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频谱管理的目的是控制干扰和提高频谱利用率,从而实现频谱使用价值的最大化。随着新的无线电技术和业务对频谱需求的增加,当前的静态频谱管理方法导致频谱拥塞的问题。动态频谱接入能很好地提高频谱利用率,但可能会给通信系统造成一定的干扰。针对这个问题,本文提出了在动态频谱接入的频谱管理中采用基于服务质量的干扰门限设置和基于频谱占用度统计的频谱感知接入,从而在降低干扰的同时提高频谱利用率。 相似文献
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在现代战争中,战场频谱管理是夺取制电磁频谱权的重要保障。针对当前战场频谱管理的热点问题,通过介绍动态频谱管理因素、基于服务的动态频谱管理体系架构、动态频谱管理层次分析和动态频谱管理系统模型,对动态频谱管理技术进行研究,并详细分析了系统级动态频谱管理和网系级动态频谱管理。 相似文献
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认知无线网络中基于用户需求和频谱聚合的动态频谱分配 总被引:1,自引:0,他引:1
认知无线电技术可以感知周围无线环境择机利用频谱空洞,从而达到提高频谱效率的目的.在认知无线电网络中,现有的频谱分配算法大部分是基于连续频谱分配并且没有考虑用户的需求.但是连续频谱分配会生成许多小于用户需求的频谱片段,这些频谱片段不能被充分利用,从而造成频谱浪费.本文基于图论提出了一种联合考虑用户需求和非连续频谱聚合的频谱分配算法.在该算法中,非连续的频谱片段被聚合以尽可能多地满足用户总需求,充分利用了小的频谱片段,避免了频谱浪费,从而提高频谱效率. 相似文献
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无线电频谱资源是不可再生的重要资源,在频谱管理中应当考虑的三个重要因素中列第一位的就是频谱的有效利用,其他的两个因素则分别是频谱共享和经济因素。频谱占用度是频谱有效利用的体现,频谱占用度的测量结果不仅可以为频谱管理人员提供有关频谱实际使用情况的信息,方便频谱管理人员指配频率,同时还可以为频率主管部门提供频谱使用趋势的信息。频谱占用度测量是无线电管理日常监测工作中的一项重要内容。 相似文献
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The article describes a model representation of radar probing data in form of a mixture of background and target samples, which is the sum of two random variables with very different parameters. For model development we research the behavior of the central moments of the distribution mix without assuming the distribution law form. An example it is described the detection of the signal at the output of compression system of chirp ionosonde. 相似文献
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《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1968,56(6):1024-1032
Assuming that visual responses are due to the action of particles on the membrane of the visual cells, the stochastic variability of the response should be a function of the number of particles producing it. Quantitative predictions can be made with the aid of a model proposed in previous articles. It is found that responses produced in visual cells of Limulus by absorption of a single photon have the stochastic properties which would be expected if the response to one photon were brought about by 25 particles. It is concluded from this that the processes leading to visual responses produce multiplication of particles. The effects of temperature and of metabolic poisons suggest that these processes are of chemical nature. 相似文献
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“计算机组成原理”设计性实践教学模式研究 总被引:1,自引:0,他引:1
本文阐述了"计算机组成原理"设计性实验教学的重要性,对设计性实验教学的目的和基本特征进行了归纳,对"计算机组成原理"设计性实验教学的现状进行了调查,对存在的问题进行了较深入的分析;在此基础上.对组成原理设计性实验的教学模式进行了研究,对设计性实验的体系进行了初步设计,并对"计算机组成原理"设计性实验的实施方法进行了探讨. 相似文献
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近红外光谱技术在水果品质无损检测中应用的研究与现状 总被引:6,自引:0,他引:6
简单概述了我国水果产业的发展现状,着重阐述了国内外利用近红外光谱技术进行水果品质无损检测的最新研究进展,分析了当今研究中存在的问题,并对利用近红外光谱技术进行水果检测的前景进行了展望,提出了一些建议。 相似文献
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A. M. Emel’yanov 《Semiconductors》2010,44(9):1134-1139
A method for analyzing the luminescence spectra of semiconductors is suggested. The method is based on differentiation of
the spectra. The potentialities of the method are demonstrated for luminescence in the region of the fundamental absorption
edge of Si and SiGe alloy single crystals. The method is superior in accuracy to previously known luminescence methods of
determining the band gap of indirect-gap semiconductors and practically insensitive to different conditions of outputting
radiation from the sample. 相似文献
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《IEEE transactions on information theory / Professional Technical Group on Information Theory》1970,16(3):299-302
It is shown that the asymptotic behavior of the tail of the sum distribution of a finite number of individually log-normal distributed variates displays the log-normal character of those variates with maximum logarithmic variance. A quantitative definition of the sum-distribution "tail" is established in terms of upper bounds on the relative error or deviation from the asymptotic log-normal property. 相似文献
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On the basis of scaling invariance of the process of random walk, a discrete three-dimensional algorithm is developed and
implemented for computer simulation of the multistage processes of formation of porous clusters in a crystal matrix. A software
package is worked out that provides the simulation of dynamic processes of clustering deep in the crystals with allowance
for surface processes, applied external fields, and chemical reactions accompanying the processes of clustering. The morphological
pattern of pores formed by the simulation is correlated with the behavior of the current-voltage characteristic of anodizing. 相似文献
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A. D. Shatrov 《Journal of Communications Technology and Electronics》2007,52(8):842-849
It is shown that the problem of excitation of a magnetodielectric layer with parameters ? and μ equal to minus unity by a point source is not always solvable. Conditions under which the problem has a solution are established. It is found that, in the vicinity of the singular point ? = μ = ?1, determination of the field is an illposed problem: Small variations in these parameters result in large changes of the field. 相似文献