Inference of Complete Tissue Temperature Fields from a Few Measured Temperatures: An Unconstrained Optimization Method

1984 ◽  
Vol BME-31 (1) ◽  
pp. 150-160 ◽  
Author(s):  
A. Murat Divrik ◽  
Robert B. Roemer ◽  
Thomas C. Cetas
Keyword(s):  
Unconstrained Optimization ◽  
Optimization Method ◽  
Temperature Fields ◽  
Tissue Temperature

A Comparative Evaluation of Unconstrained Optimization Methods Applied to the Thermal Tomography Problem

1985 ◽  
Vol 107 (3) ◽  
pp. 228-233 ◽  
Author(s):  
S. T. Clegg ◽  
R. B. Roemer
Keyword(s):  
Unconstrained Optimization ◽  
Blood Perfusion ◽  
Optimization Methods ◽  
Sensitivity Study ◽  
Initial Guess ◽  
Optimization Techniques ◽  
Temperature Fields ◽  
Tissue Temperature ◽  
Initial Attempt ◽  
Error Space

In cancer hyperthermia treatments, it is important to be able to predict complete tissue temperature fields from sampled temperatures taken at the limited number of locations allowed by clinical constraints. An initial attempt to do this automatically using unconstrained optimization techniques to minimize the differences between experimental temperatures and temperatures predicted from treatment simulations has been previously reported [1]. This paper reports on a comparative study which applies a range of different optimization techniques (relaxation, steepest descent, conjugate gradient, Gauss, Box-Kanemasu, and Modified Box-Kanemasu) to this problem. The results show that the Gauss method converges more rapidly than the others, and that it converges to the correct solution regardless of the initial guess for the unknown blood perfusion vector. A sensitivity study of the error space is also performed, and the relationships between the error space characteristics and the comparative speeds of the optimization techniques are discussed.

Inverse Approaches to Drying of Thin Bodies With Significant Shrinkage Effects

2006 ◽  
Vol 129 (3) ◽  
pp. 379-386 ◽  
Author(s):  
Gligor H. Kanevce ◽  
Ljubica P. Kanevce ◽  
Vangelce B. Mitrevski ◽  
George S. Dulikravich ◽  
Helcio R. B. Orlande
Keyword(s):  
Information Matrix ◽  
Optimization Method ◽  
Moisture Diffusivity ◽  
Temperature Fields ◽  
Convective Drying ◽  
Simultaneous Estimation ◽  
Transfer Coefficients ◽  
Unknown Parameters ◽  
Shrinkage Effect ◽  
Single Temperature

This paper deals with the application of inverse concepts to the drying of bodies that undergo changes in their dimensions. Simultaneous estimation is performed of moisture diffusivity, together with the thermal conductivity, heat capacity, density, and phase conversion factor of a drying body, as well as the heat and mass transfer coefficients and the relative humidity of drying air. This was accomplished by using only temperature measurements. A mathematical model of the drying process of shrinking bodies has been developed where the moisture content and temperature fields in the drying body are expressed by a system of two coupled partial differential equations. The shrinkage effect was incorporated through the experimentally obtained changes of the specific volume of the drying body in an experimental convective dryer. The proposed method was applied to the process of drying potatoes. For the estimation of the unknown parameters, the transient readings of a single temperature sensor located in the midplane of the potato slice, exposed to convective drying, have been used. The Levenberg–Marquardt method and a hybrid optimization method of minimization of the least-squares norm are used to solve the present parameter estimation problem. Analyses of the sensitivity coefficients and of the determinant of the information matrix are presented as well.

scholarly journals Application of inverse concepts to drying

2005 ◽  
Vol 9 (2) ◽  
pp. 31-44 ◽  
Author(s):  
Ljubica Kanevce ◽  
Gligor Kanevce ◽  
George Dulikravich
Keyword(s):  
Optimization Method ◽  
Temperature Fields ◽  
Convective Drying ◽  
Simultaneous Estimation ◽  
Transfer Coefficients ◽  
Sensitivity Matrix ◽  
Unknown Parameters ◽  
Body Dimension ◽  
Drying Time ◽  
Single Temperature

This paper deals with the application of inverse approaches to estimation of drying body parameters. Simultaneous estimation of the thermo physical properties of a drying body as well as the heat and mass transfer coefficients, by using only temperature measurements, is analyzed. A mathematical model of the drying process has been developed, where the moisture content and temperature fields in the drying body are expressed by a system of two coupled partial differential equations. For the estimation of the unknown parameters, the transient readings of a single temperature sensor located in an infinite flat plate, exposed to convective drying, have been used. The Levenberg-Marquardt method and a hybrid optimization method of minimization of the least-squares norm are used to solve the present parameter estimation problem. An analysis of the influence of the drying air velocity, drying air temperature, drying body dimension, and drying time on the thermophysical properties estimation, that enables the design of the proper experiments by using the so-called D-optimum criterion was conducted. In order to perform this analysis, the sensitivity coefficients and the sensitivity matrix determinant were calculated for the characteristic drying regimes and the drying body dimensions.

scholarly journals A New Unconstrained Optimization Method for Imprecise Function and Gradient Values

1996 ◽  
Vol 197 (2) ◽  
pp. 586-607 ◽  
Author(s):  
M.N. Vrahatis ◽  
G.S. Androulakis ◽  
G.E. Manoussakis
Keyword(s):  
Unconstrained Optimization ◽  
Optimization Method

THE EFFECT OF THE DOUBLE-DECK FILAMENT SETUP ON ENHANCING THE UNIFORMITY OF TEMPERATURE FIELD ON LONG-FLUTE CUTTING TOOLS

2014 ◽  
Vol 21 (06) ◽  
pp. 1450078 ◽  
Author(s):  
BIN SHEN ◽  
SULIN CHEN ◽  
LEI CHENG ◽  
FANGHONG SUN
Keyword(s):  
Temperature Field ◽  
Cutting Tools ◽  
Simulation Method ◽  
Optimization Method ◽  
Temperature Fields ◽  
Measured Temperature ◽  
Uniform Temperature ◽  
Uniform Temperature Field ◽  
Flute Surface ◽  
Highly Uniform

In the present study, a double-deck filament setup is proposed for the hot filament chemical vapor deposition (HFCVD) method and an optimization method is presented to determine its optimal geometry that is able to produce a highly uniform temperature field on the whole flute surface of long-flute cutting tools. The optimization method is based on the finite volume method (FVM) simulation and the Taguchi method. The simulation results show that this double-deck filament setup always produce a highly uniform temperature distribution along the filament direction. Comparatively, for the temperature uniformity along the drill axis, the heights of the two filament decks present virtually significant influence, while the separations between the two filaments in either deck exhibit a relative weak effect. An optimized setup is obtained that can produce a highly uniform temperature field with an average temperature of 834°C, a standard deviation (σ) of 2.59°C and a temperature range (R) of 11.75°C. Finally, the precision of the proposed simulation method is verified by an additional temperature measurement. The measured temperature results show that a highly uniform temperature fields with σ/R = 9.6/35.2°C can be generated by the optimized setup and the deviation of the simulated results from the measured actual temperatures are within 0.5–3.5%, which justifies the correctness of the simulation method proposed in present study.

THE SCALING OF HYBRID METHOD IN SOLVING UNCONSTRAINED OPTIMIZATION METHOD

2016 ◽  
Vol 99 (7) ◽  
pp. 983-991 ◽  
Author(s):  
Mohd Asrul Hery Ibrahim ◽  
Mustafa Mamat ◽  
Puspa Liza Ghazali ◽  
Zabidin Salleh
Keyword(s):  
Unconstrained Optimization ◽  
Hybrid Method ◽  
Optimization Method
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