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In this paper, the trajectory tracking problem for a wheeled mobile robot in the presence of kinematic and dynamic uncertainties is considered. A nonlinear control approach based on lyapunove stability theory is proposed for this problem. Uncertainties are modeled as lumped disturbances and are estimated by a generalized disturbance observer using Linear Matrix Inequalities(LMI). These estimates are used for control laws design for compensating disturbances. Simulation results show the effectiveness of the proposed method in the presence of uncertainties generated by sliding velocity.

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Recently, Routing in Vehicular Ad hoc Networks (VANETs) has found significant attention due to its unique characteristics such as lack of energy constraints and high-speed vehicles. In addition, since VANET networks are highly dynamic, design of routing algorithms suitable for an urban environment could be extremely challenging. Appropriate algorithms for urban environments should be opportunistic routing (OR) algorithms in which traffic transmission is performed using the store-carry-forward mechanism. Most of the OR algorithms use the flooding mechanism for increasing delivery ratio without considering the overheads of flooding. In this paper, a new algorithm called Reliability-aware Location and History based Opportunistic Routing (RLHOR) is proposed to reduce overhead of message replication . The RLHOR searches for the most reliable route by evaluating the reliability of intermediate links considering their lifetimes, location and direction of intermediate vehicles, and the history of message delivery by intermediate vehicles. Using the ONE simulator, our performance evaluation results show that the RLHOR can operate better than other conventional OR algorithms under different network scenarios. Under sparse networks, the RLHOR not only increases delivery ratio, but also reduces overhead and traffic loss.

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Conventional Off-Line (50-60Hz) light emitting diode (LED) drivers usually need an electrolytic capacitor to reduce power imbalance between ac input and dc output, and to decrease the low-frequency component of the output ripple. However, electrolytic capacitor is the key component which limits the lifespan of LED driver. If a driver uses a pulsating output current, the electrolytic capacitor can be omitted. This paper proposes a high power factor LED driver with high frequency pulsating driving current, in which electrolytic capacitor has omitted from the topology. The driver has two outputs that allow the number of driving LEDs to increase, an LED string will be connected to each output and a single switch is used in series with each LED string, thus the number of switches is equal to the number of outputs. Output and Storage capacitor voltages are sensed and used to implement the control method to regulate the output current. Low cost and high efficiency can be obtained due to the power structure and the proposed control method. Simulations, calculations and experimental results are provided for the proposed circuit.

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The modeling of high frequency electromagnetic transients and the simulation of the voltage and the current distribution in the multi-winding traction transformer's windings due to these transient waves are very important. In the present article, in addition of presenting finite element models, the coupled field-circuit approach is proposed for the modeling of high frequency electromagnetic transients in a multi-winding traction transformer. The proposed method uses two-dimensional finite element models coupled with an external circuit to model the electromagnetic transient behavior of the multi-winding traction transformer. Afterwards, the results of the presented method have been compared with the results obtained from a complete three-dimensional finite element model as well as the detail model's results and the results are validated. Finally, the validated high-frequency model has been used to study the impulse response of the transformer. As shown, the proposed approach is a simple and fast method, and also has good accuracy in modeling of the impulse voltage distribution in the multi-winding traction transformer's windings.