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51.
为挖掘飞行数据中的高危险性操作模式,采用k-SC时间序列聚类算法,并基于K-W检验分析聚类结果与不安全事件之间的关系。以特定条件下某机队着陆阶段的驾驶杆操作数据和长着陆事件为例进行模型验证。结果表明:机队有5类不同的驾驶杆操作模式;不同操作模式的着陆平飘距离分布具有显著性差异,且长着陆的危险性最高可达68.18%。研究结果可为提升航空公司飞行员操作能力、分析飞行员操作特性及其他不安全事件(如重着陆、擦机尾等)提供理论参考。 相似文献
52.
This paper analyzes the three main fundamental issues in the design of China’s ETS pilots,including allowance allocation,price mechanism and state-owned key enterprises,and proposed suggested solutions.For the issue of allowance allocation,we suggest that the gradual hybrid mode could be applied at the beginning,which starts with mainly free allocation and then increases auction ratio gradually.And grandfathering is a suitable method of free allocation.For the issue of price mechanism,we suggest a price floating zone with open market operation to reduce the uncertainty of prices.For the issue of state-owned key enterprises,we suggest a good coordination with SASAC,defining the state-owned property right and supervision right when state-owned key enterprises are involved into the carbon market,and the local government can set rules of allocation and transaction to limit their potential market power. 相似文献
53.
结合2008年11月18~25日期间珠三角地区的二次有机气溶胶(SOA)外场观测数据,验证区域空气质量模式WRF/Chem(weather research and forecasting model with chemistry)中两种SOA化学机制——VBS(volatile basis set)和SORGAM(secondary organic aerosol model)对珠三角SOA的模拟效果.VBS机制考虑了更为广泛的SOA前体物和化学老化过程,SOA模拟值更接近观测值,能合理反映SOA观测值的逐天变化趋势,与观测值的平均绝对偏差和相关性分别是-4.88μg·m-3和0.91,而SORGAM机制的分别为-5.32μg·m-3和0.18.利用VBS机制模拟区域内SOA的时空分布,结果显示SOA浓度具有显著的昼夜变化特征,浓度峰值出现在中午时段.受到输送和臭氧区域分布的影响,各城市SOA浓度差异显著,下风向的城市(如中山、珠海、江门)SOA浓度较高. 相似文献
54.
为探究单一飞行员驾驶模式(SPO)下飞行员的脑力负荷水平,设计并实施模拟单人驾驶情境中的非正常任务场景处置实验。首先,基于准5级模拟驾驶舱,设计飞行任务场景;其次,招募20名航线飞行员被试,开展模拟飞行实验,记录被试的生理数据心率变异性指标及眼动数据;最后,结合客观生理数据以及主观量表进行脑力负荷分析,记录单发失效故障处置时间并进行任务绩效分析。研究结果表明:与双人制机组相比,单人驾驶情境中飞行员的脑力负荷增幅并不显著,处于可接受范围;单人制驾驶舱的任务设计及智能辅助系统使用对于降低飞行员工作负荷,提升飞行绩效至关重要。研究结果可为单一飞行员驾驶模式实施提供理论支持,并为未来单人制驾驶舱及机载自动化系统设计提供指标参考。 相似文献
55.
Gotzon Gangoiti Milln M. Milln Rosa Salvador Enrique Mantilla 《Atmospheric environment (Oxford, England : 1994)》2001,35(36):2163
During the warm season (March–September), high ozone concentrations have been reported at the coastal and mountain monitoring stations of the eastern Iberia coast (Millán et al., J. Geophys. Res. 102 (D7) 8811, J. Appl. Meteorol. 4 (2000) 487). The vegetation protection threshold of current Directive 92/72/EEC and the World Health Organisation guideline for the protection of crops and semi-natural vegetation are systematically exceeded during the whole period. The main objective of the present study is to search for the origin of these chronic pollution levels: to search for the reason(s) for such high O3 concentrations during such a long period. A mesoscale model is used to reproduce the diurnal cycle of winds and stability/layering over the Western Mediterranean Basin (WMB), at a sufficient space/temporal resolution, under a typical recursive synoptic condition during the warm season: data from the flight tracks of the European Project—Regional Cycles of Air Pollution in the West-Central Mediterranean Area—are used to substantiate the model results. Times of residence and the final distribution of pollutants entering the WMB are estimated using single-particle Lagrangian trajectories and a multiple-particle dispersion model. Our results show that the marine boundary layer and the lower troposphere in the region between the Balearic Islands and eastern Iberia are subject to a flow regime that tends to accumulate pollutants within large circulations, covering the entire western basin. We have also shown a diurnal pulsation of the Tramontana/Mistral wind regime, which can transport new pollutants into the area (background concentrations of 50–65 ppb of O3 of continental European origin) that are added to local emissions and re-circulated within the coastal breezes at eastern Iberia for periods of more than five days. Local emissions and wind configuration contribute to increase the O3 concentrations up to 100 ppb and even more. 相似文献
56.
An optimized code for the near real-time retrieval of line of sight, temperature and volume-mixing ratio profiles of five key species (O3, H2O, HNO3, CH4 and N2O) from infrared limb spectra recorded by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) experiment on board the ENVISAT-1 satellite was developed as part of an ESA-supported study. In this code line of sight and temperature are retrieved simultaneously among themselves, but sequentially with respect to the volume-mixing ratio of the five key species. The sequential retrieval leaves unaccounted the mapping of line of sight and temperature errors in the retrieved volume-mixing ratio of the constituents. This paper illustrates an algorithm that provides the a-posteriori evaluation of temperature and line-of-sight-induced error on the retrieved volume-mixing ratio of the MIPAS key species. It is shown that in most cases temperature and line-of-sight-induced error provides a significant contribution to the total volume-mixing ratio error. The variability of this error as a function of latitude, season and atmospheric model is also analyzed. 相似文献
57.
58.
碳排放权交易已成为我国实施以市场为基础的重要环境规制之一,但此交易市场建设能否诱发我国低碳技术创新的有关研究仍然不足。以我国七个碳排放权交易试点为研究对象,采用合成控制法进行准自然实验,选取2004—2016年全国282个城市的面板数据,评估碳排放权交易试点政策对低碳技术创新的诱发效果,并使用排列检验法进行有效性检验;进而,定量分析碳排放权交易试点正式运行后对低碳技术创新的影响因素,探索七个试点效果差异的成因。研究发现:①碳排放权交易试点政策整体上诱发了试点地区的低碳技术创新活动。②各试点的政策效果存在一定差异,除重庆外的六个试点对政策响应较为迅速,其中北京、上海的诱发效果最显著,天津、广东、深圳和湖北次之,而重庆试点未能对政策作出充分的响应。③碳排放权交易对低碳技术创新作用中的政策"信号-预期"机制在我国首次得到验证,该机制在除重庆外的试点地区都得到了较好的构建。④碳排放权交易市场建设与区域产业结构升级产生了良好的协同作用,促进低碳技术创新,但其未能与外商直接投资形成相同作用;除重庆外,碳排放权交易这一市场型环境规制与控制型环境规制也呈现出协同作用。据此,应积极推进全国性碳排放权交易市场建设,以发挥其对低碳技术创新的诱发作用;但在统一市场建设过程中应重视地区差异,分步骤稳步推进;还应注重加强政府政策信号管理,引导企业开展低碳技术创新活动。 相似文献
59.
P. Steven Porter Robert C. Ward 《Journal of the American Water Resources Association》1991,27(4):687-700
ABSTRACT: The statistical analysis of data which have trace level measurements has traditionally been a two-step process in which data are first censored using criteria based on measurement precision, and then analyzed with statistical methods for censored data. The process might be more informative if data were left uncensored. In this paper, information loss attributable to censoring and measurement noise are assessed by comparing the sample mean and median of uncensored measurements with a log regression mean and median based on censored data. Measurements are derived from lognormal parent distributions which have random variability characteristic of trace level measurement. The relative performance of estimators used with error-free samples and with samples having measurement noise can be explained by differences between the probability distributions of parents and measurements. Measurement introduces bias and dispersion and transforms lognormal parent distributions toward greater symmetry. Estimates using uncensored data are less biased and more accurate than the log regression mean and median when censoring exceeds about 50 percent, and are not much worse at any fraction censored. For data with many (80 percent) results below the limit of detection, bias may be quite severe. 相似文献
60.
本文通过选定对内蒙古自治区农村牧区具有典型代表性的试验对象 ,全方位开展全民性环保意识的普及教育 ,已在试验区内收到显著的效果 ,从而对进行农村牧区居民环境教育的方式方法进行了有益的探索 ,对全国少数民族、边远地区环境教育工作也具有示范效益 相似文献