Vol 50, No 1 (2016)

In this study we carried out the analysis of the time resolution of Josephson balanced comparators with Bloch inductance. It was obtained expression for time resolution in case of growing strobe-pulse of voltage. It is shown that, time resolution is determined by Bloch inductance of small size Josephson junctions. Estimation gives the time resolution at the level subpicosecond.

The influence of thermal hysteresis of the comparator on the sensitivity of signal converter and distortions of the zero line at various comparator type equivalent time signal conversion methods is studied. The research is carried out by statistical simulations and physical experiments. In the simulations two sets of parameters of the thermal hysteresis are used: one appropriate to parameters of experimental device, and the second—appropriate to comparator with a stronger thermal hysteresis.

A network constructed according to the IMS architecture consists of different modules that sequentially process signaling messages transferred during providing communication services. Delays that occur when processing signaling messages determine the quality of service for subscribers. International recommendations define the quality-of-service metrics, which include not only the mean, but also the 95% quantile. The paper proposes an approach to analyzing the quality-of-service characteristics. It is assumed that IMS-network nodes work as multi-server queues with general service time distribution.

Supervisory Control and Data Acquisition (SCADA) systems are widely used in critical infrastructures such as water distribution networks, electricity generation and distribution plants, oil refineries, nuclear plants, and public transportation systems. However, the increased use of standard protocols and interconnectivity has exposed SCADA systems for potential cyber-attacks. In recent years, the cyber-security of SCADA systems has become a hot issue for governments, industrial sectors and academic community. Recently some security solutions have been proposed to secure SCADA systems. However, due to the critical nature of SCADA systems, evaluation of such proposed solutions on real system is im-practical. In this paper, we proposed an easily scalable and reconfigurable virtual SCADA security testbed, which can be used for developing and evaluating SCADA specific security solutions. With Distributed Denial of Service (DDoS) and false data injection attack scenarios, we demonstrated how attackers could disrupt the normal operation of SCADA systems. Experimental results show that, the pro-posed testbed can be effectively used for cyber security assessment and vulner-ability investigation on SCADA systems. One of the outcomes of this work is a labeled dataset, which can be used by researchers in the area of SCADA security.