Transient implicit wave propagation dynamics with the method of finite spheres

2016 ◽  
Vol 173 ◽  
pp. 50-60 ◽  
Author(s):  
Ki-Tae Kim ◽  
Klaus-Jürgen Bathe
Keyword(s):  
Wave Propagation ◽  
Propagation Dynamics ◽  
Finite Spheres

Transient implicit wave propagation dynamics with overlapping finite elements

2018 ◽  
Vol 199 ◽  
pp. 18-33 ◽  
Author(s):  
Ki-Tae Kim ◽  
Lingbo Zhang ◽  
Klaus-Jürgen Bathe
Keyword(s):  
Wave Propagation ◽  
Finite Elements ◽  
Propagation Dynamics

Blind Identification of 2-Channel IIR Wave Propagation Systems for Central Cardiovascular Monitoring

2008 ◽  
Author(s):  
Jin-Oh Hahn ◽  
Andrew T. Reisner ◽  
H. Harry Asada
Keyword(s):  
Blood Pressure ◽  
Wave Propagation ◽  
Infinite Impulse Response ◽  
Identification Algorithm ◽  
Blind Identification ◽  
Pressure Measurements ◽  
Cardiovascular Monitoring ◽  
Channel Dynamics ◽  
Identification Approach ◽  
Propagation Dynamics

This paper presents a new approach to blind identification of a class of 2-channel infinite impulse response (IIR) systems describing the wave propagation dynamics. For these systems, this paper derives a blind identifiability condition and develops a blind identification algorithm, which is capable of uniquely determining both the numerator and denominator polynomials of the channel dynamics. The efficacy of the method is illustrated by a 2-sensor central cardiovascular monitoring application as an example, where the cardiovascular blood pressure wave propagation dynamics is identified and the aortic signals are reconstructed from blood pressure measurements at two distinct extremity locations. Experimental results using a swine subject illustrate how the new blind identification approach effectively identifies cardiovascular dynamics and reconstructs the aortic blood pressure and flow signals very accurately from two distinct peripheral blood pressure measurements under diverse physiologic conditions.

Blind Identification of Two-Channel IIR Systems With Application to Central Cardiovascular Monitoring

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
Jin-Oh Hahn ◽  
Andrew T. Reisner ◽  
H. Harry Asada
Keyword(s):  
Blood Pressure ◽  
Wave Propagation ◽  
Input Signal ◽  
Infinite Impulse Response ◽  
Blind Identification ◽  
Cardiovascular Monitoring ◽  
Channel Dynamics ◽  
Aortic Blood ◽  
Aortic Blood Pressure ◽  
Propagation Dynamics

This paper presents a new approach to blind identification of a class of two-channel infinite impulse response (IIR) systems with applicability to clinical cardiovascular monitoring. Specifically, this paper deals with a class of two-channel IIR systems describing wave propagation dynamics. For this class of systems, this paper first derives a blind identifiability condition and develops a blind identification algorithm, which is able to determine both the numerator and denominator polynomials of the channel dynamics uniquely. This paper also develops a new input signal deconvolution algorithm that can reconstruct the input signal from the identified two-channel dynamics and the associated two-channel measurements. These methods are applied to identify the pressure wave propagation dynamics in the cardiovascular system and reconstruct the aortic blood pressure and flow signals from blood pressure measurements taken at two distinct extremity locations. Persistent excitation, model identifiability, and asymptotic variance are analyzed to quantify the method’s validity, accuracy, and reliability without employing direct measurement of the aortic blood pressure and flow signals. The experimental results based on 83 data segments obtained from a swine subject illustrate how the cardiovascular dynamics can be identified accurately and reliably, and the aortic blood pressure and flow signals can be stably reconstructed from two distinct peripheral blood pressure signals under diverse physiologic conditions.

Transfer Entropy Provides Insight into Wave Propagation Dynamics: A Preliminary Study

2018 ◽  
Vol 27 ◽  
pp. S199
Author(s):  
D. Dharmaprani ◽  
L. Dykes ◽  
A. McGavigan ◽  
P. Kuklik ◽  
A. Ganesan
Keyword(s):  
Wave Propagation ◽  
Transfer Entropy ◽  
Preliminary Study ◽  
Propagation Dynamics ◽  
Insight Into

Experimental Study of Wave Propagation Dynamics of Multicomponent Distillation Columns

1999 ◽  
Vol 38 (10) ◽  
pp. 3588-3605 ◽  
Author(s):  
Jack Ting ◽  
Friedrich G. Helfferich ◽  
Yng-Long Hwang ◽  
Glenn K. Graham ◽  
George E. Keller
Keyword(s):  
Experimental Study ◽  
Wave Propagation ◽  
Distillation Columns ◽  
Multicomponent Distillation ◽  
Propagation Dynamics

The method of finite spheres for wave propagation problems

2014 ◽  
Vol 142 ◽  
pp. 1-14 ◽  
Author(s):  
Seounghyun Ham ◽  
Benjamin Lai ◽  
Klaus-Jürgen Bathe
Keyword(s):  
Wave Propagation ◽  
Finite Spheres

scholarly journals The method of finite spheres in acoustic wave propagation through nonhomogeneous media: Inf-sup stability conditions

2020 ◽  
Vol 42 (3) ◽  
pp. 209-237
Author(s):  
Williams L. Nicomedes ◽  
Klaus-Jürgen Bathe ◽  
Fernando J. S. Moreira ◽  
Renato C. Mesquita
Keyword(s):  
Wave Propagation ◽  
Acoustic Wave ◽  
Acoustic Wave Propagation ◽  
Nonhomogeneous Media ◽  
Finite Dimensional ◽  
Pressure Fields ◽  
Time Harmonic ◽  
The Stability ◽  
Finite Spheres ◽  
Well Posed

When the method of finite spheres is used for the solution of time-harmonic acoustic wave propagation problems in nonhomogeneous media, a mixed (or saddle-point) formulation is obtained in which the unknowns are the pressure fields and the Lagrange multiplier fields defined at the interfaces between the regions with distinct material properties. Then certain inf-sup conditions must be satisfied by the discretized spaces in order for the finite-dimensional problems to be well-posed. We discuss in this paper the analysis and use of these conditions. Since the conditions  involve norms of functionals in fractional Sobolev spaces, we derive ‘stronger’ conditions that are simpler in form. These new conditions pave the way for the inf-sup testing, a tool for assessing the stability of the discretized problems.

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