We propose and compare two approaches for regression analysis of multilevel binary data when clusters are not necessarily nested: a GEE method that relies on a working independence assumption coupled with a three-step method for obtaining empirical standard errors, and a likelihood-based method implemented using Bayesian computational techniques. Implications of time-varying endogenous covariat...

This paper explains a control strategy SHE-PWM and a closed loop control of the cascaded multilevel inverter based on the modulation index. The modulation index is taken as the feedback to the cascaded multilevel inverter, the proposed system reduces the total harmonic distortion by optimizing the angles of the inverter and the DC voltage sources applied to the cascaded inverter. The specific l...

Direct Search algorithms are classical derivative-free methods for optimization. Though endowed with solid theoretical properties, they are not well suited for large-scale problems due to slow convergence and scaling issues. In this paper, we discuss how such limitations can be circumvented, on problems for which a hierarchy of objective functions is available, by using multilevel schemes which...

this study investigated the efficiency of wheat farms in sistan province. the data consisted of 50 samples from crop producers in the sistan region. using the simple sampling method, the data was collected by completing the questionnaires. to evaluate the farm efficiencies, the two approaches of the “data envelopment analysis” and the “optimization model including parameters to control for the ...

This study deals with performance-based design optimization (PBDO) of steel moment frames employing four different metaheuristics consisting of genetic algorithm (GA), ant colony optimization (ACO), harmony search (HS), and particle swarm optimization (PSO). In order to evaluate the seismic capacity of the structures, nonlinear pushover analysis is conducted (PBDO). This method is an iterative ...

In this paper an optimization framework is presented for automated performance-based seismic design of bridges consisting of multi-column RC pier substructures. The beneficial effects of fusing components on seismic performance of the quasi-isolated system is duly addressed in analysis and design. The proposed method is based on a two-step structural analysis consisting of a linear modal dynami...

Multilevel design problems are typically decomposed into a hierarchy of distributed and strongly coupled sub-problems, each solved by design teams with specialized knowledge and tools. There are two contrasting approaches to formulating and solving such collaborative design problems: (1) highly iterative exchanges of single design solutions, as in point-based optimization approaches, and (2) mi...