Papers by Keyword: Self-Organized Criticality

Abstract: In this paper a blackout AC power flow model considering the probability of line stoppage in the process of power grid growth is given,and the self-organized critical state in the process of power grid growth is studied with the power grid upgrade rate is equal、greater or less than the load growth rate.Simulation results show that power grid upgrading rate must meet the system's load growth, or the probability of failure will be greatly increased with the grid exceed the critical state while the load growth faster than the grid upgrading in the long process of building the power grid. The model and simulation results presented in this paper provide a theoretical basis for the planning and construction of the power grid.

Abstract: By studying the service property of different travel modes, the self-organization theory presented in this paper to research the self-organized criticality, highlighting by the discovery and description of self-organized critical condition of travel mode choice, is of inspiring importance. The state equation and critical property analysis proposed in the paper is validated by practical example in Macao.

Abstract: In emergency, the crowd evacuation from public buildings is the most important issue to save human lives. Panic generation and spread normally can lead to the unstable state -stampede during the crowd motion. The stability of crowd evacuation is a complex problem being researched for decades. This paper introduces self-organized criticality(SOC) theory to build the mapping model from a collective crowd into a sand pile with SOC. Therefore, the complex problem of stability analysis for crowd evacuation is converted into sandpiper stability analysis in a relatively simpler way.

Abstract: Many important nature evolution phenomena can be explained with Self-organized criticality (SOC) theory. SOC theory explains the tendency of large dissipative systems to drive themselves into a scale-invariant critical state without parameter adjustment. These phenomena are of crucial importance because fractal objects displaying SOC are found. This paper analyzes the characteristics of SOC theory, and then introduces basic principles of SOC theory in one-dimension model. Based on the self-organized criticality owned by the high-density pedestrian evacuation and even the trample event, this paper proposes the potential applications of SOC theory to explain the various phenomena in pedestrian evacuation from public buildings in unconventional emergencies.

Abstract: The distribution of power flow is a determinant of power grids self-organized criticality, and the uniformity of power flows distribution can be quantified by power flow entropy. The theory of power flow entropy is applied in this article to the research of influencing factors of power grids self-organized criticality. First the mathematics mechanism of self-organized criticalitys quantifying by power flow entropy is researched. And then the influence of start-up mode (source), running state (network), load distribution (load) on power flow entropy is analyzed respectively. Finally, the Hexi grid located in Gansu province is employed to verify the critical influences of source-network-loads operation mode on power grids self-organized criticality.

Abstract: Temperature dependence of different parameters (the position of the inflexion point and the saturation value on the root main square, RMS, values versus exciting field curves) of the Barkhausen noise is measured in structural steel (S 235 JRG1). It is shown that while the position of the inflexion point remained constant, the RMS value at the inflexion point and saturation value increased with the increasing temperature, T. Most interestingly the field required for saturation decreased with decreasing temperature and had a breakpoint at about 200K. Breakpoints at the same temperature on the critical exponents versus temperature functions (i.e. on the β(T) and α(T) curves, where β and α are the exponents of the probability distributions of peak heights and durations, respectively) were also observed. This temperature can be identified as the ductile-brittle transition temperature.

Abstract: Barkhausen noise properties of amorphous and nanocrystallized FINEMET type soft magnetic materials are investigated. It is obtained that the amorphous-nanocrystalline tranformation has a well observable effect on both the root main square, RMS, values and the critical exponents of the probability distributions of peak heights and durations.