An improved high order nite di erence method for low Mach number computational aeroacoustics (CAA) is described. The improvements involve the conditioning of the Euler equations to minimize numerical cancellation errors, and the use of a stable non-dissipative sixth-order central spatial interior scheme and a thirdorder boundary scheme. Spurious high frequency oscillations are damped by a third...

In this paper, a new two-sampling scheme is proposed to construct appropriate confidence intervals for the lower population quantiles. The confidence intervals are determined in the parametric and nonparametric set up and the optimality problem is discussed in each case. Finally, the proposed procedure is illustrated via a real data set. 

lightning is a characteristic of severe weather and often associated with hail and heavy rainfall. it is a natural hazard with potential threat to human life and considerable damages to aviation structures. therefore, lightning prediction is critical and the real-time lightning detection systems are able to determine the location of cloud-to-ground (cg) lightning strikes accurately.generally ma...

Xinjun Du, Ying Wang, Jianhua Ge and Yumin Wang Key Laboratory of Computer Networks and Information Security Xidian University Abstract: Chameleon signatures are non-interactive signatures based on a hash-and-sign paradigm, and similar in efficiency to regular signatures. The distinguishing characteristic of chameleon signatures is that there are non-transferable, with only the designated recip...

This paper presents an improvement of the Visual Pattern image coding (VPIC) scheme presented by Chen and Bovik in [2] and [3]. The patterns in this improved scheme are defined by morphological operations and classified by absolute error minimization. The improved scheme identifies more uniform blocks and reduces the noise effect. Therefore, it improves the compression ratio and image quality i...

a fuzzy observer based scheme for synchronizing two hyperchaoticoscillators via a scalar transmitted signal for cryptographic application isproposed. the takagi-sugeno fuzzy model exactly represents chaotic systems.based on the general fuzzy model, the fuzzy observer of a chaotic system isdesigned on the basis of the n-shift multiple state based key encryption algorithm.the scalar transmitted s...

A necessary and suucient condition for an immersed surface in 3-space to be lifted to an embedding in 4-space is given in terms of colorings of the preimage of the double point set. Giller's example and two new examples of non-liftable generic surfaces in 3-space are presented. One of these examples has branch points. The other is based on a construction similar to the construction of Giller's ...