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1.
M. Rapone M. V. Prati M. A. Costagliola L. Della Ragione G. Meccariello 《Environmental Modeling and Assessment》2008,13(3):383-392
This paper presents emission factors of a class of passenger cars obtained by applying a statistical model developed to evaluate
average emission factors based on driving cycle emission measurements. A multivariate regression method based on principal
components, namely, the partial least squares (PLS) method, is applied to calculate the model. The method was applied to emission
data from a sample of petrol Euro III 1,200- to 1,400-cc passenger cars taken from the ARTEMIS database. A vehicle effect
analysis showed that vehicle effect is considerable, in some cases comparable to or greater than the driving cycle effect.
Determination of emission factors is obviously affected by these aspects. Thus, the CO2 PLS model fit results are good, CO,
HC and NOX more or less sufficient. PLS-predicted quantities were compared with corresponding quantities estimated by a multiple
regression model (GLM) based on a quadratic polynomial equation of sub-cycle overall mean speed. GLM goodness of fit was poorer
than PLS ones. A validation effort of models is in progress, which is considering the ARTEMIS database extended with tests
performed within other national or international projects. In this way, an extended population of combinations of vehicles
and driving cycles will provide a better calculation of models and emission factors. 相似文献
2.
Christian Damgaard Vibeke Simonsen Juliet L. Osborne 《Environmental Modeling and Assessment》2008,13(4):483-490
Pollen-mediated gene flow between red clover fields by bumblebees is predicted by estimating or simulating the parameters
in a gene flow model for insect-pollinated crops. Generally, the predicted level of gene flow was found to depend on the visiting
bee species and the spatial arrangement of the red clover fields. When the fields are close to each other, the gene flow depends
mainly on the typical foraging distance of the visiting bee species, but when the fields are far apart, the gene flow between
red clover fields is more sensitive to the distances between red clover fields than to the actual bumblebee species that pollinates
the fields. Using the suggested methodology, the gene flow may be predicted in different agricultural scenarios. For example,
if the gene flow between red clover fields is mediated by Bombus terrestris and the red clover fields that were assumed to be quadrates with sides of 100 m are separated by 200 m, then the median gene
flow is predicted to be 0.17%. 相似文献