Equalization for continuous phase modulation over frequency-selective fading channels

This paper presents an equalization algorithm for continuous phase modulation （CPM） over frequency-selective channels. A specific training sequence is first embedded in each data packet. By recursive least-squares （RLS） estimation, the channel information parameters can be acquired, and a fractionally Simulation results show that the proposed algorithm can acquire the spaced equalizer performs joint decoding and equalization. channel information parameters rapidly and accurately, and that the fractionally spaced equalizer can eliminate the intersymbol interference （ISI） effectively, and is not sensitive to timing inaccuracy, so this algorithm can be exploited for demodulation system in burst mode.

SERIALLY CONCATENATED CONTINUOUS PHASE MODULATION WITH REDUCED ITERATIVE DEMODULATION AND DETECTION

A reduced state Soft Input Soft Output (SISO) a posteriori probability algorithm for Seri-ally Concatenated Continuous Phase Modulation (SCCPM) is proposed in this paper. Based on the Reduced State Sequence Detection (RSSD),it has 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 perform-ance degradation is little with proper reduction scheme.

Improved dichotomous search frequency offset estimator for burst-mode continuous phase modulation

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.

Effect of Continuous Phase Viscosity on Membrane Emulsification

Oil-in-water(o/w) emulsions were produced with a membrane emulsification system. The effect of the continuous phase viscosity on the emulsification was studied. The theoretical analyses show that the continuous phase viscosity influences not only the flow field of the continuous phase but also the interfacial tension. The droplet size distribution and disperse phase flux for different continuous phase viscosity were investigated experimentally at constant wall shear stress and constant volume flow rate of the continuous phase respectively.

A reduced state SISO iterative decoding algorithm for serially concatenated continuous phase modulation

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.

THE TEMPERATURE ANALYSIS OF THE BILLET WITH PHASE CHANGE DURING CONTINUOUS CASTING

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.

液相连续法生产丙烯酸乙酯的合成工艺研究

近些年,丙烯酸乙酯相关产业多采用气相固定床法,该方法存在能耗较高、设备投资大、生产切换不方便、丙烯酸单程转化率低和生产成本高等一系列问题。因此,本文研究了一种液相连续法生产丙烯酸乙酯的合成工艺路线以解决上述问题。以丙烯酸和95%乙醇为原料,采用液相连续法合成丙烯酸乙酯,其结构经^(1)H NMR,^(13)C NMR和HR-MS(EI)确证。研究了反应温度、停留时间、 95%(质量分数)乙醇用量、催化剂用量(质量分数)和萃取剂用量对于液相连续法生产丙烯酸乙酯的影响。结果表明:在丙烯酸与95%乙醇物质的量之比为1.0∶2.0,第一级反应釜反应温度为75℃、第二级反应釜反应温度为80℃、第三级反应釜反应温度为90℃、反应停留时间为4 h、催化剂物质的量分数为0.4%(催化剂相对于丙烯酸原料的物质的量分数)和萃取液和萃取剂质量比为1.0∶2.0的条件下丙烯酸乙酯单程收率达到95.0%,经工业级放大后丙烯酸乙酯单程收率达到95.3%。上述研究在一定程度上解决了气相固定床方法的一系列缺陷,为丙烯酸乙酯的工业生产提供了一种较为优异的生产方式。

Research on numerical emulator of mine methane and coal dust explosion

The mathematical physics model of mine methane and coal dust explosion propagation was established in the research,by using continuous phase,combustion,par- ticulate equations of mathematical physics.Based upon the data from mine methane drainage roadway explosion,and mine methane and coal dust explosion propagation ex- perimental studies,the numerical emulator system of mine methane and coal dust explo- sion software was developed by using prevalent flow simulation platform,which can be used to simulate the explosion accidents process effectively.In addition,the system can also be used to determine whether coal dust involved in the explosion,and to simulate accurately the transition from deflagration to detonation in methane explosion,propagation velocity of explosion shock,attenuation pattern,and affected area of explosion.

DESIGN OF DIGITAL IMPACTING FILTER IN CP-EBPSK WITH RANDOM-POLAR COMMUNICATION SYSTEM

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.

SYMMETRIC INFORMATION RATE OF CPM AND OPTIMAL DETECTOR DESIGN

This paper first calculates numerically the Symmetric Information Rate (SIR) of Cotinuous Phase Modulation (CPM) schemes over Additive White Gaussian Noise (AWGN) channel, modeling CPM and channel as a Memory-less Modulator (MM) plus a Markov Finite State Channel (FSMC), then proposes an optimal detector, which is of BCJR based Decision Feedback Detector (DFD) but non-iterative. It can achieve the SIR as the sequence length approaches infinity while the complexity is extremely low. Finally, both theoretic proof and numerical simulation are performed to show the op- timality. Simulation results show that it nearly achieves the theoretic bound and outperforms the Viterbi Detector (VD) with 2dB in low Eb/N0.

Improved iterative convergence method in Q-ary LDPC coded high order PR-CPM

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.

Effect of Ca addition on microstructure and impression creep behavior of cast AZ61 magnesium alloy

Microstructure and creep properties of AZ61 alloy containing 1 and 3 wt.% Ca were investigated. The creep properties were examined using impression method under different stresses between 200 and 500 MPa at the temperature ranging from 423 to 491 K. The microstructure of AZ61 alloy contains α(Mg) matrix and Mg17 Al12 intermetallic phases. It is shown that adding Ca to AZ61 alloy reduces the amount of Mg17 Al12 phase via forming(Mg,Al)2 Ca phase;furthermore, increasing the Ca content to 3 wt.% leads to the formation of(Mg,Al)2 Ca phase, as well as the elimination of the Mg17 Al12 phase. Creep properties of AZ61 alloy are improved with the Ca addition. The improvement in creep properties is attributed to the reduction in the amount of Mg17 Al12 phase and the formation of(Mg,Al)2 Ca phase with high thermal stability. According to the obtained creep data, it is concluded that the pipe diffusion-climb controlled dislocation creep is the dominant creep mechanism and Ca addition has no influence on this mechanism. The effect of pre-deformation on the creep properties of AZ61+3%Ca alloy reveals that the creep resistance of the alloy depends on the continuity of(Mg,Al)2 Ca phase. It is decreased by reducing the phase continuity.

Assessment of Health-Related Quality of Life of Tuberculosis Patients in Fako Division, South-West Region of Cameroon

Background: Tuberculosis (TB) caused by Mycobacterium tuberculosis 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. Methods: 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. Results: 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). Conclusion: 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.

Preliminary Study of Reconstruction of a Dynamic System Using an One－Dimensional Time Series

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.

A Nonlinear Time-lag Differential Equation Mdel for Predicting Monthly Precipitation

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.

CNN demodulation model with cascade parallel crossing for CPM signals

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.

A STUDY OF DYNAMIC SYSTEM ESTABLISHMENT IN EOF-CONTINUATION PHASE SPACE

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.

Maximum-likelihood Block Detection for CPM Signals

This paper deals with noncoherent Maximum-likelihood Block Detection (MLBD) of uncodedCPM signals (full response CPM and parrtal response CPM) over an additive white noise (AWGN)channel. Based on the work of W. Osborne and M. Simon ,this paper generalizes Maximum-likelihoodBlork Detection. Then we focus on the error performance of MLBD, which is named one-symbol MLBDand N-symbol MLBD respectively. By computer simulation of CPFSK, 1RC and 2RC , it is found thatMLBD can improve the error performance over traditional noncoherent detection.

Low-complexity detection based on maximum cumulative measure and Laurent decomposition for multi-h CPM signal

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.