Calculation of the B_{c}leptonic decay constant using the shifted N-expansion method

We give a review and present a comprehensive calculation for the leptonic constant B_{c} of the low-lying pseudoscalar and vector states of B_{c}-meson in the framework of static and QCD-motivated nonrelativistic potential models taking into account the one-loop and two-loop QCD corrections in the short distance coefficient that governs the leptonic constant of $B_{c}$ quarkonium system. Further, we use the scaling relation to predict the leptonic constant of the nS-states of the (b_bar)c system. Our results are compared with other models to gauge the reliability of the predictions and point out differences.Comment: 26 page

QoS-based mobility system for autonomous unmanned aerial vehicles wireless networks

In the era of the Unmanned Aerial Vehicles (UAVs) several kinds of applications were born to make use of these autonomous vehicles, from surveillance to emergency management, from entertainment to package delivery. All these systems are based on the autonomous capability of the unmanned vehicles. The common factor of such systems is the use of an ad-hoc wireless network that enables the communication among the vehicles. However, guaranteeing an effective level of Quality-of-Service in the UAVs wireless network is hard to reach because of the unpredictable nature of such a system. Multiple solutions have emerged to address this problem, like enhanced communication protocols or mobility control systems that exploit the autonomous mobility of such vehicles. Nevertheless, none of those solutions have real affect on the end-to-end QoS performance. This paper aims to address the issue of guaranteeing the wireless network connectivity while providing Quality-of-Service at network layer, i.e., the proposed system will dynamically adapt its topology in order to increase the end-to-end network performance by using nature-inspired algorithm

Improving Key Negotiation in Transitory Master Key Schemes for Wireless Sensor Networks

In recent years, wireless sensor networks have been adopted in different areas of daily life, exposing the network data and the hardware to different security threats. Many key management schemes have been proposed aiming at securing the communications among nodes, for instance the popular LEAP+ protocol. This paper proposes an enhanced variant of the LEAP+ protocol that decreases the key setup time through the reduction of the number of exchanged packets thus improving the security of communications. The results extracted from extensive test sessions obtained by network simulation have been compared to the corresponding data derived from the LEAP+ protocol in order to quantify the improvements