We propose an efficient Verifiable Ring Encryption (VRE) for ad hoc groups. VRE is a kind of verifiable encryption [16,1,4,2,8] in which it can be publicly verified that there exists at least one user, out of a designated group of n users, who can decrypt the encrypted message, while the semantic security of the message and the anonymity of the actual decryptor can be maintained. This concept w...

The present work approaches the problem of achieving the approximate solution of the second order initial value problems (IVPs) via its conversion into a Volterra integral equation of the second kind (VIE2). Therefore, we initially solve the IVPs using Runge–Kutta of the forth–order method (RK), and then convert it into VIE2, and apply the εmodified block–pulse functions (εMBPFs) and their oper...

Brain-Computer interface systems are a new mode of communication which provides a new path between brain and its surrounding by processing EEG signals measured in different mental states.  Therefore, choosing suitable features is demanded for a good BCI communication. In this regard, one of the points to be considered is feature vector dimensionality. We present a method of feature reduction us...

‎In this paper, we investigate the chaotic behaviors of the fractional-order permanent magnet synchronous motor (PMSM) system. The necessary condition for the existence of chaos in the fractional-order PMSM system is deduced and an active controller is developed based on the stability theory for fractional systems. The presented control scheme  is simple and flexible, and it is suitable both fo...

In this paper, we consider a second-order singularly perturbed differential-difference equations with mixed delay and advance parameters. At first, we approximate the model problem by an upwind finite difference scheme on a Shishkin mesh. We know that the upwind scheme is stable and its solution is oscillation free, but it gives lower order of accuracy. So, to increase the convergence, we propo...

the study of flight vehicle structures reveals the importance of obtaining the most suitable accuracy compatible with construction. for this purpose, several experiments were conducted at the agard institute. in this paper the results of one such experiment performed on a sample airplane wing are presented. aircraft structural engineers use several methods to model these structures. specifing h...