检索结果-内蒙古大学图书馆

National Doctoral Academic Forum on Information and Communications Technology 2013

作者： Yuan-yuan Qiao Jie Yang Zhen-ming Lei Beijing Key Laboratory of Network System Architecture and Convergence School of Information and Communication Engineering Beijing University of Posts and Telecommunication 100876 China

Mobile Internet is one of the most popular networks in the world. Constructing the physical structure of mobile Internet is the key to modeling the network. The existing studies of fixed Internet are not suitable for mobile Internet and a deep understanding of traffic graph in mobile Internet is required. In this paper, we construct a user-server network graphs from the complete flow records of mobile Internet collected from our self-developed equipment deployed in southern China. We investigate the characteristics of the properties of Web, IM and overall traffic as the complex network point of view. Different types of traffic have different characteristics. In addition, node degree and node strength distribution of servers show that mobile network follow the power law, however, node degree and node strength distribution of users do not possess the power law property. We further study the distributions of average strength for each edge of node which follow the power law, and find the regular pattern of exponents for different applications. These discoveries could be used by the ISPs and researchers to optimize the deployment of network resources and enhance the security of the network and the Quality of Services(QoS).

关键词：

来源：评论

学校读者我要写书评

暂无评论

A NOVEL PARAMETRIC CHANNEL ESTIMATION APPROACH FOR OFDM systemS

A NOVEL PARAMETRIC CHANNEL ESTIMATION APPROACH FOR OFDM SYST...

引用

2013 International Conference on Information and network Security(2013信息与网络安全国际会议)

作者： Fang Liu Haobo Qing Kaiming Liu Yuanan Liu Gang Xie Beijing Key Laboratory of Work Safety Intelligent Monitoring School of Electronic Engineering Beij Beijing Key Laboratory of Network System Architecture and Convergence School of Information and Com

approach for orthogonal frequency-division multiplexing (OFDM) *** method is composed of two parts: estimation of channel parameters and estimation of channel *** exponentially embedded family (EEF) criterion is exploited to determine the number of channel paths as well as the multipath time *** on these parameters,channel frequency responses are ***,our scheme is computational efficient due to the needless of eigenvalue decomposition (EVD) or the estimation of signal parameters by rotational invariance technique (ESPRIT).Simulations are provided to validate the performance of our algorithm from the perspectives of channel parameter error probability (CPEP) and mean square error (MSE).

关键词： Channel Estimation OFDM Mean Square Error Exponentially Embedded Family Criterion

来源：评论

学校读者我要写书评

暂无评论

Adaptive QoS-Aware Resource Allocation for High-Speed Mobile LTE Wireless systems

Adaptive QoS-Aware Resource Allocation for High-Speed Mobile...

引用

IEEE Globecom Workshops

作者： Yifan Zhang Muqing Wu Rui Zhang Panfeng Zhou Shiping Di Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing National Railway Research & Design Institute of Signal & Communication

ISBN: (纸本)9781479928521

Resource allocation is one of the key issues in long term evolution (LTE) systems. In this paper, we propose an adaptive resource allocation scheme with quality of service (QoS) guarantees to maximize system throughput for high-speed mobile LTE systems. In this scheme, considering that channel quality indicator (CQI) might be changed in fast mobile scenarios which can reduce the system throughput, we first propose a novel CQI feedback method to achieve continue high throughput. Then we optimize the resource blocks (RB) allocation procedure under QoS requirements and adopt a more effective modulation and coding scheme (MCS) selection method to improve the system performances. Through extensive simulations, the results show that the proposed resource allocation scheme can achieve higher system throughput and better performance stability compared with some existing schemes in high-speed mobile LTE systems.

关键词： Resource Allocation CQI Feedback QoS MCS Selection High-speed Mobility LTE

来源：评论

学校读者我要写书评

暂无评论

Implementation of rate matching with low latency and little memory for LTE turbo code

引用

Journal of Information and Computational Science 2013年第13期10卷 4117-4125页

作者： He, Suqin Hu, Qiaozhi Zhang, Haijun Department of Computer Science and Technology Beijing University of Chemical Technology Beijing 100029 China Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing 100876 China

In LTE (Long Term Evolution), the high utilization for physical resources is achieved by scheduling suitable number of time frequency resource elements for one user in one subframe. This is supported by the rate matching module that selecting arbitrary number of bits from the turbo coding bit streams. In this paper, a closed-form rate matching implementation method is proposed. It derives an integrated expression which is normalized for the 3 turbo coding streams. This expression sets up a mapping relationship between the bit streams input to and the bit sequence output from rate matching module. Moreover, the expression can be applied to rate de-matching processing in the receiver end. Compared with the existing method, the rate matching method that we proposed generates low latency and requires small memory. © 2013 Binary Information Press.

关键词： Turbo codes

来源：评论

学校读者我要写书评

暂无评论

A Stochastic Cooperative MIMO Channel Model Concerning the Correlation of B-R and R-M

A Stochastic Cooperative MIMO Channel Model Concerning the C...

引用

International Conference on Cyber-Enabled Distributed Computing and Knowledge Discovery, CyberC

作者： Chang-Xing Liu Jin-Chun Gao Yuan-An Liu Gang Xie Quan Hu Beijing Key Laboratory of Work Safety Intelligent Monitoring Beijing University of Posts and Telecommunications Beijing China Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

An AF relay system usually treats the transmitting, relay, together with the receiving as equivalent channel for channel estimations. It is very important to establish a reasonable channel model to simulate the actual scene. In this paper, a novel cooperative channel model framework is proposed for cooperative multiple-input multiple-output (MIMO) wireless channels. The proposed model framework is adaptable to multiple cooperative MIMO scenarios when the relay's mode is Amplify-and-forward. Given the information of correlation coefficient of transmitting, relay and receiving and the information of Mean and variance of Rayleigh channel, we can simulate the equivalent channel. Matlab simulations show that the equivalent channel is reasonable and the presented channel model can imitate the characters of the AF channel.

关键词： MIMO Correlation Relays Channel models Wireless communication Antennas Signal to noise ratio

来源：评论

学校读者我要写书评

暂无评论

A Trust Evaluation Method for Supplier Selection

A Trust Evaluation Method for Supplier Selection

引用

IEEE International Conference on Trust, Security and Privacy in Computing and Communications (TrustCom)

作者： Xiaofeng Qiu Lei Cao Pengfei Li Liang Zhao Beijing Key Laboratory of Network System Architecture and Convergence Beijing China School of Information and Communication Engineering Beijing University of Posts and Telecommunications China NSFocus Beijing China

ISBN: (纸本)9781479914449

Trust and reputation systems play important roles in supplier selection, a topic that has been widely investigated from a business and operation point of view. However, we still lack of effective studies on supplier selection with security as the optimal target, which is a very important factor for Information and Communication Technology (ICT) systems. In response, this paper outlines a method that enables people to evaluate the relative and objective trustworthiness of the alternative suppliers. Our analysis is based solely on the original data of the vulnerabilities publicly available from OSVDB and NVD, which are impossible to tamper with. They are then interpreted by an approach that combines the Analytic Hierarchy Process (AHP) and objective analysis that enables the inference of relative trust valuations based on different evaluation indexes. A case study of five well known vendors is demonstrated with qualitative comparison based on visualization of data.

关键词： Databases Measurement Analytic hierarchy process History Security Computer architecture

来源：评论

学校读者我要写书评

暂无评论

Improved RETE Algorithm in Context Reasoning for Web of Things Environments

Improved RETE Algorithm in Context Reasoning for Web of Thin...

引用

IEEE/ACM Int'l Conference on & Int'l Conference on Cyber, Physical and Social Computing (CPSCom) Green Computing and Communications (GreenCom)

作者： Teng Gao Xiaofeng Qiu Lijuan He Mobile Life and New Media Laboratory Beijing University of Posts and Telecommunications Beijing China Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

ISBN: (纸本)9781479906314

RETE is the most efficient forward inference algorithm for the development of context-aware rule-based systems. The performance of context reasoning engines in context-aware systems depends mainly on the efficiency of the pattern matching in "Cognition-Execution Loop". Nowadays many real-world contexts from WoT (Web of Things) environments have data characteristics such as large amount, quick change and lots of constant operation, imposing a trade-off between the cost of time and space of RETE algorithm. Thus, in this paper RETE+ - an improved RETE network is proposed, capable of handling context from WoT environment, which actually includes different types of data for reasoning with new characteristics. RETE+ algorithm applies shortcut memory using LRU (Least-Recently-Used) algorithm to the matching process of alpha network and solves the problems of intensive computation with all the alpha nodes. This approach takes advantage of the LRU algorithm to select alpha nodes with the highest possibility to be executed, which considerably reduces the computation overhead. The proposed approach is applied to context reasoning engine and evaluated through contrast experiments using real-world WoT data. The case study and experimental analysis demonstrate the capability of the proposed algorithm.

关键词： Context Algorithm design and analysis Cognition Engines Indexes Random access memory Educational institutions

来源：评论

学校读者我要写书评

暂无评论

An efficient algorithm for dynamic storage allocation in cloud computing environment

引用

International Journal of Applied Mathematics and Statistics 2013年第18期48卷 254-262页

作者： Lin, Wen-Hui Lei, Zhen-Ming Liu, Jun Liu, Fang He, Gang Beijing Key Laboratory of Network System Architecture and Convergence School of Information and Communication Engineering Beijing University of Posts and Telecommunication Beijing 100876 China Technology Research Institute Aisino Corporation Beijing 100195 China

With the development of cloud computing, cloud computing cluster will need to be upgraded or replacing outdated hardware. Therefore, the cluster will evolve from the initial homogenous environment into heterogeneous environments. Hadoop is originally designed to be applied to homogeneous clusters, when the cluster goes heterogeneous, the performance of Hadoop will face a downward trend. This paper addresses the problem of how to improve the performance of Hadoop in heterogeneous environments. We study the evaluation methods of server performance and Hadoop technology. Then we present a method of evaluating node performance in cloud computing environment. Base on this method, we propose an algorithm for dynamic storage allocation that based on node performance evaluation. Experiments show that this algorithm can improve the ratio of data-local map tasks and shorten job runtime in heterogeneous Cloud Computing environment. © 2013 by CESER Publications.

关键词： Cloud computing

来源：评论

学校读者我要写书评

暂无评论

A novel metric for cache size allocation scheme in Content Centric networking

A novel metric for cache size allocation scheme in Content C...

引用

National Doctoral Academic Forum on Information and Communications Technology 2013

作者： Xiandong Cui Jiang Liu Tao Huang Jianya Chen Yunjie Liu Key Laboratory of Universal Wireless Communications Ministry of Education Beijing University of Posts and Telecommunications 100876 China Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications 100876 China

Caching scheme will change the original feature of the network in Content Centric networking (CCN). So it becomes a challenge to describe the caching node importance according to network traffic and user behavior. In this work, a new metric named Request Influence Degree (RID) is defined to reflect the degree of node importance. Then the caching performance of CCN has been addressed with specially focusing on the size of individual CCN router caches. Finally, a newly content store space heterogeneous allocation scheme based on the metric RID across the CCN network has been proposed. Numerical experiments reveal that the new scheme can decrease the routing stretch and the source server load contrasting that of the homogeneous assignment and several graph-related centrality metrics allocations.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Multi-path interests routing scheme for multi-path data transfer in Content Centric networking

Multi-path interests routing scheme for multi-path data tran...

引用

National Doctoral Academic Forum on Information and Communications Technology 2013

作者： Yan Zhang Jiang Liu Tao Huang Jianya Chen Yunjie Liu Key Laboratory of Universal Wireless Communications Ministry of Education Beijing University of Posts and Telecommunications 100876 China Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications 100876 China

Content Centric networking (CCN) is one of the most promising future network architectures. Current researches on CCN routing scheme mainly focus on finding the best single routing path and then transferring all the content chunks along this path. For an Interest packet who should have had opportunities to be routed along multiple paths to reach more repositories but only been routed along one single path due to the single path routing scheme, the problems of low utilization of the network resources and unbalance of the load of the faces and repositories are caused. This paper focuses on how to make best use of multiple paths to route the Interests, and further transfer different chunks of the content back along the paths. According to the different network-status parameters, a Multi-path Interests Routing (MIR) scheme is proposed for CCN routing, which is based on Analytical Hierarchy Process (AHP). AHP is a method for obtaining the optimized result of the Interest packets allocation. The simulation experiments have been performed to evaluate the proposed scheme in terms of a wide range of performance metrics. The results show that the proposed scheme significantly outperforms existing scheme.

关键词：

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：