In terms of the electromagnetic wave measurement while drilling,the extremely low frequency electromagnetic(ELF-EM)signal below 20Hz is usually chosen as the downhole data carrier.To improve the transmission rate of E...In terms of the electromagnetic wave measurement while drilling,the extremely low frequency electromagnetic(ELF-EM)signal below 20Hz is usually chosen as the downhole data carrier.To improve the transmission rate of ELF-EM signal and the signal to noise ratio(SNR)at the receiving end,the DQPSK modulation was proposed as the modulation method for the communication of electromagnetic wave system.Different from the traditional IQ orthogonal modulation and coherent demodulation methods,the proposed phase selection modulation and correlation algorithm demodulation are easier to implement and more practical.With regard to the communication synchronization,a fast algorithm,which based on the normalized cross-relation number,was used for waveform matching,and the maximum point of the correlation coefficient was used as the starting point of communication synchronization.The communication simulation results show that the proposed DQPSK modulation signal based on the adaptive combined filtering algorithm has better terminal error rate and transmission rate than the traditional modulation method.Under the same carrier frequency and code width,the transmission rate of DQPSK modulation is 4 to 5 times and 2 times that of PPM modulation and 2DPSK modulation respectively.The communication modulation and demodulation modes as well as the decoding algorithm with combined adaptive filter proposed in this paper can effectively solve practical engineering problems.展开更多
A new method called joint Matched Filter (MF) combining and turbo equalization is proposed for wireless communications over Inter-Symbol Interference (ISI) channels with diversity reception. This method takes diversit...A new method called joint Matched Filter (MF) combining and turbo equalization is proposed for wireless communications over Inter-Symbol Interference (ISI) channels with diversity reception. This method takes diversity combining and equalization as integrity and need just one turbo equalizer for all diversity branches. Computer simulations prove that our method can take advantage of turbo equalization and diversity reception to combat fading of wireless channels.展开更多
Based on the fact that recycling of combined filter backwash water(CFBW)directly to drinking water treatment plants(WTP)is considered to be a feasible method to enhance pollutant removal efficiency,we were motivat...Based on the fact that recycling of combined filter backwash water(CFBW)directly to drinking water treatment plants(WTP)is considered to be a feasible method to enhance pollutant removal efficiency,we were motivated to evaluate the genotoxicity of water samples from two pilot-scale drinking water treatment systems,one with recycling of combined backwash water,the other one with a conventional process.An integrated approach of the comet and micronucleus(MN)assays was used with zebrafish(Danio rerio)to investigate the water genotoxicity in this study.The total organic carbon(TOC),dissolved organic carbon(DOC),and trihalomethane formation potential(THMFP),of the recycling process were lower than that of the conventional process.All the results showed that there was no statistically significant difference(P〉0.05)between the conventional and recycling processes,and indicated that the genotoxicity of water samples from the recycling process did not accumulate in 15 day continuous recycling trial.It was worth noting that there was correlation between the concentrations of TOC,DOC,UV(254),and THMFPs in water and the DNA damage score,with corresponding R^2 values of 0.68,0.63,0.28,and 0.64.Nevertheless,both DNA strand breaks and MN frequency of all water samples after disinfection were higher than that of water samples from the two treatment units,which meant that the disinfection by-products(DBPs)formed by disinfection could increase the DNA damage.Both the comet and MN tests suggest that the recycling process did not increase the genotoxicity risk,compared to the traditional process.展开更多
Content-based image retrieval has been an active area of research for more than ten years. Gabor schemes and support vector machine (SVM) method have been proven effective in image representation and clas-sification...Content-based image retrieval has been an active area of research for more than ten years. Gabor schemes and support vector machine (SVM) method have been proven effective in image representation and clas-sification. In this paper, we propose a retrieval scheme based on Gabor filters and SVMs for hepatic computed tomography (CT) images query. In our experiments, a batch of hepatic CT images containing several types of CT findings are used for the retrieval test. Precision comparison between our scheme and existing methods is presented.展开更多
This paper presents an image denoising method based on bilateral filtering and non-local means. The non-local region texture or structure of the image has the characteristics of repetition, which can be used to effect...This paper presents an image denoising method based on bilateral filtering and non-local means. The non-local region texture or structure of the image has the characteristics of repetition, which can be used to effectively preserve the edge and detail of the image. And compared with classical methods, bilateral filtering method has a better performance in denosing for the reason that the weight includes the geometric closeness factor and the intensity similarity factor. We combine the geometric closeness factor with the weight of non-local means, and construct a new weight. Experimental results show that the modified algorithm can achieve better performance. And it can protect the image detail and structure information better.展开更多
基金supported by National Natural Science Foundation of China(No.61771366)Stable-Support Scientific Project of China Research Institute of Radiowave Propagation(Grant No.A132201068 and No.A132107W08)。
文摘In terms of the electromagnetic wave measurement while drilling,the extremely low frequency electromagnetic(ELF-EM)signal below 20Hz is usually chosen as the downhole data carrier.To improve the transmission rate of ELF-EM signal and the signal to noise ratio(SNR)at the receiving end,the DQPSK modulation was proposed as the modulation method for the communication of electromagnetic wave system.Different from the traditional IQ orthogonal modulation and coherent demodulation methods,the proposed phase selection modulation and correlation algorithm demodulation are easier to implement and more practical.With regard to the communication synchronization,a fast algorithm,which based on the normalized cross-relation number,was used for waveform matching,and the maximum point of the correlation coefficient was used as the starting point of communication synchronization.The communication simulation results show that the proposed DQPSK modulation signal based on the adaptive combined filtering algorithm has better terminal error rate and transmission rate than the traditional modulation method.Under the same carrier frequency and code width,the transmission rate of DQPSK modulation is 4 to 5 times and 2 times that of PPM modulation and 2DPSK modulation respectively.The communication modulation and demodulation modes as well as the decoding algorithm with combined adaptive filter proposed in this paper can effectively solve practical engineering problems.
基金Supported by the National Natural Science Foundation of China (No. 60572176)
文摘A new method called joint Matched Filter (MF) combining and turbo equalization is proposed for wireless communications over Inter-Symbol Interference (ISI) channels with diversity reception. This method takes diversity combining and equalization as integrity and need just one turbo equalizer for all diversity branches. Computer simulations prove that our method can take advantage of turbo equalization and diversity reception to combat fading of wireless channels.
基金supported by the Major Science and Technology Program for Water Pollution Control and Treatment(Nos.2012ZX07408001,2014ZX07405002)the National Natural Science Foundation of China(No.51108118)the State Key Laboratory of Urban Water Resource and Environment(No.2013DX12)
文摘Based on the fact that recycling of combined filter backwash water(CFBW)directly to drinking water treatment plants(WTP)is considered to be a feasible method to enhance pollutant removal efficiency,we were motivated to evaluate the genotoxicity of water samples from two pilot-scale drinking water treatment systems,one with recycling of combined backwash water,the other one with a conventional process.An integrated approach of the comet and micronucleus(MN)assays was used with zebrafish(Danio rerio)to investigate the water genotoxicity in this study.The total organic carbon(TOC),dissolved organic carbon(DOC),and trihalomethane formation potential(THMFP),of the recycling process were lower than that of the conventional process.All the results showed that there was no statistically significant difference(P〉0.05)between the conventional and recycling processes,and indicated that the genotoxicity of water samples from the recycling process did not accumulate in 15 day continuous recycling trial.It was worth noting that there was correlation between the concentrations of TOC,DOC,UV(254),and THMFPs in water and the DNA damage score,with corresponding R^2 values of 0.68,0.63,0.28,and 0.64.Nevertheless,both DNA strand breaks and MN frequency of all water samples after disinfection were higher than that of water samples from the two treatment units,which meant that the disinfection by-products(DBPs)formed by disinfection could increase the DNA damage.Both the comet and MN tests suggest that the recycling process did not increase the genotoxicity risk,compared to the traditional process.
基金the Joint National Natural Science Foundation of China under Grant No.30770589.
文摘Content-based image retrieval has been an active area of research for more than ten years. Gabor schemes and support vector machine (SVM) method have been proven effective in image representation and clas-sification. In this paper, we propose a retrieval scheme based on Gabor filters and SVMs for hepatic computed tomography (CT) images query. In our experiments, a batch of hepatic CT images containing several types of CT findings are used for the retrieval test. Precision comparison between our scheme and existing methods is presented.
基金supported by the Student’s Platform for Innovation and Entrepreneurship Training Program(No.201510060022)
文摘This paper presents an image denoising method based on bilateral filtering and non-local means. The non-local region texture or structure of the image has the characteristics of repetition, which can be used to effectively preserve the edge and detail of the image. And compared with classical methods, bilateral filtering method has a better performance in denosing for the reason that the weight includes the geometric closeness factor and the intensity similarity factor. We combine the geometric closeness factor with the weight of non-local means, and construct a new weight. Experimental results show that the modified algorithm can achieve better performance. And it can protect the image detail and structure information better.