Comparative study between a new nonlinear model and common linear model for analysing laboratory simulated‐forest hyperspectral data

2009 ◽  
Vol 30 (11) ◽  
pp. 2951-2962 ◽  
Author(s):  
Wenyi Fan ◽  
Baoxin Hu ◽  
John Miller ◽  
Mingze Li
Keyword(s):  
Comparative Study ◽  
Linear Model ◽  
Nonlinear Model ◽  
Hyperspectral Data

QUALITATIVE PROPERTIES OF A POPULATION DYNAMICS SYSTEM DESCRIBING PREGNANCY

2005 ◽  
Vol 15 (04) ◽  
pp. 507-554 ◽  
Author(s):  
G. FRAGNELLI ◽  
P. MARTINEZ ◽  
J. VANCOSTENOBLE
Keyword(s):  
Population Dynamics ◽  
Asymptotic Behavior ◽  
Linear Model ◽  
Nonlinear Model ◽  
Total Population ◽  
Type A ◽  
Qualitative Properties

We study a model of population dynamics describing pregnancy: our model is composed by an equation describing the evolution of the total population, and an equation describing the evolution of pregnant individuals. These equations are of course coupled: one coupling expresses that the total population varies with the number of born people, and another coupling says that the number of fecundated individuals depends on the total population. We study three models of that type: a linear model without diffusion, a nonlinear model without diffusion and a linear model with diffusion. For these three models, we study precisely the qualitative properties and the asymptotic behavior of the solutions.

scholarly journals Efficient Market Hypothesis and the RMB-Dollar Rates: A Nonlinear Modeling of the Exchange Rate

2018 ◽  
Vol 10 (2) ◽  
pp. 150
Author(s):  
Hongxing Yao ◽  
Abdul Rashid Abdul Rahaman
Keyword(s):  
Exchange Rate ◽  
Root Mean Square Error ◽  
Linear Model ◽  
Mean Square Error ◽  
Root Mean Square ◽  
Nonlinear Model ◽  
Efficient Market Hypothesis ◽  
Mean Square ◽  
Forecast Performance ◽  
The Exchange Rate

This paper uses a SETAR model to determine threshold(s) in the RMB/US$ exchange rate from 1981 to 2016 using monthly data. Also, it compares the forecast performance of the univariate nonlinear model to a univariate linear model. We further analyze the forecast performance of the SETAR model to a multivariate linear model, e.g., a Reduced-form VAR. In addition, the research assesses the claim by Boero and Marrocu (2002) that the root mean square error masks the superiority of the nonlinear models.We found five significant thresholds in the RMB/US$ exchange rate, and this result reflects five major episodes of policy reforms or structural changes in the renminbi exchange rates from the period 1981 to 2016. We also found that the univariate nonlinear model out performs both the univariate and multivariate linear models in predicting the exchange rate movements. This finding is consistent with the results in Kyei and Gyamfi (2016), Boero and Marrocu (2002), Krager and Kugler (1993), Peel and Speight (1994) and Chappell et al. (1996). Furthermore, we did not find any evidence of the root mean square error masking the superiority of the nonlinear model.

scholarly journals Mediterranean diet score and incidence of IHD: a global comparative study

2019 ◽  
Vol 22 (8) ◽  
pp. 1444-1450 ◽  
Author(s):  
Ayako Sezaki ◽  
Tomoko Imai ◽  
Keiko Miyamoto ◽  
Fumiya Kawase ◽  
Hiroshi Shimokata
Keyword(s):  
Comparative Study ◽  
Linear Model ◽  
Mediterranean Diet ◽  
General Linear Model ◽  
General Linear ◽  
Mediterranean Diet Score ◽  
Per Capita ◽  
The Mediterranean ◽  
International Comparative ◽  
Diet Score

AbstractObjectiveThe aim of the present study was to clarify the global relationship between Mediterranean diet score (MDS) and the incidence of IHD by country using international statistics.DesignThe incidence of IHD by country was derived from the Global Burden of Disease (GBD) database. Average supplies of food (g/d per capita) and energy (kcal/d per capita) by country, excluding loss between production and household, were obtained from the FAOSTAT database. MDS was evaluated based on the total score of nine food items that characterize the Mediterranean diet. The association between MDS and the incidence of IHD was examined in countries with a population of 1 million or greater using a general linear model controlled for socio-economic and lifestyle variables.SettingPopulation data from global international databases.ParticipantsOne hundred and thirty-two countries with a population of over 1 million.ResultsMDS was inversely correlated with obesity rate, ageing rate, years of education and IHD incidence; however, no associations were found with gross domestic product, life expectancy, smoking rate, energy supply or health expenditure. In the general linear model of IHD incidence by MDS controlled for socio-economic and lifestyle variables, the β of the MDS was –26·4 (se 8·6; P<0·01).ConclusionsThe results of this global international comparative study confirmed that the Mediterranean diet is inversely associated with the incidence of IHD.

A comparative study of water wall model with a linear model and a neural network model

2014 ◽  
Vol 47 (3) ◽  
pp. 1446-1451
Author(s):  
Un-Chul Moon ◽  
Jaewoo Lim ◽  
Geon Go ◽  
Kwang. Y. Lee
Keyword(s):  
Neural Network ◽  
Comparative Study ◽  
Linear Model ◽  
Network Model ◽  
Neural Network Model ◽  
Wall Model ◽  
Water Wall

The Modeling of Electrohydraulic Proportional Valves

2011 ◽  
Vol 134 (2) ◽  
Author(s):  
Davide Cristofori ◽  
Andrea Vacca
Keyword(s):  
Steady State ◽  
Linear Model ◽  
Nonlinear Model ◽  
3D Model ◽  
Fluid Dynamic ◽  
Body Motion ◽  
General Nature ◽  
Relief Valve ◽  
Real Component ◽  
Electromagnetic Model

The present work describes the modeling of a proportional relief valve actuated by an electromagnet. Two models were developed and compared each other: a detailed nonlinear model and its linearized version. The modeling approach presented has a general nature and can be applied to various types of electrohydraulic proportional valves (EHPV). The comparison between nonlinear and linear model results shows the limits of the linear approximation to study the real component. Substantially, the nonlinear model is composed by three submodels: the fluid-dynamic model (for the evaluation of the main flow features), the mechanical model (which solves the mobile body motion), and the electromagnetic model (which evaluates the magnetic forces and the electric transient). All submodels are based on a lumped parameter (LP) approach and they implement a specific set of nonlinear equations. However, to carefully model the main electromagnetic phenomena that characterize the proportional electromagnet behavior (including: magnetic losses, fringing effects, and magnetic saturation), a finite element analysis (FEA) 3D model was developed by the authors. The LP electromagnetic model is based on a particular use of the FEA 3D model steady state results. A series of transient simulations were performed through the FEA 3D model in order to quantify the effect of the eddy currents and to determine a second order transfer function used in the linear model to describe the electromagnet dynamics. The remaining parts of the linear model are obtained by linearizing the nonlinear model equations. The FEA 3D model was experimentally validated in steady-state conditions, while the results of the overall model of the valve were verified in both steady-state and dynamic conditions.

scholarly journals Flux Reflection Model of the Ferroresonant Circuit

2009 ◽  
Vol 2009 ◽  
pp. 1-13 ◽  
Author(s):  
Kruno Miličević ◽  
Ivan Flegar ◽  
Denis Pelin
Keyword(s):  
Physical Model ◽  
Linear Model ◽  
Nonlinear Model ◽  
Steady States ◽  
Reflection Model ◽  
Proposed Model ◽  
Simulation Results ◽  
Ferroresonant Circuit ◽  
Nonlinear Coil

The paper presents a linear model of ferroresonant circuit with flux reflection. The proposed model—flux reflection model—derives from observations of typical flux waveforms of nonlinear coil during ferroresonant steady states. Simulation results of the flux reflection model are compared with simulation results of the usual nonlinear model as well as with measurements carried out on the physical model of the ferroresonant circuit. The flux reflection model enables a novel comprehension of the ferroresonant circuit behavior and simplifies the modeling of the nonlinear coil in the ferroresonant circuit.

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