Results

**1 - 10**of**10**### Calibration and Rescaling Principles for Nonlinear Inverse Heat Conduction and Parameter Estimation Problems

, 2015

"... I am submitting herewith a dissertation written by Yinyuan Chen entitled "Calibration and Rescaling Principles for Nonlinear Inverse Heat Conduction and Parameter Estimation Problems. " I have examined the final electronic copy of this dissertation for form and content and recommend that i ..."

Abstract
- Add to MetaCart

(Show Context)
I am submitting herewith a dissertation written by Yinyuan Chen entitled "Calibration and Rescaling Principles for Nonlinear Inverse Heat Conduction and Parameter Estimation Problems. " I have examined the final electronic copy of this dissertation for form and content and recommend that it be accepted in

### MAGNETOHYDRODYNAMIC OPTIMIZATION OF THE FLUID FLOW DURING THE SOLIDIFICATION OF BINARY MIXTURES IN ENCLOSURES

"... Abstract. In this paper we propose a multilevel approach based on our previously developed hybrid optimizer to solve a double-diffusive fluid flow, during the phase-change, in the presence of magnetic body forces. The problem consists of a square cavity subjected to a thermosolutal flow where the pa ..."

Abstract
- Add to MetaCart

Abstract. In this paper we propose a multilevel approach based on our previously developed hybrid optimizer to solve a double-diffusive fluid flow, during the phase-change, in the presence of magnetic body forces. The problem consists of a square cavity subjected to a thermosolutal flow where the patterns of the isoconcentration are prescribed. Thus, the optimization problem is formulated in terms of the magnetic boundary conditions that must induce such prescribed concentration profile. The optimizer is based on several deterministic and evolutionary algorithms with automatic switching among them, combining the best features of each one. The code was validated, in some previous work, against transient benchmark results for thermosolutal problems with and without phase change.

### Identification of Parameters in a System of Differential Equations Modeling Evolution of Infectious Diseases

"... ABSTRACT The objective of this project was to perform an inverse parameter identification study to determine parameter values in a system of ten ordinary differential equations modeling the prediction of the evolutionary spread of syphilis. The goal was to predict infant mortality rates due to syph ..."

Abstract
- Add to MetaCart

ABSTRACT The objective of this project was to perform an inverse parameter identification study to determine parameter values in a system of ten ordinary differential equations modeling the prediction of the evolutionary spread of syphilis. The goal was to predict infant mortality rates due to syphilis by using this model and match them to actual field data collected in the United States from 1900 to 1970. The syphilis model was developed by the UCLA Disease Modeling Group. The model involves 23 unknown user-specified parameters, each with specified maximum and minimum possible values. An accurate ordinary differential equation system integration algorithm was used to numerically integrate these equations. 1 Undergraduate student. Student member ASME. 2 Professor and Chairman, MME Department. Director of MAIDROC Laboratory. Fellow ASME. 3 Professor and Head of Disease Modeling Group. 4 Associate Professor. Visiting Scientist at FIU. 5 Graduate student. A hybrid evolutionary optimization algorithm was then used to iteratively find the proper values of the 23 unknown parameters by minimizing the difference between the predicted and the actual values of annual infant mortality rates due to syphilis. The parameters were originally treated as constants, meaning that they did not vary in time. During this study, they were also considered as time-dependent by modeling them as second degree polynomials. The sexually active population in the original model was assumed linearly increasing with time. To improve on the results, an eight term Fourier series fit was performed on the actual evolution of the sexually active population data during period 1900-1970. It was found that treating the 23 parameters as constants yielded an average fit of the infant mortality rates. By treating the parameters as time-dependent the fit still appeared average, but the variations of mortality during certain periods were captured more accurately. Copyright © 2008 by ASME NOMENCLATURE α = proportion of sexually active population (N) that are reproductive age women β 1 = primary transmission probability β 2 = secondary transmission probability γ = birth rate δ = rate at which protective immunity wanes µ = entry and exit rate from sexually active population φ = proportion entering remission ρ = rate of relapse from remission to secondary disease ν = adult mortality due to syphilis C 1 = C 2 rate of change of sexual partners σ 1 = rate of progression from incubating to primary disease σ 2 = rate of progression from primary to secondary disease σ 3 = rate of progression from secondary disease to (remission + latent) σ 4 = rate of progression from latent to tertiary disease τ 1 = treatment rate of primary disease τ 2 = treatment rate of secondary disease τ 3 = treatment rate of remission τ 4 = treatment rate of latent τ 5 = treatment rate of tertiary τ 6 = treatment rate of infants κ 1 = probability of transmission from mother with primary or secondary or remission disease to infant κ 2 = probability of transmission from mother with latent or tertiary disease to infant π = death rate of infants due to syphilis ө = natural death rate of infants ( ) t ψ = general time-dependent parameter Obj = objective function R = infant mortality rate t = time t total = total study time (69 years)

### ELECTRO-THERMO-HYDRODYNAMIC CONTROL OF SOLIDIFICATION OF BINARY MIXTURES

"... In this paper we apply a multilevel hybrid optimization algorithm based on a response surface methodology to control the solidification process of a double-diffusive fluid flow, during the phase-change, in the presence of electric and thermal body forces. The problem consists of a rectangular cavity ..."

Abstract
- Add to MetaCart

In this paper we apply a multilevel hybrid optimization algorithm based on a response surface methodology to control the solidification process of a double-diffusive fluid flow, during the phase-change, in the presence of electric and thermal body forces. The problem consists of a rectangular cavity subjected to a thermosolutal flow containing electrically charged particles where the patterns of the isothermal fields for the solute are prescribed. The optimization problem is formulated in terms of the electric and thermal boundary conditions that must induce such prescribed temperature profile. Thus, it is essentially an inverse problem that is solved by determining the appropriate electric and thermal boundary conditions. The electro-thermo-hydrodynamics analysis including solidification was performed using our implicit algorithm on a fixed structured grid. The optimizer is based on several deterministic and evolutionary algorithms with automatic switching among them, combining the best features of each one. The response surface methodology uses several radial basis function interpolants in order to significantly reduce the high computational cost involved during the optimization process of the electric and thermal boundary conditions. The entire numerical simulation was performed on our 96-processor Opteron based parallel computer running Linux and MPI.

### Reduced Model For Parameter Estimation In Coupled Conduction-Radiation

, 2005

"... The physical problem considered in this work involves the heating of a semi-transparent material by a high-power laser, where conduction and radiation are the coupled mechanisms of heat transfer. Both the conduction and the radiation problems are solved numerically with finite-volumes. The main obje ..."

Abstract
- Add to MetaCart

The physical problem considered in this work involves the heating of a semi-transparent material by a high-power laser, where conduction and radiation are the coupled mechanisms of heat transfer. Both the conduction and the radiation problems are solved numerically with finite-volumes. The main objective of this work is to examine the use of reduced models, where radiation and conduction are decoupled, for the solution of an inverse parameter estimation problem. The use of the reduced model is examined for the computation of the system response (direct problem) and for the computation of the gradient. The inverse problem is solved by using a Hybrid minimization algorithm, which involves gradient and stochastic algorithms. 2. Keywords: Heat transfer, inverse problem, coupled problem, hybrid method, reduced model The identification of thermophysical properties plays an important role in today’s research and development in engineering, which deeply relies on computational simulation of physical phenomena for design purposes. The commercial codes available today, as well as those specially developed for specific designs, require several parameters as input data, including the physical properties of those materials considered in the design.

### Inverse Problem of Estimation of the Blood Perfusion Coefficient in Cancerous Tissues

"... The success of the treatment of malignant tumors by hyperthermia calls for the knowledge of the temperature field for both healthy and cancerous tissues. This medical procedure consists in exposing malignant cells to temperatures in the range of 42°C to 45 ° C in order to retard, stop or reverse the ..."

Abstract
- Add to MetaCart

(Show Context)
The success of the treatment of malignant tumors by hyperthermia calls for the knowledge of the temperature field for both healthy and cancerous tissues. This medical procedure consists in exposing malignant cells to temperatures in the range of 42°C to 45 ° C in order to retard, stop or reverse the growth of tumors. Although susceptible to the increase in temperature, the normal cells do not exhibit the same degree of sensitivity as the malignant cells and therefore the potential of induced hyperthermia as a therapy for cancer has been long considered for both local and global treatments. For the case of local hyperthermia, it is important to predict and control the thermal fields generated by the external medical device responsible for increasing local temperature. However, the task of controlling both temperature levels and duration of the heating process cannot be satisfactory accomplished based solely on measurements because only a few localized temperature readings can be monitored during the therapy. Therefore, mathematical models commonly employed in engineering are often used in the simulation of the heat transfer in living tissues, furnishing temperature profiles that may guide the physician before and after the treatment. One of these models is the bioheat transfer equation proposed by Pennes [1] that consists in a heat diffusion equation together with an energy sink term that accounts for the effect of the temperature difference between the blood supply and the tissue. The source term of this equation carries a combined effect of the internal metabolic heat generation and the external irradiation of the treatment. In this work, a parameter estimation produce based on several optimization methods [2, 3] was employed, in order to determine the perfusion coefficient of Pennes ’ model.

### Parallel Genetic Algorithm in Electrical Impedance Tomography

"... This paper presents the basic concepts of parallel genetic algorithms models for global minimum search and compares the efficiency of these models when applied to the electrical impedance tomography (EIT) problem. Master-slave, island and cellular models of parallel genetic algorithm are described i ..."

Abstract
- Add to MetaCart

(Show Context)
This paper presents the basic concepts of parallel genetic algorithms models for global minimum search and compares the efficiency of these models when applied to the electrical impedance tomography (EIT) problem. Master-slave, island and cellular models of parallel genetic algorithm are described in details. The master-slave model simultaneously evaluates the individuals on different processors [3]. The island model has subpopulations that may exchange information according to various patterns by allowing some individuals to migrate from one subpopulation to another [1]. The cellular

### Automatic Switching Algorithms in Hybrid Single-Objective Optimization

"... Hybrid optimization algorithms consist of a number of proven constituent optimization algorithms and a control algorithm that performs automatic switching among the constituent algorithms at each stage during the optimization when the rate of convergence becomes unsatisfactory, the process tends tow ..."

Abstract
- Add to MetaCart

Hybrid optimization algorithms consist of a number of proven constituent optimization algorithms and a control algorithm that performs automatic switching among the constituent algorithms at each stage during the optimization when the rate of convergence becomes unsatisfactory, the process tends towards a local minimum, or some other undesirable aspect of the iterative process appears. Thus, hybrid optimization algorithms that utilize a number of gradient based and non-gradient based constituent optimizers are more robust and converge better than individual constituent optimization algorithms. The logic of designing the automatic switching algorithms in hybrid optimizers is surveyed in this paper focusing on the research performed by the authors in the area of hybrid single-objective optimization initiated in 1997.

### systems associated with multiphase

"... Study of methods for the resolution of large sparse linear ..."

(Show Context)
### unknown title

, 2007

"... This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or sel ..."

Abstract
- Add to MetaCart

(Show Context)
This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier’s archiving and manuscript policies are encouraged to visit: