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研究表明,接入网投资已约占当前整个电信网投资的50%,但目前接入网建设却跟不上骨干网建设步伐和用户业务需求的发展,容量和成本的瓶颈问题因业务宽带化而显得尤为突出。接入网建设需要大量的先期投入,各种接入技术不能很快地应用在接入网中,这给电信运营企业带来很大压力。接入网的建设是一项长期工程,正确、全面地理解和比较各种技术的优势以及局限性,选择最适合的技术组合对接入网的建设具有相当重要的意义. 相似文献
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接入网网络的分层组织 总被引:1,自引:0,他引:1
介绍接入网的分层建设概念,即物理上分为主干层,分配层和引入层,并分别介绍了各层在网络组织和建设中应考虑的因素及应注意的问题。随着接入网规划,建设的进一步开展,接入网网络的组织、实施方法已引起人们的普遍重视。 相似文献
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瞿宏专 《电信工程技术与标准化》2001,(1):69-70
接入网概念的提出始于1994年ITU-T关于V5接口标准的制定。在传统通信网中,接入网部分建设的比重约为30%。40%。随着技术和业务的发展,特别是随着Internet的爆炸性增长和其它宽带数据业务的发展,综合业务接入网的建设将成为今后网络建设的重点。据有关专家分析,作为最靠近用户的基础网络的接入网是反映各电信运营商网络竞争力的关键因素,也是反映网络服务质量的关键所在。在现阶段,建设综合业务接入网应充分考虑如下几个问题。1宽带接入网的出发点 宽带接入网的引入是基于数据业务的飞速发展,特别是IP业… 相似文献
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该文针对各运营商,从目前城域接入网的问题入手,着重分析了用户对于接入宽带和业务的需求,并提出华为公司完善的数据城域接入网建设思路和方案-SBI策略,阐述了在当前情况下,城域接入网的建设是一个全面的带宽建设,而不仅仅是宽带接入网的建设。 相似文献
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介绍了接入网中V5接口的基本概念及与交换机对接的测试方法,重点描述了在接入网和交换机的互操作性测试过程中出现的几个问题并加以分析,同时依据现有的国际国内标准提出处理意见,为广东省的接入网建设提供参考。 相似文献
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针对中国移动集团业务发展的需求,分析当前接入网建设中存在的大量“哑设备”问题,根据集团业务特性,提出一套智能接入网演进方案。 相似文献
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本文在简述接入网及其技术的基础上,结合我市接入网的建设计划,就当前接入网建设中需要考虑的若干技术问题提出一些观点和看法. 相似文献
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The One-More-RSA-Inversion Problems and the Security of Chaum's Blind Signature Scheme 总被引:1,自引:0,他引:1
We introduce a new class of computational problems which we call the ``one-more-RSA-inversion' problems. Our main result
is that two problems in this class, which we call the chosen-target and known-target inversion problems, respectively, have
polynomially equivalent computational complexity. We show how this leads to a proof of security for Chaum's RSA-based blind
signature scheme in the random oracle model based on the assumed hardness of either of these problems. We define and prove
analogous results for ``one-more-discrete-logarithm' problems. Since the appearence of the preliminary version of this paper,
the new problems we have introduced have found other uses as well. 相似文献
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It is well known that a large variety of systems and control problems can be formulated as optimization problems. The classical approach pursued in typical contexts is to look for a closed form solution to the specific optimization problem at hand. The last decade has seen a noticeable shift in the meaning of "closed form" solution. The formidable increase of computational power has dramatically changed the feeling of theoreticians as well as of practitioners about what is meant by "tractable" and "untractable" problems. One of the main issues is convexity. While from a mathematical viewpoint there has been a large amount of work in the direction of "convexifying" nonconvex problems and studying structural features of convex problems, considerable advances on techniques for recognizing convexity and algorithms for solving convex problems have been made mainly in the last 15 years [1, 2]. Efforts in this direction are motivated by the recognition that a large number of engineering problems can be formulated as convex problems. 相似文献
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微波组件产品广泛地应用于通信和导航等领域,其可靠性的高低是影响电子装备可靠性的重要因素。通过对55个微波组件产品的失效案例进行统计分析,得出了微波组件失效的原因,其中主要原因是操作问题、工艺问题、调试问题、元器件问题和用户使用问题,分别对这5类问题进行了具体分析和说明。从设计、生产、采购、检验和使用等方面分析了影响微波组件质量的因素,提出了相应的质量控制方法和应注意的问题。为微波组件的质量控制提供了有价值的统计数据和分析结果。 相似文献
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混沌优化算法在组合优化问题中的应用 总被引:3,自引:0,他引:3
组合优化问题一直都受到理论界和工程界的重视,此类问题的求解方法也有很多,却各有缺点和局限性,不能满足实际应用的需要。混沌优化算法在解决数值优化问题上具有一定的普遍性,可以很快找到全局最优解,不过组合优化问题的解不是一个数值,因此在前人研究的基础上,提出求解组合优化问题的混沌优化算法。首先分析混沌优化,并针对组合优化问题中的TSP问题,提出一种混沌优化策略,探讨在TSP问题中应用混沌优化算法的方法。结果表明了该方法的有效性。 相似文献
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This paper presents a search method based on lexicographic order, and an upper bound on the objective function, for solving redundancy allocation problems in coherent systems. Such problems generally belong to the class of nonlinear integer programming problems with separable constraints and nondecreasing functions. For illustration, 3 types of problems are solved using our method. Numerical investigation shows the performance of the method for large problems 相似文献
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This paper presents an overview of results related to the computational complexity of network reliability analysis problems. Network reliability analysis problems deal with the determination of reliability measures for stochastic networks. We show how these problems are related to the more familiar computational network problems of recognizing certain subnetworks, finding optimal subnetworks, and counting certain subnetworks. We use these relationships to show that the k-terminal, the 2-terminal, and the all-terminal network reliability analysis problems are at least as hard as the renowned set of computationally difficult problems, NP-Complete. Finally, we discuss the impact of these results on how one should approach problem solving in this area. 相似文献
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录音文件是有声语料库的基础组成部分,在进行语音数据采录时,由于录音环境、录音技术等方面的原因,录制完成的录音会存在各种问题和不足.结合国内大型语料库建设过程实践,对录音中存在的问题进行了深入分析,针对性地提出了避免各种问题出现的措施和解决出现的相关问题的方法. 相似文献