A data-aided technique for cartier frequency offset estimation with continuous phase modulation (CPM) in burst- mode transmission is presented. The proposed technique first exploits a special pilot sequence, or trai...A data-aided technique for cartier frequency offset estimation with continuous phase modulation (CPM) in burst- mode transmission is presented. The proposed technique first exploits a special pilot sequence, or training sequence, to form a sinusoidal waveform. Then, an improved dichotomous search frequency offset estimator is introduced to determine the frequency offset using the sinusoid. Theoretical analysis and simulation results indicate that our estimator is noteworthy in the following aspects. First, the estimator can operate independently of timing recovery. Second, it has relatively low outlier, i.e., the minimum signal-to-noise ratio (SNR) required to guarantee estimation accuracy. Finally, the most important property is that our estimator is complexity-reduced compared to the existing dichotomous search methods: it eliminates the need for fast Fourier transform (FFT) and modulation removal, and exhibits faster convergence rate without accuracy degradation.展开更多
In this paper,the problem of 3-D steady heat conduction including the influenceof phase change on billets is turned into the 2-D transient problem by a suitable transformation technique. The effective specific heat ha...In this paper,the problem of 3-D steady heat conduction including the influenceof phase change on billets is turned into the 2-D transient problem by a suitable transformation technique. The effective specific heat has been employed to substitutefor the effect of the phase ceange.The computational formulation of finite element has been presented. And the careful disposal of the phase change region has also beengiven.展开更多
To solve the difficulty of designing digital impacting filter in the receiver of random-polar modulated Extended Binary Phase Shift Keying with Continuous Phase (CP-EBPSK), a design method based on Quantum-behaved Par...To solve the difficulty of designing digital impacting filter in the receiver of random-polar modulated Extended Binary Phase Shift Keying with Continuous Phase (CP-EBPSK), a design method based on Quantum-behaved Particle Swarm Optimization (QPSO) algorithm is proposed. Firstly, QPSO is introduced elaborately, and the basic flow of QPSO is also given. Then, the demodulation principle of digital impacting filter in the communication system of CP-EBPSK with random-polar is demonstrated, and QPSO is utilized to design the digital impacting filter, which also takes the effect of finite word length into consideration when implemented by hardware. Finally, the proposed method is simulated. Simulation results show that the digital impacting filter designed by new method can derive satisfied demodulation performance.展开更多
In this paper, serially concatenated continuous phase modulation (SCCPM) system is analyzed and a reduced state soft input soft output (SlSO) a posteriori probability algorithm is proposed. Based on the reduced st...In this paper, serially concatenated continuous phase modulation (SCCPM) system is analyzed and a reduced state soft input soft output (SlSO) a posteriori probability algorithm is proposed. Based on the reduced state sequence detection (RSSD), it has the more general form compared with other reduced state SISO algorithms. The proposed algorithm can greatly reduce the state number, thus leads to the computation complexity reduction. It also minimizes the degradation in Euclidean distance with decision feedback in the reduced state trellis. Analysis and simulation results show that the performance degradation is little with proper reduction scheme.展开更多
In order to fabricate a large-aperture continuous phase plate(CPP) using atmospheric pressure plasma processing(APPP) with high efficiency and precision, the position dwell mode and velocity mode were proposed and...In order to fabricate a large-aperture continuous phase plate(CPP) using atmospheric pressure plasma processing(APPP) with high efficiency and precision, the position dwell mode and velocity mode were proposed and the iterative calculation method was developed for the non-constant removal rate. Two 320 mm × 320 mm × 2 mm CPPs were fabricated with two processing modes. The experiment results show that the velocity mode is capable of significantly reducing the processing time and shape error. The total processing time is decreased from 13.2 h to 9.3 h, and the surface shape error is decreased from 0.158λ to 0.119λ(λ = 632.8 nm)(root mean square).展开更多
This paper concerns the reconstruction of a dynamic system based on phase space continuation of monthly meantemperature iD time series and the assumption that the equation for the time-varying evolution of phase space...This paper concerns the reconstruction of a dynamic system based on phase space continuation of monthly meantemperature iD time series and the assumption that the equation for the time-varying evolution of phase space statevariables contains linear and nonlinear quadratic terms. followed by the fitting of the dataset subjected to continuation so as to get, by the least square method. the coefficients of the terms, of which those of greater variance contribution are retained for use. Results show that the obtained low-order system may be used to describe nonlinear properties of the short range climate variation shown by monthly mean temperature series.展开更多
This paper investigates the nonlinear prediction of monthly rainfall time series which consists of phase space continuation of one-dimensional sequence, followed by least-square determination of the coefficients for t...This paper investigates the nonlinear prediction of monthly rainfall time series which consists of phase space continuation of one-dimensional sequence, followed by least-square determination of the coefficients for the terms ofthe time-lag differential equation model and then fitting of the prognostic expression is made to 1951-1980 monthlyrainfall datasets from Changsha station. Results show that the model is likely to describe the nonlinearity of the allnual cycle of precipitation on a monthly basis and to provide a basis for flood prevention and drought combating forthe wet season.展开更多
<b>Background: </b>Tuberculosis (TB) caused by <i>Mycobacterium tuberculosis </i>is one of the top 10 causes of death worldwide. Despite the global impact of TB and treatment received, a gap pe...<b>Background: </b>Tuberculosis (TB) caused by <i>Mycobacterium tuberculosis </i>is one of the top 10 causes of death worldwide. Despite the global impact of TB and treatment received, a gap persists between treatment and quality of life of the patients especially in resource limited countries. This study therefore evaluated the health related quality of life of TB patients and the different factors influencing their quality of life at the post intensive phase of their treatment in the Fako division of the South-West Region of Cameroon. <b>Methods: </b>A hospital based cross sectional study was carried out in 4 tuberculosis treatment centers, namely two regional (Buea and Limbe) and two district (Tiko and Muyuka) hospitals in Fako Division between June and July 2017. One hundred and sixty-seven TB patients were enrolled in the study and relevant information from them was gathered using the SF-36 questionnaire. Various aspects such as their perception of the disease, their socio-demographics and socio-economics conditions were evaluated. <b>Results: </b>Of the 167 participants enrolled in the study, 95 (56.9%) were male and 72 (43.1%) were female. One hundred and thirty-three (79.6%) of the 167 participants were affected by pulmonary tuberculosis and 34 (20.4%) by extra-pulmonary tuberculosis. Fifty-five (32.9%) were HIV positive and 90 (53.9%) had been receiving treatment for 4 - 6 months, 73 (43.7%) for 1 - 3 months and 4 (2.4%) for 7 - 9 months. The lowest and highest scores were recorded on the role limitation due to emotional problems scale (30.54 ± 35.36), and on the social functioning scale (47.68 ± 16.33) respectively. There was a significant difference (p = 0.021), between pulmonary and extra pulmonary tuberculosis (49.15 ± 16.08 vs. 41.91 ± 16.25) on the social functioning. Financial difficulty restraining drug collection affected the general health perception (p = 0.003), vitality (p = 0.007), emotional well-being (p < 0.001) and social functioning (p = 0.05) of the patients. Low income affected the vitality (p = 0.039), emotional well-being (p = 0.015), role limitations due to physical (p = 0.046) and emotional (p = 0.003) problems of the patients. Equally, the HIV status affected their vitality (p < 0.001) and emotional well-being (p = 0.011). <b>Conclusion:</b> The quality of life of the TB patients in the study area was generally poor. Counselling of diagnosed TB patients and provision of financial assistance through a social package can improve the acceptance of the disease during their treatment period to avoid default and relapse.展开更多
The Q-ary low-density parity-check(LDPC) coded high order partial response continuous phase modulation(PR-CPM) with double iterative loops is investigated. This scheme shows significant improvements in power and b...The Q-ary low-density parity-check(LDPC) coded high order partial response continuous phase modulation(PR-CPM) with double iterative loops is investigated. This scheme shows significant improvements in power and bandwidth efficiency, but at the expense of long iterative decoding delay and computational complexity induced by the improper match between the demodulator and the decoder. To address this issue, the convergence behavior of Q-ary LDPC coded CPM is investigated for the Q=2 and Q〉2 cases, and an optimized design method based on the extrinsic information transfer chart is proposed to improve the systematic iterative efficiency. Simulation results demonstrate that the proposed method can achieve a perfect tradeoff between iterative decoding delay and bit error rate performance to satisfy real-time applications.展开更多
The continuous phase modulation(CPM)technique is widely used in range telemetry due to its high spectral efficiency and power efficiency.However,the demodulation performance of the traditional maximum likelihood seque...The continuous phase modulation(CPM)technique is widely used in range telemetry due to its high spectral efficiency and power efficiency.However,the demodulation performance of the traditional maximum likelihood sequence detection(MLSD)algorithm significantly deteriorates in non-ideal synchronization or fading channels.To address this issue,this work proposes a convolutional neural network(CNN)called the cascade parallel crossing network(CPCNet)to enhance the robustness of CPM signals demodulation.The CPCNet model employs a multiple parallel structure and feature fusion to extract richer features from CPM signals.This approach constructs feature maps at different levels,resulting in a more comprehensive training of the model and improved demodulation performance.Simulation results show that under Gaussian channel,the proposed CPCNet achieves the same bit error rate(BER)performance as MLSD method when there is no timing error,but with 1/4 symbol period timing error,the proposed method has 2 dB demodulation gain compared with CNN and convolutional long short-term memory deep neural network(CLDNN).In addition,under Rayleigh channel,the BER of the proposed method is reduced by 5%-87%compared to that of MLSD in the wide signal-to-noise ratio(SNR)region.展开更多
For the EOF decomposition continuation phase space, the least square method is applied under the condition of orthogonal basis to find coefficients of all quadratic nonlinear terms of a state evo- lution equation such...For the EOF decomposition continuation phase space, the least square method is applied under the condition of orthogonal basis to find coefficients of all quadratic nonlinear terms of a state evo- lution equation such that a dynamic system that indicates the evolution features of a weather/cli- mate system in a limited area can be formulated. The scheme is compared with that for phase space continuation by time series drift. Results show that the dynamic system established in terms of the present method is likely to give more precise and realistic description of evolution of the weather/ climate system.展开更多
In order to solve the problem of high computational complexity in demodulation for multi-h continuous phase modulation(CPM) signal, a maximum cumulative measure combing with the Laurent decomposition(MCM-LD) scheme is...In order to solve the problem of high computational complexity in demodulation for multi-h continuous phase modulation(CPM) signal, a maximum cumulative measure combing with the Laurent decomposition(MCM-LD) scheme is proposed to reduce the number of the grid states and the required number of matched filters, which degrades the demodulation complexity at the receiver.The advanced range telemetry(ARTM) Tier Ⅱ CPM signal is adopted to evaluate the performance in simulation. The results show that, compared with the traditional maximum likelihood sequence detection(MLSD), MCM-LD can respectively reduce the numbers of grid states and matched filters from 256 to 32 and 128 to 48 with negligible performance loss, which effectively degrades the computational complexity for multi-h CPM signal.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.61301179)the Doctorial Programs Foundation of the Ministry of Education,China(Grant No.20110203110011)the Programme of Introducing Talents of Discipline to Universities,China(Grant No.B08038)
文摘A data-aided technique for cartier frequency offset estimation with continuous phase modulation (CPM) in burst- mode transmission is presented. The proposed technique first exploits a special pilot sequence, or training sequence, to form a sinusoidal waveform. Then, an improved dichotomous search frequency offset estimator is introduced to determine the frequency offset using the sinusoid. Theoretical analysis and simulation results indicate that our estimator is noteworthy in the following aspects. First, the estimator can operate independently of timing recovery. Second, it has relatively low outlier, i.e., the minimum signal-to-noise ratio (SNR) required to guarantee estimation accuracy. Finally, the most important property is that our estimator is complexity-reduced compared to the existing dichotomous search methods: it eliminates the need for fast Fourier transform (FFT) and modulation removal, and exhibits faster convergence rate without accuracy degradation.
文摘In this paper,the problem of 3-D steady heat conduction including the influenceof phase change on billets is turned into the 2-D transient problem by a suitable transformation technique. The effective specific heat has been employed to substitutefor the effect of the phase ceange.The computational formulation of finite element has been presented. And the careful disposal of the phase change region has also beengiven.
基金Supported by the National Natural Science Foundation of China (No. 60872075)
文摘To solve the difficulty of designing digital impacting filter in the receiver of random-polar modulated Extended Binary Phase Shift Keying with Continuous Phase (CP-EBPSK), a design method based on Quantum-behaved Particle Swarm Optimization (QPSO) algorithm is proposed. Firstly, QPSO is introduced elaborately, and the basic flow of QPSO is also given. Then, the demodulation principle of digital impacting filter in the communication system of CP-EBPSK with random-polar is demonstrated, and QPSO is utilized to design the digital impacting filter, which also takes the effect of finite word length into consideration when implemented by hardware. Finally, the proposed method is simulated. Simulation results show that the digital impacting filter designed by new method can derive satisfied demodulation performance.
基金the National Natural Science Foundation of China (Grant Nos. 60496316, 60532060 and 60572146)the Research Fund for the Doctoral Program of Higher Education (Grant No. 20050701007)China Teaching and Research Award Program for Outstanding Young Teachers in Higher Education Institutions of MOE, MOE Key Project (Grant No. 107103)
文摘In this paper, serially concatenated continuous phase modulation (SCCPM) system is analyzed and a reduced state soft input soft output (SlSO) a posteriori probability algorithm is proposed. Based on the reduced state sequence detection (RSSD), it has the more general form compared with other reduced state SISO algorithms. The proposed algorithm can greatly reduce the state number, thus leads to the computation complexity reduction. It also minimizes the degradation in Euclidean distance with decision feedback in the reduced state trellis. Analysis and simulation results show that the performance degradation is little with proper reduction scheme.
基金supported by the National Natural Science Foundation of China(No.51175123)the National Science and Technology Major Project(No.2013ZX04006011-205)
文摘In order to fabricate a large-aperture continuous phase plate(CPP) using atmospheric pressure plasma processing(APPP) with high efficiency and precision, the position dwell mode and velocity mode were proposed and the iterative calculation method was developed for the non-constant removal rate. Two 320 mm × 320 mm × 2 mm CPPs were fabricated with two processing modes. The experiment results show that the velocity mode is capable of significantly reducing the processing time and shape error. The total processing time is decreased from 13.2 h to 9.3 h, and the surface shape error is decreased from 0.158λ to 0.119λ(λ = 632.8 nm)(root mean square).
文摘This paper concerns the reconstruction of a dynamic system based on phase space continuation of monthly meantemperature iD time series and the assumption that the equation for the time-varying evolution of phase space statevariables contains linear and nonlinear quadratic terms. followed by the fitting of the dataset subjected to continuation so as to get, by the least square method. the coefficients of the terms, of which those of greater variance contribution are retained for use. Results show that the obtained low-order system may be used to describe nonlinear properties of the short range climate variation shown by monthly mean temperature series.
文摘This paper investigates the nonlinear prediction of monthly rainfall time series which consists of phase space continuation of one-dimensional sequence, followed by least-square determination of the coefficients for the terms ofthe time-lag differential equation model and then fitting of the prognostic expression is made to 1951-1980 monthlyrainfall datasets from Changsha station. Results show that the model is likely to describe the nonlinearity of the allnual cycle of precipitation on a monthly basis and to provide a basis for flood prevention and drought combating forthe wet season.
文摘<b>Background: </b>Tuberculosis (TB) caused by <i>Mycobacterium tuberculosis </i>is one of the top 10 causes of death worldwide. Despite the global impact of TB and treatment received, a gap persists between treatment and quality of life of the patients especially in resource limited countries. This study therefore evaluated the health related quality of life of TB patients and the different factors influencing their quality of life at the post intensive phase of their treatment in the Fako division of the South-West Region of Cameroon. <b>Methods: </b>A hospital based cross sectional study was carried out in 4 tuberculosis treatment centers, namely two regional (Buea and Limbe) and two district (Tiko and Muyuka) hospitals in Fako Division between June and July 2017. One hundred and sixty-seven TB patients were enrolled in the study and relevant information from them was gathered using the SF-36 questionnaire. Various aspects such as their perception of the disease, their socio-demographics and socio-economics conditions were evaluated. <b>Results: </b>Of the 167 participants enrolled in the study, 95 (56.9%) were male and 72 (43.1%) were female. One hundred and thirty-three (79.6%) of the 167 participants were affected by pulmonary tuberculosis and 34 (20.4%) by extra-pulmonary tuberculosis. Fifty-five (32.9%) were HIV positive and 90 (53.9%) had been receiving treatment for 4 - 6 months, 73 (43.7%) for 1 - 3 months and 4 (2.4%) for 7 - 9 months. The lowest and highest scores were recorded on the role limitation due to emotional problems scale (30.54 ± 35.36), and on the social functioning scale (47.68 ± 16.33) respectively. There was a significant difference (p = 0.021), between pulmonary and extra pulmonary tuberculosis (49.15 ± 16.08 vs. 41.91 ± 16.25) on the social functioning. Financial difficulty restraining drug collection affected the general health perception (p = 0.003), vitality (p = 0.007), emotional well-being (p < 0.001) and social functioning (p = 0.05) of the patients. Low income affected the vitality (p = 0.039), emotional well-being (p = 0.015), role limitations due to physical (p = 0.046) and emotional (p = 0.003) problems of the patients. Equally, the HIV status affected their vitality (p < 0.001) and emotional well-being (p = 0.011). <b>Conclusion:</b> The quality of life of the TB patients in the study area was generally poor. Counselling of diagnosed TB patients and provision of financial assistance through a social package can improve the acceptance of the disease during their treatment period to avoid default and relapse.
基金supported by the National Natural Science Foundation of China(61403093)the Science Foundation of Heilongjiang Province of China for Returned Scholars(LC2013C22)the Assisted Project by Heilongjiang Province of China Postdoctoral Funds for Scientific Research Initiation(LBH-Q14048)
文摘The Q-ary low-density parity-check(LDPC) coded high order partial response continuous phase modulation(PR-CPM) with double iterative loops is investigated. This scheme shows significant improvements in power and bandwidth efficiency, but at the expense of long iterative decoding delay and computational complexity induced by the improper match between the demodulator and the decoder. To address this issue, the convergence behavior of Q-ary LDPC coded CPM is investigated for the Q=2 and Q〉2 cases, and an optimized design method based on the extrinsic information transfer chart is proposed to improve the systematic iterative efficiency. Simulation results demonstrate that the proposed method can achieve a perfect tradeoff between iterative decoding delay and bit error rate performance to satisfy real-time applications.
基金Supported by the Beijing Natural Science Foundation (L202003)。
文摘The continuous phase modulation(CPM)technique is widely used in range telemetry due to its high spectral efficiency and power efficiency.However,the demodulation performance of the traditional maximum likelihood sequence detection(MLSD)algorithm significantly deteriorates in non-ideal synchronization or fading channels.To address this issue,this work proposes a convolutional neural network(CNN)called the cascade parallel crossing network(CPCNet)to enhance the robustness of CPM signals demodulation.The CPCNet model employs a multiple parallel structure and feature fusion to extract richer features from CPM signals.This approach constructs feature maps at different levels,resulting in a more comprehensive training of the model and improved demodulation performance.Simulation results show that under Gaussian channel,the proposed CPCNet achieves the same bit error rate(BER)performance as MLSD method when there is no timing error,but with 1/4 symbol period timing error,the proposed method has 2 dB demodulation gain compared with CNN and convolutional long short-term memory deep neural network(CLDNN).In addition,under Rayleigh channel,the BER of the proposed method is reduced by 5%-87%compared to that of MLSD in the wide signal-to-noise ratio(SNR)region.
基金This work is sponsored by the National Natural Science Foundation of Chinathe Natural Science Foundation of Jiangsu Province
文摘For the EOF decomposition continuation phase space, the least square method is applied under the condition of orthogonal basis to find coefficients of all quadratic nonlinear terms of a state evo- lution equation such that a dynamic system that indicates the evolution features of a weather/cli- mate system in a limited area can be formulated. The scheme is compared with that for phase space continuation by time series drift. Results show that the dynamic system established in terms of the present method is likely to give more precise and realistic description of evolution of the weather/ climate system.
文摘In order to solve the problem of high computational complexity in demodulation for multi-h continuous phase modulation(CPM) signal, a maximum cumulative measure combing with the Laurent decomposition(MCM-LD) scheme is proposed to reduce the number of the grid states and the required number of matched filters, which degrades the demodulation complexity at the receiver.The advanced range telemetry(ARTM) Tier Ⅱ CPM signal is adopted to evaluate the performance in simulation. The results show that, compared with the traditional maximum likelihood sequence detection(MLSD), MCM-LD can respectively reduce the numbers of grid states and matched filters from 256 to 32 and 128 to 48 with negligible performance loss, which effectively degrades the computational complexity for multi-h CPM signal.