Xidian University

About: Xidian University is a education organization based out in Xi'an, China. It is known for research contribution in the topics: Antenna (radio) & Computer science. The organization has 32099 authors who have published 38961 publications receiving 431820 citations. The organization is also known as: University of Electronic Science and Technology at Xi'an & Xīān Diànzǐ Kējì Dàxué.

Anomaly intrusion detection method based on HMM

Abstract: An anomaly intrusion detection method based on HMM is presented. The system call trace of a UNIX privileged process is passed to a HMM to obtain state transition sequences. Preliminary experiments prove the state transition sequences can express the different mode between normal action and intrusion behaviour in a more stable and simple manner.

Globally Stable Adaptive Backstepping Neural Network Control for Uncertain Strict-Feedback Systems With Tracking Accuracy Known a Priori

Abstract: This paper addresses the problem of globally stable direct adaptive backstepping neural network (NN) tracking control design for a class of uncertain strict-feedback systems under the assumption that the accuracy of the ultimate tracking error is given a priori . In contrast to the classical adaptive backstepping NN control schemes, this paper analyzes the convergence of the tracking error using Barbalat’s Lemma via some nonnegative functions rather than the positive-definite Lyapunov functions. Thus, the accuracy of the ultimate tracking error can be determined and adjusted accurately a priori , and the closed-loop system is guaranteed to be globally uniformly ultimately bounded. The main technical novelty is to construct three new $n$ th-order continuously differentiable functions, which are used to design the control law, the virtual control variables, and the adaptive laws. Finally, two simulation examples are given to illustrate the effectiveness and advantages of the proposed control method.

On the equivalence of McEliece's and Niederreiter's public-key cryptosystems

Abstract: It is shown that McEliece's and Niederreiter's public-key cryptosystems are equivalent when set up for corresponding choices of parameters. A security analysis for the two systems based on this equivalence observation, is presented. >

Study of WO3-based sensing materials for NH3 and NO detection

Abstract: Gas sensing materials of WO3 loaded with 1 wt.% metal oxides were prepared and applied for NH3 and NO detection. The measurement of NH3 and NO sensing properties of the materials revealed that WO3+1 wt.% Mg, WO3+1 wt.% Zn, WO3+1 wt.% Mo and WO3+1 wt.% Re characterized good responses to NH3 and NO. As a whole, these materials have low resistance, high sensitivity and fast response to NH3 and NO compared with pure WO3. The possibility of NH3–NO equivalent point sensor was discussed. It can be used for real time monitoring, and controlling the reduction of NO using NH3.

Screening-photovoltaic spatial solitons in biased photovoltaic–photorefractive crystals and their self-deflection

Abstract: Steady-state dark (or bright) spatial solitons are predicted for biased photovoltaic–photorefractive materials when the diffraction of an optical beam is exactly compensated for by nonlinear self-defocusing (or self-focusing) that is due both to the photovoltaic effect and to spatially nonuniform screening of the applied field. These solitons differ from previously observed steady-state photorefractive or photovoltaic spatial solitons in their properties and experimental condition. These biased photovoltaic solitons are known as the screening-photovoltaic solitons. If the bias field is much stronger than the photovoltaic field, then the screening-photovoltaic solitons are just like the screening solitons. If the applied field is absent, they degenerate into photovoltaic solitons in the closed-circuit condition. We investigate the self-deflection process of bright screening-photovoltaic solitons by taking diffusion effects into account. By use of perturbation techniques it is found that the center of the optical beam moves on a parabolic trajectory and, moreover, that the central spatial-frequency component shifts linearly with the propagation distance. Both the spatial deflection and the angular deviation are proportional to the sum of two dimensionless quantities that are associated with the bias field and the photovoltaic field, respectively. The drift process and the photovoltaic process play an equivalent role in the self-bending process.