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531.
Jean-Sauveur Ay Raja Chakir Julie Le Gallo 《Environmental Modeling and Assessment》2017,22(2):129-145
The objective of this paper is to compare the predictive accuracy of individual and aggregated econometric models of land-use choices. We argue that modeling spatial autocorrelation is a comparative advantage of aggregated models due to the smaller number of observation and the linearity of the outcome. The question is whether modeling spatial autocorrelation in aggregated models is able to provide better predictions than individual ones. We consider a complete partition of space with four land-use classes: arable, pasture, forest, and urban. We estimate and compare the predictive accuracies of individual models at the plot level (514,074 observations) and of aggregated models at a regular 12 × 12 km grid level (3,767 observations). Our results show that modeling spatial autocorrelation allows to obtain more accurate predictions at the aggregated level when the appropriate predictors are used. 相似文献
532.
This paper presents monitoring results of daily brick kiln stack emission and the derived emission factors. Emission of individual air pollutant varied significantly during a firing batch (7 days) and between kilns. Average emission factors per 1,000 bricks were 6.35–12.3 kg of CO, 0.52–5.9 kg of SO2 and 0.64–1.4 kg of particulate matter (PM). PM emission size distribution in the stack plume was determined using a modified cascade impactor. Obtained emission factors and PM size distribution data were used in simulation study using the Industrial Source Complex Short-Term (ISCST3) dispersion model. The model performance was successfully evaluated for the local conditions using the simultaneous ambient monitoring data in 2006 and 2007. SO2 was the most critical pollutant, exceeding the hourly National Ambient Air Quality Standards over 63 km2 out of the 100-km2 modelled domain in the base case. Impacts of different emission scenarios on the ambient air quality (SO2, PM, CO, PM dry deposition flux) were assessed. 相似文献
533.
Yoshihisa Kohno Hideyuki Matsumura Makoto Miwa Tetsushi Yonekura Keiji Aihara Chanin Umponstira Vo Thanh Le Nguyen Thuy Ngoc Phanm Hung Viet Ma Wei 《Environmental monitoring and assessment》2013,185(3):2755-2765
We developed small and mobile open top chambers (mini-OTC) measuring 0.6 m (W)?×?0.6 m (D)?×?1.2 m (H) with an air duct of 0.6 m (W)?×?0.23 m (D)?×?1.2 m (H). The air duct can be filled with activated charcoal to blow charcoal filtered air (CF) into the chamber, as opposed to non-filtered ambient air (NF). Ozone sensitive radish Raphanus sativus cv. Red Chime and rosette pakchoi Brassica campestris var. rosularis cv. ATU171 were exposed to NF and CF in mini-OTCs at different locations in East Asia. A total of 29 exposure experiments were conducted at nine locations, Shanghai, China, Ha Noi, Vietnam, Lampang, Phitsanulok and Pathumtani, Thailand, and Hiratsuka, Kisai, Abiko and Akagi, Japan. Although no significant relationships between the mean concentrations of ambient O3 during the experimental period and the growth responses were observed for either species, multiple linear regression analysis suggested a good relationship between the biomass responses in each species and the O3 concentration, temperature, and relative humidity. The cumulative daily mean O3 (ppb/day) could be indirectly predicted by NF/CF based on the dry weight ratio of biomass, mean air temperature, and relative air humidity. 相似文献
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为了能够提高电力系统运行过程中的可靠性,基于振动信号研究了电力系统变压器中出现的机械故障诊断方法。分析了BIM定位不同测点下的振动信号,利用时域频谱图对比分析了相同相、不同位置和不同相、相同位置的振动信号基频幅值。提出了基于小波包变换的振动信号故障特征提取方法,将信号特征转化为数值特征,为变压器机械故障的智能诊断提供了工具方法。最后,在传统PSO算法中引入了惯性权值,将改进后的IPSO算法与BPNN进行结合,得到了优化后的IPSO-BPNN算法模型。通过分析得知,IPSO-BPNN算法模型的收敛速度更快,具有更少的时间成本、更低的计算资源消耗、更高的准确性。 相似文献
538.
高浓度絮状颗粒污泥生物处理技术及其传质模型 总被引:1,自引:0,他引:1
从宏观角度提出了高浓度絮状颗粒污泥的传质物理模型,该模型指出:利用高分子有机药剂使形成的絮状颗粒污泥,在适当剪切条件下始终雏持”包裹-破裂-再包裹”不断循环的过程,絮状颗粒污泥内部微生物与氧气、有机物等物质的接触、吸附和捕获的几率大大提高,既增加了絮体的比表面积,又提高了其微生物的活性.从而解决了高浓度生物处理技术传质效率低的问题,并通过实验验证了该模型.图5,参16. 相似文献
539.
选择西南地区2000年、2010年、2020年3期土地利用遥感影像数据,利用土地利用动态度分析土地利用变化情况,并依据当量因子法对生态系统服务价值(ecosystem service value,ESV)开展评估.结果表明:西南地区土地利用以林地、耕地和草地为主,分别约占总面积的48%、28%、20%.人工表面、草地、... 相似文献
540.
Radon adsorption by activated charcoal collectors such as PicoRad radon detectors is known to be largely affected by temperature and relative humidity. Quantitative models are, however, still needed for accurate radon estimation in a variable environment. Here we introduce a temperature calibration formula based on the gas adsorption theory to evaluate the radon concentration in air from the average temperature, collection time, and liquid scintillation count rate. On the basis of calibration experiments done by using the 25 m3 radon chamber available at the National Institute of Radiological Sciences in Japan, we found that the radon adsorption efficiency may vary up to a factor of two for temperatures typical of indoor conditions. We expect our results to be useful for establishing standardized protocols for optimized radon assessment in dwellings and workplaces. 相似文献