TRANSITIONAL DYNAMICS AND THRESHOLDS IN ROMER'S ENDOGENOUS TECHNOLOGICAL CHANGE MODEL

2002 ◽  
Vol 6 (3) ◽  
pp. 442-456 ◽  
Author(s):  
Pedro Garcia-Castrillo ◽  
Marcos Sanso
Keyword(s):  
Steady State ◽  
Technological Change ◽  
Dynamic Behavior ◽  
Physical Capital ◽  
Change Model ◽  
Dimensional Manifold ◽  
Transitional Dynamics ◽  
One Dimensional ◽  
Endogenous Technological Change ◽  
Relevant Variables

We obtain the transitional dynamics of the decentralized economy described by P.M. Romer and characterize the dynamic behavior of the most relevant variables. We determine the existence of a stable one-dimensional manifold containing a steady state with innovation, unique in ratios, and also find a threshold in the accumulation of physical capital below which the economy is not innovating. Finally, using simulations, we assess the significance of this threshold and analyze the influence that technological and utility parameters have on it.

scholarly journals Investment in time preference and long-run distribution

2019 ◽  
Vol 71 (2) ◽  
pp. 171-190
Author(s):  
Takashi Hayashi
Keyword(s):  
Steady State ◽  
Time Preference ◽  
Dimensional Space ◽  
Physical Capital ◽  
Two Dimensional ◽  
Lower Side ◽  
One Dimensional ◽  
Dynamic General Equilibrium Model ◽  
Long Run ◽  
Opt Out

AbstractThis paper presents a simple dynamic general equilibrium model in which each household can make a costly investment in patience capital at each time. We show that the interior long-run steady state is unstable, in the sense that per household, there is a one-dimensional curve lying in the two-dimensional space of its patience capital and physical capital amounts, and convergence happens only when its initial pair falls exactly on the curve. Households with the initial vectors falling in the upper side of the curve invest more in patience capital, which leads themselves to save more, and hence, the consumption level grows in the long run. Households with the initial vectors falling in the lower side opt out from investing in patience capital, leading to a decay of patience level, which leads themselves to save less and hence they perish in the long run. We also show a possibility that there is an expanding swing between the two classes.

Selection of one-dimensional sedimentation: models for on-line use

1995 ◽  
Vol 31 (2) ◽  
pp. 193-204 ◽  
Author(s):  
Koen Grijspeerdt ◽  
Peter Vanrolleghem ◽  
Willy Verstraete
Keyword(s):  
Steady State ◽  
Selection Criteria ◽  
Data Sets ◽  
Concentration Profiles ◽  
A Posteriori ◽  
One Dimensional ◽  
On Line ◽  
Dynamic Concentration ◽  
Selection Of ◽  
Modelling Task

A comparative study of several recently proposed one-dimensional sedimentation models has been made. This has been achieved by fitting these models to steady-state and dynamic concentration profiles obtained in a down-scaled secondary decanter. The models were evaluated with several a posteriori model selection criteria. Since the purpose of the modelling task is to do on-line simulations, the calculation time was used as one of the selection criteria. Finally, the practical identifiability of the models for the available data sets was also investigated. It could be concluded that the model of Takács et al. (1991) gave the most reliable results.

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