Sharif Digital Repository

Naturalness in Text-to-Speech (TTS) systems is very important in achieving high quality waveform. The naturalness of the waveform is highly correlated to phonetic coverage and prosodic features such as loudness, duration and pitch. This paper addresses the implementation of a prosodic TTS for Azeri. The TTS system to which the prosodic information is added, is a concatenative synthesizer based on diphones. For adding prosody and increasing naturalness, we have obtained a primary pitch curve for each word, based on the location of the stressed syllable. Also using sentence type effects, the final pitch contour has been modified. As far as we know, the output speech that is produced with this... 

Effects of fringing electrostatic fields on the behavior of a double clamped initially curved microbeam are investigated. Galerkin's decomposition method is applied on the governing Euler-Bernoulli equation with distributed electrostatic force to obtain the lumped-parameter model of the system. The resulting single degree of freedom model is obtained with the Palmer's formula as a model for the fringing field effects. To derive an applied form of the fringing field effect in lumped model, we have used Genetic Algorithms as an optimization method. Then using the lumped model, we have investigated the system nonlinear dynamics. Comparison of the obtained bifurcation diagrams with the... 

This paper presents an attempt to control the chaotic behavior of Rayleigh-Bénard convection system in weakly elastic fluids. In this article, a nonlinear model is presented which fundamentally refers to a model introduced by Khayat. The nonlinear model has chaotic behavior which is controlled by using sliding mode method. In the presence of uncertainty for some parameters of the model, a controller is designed to stabilize the dynamic of the system on the desired trajectory. Different simulation results are presented to demonstrate the effectiveness of the designed controller in tracking different desired trajectories. ©2009 IEEE  

Dynamic behavior of a electrostatically actuated MEMS resonator is investigated. A double clamped micro-beam under distributed DC and AC actuation is used. Corresponding single degree of freedom model is derived using Galerkin's decomposition method. Homotopy Perturbation Method (HPM) is implemented in order to derive analytical expression for frequency response of the micro-resonator. Comparison of the obtained results with the numerical simulations confirms that HPM agrees very well with numerical simulations for a wide range of parameters. Obtained analytical solution can be used for design and optimization of MEMS resonators  

This paper deals with the dynamic analysis of a delaminated composite beam under the action of moving oscillatory mass. The beam is analyzed as four interconnected sub-beams using the delamination limits as their boundaries. The constrained model is used to model the delamination region. The continuity and equilibrium conditions are satisfied between the adjoining beams. The beam response variation due to the delamination with respect to the intact beam has been investigated. Furthermore, the possible separation of the moving oscillator from the beam during the course of the motion is investigated by monitoring the contact force between the oscillator and the beam. The effect of the... 

In this paper, nonlinear oscillation of a pendulum wrapping and unwrapping around two cylindrical bases is studied and an analytical solution is obtained using multiple scales method. Equations of motion are derived based on energy conservation technique. Applying perturbation method on the equations, nonlinear natural frequency of the system is calculated along with its time response. Analytical results are compared with numerical findings and good agreement is found. Effect of nonlinearity due to large amplitude and radius of cylinders on the system frequency is evaluated. Results indicate that as the radius of cylinder is increased, nonlinear frequency is enhanced. Initial amplitude plays... 

In this paper, nonlinear vibration of a micro cantilever exposed to a constant velocity flow is studied. In order to obtain vibration frequency and time response of the micro beam the variational iteration method is used as a novel tool for solving nonlinear differential equations. Results of the analytical solution are compared with those obtained by Runge-Kutta method which shows very good agreement between them. Results confirm that frequency of vibration depends on the flow velocity. Also, the high sensitivity of the vibration frequency to the flow velocity means that it can be an effective indicator of velocity  

Due to the nonlinear dynamics of hydraulic systems, applying high performance closed-loop controllers is complicated. In this paper, a single-rod hydraulic actuator is considered in which load displacement (for positioning purposes) is controlled via manipulation of the input voltage to the servo-valve. Dynamics of the servo-valve is described by first and second order transfer functions (named as Models 1 and 2). Through linearization of the system around its operating points, dynamics of the hydraulic actuator is represented in the state space. A full-order observer is designed for on-line states estimation. Then, feedback control system is designed for both regulation and tracking... 

The accuracy of multi dimensional simulation of vehicle dynamics has been significantly increased for both passive and active vehicles which are equipped with advanced electronic components. Recently, one of the subjects that has been considered is increasing the car safety in design. Therefore, many efforts have been done to increase vehicle stability especially during the turn. It is also very important in three wheel car. One of the most important efforts is adjusting the camber angle in the car suspension system. Camber angle as well as the vehicle stability has major effects on the wheel slip, reducing rubber abrasion, acceleration and braking. Since the increase or decrease in the... 

An integrated procedure for mathematical modeling and power control balance for a SPA (Split Parallel Architecture) hydraulic hybrid vehicle is presented in this paper. Dynamic mathematical model of the powertrain is constructed firstly, which includes five modules: diesel engine, traction motor, starter, loading pump and accumulator. Based on the mathematic model of control modes a stability analysis is done. For some control modes a Sliding Mode Control is designed, which uses full-states closed-loop feedback. The paper finally illustrates and discusses the results of simulation. The results show that the performance and stability of control modes are proper and a power control strategy... 

The proposed current harmonic model for high-power synchronous machines is dependent on the inductances of quadrature and direct axes. Variation of these parameters, as a consequence of modification in operating point, aging and temperature rise, in-progress pulse patterns, are no longer optimal solutions for minimization of harmonic losses. On the other hand, offline calculation of optimal pulse patterns for slight changes in these parameters, and storing them in read-only memories to serve as look-up tables, give rise to immoderate computational burden and unmanageable look-up tables. Notwithstanding performing online identification process and offline calculation of optimal pulse... 

In this paper a linear delayed feedback control is proposed and experimentally applied to eliminate chaos in a nonlinear electrical circuit which is known as Sprott circuit. The chaotic behavior of the system is suppressed by stabilizing one of its first order Unstable Periodic Orbits (UPOs) by a controller designed based on so-called Pyragas method. The effectiveness of this method, firstly, is numerically investigated by stabilizing the unstable first order periodic orbit and then verified experimentally by a laboratory setup. ©2007 IEEE  

Cooperative systems have been extensively investigated in literature. Herein the criteria and implementation for finding the optimal configuration of the Dual-Arm Cam-Lock (DACL) robot manipulators at a specific point with the objective to optimize the applicable task-space force in a desired direction are addressed. The DACL robot manipulators are reconfigurable arms formed by two parallel cooperative manipulators. Some of their joints may lock into each other. Therefore, the arms normally operate redundantly. However, when higher structural stiffness is needed these two arms can lock into each other in specific joints and loose some degrees of freedom. The dynamics of the DACL robot is... 

In the present work, a multi sensing grasper has been developed for minimally invasive surgery with embedded ZnO piezoelectric and Fiber Bragg Grating sensors. In this model, a sensing patch equipped with three FBG sensors to sense the temperature in rage of 800 n.m and two separated FBG in range of 1550 m.m to detect the displacement in x and y directions. ZnO piezoelectric is highly sensitive to time and provides a good resistance to temperature. Therefore, this sensor is used for measuring the rate of strain and creep coefficient. A finite element approach based on the viscous material theory and plane displacement theory of anisotropic materials has been utilized to obtain the compliance...