Automatic model selection and parameter estimation based on different features. Introduction for first time in structural dynamics of the Approximate Dynamics of the standard model pdf computation for model selection. ABC is a likelihood-free method typically used when the likelihood function is either intractable or cannot be approached in a closed form. To circumvent the evaluation of the likelihood function, simulation from a forward model is at the core of the ABC algorithm.
The algorithm offers the possibility to use different metrics and summary statistics representative of the data to carry out Bayesian inference. The efficacy of the algorithm in structural dynamics is demonstrated through three different illustrative examples of nonlinear system identification: cubic and cubic-quintic models, the Bouc-Wen model and the Duffing oscillator. The obtained results suggest that ABC is a promising alternative to deal with model selection and parameter estimation issues, specifically for systems with complex behaviours. A model in which homebuyers make a modest approximation leads house prices to display three features present in the data but usually missing from rational models: momentum at one-year horizons, mean reversion at five-year horizons, and excess longer-term volatility relative to fundamentals. Approximating buyers assume that past prices reflect only contemporaneous demand, just like professional economists who use trends in housing prices to infer trends in housing demand. Consistent with survey evidence, this approximation leads buyers to expect increases in the market value of their homes after recent house price increases.
Check if you have access through your login credentials or your institution. We thank Nicholas Barberis, Kent Daniel, Ian Dew-Becker, Fernando Ferreira, Adam Guren, David Levine, Monika Piazzesi, Giacomo Ponzetto, Richard Stanton, Stijn Van Nieuwerburgh, Eric Zwick, seminar participants at Northwestern University Kellogg School of Management, Universidad Pompeu Fabra Research Center for International Economics, European University Institute, Society for Economic Dynamics, Stanford Institute for Theoretical Economics, and the National Bureau of Economic Research Summer Institute, and an anonymous referee for helpful comments. Glaeser thanks the Taubman Center for State and Local Government at Harvard University, and Charles G. Nathanson thanks the Guthrie Center for Real Estate Research for financial support.
The applications are mostly in video games and films. The scope of soft body dynamics is quite broad, including simulation of soft organic materials such as muscle, fat, hair and vegetation, as well as other deformable materials such as clothing and fabric. Softbody objects react to forces and are able to collide with other 3D objects. Two nodes as mass points connected by a parallel circuit of a spring and a damper. Additional springs between nodes can be added, or the force law of the springs modified, to achieve desired effects. To approximate finite element simulation, shape matching can be applied to three dimensional lattices and multiple shape matching constraints blended.