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网络在给人们工作、生活带来便捷的同时,也产生了一些消极影响。通过分析网络安全面临的挑战及其表现形式,从技术层面提出有效保护网络安全的有效途径。 相似文献
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通过浮顶油罐浮顶焊缝断裂漏油的实例,从油罐设计、施工、检修和油罐运行管理四个方面对浮顶焊缝断裂的原因,作了较详细的分析,同时提出了防止焊缝断裂的整治措施,主要从油罐设计、大修时的补救及油罐的日常运行管理等三个方面进行了探讨。 相似文献
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在我国寒冷地区,冬季建筑工程施工常常出现质量问题,即易出现混凝土裂缝和钢筋锈蚀等现象.该文有针对性地论述了三种预防措施. 相似文献
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T. J. Marjomäki 《Ecology of Freshwater Fish》2004,13(1):46-60
Abstract – Spawning biomass and recruitment data for vendace from a central Finnish lake were analysed by fitting various recruitment models and comparing the fits statistically. The compensatory models of Ricker, Cushing and Beverton & Holt fitted the data better than the H 0 hypothesis of constant proportionality, but model and parameter uncertainties were high. Additional variables were included in an attempt to reduce uncertainties. Heavy wind forcing during the first month after hatching of larvae reduced the recruitment success. For the Ricker and the Cushing models, recruitment seemed to be also negatively associated with the density of the previous year-class. The r 2 increased considerably with inclusion of these additional variables, but the precision of model parameters remained low. Monte Carlo simulation of a vendace stock was applied to evaluate the interference of biases from the measurement error (ME) and time series error (TSE) in the analysis. Especially in the case of the Cushing model, compensatory density dependence can be overestimated severely. Increasing the number of observations decreases the biases in some cases. In view of potential biases and uncertainties, a precautionary management policy is recommended. 相似文献
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区域性沙尘天气预警系统的开发与应用 总被引:3,自引:0,他引:3
综述了目前国内外沙尘天气监测及预警的研究现状,进而阐述了区域性沙尘天气预警系统设计的目标及意义、系统设计方案、系统结构与功能,介绍了环北京地区沙尘天气预警系统与内蒙古地区沙尘天气预警系统两个应用实例,最后讨论了预警系统后期待完善的设计思路及目标。 相似文献
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Is risk consistent across tier‐based harvest control rule management systems? A comparison of four case‐studies
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Catherine M Dichmont André E Punt Natalie Dowling José A A De Oliveira Lorne R Little Miriana Sporcic Elizabeth Fulton Rebecca Gorton Neil Klaer Malcolm Haddon David C Smith 《Fish and Fisheries》2016,17(3):731-747
There can be substantial differences in data quality and quantity among fished species. Consequently, the quality and type of assessments can also vary substantially. However, all species, especially those that are targeted, need to be managed. Several jurisdictions have developed hierarchical tier systems that categorize stocks based on, for example, the data available for assessment purposes and/or the extent to which quantities on which management advice is based can be estimated. Four case‐studies (Australia's Southern and Eastern Scalefish and Shark Fishery, the USA west coast groundfishery, the USA Alaskan crab fishery and EU fisheries) are used to contrast the types of hierarchical tier systems available, and to assess the extent to which each system constrains risk to be equivalent among the tiers (termed risk equivalency). Only the Australian system explicitly aims to achieve risk equivalency. However, this intent has not been fully operationalized. Our review reveals that best practice is not to define tiers simply on data availability, but also on what the assessments based on those data are capable of estimating. In addition, clearly differentiating the quantification of uncertainty from how decision‐makers wish to address that uncertainty would simplify justification of buffers (the gap between the assessment‐produced target catch or effort and the final management decision that accounts for uncertainty and risk). Risk equivalency can be achieved using management strategy evaluation to select the values for control variables, which determine the buffer given the uncertainty associated with the assessment. 相似文献
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风险防范原则在外来物种入侵立法中的适用 总被引:2,自引:1,他引:1
讨论风险防范原则在我国外来物种入侵立法中的适用,并提出了相应的管理基本思路。 相似文献
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概述会计信息的定义、特征及作用;阐述会计信息失真的涵义、类型、特点、手段及具体表现;指出其对经济秩序乃至整个社会的危害;并针对目前我国经济管理活动中会计信息失真的现状、探索防范与治理策略。 相似文献