共查询到19条相似文献，搜索用时 453 毫秒
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引言建设开放性、多功能地震行业信息网络的目的 ,是为防震减灾各方面工作提供先进、高效的信息通道和平台 ,实现地震数据信息的有效管理和快速传递。因此 ,在地震信息网络系统建设中 ,必须采用标准的通讯平台 ,建立完善的网络应用环境 ,为网络用户提供信息发布工具和手段 ,并提供信息浏览服务。随着现代信息技术的高速发展和 Internet的快速普及 ,基于 TCP/IP协议的各种网络技术也得到了广泛应用。建设地震信息网络 ,可以采用成熟的 Internet技术 ,建立网络上的 WEB服务器 ,Email服务器以及代理服务器等各种服务器 ,实现地震信息的发… 相似文献
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路由器实现VPN连接及地震信息网络VPN应用分析 总被引：3，自引：0，他引：3
介绍了VPN技术和路由器实现VPN连接的建立过程。结合地震信息网络现状，分析了VPN技术应用前景，提出了基于VPN技术整合地震信息网络全国虚拟专网初步设想。 相似文献
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地震信息网络的安全运行与技术防范 总被引：2，自引：1，他引：1
地震信息网络覆盖地震监测的各类基础业务技术系统,为确保地震监测技术系统的有序和高效运行,信息网络从技术和管理两个方面采取措施,经过汶川地震考验,完成大量地震数据传输,取得较好实效。 相似文献
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为提高地震数据信息交换、管理和服务水平 ,1997年中国地震局决定在首都圈地区率先进行地震信息网络系统建设 ,并作为全国地震信息网络系统的示范工程。河北省地震信息网络作为首都圈地震信息网络系统的一部分 ,是我国首批进行建设并较早投入运行的区域地震信息网络之一。该网络系统实现了区域地震行业信息网的基本功能 ,能够提供 WEB,E- mail,ftp,Proxy和拔号访问等各种通用的 Intranet服务 ,开展了多种地震数据信息共享 ,进行了分布式数据库等各种应用研究。本系列文章讨论了该网络系统的总体构成、技术特点 ,总结了项目实施经验 ,介绍了应用研究的一些技术成果 ,通过分析系统运行效益说明地震信息网络建设与应用是实现地震数据信息共享与服务的有效手段 相似文献
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根据收集的美国FEMA等机构有关地震中信息网络运行的经验教训资料,综述了自然灾害和人为事件对信息网络系统冲击的对策研究。介绍了对一个灾难中指挥系统地震信息安全计划的自我风险评估。通过制定地震信息安全收集和传播计划,有效降低信息网络管理的风险。详细介绍了指挥系统信息网络的地震信息安全计划、突发事件响应计划和灾难恢复计划的编制程序。 相似文献
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WLAN技术在黑龙江省地震信息网络中的应用 总被引：1，自引：0，他引：1
本文介绍了无线局域网（WLAN）的概念和主要技术特点，在此基础上给出了黑龙江省地震信息网络应用WLAN技术的解决方案，并对关键技术进行了分析。 相似文献
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随着因特网技术的广泛应用和发展,信息网络的安全越来越受到关注和重视.同样,山西地震信息网络也受到了较大的安全威胁.指出从选用安全的口令、实施存取控制、保障数据的完整性和安全、做好数据的备份、使用防火墙和安装防病毒软件等措施可确保山西地震信息网络的安全正常运行. 相似文献
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广州数字地震台IP传输质量分析 总被引：1，自引：0，他引：1
概述广州数字地震台数据传输的现状和IP传输技术的应用。详细介绍了IP Data Terminal地震数据传输终端的功能和特点。分析了167天来广州台DDN传输与IP传输对比观测的结果,结果表明,DDN传输受天气影响较大,而IP传输波形误码率低,并受益于“断点续传”,使波形连续率逐步提高。对IP数据传输的质量进行了分析,并对将来用IP传输代替DDN传输提出了建议。 相似文献
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D.C. FRASER 《Geophysical Prospecting》1981,29(4):639-651
Dipole-dipole induced polarization (IP) data are displayed typically as multi-level profiles, or as contours on vertical sectional plots referred to as pseudo-sections. The dipole-dipole array tends to yield IP anomalies in which the most anomalous values are displaced laterally from the source body. The data patterns are fairly interpretable on pseudo-sections or on multi-level profiles but are sufficiently complex to discourage the contouring of the data in plan. A method was developed for the presentation of dipole-dipole IP data on a contour map. The method consists of a simple averaging of data which can be performed manually if desired. It yields a single output value per station which reflects all levels of the pseudo-section, and is suitable for contouring in plan. The advantage of the technique is that it provides a quantitative picture of IP anomalies in their background or regional setting. 相似文献
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《Journal of Applied Geophysics》1999,41(1):31-47
The Idaho National Laboratory (INEL) Cold Test Pit (CTP) has been carefully constructed to simulate buried hazardous waste sites. An induced polarization (IP) survey of the CTP shows a very strong polarization and a modest resistivity response associated with the simulated waste. A three-dimensional (3-D) inversion algorithm based on the simultaneous iterative reconstruction technique (SIRT) and finite difference forward modelling has been applied to generate a subsurface model of complex resistivity. The lateral extents of the waste zone are well resolved. Limited depth extent is recognized, but the bottom of the waste appears too deep. With a modelling experiment, the intrinsic polarizability of the waste material is determined. Since IP is a technique for detection of diffuse occurrences of metallic material, this method holds promise as a method to distinguish buried waste from conductive soil material. 相似文献
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Vegetation responses to integrated water management in the Ejina basin,northwest China 总被引：1，自引：0，他引：1
The Ejina basin, which is located in arid and semi‐arid areas of northwest China, has experienced severe environmental deterioration in the past several decades, and an exploratory project was launched by the Chinese Government in 2001 to restore this degraded ecosystem. In this study, multi‐scale remotely sensed data and field investigations were used to quantify the responses of vegetation to the implementation of integrated water management under this project. In terms of the seasonal accumulated Normalized Difference Vegetation Index (SAN) variation, (1) the vegetation in 80·4% of the oasis regions showed an increasing or recovering trend, and increasing SAN trends with a magnitude greater than 0·14 a?1 mainly resulted from cultivated land reclamation; (2) the vegetation in 91·5% of the desert regions presented an increasing trend, and the statistically significant trends mainly appeared in the middle and lower Ejina basin; (3) the vegetation in 19·6% of oasis and 5·1% of desert regions showed a decreasing or degrading trend, mainly where rivers diminished and along artificial concrete canals; and (4) opposite signs of vegetation trends occurred simultaneously along some natural rivers experiencing water reduction, with a decreasing trend generally appearing in the high SAN regions, whereas an increasing trend was seen in the low SAN regions. The broad vegetation recovery observed was due to the comprehensive improvement of the water environment, which was attributed to both the increase in runoff entering the Ejina basin and the adoption of engineering measures. Vegetation degradation in the area mainly resulted from deterioration of the local water environment, which was closely related to the problems of water management. The results of this study can be used as a reference for adjusting the current water resource management strategy to effectively restore this ecosystem. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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We measured Spectral Induced Polarization responses of 22 models of disseminated ore with a time domain (TD) technique. The models were mixtures of calibrated sand (0.2–0.3 mm) with calibrated ore grains (average radii: 0.045, 0.055, 0.13, 0.20, 0.38 and 0.55 mm). The grains represent a mixture of pyrrhotite (30%), pyrite (30%), magnetite (30%) and chalcopyrite (10%) coming from a natural ore. In the models, the grain concentration (by volume) varied between 0.6 and 30%.We obtained IP decays with a conventional field TD measuring technique and a lab low-current transmitter in the time range from 0.3 ms to 64 s. The IP decays measured with various current wavelength forms were inverted to relaxation time distributions (RTD) on the basis of the Debye decomposition approach.RTD parameters were found to be closely related to the ore volumetric content and the ore grain size. The total chargeability is independent of the grain size, but is determined by the grain volume fraction. In contrast, the mean IP relaxation time is related to the grain size. These facts make RTD attractive to use in ore prospecting and studying reactive permeable barriers.Moreover, for low salinity pore water used in this study, the relaxation times of disseminated ores are three to four decades smaller than that of the insulating grains of the same size typical of common soils and sediments. This allows recover the relaxation times on the basis of relatively fast IP measurements with short time pulses (in TD) or high frequency values in the frequency domain; however attention should be paid to inductive and capacitive couplings. 相似文献
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Theoretical and experimental study of time domain-induced polarization in water-saturated sands 总被引：1，自引：0，他引：1
A theoretical model of spectral-induced polarization (IP) of sand is presented. In the proposed model, contacts of sand grains and intergrain solution-filled space are considered as electrical current passages of varying thickness, which differ in values of ion transport number. Ion-selective narrow passages are considered as active zones, large passages as passive. The proposed model describes spectral IP characteristics for the medium where the length of passive zones is much greater than the length of active ones. The model is called short narrow pores (SNP) model. The SNP model predicts a growth of IP time constant with increase of length of ion-selective zone. Both the time domain and frequency domain parameters are described. The parameters of Cole–Cole model corresponding to the SNP model were also found.The behaviour of model parameters is compared with experimental data obtained on natural and sieved sands using time domain technique. The natural sand spectra correspond neither to the simple SNP model nor simple Cole–Cole model with single time constant because the lengths of ion-selective zones vary, reflecting the grain-size distribution.The spectra of sieved sand compared with the theoretical SNP spectra reveal close correspondence between experimental data and theoretical parameters. For four sieved sands, both the theoretical and experimental data show that the time constant of the IP is proportional to the square of the average grain size. 相似文献
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《Marine pollution bulletin》2013,69(1-2):77-84
The waters of the Cres–Lošinj archipelago are subject to intense boat traffic related to the high number of leisure boats frequenting this area during the summer tourist season. Boat noise dominates the acoustic environment of the local bottlenose dolphin (Tursiops truncatus) population. This study investigates the spatial and temporal change in the underwater noise levels due to intense boating, and its effect on the distribution of the bottlenose dolphins. In the period 2007–2009 sea ambient noise (SAN) was sampled across ten acoustic stations. During data collection the presence of leisure boats was recorded if they were within 2 km of the sampling station. Bottlenose dolphin spatial distribution was monitored in the same period. Results showed a strong positive correlation between high SAN levels and boat presence, particularly in the tourist season. Dolphin distribution indicated significant seasonal displacements from noisy areas characterized by the intense leisure boating. 相似文献