The purpose of this article is to develop a multicriteria group decision making (MCGDM) method in dual hesitant fuzzy (DHF) environment by evaluating the weights of the decision makers from the decision matrices using two newly defined prioritized aggregation operators based on score function to remove the inconsistencies in choosing the best alternative. Prioritized weighted averaging operator and prioritized weighted geometric operator based on Einstein operations are described first for aggregating DHF information. Some of their desirable properties are also investigated in details. A method for finding the rank of alternatives in MCGDM problems with DHF information based on priority levels of decision makers is developed. An illustrative example concerning MCGDM problem is considered to establish the application potentiality of the proposed approach. The method is efficient enough to solve different real life MCGDM problems having DHF information.
In wireless mobile networks, a client can move between different locations while staying connected to the network and access the remote server over the mobile networks by using their mobile de- vices at anytime and anywhere. However, the wireless network is more prone to some security attacks, as it does not have the ingrained physical security like wired networks. Thus, the client authentication is required while accessing the remote server through wireless network. Based on elliptic curve cryptosystem (ECC) and identity-based cryptography (IBC), Debiao et al. proposed an ID-based client authentication with key agreement scheme to reduce the computation and communication loads on the mobile devices. The scheme is suitable for mobile client-server environments, is secure against different attacks and provides mutual authentication with session key agreement between a client and the remote server as they claimed. Unfotunately, this paper demonstrates that Debiao et al.’s scheme is vulnerable some cryptographic attacks, and proposed an improved ID-based client authentication with key agreement scheme using ECC. The proposed scheme is secure based on Elliptic Curve Discrete Logarithm Problem (ECDLP) and Computational Diffie-Helmann Problem (CDHP). The detail analysis shows that our scheme overcomes the drawbacks of Debiao et al.’s scheme and achieves more functionality for the client authentication with lesser computational cost than other schemes.
The microscale deformation behaviour of the Al-4.5Cu-2Mg alloy has been studied to understand the influence of various processing routes and conditions, i.e. the gravity casting with and without grain refiner, the rheocast process and the strain induced melt activation (SIMA) process. The micromechanics based simulations have been carried out on the optical microstructures of the alloy by 2D representative volume elements (RVEs) employing two different boundary conditions. Microstructural morphology, such as the grain size, the shape and the volume fraction of α-Al and binary eutectic phases have a significant effect on the stress and strain distribution and the plastic strain localization of the alloy. It is found that the stress and strain distribution became more uniform with increasing the globularity of the α-Al grain and the α-Al phase volume fraction. The simulated RVEs also reveals that the eutectic phase carries more load, but least ductility with respect to the α-Al phase. The SIMA processed alloy contains more uniform stress distribution with less stress localization which ensures better mechanical property than the gravity cast, grain refined and rheocast alloy.