RESUMEN
Evidence supports that music can modulate many physiological roles, exerting clear effects on the central nervous system. For this effect to be positive, music should be tuned at a frequency of 432 Hz. This study aims to determine the effects of prenatal exposure to music on reflexive motor behaviors in mice offspring. Six pregnant female NMRI mice (8-10 weeks old) were randomly and equally allocated into two groups. Group 1 as control was placed in a normal housing area (average room noise 35 dB), and Group 2 was exposed to music pitched at 432 Hz for 2 h a day played at constant volume (75/80 dB) during pregnancy. Following delivery, four pups from each pregnant mouse were selected, and reflexive motor behaviors including ambulation, hind-limb foot angle, surface righting, grip strength, front- and hind-limb suspension, and negative geotaxis were determined. Based on the findings, prenatal exposure to music significantly increased ambulation score, grip strength, and front- and hind-limb suspension compared to the control group (P < 0.05). Also, prenatal exposure to music significantly decreased hind-limb foot angle, negative geotaxis, and surface righting compared to the control group (P < 0.05). These results suggested that music exposure during pregnancy had a significant positive effect on all tested reflexive motor behaviors in mice offspring.
RESUMEN
In this research, a model-free control strategy for vibration suppression of base-isolated structures, which are excited by an earthquake, is investigated. For this purpose, the semi-active base isolated system including a magnetorheological (MR) damper is utilized. In this way, the displacement of the base isolator is measured by a linear variable differential transformer (LVDT). Accordingly, an adaptive fuzzy sliding mode observer is implemented to estimate the vector of state tracking error. This estimated vector is then employed by an adaptive fuzzy sliding mode control scheme to calculate the input voltage of the MR damper. The efficiency of the implemented model-free control strategy is studied by some numerical simulations. The advantages of the proposed controller can be summarized as its flexibility and robustness against disturbance rejection and model uncertainty.
RESUMEN
In this research, the robust control of uncertain linear Internet-based systems has been studied. In this way, an event-triggered strategy has been used to reduce the amount of communication between the plant and the remote controller. The proposed control strategy also ensures stability, robustness and output tracking against the model uncertainties and communication network negative effects. For this purpose, a new sliding surface is designed for linear Internet-based systems by solving a set of linear matrix inequalities which is achieved using the Lyapunov's stability theorem. Accordingly, corresponding to a range of expected time delays, a discrete-time sliding mode control method is used to design some control signals. The proposed method can cope with relatively large network delays and packet dropouts. The asymptotic stability and robustness of the closed-loop system are also evaluated. Simulation studies on four well-known benchmark problems demonstrate the effectiveness of the proposed method with respect to the model uncertainty and also band-limited communication networks.
RESUMEN
This paper presents a variable selective control methodology for control of networked systems subject to transfer delay, packet-loss and packet-disordering. This approach is based upon the extension of the variable sampling period idea with a new packet based control methodology. In this way, corresponding to a range of expected time delays, a number of step-invariant discrete-time plant models are considered and based on them, a switching observer-based controller is designed by solving linear matrix inequalities (LMIs). A sufficient condition for closed-loop asymptotic stability is derived. Simulation and experimental investigations demonstrate the effectiveness of the proposed method in the real world.
