No abstract

As a defense technology with endogenous security, mimic defense plays an important role in network security research. The scheduling of executors is one of the severe problems to take into account for mimic defense, and current research lacks comprehensive consideration of the influence of system architecture and attack behavior on scheduling algorithm. Based on previous research, this paper first introduces concept of heterogeneity and confidence according to vulnerability attributes and attack distribution characteristics to characterize the executors. Moreover, the TOPSIS (Technique for Order Preference by Similarity to an Ideal Solution) algorithm is brought in to optimize the system security and improve operating efficiency. Experimental results showed that,compared with the existing algorithms, Random, MD, RSMS, it improves the security of the system in non-uniform distributed attack scenario and the operating efficiency in each attack scenario.

This paper focused on PSL (peak sidelobe level) reduction for subarrayed beam scanning in phased array radars. The desired GSP (Gaussian Subarray Patterns) are achieved by creating a subarray weighting network. The GSP-based method could reduce PSL of array pattern; compared with the method based on the desired subarray pattern which is defined by ideal space-domain filter, the PSL reduction performance is improved remarkably. Further, based on the concept adopting superelement patterns to approximately express original subarray patterns, the simplified GSP-based method is proposed. So the dimension of each matrix required for creating the weighting network, which was originally the same as the element number, could be reduced to the same as the subarray number. Consequently, we achieve remarkable reduction of the computation burden; simultaneously, the PSL mitigation performance is degraded slightly. Simulation results demonstrate the validity of the introduced methods.

In modern complex battlefield environment, it is important to obtain the frequency spectrum precisely. We propose an operational method of instantaneous frequency measurement (IFM) assisted by photonics, which can achieve high precision based on stimulated Brillouin scattering (SBS), giving the credit to the narrow linewidth of gain spectrum of SBS. We use MZM and DPMZM cascade to generate a tunable continuous optical signal and modulate the measured signal to the continuous optical signal and a DPMZM is used to generate pump light, the two beams of light are injected into the fiber, the stimulated Brillouin scattering (SBS) effect occurs in the optical fiber and the Brillouin gain spectrum (BGS) is formed. By setting the scanning frequency, the Brillouin gain varies with frequency and the amplitude comparison function (ACF) can be formed in the narrow line band of BGS. And the measurement of full frequency band is realized through a reference signal, the measured frequency range is limited only by photoelectric device. Estimation of multiple radio-frequency (RF) signals can also be achieved with a resolution of 250 MHz. In the numerical simulation, the average measurement error less than 1 MHz is achieved in this scheme.

In this paper we present a study of the of the steady state analysis of a Solid Oxide Fuel Cell Performance. We compare standard gas channels for air feeds to the same model with a porous channel for the air feed. The increased time constant on the air side has the potential to increase the efficiency of the SOFC. The current density, along the electrolyte, the oxygen concentration in the gas channel and the porous cathode, and the potential in the cathode and the electrolyte are compared for the two models. All the simulations are treated at isothermal conditions and applied using COMSOL software.