无线电掩星滑动频谱方法和后传播方法的分析比较

本文详细介绍了滑动频谱方法,并通过模拟仿真和实测资料处理与后传播方法进行比较. 通过对模拟仿真信号反演发现:后传播方法和滑动频谱方法均能削弱大气多路径的影响,后传播方法在一定程度上优于滑动频谱方法;在模拟信号的相位中加入高斯噪声对后传播方法影响不大,但对滑动频谱方法影响较大,尤其在边界层以下. 分别用后传播方法和滑动频谱方法对2007年第71天至73天共约4500个COSMIC掩星数据进行处理. 将折射率反演结果与ECMWF分析场资料进行统计比较,结果显示:滑动频谱方法反演的掩星廓线深度大于后传播方法;后 关键词： GPS/LEO掩星 多相位屏模型 后传播方法 滑动频谱方法     

脉冲软X光辐射三种材料的喷射冲量实验研究

 在强光一号脉冲加速器上进行了国内首次的实验室软X光辐射三种材料的喷射冲量研究。结果表明，在能量为(0.2～0.33)keV、平均脉宽为39ns左右的X光辐射下，对灰漆、白漆和硬铝，在能注量分别为(92～152)J/cm²、(115～136)J/cm²和(163～192)J/cm²时，它们的冲量耦合系数分别为(0.61～0.80)Pa·s/(J·cm^-2)、(0.58～0.97)Pa·s/(J·cm^-2)和(0.61～0.84)Pa·s/(J·cm^-2)。     

新媒体时代广电编导专业应用型人才培养模式的创新

人类今天所处的时代,是一个传媒业大变革、大发展的时代。新媒体、新技术的不断涌现,互联网的普及和应用,移动媒体的快速发展,使得我们所处的信息环境和面对的媒体格局发生了空前变化。在此背景下,广播电视编导专业的人才培养也应发生相应的改变,应通过构建实践教学体系、实现产学研的有机结合、增加新媒体方面的课程、运用多种教学方法和考核手段等方面培养适应新媒体时代的应用型传媒人才。     

手持台广播功能在地铁广播中的应用

随着地铁事业的急速发展,现有的地铁广播系统已经不能满足实际需要。无线手持机广播功能的实现,提供了一种解决问题的有效途径。本文介绍了无线手持台广播系统的构成、主要设备及接口形式,论述了无线手持台广播功能的实现流程。这一技术在我国地铁领域有较大的推广价值。     

Cooperation within the Small Cell: The indoor,correlated shadowing case

The deployment of Small Cells in fourth generation (4G) communication systems is aimed at providing significant capacity improvements and higher availabilities. However, the design of Small Cell systems in indoor environments is especially challenging due to high shadowing attenuation induced by clutter and human blockage. This paper studies node cooperation and multiple relaying and proposes novel analytical formulas for the outage probability of cooperative Small Cells suffering from shadowing. The channel fading gains are modeled as correlated lognormal random variables, in order to reflect the properties of indoor propagation environments. Various cooperative strategies are considered, taking into account the use of one or two relays and different receiver combining techniques. In addition, the relative performance of each cooperative configuration and the benefit of cooperation over non-cooperation are investigated. Finally, interesting and useful insights are produced regarding the impact of the correlated lognormal environment parameters on the configuration of cooperative Small Cells.     

无线数传电台实现远程供水控制设计

本文分析了数传电台同GSM、CDMA等无线传输方式的优缺点,最终选型选型为无线数传电台同PLC共同配合工作实现的无线水塔供水控制方式。解决了水源地、水塔、值班室三者距离较远、I/O点分散的问题,经使用安全可靠取得了良好的效果。     

Dempster-Shafer （D-S） algorithm with credit scale in spectrum sensing

In cognitive radio, the detection probability of primary user affects the signal receiving performance for both primary and secondary users significantly. In this paper, a new Dempster-Shafer (D-S) algorithm with credit scale for decision fusion in spectrum sensing is proposed for the purpose to improve the performance of detection in cognitive radio. The validity of this method is established by simulation in the environment of multiple cognitive users who know their signal to noise ratios (SNR) and a central node. The channels between the cognitive users and the central node are considered to be additive white Gaussian noise (AWGN). Compared with traditional data fusion rules, the proposed D-S algorithm with credit scale provides a better detection performance.     

Absence of Cherenkov properties of coherent radio emission from atmospheric showers at frequencies below 100 MHz

In many modern papers devoted to the calculation of radio emissions from extensive atmospheric showers (EASs) in the 10–100 MHz range, the radiation from EASs of charged particles moving with a velocity higher than the speed of light in air is identified as Vavilov—Cherenkov radiation (VCR). In this paper it is shown that radio emissions from EASs at frequencies less than 100 MHz do not possess the properties of VCR recorded from EASs in the optical range. Original Russian Text ? N.N. Kalmykov, A.A. Konstantinov, 2009, published in Vestnik Moskovskogo Universiteta. Fizika, 2009, No. 3, pp. 99–102.     

A relay selection scheme based on geometric optimum in cooperative cognitive systems over mixed channels

This paper proposes a relay selection scheme based on geometric optimum principle to maximize the cognitive link＇ s connectivity with limited interference to primary user in cooperative cognitive systems. A dual-hop cognitive relay system is considered, in which the channel impulse response follows independent non-identical distribution （i. n. d. ） each hop, such as Rician, Rayleigh and Nakagami-m distribution. Then, closed-form expressions in terms of outage probability and average bit error rate （ABER） are obtained using amplify-and-forward （AF） relaying protocol over such mixed fading channels. Furthermore, the best range of the relay is derived. Extensive simulation re- suits are conducted to verify the theoretical analysis, which is useful to the network optimal design.     

一种改进的射频识别数据自适应清洗算法

根据射频识别(RFID)数据特性,对RFID数据自适应清洗算法SMURF进行改进,使其能够更加高效率地处理RFID漏读数据.实验证明,改进后算法较原算法性能更加优越,准确率和稳定性有了进一步提高.