Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 49 for “"Nonlinear least-squares"”.
-
MULTI-MODEL ALGORITHMS FOR OPTIMIZATION (TRUST REGIONS, NONLINEAR LEAST SQUARES, SECANT, HYBRID METHODS, MODEL SWITCHING)
A recent approach for the construction of nonlinear optimization software has been to allow an algorithm to choose between two possible models to the objective function at each iteration. The model switching algorithm NL2SOL of Dennis, Gay and Welsch and the hybrid algorithms of Al-Baali and …
-
Information Geometry For Nonlinear Least-Squares Data Fitting And Calculation Of The Superconducting Superheating Field
… explore the information geometric properties of least squares data fitting, particularly for so-called "sloppy" models. Second we describe a calculation of the superconducting superheating field, relevant for advancing gradients in particle accelerator resonance cavities. Parameter estimation by …
-
A nonlinear least squares inversion to the single-scattering three-dimensional radiative transfer equation for satellite-based tomography
… commonly found in medical imaging. A non-linear least squares inversion model was developed to reconstruct the distribution of scattering properties in a heterogeneous domain. The inverse model produced excellent reconstructions in many cases, demonstrating the correctness of our formulation. …
-
Scaling rank-one updating formula and its application in unconstrained optimization
… and. the detection of large residual in nonlinear least squares problems. The thesis consists of two parts. The first part gives a brief survey of unconstrained optimization. It contains four chapters, and introduces basic results on unconstrained optimization, some popular methods and …
-
Scaling rank-one updating formula and its application in unconstrained optimization
… and. the detection of large residual in nonlinear least squares problems. The thesis consists of two parts. The first part gives a brief survey of unconstrained optimization. It contains four chapters, and introduces basic results on unconstrained optimization, some popular methods and …
-
Estimation of the In-Cylinder Air/Fuel Ratio of an Internal Combustion Engine by the Use of Pressure Sensors
… exponent. The first method results in a linear least-squares problem, and the second method results in a nonlinear least-squares problem. The nonlinear least-squares problem is solved by separating out the nonlinear dependence and solving the single-variable minimization problem. For this, a …
-
Quasi-Newton algorithms for large scale nonlinear systems
… applied to the unconstrained minimization of a nonlinear function as well as a nonlinear least squares approach to solving a system of nonlinear equations. The best of these algorithms were evaluated for a problem with a fairly large number of degrees of freedom with a large load increment. From …
-
Determination of Reactivity Ratios for Acrylonitrile/Methyl Acrylate Radical Copolymerization Via Nonlinear Methodologies Using Real Time FTIR
… compositions, which permitted application of nonlinear least squares methodology for the first time to this copolymer system. Thus, reactivity ratios at the 95% confidence level were determined to be 1.29 ± 0.2 and 0.96 ± 0.2 for acrylonitrile and methyl acrylate, respectively. The results are …
-
Statistical Preconditioning and Quantitative Imaging for Electrical Impedance Tomography
… problems frequently give rise to linear or nonlinear least squares problems, and if the problems are large, iterative solvers are typically the method of choice, with the Krylov subspace methods a frequently used family of iterative schemes. In the case of nonlinear least squares problems, …
-
Determination and interpretation of earthquake source locations in Sichuan Province, China
… method is applied iteratively to find the nonlinear least squares solution. The Monte Carlo method and the Gauss- Newton method were jointly used to locate events and simultaneously optimize the crust model. The iterative station correction method is adopted to compensate the incorrectness …
-
Towards the improved robustness of acoustic cooperative localization
… vehicle. Trajectory estimates, computed using nonlinear least squares optimization, are computed for a variety of client node/server code configurations, and for a series of packet transmission success rates in one of those configurations. Though it is possible for a vehicle to receive some …
-
Intermolecular potential combining rules utilizing corresponding states correlations for pure substances having nonspherical molecules
… are calculated from the data by means of a nonlinear, least squares curve fitting technique. Correlations are given for the potential parameters of each substance in terms of its critical temperature, critical volume, and acentric factor. The accuracy of these correlations is near to that of …
-
Toward robust active semantic SLAM via Max-Mixtures
… multimodal belief in a manner compatible to nonlinear least squares solvers. Experimental results are presented using a RACECAR mobile robot operating in several hallways of MIT, using AprilTags as surrogates for objects in the Semantic Max Mixtures Algorithm. Future work will seek to further …
-
A dynamic model of the U.S. cotton market with rational expectations
… for cotton is estimated by using the method of nonlinear least squares and tested by using the likelihood ratio. The empirical results provide some support for the specific model. Furthermore, the empirical model provides a framework for policy evaluation.</p>
-
Tax effects and term structure measurement.
… government bonds with a regression methodology. Nonlinear least squares is used to simultaneously estimate the after-tax term structure and the corresponding implied tax rates. The estimation is performed on each group separately and on the entire sample. The null hypothesis is that the sets of …
-
Underwater vehicle localization using range measurements
… Using the weak observability theorem for nonlinear systems, we demonstrate that this cooperative localization problem is best attacked using nonlinear least squares (NLS) optimization. We investigate the convergence of NLS applied to the cooperative ASV/AUV localization problem. Though we …
-
Optimal experimental design applied to DC resistivity problems
… where the inversion is approached via nonlinear least squares with L1 smoothness constraints. An equally important goal is to find ways to expedite experimental design to make it practical for a wider variety of surveying situations than is currently possible.A fast, sequential ED …
-
Thermal Characterization of Complex Aerospace Structures
… (HSCT) wing tip. Due to the nature of the nonlinear least-squares estimation method used in this study, both theoretical and experimental temperature histories were required. Several one-dimensional and two-dimensional finite element models of the OWS were developed to compute the transient …
-
Biodegradation of Benzene
… at 540 nm in order to assess the growth rate. A nonlinear least-squares regression technique was employed to estimate the constants of the Haldane equation (an inhibition function). µ<sub>m</sub> was 0.31 hr⁻¹, K₂ was 1.36 mg/I and K<sub>i</sub>, was 1.50x10¹⁵' mg/I in the range of 14 - 491 mg/I …
-
Modeling the impact of gypsy moth defoliation in individual tree mortality and basal area growth of northern hardwoods of central Pennsylvania
… the same 15 species. The models were fit using nonlinear least squares. Variables used include the relative basal area index, stand basal area, site index and a defoliation index that incorporated three years of individual-tree, percent defoliation. The beta and gamma functions fit equally well …
Page 1 of 3