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For the miniaturization of two-dimensional autocollimator, a method of using embedded measurement system instead of special host computer is presented. This system integrates CMOS image sensor's driving circuit, frame processing, adaptive exposure control, centroid subdivision and localization of cross, misalignment angle calculation, display driver and other functions within a FPGA chip, and the...
A session-based admission time ratio (ATR) feedback control mechanism is introduced in order to the control Internet load pressure. An auto-regressive moving average (CARIMA) system is described as the Internet load pressure model. The Model Reference Adaptive Controller (MRAC) based on feedback control and feedforward compensation is designed to adjust ATR, and feedback controller is used to statue...
In this paper, a delayed worm propagation model with birth and death rates is discussed. The number of system reinstallations may be increased when the hosts get unstable (infected or quarantined). In view of such situation, dynamic birth and death rates are introduced. Afterwards, the stability of the positive equilibrium is studied. Through the theoretical analysis, it is proved that the model is...
Due to the vulnerability of computer system, Internet worm is still greatly threatenning network security. It is found that the spread of worm regularly change because of the different space distributions of hosts and this phenomenon is defined as diurnal pattern. Based on diurnal pattern, two worm propagation models, namely simple diurnal forced model and complicated diurnal forced one, are constructed...
A nonlinear field model—Faddeev model is discussed. By defining the suitable variables, the vector nonlinear partial differential field equation of Faddeev model is reduced to some simple ones. By utilizing the knowledge of differential geometry to solve the field equation, the analytical solutions of the model are obtained.
Two-dimensional blade element/momentum theory (BEMT) is often used in designing and calculating the performance of the blades of the wind turbine. However, in stalled conditions, the wind turbine rotor power output is under-predicted. This phenomenon, in which there are differences between the measured performances and predications based on 2D aerofoil characteristics in stalled condition, is so-called...
In this paper, a worm propagation model with pulse quarantine strategy is proposed to control the spread of the worm. This model which combines both the pulse quarantine and the constant quarantine strategy not only describes the propagation of the worm well and but also makes the infections eradicated effectively. Here, we show that there exits a stable infection-free periodic solution of the system...
A chaotic worm propagation model is proposed to analyze early worm propagation process in this paper. Worm propagation is very complex, whose major transitions are between regular cycles and irregular, possibly chaotic epidemics. This paper deals with a discrete mathematical model of early worm propagation systems: Chaotic Susceptible-Infected (CSI) model. In the CSI model, three threshold values...
Reynolds number has a direct impact on the performance of a wind turbine aerofoil. In this paper, the airfoil NREL S809 was chosen for the research, using numerical simulation and experiment for the performance of the two-dimensional aerodynamic airfoil flow. While Reynolds number varies from 1.5times104 to 2times105, both the drag coefficient and the lift coefficient have great changes. However,...
Due to the features of interaction between malicious codes, the cooperation becomes more and more common. In this paper, cooperation between worm and virus is discussed in detail, and a cooperation model named CM model is proposed to describe the dynamical process of propagation. Results of simulation and mathematic analysis show that the propagation performance is significantly improved with the...
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