情报科学新域的创新与突破——评邱均平等著的《网络数据分析》

在印本文献时代,文献计量学的出现与发展,为情报学的发展作出了极为重要的贡献.早在20多年前,正是米哈依诺夫的<科学交流与情报学>、严怡民的<情报学概论>[1]等著作,以及<情报学报>、<情报科学>杂志中大量出现的文献计量方法,展示了现代情报学的精美与严谨的理论形象,推动了我国情报学的迅速发展,使情报科学成为图书情报学人争相投入的领域,文献计量学更是热极一时.

网络传播与网络信息计量学研究的新突破——评邱均平教授等的《网络数据分析》

从创新点、学术地位、社会影响、写作特点、内容体系、应用范围等方面对邱均平教授等的《网络数据分析》一书进行介绍和评价,认为该书思路清晰、内容丰富,并创造性地将信息计量学和科学计量学的最新理论与定量的方法引入网络数据分析和网络传播研究,是网络传播与网络信息计量学研究方面的难得之作。

一部具有创新性、系统性与实用性的力作——评《网络数据分析》

文章对邱均平教授与他的博士研究生合著的《网络数据分析》从创新性、系统性与实用性三个方面进行了评论,认为这是国内网络信息计量学领域中的奠基性著作。

Mining and Modelling the Dynamic Patterns of Service Providers in Cellular Data Network Based on Big Data Analysis

Understanding the dynamic traffic and usage characteristics of data services in cellular networks is important for optimising network resources and improving user experience.Recent studies have illustrated traffic characteristics from specific perspectives,such as user behaviour,device type,and applications.In this paper,we present the results of our study from a different perspective,namely service providers,to reveal the traffic characteristics of cellular data networks.Our study is based on traffic data collected over a five-day period from a leading mobile operator's core network in China.We propose a Zipf-like model to characterise the distributions of the traffic volume,subscribers,and requests among service providers.Nine distinct diurnal traffic patterns of service providers are identified by formulating and solving a time series clustering problem.Our work differs from previous related works in that we perform measurements on a large quantity of data covering 2.2 billion traffic records,and we first explore the traffic patterns of thousands of service providers.Results of our study present mobile Internet participants with a better understanding of the traffic and usage characteristics of service providers,which play a critical role in the mobile Internet era.

Data service oriented networking analysis of TD-LTE system

The development of mobile internet and internet of things brings the vigorous developing data service, which increases need of bandwidth sharply. Operators strive to develop the data service oriented LTE(long term evolution)technology, especially TD-LTE (time division-LTE) technology adopting the spectral asymmetric. This paper analyzed details of TD-LTE system networking, and studied the feasibility of TD-LTE and TD-SCDMA(TD-synchronous code division multiple access) system with the same spectrum. At last, the paper provided suggestions on networking of TD-LTE system.

A weighted selection combining scheme for cooperative spectrum prediction in cognitive radio networks

A weighted selection combining （WSC） scheme is proposed to improve prediction accuracy for cooperative spectrum prediction in cognitive radio networks by exploiting spatial diversity. First, a genetic algorithm-based neural network （GANN） is designed to perform spectrum prediction in consideration of both the characteristics of the primary users （PU） and the effect of fading. Then, a fusion selection method based on the iterative self-organizing data analysis （ISODATA） algorithm is designed to select the best local predictors for combination. Additionally, a reliability-based weighted combination rule is proposed to make an accurate decision based on local prediction results considering the diversity of the predictors. Finally, a Gaussian approximation approach is employed to study the performance of the proposed WSC scheme, and the expressions of the global prediction precision and throughput enhancement are derived. Simulation results reveal that the proposed WSC scheme outperforms the other cooperative spectrum prediction schemes in terms of prediction accuracy, and can achieve significant throughput gain for cognitive radio networks.

Germany＇s Energy Transition and the European Electricity Market： Mutually Beneficial？

Germany＇s energy system is in transition towards less nuclear, lower carbon emissions and more renewables. Notwithstanding widespread neglect of its European dimension, this Energiewende will further exacerbate current network fluctuations due to the significant increase in wind and solar power. Key data from Denmark show that this transition will soon bring the German national power system to its limits for absorbing the resulting intermittency, and increase the need for more cross-border power transfers. Yet network analysis of import/export data shows that Germany＇s position in the European power system is contrary to the Danish case. The need for a European solution for Germany＇s energy transition will therefore soon become evident. In order to establish the necessary infrastructure, the Energiewende needs hence to be guided by an economic approach designed to prevent further fractures in the Internal Electricity Market. Constructive negotiations with neighbouring countries on market designs and price signals will be important preconditions. The article emphasizes the still neglected European paradox of Germany＇s energy transition and presents working examples and possible solutions to uphold electricity supply in Europe＇s power house.

The measurement and model construction of complex permittivity of vegetation

The complex permittivity of targeted objects is an important factor that influences its microwave radiation and scattering characteristics.In the quantitative research of microwave remote sensing,the study of the dielectric properties of the vegetation to establish the relationship between its specific physical parameters and complex permittivity is fundamental.In this study,six categories of vegetation samples were collected at the city of Zhangye,a key research area of the Heihe watershed allied telemetry experimental research.The vector network analyzer E8362B was used to measure the complex permittivity of these samples from 0.2 to 20 GHz by the coaxial probe technique.The research focused mainly on the corn leaves,and an empirical model was established between the gravimetric moisture and the real/imaginary parts of complex permittivity at the main frequency points of microwave sensors.Furthermore,the empirical model and the classical Debye-Cole model were compared and verified by the measured data collected from the Huailai County of Hebei Province.The results show that the newly- established empirical model is more accurate and more practical as compared to the traditional Debye-Cole model.