基于时间序列分解的江苏省猪肉价格波动分析

以2002年1月～2012年3月江苏省的生猪、仔猪、猪肉市场月度价格为研究对象,采用X12季节调整法和H-P滤波法对猪肉价格的波动进行分解实证分析。研究发现,三者的价格波动呈高度一致的周期性波动上升,短期内波动受外部影响明显,波动幅度较大;价格波动周期与生猪饲养周期相一致,大约39个月为一个周期。     

副热带高压对“灿鸿”和“苏迪罗”台风路径的影响

本文利用美国国家环境预报中心(NCEP)6 h一次的全球分析资料及其10 d低通滤波资料对"灿鸿"和"苏迪罗"台风期间的环流场进行分析。结果表明,副高减弱和加强是台风路径北折和维持西行的原因,且在滤波场上该作用更加明显,对台风业务预报更有帮助。     

Harmonic Damage of Power Usage in Civil Building and Relevant Restraining Method

This paper introduces some common harmonic damage of power usage in civil building and analyzes some reasons for it. Then, some practical and simple restraining methods are suggested and some calculating methods are given as reference for electric engineering technicians.     

Noise-reduction of Digital Video Image Based on Time-recursive Filtering

With the analysis of the principle of time-recursive filter, the authors find that the nature of time-recursive filter is Weighted Mean Low-Pass filter and the relationship between filter coefficients and SNR and the artifact arising from the area where motion can not be tracked. One approach based on Automatic Control Method is proposed to solve the artifacts problem during the process of filtering and the authors designed the corresponding hardware based on FPGA and software respectively. The experimental results show that the time-recursive filtering is good at digital video image denoising and reduces the random noise of digital camera system.     

A Multi-Species Investigation of Sponges’ Filtering Activity towards Marine Microalgae

Chronic discharge of surplus organic matter is a typical side effect of fish aquaculture, occasionally leading to coastal eutrophication and excessive phytoplankton growth. Owing to their innate filter-feeding capacity, marine sponges could mitigate environmental impact under integrated multitrophic aquaculture (IMTA) scenarios. Herein, we investigated the clearance capacity of four ubiquitous Mediterranean sponges (Agelas oroides, Axinella cannabina, Chondrosia reniformis and Sarcotragus foetidus) against three microalgal substrates with different size/motility characteristics: the nanophytoplankton Nannochloropsis sp. (~3.2 μm, nonmotile) and Isochrysis sp. (~3.8 μm, motile), as well as the diatom Phaeodactylum tricornutum (~21.7 μm, nonmotile). In vitro cleaning experiments were conducted using sponge explants in 1 L of natural seawater and applying different microalgal cell concentrations under light/dark conditions. The investigated sponges exhibited a wide range of retention efficiencies for the different phytoplankton cells, with the lowest average values found for A. cannabina (37%) and the highest for A. oroides (70%). The latter could filter up to 14.1 mL seawater per hour and gram of sponge wet weight, by retaining 100% of Isochrysis at a density of 10⁵ cells mL⁻¹, under darkness. Our results highlight differences in filtering capacity among sponge species and preferences for microalgal substrates with distinct size and motility traits.     

我国羊肉市场价格波动研究

本文利用季节调整法和H-P滤波法分析了2002年至2013年我国羊肉市场价格波动周期及产生的原因,并提出稳定羊肉价格的对策和建议。     

Research on Anti-noise Processing Method of Production Signal Based on Ensemble Empirical Mode Decomposition(EEMD)

The grain production prediction is one of the most important links in precision agriculture. In the process of grain production prediction, mechanical noise caused by the factors of difference in field topography and mechanical vibration will be mixed in the original signal, which undoubtedly will affect the prediction accuracy. Therefore, in order to reduce the influence of vibration noise on the prediction accuracy, an adaptive Ensemble Empirical Mode Decomposition (EEMD) threshold filtering algorithm was applied to the original signal in this paper: the output signal was decomposed into a finite number of Intrinsic Mode Functions (IMF) from high frequency to low frequency by using the Empirical Mode Decomposition (EMD) algorithm which could effectively restrain the mode mixing phenomenon; then the demarcation point of high and low frequency IMF components were determined by Continuous Mean Square Error criterion (CMSE), the high frequency IMF components were denoised by wavelet threshold algorithm, and finally the signal was reconstructed. The algorithm was an improved algorithm based on the commonly used wavelet threshold. The two algorithms were used to denoise the original production signal respectively, the adaptive EEMD threshold filtering algorithm had significant advantages in three denoising performance indexes of signal denoising ratio, root mean square error and smoothness. The five field verification tests showed that the average error of field experiment was 1.994% and the maximum relative error was less than 3%. According to the test results, the relative error of the predicted yield per hectare was 2.97%, which was relative to the actual yield. The test results showed that the algorithm could effectively resist noise and improve the accuracy of prediction.     

生物慢滤技术的应用与发展

随着慢滤技术的改进与发展，预处理技术如粗滤、预臭氧处理等使得慢滤可适合处理不同的水源水，而且可去除更多的污染物。在慢滤池中加入一层活性炭可以提高其去除人工合成有机物的能力。介绍了传统慢滤池和改进型慢滤池的一些设计参数，讨论了最近几年来研究人员对慢滤技术所做的改进以及慢滤技术的应用。     

自动基流分割法在北洛河流域的适宜性对比

基流是枯水季节河川径流的重要补给来源,河川基流量及其变化对流域生态健康和水资源合理利用具有重要作用。确定适宜流域生态环境特点的基流分割法,在基流研究中是十分关键的工作。以北洛河流域上游典型黄土丘陵沟壑区刘家河站的多年实测径流资料为基础,分析BFI,HYSEP、数字滤波等三类共9种基流分割法的适宜性,结果表明:BFI法和HYSEP法分割结果比较接近,所得基流指数在0.399 4~0.428 1。尤其修正BFI法估算的基流量及过程线,能够客观反映研究流域流量过程线退水段的物理规律。综合考虑变异性、稳定性、过程线吻合程度等方面,认为修正BFI法是黄土区水文研究中进行基流分割的适宜方法。