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911.
912.
为进一步提高国内基础建模数据质量,降低建模实践中的数据清洗难度,本研究以北京龙庆再生水厂生物建模过程中的实际数据问题为例,基于数理统计理论及国内污水水质特征分别构建误差来源分析方法与误差影响评价方法.通过设计补充采样与实验排查方案,成功识别数据误差来源并实现不同类型误差对数据准确性的影响量化评价.研究结果表明,污水处理厂日常的取样与化验过程中产生的随机误差不可忽视,特别是当大量随机误差存在时,对数据总体造成的波动影响无法通过数据量的积累而消除;而不同的采样位置与不当的样品保存方式则会引起水质发生变化,由此产生的系统误差将导致测量结果长期偏高/偏低.因此,在依赖人工测量数据进行建模的国内实践中,应首先对历史数据进行误差检验,再进行必要的建模补充采样,以避免补充数据质量受相同误差影响,减少非必要的人力、物力浪费. 相似文献
913.
914.
广州垃圾填埋渗滤液中有机污染物的去除效果 总被引:16,自引:2,他引:14
采用同时好氧厌氧生物反应器处理广州市大田山垃圾填埋渗滤液,平均出水浓度CODCr为131mg·L-1,氨氮为7mg·L-1,达到了同类废水的国家二级排放标准.同时选择GC-MS联用仪对垃圾渗滤液中的有机物进行测定,测得有机污染物87种,其中16种有机污染物被列入美国EPA环境优先控制污染物,31种有机物被完全去除,14种有机物去除率可达80%以上,25种有机物去除率达50%以上. 相似文献
915.
We present a method for detecting the zones where an irregularly sampled variable changes abruptly in the plane. Such zones
are called Zones of Abrupt Change (ZACs). This method not only allows estimation of ZACs, but also testing of their statistical
significance against the null hypothesis of a stationary correlated random field. The sampling pattern, in particular its
local density, is crucial in the detection of potential ZACs. In this paper, we address the problem of evaluating the sampling
pattern by assessing the power of the local test used for detecting ZACs. It is shown that mapping the power allows us to
identify zones where ZACs may or may not be detected. The methodology is applied to a soil data set sampled at eight different
dates in an agricultural field. Detecting ZACs for the soil water content allowed us to identify permanent structures in the
agricultural field related to the boundaries between different soil types. Mapping the power for various sampling densities
proved to be useful to determine the minimal sampling density necessary for detecting ZACs.
相似文献
Edith GabrielEmail: |
916.
917.
This study describes the deforestation impact from three settlements, 5 de Junio, El Tigre, and 30 de Agosto, near the Madidi National Park in Bolivia. First deforestation rates along the road that connects the settlements and then deforestation within each settlement are examined. Landsat Thematic Mapper (TM) imagery from 1987, 1997, and 2000 were used to measure the deforestation. Face-to-face interviews were also used to collect detailed social and land-use information. Road-building and farming have been the major causes of deforestation in this region. The TM measurements indicate a high increase in the deforestation rate along the road in the area of study. The results also show a rapidly escalating deforestation rate in 5 de Junio, a potential high future deforestation rate in El Tigre, and a gradual deforestation increase in 30 de Agosto. The information provided by the settlers about clearing was compared with the imagery analysis. Generally, the settlers estimates were lower than the deforestation as derived from the imagery. 相似文献
918.
919.
V. Ebrahimipour K. Suzuki A. Azadeh 《Journal of Loss Prevention in the Process Industries》2006,19(6):542-552
Automated controlled systems are vulnerable to faults. Faults can be amplified by the closed loop control systems and they can develop into malfunction of the loop. A control loop failure will easily cause production stop or malfunction at a petrochemical plant. A way to achieve a stable and effective automated system is to enhance equipment dependability. This paper presents a standard methodology for the analysis and improvement of pump performance to enhance total operational effectiveness and stability in offshore industry based on dependability. Furthermore, it is shown how a reliability–safety analysis can be conducted through equipment dependability indicators to facilitate the mitigation of hazard frequency in a plant. The main idea is to employ principle component analysis (PCA) and importance analysis (IA) to provide insight on the pumps performance. The pumps of offshore industries are considered according to OREDA classification. The approach identifies the critical pump and their fault through which the major hazards could initiate in the process. At first PCA is used for assessing the performance of the pumps and ranking them. IA is then performed for the worst pump which could have most impact on the overall system effectiveness to classify their components based on the component criticality measures (CCM). The analysis of the classified components can ferret out the leading causes and common-cause events to pave a way toward improving pump performance through design optimization and online fault detection which ultimately enhance overall operational effectiveness. 相似文献
920.
无损检测法是一种常用的故障诊断技术,故障诊断从本质上来讲就是模式识别问题,而模式识别又可以狭义地理解为图像识别。从介绍图像、图像识别、图像识别过程和图像识别系统的基本概念着手,就几种常用图像识别方法的原理和特点进行比较,给出了CCD图像获取系统的组成。最后,结合发动机曲轴的一种自动磁粉探伤系统实例,对系统的图像处理和识别流程进行详细的讨论,并针对一般无损检测系统难以满足曲轴的检测要求和精度要求的状况,提出经过改进的一种适用于曲轴的整体无损检测系统。该系统有助于高效和完整地获取整个曲轴的图像,提高图像信息的质量,从而提高发动机曲轴表面缺陷检测的准确性和可靠性。 相似文献