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《中兴通讯技术(英文版)》2008,(4):69-69
We keep about 16,000 engineers on the ground across three continents to hear and understand your customers’ demands. 相似文献
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Secure communications for vehicular ad hoc networks (VANETs) have become an important research issue these years. Many protocols for secure vehicle-to-vehicle communications and vehicle-to-infrastructure communications have been proposed, yet fewer protocols are concerned with secure group communications for VANETs. Of those existing protocols for group communications, some of them form a group of vehicles based on geographical regions and provide broadcasting to the group members with or without message confidentiality. The others allow secure vehicle-to-vehicle communications within a group with session keys, but they do not preserve user privacy for communicating parties within the group. In this paper, we propose a novel group communication scheme for vehicular networks, in which a group is formed by a set of related vehicles of the same purpose, such as a platoon of recreational vehicles targeted for the same tourist spot. The scheme not only offers efficient and secure group communications but also provides privacy preservation for vehicle-to-vehicle communications within a group. Security analysis is given to demonstrate the robustness of the proposed scheme. 相似文献
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As low-power wide-area network (LPWAN) end devices (EDs) are deployed in massive scale, their economic and environmental costs of operation are becoming too significant to ignore and too difficult to estimate. While LPWAN architectures and protocols are designed to primarily save energy, this study shows that energy saving does not necessarily lead to lower cost or environmental footprint of the network. Accordingly, a theoretical framework is proposed to estimate the operational expenditure (OpEx) and environmental footprint of LPWAN EDs. An extended constrained optimization model is provided for the ED link assignment to gateways (GWs) based on heterogeneous ED configurations and hardware specifications. Based on the models, a simulation framework is developed which demonstrates that OpEx, energy consumption, and environmental footprint can be in conflict with each other as constrained optimization objectives. We demonstrate different ways to achieve compromises in each dimension for overall improved network performance. 相似文献
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The impact of information and communications technology (ICT) in tourism (e-tourism) has altered the ways tourism services are accessed and consumed. Ubiquitous and highly innovative ICTs provide different channels for consumers to use tourism services; thus, studies on e-tourism are numerous and fragmented. Different factors account for how consumers embrace these channels. The purpose of this study is to review studies on consumers’ acceptance or adoption of e-tourism in order to group the studies, synthesize the theories, models and frameworks used and identify the antecedents influencing consumers’ e-tourism acceptance and usage. A total of 71 studies from 2005 to 2016 (inclusive) from both tourism-based and non-tourism-based journals were selected, synthesized, and included. Based on their contexts, similarity and relevance, the 71 studies were segregated into three distinct groups. This study found that research among the groups is uneven. Implications and research directions are suggested. 相似文献
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《数字通信世界》2006,(11):95-95
President Zhao Jibin of China Titong goes to Jiangsu to do some surveys and after listening to the working report of Jiangsu Tietong, he inspects the network development in Nanjing, Suzhou, Changzhou and other cities. Zhao JiBin emphasizes China Tietong should be on the way of "enlarge private network coverage and make great progress in network regionalization", make every effort to lay a solid management foundation and improve management level so as to ensure the accurate orientation and implement of the whole development strategy. All members of China Tietong must hold a clear understanding about future development direction. 相似文献
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Manzoor A. Khan Ahmet C. Toker Fikret Sivrikaya Sahin Albayrak 《Telecommunication Systems》2012,51(1):29-41
The increasing number of radio access technologies and the availability of multi-radio devices boost the need for novel resource allocation schemes in cellular networks. This paper uses a cooperative game theoretic approach for resource allocation at the network level, while utilizing simultaneous use of available radio interfaces at the device level. We model resource allocation management using the well known bankruptcy model and apply Kalai-Smorodinsky bargaining solution method to find a distribution rule, based on which we propose resource allocation and call admission control schemes. Performance analysis of our allocation and control schemes demonstrates significant improvements over previous approaches in terms of utilization of the available bandwidth and the number of call drops. We also study the performance of proposed approach for different operator policies. 相似文献
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HAN Gui-hua ZHANG Wei-gang 《光电子快报》2007,3(3):195-198
A novel method of correlation function for analyzing cross-sensitivity between strain and temperature is reported for the first time in this paper. Using the new method,the correlative characteristics between strain and temperature of fiber Bragg grating sensors are studied both theoretically and experimentally The experimental results accord with the theoretical calculations. 相似文献
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Large-scale IP network behavior anomaly detection and?identification using substructure-based approach and?multivariate time series mining 总被引:2,自引:0,他引:2
In this paper, a substructure-based network behavior anomaly detection approach, called WFS (Weighted Frequent Subgraphs),
is proposed to detect the anomalies of a large-scale IP networks. With application of WFS, an entire graph is examined, unusual
substructures of which are reported. Due to additional information given by the graph, the anomalies are able to be detected
more accurately. With multivariate time series motif association rules mining (MTSMARM), the patterns of abnormal traffic
behavior are able to be obtained. In order to verify the above proposals, experiments are conducted and, together with application
of backbone networks (Internet2) Netflow data, show some positive results. 相似文献
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基于改进型头部丢弃的光突发竞争解决方案 总被引:1,自引:0,他引:1
为了避免"部分丢弃"策略两个固有缺陷(即"虚假竞争"和"过量丢弃")的影响,并最大限度地为上层应用提供有区分的承载服务,在加权型突发装配机制、QoS化偏移时间设置的基础上,提出了一种改进型头部丢弃方案.它能按照突发优先级的高低和截断突发相对长度的大小有选择性地丢弃突发头部或整个突发.与其他策略相比,该方案在合适的头部丢弃门限下,其优势较突出:一方面总分组丢失概率有所改善;另一方面具有一定的QoS保障能力,能为不同类别的分组提供有区分的传输服务. 相似文献
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Optimized TQ-MAP: An Adaptive Mapping Mechanism to Guarantee the Coherence of QoS Support from IP to OBS 总被引:1,自引:0,他引:1
Yang Xiaolong Mao Youju Dang Mingrui Zhang Min Li Lemin 《Photonic Network Communications》2003,6(3):279-287
Because of its scalability, the idea of coarse packet classification can be utilized to OBS networks. However, due to the limited number of priorities supported by OBS networks, we usually adopt a many-to-one composite class burst (CCB) assembly technique, e.g., N:1-CCB. In this kind of technique, there are two aspects related to scalable QoS support, i.e., mapping relationship and assembly resource allocation. This paper simultaneously takes the two aspects into consideration, and proposes a novel assembly mapping mechanism, called Optimized TQ-MAP, in which the most important feature is adaptivity. Based on nonlinear programming and differential calculus, it allocates the burst assembling capacity between classes fairly, efficiently and differentially, and matches IP QoS requirement with OBS QoS capacity as possible as it can. The simulation results show that Optimized TQ-MAP is more adaptive, and can efficiently guarantee the coherence of QoS support from IP to OBS. 相似文献
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光突发交换(OBS)网络的城域网应用需要解决与接入网的互连问题。针对基于集成节点的PON与OBS网络互连方案,研究了集成节点的功能与组成结构,分析了模块之间的信息交互,给出了集成节点结构的一种设计方案,并简单讨论了基于这一方案的汇聚机制和动态带宽分配算法。 相似文献
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光突发交换网络中支持业务区分的多路由机制研究 总被引:1,自引:1,他引:0
针对光突发交换(OBS)网络的多路由机制多是考虑一种业务而对多业务区分的多路由机制研究偏少这种现状,提出了一种支持业务区分的多路由(MRSD)机制。在发送各个服务等级的业务之前,首先在没有共享风险链路的多条路由上发送请求包获得各条路由上的多种优先级业务的负载情况,然后根据爱尔兰固定点近似分析法计算各种优先级业务在不同路由上的丢包率,并为每种优先级业务选择一条使本业务丢包率最小的路由;在一个核心节点内,则采用基于额外偏置时间的业务区分方法实现不同优先级业务的区分,将各种业务根据链路状态信息分配到没有共享风险链路的多条路由上去传输,从而在减少突发丢失率(BLP)的同时实现了多种优先级业务在路由上的区分。仿真结果表明,这种多路由机制能够有效降低网络的BLP,实现区分服务。 相似文献
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A burst loss probability model with impatient customer feature for optical burst switching networks 下载免费PDF全文
Hoang‐Linh To Suk‐Hwan Lee Won‐Joo Hwang 《International Journal of Communication Systems》2015,28(11):1729-1740
We consider optical delay line buffer as a solution to reduce the number of lost burst in optical burst switching, one of the promising candidates for future networks. Such network takes burst loss as an important performance criteria in the design step. Network performance, however, cannot be captured efficiently using traditional queueing models, because they often ignore the impatience of messages traveling through optical switches which is one of the popular issues in communication networks. In this paper, we develop an analytic model for this system using queueing theory and considering special impatience features. Simulation results show that (i) the developed model with impatience features can decrease burst loss probability ( ? 10%) compared with other approaches, and (ii) applying that model, we demonstrate that shared buffer architecture in optical burst switching network with optical buffer often achieves lower burst loss probability than dedicated buffer way in several different scenarios. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献