This paper proposes a robust position control scheme for a quadrotor UAV system under uncertainties. The proposed control algorithms combine integral sliding mode and backstepping sliding mode controllers in a double-loop control structure (i.e., inner-outer loop control). The design of the proposed controller is divided into two subcontrollers, namely, attitude and position controllers for the quadrotor. In this work, a nonsimplified six-degree-of-freedom quadrotor model is first established in the presence of disturbances. Afterward, we develop a robust backstepping sliding mode controller for the attitude control of the quadrotor. Next, a robust integral sliding mode controller is designed for the outer loop of the quadrotor to ensure the position trajectory tracking capability in the presence of disturbances. The stability and performance of the quadrotor is thoroughly investigated using Lyapunov stability analysis. Numerical simulations demonstrate the effectiveness of the developed solutions for a quadrotor.

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The automobile companies are focusing on recent technologies such as growing Hydrogen (H2) and Fuel Cell (FC) Vehicular Power Train (VPT) to improve the Tank-To-Wheel (TTW) efficiency. Benefits, the lower cost, 'Eco' friendly, zero-emission and high-power capacity, etc. In the power train of fuel cell vehicles, the DC-DC power converters play a vital role to boost the fuel cell stack voltage. Hence, satisfy the demand of the motor and transmission in the vehicles. Several DC-DC converter topologies have proposed for various vehicular applications like fuel cell, battery, and renewable energy fed hybrid vehicles etc. Most cases, the DC-DC power converters are viable and cost-effective solutions for FC-VPT with reduced size and increased efficiency. This article describes the state-of-the-art in unidirectional nonisolated DC-DC Multistage Power Converter (MPC) topologies for FC-VPT application. The paper presented the comprehensive review, comparison of different topologies and stated the suitability for different vehicular applications. This article also discusses the DC-DC MPC applications more specific to the power train of a small vehicle to large vehicles (bus, trucks etc.). Further, the advantages and disadvantages pointed out with the prominent features for converters. Finally, the classification of the DC-DC converters, its challenges, and applications for FC technology is presented in the review article as stateof-the-art in research.

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The recent advancement in wireless body area networks (WBAN) plays an important role in remote health care systems. However, these networks are suffering from data security and privacy threats. Lack of anonymous authentication and secure data communication leads to operation failure in WBAN. Computational cost and privacy preservation are the two major hindrances for anonymous authentication in many existing schemes. Therefore, a secure and efficient privacy-preserving anonymous authentication scheme is proposed to provide data security and privacy to the users with low computational and communication cost. The performance analysis and experimental simulation results ensure that our proposed anonymous authentication method outperforms the existing systems in terms of providing data security and privacy with less computational overhead.