检索结果-内蒙古大学图书馆

IEEE International Symposium on Personal, Indoor and Mobile Radio communications

作者： Serkan Ayaz Felix Hoffmann Reinhard German Falko Dressler German Aerospace Center (DLR) Institute of Communications and Navigation Computer Networks and Communication Systems Dept. of Computer Science University of Erlangen Institute of Computer Science University of Innsbruck

ISBN: (纸本)9781457713460

The aviation community is currently working on the standardization of data communication systems for the future air traffic management. In this context, the International Civil Aviation Organization (ICAO) has initiated a work on standardization of an IPv6-based aeronautical telecommunications network and on future radio access technologies, respectively. In this paper, we integrate L-Band Digital Aeronautical communications System Option 1 (L-DACS 1), which is one candidate for future radio access technologies, with realistic IPv6-based network layer functionality and analyze Deficit Round Robin (DRR) with fragmentation algorithm for the forward and return link in L-DACS 1. Our analysis mainly covers two application domains: file transfer and real-time services. We show that DRR with fragmentation scheduler provides good performance results in terms of throughput, delay, and bandwidth fairness.

关键词： Air traffic management International Civil Aviation Organisation Round robin Telecommunication networks DATA TRANSMISSION systems Standardization Access to technology Analysis

来源：评论

学校读者我要写书评

暂无评论

Multipath routing slice experiments in federated testbeds

引用

Lecture Notes in computer science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) 2011年 6656卷 247-258页

作者： Zseby, Tanja Zinner, Thomas Tutschku, Kurt Shavitt, Yuval Tran-Gia, Phuoc Schwartz, Christian Rafetseder, Albert Henke, Christian Schmoll, Carsten FOKUS - Fraunhofer Institute for Open Communication Systems Berlin Germany Institute of Computer Science University of Wuerzburg Wuerzburg Germany University of Vienna Austria School of Electrical Engineering Tel Aviv University Tel Aviv Israel Department of Next Generation Networks Technical University Berlin Berlin Germany

ISBN: (纸本)9783642208973

The Internet today consist of many heterogeneous infrastructures, owned and maintained by separate and potentially competing administrative authorities. On top of this a wide variety of applications has different requirements with regard to quality, reliability and security from the underlying networks. The number of stakeholders who participate in provisioning of network and services is growing. More demanding applications (like eGovernment, eHealth, critical and emergency infrastructures) are on the rise. Therefore we assume that these two basic characteristics, a) multiple authorities and b) applications with very diverse demands, are likely to stay or even increase in the Internet of the future. In such an environment federation and virtualization of resources are key features that should be supported in a future Internet. The ability to form slices across domains that meet application specific requirements enables many of the desired features in future networks. In this paper, we present a Multipath Routing Slice experiment that we performed over multiple federated testbeds. We combined capabilities from different experimental facilities, since one single testbed did not offer all the required capabilities. This paper summarizes the conducted experiment, our experience with the usability of federated testbeds and our experience with the use of advanced measurement technologies within experimental facilities. We believe that this experiment provides a good example use case for the future Internet itself because we assume that the Internet will consist of multiple different infrastructures that have to be combined in application specific overlays or routing slices, very much like the experimental facilities we used in this experiment. We also assume that the growing demands will push towards a much better measurement instrumentation of the future Internet. The tools used in our experiment can provide a starting point for this. © 2011 The Author(s).

关键词： Testbeds

来源：评论

学校读者我要写书评

暂无评论

Validating UML simulation models with model-level unit tests 10

Validating UML simulation models with model-level unit tests

引用

3rd International ICST Conference on Simulation Tools and Techniques, SIMUTools 2010

作者： Dietrich, Isabel Dressler, Falko Dulz, Winfried German, Reinhard Computer Networks and Communication Systems Department of Computer Science University of Erlangen Germany

ISBN: (纸本)9789639799875

We describe model-level unit tests for model-driven simulation based on UML models. We refer to the well-known unit testing method and apply this concept on a higher abstraction level, that is on UML simulation models. The concept of model-based simulation has become more and more popular throughout the last years. This trend is fostered by the availability of tools that automatically transform UML models into executable simulation code. Typically, both functionality and behavior are modeled in UML, whereas debugging and validation are mainly an issue of investigating the executable code. We contribute to the field of model-driven simulation by defining a novel testing method. Our method allows to use UML to specify model-level unit tests in order to validate simulation models defined with UML. In addition, we describe the translation, execution and evaluation of these tests within the framework Syntony. In this paper, we show the principles of this method and discuss its use in the scope of our simulation framework Syntony as well as its general applicability. Our implementation allows to compile and to execute the test code in combination with the simulation code. In spite of the high abstraction level, the full functionality of unit testing is provided and the modeler can rely on automated test case generation and execution. After execution of the tests, the achieved test coverage is computed as a measure for the test quality. © Copyright 2010 ICST.

关键词： Abstracting

来源：评论

学校读者我要写书评

暂无评论

有限反馈下大规模MIMO系统性能仿真

有限反馈下大规模MIMO系统性能仿真

引用

2012年全国通信理论和信号处理学术年会

作者： XU Guo-zhen 徐国珍 JIANG Wei 蒋伟 LIU An 刘安 XIANG Hai-ge 项海格 LUO Wu 罗武 State Key Laboratory of Advanced Optical Communication Systems and Networks Peking University Beijing 100871 P. R. China 北京大学区域光纤通信网与新型光通信系统国家重点实验室北京 100871 Department of Electrical and Computer Engineering Hong Kong University of Science and Technology HongKong 999077 P. R. China 香港科技大学电子与计算机工程学院香港 999077

大规模多输入多输出(multiple input multiple output,MIMO)系统由于天线数目的急剧增加,其模型与传统多入多出系统有诸多不同,反馈信息对系统性能有较大影响。针对迫零波束成形、有限反馈等条件下,对大规模MIMO系统进行仿真,研究其性能... 详细信息

大规模多输入多输出(multiple input multiple output,MIMO)系统由于天线数目的急剧增加,其模型与传统多入多出系统有诸多不同,反馈信息对系统性能有较大影响。针对迫零波束成形、有限反馈等条件下,对大规模MIMO系统进行仿真,研究其性能,对其实际应用有一定的指导意义。仿真分析表明,有限反馈下的大规模MIMO系统在反馈比特数目较少时与传统MIMO系统性能相仿,当反馈比特达到一定数目后,系统容量性能将显著提升。

关键词：移动电话多输入多输出系统反馈信息仿真分析

来源：评论

学校读者我要写书评

暂无评论

Incident Light Influence on the Transmission of Coupled Ring Resonators

引用

Tsinghua science and Technology 2010年第2期15卷 198-201页

作者：孙月徐连宇彭超李正斌 State Key Laboratory on Advanced Optical Communication Systems & Networks School of Electronic Engineering and Computer Science Peking University

The transmission matrix method is used to analyze the influence of incident light on coupled resonators. Two different types of incident light on the same coupled resonator geometry are shown to lead to different system transmission features. The EIT-like phenomenon occurs in the type I case with the transmission being symmetric around the zero-single-pass-phase-shift frequency. In the type Ⅱcase the resonant frequency has a blue shift corresponding to the increasing coupling strength between the two ring resonators. Also, the critical-coupling-like condition exists in the type Ⅱconfiguration to maintain the zero-single pass-phase-shift frequency. The incident light, as well as the geometry, partially determine the mode interference in the coupled ring resonator system.

关键词： coupled ring resonator mode excitation resonance frequency shift

来源：评论

学校读者我要写书评

暂无评论

Three-Step Carrier Frequency Offset Estimation Algorithm for Burst-Mode communications

引用

电子学报(英文版) 2010年第1期19卷 165-169页

作者： LUO Wu LIU An LIANG Qinglin State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronic Engineering and Computer Science Peking University Beijing 100871 China

A data-aided frequency offset estimation algorithm suited for burst-mode communications is described and analyzed. The proposed algorithm is based on a Pilot symbol assisted modulation (PSAM) frame structure, which consists of regularly spaced pilot symbols and a group of consecutive pilot symbols embedded in. Firstly, an initial estimate based on consecutive pilot symbols is generated for reducing the phase ambiguity. Secondly, based on both spaced and consecutive pilot symbols, fine preliminary estimates are generated to improve estimation accuracy. Lastly, the final estimate is obtained by combining the fine preliminary estimates with the initial. This three-step algorithm is shown to provide high estimation accuracy close to those of FFT-based algorithm at low Signal-to-noise ratio (SNR). In addition, it is suitable for high carrier frequency offset cases.

关键词：频偏估计算法突发模式载波频偏通讯导频符号辅助载波频率偏移 FFT算法 PSAM

来源：评论

学校读者我要写书评

暂无评论

Scheduling complex automotive embedded real-time systems

Scheduling complex automotive embedded real-time systems

引用

2010 IEEE International Conference on Vehicular Electronics and Safety, ICVES 2010

作者： Lauer, Christoph Hielscher, Kai-Steffen German, Reinhard Pollmer, Jens Department of Computer Science 7 Computer Networks and Communication Systems University of Erlangen-Nuremberg Germany Department of Safety Electronics Audi AG Ingolstadt Germany

ISBN: (纸本)9781424471249

The formal verification of task schedulability is getting more important in the automotive domain as more and more applications are integrated into domain specific controllers. Especially for safety critical applications an indepth knowledge about the worst-case response time of tasks is of utmost importance. Such systems often consist of subsystems that comprise of a collection of tasks, called transactions, which are triggered by external events. We adapt a well known response time analysis to analyze asynchronous task sets where subsets may be triggered from different clock references. Therefore we refine the original computational model from the literature to capture the information about transaction clock references. To determine the schedulability of the system we first analyze all task subsets which are triggered by the same clock reference. Then we combine the results to derive the response times for the complete task set. The approach incorporates no overestimation of the response times and therefore represets a necessary and sufficient schedulability test for such systems. The computational complexity of the presented approach is O(n m) with n being the number of tasks and m the number of clock references in the system. We apply the analysis to a real-world scenario from the automotive safety domain to confirm the computational © 2010 IEEE.

关键词： Clocks

来源：评论

学校读者我要写书评

暂无评论

The breaking point between fast-and slow-light in a degenerate two-level atomic system

引用

Chinese Physics B 2010年第6期19卷 325-329页

作者：李路明胡振燕罗斌郭弘 Department of Communication Jiangxi Electric Power Information and Communication Company CREAM Group State Key Laboratory of Advanced Optical Communication Systems and Networks (Peking University) and Institute of Quantum ElectronicsSchool of Electronics Engineering and Computer SciencePeking University

This paper investigates the breaking point between fast- and slow-light in a degenerate two-level atomic system, where fast-light can be converted to slow-light arbitrarily on a single transition line by adjusting the strength of the pumping field. An equivalent incoherent pumping rate is introduced in this simplified theoretical model which exploits the dependence of this feature. The experimental observation is presented as evidence of the breaking point where the injected power is about 0.08 mW.

关键词： degenerate two-level atomic system breaking point group velocity

来源：评论

学校读者我要写书评

暂无评论

Strong and affordable location privacy in VANETs: Identity diffusion using time-slots and swapping

Strong and affordable location privacy in VANETs: Identity d...

引用

2010 IEEE Vehicular Networking Conference, VNC 2010

作者： Eckhoff, David Sommer, Christoph Gansen, Tobias German, Reinhard Dressler, Falko Computer Networks and Communication Systems Dept. of Computer Science University of Erlangen Germany Audi Electronics Venture GmbH Gaimersheim Germany

ISBN: (纸本)9781424495252

Public acceptance, and thus the economical success of Vehicular Ad Hoc networks (VANETs), is highly dependent on the quality of deployed privacy mechanisms. Neither users nor operators should be able to track a given individual. One approach to facilitate this is the usage of pseudonym pools, which allow vehicles to autonomously switch between different identities. We extend this scheme with that of a time-slotted pseudonym pool of static size, reducing the storage and computation needs of the envisioned Intelligent Transportation System (ITS) while further improving users' privacy. In addition, we allow the exchange of pseudonyms between nodes, eliminating the mapping between vehicles and pseudonyms even for operators of the VANET. Here, we support the exchange of both the currently used pseudonym and those of future time-slots, further enhancing users' privacy. We evaluate the feasibility of our approach and back up privacy claims by performing a simulative study of the system using the entropy of nodes' anonymity sets as the primary metric. © 2010 IEEE.

关键词： Vehicular ad hoc networks

来源：评论

学校读者我要写书评

暂无评论

Adaptive beaconing for delay-sensitive and congestion-aware traffic information systems

Adaptive beaconing for delay-sensitive and congestion-aware ...

引用

2010 IEEE Vehicular Networking Conference, VNC 2010

作者： Sommer, Christoph Tonguz, Ozan K. Dressler, Falko Computer Networks and Communication Systems Dept. of Computer Science University of Erlangen Germany Electrical and Computer Engineering Dept. Carnegie Mellon University Pittsburgh PA United States

ISBN: (纸本)9781424495252

We present Adaptive Traffic Beacon (ATB), a fully-decentralized car-to-X protocol built around the central ideas of delay sensitivity and congestion awareness. From previous research findings, we see that centralized solutions, VANETs, and broadcasting based approaches each show benefits and drawbacks depending on traffic density, penetration, network utilization, and other parameters;intelligent transportation systems are therefore tuned for specific settings. In order to overcome this limitation, we developed a broadcast-based solution that has been designed to carefully use only the remaining capacity of the wireless channel. Thus, it will not influence other applications using the same radio network. ATB is adaptive in two dimensions: First, the beacon interval is adapted dynamically according to the channel quality and the importance of messages in the local knowledge base, and, secondly, the protocol can dynamically make use of available infrastructure elements. Simulation experiments demonstrate that ATB performs well in a broad range of settings. It maintains a non-congested wireless channel to prevent collisions during the data exchange. © 2010 IEEE.

关键词： Electronic data interchange

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：