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401.
Many studies have been conducted to investigate thephysicochemical behavior of pure clay minerals and predicttheir engineering performance in the field. In this study, thephysicochemical properties of an artificial mixture of differentclay minerals namely, 40-50% montmorillonite, 20-30% illite and 10-15% kaolin were investigated. The mixture was homoionized with sodium, Na+; calcium, Ca2+; andaluminum, Al3+. The engineering properties studied wereconsistency limits, sediment volume, compressibility behavior,and hydraulic conductivity. The results revealed that theliquid, plastic and shrinkage limits of soil increased withincreasing cation valence. The hydraulic conductivity of thesoil also increased with an increase in the valence of thecation at any given void ratio. Aluminum and sodium treatedclays had the highest and the lowest modified compressionindex values, respectively. Furthermore, trivalent cationsaturated clayey soil consolidates three times faster thanthat of monovalent and two times faster than that of divalent.These properties of the soils determined were, in general,similar to those of kaolinite rather than those ofmontmorillonite. The comparison of the results obtained withthe published data in the literature revealed that thephysicochemical behavior of the tested clay soil was, ingeneral, similar to that of kaolinite.  相似文献   
402.
为了预测并控制未来几年城市垃圾产量,以我国城市为例,利用K-近邻互信息的多变量特征从18个拟影响因素中确定了8个影响垃圾排放量因子,分别为常住人口、地区生产总值、社会消费品零售值、金融业增加值、工业增加值、批发和零售业增加值、住宿和餐饮业增加值和第三产业增加值.以2006~2013年数据为训练样本,2014~2015年数据为检验样本,根据影响因素建立径向基函数(RBF)神经网络预测模型,并基于平均相对误差对模型反向修正.然后结合两段式径向基预测模型,对全国各省市2017~2018年的垃圾总产量预测并可视化.结果表明,本文建立的两段式径向基预测模型平均相对误差是6.43%,预测精度为93.57%.可见,该模型的预测精度较高,能较好的在现实生活中对城市垃圾的产生量进行预测.  相似文献   
403.
信息系统安全风险评估研究综述疆   总被引:14,自引:3,他引:14  
风险评估是信息系统安全保证的关键技术。笔者对国内外现有的信息安全风险评估方法与技术进行归纳和系统的评述。回顾了信息安全风险评估的理论框架与现有的评估标准;在此基础上,比较了包含FTA,FMECA,HAZOP等在内的传统风险评估技术和以CORAS为代表的现代风险评估技术;肯定了现代风险评估技术在利用统一建模语言进行半形式化表述方面的先进性以及根据信息系统生命周期的各个阶段特点选用适宜的风险评估方法的灵活性;同时指出该现代风险评估技术在动态识别、评估安全风险方面的不足;提出了一种改进和完善现代风险评估技术的方法,即利用Markov链形式化描述并分析信息系统,确保了分布式信息系统风险评估的需要。此外,针对信息安全风险的不确定性,提出了通过模糊集理论丰富现代风险评估方法的研究方向。  相似文献   
404.
信息不对称条件下企业物流外包过程的风险和防范   总被引:32,自引:0,他引:32  
结合信息不对称理论 ,研究了物流外包过程中风险产生的途径和规律 ,从对第三方物流企业依赖程度入手 ,分析了多重外包、分散外包的风险模型讨论 ,提出了抽象的物流量的概念 ,将复杂的物流作业看成是量化了的、一般的物流作业。通过分析风险的成因 ,提出了 1 0种降低外包风险的途径 ,为企业物流外包决策提供参考。  相似文献   
405.
资源和环境问题是我国面临的严重的生态安全和环境安全问题,也是制约我国工业可持续发展的战略问题。生态铝业是与环境协调发展的环境友好的工业体系,它有效地解决了传统铝业发展和生态环境保护之间的矛盾。传统铝业耗电量大、污染严重、生产成本高;现代铝业属于生态工业,它以循环经济为指导,推行清洁生产,发展热电联产,促进污染物的资源化,减少废弃物的排放,降低了铝业生产的物耗、能耗和生产成本,增加了市场竞争力,形成整个工业系统的良性循环。笔者提出了现代铝业生态系统的框架,并简单介绍了主要子系统的清洁生产途径。以期抛砖引玉,促进现代铝业生态环境系统的研究,推动生态铝业在我国的实践和发展。  相似文献   
406.
介绍了安全监控系统的基本概念、特点以及国内外研究现状,给出了智能安全监控系统的基本结构,包括信息采集、信息处理、信息融合和安全监控报警等模块。构建了综合的智能安全监控自动化系统。智能安全监控自动化系统,是多学科知识融合的产物。对该领域进行深入的研究,必须综合先进的自动控制技术、计算机技术、智能传感器技术、通信技术以及信息处理技术等成果。指出了基于信息融合的智能安全监控系统的几个重要研究方向,即新型智能传感器技术、先进的信息处理与传输技术、先进的信息融合方法以及相应的软件系统开发。创造性地提出了安全监控信息融合方法的融合以及多学科知识和技术的融合。  相似文献   
407.
地震次生火灾对人类的危害极大.本文在对以往历史数据的统计基础上,模拟出城市每10万平方米建筑地震次生火灾发生件数与地震地面加速度峰值的关系,并由此计算了地震后火灾发生的件数.  相似文献   
408.
What is the relationship between biotechnology employees’ beliefs about the moral outcomes of a controversial transgenic research project and their attitudes of acceptance towards the project? To answer this question, employees (n=466) of a New Zealand company, AgResearch Ltd., were surveyed regarding a project to create transgenic cattle containing a synthetic copy of the human myelin basic protein gene (hMBP). Although diversity existed amongst employees’ attitudes of acceptance, they were generally: in favor of the project, believed that it should be allowed to proceed to completion, and that it is acceptable to use transgenic cattle to produce medicines for humans. These three items were aggregated to form a project acceptance score. Scales were developed to measure respondents’ beliefs about the moral outcomes of the project for identified stakeholders in terms of the four principles of common morality (benefit, non-harm, justice, and autonomy). These data were statistically aggregated into an Ethical Valence Matrix for the project. The respondents’ project Ethical Valence Scores correlated significantly with their project acceptance scores (r=0.64, p<0.001), accounting for 41% of the variance in respondents’ acceptance attitudes. Of the four principles, non-harm had the strongest correlation with attitude to the project (r=0.59), followed by benefit and justice (both r=0.54), then autonomy (r=0.44). These results indicate that beliefs about the moral outcomes of a research project, in terms of the four principles approach, are strongly related to, and may be significant determinants of, attitudes to the research project. This suggests that, for employees of a biotechnology organization, ethical reasoning could be a central mechanism for the evaluation of the acceptability of a project. We propose that the Ethical Valence Matrix may be used as a tool to measure ethical attitudes towards controversial issues, providing a metric for comparison of perceived ethical consequences for multiple stakeholder groups and for the evaluation and comparison of the ethical consequences of competing alternative issues or projects. The tool could be used to measure both public and special interest groups’ ethical attitudes and results used for the development of socially responsible policy or by science organizations as a democratizing decision aid to selection amongst projects competing for scarce research funds.  相似文献   
409.
ABSTRACT: LIDAR is relatively new in the commercial market for remote sensing of topography and it is difficult to find objective reporting on the accuracy of LIDAR measurements in an applied context. Accuracy specifications for LIDAR data in published evaluations range from 1 to 2 m root mean square error (RMSEx,y) and 15 to 20 cm RMSEz. Most of these estimates are based on measurements over relatively flat, homogeneous terrain. This study evaluated the accuracy of one LIDAR data set over a range of terrain types in a western river corridor. Elevation errors based on measurements over all terrain types were larger (RMSEz equals 43 cm) than values typically reported. This result is largely attributable to horizontal positioning limitations (1 to 2 m RMSEx,y) in areas with variable terrain and large topographic relief. Cross‐sectional profiles indicated algorithms that were effective for removing vegetation in relatively flat terrain were less effective near the active channel where dense vegetation was found in a narrow band along a low terrace. LIDAR provides relatively accurate data at densities (50,000 to 100,000 points per km2) not feasible with other survey technologies. Other options for projects requiring higher accuracy include low‐altitude aerial photography and intensive ground surveying.  相似文献   
410.
This paper focuses attention on emergency management associated with a terrorist attack in the transport of hazardous materials in urban areas. The case study is in an urban area, a potential target for terrorist attacks due to its high vulnerability. Since it is not possible to predict where and when an attack will occur, the risk associated with terrorism is complex. It is only possible to identify the critical points for potential actions where counter measure must be applied. In the case of incidents which evolve relatively slowly, mitigation actions can be applied. The use of dynamic geoevents permits the immediate location of the event on a georeferenced map and the possibility of having a dynamic evolution of the scenario and of the number of people involved. The dynamic scenario has been created using the output of a consequence simulation code and a GIS software. Some assumptions were necessary but, since the aim of the paper is to define the procedure for the construction of the dynamic geoevent, these can be considered acceptable. The method will be further implemented in future.  相似文献   
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