One of the most important issues in capital market is to explain the price volatilities by fundamental models. In two recent decades, some adjustments were explored to improve the explanatory ability of models.For instance, bubble component is introduced to increase the ability to explain the price volatilities.In this paper, bubble prices are introduced with specific definitions and mathematical relations, then, the reasons for emergence of bubble price of securities are analyzed from the behavioral point of view.The bubble is an unobservable variable, which is obtained from State-Space form and Kalman Filter on current prices. Then, the effectiveness of herding behavior, fad tendency and psychological conditions on bubble are investigated.The empirical results indicate that bubble price in Tehran Stock Exchange Market is affected by herding behavior, fad tendency and psychological conditions.

In this study first, we investigated the equations in movement of an underwater robot and also the State-Space model of system is expressed with linearizing existing equations. Then, an energy efficient path is planned using dynamic equations and dynamic planning optimization method. There are moving obstacles in environment in which a robot is moving. It can be seen that the planned path is flat and energy consumption is minimized. The main objective of the study is to present an appropriate controller for the provided State-Space model of system. For this purpose, by studying the system controller designing using LQR optimal controller, an appropriate controller for model has been presented. The planning a path to a target for the underwater robot has been presented using combination of optimization algorithm with learning automata and the krill herd optimization algorithm. In other words, the study has applied hybrid algorithm in order to find optimal path for the underwater robot to move in a static environment which is expressed through the map with the nodes and links.

In this paper, robust vibration control of a thin functionally graded beam with a variable cross-section has been investigated. For this purpose, piezoelectric patches are used as sensors to measure the displacement of the beam and as actuators to apply control forces. In this way, firstly, Euler-Bernoulli theory is used to derive the governing dynamical partial differential equation, through the Hamilton’s principle. Approximate solution of these equations is achieved using finite difference method, and the proper orthogonal decomposition is then used to obtain vibration mode shapes. After that, time-dependent ordinary differential equations are attained using Galerkin projection scheme and then represented in the statespace form. Since the data measurement is done in sampling intervals, the system is considered as sampleddata. In this way, direct digital control design methodology is used. For this purpose, based on its zero-order hold equivalent model, a robust discrete-time, observer-based, output feedback controller is designed. In this regard, controller and observer gains are designed by a Lyapunov-based method. This procedure is done by solving a set of linear matrix inequalities. Simulation studies show the effectiveness of the proposed method.

In this paper, the effects of supersonic flutter and moving load are studied simultaneously on a honeycomb sandwich beam with a cermet covered layer. The core layer ratio is considered as a regular nomex honeycomb which has the high stiffness to weight ratio. Also cermet layer which has a high thermal strength is considered as aluminum oxide in mild steel matrix, for optimized fractional ceramic concentration. The structural formulation is based on the classical Euler-Bernoulli beam theory and the quasi-steady first order supersonic piston theory is employed to describe the aerodynamic loading. Hamilton’ s principle in conjunction with the generalized Fourier expansions and Galerkin method are used to develop the dynamical model of the structural systems in the statespace domain. The critical dynamic pressures are obtained by p method for a honeycomb sandwich beam. Simulation results shows that using cermet layer as a constrained layer has an important role in postponding the flutter to higher dynamic pressures compared to the same sandwich layer with aluminum constrained layer. The thickness effect of cermet layer on flutter phenomena is also considered. Finally, in order to obtain efficeient operational results, the aeroelastic responses of honeycomb sandwich beam in supersonic regime under moving loads with different velocities are calculated.