The Wisdom of Crowds, an innovative theory described in social science, claims that the aggregate decisions made by a group will often be better than those of its individual members if the four fundamental criteria of this theory are satisfied. This theory used for in clustering problems. Previous researches showed that this theory can significantly increase the stability and performance of...

In this work, we report the experimental implementation of a Quantitative Feedback Theory (QFT) based robust controller, designed online using hybrid global optimization and constraint propagation techniques. The hybrid global optimization combines interval global optimization and nonlinear local optimization methods. The constraint propagation techniques are very effective in discarding infeas...

This paper proposes an optimization algorithm for the automatic design of robust PID controllers using Quantitative Feedback Theory (QFT) specifications. The proposed algorithm is based on a criterion to minimize the energy of the control effort. To illustrate the methodology, the pitch angle of a laboratory helicopter is used as a model application with structured uncertainty. The results show...

This paper proposes an efficient algorithm for automatic loop shaping in Quantitative Feedback Theory(QFT). The proposed method uses hybrid optimization and consistency techniques. Hull consistency is used to prune the input domain by removing the inconsistent values which are not a part of the solution. The hybrid optimization part combines interval global optimization and nonlinear local opti...

the quantitative structure–activity relationship of a series of novel thiazoline derivatives with anticancer activity has been studied by using the density functional theory by b3lyp/ 6-31g. descriptors of quantum mechanics of 21 thiazoline derivatives with known activity were obtained. multiple linear regressions were employed to model the relationships between molecular descriptors and biolog...

Success of a control design is usually measured by the robustness and optimality of the controller obtained, however, these designs can produce extremely fragile controllers, in the sense that small perturbations of the coefficients of the controller can destabilize the closed loop system. In previous papers, we have described several approaches, such as modern control theory, the norms H2/H in...

This paper presents the design of a robust controller for a vehicle air suspension system using Quantitative Feedback Theory (QFT). This study is primarily focused on control of linearized active air suspension system. For the purpose of simplicity, the dynamics of the air suspension system is modeled using a simple 2-DOF quarter car model. Uncertain dynamic system with different working condit...

A magnetic levitation (maglev) system is inherently nonlinear and open-loop unstable because of the nature of magnetic force. Most controllers for maglev systems are designed based on a nominal linearized model. System variations and uncertainties are not accommodated. The controllers are generally designed to satisfy gain and phase margin specifications, which may not guarantee a bound on the ...

This paper presents theoritical and experimental design of a robust control based on quantitative feedback theory (QFT) approach to control deepness variations on cutting process for a spindle of lathe machine. The dynamics of a spindle is uncertain and varying due to deepness variation on cutting process. Practical design steps are explained in which QFT based conditions are assembled to obtai...

this paper investigates learner-initiated responses to english language teachers’ referential questions and learner initiatives after teachers’ feedback moves in meaning-focused question-answer sequences to analyze how interactional practices of language teachers, their initiation and feedback moves, facilitate learner initiatives. classroom discourse research has largely neglected learner init...