Infrasound Event Classification Fusion Model Based on Multiscale SE-CNN and BiLSTM

The classification of infrasound events has considerable importance in improving the capability to identify the types of natural disasters.The traditional infrasound classification mainly relies on machine learning algorithms after artificial feature extraction.However,guaranteeing the effectiveness of the extracted features is difficult.The current trend focuses on using a convolution neural network to automatically extract features for classification.This method can be used to extract signal spatial features automatically through a convolution kernel;however,infrasound signals contain not only spatial information but also temporal information when used as a time series.These extracted temporal features are also crucial.If only a convolution neural network is used,then the time dependence of the infrasound sequence will be missed.Using long short-term memory networks can compensate for the missing time-series features but induces spatial feature information loss of the infrasound signal.A multiscale squeeze excitation–convolution neural network–bidirectional long short-term memory network infrasound event classification fusion model is proposed in this study to address these problems.This model automatically extracted temporal and spatial features,adaptively selected features,and also realized the fusion of the two types of features.Experimental results showed that the classification accuracy of the model was more than 98%,thus verifying the effectiveness and superiority of the proposed model.

Impairment of the Endothelium and Disorder of Microcirculation in Humans and Animals Exposed to Infrasound due to Irregular Mechano-Transduction

The microcirculation of mammals is an autoregulated and complex synchronised system according to the current demand for nutrients and oxygen. The undisturbed course of vital functions such as of growth, blood pressure regulation, inflammatory sequence and embryogenesis is bound to endothelial integrity. The sensible vasomotion is particularly dependent on it. Mechano-transduction signalling networks play a critical role in vital cellular processes and are the decisive physiological mechanism for an adequate NO-release, main responsible for the autoregulation of vessels. Disturbed endothelial integrity, originating, e.g., from chronic oxidative stress and/or mechanic (oscillatory) stress, leads to disturbance of vasomotion as well as a disequilibrium of redox systems, recognized as main cause for the development of chronic inflammation diseases such as atherosclerosis and corresponding secondary illnesses, possibly cancer. The endothelial cytoskeleton, which corresponds to a viscoelastic “tensegrity model”, offers the possibility for mechano-transduction via its special construction. The rapidly growing knowledge about mechanical forces in cellular sensing and regulation of the last years (that culminated in the Nobel Prize award for the decoding of pressure/vibration sensing ion channels), led us to the following hypothesis: The extern stressor “Noise” produces under certain conditions an oscillatory stress field in the physiologically laminar flow bed of capillaries, which is able to lead to irregular mechano-transductions. Findings provide a strict dependence on frequency in mechano-transduction with determination of thresholds for a 1:1 transmission. The knowledge, recently gained on endothelial mechano-transduction, sheds a new light on the importance of low frequencies. This could indicate the long-sought pathophysiological way in which infrasound can exert a stressor effect at the cellular level. Noise-exposed citizens, who live near infrastructures such as a biogas installation, heat pumps, block-type thermal power stations and bigger industrial wind turbines (IWT’s), show worldwide mainly a symptomatology associated with microcirculatory disorder. Conceivable are also effects on insects or fishes, since the piezo-channels are recognised as conserved structures of all multicellular organism. An experimental design is proposed to demonstrate the direct pathological influence of infrasound of defined strength, frequency, effect/time profile and duration on the sensitive vasomotion.

Characterisation of the Coherent Infrasound Sources Recorded by the Infrasound International Monitoring System Station I48TN in Tunisia (Mines &Quarries)

The I48TN is one of the 60 International Monitoring System (IMS) stations of the Comprehensive nuclear Test Ban Treaty Organization (CTBTO), characterized by its location in the heart of the IMS Infrasound network. The ability of the International Monitoring System (IMS) infrasound network to detect atmospheric nuclear explosions and other signals of interest is strongly dependent on station-specific ambient noise. This ambient noise, includes both incoherent wind noise and real coherent infrasonic waves. Infrasound analysis software detects tens to hundreds of events per day which consume a lot of time for the Infrasound analysts, to define and categorize events where around 90% of the detections are coherent noise. This study analyzed the importance of the synergy between infrasound and seismic data, and provided the infrasound data analyst with the most important local coherent infrasound sources in the region as recorded by the IMS station I48TN, in order to reduce the workload of the analysts and give them a clear view on the coherent noise affecting this station for better discrimination between events of interest like nuclear explosions and coherent sources. DTK_GPMCC and DIVA software were used to perform this study. Geotool software from the International Data Centre (IDC) was used in analysing seismic data from the Tunisian IMS station KEST. The result of this study allowed the characterization of the most important coherent local infrasound sources (Mines and Quarries) which are considered as coherent noise to I48TN station and correct parameters in some reference events in the Reference Event Database source of the International Data Centre.

Damage to Hippocampus of Rats after Being Exposed to Infrasound

Objective The objective was to observe damage of hippocampus in rats after exposure to infrasound, and to assess HSP70 expression in hippocampus. Methods SD rats in the experimental group were exposed to 140 d B（8 Hz） infrasound for 2 h per day for 3 days. The morphology of the hippocampus was examined by transmission electronic microscopic（TEM）. Cell apoptosis was observed by TUNEL staining at 0 h, 24 h, 48 h, and 2 w after exposure. HSP70 expression was detected by immunohistochemistry（IHC） and Western blotting（WB）. Results TEM showed that hippocampus was significantly damaged by exposure, and exhibited recovery 1 week after exposure. The TUNEL data showed that neuronal apoptosis after exposure was significantly higher than in the control rats at 24 h and 48 h, and the apoptotic cells decreased one week after exposure. IHC and WB showed HSP70 expression was significantly higher in the exposed rats, peaked at 24 h. Conclusion Exposure to 140 d B（8 Hz） infrasound for 2 h per day for 3 days appeared to induce damage to the hippocampus of rats, based on changes in ultrastructure and increased cell apoptosis. However, recovery from the damage occurred overtime. HSP70 expression also increased after the exposure and decreased by 48 h.

Relation of the infrasound characteristics and the continuous steel bridge vibration modes generated by the vibration of moving heavy trucks

As heavy trucks pass over highway bridges, bridge vibration occurs and generates infrasound. General trucks in Japan with rear leaf suspension have whole body vibration （suspension spring vibration） frequencies of about 3 Hz. Also, the frequencies of the wheel vibration （tire spring vibration） are about 10-20 Hz. The continuous steel highway bridges with middle span length have vibration modes with the same phase in each span at the frequencies of about 3 Hz and also have those with the secondary mode shape at the frequencies of about 10-20 Hz. Truck vibrations and bridge vibrations are closely related. In this work, vibration tests are conducted using a heavy test truck for two cases of infrasound complaints in order to investigate the relation between the continuous steel bridge vibration modes generated by the vibration of moving heavy trucks and its infrasound characteristics. As a result of the examination, two types of bridge vibration modes are caused by the vibrations of a moving heavy truck. Moreover, the bending vi- bration modes with the same phase in each span have the most powerful infrasound pressure, since each span vibrates with the same phase. Two countermeasures, including viscoelastic damper at the end of the girders and extended deck method, are proposed to reduce the amplitude of bridge vibration and its infrasound.

Reception of infrasound and audio current in derma nerves

Determining the frequency range of derma nerve that responds to audio current is fundamental for the development of skin-hearing technology. Previous studies have shown that the range of derma nerve responding to audio current is 15-15 000 Hz, because audio amplification is not separated from the step-up transformer. Therefore, the present study used a signal generator which directly drives plane electrodes, simplified the original experimental environment for skin-hearing, measured lower limit voltage of frequency for derma nerve receiving pulse current signals, and revealed that the frequency range of human derma nerve response was as wide as 0.1-30 000 Hz. Results demonstrate that human derma nerve receives audio signals and infrasound within a wide frequency range.

Infrasound Signals and Their Source Location Inferred from Array Deployment in the Lützow-Holm Bay Region, East Antarctica: January-June 2015

Characteristic features of infrasound waves observed in the Antarctic represent a physical interaction relating surface environment in the continental margin and surrounding Southern Ocean. Source location of several infrasound events is demonstrated by using combination of two array deployments along a coast of the Lützow-Holm Bay (LHB), East Antarctica, for data retrieving period in January-June 2015. These infrasound arrays being established in January 2013 clearly detected temporal variations in frequency content and propagation direction of the identified seven large events. Many of these sources are assumed to have cryoseismic origins;the ice-quakes associated with calving of glaciers, discharge of sea-ice, collision between sea-ice and icebergs around the LHB. Detail and continuous measurements of infrasound waves in the Antarctic are a proxy for monitoring regional environment as well as climate change in high southern latitude.

Optimizing the PMCC Algorithm for Infrasound and Seismic Nuclear Treaty Monitoring

We introduce novel methods to determine optimum detection thresholds for the Progressive Multi-Channel Correlation (PMCC) algorithm used by the International Data Centre (IDC) to perform infrasound and seismic station-level nuclear-event detection. Receiver Operating Characteristic (ROC) curve analysis is used with real ground truth data to determine the trade-off between the probability of detection (PD) and the false alarm rate (FAR) at various detection thresholds. Further, statistical detection theory via maximum a posteriori and Bayes cost approaches is used to determine station-level optimum “family” size thresholds before detections should be considered for network-level processing. These threshold-determining methods are extensible for family-characterizing statistics other than “size,” such as a family’s collective F-statistic or signal-to-noise ratio (SNR). Therefore, the reliability of analysts’ decisions as to whether families should be preserved for network-level processing can only benefit from access to multiple, independent, optimum decision thresholds based upon size, F-statistic, SNR, etc.

Effects of Infrasound on Gastric Motility, Gastric Morphology and Expression of Nitric Oxide Synthase in Rat

Infrasound widely condition, productive exists in nature, our living and traffic environment. Gastrointestinal tract is relatively sensitive to infrasound. However, the effect of infrasound on gastrointestinal function is unclear. Therefore, the purpose of our study was to observe the effects of infrasound on gastric motiliW and gastric morphology and to assess the expression of nitric oxide synthase （NOS） in gastric antrum after exposure to infrasound of 8 Hz - 130 dB for 2 hours per day for 14 consecutive days. Gastric motility was assessed by gastric fluid-emptying rate. Gastric morphology was evaluated by HE. The expression of NOS was measured by tissue microarray technology. The results would contribute to understand the role of infrasound in gastroenterology, and help to explain the mechanism of infrasound on gastroenterology.

A Study on the Correlation of Physiological and Psychological Health Hazards in Human Habitats with Seismicity, Mountain Air Turbulence and Environmental Infrasound

A statistical correlation study on the basis of published data has been performed in order to find whether an abnormal degree of human physiological ailments and a psychology of sustained violent reactions in highly populated habitats are correlated with environmental infrasound emissions related to seismic activity and sustained by mountain air turbulence. The study focus is on Latitude 34° North coinciding with boundaries of colliding Tectonic Plates in three continents. Earthquakes, rock fractures and landslides in these regions are creating geoacoustic activity in the form of hotspots of infrasound emissions. Sources of infrasound have been located by global infrasound monitoring stations. One single earthquake can cause multiple infrasound sources in a region. Low frequency “infrasound” creates an environment of unseen and inaudible energies that are hazardous to the local population. In one region on 34°N latitude the percentage of population with hearing disabilities increases or decreases almost directly proportional to frequency of earthquakes. In this region, the casualties due to social disorder and violence increased as the frequency of earthquake events increased and decreased as this frequency decreased. Comprehensive public health studies bring out that a sizable percentage of the regional population remain in a constant state of irritation, annoyance and anger;and suffer many other psychosomatic ailments corresponding to exposure to infrasound in 5 - 16 Hz frequencies and 120 - 140 dB amplitude. A new natural hazard inimical to life on planet earth has thus been identified. The time has arrived for public health authorities to locally pinpoint infrasound hotspots by scientific measurements. Thereafter new technologies can be developed to actively, and passively, mitigate/cancel these hazardous environmental emissions of infrasound and a Public Health Security Systems put in place as sustainable solutions for a healthy, livable habitat.

Investigation of Infrasound Radiated from Highway Bridge Owing to Moving Truck

Several complaints arose from houses near an object bridge about rattling sounds caused by infrasound, a low-frequency noise in the 0 - 20 Hz frequency range. In Japan, conventional trucks with a rear leaf suspension have vibration frequencies of about 3.0 Hz;furthermore, their tire spring vibration frequency is 10 - 20 Hz. Infrasound is radiated from the bridge owing to the truck’s suspension spring vibration and/or tire spring vibration. In this study, the bridge vibrations were investigated using test trucks or conventional trucks to determine the cause of rattling sounds. It was found that the truck’s spring vibration caused excessive bending vibration in the object bridge;this in turn was transmitted to nearby houses as infrasound. Various preventive measures for infrasound were then considered, and their effectiveness was investigated through a simulation of the dynamic response using a running truck. The difference between each measure’s effectiveness as obtained by a comparison with each simulation’s result provided a clear picture about the infrasound reduction methods in consideration of both construction cost and working difficulty.

Environmental Infrasound and Its Impact on Public Health in the Kashmir Region

In earlier published studies it was shown that an anomalous degree of human physiological ailments and a psychology of sustained anger and violence exist in highly populated countries located on boundaries of colliding Tectonic Plates in three continents at Latitude 34&#176 north. The Valley of Kashmir in Northern India is also located exactly on this latitude, hence chosen for detailed experimental verification of this phenomenon. This region also suffers from chronic public health hazards. Infrasound is very low frequency acoustic wave with frequencies ranging from 0.01 Hz to 20 Hz. It emanates from earthquakes, geological Faults, colliding tectonic plates and atmospheric wind turbulence. Hearing protections like ear muffs and ear plugs offer little protection. One single earthquake can cause multiple infrasound sources in a region. It is shown how regional geomorphology in the Kashmir Valley enhances and sustains this phenomenon. Both the percentage of population with hearing disabilities;and casualties due to social violence increase or decrease in proportion to frequency of earthquakes. Infrasound is shown to be the causal linkage. Public health hazards due to environmental infrasound closely resemble public health hazards actually being suffered by the population in Kashmir as established by formal and extensive medical investigations. Hence a Field Study was carried out to locate and record infrasound emissions in ten locations near 34&#176N latitude in Kashmir Valley. An analytical technique was developed to integrate infrasound spectrum in specific locations with public health hazards. It was discovered that infrasound recorded in South Kashmir around 34&#176N latitude at the locations of highest amplitude lies in proximity of Active Faults from earthquake ruptures;and in proximity to a large field of past earthquakes that took place in 2006-2012. A comprehensive public health security system needs to be set up very urgently. Technological measures are identified and appropriate technologies suggested cordoning off and mitigating this natural environmental hazard in the Kashmir Valley.

Infrasound Signals in Coastal Environment at Jang Bogo Station, Terra Nova Bay, Antarctica

Infrasound signals in Antarctica reflect physical interaction in the surface environments around the recorded area. In December 2015, an infrasound array by three sensors in the detectable frequency range of 0.1 - 200 Hz, combined with one broadband barometer was deployed at Jang Bogo Station, Terra Nova Bay, Antarctica. The two years of data by the broadband barometer contain characteristic signals that caused by surface environment nearby the station, mixing with local noises such as katabatic winds. Clear continuous signals by oceanic swells (microbaroms) were recorded with a predominant frequency of around 0.2 s. Variations of frequency context and amplitudes in the Power Spectral Density were considered as affected by sea-ice dynamics surrounding the Terra Nova Bay. Monitoring of microbaroms could contribute to understanding ocean wave climate, with other oceanographic, cryospheric and geophysical data in Antarctica. Infrasound data in Terra Nova Bay might be a new proxy for estimating environmental variations affected by global warming, cryosphere dynamics, together with volcanic eruptions in Victoria Land.

Understanding the Split Characteristics of the Tropical Mesoscale Convective System (MCS) of April 9, 2018, in Northern Ghana Using Infrasound Data

The split characteristics of the tropical Mesoscale Convective System (MCS) of April 9, 2018, in northern Ghana were studied using infrasound data measured by the mobile array (I68CI) which was deployed by C?te d’Ivoire National Data Center (NDC) in collaboration with the Comprehensive Nuclear-Test-Ban Treaty (CTBT). These infrasound measurements were made during a measurement campaign from January 1st, 2018 to December 31, 2018, in northeast Cote d’Ivoire, precisely in Comoe National Park. Graphic Progressive Multi-Channel Correlation (GPMCC) method based on a progressive study of the correlation functions was used to analyze and visualize data. The infrasound detection from this MCS shows clearly a division of the MCS structure into 2 distinct subsystems under the effect of internal and external constraints not well known but related to convection;a smaller subsystem in the north, associated with an area of intense rainfall of about 30 mm/hour and located at 9.5°N - 2°E with an azimuth of 70° and, a large subsystem in the south, associated with a zone of high rainfall of about 96 mm/hour and located at 8.8°N - 1.4°E with an azimuth of 90°. These two subsystems were located 200 km and 260 km from the I68CI station with frequencies of 2.3 Hz and 1 Hz respectively. The mesoscale convective systems in this region are moving from East to West and including several storm cells.

Effects of On-Site Weather Conditions on the Detection Capability of the Infrasound Station of Madagascar I33MG

Noise due to surface wind and temperature is a problem in infrasound. Efficiency of IMS network concerns scientists. It is obvious to find the causes of deficiencies of detection of infrasound station by studying background noise power with respect to the surface wind and the temperature. Data measured by MB2000 microbarometer of infrasound station I33MG are used for the study. Infrasound records are separated into 4 frequency bands centered respectively at: 1 Hz, 0.25 Hz, 0.0625 Hz and 0.0156 Hz. Effects of surface wind and temperature are studied by plotting the variations of the background noise power with respect to the temperature or wind speed in the four considered frequency bands and compared with the median of background noise power. The influence of temperature is manifested by a reduction in the number of low-frequency detection. The surface wind reduces the number of detection at a high frequency. An exponential function is proposed to predict the variations of the noise power in different observation frequencies and temperature and wind conditions. The views expressed herein are those of the authors and do not necessarily reflect the views of the CTBTO Preparatory Commission.

应用原型网络的小样本次声信号分类识别方法

地震、闪电、火箭发射、爆炸等活动都会伴随着次声信号的产生。为提升次声事件的监测能力,需要对小样本的次声信号进行正确分类识别。针对小样本集的次声事件的有效识别问题,结合长短期记忆模型提出了一种应用原型网络的次声信号分类方法。使用该方法分别对公开的次声信号数据集和实地采集的地震、爆炸、闪电、火箭再入产生的4类次声信号进行分类实验。实验结果表明,该方法相对于传统方法,简化了特征提取的过程,有效解决了小样本集次声信号的特征分析问题,取得较好的分类结果和泛化效果。

泥石流次声特征分析及流量智能反演方法

次声技术已被广泛应用于泥石流监测预警中,泥石流次声的某些特征可从一定程度上反映泥石流的流量。泥石流流量是评估泥石流规模的重要参数,准确预测泥石流流量对泥石流监测预警具有重要意义。围绕影响泥石流次声特性的关键物理参量,通过定量化配比水槽实验模拟泥石流产生次声的物理过程,采集次声信号并测算流量。通过分析泥石流流量与次声之间的关联,揭示泥石流流量对次声特性的影响规律。经特征提取和特征选择提炼出可表征泥石流流量的次声特征因子并构建特征向量集。通过对比分析k近邻算法(k-nearest neighbor,KNN)、神经网络、随机森林和梯度提升决策树(gradient boosting decision tree,GBDT)算法在流量预测方面的表现性能,构建了具有较高预测准确率的泥石流流量智能反演模型。通过该智能反演模型可实现泥石流流量的有效预测,从而为泥石流次声监测提供更丰富的报警信息。

基于改进AlexNet网络的泥石流次声信号识别方法

环境干扰噪声是泥石流次声现场监测的主要挑战,极大限制了泥石流次声信号识别的准确率。鉴于深度学习在声学信号识别中的优异表现,本文提出一种基于改进的AlexNet网络的泥石流次声信号识别方法,有效提升泥石流次声信号识别准确率和收敛速度。首先对原始次声数据集进行数据扩充、滤波降噪等预处理,并利用小波变换生成时频谱图像,然后将得到的时频谱图像作为输入,通过减小卷积核、引入批量归一化层和选择Adam优化算法搭建改进的AlexNet网络模型。实验结果表明,改进的AlexNet网络模型识别准确率为91.48%,实现了泥石流次声信号的智能识别,可为泥石流次声监测预警提供高效、可靠的技术支撑。

高精度实时监测输油管道漏失报警系统G300设计

近年来,油田打孔盗油、腐蚀穿孔等输油管道泄漏事故频繁发生,由此带来了经济损失及环境污染的严重后果,为此进行了输油管道的在线监测系统研究。研制的G300管道泄漏监测报警定位系统采用自适应滤波算法和现代数字信号处理技术、模式识别算法,极大地提高了定位精度,降低了漏报率和误报率。可针对所监测管段全天候实时监测,对管道运行中发生的泄漏等异常事件进行报警、定位。与GPS为核心的定位导航系统及精确的管道电子地图相结合,可及时准确找到泄漏现场,使管道泄漏损失降到最低。试验结果表明:最小泄漏孔径为3 mm,泄漏点平均定位精度小于10 m,泄漏报警时间小于15 s,没有出现漏报情况。研制的系统可为油田输油管道的在线监测提供技术支撑。

基于BWO优化VMD联合小波阈值的管道泄漏次声波去噪方法

管道泄漏次声波信号中的干扰噪声影响管道泄漏定位的精准度。提出了一种基于白鲸优化算法(BWO)优化变分模态分解(VMD)联合小波阈值(WT)的管道泄漏次声波去噪方法。针对VMD算法中分解层数K和惩罚因子α的取值对信号分解结果影响较大,利用白鲸优化算法(BWO)对VMD分解的两关键参数进行寻优,获得最优参数组合[K、α],并利用优化后的参数对次声波信号进行VMD分解,获得一系列本征模函数(IMF)分量。通过计算各IMF分量的相关系数来区分噪声IMF分量和有效IMF分量,引入一种改进的小波阈值函数对有效的IMF分量进行去噪处理,再重构去噪后各有效IMF分量,得到去噪后的管道泄漏次声波信号。通过仿真实验,将所提方法与灰狼优化算法(GWO)优化VMD联合小波阈值和麻雀搜索算法(SSA)优化VMD联合小波阈值两种方法对比,所提方法去噪后信号的信噪比分别提高了1.27%、2.01%,表明所提方法的去噪效果具有一定的优越性,为后续管道泄漏计算定位奠定了良好的基础。