BDS/GPS双星座卫星轨道RAIM检测算法优化

接收机自主完好性检测中,传统的故障检测方法通常只对单一故障卫星进行识别。但当接收机能接收多个导航星座信息时,多颗卫星同时发生故障概率增加,传统故障检测的方法计算子集快速增加,影响检测效率。针对上述问题,提出将卫星按轨道分组,构造故障检测子集的方法,降低检测子集数量,简化故障检测策略,并通过对双故障卫星进行边缘检测,验证算法的性能。仿真结果表明,卫星轨道方法能有效的检测与隔离双星故障情况,降低了计算复杂度,在伪距误差不小于70m时,对于双卫星故障的检测效率较高。

一种基于协议分析和免疫原理的网络入侵检测模型

通过对协议分析技术和生物免疫系统的理论分析,本文提出一种新的基于协议分析和免疫原理的网络入侵检测模型。该模型对检测器集合按照协议类型分类,生成相应的检测器子集,并设计一种新的检测器结构,对检测器进一步分类。每个子集中检测器独自进行变异、进化,整个检测器集合以子集为单位进行更新。在实际检测中,待检模式与相应的检测器子集匹配,从而能有效地提高检测速度,改进以往模型在这方面的不足。

OPTIMAL ANTENNA SUBSET SELECTION AND BLIND DETECTION APPROACH APPLIED TO ORTHOGONAL SPACE-TIME BLOCK CODING

An approach combining optimal antenna subset selection with blind detection scheme for Orthogonal Space-Time Block Coding (OSTBC) is proposed in this paper. The optimal antenna sub- set selection is taken into account at transmitter and/or receiver sides, which chooses the optimal an- tennas to increase the diversity order of OSTBC and improve further its performance. In order to en- hance the robustness of the detection used in the conventional OSTBC scheme, a blind detection scheme based on Independent Component Analysis (ICA) is exploited which can directly extract transmitted signals without channel estimation. Performance analysis shows that the proposed ap- proach can achieve the full diversity and the flexibility of system design by using the antenna selec-tion and the ICA based blind detection schemes.

Robust and efficient quantum private comparison of equality with collective detection over collective-noise channels

We present a protocol for quantum private comparison of equality(QPCE) with the help of a semi-honest third party(TP).Instead of employing the entanglement,we use single photons to achieve the comparison in this protocol.By utilizing collective eavesdropping detection strategy,our protocol has the advantage of higher qubit efficiency and lower cost of implementation.In addition to this protocol,we further introduce three robust versions which can be immune to collective dephasing noise,collective-rotation noise and all types of unitary collective noise,respectively.Finally,we show that our protocols can be secure against the attacks from both the outside eavesdroppers and the inside participants by using the theorems on quantum operation discrimination.

Dynamics of dense spin ensemble excited in a barrier layer and detected in a well

Photoluminescence (PL) polarization of a spin ensemble was examined over a wide excitation wavelength range from 520 nm to 700 nm and a temperature range from 3.5 K to 300 K after it transfers from a (AlGa)As barrier layer and eventually quenches irradiatively in a GaAs quantum well (QW).A highest PL circular polarization of 30% can be kept at temperatures up to 120 K,while its room temperature value reaches about 17%.It is found that the main features of the optical spin orientation in bulk Al 0.27 Ga 0.73 As materials can be reproduced in terms of the wavelength dependence of PL polarization degree,as the spin polarized ensemble transfers and relaxes into GaAs QW.The transient of PL polarization degree also indicates that a dense spin ensemble collected from the barrier region is in favor of conserving its polarization in GaAs QW as evidenced by a rising temporal response.

Organic nanoparticles formed by aggregation-induced fluorescent molecules for detection of hydrogen sulfide in living cells

Hydrogen sulfide(H_2S)has been found to be the third most important endogenous gaseous signaling molecule after nitric oxide(NO)and carbonic oxide(CO)and plays crucial roles in living organisms and biological systems.Here we use aggregation-induced emission(AIE)of a small organic molecule(TPE-indo)to detect H_2S in both solution and living cells.TPE-indo can target mitochondria and aggregate to fluoresce,which can serve as a sensor for monitoring H_2S in the mitochondria.We regulate the fluorescence of AIE molecules by tuning the viscosity of the solution to form TPE-indo nanoparticles,constructing a probe for H_2S with good selectivity and high sensitivity.The nucleophilic addition of HS-to the TPE-indo is crucial for the rapid H_2S detection.The imaging and analysis of H_2S in mitochondria of living cells with the probe demonstrate potential biological applications.