantly greater during landings（51.4%） than during single-leg squats（31.0%, p 〈 0.01）. The KID values for both single-leg squats and single-leg drop landings were greater in the DTT-positive than in the DTTnegative group（15.1 5.4 cm and 20.2 7.5 cm, p 〈 0.001）. The HOD values were similarly greater in the DTT-positive group（15.2 1.9 cm and 17.6 2.8 cm, p 〈 0.001）. The KID values for both single-leg squats and single-leg drop landings were greater in the HFT-positive than in the HFT-negative group（12.2 5.1 cm, p 〈 0.01; 14.7 7.2 cm, p 〈 0.001）, whereas HOD values for these tasks did not significantly differ between the two groups.Conclusion： Dynamic hip mal-alignment might be associated with both greater KID and HOD, whereas rear-foot eversion is associated only with greater KID. Hip abductor and rear-foot dysfunction are important factors for dynamic knee valgus and thus evaluating DTT and HFT will help to prevent dynamic knee valgus.
基金supported in part by NSFC Grant No.60702030supported in part by NSFC Grant No.10871075the wavelets and information processing program under a grant from DSTA,Singapore
文摘In this paper,we propose a discrepancy rule-based method to automatically choose the regularization parameters for total variation image restoration problems. The regularization parameters are adjusted dynamically in each iteration.Numerical results are shown to illustrate the performance of the proposed method.
基金Under the auspices of Ministry of Education of Humanities and Social Sciences Project(No.09YJC840016)National Natural Science Foundation of China(No.41001088)National Basic Research Program of China(No.2014CB460614)
文摘During the reform era, Chinese cities witnessed dramatic institutional transformation and spatial restructuring in general and profound change of commuting patterns in particular. Using household surveys collected in Guangzhou, China, in 2001, 2005 and 2010, excess commuting measurements are estimated. Excess commuting shows an overall trend of increasing during 1990–1999, and then declining during 2000–2010. We argue that deepening marketization of the jobs and housing sectors has induced spatial separation of jobs and housing. In other words, institutional transition and urban spatial restructuring are underpinning the changes of commuting patterns in Chinese cities. Excess commuting has strong relationship with individual socio-demographic status, which is by and large due to the increasing flexibilities of jobs and housing location choices enjoyed by urban residents. The findings call for considerations on balancing jobs-housing in making public policies relevant to urban development in general, and land use and transportation in particular.
文摘This paper concerns with modeling and design of an algorithm for the portfolio selection problems with fixed transaction costs and minimum transaction lots. A mean-variance model for the portfolio selection problem is proposed, and the model is formulated as a non-smooth and nonlinear integer programming problem with multiple objective functions. As it has been proven that finding a feasible solution to the problem only is already NP-hard, based on NSGA-II and genetic algorithm for numerical optimization of constrained problems (Genocop), a multi-objective genetic algorithm (MOGA) is designed to solve the model. Its features comprise integer encoding and corresponding operators, and special treatment of constraints conditions. It is illustrated via a numerical example that the genetic algorithm can efficiently solve portfolio selection models proposed in this paper. This approach offers promise for the portfolio problems in practice.
文摘In this paper, a tractable solution is proposed to integrate, to a certain extent, market liquidity risk in the portfolio selection process. It is shown how an investor may take advantage of this additional risk source within the standard mean-variance optimization framework, by in certain circumstances overcoming the pitfalls of illiquidity and in others seizing a liquidity premium. Bid prices appear effective to capture liquidity risk. The efficient frontier conceived with bid prices consists of mean-variance optimal allocations that cover more liquid stocks （large caps） under stressed market conditions and less liquid stocks （small caps） under normal conditions.
基金Supported by the National High Technology Research and Development Program of China (2007AA40702 and 2007AA04Z191)
文摘Mixed integer linear programming （MILP） approach for simultaneous gross error detection and data reconciliation has been proved as an efficient way to adjust process data with material, energy, and other balance constrains. But the efficiency will decrease significantly when this method is applled in a large-scale problem because there are too many binary variables involved. In this article, an improved method is proposed in order to gen- erate gross error candidates with reliability factors before data rectification. Candidates are used in the MILP objec- tive function to improve the efficiency and accuracy by reducing the number of binary variables and giving accurate weights for suspected gross errors candidates. Performance of this improved method is compared and discussed by applying the algorithm in a widely used industrial example.
文摘This paper critically reviews Hossein Nassaji's Language Learning article, which systematically overviews the recent language processing theories, it is especially pertinent to schema theory as well as Walter Kintsch's construction-integration (CI) theory in reading comprehension. The article thoroughly investigates the unified theory (as Kintsch defines), construction-integration theory in text comprehension, which is mainly based upon the comparison with and analysis of the applications of schema theory from the perspective of language reading comprehension. The author tries to work out and illustrate this model as an alternative approach to the schema-oriented models previously used to solve reading comprehension problems in language teaching and leaning.
基金supported by the National Natural Science Foundation of China under Grant Nos.11471029,11101014,61273221 and 11171010the Beijing Natural Science Foundation under Grant Nos.1142002 and 1112001+1 种基金the Science and Technology Project of Beijing Municipal Education Commission under Grant No.KM201410005010the Research Fund for the Doctoral Program of Beijing University of Technology under Grant No.006000543114550
文摘This paper employs the SCAD-penalized least squares method to simultaneously select variables and estimate the coefficients for high-dimensional covariate adjusted linear regression models.The distorted variables are assumed to be contaminated with a multiplicative factor that is determined by the value of an unknown function of an observable covariate.The authors show that under some appropriate conditions,the SCAD-penalized least squares estimator has the so called "oracle property".In addition,the authors also suggest a BIC criterion to select the tuning parameter,and show that BIC criterion is able to identify the true model consistently for the covariate adjusted linear regression models.Simulation studies and a real data are used to illustrate the efficiency of the proposed estimation algorithm.
基金supported by the National Key R&D Program of China (2018YFA0702003)the National Natural Science Foundation of China (21890383,21671117,21871159 and 21901135)+1 种基金the National Postdoctoral Program for Innovative Talents (BX20180160)the China Postdoctoral Science Foundation (2018M640113)。
文摘Regulating the selectivity of catalysts in selective hydrogenation reactions at the atomic level is highly desirable but remains a grand challenge. Here we report a simple and practical strategy to synthesize a monolithic single-atom catalyst(SAC) with isolated Pd atoms supported on bulk nitrogen-doped carbon foams(Pd-SAs/CNF). Moreover, we demonstrate that the single-atom Pd sites with unique electronic structure endow Pd-SAs/CNF with an isolated site effect, leading to excellent activity and selectivity in 4-nitrophenylacetylene semi-hydrogenation reaction. In addition, benefiting from the great integrity and excellent mechanical strength, monolithic Pd-SAs/CNF catalyst is easy to separate from the reaction system for conducting the subsequent recycling. The cyclic test demonstrates the excellent reusability and stability of monolithic Pd-SAs/CNF catalyst.The discovery of isolated site effect provides a new approach to design highly selective catalysts. And the development of monolithic SACs provides new opportunities to advance the practical applications of single-atom catalysts.
基金supported by the National Key Technology R&D Program under Grant No.2009BADA 9BB01-4the National Natural Science Foundation of China under Grant Nos.71173210 and 61273208
文摘In this paper,a prediction model on Chinese annual live hog supply was established.With cointegration test,backward and forward stochastic selection and other methods,four main factors(hog price,prices of inputs in hog production,the level of hog inventory,as well as emergency and government policy) were chosen from 16 relevant factors to establish the model and make improvement.Applied the improved model,annual live hog supply in China from 2013 to 2016 was predicted in three scenarios.The predicted results showed that if there were no major emergencies from 2013 to 2016,there would be an upward trend in Chinese live hog supply year by year.The supply of live hogs in China in 2013 would be about 707.663 million head,in 2014 would be between 715.935 and 742.969 million head,in 2015 between 734.458 and 779.413 million head,and in 2016 between 750.923 and809.450 million head.
