多聚焦图像融合的最佳小波分解层数

多聚焦图像融合的最佳小波分解层数的确定是图像融合研究中的一个热点,本文提出了一种确定多聚焦图像融合的最佳小波分解层数的方法。本文采用四种经典的图像相似性度量指标计算不同小波分解层的低频子带信号的相似度,根据相似性度量的计算结果来确定最佳的小波分解层数。然后比较不同分解层的融合后的图像与原始图像,来验证最佳小波分解层数的选择的合理性。实验结果表明了该方法是可行的、有效的。

基于Kinect的声源定位时延获取及算法性能研究

声源定位已广泛地应用于视频会议和语音控制系统中,针对传统的声源定位系统中采集电路采集到的声音信号易受噪音和混响的影响,提出采用运动传感输入设备Kinect中集成的小型线性麦克风阵列采集音频信号,通过Kinect采集四通道音频信号,并应用互相关(CC)、相位变换(PHAT)、最大似然估计(ML)和平均平方差函数(ASDF)等四种时延算法对采集的音频信号进行处理分析,从而获取时延实现声源的定位。另外,从信号-噪音比(SNR)、峰值锐化两个方面分别利用MATLAB仿真和实测实验比较了四种算法的性能。实验结果表明,利用Kinect线性麦克风阵列采集定位能更有效地去除噪声,提高信噪比,并且四种算法中相位变换法拥有尖锐的峰值和较低的信噪比门限,从而能够适用于声源定位中获取精确时延。

基于语音停顿度和平坦度的注意缺陷与多动障碍自动检测算法

针对注意缺陷与多动障碍(ADHD)临床诊断主要依靠医生主观评估,缺乏客观辅助依据的问题,提出了一种基于语音停顿度和平坦度的ADHD自动检测算法。首先,通过频带差能熵积(FDEEP)参数自动定位语音有话区间,并提取停顿度特征;然后,使用变换平均幅度平方差(TAASD)参数计算语音倍频率,并提取平坦度特征;最后,结合融合特征和支持向量机(SVM)分类器来实现ADHD的自动识别。实验共采集了17位正常对照组儿童和37位ADHD患儿的语音样本。实验结果表明,所提算法能自动检测正常儿童和ADHD患儿,识别正确率为91.38%。

Simulation Model for Photosynthetic Production in Oilseed Rape

Photosynthetic production is a major determinant of final yield in crop plants. A simulation model was developed for canopy photosynthesis and dry matter accumulation in oilseed rape (Brassica napus L.) based on the ecophysiological processes and using a three-layer radiation balance scheme for calculating the radiation interception and absorption by the layers of flowers, pods, and leaves within the canopy. Gaussian integration method was used to calculate photosynthesis of the pod and leaf layers, and the daily total canopy photosynthesis was determined by the sum of photosynthesis from the two layers of green organs. The effects of physiological age, temperature, nitrogen, and water deficit on maximum photosynthetic rate were quantified. Maintenance and growth respiration were estimated to determine net photosynthetic production. Partition index of the shoot in relation to physiological development time was used to calculate shoot dry matter from plant biomass and shoot biomass loss because of freezing was quantified by temperature effectiveness. Testing of the model for dynamic dry matter accumulation through field experiments of different genotypes, sowing dates, and nitrogen levels showed good fit between the observed and simulated data, with an average root mean square error of 10.9% for shoot dry matter. Thus, the present model appears to be reliable for the prediction of photosynthetic production in oilseed rape.

Artificial neural network approach for rheological characteristics of coal-water slurry using microwave pre-treatment

Detailed experimental investigations were carried out for microwave pre-treatment of high ash Indian coal at high power level(900 W) in microwave oven. The microwave exposure times were fixed at60 s and 120 s. A rheology characteristic for microwave pre-treatment of coal-water slurry(CWS) was performed in an online Bohlin viscometer. The non-Newtonian character of the slurry follows the rheological model of Ostwald de Waele. The values of n and k vary from 0.31 to 0.64 and 0.19 to 0.81 Pa·sn,respectively. This paper presents an artificial neural network(ANN) model to predict the effects of operational parameters on apparent viscosity of CWS. A 4-2-1 topology with Levenberg-Marquardt training algorithm(trainlm) was selected as the controlled ANN. Mean squared error(MSE) of 0.002 and coefficient of multiple determinations(R^2) of 0.99 were obtained for the outperforming model. The promising values of correlation coefficient further confirm the robustness and satisfactory performance of the proposed ANN model.

Semi-Blind Pilot-Aided Channel Estimation in Uplink Cloud Radio Access Networks

In this paper, a quasi-Newton method fbr semi-blind estimation is derived for channel estimation in uplink cloud radio access networks （C-RANs）. Different from traditional pilot-aided estimation, semiblind estimation utilizes the unknown data symbols in addition to the known pilot symbols to estimate the channel. An initial channel state information （CSI） obtained by least-squared （LS） estimation is needed in semi-blind estimation. BFGS （Brayben, Fletcher, Goldfarb and Shanno） algorithm, which employs data as well as pilot symbols, estimates the CSI though solving the problem provided by maximum-likelihood （ML） principle. In addition, mean-square-error （MSE） used to evaluate the estimation performance can be further minimized with an optimal pilot design. Simulation results show that the semi-blind estimation achieves a significant improvement in terms of MSE performance over the conventional LS estimation by utilizing data symbols instead of increasing the number of pilot symbols, which demonstrates the estimation accuracy and spectral efficiency are both improved by semiblind estimation for C-RANs.

Online model identification of lithium-ion battery for electric vehicles

In order to characterize the voltage behavior of a lithium-ion battery for on-board electric vehicle battery management and control applications,a battery model with a moderate complexity was established.The battery open circuit voltage (OCV) as a function of state of charge (SOC) was depicted by the Nernst equation.An equivalent circuit network was adopted to describe the polarization effect of the lithium-ion battery.A linear identifiable formulation of the battery model was derived by discretizing the frequent-domain description of the battery model.The recursive least square algorithm with forgetting was applied to implement the on-line parameter calibration.The validation results show that the on-line calibrated model can accurately predict the dynamic voltage behavior of the lithium-ion battery.The maximum and mean relative errors are 1.666% and 0.01%,respectively,in a hybrid pulse test,while 1.933% and 0.062%,respectively,in a transient power test.The on-line parameter calibration method thereby can ensure that the model possesses an acceptable robustness to varied battery loading profiles.

Refining Soil Organic Matter Determination by Loss-on-Ignition

Wet oxidation procedure,i.e.,Walkley-Black (WB) method,is a routine,relatively accurate,and popular method for the determination of soil organic matter (SOM) but it is time-consuming,costly and also has a high potential to cause environmental pollution because of disposal of chromium and strong acids used in this analysis.Therefore,loss-on-ignition (LOI) procedure,a simple and cheap method for SOM estimation,which also avoids chromic acid wastes,deserves more attention.The aims of this research were to study the statistical relationships between SOM determined with the LOI (SOMLOI) and WB (SOMWB) methods to compare the spatial variability of SOM in two major plains,Shahrekord and Koohrang plains,of Chaharmahal-va-Bakhtiari Province,Iran.Fifty surface soil samples (0-25 cm) were randomly collected in each plain to determine SOM using the WB method and the LOI procedure at 300,360,400,500 and 550 ℃ for 2 h.The samples covered wide ranges of soil texture and calcium carbonate equivalent (CCE).The general linear form of the regression equation was calculated to estimate SOM LOI from SOM obtained by the WB method for both overall samples and individual plains.Forty soil samples were also randomly selected to compare the SOM and CCE before and after ignition at each temperature.Overall accuracy of the continuous maps generated for the LOI and WB methods was considered to determine the accordance of two procedures.Results showed a significant positive linear relationship between SOM LOI and SOM WB.Coefficients of determination (R2) of the equations for individual plains were higher than that of the overall equation.Coefficients of determination and line slopes decreased and root mean square error (RMSE) increased with increasing ignition temperature,which may be due to the mineral structural water loss and destruction of carbonates at higher temperatures.A temperature around 360 ℃ was identified as optimum as it burnt most organic carbon,destroyed less inorganic carbon,caused less clay structural water loss,and used less electrical energy.Although the trends of SOM in the kriged maps by the two procedures accorded well,low overall accuracy was observed for the maps obtained by the two methods.While not suitable for determination where high accuracy is required,determination of organic carbon through LOI is likely suitable for exploratory soil surveys where rough estimation of organic matter is required.