Search results for "ITC"

On the stability analysis for impulsive switching system with time-varying delay

2014

This paper focuses on the stability and stabilization problem for a neutral impulsive switching system with time-varying delay. Based on LMI method and optimization technologies, some stability criteria are derived for this kind of system. Some example and numerical simulation are given to demonstrate the effectiveness of our theoretical results. Refereed/Peer-reviewed

Wavelet-Based Optimal Control of a Wind Turbine System: A Computational Approach

2011

This paper deals with a computational optimization approach to the problem of state-feedback control design for a wind turbine system. The first step of the study is to develop a reduced order model for the system by considering the most important physical phenomena of aerodynamics and structural dynamics. Moreover, the behavior of the system can be influenced by the coupled dynamics between the tower motions and the blade pitch and turbine speed which can cause instabilities in the control loops in the worst case. By using a suitable wavelet funcation, called Haar functions, a recursive computational procedure is established for finding the system dynamics approximately by solving only alg…

MECHANISM DESIGN FOR OPTIMAL CONSENSUS PROBLEMS

2006

We consider stationary consensus protocols for networks of dynamic agents with fixed and switching topologies. At each time instant, each agent knows only its and its neighbors’ state, but must reach consensus on a group decision value that is function of all the agents’ initial state.We show that our protocol design is the solution of individual optimizations performed by the agents. This notion suggests a game theoretic interpretation of consensus problems as mechanism design problems. Under this perspective a supervisor entails the agents to reach a consensus by imposing individual objectives. We prove that such objectives can be chosen so that rational agents have a unique optimal proto…

Scenario of the Birth of Hidden Attractors in the Chua Circuit

2017

Recently it was shown that in the dynamical model of Chua circuit both the classical selfexcited and hidden chaotic attractors can be found. In this paper the dynamics of the Chua circuit is revisited. The scenario of the chaotic dynamics development and the birth of selfexcited and hidden attractors is studied. It is shown a pitchfork bifurcation in which a pair of symmetric attractors coexists and merges into one symmetric attractor through an attractormerging bifurcation and a splitting of a single attractor into two attractors. The scenario relating the subcritical Hopf bifurcation near equilibrium points and the birth of hidden attractors is discussed.

A four-node MITC finite element for magneto-electro-elastic multilayered plates

2013

An isoparametric four-node finite element for multilayered magneto-electro-elastic plates analysis is presented. It is based on an equivalent single-layer model, which assumes the first order shear deformation theory and quasi-static behavior for the electric and magnetic fields. First, the electro-magnetic state of the plate is determined in terms of the mechanical primary variables, namely the generalized displacements, by solving the strong form of the magneto-electric governing equations coupled with the electro-magnetic interface continuity conditions and the external boundary conditions. In turn, this result is used into the layers constitutive law to infer the equivalent single-layer…

A finite element formulation for large deflection of multilayered magneto-electro-elastic plates

2014

An original finite element formulation for the analysis of large deflections in magneto-electro-elastic multilayered plates is presented. The formulation is based on an equivalent single-layer model in which first order shear deformation theory with von Karman strains and quasi-static behavior for the electric and magnetic fields are assumed. To obtain the plate model, the electro-magnetic state is firstly determined and condensed to the mechanical primary variables, namely the generalized displacements. In turn, this result is used to obtain laminate effective stiffness coefficients that allow to express the plate mechanical stress resultants in terms of the generalized displacements and a…

La Media Education a scuola. I primi risultati di una ricerca nelle scuole statali palermitane

2008

A MILANKOVITCH CLIMATE CONTROL ON THE MIDDLE MIOCENE MEDITERRANEAN INTERMEDIATE WATER.

2004

The marly sediments of the Blue Clay Formation in the upper part of the Middle Miocene Ras il-Pellegrin composite section (Malta island, central Mediterranean) have been investigated by integrated analysis of benthic microfauna and planktonic and benthic oxygen isotopes. The astronomical calibration of the whole section, obtained by using the astronomical solution of Laskar et al. (1993), indicates for deposition of the analysed sediments a time interval ranging between 13.75 and 12.32 Ma (Sprovieri et al., 2002). This time interval is useful to investigate the oceanographic evolution of the (paleo)Mediterranean after the interruption of communications between the Mediterranean and Indo-Pac…

Word search sequences in teacher-student interaction in an English as medium of instruction context

2019

This study explores the ways students in a higher education setting engage in word searches. The investigation draws on 30-hour video recordings of content classes in an English as a medium of instruction university in Turkey. Using conversation analysis, the study focuses on the interactionally accomplished functions of vocal and visual practices deployed by the students in the course of a word search. We revealed that word searches are constructed through publicly visible resources (i.e. gaze, body orientation, gestures) and explicit formulaic expressions (i.e. how can I say it?), and accomplished via bilingual resources. It was also observed that the teacher does not orient to word searc…

Melodic and contextual similarity of folk song phrases

2007

Various models of melodic similarity have been proposed and assessed in perceptual experiments. Contour and pitch content variables haven been favoured although music-theoretical and statistical variables have also been claimed to explain similarity ratings. A Re-analysis of earlier work by Rosner & Meyer (1986) suggests that simple contextual features can also be highly explanatory with more complex stimuli. A new experiment containing short melodic phrases investigated the effectiveness of several global and comparative variables. A multi-dimensional scaling solution indicated that both melodic direction and pitch range are highly relevant for making such similarity judgments and tha…