共查询到19条相似文献，搜索用时 156 毫秒
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针对当前测震台网及大震现场流动监测中使用拨号链路及无线传输链路进行数据传输时的不足之处,提出了基于宽带卫星的地震数据传输方案.并以IPSTAR宽带卫星为例分析了几种地震数据传输的典型应用,对我国的流动地震监测台站建设及水库地震台网建设具有一定的借鉴意义.实验结果表明,基于宽带卫星的数据传输在应对中强地震现场应急流动监测及偏远地区水库地震监测方面具有适应性强,成本低廉,架设方便可靠等优点,作为现有地震监测数据传输方式的补充,具有不可替代的作用. 相似文献
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准确及时地获取地震前兆数据是开展地震短临预报和科学研究的重要基础。文中在详尽分析Oracle高级队列技术原理的基础上,给出了数据传输模型;分析了地震前兆数据的特点和传输要求;对比了已有的数据传输手段,如高级复制、E-mail,FTP等。通过PL/SQL语言编程实现了运用Oracle高级队列技术传输地震前兆数据的实例,认为利用Oracle高级队列技术进行地震数据传输是完全可行的,非常适合在地震业务处理系统中使用,为“十五”“中国地震信息服务系统”项目建设提供了一种新的数据传输手段 相似文献
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准确及时地获取地震目录是开展地震短临预报和科学研究的重要基础。本文在详尽分析Oracle高级队列技术原理的基础上，并参考了已有的地震目录传输方法，给出了数据传输模型；通过PL／SQL语言编程实现了运用Oracle高级队列技术传输地震目录数据的实例，认为利用Oracle高级队列技术进行地震目录传输是完全可行的，非常适合在地震业务处理系统中使用，为地震目录的传输提供了一种新的手段。 相似文献
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主要从Miniseed格式以及Steim算法的相关原理出发,分析单台1 s理论最大和最小数据量。根据福建台网数据,对各种仪器取样,然后取平均,得出实际每个包数据量的一般值和最大值。根据现有数据传输方式,除去传输中的理论损耗,计算相关带宽对应的最大数据传输量。在得出地震数据单台1 s数据临界值和带宽最大传输量的情况下,总结计算结果,得出测震传输网络传输带宽临界值。 相似文献
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从宁夏地震监测台网实际出发,以地震监测数据采集交换系统为研究对象,以现有的监测工作流程和模式为基础,利用物联网这一目前较为先进的网络架构设计手段,综合运用中间件等技术构建了一套基于物联网架构的集数据采集、数据传输、数据处理和数据分析决策为一体的地震监测及应急调度系统. 相似文献
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Accurate calculation of the solar radiation at the earth’s surface requires evaluation of the atmospheric ozone transmission. To use the existing methods one needs to know the atmospheric ozone amount. The serious lack of ozone data makes almost impossible the application of these methods in most of the world. In this paper a new method of estimating the overall ozone attenuation in the Northern Hemisphere is presented. Multiyear monthly latitudinal average ozone data are used. A daily ozone transmission function is proposed, and values of it are calculated for each latitudinal circle from 0° to 70°N at 10 longitude-degree intervals. By regression techniques parameterized expressions of the daily ozone transmission in the Northern Hemisphere are obtained as a function of the latitude. The model is applied to Athens, and the results are in excellent agreement with those obtained by extremely detailed calculations of the ozone transmission. The reliability of the model, under special regional ozone conditions, is investigated. Calculations for 67 locations in the Northern Hemisphere prove that the deviations do not exceed 1 percent. The influence of the year-by-year ozone variability is also examined, and the maximum deviation is found to be near 1.6 percent. The proposed model can be easily incoporated into solar radiation models in order to provide the ozone depletion at any place in the Northern Hemisphere where atmospheric ozone data are not available. 相似文献
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随着数字地震台站数量的增加、数据传输手段的多样化以及地震预警系统的发展,对地震数据实现有效的实时压缩对数据传输显得十分重要.本文提出一种支持低时间延迟(数据传输间隔小于1 s)数据传输要求的实时数据压缩算法.通过理论估算和实际地震数据检验,该方法高效、易实现,适用于地震预警等领域. 相似文献
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SEED格式STEIM2数据压缩算法在实时地震数据传输中的应用 总被引：9，自引：1，他引：8
在一定带宽内,及时、高效、无失真地传输地震数据是地震数据传输的基本要求,SEED格式给出的数据格式在数据压缩方面有其独到之处,但SEED格式没有定义数据正确性和完整性保证机制和检验方法,因而影响实时传输中的使用。本文提出一种基于SEED格式的STEIM2数据压缩算法,同EDAS数据包形式兼容的实时压缩数据包编码方法,来实现实时压缩数据的传输。经理论评估和实际数据检验,它容易实现,效率高,安全,可靠,完全可以应用于实时数据传输。 相似文献
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2008年5月12日汶川8.0级特大地震,是继1976年唐山大地震后的又一人间悲剧。灾难过后,痛定思痛,如何保证在非常时期将地震数据可靠地传输回台网管理中心,为研究人员提供完整的数据波形,是地震观测技术人员在这次地震后应该慎重思考的问题之一。本文收集比较了中国地震部门常用的4种地震数据传输方式在8.0级特大地震中的表现,供同行参考。 相似文献
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山东数字化水位观测开展了近3年时间，与模拟观测相比，具有数据传输快、数据量级大、人为误差少的优点，从而使地下水位的高频、短周期信息大量增加，为捕捉地震短临异常信息提供了有利条件。分析结果表明，数字化水位观测资料与模拟观测资料的变化特征一致，因而可以代替现有的模拟观测；数字化水位观测资料保存在SQLserver数据库，可通过地震前兆信息处理与软件系统（EIS2000）方便地联接，随时采用相关的数学处理方法分析，跟踪动态的发展变化；日常分析应用表明，数字化水位观测资料仍可延用以往模拟观测资料的分析处理方法，同时许多新方法（如潮汐分析、加卸载响应比法）也可在数字化水位观测资料分析中应用。 相似文献
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We test various methods of quantifying the compliance of single and multiple rock fractures from synthetic ultrasonic data. The data are generated with a 2D discrete particle scheme which has previously been shown to treat fractures in agreement with linear-slip theory. Studying single fractures, we find that delays derived from peak amplitudes do not correspond to group delays, as might be expected. This is due to waveform distortion caused by the frequency-dependent transmission across the fracture. Instead the delays correspond to an expression for phase delays, which we derive from linear-slip theory. Phase delays are a unique function of compliance, whereas group delays are non-uniquely related to compliance. We believe that this property of group delays has hindered the wider application of deriving fracture compliances from traveltimes. We further show that transmission coefficients derived from waveform spectra yield more accurate fracture compliances than those obtained from ratios of signal peak amplitudes. We also investigate the compliance of a set of parallel fractures. Fracture compliance can only be determined from transmission coefficients if the fracture spacing is so large that the first arriving pulse is not contaminated by reverberations. In the case of contamination the direct measurement of group or phase delays is not practical. However, we demonstrate that in such cases of strong waveform distortion the coda wave interferometry method is very effective for determining relative fracture compliance. First break delays in the fracture set data are related to those observed in single fracture simulations. This means that fracture set compliance can be estimated from first break data if used together with numerical simulations. 相似文献
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Accurate sonar performance prediction modelling depends on a good knowledge of the local environment, including bathymetry,
oceanography and seabed properties. The function of rapid environmental assessment (REA) is to obtain relevant environmental
data in a tactically relevant time frame, with REA methods categorized by the nature and immediacy of their application, from
historical databases through remotely sensed data to in situ acquisition. However, each REA approach is subject to its own
set of uncertainties, which are in turn transferred to uncertainty in sonar performance prediction. An approach to quantify
and manage this uncertainty has been developed through the definition of sensitivity metrics and Monte Carlo simulations of
acoustic propagation using multiple realizations of the marine environment. This approach can be simplified by using a linearized
two-point sensitivity measure based on the statistics of the environmental parameters used by acoustic propagation models.
The statistical properties of the environmental parameters may be obtained from compilations of historical data, forecast
conditions or in situ measurements. During a field trial off the coast of Nova Scotia, a set of environmental data, including
oceanographic and geoacoustic parameters, were collected together with acoustic transmission loss data. At the same time,
several numerical models to forecast the oceanographic conditions were run for the area, including 5- and 1-day forecasts
as well as nowcasts. Data from the model runs are compared to each other and to in situ environmental sampling, and estimates
of the environmental uncertainties are calculated. The forecast and in situ data are used with historical geoacoustic databases
and geoacoustic parameters collected using REA techniques, respectively, to perform acoustic transmission loss predictions,
which are then compared to measured transmission loss. The progression of uncertainties in the marine environment, within
and between different REA categories, and the consequences on acoustic propagation are examined. 相似文献
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Tomography is widely used in geophysics as a technique for imaging geological structures by means of data that are line integrals of physical characteristics. In some transmission measurements, due to various kinds of normalization, the measured data are related to two (the current and the reference) raypaths and can be expressed as a function of differences between line integrals. This is the case, for example, in seismo-acoustic emission measurements, when (since the exact start time is unknown) only the differences between traveltimes (differences between line integrals of the slowness) can be determined. Similarly the use of normalized Fourier amplitudes results in data dependent upon the difference between line integrals of the absorption coefficient (computed along the actual and the reference raypaths). In order to invert these data the ordinary tomography algorithms should be modified. Some generalizations are presented for series expansion tomography methods in order to make them applicable to reconstruction problems in which the input data are differences between two line integrals. The conjugate gradient and the simultaneous iterative reconstruction technique (SIRT) methods were adapted and tested. It is shown that the modified tomography algorithms are stable and sufficiently accurate for practical use. In the reconstruction of noise-free difference data, the conjugate gradient algorithm is found to be faster and more accurate while, in the case of noisy difference data, the modified SIRT algorithm is more stable and insensitive to noise. 相似文献