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Linah Mohamed Ben Calderhead Maurizio Filippone Mike Christie Mark Girolami 《Computational Geosciences》2012,16(2):423-436
This paper presents the application of a population Markov Chain Monte Carlo (MCMC) technique to generate history-matched
models. The technique has been developed and successfully adopted in challenging domains such as computational biology but
has not yet seen application in reservoir modelling. In population MCMC, multiple Markov chains are run on a set of response
surfaces that form a bridge from the prior to posterior. These response surfaces are formed from the product of the prior
with the likelihood raised to a varying power less than one. The chains exchange positions, with the probability of a swap
being governed by a standard Metropolis accept/reject step, which allows for large steps to be taken with high probability.
We show results of Population MCMC on the IC Fault Model—a simple three-parameter model that is known to have a highly irregular
misfit surface and hence be difficult to match. Our results show that population MCMC is able to generate samples from the
complex, multi-modal posterior probability distribution of the IC Fault model very effectively. By comparison, previous results
from stochastic sampling algorithms often focus on only part of the region of high posterior probability depending on algorithm
settings and starting points. 相似文献
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Majdi Al-Mahasneh Mohamad Al-Widyan Hussein Ababneh Taha Rababah Khalil Ereifej 《Natural Resources Research》2008,17(1):13-20
Grain dust is a by-product produced in large quantities from grain storage and milling facilities but as of yet is treated
as waste locally and regionally. Based on the conviction that material properties determination is a necessary first step
for the efficient handling, processing, and use of materials, this work was initiated with the purpose of characterizing grain
dust in terms of its physicochemical and thermal properties.
Grain dust as a special waste material is a complex, dry, grey powder, composed mainly of grain chips, soil, whole wheat and
barley seeds, and straw. The material was found to have a bulk density of 362 kg/m3, specific heat, thermal conductivity, and gross calorific value were 1540 J/kg K, 0.27 W/m K, and 4120 kJ/kg, respectively.
Nutritional composition showed low concentrations of protein, and ether extract, and high concentrations of carbohydrates,
ash, and crude fiber. Mineral analysis showed that Ca, Fe, and K were available in significant amounts ranging from 30 to
135 ppm.
The as-received material is dry enough to be stored very safely and burned for energy production in either its loose form
or as pellets. Moreover, adjustments to the ash content and C:N ratio of the material deems it a promising candidate as an
animal feed and as a substrate for composting and biogasification. 相似文献
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Shifts in aquatic and terrestrial vegetation associations and hydrology during the past > 3100 yr are indicated by the pollen and sediment sequences in a core retrieved from the Azraq wetland, Jordan. The pollen sequence provides evidence for a relatively stable wetland during the period of study until ca. AD 1400 when the wetland apparently declined as desert shrubland expanded. Springs continually supplied fresh water that maintained the shallow pools and marsh. In periods of increased winter precipitation, runoff from the surrounding wadis may have inundated the wetland and deposited silts and clays. During dryer episodes the influx of winter storm water would have been much less but the springs would have still provided water to the wetland and deposited peat. This is shown by the sequences of clay, silty and sandy clay loam, and peat in the core. 相似文献
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