Random Wandering Around Homoclinic-like Manifolds in Symplectic Map Chain

We present a method to construct a symplecticity preserving renormalization group map of a chain of weakly nonlinear symplectic maps and obtain a general reduced symplectic map describing its long-time behaviour. It is found that the modulational instability in the reduced map triggers random wandering of orbits around some homoclinic-like manifolds, which is understood as the Bernoulli shifts.Comment: submitted to Prog. Theor. Phy

Using abnormal TTL values to detect malicious IP packets

In general, an IP packet passes through less than 30 routers before it reaches a destination host. According to our observations, some IP packets have an abnormal time-to-live (TTL) value that is decreased by more than 30 increments from the initial TTL. These packets are likely to be generated by special software. We assume that IP packets with strange TTL values are malicious. This study investigates this conjecture through several experiments, and the results show that malicious packets can be discriminated from legitimate ones by observing only TTL values

Derivation of Non-isotropic Phase Equations from a General Reaction-Diffusion Equation

A non-isotropic version of phase equations such as the Burgers equation, the K-dV-Burgers equation, the Kuramoto-Sivashinsky equation and the Benney equation in the three-dimensional space is systematically derived from a general reaction-diffusion system by means of the renormalization group method.Comment: 21pages,no figure

Rotational spectroscopy of AlO: Low N transitions of astronomical interest in the X^2 Sigma^+ state

The detection of rotational transitions of the AlO radical at millimeter wavelengths from an astronomical source has recently been reported. In view of this, rotational transitions in the ground X^2 Sigma^+ state of AlO have been reinvestigated. Comparisons between Fourier transform and microwave data indicate a discrepancy regarding the derived value of gamma_D in the v = 0 level of the ground state. This discrepancy is discussed in the light of comparisons between experimental data and synthesized rotational spectra in the v = 0, 1 and 2 levels of X^2 Sigma^+. A list of calculated rotational lines in v = 0, 1 and 2 of the ground state up to N' = 11 is presented which should aid astronomers in analysis and interpretation of observed AlO data and also facilitate future searches for this radical.Comment: To appear in Astronomy and Astrophysic