23
L. Costa, E. Classe, L. Asth, L. Abreu, D. Knupp and L. Stutz,
“Estimation of Spatially Dependent Coecients in Heterogeneous Media in Diusive Heat Transfer Problems”,
Latin-American Journal of Computing (LAJC), vol. 11, no. 2, 2024.
Estimation of Spatially
Dependent Coecients
in Heterogeneous Media
in Diusive Heat Transfer
Problems
ARTICLE HISTORY
Received 24 February 2024
Accepted 19 April 2024
Lucas Lopes da Silva Costa
Polytechnic Institute of Rio de Janeiro
Nova Friburgo, Brazil
costa.lucas@iprj.uerj.br
ORCID: 0000-0003-1940-0875
Eduardo Cunha Classe
Polytechnic Institute of Rio de Janeiro
Nova Friburgo, Brazil
eduardo.classe@iprj.uerj.br
ORCID: 0000-0002-2405-3946
Lucas da Silva Asth
Polytechnic Institute of Rio de Janeiro
Nova Friburgo, Brazil
lucas.asth@iprj.uerj.br
ORCID: 0000-0002-6189-1068
Luiz Alberto da Silva Abreu
Polytechnic Institute of Rio de Janeiro
Nova Friburgo, Brazil
luiz.abreu@iprj.uerj.br
ORCID: 0000-0002-7634-7014
Diego Campos Knupp
Polytechnic Institute of Rio de Janeiro
Nova Friburgo, Brazil
diegoknupp@iprj.uerj.br
ORCID: 0000-0001-9534-5623
Leonardo Tavares Stutz
Polytechnic Institute of Rio de Janeiro
Nova Friburgo, Brazil
ltstutz@iprj.uerj.br
ORCID: 0000-0003-3005-765X
ISSN:1390-9266 e-ISSN:1390-9134 LAJC 2024
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24
DOI:
LATIN-AMERICAN JOURNAL OF COMPUTING (LAJC), Vol XI, Issue 2, July 2024
10.5281/zenodo.12171420
LATIN-AMERICAN JOURNAL OF COMPUTING (LAJC), Vol XI, Issue 2, July 2024
Estimation of Spatially Dependent Coefficients in
Heterogeneous Media in Diffusive Heat Transfer
Problems
Lucas Lopes da Silva Costa
Postgraduate Program in
Computational Modeling (Universidade
do Estado do Rio de Janeiro)
Polytechnic Institute of Rio de Janeiro
Nova Friburgo, Brazil
costa.lucas@iprj.uerj.br
ORCID: 0000-0003-1940-0875
Luiz Alberto da Silva Abreu
Dept. de Engenharia Mecânica e
Energia (Universidade do Estado do
Rio de Janeiro)
Polytechnic Institute of Rio de Janeiro
Nova Friburgo, Brazil
luiz.abreu@iprj.uerj.br
ORCID:
0000-0002-7634-7014
Eduardo Cunha Classe
Postgraduate Program in
Computational Modeling (Universidade
do Estado do Rio de Janeiro)
Polytechnic Institute of Rio de Janeiro
Nova Friburgo, Brazil
eduardo.classe@iprj.uerj.br
ORCID
: 0000-0002-2405-3946
Diego Campos Knupp
Dept. de Engenharia Mecânica e
Energia (Universidade do Estado do
Rio de Janeiro)
Polytechnic Institute of Rio de Janeiro
Nova Friburgo, Brazil
diegoknupp@iprj.uerj.br
ORCID:
0000-0001-9534-5623
Lucas da Silva Asth
Postgraduate Program in
Computational Modeling (Universidade
do Estado do Rio de Janeiro)
Polytechnic Institute of Rio de Janeiro
Nova Friburgo, Brazil
lucas.asth@iprj.uerj.br
ORCID:
0000-0002-6189-1068
Leonardo Tavares Stutz
Dept. de Engenharia Mecânica e
Energia (Universidade do Estado do
Rio de Janeiro)
Polytechnic Institute of Rio de Janeiro
Nova Friburgo, Brazil
ltstutz@iprj.uerj.br
ORCID : 0000-0003-3005-765X
Abstract This article addresses the solution to the inverse
problem in a one-dimensional transient partial differential
equation with a source term, commonly encountered in heat
transfer modeling for diffusion problems. The equation is utilized
in a dimensionless form to derive a more general solution that is
applicable in various contexts. The Transition Markov Chain
Monte Carlo (TMCMC) method is utilized to estimate spatially
variable thermophysical properties within the equation. This
approach involves transitioning between probability densities,
gradually refining the prior distribution to approximate the
posterior distribution. The results indicate the effectiveness of the
TMCMC method in addressing this inverse problem, and it offers
a robust methodology for estimating spatially variable
coefficients.
KeywordsInverse Problem, Transition Markov Chain
Monte Carlo (TMCMC), Heterogeneous Media, Estimation of
Variable Coefficients, Heat Conduction
I. INTRODUCTION
The identification of thermophysical properties is a
fundamental process in various fields of science and
engineering, where understanding these properties is
essential to comprehend material behavior or identify them.
Properties like thermal conductivity, density, and specific
heat directly influence how a material responds to
temperature changes [4]. When modeling the heat transfer
process, these properties can be expressed through
parameters within partial differential equations [3] [5] [10].
This, in turn, paves the way for varied approaches in
estimating these parameters, ranging from direct methods to
indirect approaches, each carrying its own advantages and
disadvantages.
Within direct methods, direct experimental
measurements on thermophysical properties of material
samples are conducted. While recognized for their
precision, these methods often prove to be costly, time-
consuming, and in certain cases, intrusive to the material
under analysis.
On the other hand, indirect methods offer an attractive
alternative. They do not demand direct measurements of
thermophysical properties but instead explore relationships
between these properties and other variables that can be
more easily measured [1][11]. However, indirect methods
often rely on assumptions and models to establish these
relationships, introducing uncertainties in the estimation.
One particular approach that has gained prominence is
the utilization of Bayesian frameworks, such as the
Transitional Markov Chain Monte Carlo (TMCMC)
method, to estimate thermo-physical properties. The
distinctive feature of Bayesian methods is the incorporation
of prior information, i.e., prior knowledge about the
properties in question [11]. TMCMC, for instance,
constructs a probability distribution that takes into account
both experimental data and prior information, resulting in
more reliable estimates and quantified uncertainties [9] [11].
The aim of this work is to demonstrate the utilization of
the TMCMC technique for computing unspecified
parameters in a differential equation, proposing three
distinct models of their spatial variation. The obtained
results demonstrate the effectiveness of the TMCMC
method in solving the inverse problem, providing a robust
methodology for this type of problem. Furthermore, this
work may validate the use of TMCMC as a reliable and
versatile tool for parameter estimation in different contexts,
paving the way for more advanced applications, such as
characterizing new materials with different thermal
properties.
ISSN:1390-9266 e-ISSN:1390-9134 LAJC 2024
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DOI:
LATIN-AMERICAN JOURNAL OF COMPUTING (LAJC), Vol XI, Issue 2, July 2024
10.5281/zenodo.12171420
L. Costa, E. Classe, L. Asth, L. Abreu, D. Knupp and L. Stutz,
Estimation of Spatially Dependent Coefficients in Heterogeneous Media in Diffusive Heat Transfer Problems”,
Latin-American Journal of Computing (LAJC), vol. 11, no. 2, 2024.
II. M
ETHODOLOGY
In this section, the methodology employed in this study
will be presented. In the subsequent subsections, the
mathematical formulation of the physical problem will be
explained, and the intricacies of Transition Markov Chain
Monte Carlo (TMCMC) will be explored. Introduced by [8],
this approach draws inspiration from the adaptive
Metropolis-Hastings technique and employs Monte Carlo
principles through Markov Chains. A comprehensive
overview of the TMCMC method will be provided,
including discussions on its fundamental principles and
procedural steps. The aim of this exposition is to provide a
clear understanding of how the TMCMC method operates,
especially in the context of estimating coefficients in
solving inverse problems.
A. Mathematical Formulation
In this section, the mathematical formulation underlying
the physical phenomenon of heat transfer within a material
of length L=10 will be delved into. This investigation
considers Neumann boundary conditions coupled with a
constant initial condition. The primary objective of this
section is to model the dynamic evolution of temperature,
represented as T(x,t), across space and time.
w
󰇛
x
󰇜
T(x,t)
∂t
=
∂x
󰇡
k(x)
T(x,t)
∂x
󰇢
+p
󰇛
x
󰇜
(1a)
In this context, k(x) represents the thermal conductivity
coefficient, a measure characterizing an intrinsic ability of a
material to conduct heat. In turn, the coefficient w(x),
known as the thermal diffusion coefficient, incorporates the
inherent thermal diffusivity property of the material in
question. The term p(x) refers to an internal heat source
within the material. The spatial domain is defined in the
interval 0 < x < L, while time is restricted to positive values,
t > 0, where L denotes the physical extent of the material.
These parameters are expressed in terms of Neumann
boundary conditions:
T(x,t)
∂x
󰇻
x=0
= 0
(1b)
T(x,t)
∂x
󰇻
x=L
= 0
(1c)
These expressions characterize the rates of heat transfer
at the material boundaries, and the initial condition is
established as shown below, where T
0
is a constant
representing the initial temperature distribution within the
material.
T(x,0)
=
T
0
(1d)
This study examines Equation (1) in three distinct
scenarios: firstly, when both coefficients k(x) and w(x) are
kept constant; secondly, when they are modeled as linear
functions; and finally, when they follow exponential
functions. The primary aim of these analyses is to assess the
Transitional Markov Chain Monte Carlo (TMCMC) method
ability to accurately estimate these parameters.
Transitional Markov Chain Monte Carlo (TMCMC)
The Transitional Markov Chain Monte Carlo (TMCMC)
method, as proposed by [8], draws inspiration from the
adaptive Metropolis-Hastings method as suggested by [6],
and it is grounded on the Monte Carlo methodology through
Markov Chains. The main idea is to avoid direct sampling
of difficult probability distributions by sampling from a
series of intermediate distributions that converge to the
posterior distribution [8].
This method inherits the advantages of Adaptive
Metropolis-Hastings (AMH), which is suitable for very
sharp, flat, and multimodal probability density functions
(PDFs), and is particularly efficient in high-dimensional
PDFs. Additionally, the TMCMC method has the capability
to automatically select intermediate PDFs, enhancing its
versatility and effectiveness in sampling complex
distributions [8].
The posterior distribution is calculated using Bayes'
theorem, described by Equation (2) [9], as shown below:
π(P
Y)
π(P)π(Y| P) (2)
But, as mentioned earlier, the TMCMC method avoids
computing the distribution in this way, in order to employ a
series of intermediate distributions as follows:
f
j
(P)

π
󰇛
P
󰇜
π󰇛󰇜
p
j
(3)
The steps for the TMCMC algorithm are outlined as
follows [7]:
1. Samples {P₀,₁, P₀,₂, ..., P₀,ₙ} are acquired from the
prior distribution f₀(P) = π(P) using Monte Carlo
simulation. The process initiates with p₀ set to 0, and steps
2 and 3 are repeated for j = {0, 1, 2, ...}.
2. Likelihood distributions π(Y | Pⱼ,₁), ..., π(Y | Pⱼ,ₙ) are
computed, and the weights wⱼ,ₖ = π(Y | Pⱼ,ₖ)^(pⱼ₊₁ - pⱼ) are
determined. The selection of pⱼ₊₁ ensures that the coefficient
of variation (COV) of the importance weights {wⱼ,₁, ...,
wⱼ,ₙ} equals 100%. Additionally, normalized weights {wⱼ,₁,
..., wⱼ,ₙ} are calculated.
3. Based on the normalized weights {wⱼ,₁, ..., wⱼ,ₙ},
candidates are randomly chosen from {Pⱼ,₁, Pⱼ,₂, ..., Pⱼ,ₙ}. A
new candidate is proposed according to the distribution
N(Pⱼ,ₖ, Σⱼ), forming the sequence {Pⱼ₊₁,₁, Pⱼ₊₁,₂, ..., Pⱼ₊₁}. The
covariance matrix Σⱼ is defined by an equation.
j
= β
2
j=1
n
j
w
j,k
󰇣P
j,k
P
j
×P
j,k
P
j
T
󰇤 (4a)
with
P
j
=
l=1
n
j
w
j,1
. P
j,1
l=1
n
j
w
j,l
(4b)
The parameter β is a factor that scales the distribution of the
covariance matrix proposal [8].
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LATIN-AMERICAN JOURNAL OF COMPUTING (LAJC), Vol XI, Issue 2, July 2024
III. R
ESULTS
In this section, the study conducted a comparative
analysis of the parameters w(x) and k(x) estimated in the
Partial Differential Equation (PDE), as mentioned earlier.
Three distinct variations were considered: constant, linear,
and exponential. To obtain experimental measurements in
the direct problem, three spatial measurement points were
selected: x=2.5, x=5.0, and x=7.5, resulting in a total of 101
measurements for each sensor within the analyzed time
interval. The standard deviations of the measurement errors
σ were defined as 0.5 for the constant case, 1.0 for the linear
case, and 1.5 for the exponential case. Therefore, these
experimental measurements are now referred to as actual
measurements. It is worth noting that these measurement
errors were chosen to be proportional to the measured
temperature, specifically around 2%. This choice was based
on the averaging of experimental measurements for each
model.
The Transition Markov Chain Monte Carlo (TMCMC)
method was employed to simultaneously obtain estimates of
these parameters, and the results were compared for each
variation. The study was conducted with a total of 20,000
samples for the Constant model, 50,000 for the Linear
model, and 50,000 for the Exponential model and β = 0.1 in
all three situations. In order to simulate a source with
characteristics of a smooth step curve, the following
mathematical formulation for p(x) was used.
p
(
x
)
=
1-
1
[
1+e
-
100
(
x
-
0.5L
)
]
(6)
The specific formulations and characteristics of the
analyzed models for w(x) and k(x) are detailed in the
following sections, accompanied by their respective
mathematical formulations and corresponding results.
It is important to emphasize that all results presented in
this work were generated using the computational platform
Wolfram Mathematica 12.0, operating on a desktop
equipped with a Central Processing Unit (CPU) AMD
Ryzen Threadripper1950x clocked at 4 GHz and 64 GB of
DDR4 type RAM. The adopted operating system is
Windows 10 in its 64-bit version.
A. Model with Constant Coefficients
Firstly, the TMCMC method was applied to estimate the
parameters of a model with constant coefficients. In the
direct problem, k(x) = 1 and w(x) = 1 were used. Table I
below shows the exact values of the coefficients, as well as
the results obtained after the method was applied.
TABLE I. ESTIMATED RESULTS VIA TMCMC MODEL WITH
CONSTANT COEFFICIENTS
Parameter
Exact
Value
Estimated
Standard
Deviation
Error(%)
w
0
1.00 1.00056 0.00142 0.056
k
0
1.00 1.00641 0.01269 0.641
The table analysis reveals that the method was effective
in parameter estimation, resulting in reduced relative errors
and standard deviations. Fig. 1 depicts a comparison
between estimated values, represented by the blue curve,
and actual measurements denoted by red points, along with
the 95% confidence interval depicted by the blue shaded
region. On the other hand, Fig. 2 presents the residual
analysis of the three utilized sensors, along with their
corresponding linear regression.
Fig. 1. Temperature Measurements with 95% confidence interval -
Model with Constant Coefficients
Fig. 2. Residual analysis Model with Constant Coefficients
Through the analysis of the graphs, it is evident that the
estimated measurements exhibit high agreement with the
actual measurements. The residual analysis reveals that the
differences between these measurements are close to zero
across the entire domain, as evidenced by the linear
regression. Fig.3 and Fig. 4 illustrate the histogram of the
estimates for the parameters w(x) and k(x). It is important
to note that all estimated samples were normalized by their
respective exact values, rendering the histogram
dimensionless.
Fig. 3. Histogram of the w
0
estimated parameter - model with constant
coefficients
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LATIN-AMERICAN JOURNAL OF COMPUTING (LAJC), Vol XI, Issue 2, July 2024
10.5281/zenodo.12171420
L. Costa, E. Classe, L. Asth, L. Abreu, D. Knupp and L. Stutz,
Estimation of Spatially Dependent Coefficients in Heterogeneous Media in Diffusive Heat Transfer Problems”,
Latin-American Journal of Computing (LAJC), vol. 11, no. 2, 2024.
Fig. 4. Histogram of the k
0
estimated parameter - model with constant
coefficients
The means of the estimated values are close to the exact
values, as expected. It is noteworthy that the estimation for
the parameter w(x) was more accurate than for the
parameter k(x).
B. Model with Linear Coefficients
Similarly to the model with constant coefficients, Table
II presents the values used in solving the direct problem for
the case of linear coefficients in the form w
(
x
)
=w
o
x+w
1
and k
(
x
)
=k
0
x+k
1
.The corresponding estimates, standard
deviations, and relative errors are also indicated.
TABLE II. ESTIMATED RESULTS VIA TMCMC - MODEL
LINEAR WITH LINEAR COEFFICIENTS
Parameter
Exact
Value
Estimated
Standard
Deviation
Error(%)
w
0
0.09 0.08992 0.00185 0.091
w
1
0.10 0.10021 0.00857 0.215
w
0
0.09 0.09099 0.00552 1.101
k
1
0.90 0.09117 0.02360 8.832
Except for the parameter k
1
, all estimates yielded
relative errors of less than 3%. Fig. 5 illustrates the
comparison between the measurements of estimated values,
represented by the blue curve, and actual measurements
denoted by red points, along with the 95% confidence
interval depicted by the blue shaded region. Meanwhile,
Fig. 6 displays the residual analysis between these two
measurements and the linear regression of the points.
Fig. 5. Temperature Measurements with 95% confidence interval
Model with Linear Coefficients
Fig. 6. Residual analysis - Model with Linear Coefficients
Once again, a remarkable resemblance is observed
between the estimated measurements and the actual
measurements. However, it is noticeable that for the linear
case, the confidence interval encompasses all the conducted
measurements. The residual analysis demonstrates that the
differences between the measurements are close to zero
across the entire domain, as shown by the linear regression.
Fig. 7, Fig. 8, Fig. 9 and Fig. 10 displays the histograms of
parameter estimates for this case.
Fig. 7. Histogram of the w
0
estimated parameter - model with linear
coefficients
Fig. 8. Histogram of the w
1
estimated parameter - model with linear
coefficients
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Fig. 9. Histogram of the k
0
estimated parameter - model with linear
coefficients
Fig. 10. Histogram of the k
1
estimated parameter - model with linear
coefficients
The means of the estimated values approach the exact
values, as expected, reinforcing the reliability of the
TMCMC method. It is worth noting that the estimate for the
parameter w(x) reveals superior precision compared to the
parameter k(x), suggesting the need for a more in-depth
analysis to comprehend the underlying causes of this
discrepancy.
C. Model with Exponential Coefficients
Finally, Table III showcases the values and estimates of
the parameters associated with the case of exponential
coefficients in the form w
(
x
)
=w
0
e
w
1
x
and k
(
x
)
=k
0
e
k
1
x
.
TABLE III. ESTIMATED RESULTS VIA TMCMC - MODEL WITH
LINEAR COEFFICIENTS
Parameter
Exact
Value
Estimated
Standard
Deviation
Error (%)
w
0
0.10 0.10159 0.00157 1.595
w
1
0.25 0.24738 0.00249 1.046
w
0
0.10 0.10066 0.00226 0.663
k
1
0.25 0.24637 0.00487 1.450
Once again, the estimates resulted in significantly
reduced relative errors and standard deviations. Fig. 11
illustrates the comparison graphs between the
measurements with the estimated parameters, represented
by the blue curve, and the actual measurements denoted by
red points, along with the 95% confidence interval depicted
by the blue shaded region. Meanwhile, Fig. 12 displays the
residual analysis between these measurements with the
linear regression of the points.
Fig. 11. Temperature Measurements with 95% confidence interval -
Model with Exponential Coefficients
Fig. 12. Residual analysis - Model with Exponential Coefficients
Similar to the previous cases, the estimated
measurements exhibit high agreement with the actual
measurements. The residual analysis confirms that the
differences between these measurements are close to zero
across the entire domain. Figs.13, 14, 15 and 16 display the
histograms of parameter estimates for this case.
Fig. 13. Histogram of the w
0
estimated parameter - model with
exponential coefficients
ISSN:1390-9266 e-ISSN:1390-9134 LAJC 2024
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DOI:
LATIN-AMERICAN JOURNAL OF COMPUTING (LAJC), Vol XI, Issue 2, July 2024
10.5281/zenodo.12171420
L. Costa, E. Classe, L. Asth, L. Abreu, D. Knupp and L. Stutz,
Estimation of Spatially Dependent Coefficients in Heterogeneous Media in Diffusive Heat Transfer Problems”,
Latin-American Journal of Computing (LAJC), vol. 11, no. 2, 2024.
Fig. 14. Histogram of the w
1
estimated parameter - model with
exponential coefficients
Fig. 15. Histogram of the k
0
estimated parameter - model with
exponential coefficients
Fig. 16. Histogram of the k
1
estimated parameter - model with
exponential coefficients
It is important to note that despite this change in
distribution, the TMCMC method demonstrated estimating
the parameters with lower relative error compared to the
previous linear cases. This observation underscores the
relative capability of the method in dealing with exponential
coefficients, even with the loss of uniformity in histograms,
indicating a relative precision in estimating these
parameters.
IV. C
ONCLUSION
Throughout this study, the evaluation of the TMCMC
method efficacy in estimating coefficient parameters was
conducted across three distinct scenarios. The analysis of
the obtained tables and histograms reveals variability in the
method efficiency based on the analyzed case. Notably, it
was found that the method faced more significant challenges
in estimating parameters for k(x) in the second scenario,
corresponding to a linear model. Despite this additional
complexity, the relative error consistently remained below
9%.
A detailed analysis of the generated histograms allows
for a deeper understanding of the results. In all investigated
scenarios, a notable precision was observed in estimating
the parameters. In the constant model case, the value
distribution showed a well-defined Gaussian shape,
centered around the exact value, demonstrating highly
accurate estimation. However, in the linear case, there was
a more significant dispersion in the probable values,
especially considering the parameters associated with k(x).
Lastly, in the third case, an even higher precision compared
to the linear case was highlighted, along with the presence
of distributions that appeared to be bimodal, indicating the
occurrence of two peaks of probable values for the k(x)
parameters, something that warrants further investigation.
These results offer a comprehensive insight into the
applicability and performance of the TMCMC method in
parameter estimation, highlighting its nuances across
different model configurations. The achieved accuracy,
even in the face of specific challenges, underscores the
robustness and potential of this method for parameter
analyses and inferences across various contexts.
A
CKNOWLEDGMENT
The present work was supported by the Coordenação de
Aperfeiçoamento de Pessoal de Nível Superior - Brasil
(CAPES) - Funding Code 001.
The authors also acknowledge the financial support
from the CNPq and FAPERJ funding agencies.
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LATIN-AMERICAN JOURNAL OF COMPUTING (LAJC), Vol XI, Issue 2, July 2024
AUTHORS
Lucas Lopes da Silva Costa. (São Sebastião do Alto, Rio de
Janeiro, Brazil, July 11th, 1999). B.Sc. in Applied and Computational
Mathematics from Fluminense Federal University (UFF), Brazil, 2021.
Currently pursuing a Master's degree in Computational Modeling
at the State University of Rio de Janeiro UERJ), which began in
2022, aiming to deepen knowledge in Applied Mathematics and
Scientific Computing. During his undergraduate studies, he actively
participated in the Mathematics of Epidemics extension project
(PEB) and contributed as a student member in course coordination.
Alongside his master's studies, he is also pursuing a Teaching Degree
in Mathematics at UFF, demonstrating a strong commitment to
pedagogical training. Additionally, he gained practical experience as
an intern in the Education sector with the Municipal Government of
Macuco - RJ, applying theoretical knowledge in a real-world context
between 2021 and 2022. His research interests include mathematical
modeling, computational simulation, and educational methodologies
in mathematics.
Eduardo Cunha Classe, Nova Friburgo, Rio de Janeiro, Brazil, April
29, 1998. B.Sc. in Mechanical Engineering from the State University
of Rio de Janeiro (UERJ), 2021. During his undergraduate studies, he
participated in a scientific initiation project for the characterization of
corrosion resistance of stainless steel alloys, was a member of the Baja
SAE program, and a member of the SPE student chapter. Currently
pursuing a Master's degree in Computational Modeling at the same
university, which began in 2022, aiming to deepen his knowledge in
heat transfer and computational modeling.
Lucas da Silva Asth (Nova Friburgo, Brazil, November 25th, 1996).
B.Sc. in Mechanical Engineering from the State University of Rio de
Janeiro, Brazil, 2021. MSc (2024) and currently pursuing a Ph.D. in
Computational Modeling at the State University of Rio de Janeiro
(UERJ). his research interests include heat and mass transfer, structural
dynamics, inverse problems and optimization.
Lucas L. da Silva Costa
Eduardo Cunha Classe
Lucas da Silva Asth
L. Costa, E. Classe, L. Asth, L. Abreu, D. Knupp and L. Stutz,
“Estimation of Spatially Dependent Coecients in Heterogeneous Media in Diusive Heat Transfer Problems”,
Latin-American Journal of Computing (LAJC), vol. 11, no. 2, 2024.
ISSN:1390-9266 e-ISSN:1390-9134 LAJC 2024
32
LATIN-AMERICAN JOURNAL OF COMPUTING (LAJC), Vol XI, Issue 2, July 2024
AUTHORS
Luiz A. S. Abreu was born in Nova Friburgo, Brazil, on December 15th,
1982. He obtained his B.Sc. in mechanical engineering from the Rio
de Janeiro State University (UERJ) in 2009, his M.Sc. in mechanical
engineering from the Federal University of Rio de Janeiro (UFRJ) in
2011 and his D.Sc. in mechanical engineering from the same university
in 2014. He has been an aliate member of the ABCM—Brazilian
Society of Mechanical Sciences and Engineering since 2016. He has
advised or co-advised over 12 DSc and MSc theses, most of them
in the Graduate Program in Computational Modeling (PPGMC) at
UERJ. He is the author of over 20 articles published in major scientific
journals and conference proceedings and 5 book chapters. His
research interests include the solution of inverse problems, as well
as the use of meshfree, numerical, analytical, and hybrid numerical–
analytical methods for solving direct problems, mainly in mechanical
engineering applications.
Diego C. Knupp (Nova Friburgo, Brazil, November 9th, 1984). B.Sc. in
Mechanical Engineering from the State University of Rio de Janeiro,
Brazil, 2009. MSc (2010) and DSc (2013) in Mechanical Engineering
from the Federal University of Rio de Janeiro, Brazil. Currently
Professor of Mechanical Engineering at the State University of Rio
de Janeiro at the Polytechnique Institute - IPRJ/UERJ, heads the
Laboratory Patricia Oliva Soares of Experimentation and Numerical
Simulation in Heat and Mass Transfer, LEMA. Author of around 200
articles in major journals and conferences and one book published
abroad. Advisor of over 18 DSc and MSc thesis, his research interests
include hybrid methods, bioheat transfer, structural dynamics, inverse
problems and optimization.
Prof. Knupp has been aliate member of the Brazilian Academy of
Sciences (2019-2023) and currently serves as associate editor for the
Annals of the Brazilian Academy of Sciences journal.
Leonardo Tavares Stutz, Brazilian, born in Nova Friburgo, Rio de
Janeiro. He is currently Associate Professor at the Polytechnique
Institute (IPRJ) of the State University of Rio de Janeiro (UERJ),
Brazil, since 2006. He has Bachelor’s degree (1997), Master degree
(1999) and a Ph.D. (2005) in Mechanical Engineering from the
Federal University of Rio de Janeiro (UFRJ), Brazil. He is the author
of over forty articles published in scientific journals and conference
proceedings. He supervised over fourteen maters dissertations and
doctoral thesis in the Graduate Program in Computational Modeling
(PPGMC) at IPRJ. His research interests include Structural Dynamics
and Vibration, Vibration Damping, Inverse Problems, Parameter
Estimation, Bayesian Inference and Computational Modelling. Much
of his work has been on structural damage identification problems
and on viscoelastic parameter estimation problems.
Luiz Alberto da Silva Abreu
Diego Campos Knupp
Leonardo Tavares Stutz
L. Costa, E. Classe, L. Asth, L. Abreu, D. Knupp and L. Stutz,
“Estimation of Spatially Dependent Coecients in Heterogeneous Media in Diusive Heat Transfer Problems”,
Latin-American Journal of Computing (LAJC), vol. 11, no. 2, 2024.