改进的基于频率顺序的小波包消噪方法

针对传统小波包消噪方法消噪效果不佳、精度不高的问题,提出了一种以小波包频率顺序为基础,结合小波包分解系数能量谱和新阈值函数的消噪方法.利用小波包分解系数能量谱实现了低频段和高频段的小波包分解系数的细化处理.通过插值得到的新阈值函数,不仅克服了传统软、硬阈值函数的缺点,实现了阈值的平滑过渡,还可以在软、硬阈值函数间进行灵活的转换.仿真结果表明,与传统小波包消噪方法相比,新方法有效提高了消噪精度,保留了信号在各个频段的细节信息,减少了信号的失真,具有更好的消噪效果.

真性红细胞增多症中医辨治规律系统综述

[目的]分析真性红细胞增多症病因、病机、辨证分型、证候要素及用药规律。[方法]系统综述方法,关键词:中医、中医药、中西医结合、真性红细胞增多症、骨髓增殖性疾病,检索中国知网(CNKI)、万方数据库(Wanfang Data)、维普中文科技期刊数据库(VIP)1980年1月—2016年9月RCT文献,同时追溯纳入文献参考文献,建立数据库,统计分析证型、证素、中药使用。[结果]初筛文献153篇,逐层筛选,最终纳入文献95篇,获取101个证候类型,规范为69个证候类型。纯实证类证型43个,虚实夹杂类证型23个,纯虚类证型3个。证型频率顺序:气滞血瘀、肝热血瘀、血瘀证、气虚血瘀、肝胆实火。病位证素频率顺序:肝、肾、胆、血分、经络、营分;病性证素类中病因证素频率顺序:热(火)、湿、毒(疫疠)。实证证素频率顺序血瘀、气滞、血热。虚证证素频率顺序:阴虚、气虚、血虚。用药:共使用18大类199味药,前5位种类频率顺序:清热、活血化瘀、补虚、解表、平肝息风。前8位药物频率顺序:生地、赤芍、当归、红花、桃仁、甘草、丹参、柴胡。[结论]合理使用清热解毒药-提高疗效关键,活血化瘀-贯穿治疗始终,重视理气药使用。

Enhancing manual P-phase arrival detection and automatic onset time picking in a noisy microseismic data in underground mines

Accurate detection and picking of the P-phase onset time in noisy microseismic data from underground mines remains a big challenge. Reliable P-phase onset time picking is necessary for accurate source location needed for planning and rescue operations in the event of failures. In this paper, a new technique based on the discrete stationary wavelet transform （DSWT）and higher order statist!cs, is proposed for processing noisy data from underground mines. The objectives of this method are to （1） Improve manual detection and tPicking of P-phase onset; and （ii） provide an automatic means of detecting and picking P-phase onset me accurately. The DSWT is first used to filter the signal over several scales. The manual P-phase onset detection and picking are then obtained by computing the signal energy across selected scales with frequency bands that capture the signal of interest. The automatic P-phase onset, on the other hand, is achieved by using skewness- and kurtosis-based criterion applied to selected scales in a time-frequency domain. The method was tested using synthetic and field data from an underground limestone mine. Results were compared with results obtained by using the short-term to long-term average （STA/LTA） ratio and that by Reference Ge et al. （2009）. The results show that the me!hod provides a more reliable estimate of the P-phase onset arrival than the STA]LTA method when the signal to noise ratio is very low. Also, the results obtained from the field data matched accurately with the results from Reference Ge et al. （2009）.

小波包多阈值去噪法及其在形变分析中的应用

在形变分析中,传统的小波去噪只保留低频上的有用信息,很容易去掉中频以及高频上的有用信息。小波包分析方法则同时考虑了各个频段上的有用信息,因此是一种更为精细的去噪方法,小波包去噪的关键是对小波包分解系数选取合适的阈值准则并进行阈值处理,但传统的小波包去噪并没有对此进行充分的研究。针对传统小波、小波包分析的不足,本文提出一种基于频率顺序并依据信息类型分段的多阈值准则小波包去噪法。通过理论分析与实际应用,结果表明该方法能够高效剔除各频段的噪声,同时当采样频率较低时能有效保留去噪信号中频率较高的有用信息,其去噪能力优于传统的小波、小波包等其他去噪方法,因此可以广泛应用于高精度变形监测领域中。

A Four-Element Sensor Array Consisting of Asymmetric Distributed-Feedback Fiber Lasers

A sensor array system formed by arranging four asymmetric distributed-feedback fiber lasers （DFB-FL） in ascending order according to their slope efficiencies was proposed. The output flatness could be effectively improved with the application of asymmetric DFB-FLs. The last element had almost the same output with the others although it obtained the smallest pump power. The relative intensity noise （RIN） and relaxation oscillation frequency of the sensor array were also analyzed. It is found that the relaxation oscillation frequency of a certain DFB-FL was relevant to its relative position in the array. And the RIN of a certain DFB-FL was always affected by the other elements in the array, which was not dependent on the order of their arrangement.