The permanence of a higher order discrete time system

The permanence of a nonlinear higher order discrete time system from macroeconomics is studied, and a sufficient condition is proposed for the permanence of the system described by 11(,...,)nnnnkxrxfxx---=+ where :kfRR, the initial values 01,,kxx-are real numbers and [0,1)r is constant after exploring the relationship between this equation and 1(,...,)nnnkxfxx--= for certain classes of function f. As an application a short proof is given to a known result in a simpler way than ever reported.

A scheme of optical interconnection for super high speed parallel computer

An optical cross connection network which adopts coarse wavelength division multiplexing (CWDM) and data packet is introduced. It can be used to realize communication between multi-CPU and multi-MEM in parallel computing system. It provides an effective way to upgrade the capability of parallel computer by combining optical wavelength division multiplexing (WDM) and data packet switching technology. CWDM used in network construction, optical cross connection (OXC) based on optical switch arrays, and data packet format used in network construction were analyzed. We have also done the optimizing analysis of the number of optical switches needed in different scales of network in this paper. The architecture of the optical interconnection for 8 wavelength channels and 128 bits parallel transmission has been researched. Finally, a parallel transmission system with 4 nodes, 8 channels per node, has been designed.

Branching fractions of B(c) decays involving J/ψ and X(3872)

We study two-body B（c）→Mc（π,K） and semileptonic Bc→Mcl^-v^-1 decays with Mc=（J/φ,Xc^0）,where Xc^0=X^0（3872） is regarded as the tetraquark state ccuu（dd）.With the decay constant fxc^0=（234±52） MeV determined from the data,we predict that B（B^-→Xc^0π^-） =（11.5±5.7）×10^-6,B（B^0→Xc^0K^-0）=（2.1±1.0）×10^-4,and B（Bs^0→Xc^0K^0）=（11.4±5.6）×10^-6.With the form factors in QCD models,we calculate that B（Bc^-→Xc^0π^-,Xc^0K^-）=（6.0±2.6）×10^-5 and（4.7±2.0）×10^-6,and B（Bc^-→J/φμ^-vμ^-vμ,Xc^0μ^-v^-μ）=（2.3±0.6）×10^-2 and（1.35±0.18）×10^-3,respectively,and extract the ratio of the fragmentation fractions to be fc/fu=（6.4±1.9）×10^-3.

A new burst assembly technique for supporting QoS in optical burst switching networks

This letter proposes a new burst assembly technique for supporting QoS in optical burst switching (OBS) networks. It consists of the adaptive-threshold burst assembly mechanism and QoS-based random offset-time scheme. The assembly mechanism, which is fit well to multi-class burst assembly, not only matches with IP QoS mechanism based on packet classification, and also utilizes fairly and efficiently assembly capacity. Based on token-bucket model and burst segment selective discard (BSSD), the offset-time scheme can smooth the traffic to support OBS QoS. The simulation results show that the technique can improve the performance in terms of packet loss probability (PLP).

p-RWBO:a novel low-collision and QoS-supported MAC for wireless ad hoc networks

QoS supported MAC mechanism is a key issue for supporting QoS in wireless ad hoc networks. A new backoff algorithm, named RWBO＋BEB, was proposed previ- ously to decrease the packet collision probability significantly. In this paper, it is explored how to make RWBO＋BEB support service differentiation in wireless ad hoc networks, and a novel proportional service differentiation algorithm, named p-RWBO, is proposed to allocate the wireless bandwidth according to the band- width ratio of each station. In p-RWBO, station n＇s walking probability （Pw,n） is selected according to its allocated bandwidth ratio. An analytical model is proposed to analyze how to choose Pw, n according to the bandwidth ratios of station n. The simulation results indicate that p-RWBO can differentiate services in terms of both bandwidth and delay.