Nanofiltration (NF) membrane can efficiently remove the ions from groundwater, especially for high valence ions. Results show that the removal rate of fluoride was approximately 67% by the NF system, while for arsenic...Nanofiltration (NF) membrane can efficiently remove the ions from groundwater, especially for high valence ions. Results show that the removal rate of fluoride was approximately 67% by the NF system, while for arsenic the removal rate was more than 93%. NF presented the well selective removal for fluoride. The quality of product water meets the national drinking water standards. Therefore, the application of nanofiltration technology can significantly improve the drinking water environment of rural areas, avoiding the secondary pollution caused by other chemical treatment processes. The water product cost of NF technology is about RMB 0.026 yuan per liter, application of the process of 2:1 NF membranes arrangement for toxic or harmful ions removal from groundwater, including investment cost and operating cost. Therefore, NF technology for harmful ions removal is more economical than the price of the market bottled water and suitable for application in rural areas of China.展开更多
Communication opportunities among vehicles are important for data transmission over the Internet of Vehicles(IoV).Mixture models are appropriate to describe complex spatial-temporal data.By calculating the expectation...Communication opportunities among vehicles are important for data transmission over the Internet of Vehicles(IoV).Mixture models are appropriate to describe complex spatial-temporal data.By calculating the expectation of hidden variables in vehicle communication,Expectation Maximization(EM)algorithm solves the maximum likelihood estimation of parameters,and then obtains the mixture model of vehicle communication opportunities.However,the EM algorithm requires multiple iterations and each iteration needs to process all the data.Thus its computational complexity is high.A parameter estimation algorithm with low computational complexity based on Bin Count(BC)and Differential Evolution(DE)(PEBCDE)is proposed.It overcomes the disadvantages of the EM algorithm in solving mixture models for big data.In order to reduce the computational complexity of the mixture models in the IoV,massive data are divided into relatively few time intervals and then counted.According to these few counted values,the parameters of the mixture model are obtained by using DE algorithm.Through modeling and analysis of simulation data and instance data,the PEBCDE algorithm is verified and discussed from two aspects,i.e.,accuracy and efficiency.The numerical solution of the probability distribution parameters is obtained,which further provides a more detailed statistical model for the distribution of the opportunity interval of the IoV.展开更多
文摘Nanofiltration (NF) membrane can efficiently remove the ions from groundwater, especially for high valence ions. Results show that the removal rate of fluoride was approximately 67% by the NF system, while for arsenic the removal rate was more than 93%. NF presented the well selective removal for fluoride. The quality of product water meets the national drinking water standards. Therefore, the application of nanofiltration technology can significantly improve the drinking water environment of rural areas, avoiding the secondary pollution caused by other chemical treatment processes. The water product cost of NF technology is about RMB 0.026 yuan per liter, application of the process of 2:1 NF membranes arrangement for toxic or harmful ions removal from groundwater, including investment cost and operating cost. Therefore, NF technology for harmful ions removal is more economical than the price of the market bottled water and suitable for application in rural areas of China.
基金This work was supported by the Fundamental Research Funds for the Central Universities(Grant No.FRF-BD-20-11A)the Scientific and Technological Innovation Foundation of Shunde Graduate School,USTB(Grant No.BK19AF005).
文摘Communication opportunities among vehicles are important for data transmission over the Internet of Vehicles(IoV).Mixture models are appropriate to describe complex spatial-temporal data.By calculating the expectation of hidden variables in vehicle communication,Expectation Maximization(EM)algorithm solves the maximum likelihood estimation of parameters,and then obtains the mixture model of vehicle communication opportunities.However,the EM algorithm requires multiple iterations and each iteration needs to process all the data.Thus its computational complexity is high.A parameter estimation algorithm with low computational complexity based on Bin Count(BC)and Differential Evolution(DE)(PEBCDE)is proposed.It overcomes the disadvantages of the EM algorithm in solving mixture models for big data.In order to reduce the computational complexity of the mixture models in the IoV,massive data are divided into relatively few time intervals and then counted.According to these few counted values,the parameters of the mixture model are obtained by using DE algorithm.Through modeling and analysis of simulation data and instance data,the PEBCDE algorithm is verified and discussed from two aspects,i.e.,accuracy and efficiency.The numerical solution of the probability distribution parameters is obtained,which further provides a more detailed statistical model for the distribution of the opportunity interval of the IoV.
