MPE: a mobility pattern embedding model for predicting next locations

World Wide Web - The wide spread use of positioning and photographing devices gives rise to a deluge of traffic trajectory data (e.g., vehicle passage records and taxi trajectory data), with each...     

The analysis and comparison of two novel kinds of focusing elements as reflectors

In this article, two novel kinds of focusing elements as reflectors are analyzed and compared. One is the grooved Fresnel zone plate reflector with continuous phase‐correcting. The other called subzone paraboloid reflector, has the profile that consists of a series of paraboloids. Their diffraction efficiencies and bandwidths are described. The two elements still preserve the advantages of Fresnel zone plates, namely, low profile, high efficiency, and simple fabrication. Two dual‐reflector antennas using the proposed focusing elements as the main reflectors are simulated and the results show that these antennas have good radiation performances. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:101–108, 2015.     

Specific emitter identification for satellite communication using probabilistic neural networks

Electromagnetic signal emitted by satellite communication (satcom) transmitters are used to identify specific individual uplink satcom terminals sharing the common transponder in real environment, which is known as specific emitter identification (SEI) that allows for early indications and warning (I&W) of the targets carrying satcom furnishment and furthermore the real time electromagnetic situation awareness in military operations. In this paper, the authors are the first to propose the identification of specific transmitters of satcom by using probabilistic neural networks (PNN) to reach the goal of target recognition. We have been devoted to the examination by exploring the feasibility of utilizing the Hilbert transform to signal preprocessing, applying the discrete wavelet transform to feature extraction, and employing the PNN to perform the classification of stationary signals. There are a total of 1000 sampling time series with binary phase shift keying (BPSK) modulation originated by five types of satcom transmitters in the test. The established PNNs classifier implements the data testing and finally yields satisfactory accuracy at 8 dB(±1 dB) carrier to noise ratio, which indicates the feasibility of our method, and even the keen insight of its application in military.     

掌握油气生产发展规律 提高自动化应用水平

油气生产的自动化过程控制是转变生产方式,发展油气生产依靠的主要科学技术之一.结合油气生产发展的特征,全面总结了中国石油近几年自动化技术应用取得的成绩,针对不同的生产特征,确定了自动化控制系统的不同功能和构成特点,提出了自动化系统应用中存在的问题和发展方向.     

WC/Cu复合材料制备及其高温性能

用机械合金化法结合冷变形，制备了WC／Cu复合材料，研究了冷变形后复合材料的组织特征和高温退火时韵性能变化。结果表明：烧结后的材料经冷变形，组织呈显著纤维状，WC颗粒弥散分布，密度明显提高，达到理论密度的99．2％；复合材料经600～900℃高温退火，强度和硬度略有下降，塑性则有大幅提高；900℃退火时未发生明显的再结晶，界面结合良好；所制备的WC／Cu复合材料有优良的综合性能。     

岩石物理横波速度曲线计算技术

横波速度是地震勘探中的重要参数。针对实际生产中缺乏横波速度测井曲线资料，利用经验公式计算精确度不高的问题，通过对横波速度计算理论模型的研究分析，选择Blot-Gassman模型法，利用岩石矿物成分、流体成分、孔隙度及密度等测井曲线进行横波速度测井曲线的计算，并对横波速度计算技术和流程进行研究。在实际工区进行了横波速度曲线计算，计算结果与实测横波吻合程度较高，误差小于10％，该技术在储层和流体识别预测的应用中取得了较好效果。     

Component-relevancy and characterization results in multistatesystems

Two new versions of component relevancy for multistate structure functions are introduced. They are compared with some existing component-relevance conditions and their general properties are investigated. Based on the two relevance conditions, two component-importance measures for multistate systems are defined; they are most appropriate for comparing components when a certain type of system improvement is considered. Series and parallel structures are characterized within the L-superadditive and L-subadditive structure functions by imposing the two new relevance conditions     

面向WCDMA建立网络管理信息模型

分析了WCDMA移动通信网网管系统管理框架，在此基础上提出采用公共对象请求代理体系结构（CORBA）建立网管系统信息模型的优势，给出WCDMA网管系统的信息模型，同时介绍了对象管理组（OMG）接口描述语言（IDL）。     

基于PⅢ工控机VI测控系统远程控制研究

虚拟仪器（VI）将计算机采集测试分析引入到电子测量领域，用数字化和软件技术极大地提高了测量的灵活性。而VI远程测控系统是网络技术、通信技术一计算机虚拟技术结合的产物。远程控制技术能够使操作突破地域的限制，已在网络环境下PⅢ工控机上实现。