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Model Captures (model + capture)

Distribution by Scientific Domains

Business, Economics, Finance and Accounting	50%

Selected Abstracts

A note on estimating urban roof runoff with a forest evaporation model

HYDROLOGICAL PROCESSES, Issue 8 2008
J. H. C. Gash
Abstract A model developed for estimating the evaporation of rainfall intercepted by forest canopies is applied to estimate measurements of the average runoff from the roofs of six houses made in a previous study of hydrological processes in an urban environment. The model is applied using values of the mean rates of wet canopy evaporation and rainfall derived previously for forests and an estimate of the roof storage capacity derived from the data collected in the previous study. Although the model prediction is sensitive to the value of storage capacity, close correlation between the modelled and measured runoff indicates that the model captures the essential processes. It is concluded that the process of evaporation from an urban roof is sufficiently similar to that from a forest canopy for forest evaporation models to be used to give a useful estimate of urban roof runoff. Copyright © 2007 John Wiley & Sons, Ltd. [source]

External Constraints on Monetary Policy and the Financial Accelerator

JOURNAL OF MONEY, CREDIT AND BANKING, Issue 2-3 2007
MARK GERTLER
financial crises; exchange rate policy We develop a small open economy macroeconomic model where financial conditions influence aggregate behavior. Our goal is to explore the connection between the exchange rate regime and financial distress. We first show that a calibrated version of the model captures well the behavior of the Korean economy during its financial crisis period of 1997,98. In particular, the model accounts for the sharp increase in lending rates and the large drop in output, employment, investment, and measured productivity. The financial market frictions play an important role, further, explaining roughly half the decline in overall economic activity. We then perform some counterfactual exercises to illustrate how the fixed exchange rate regime likely exacerbated the crisis by tying the hands of monetary policy. [source]

Two-scale continuum model for simulation of wormholes in carbonate acidization

AICHE JOURNAL, Issue 12 2005
Mohan K. R. Panga
Abstract A two-scale continuum model is developed to describe transport and reaction mechanisms in reactive dissolution of a porous medium, and used to study wormhole formation during acid stimulation of carbonate cores. The model accounts for pore level physics by coupling local pore-scale phenomena to macroscopic variables (Darcy velocity, pressure and reactant cup-mixing concentration) through structure-property relationships (permeability-porosity, average pore size-porosity, and so on), and the dependence of mass transfer and dispersion coefficients on evolving pore scale variables (average pore size and local Reynolds and Schmidt numbers). The gradients in concentration at the pore level caused by flow, species diffusion and chemical reaction are described using two concentration variables and a local mass-transfer coefficient. Numerical simulations of the model on a two-dimensional (2-D) domain show that the model captures the different types of dissolution patterns observed in the experiments. A qualitative criterion for wormhole formation is developed and it is given by , , O(1), where , = . Here, keff is the effective volumetric dissolution rate constant, DeT is the transverse dispersion coefficient, and uo is the injection velocity. The model is used to examine the influence of the level of dispersion, the heterogeneities present in the core, reaction kinetics and mass transfer on wormhole formation. The model predictions are favorably compared to laboratory data. © 2005 American Institute of Chemical Engineers AIChE J, 2005 [source]

Inter-temporal and Inter-industry Effects of Population Ageing: A General Equilibrium Assessment for Canada

LABOUR, Issue 4 2009
Nabil Annabi
In addition to the impact of slower labour force growth, the model captures the shift in sectoral composition of final demand of older individuals. The simulation results indicate that the growth in real GDP per capita could decline by nearly one percentage point between 2006 and 2050. The results also suggest that the equilibrium unemployment rate is likely to decline by more than two percentage points in the long run. However, the impact varies significantly at the occupational level. [source]

Gas-solid Two-phase Mixtures Flowing Upward through a Confined Packed Bed,

PARTICLE & PARTICLE SYSTEMS CHARACTERIZATION, Issue 3-4 2006
Yurong He
Abstract This paper deals with flows of a gas-solid two-phase mixture through a confined packed bed. Both experimental work and numerical modelling are performed on the behaviour of suspended particles within the packed bed. The experimental work is carried out with a non-intrusive Positron Emission Particle Tracking (PEPT) technique, which tracks particle motion at the single particle level for a prolonged period thus allows both the microscopic and macroscopic solids behaviour to be analysed under the steady-state conditions. A continuous based model is used to simulate the flow behaviour. The model uses a newly proposed porosity model and treats the suspended and packed particles as a binary mixture with the packed particles being at zero velocity. The results show that the model captures the main features of solids behaviour in terms of the radial distributions of the suspended particle concentration and the axial solids velocity. Both the experiments and modelling suggest that the wall effect on the motion of suspended particles be limited to a small region close to the wall (,0.5,1 packed particle diameter). However, deviations exist between the model predictions and experiments; more work is therefore proposed to improve the interaction terms in the model between the suspended and packed particles. [source]

Out-of-sample Hedge Performances for Risk Management in China Commodity Futures Markets,

ASIAN ECONOMIC JOURNAL, Issue 3 2009
Sang-Kuck Chung
C13; C32; G13 We consider a new time-series model that describes long memory and asymmetries simultaneously under the dynamic conditional correlation specification, and that can be used to assess an extensive evaluation of out-of-sample hedging performances using aluminum and fuel oil futures markets traded on the Shanghai Futures Exchange. Upon fitting it to the spot and futures returns of aluminum and fuel oil markets, it is found that a parsimonious version of the model captures the salient features of the data rather well. The empirical results suggest that separating the effects of positive and negative basis on the market volatility, and the correlation between two markets as well as jointly incorporating the long memory effect of the basis on market returns not only provides better descriptions of the dynamic behaviors of commodity prices, but also plays a statistically significant role in determining dynamic hedging strategies. [source]