scholarly journals Special Issue on ‘Nonlinear Modeling, Analysis, and Simulation for Earthquake Engineering’Earthquake Engineering and Structural Dynamics (EQE)

2007 ◽  
Vol 36 (15) ◽  
pp. i-ii
Author(s):  
Gregory L. Fenves ◽  
Anil K. Chopra
Keyword(s):  
Structural Dynamics ◽  
Nonlinear Modeling ◽  
Special Issue ◽  
Modeling Analysis

scholarly journals Editorial

2018 ◽  
Vol 2 (3) ◽  
pp. 1
Author(s):  
Raimundo Delgado
Keyword(s):  
Structural Dynamics ◽  
Civil Engineering ◽  
Seismic Analysis ◽  
Doctoral Program ◽  
Seismic Loading ◽  
Extended Version ◽  
Special Issue ◽  
Training Process ◽  
Interesting Paper ◽  
Selection Of

This special issue of U. Porto Journal of Engineering includes a selection of papers that were presented at the Symposium on Civil Engineering held during the 1st Doctoral Congress in Engineering (DCE 2015). A set of very interesting papers were presented at that session and their authors were invited to submit an extended version of their papers for inclusion in a special issue of this journal. After the reviewing process five papers have been selected covering mainly two different topics: transport infrastructures and structural dynamics and seismic analysis. The first topic is raised in an interesting paper entitled Freeway geometric design comparison between Mexico and Portugal. The second is brought up in four papers which cover very important and updated subjects, such as structural analysis, seismic loading characterization and losses’ estimation. All papers selected include original contributions and I´m strongly convinced that they will be a very interesting tool for the study of the referred subjects. Finally, I would like to congratulate all authors of the published papers and emphasize that the main objectives of this congress have been achieved, namely in what concerns the training process of the students enrolled in the Doctoral Program in Civil Engineering at FEUP.

A SIMPLE GEOMETRICAL STRUCTURE UNDERLYING SPEECH SIGNALS OF THE JAPANESE VOWEL /a/

1996 ◽  
Vol 06 (01) ◽  
pp. 149-160 ◽  
Author(s):  
ISAO TOKUDA ◽  
RYUJI TOKUNAGA ◽  
KAZUYUKI AIHARA
Keyword(s):  
Cross Sections ◽  
Initial Conditions ◽  
Nonlinear Modeling ◽  
Three Dimensional ◽  
Principal Component ◽  
Coordinate Space ◽  
Speech Signals ◽  
Vowel Sound ◽  
Modeling Analysis ◽  
Sensitive Dependence

We provide several pieces of evidence for possible chaotic dynamics in the irregular behavior of normal speech signals of the Japanese vowel /a/. First, principal component analysis demonstrates that a simple geometric structure underlying the complex speech signal is well reconstructed in a three-dimensional delay-coordinate space. Observations of the reconstructed speech trajectory at multiple cross sections also display speech dynamics with stretching, folding and compressing. Second, Lyapunov spectrum analysis indicates sensitive dependence on initial conditions with a positive Lyapunov exponent for the speech signals of several different speakers. Third, nonlinear modeling analysis with an artificial neural network shows that the nonlinear dynamics of the vowel sound is well reproduced by a deterministic dynamical model.

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