GPRS技术在电力抄表领域的研究与应用

GPRS技术是一种新兴的网络通信形式,GPRS技术是随着科技的不断发展出现的,在整个GPRS技术运用中,在电力抄表领域中是十分关键的,电力抄表领域利用GPRS的终端进行资源的共享,在整个共享的过程中,需要随时的进行相关的配置,这样就可以将整个通信服务中心和客户的终端进行沟通。本文就是对GPRS技术在电力抄表领域中的应用进行分析,为相关的研究提供借鉴。     

嵌入式系统与GPRS技术在气相色谱仪中的应用

本文首先介绍了气相色谱仪的工作原理及其应用现状，然后结合实际的需要，设计了一种基于ARM嵌入式系统和GPRS技术的新型气相色谱仪。具体讲述了如何构建此嵌入式系统的软硬件平台，并给出了GPRS Modern在uClinux下的软件配置方法，最后展望了该系统的实际前景。     

基于STM32微处理器的GPRS数据传输技术的研究

为了实现用微处理器进行GPRS数据传输的应用,可以采用微处理器搭载GPRS模块并进行配置的解决方案。介绍了用STM32微处理器搭载SIM900A的GPRS模块实现数据传输,并简要描述STM32底层配置以及数据传输的实现方法。     

基于GPRS的电力监控终端网络接入方案

针对目前无线通信技术在电力监控系统中的应用,研究了一种通过GPRS网络将电力监控终端接入互联网的技术方案.该方案利用GPRS无线模块与GPRS网络间的无线信道作为物理层接口,在此之上通过PPP协议实现数据链路层,最后采用uIP软件协议栈实现精简的TCP/IP协议作为网络层和传输层.在应用层采用了自定义规约.由于协议各层次都是纯软件实现,因此本方案具有成本低廉、配置灵活的特点,并且在现场使用,效果良好.     

无线从GPRS开始

蓝牙、802.11b,这两种无线连接技术都被大家看好,但率先在国内大规模普及应用的却是 GPRS 技术。4月11日,方正公司率先推出了内置 GPRS 的笔记本电脑颐和 S2000笔记本电脑,紫光也于4月19日推出了基于移动版奔腾4处理器笔记本电脑的 GPRS 解决方案。清华紫光信息产品事业部笔记本电脑部左颖表示,采用802.11b 技术,一方面需要公司购买若干 AP(无线接入点),另一方面也需要为每一台笔记本电脑配置相应的无线网卡。两者相加,802.11b的使用成本相对较高,并不特别适合在中国现阶段的大规模应用。相对而言,GPRS 是一种无线广域网技术,其基础建设是由电信部门承担,用户只需要去电信申请,付出少许费用就可以实现任何     

基于GPRS和RF技术的远程全无线自动抄表系统

分析了现有远程自动抄表系统存在的问题:从用户电表到GPRS终端的数据是以有线方式传送,使用维护不便;提出了基于GPRS和RF技术的远程全无线自动抄表系统方案:表计完成抄表,数据通过内置射频电路nRF905传至GPRS终端,GPRS终端通过移动网关实现与Internet的连接,并将接收到的用户数据远传到抄表管理中心,完成自动抄表;介绍了nRF905射频电路的工作模式、寄存器配置和SPI操作指令,讨论了GPRS通信模块与微处理器的连接与使用,给出了nRF905在表计中的应用电路和GPRS终端的硬件结构,提供了部分参考程序.     

基于GPRS技术的随钻测井数据远程传输系统

设计了一种基于GPRS技术的随钻测井数据远程传输系统方案。首先介绍了GPRS技术在远程传输系统的应用情况,然后详细描述了基于GPRS技术的随钻测井数据远程传输系统的系统组成、业务流程和实现过程,最后阐述基于GPRS的石油钻井随钻测井数据远程传输系统应用效果。     

用于大型LED显示屏的混合直流电源

设计了一种直流电源系统,可以根据LED显示屏模块的数量进行电源输出模块的自适应配置,能够通过GPRS无线通信模块对电源参数进行远程监控与配置,并且通过专家控制算法实现了太阳能光伏、蓄电池、AC-DC的自动切换.     

GPRS技术构成和发展

GPRS是GSM移动电话系统向第三代移动通信迈进的一个重要步骤,作为叠加在数字公用陆地移动通信网GSM网络之上,GPRS网络为GSM网络用户提供高速的分组数据业务的一种新的网络。本文深入技术层面介绍了GPRS技术的发展,并探讨了GPRS网络的技术现状、技术构成、网络格局等多方面的技术问题。     

基于物联网技术的通信基站智能电源管理系统设计研究

在互联网技术的基础上,物联网技术得到了快速发展,并且已经广泛应用于通信系统等许多领域,对我国社会发展产生了重大影响。通信基站是通信系统的重要部分,要保证其正常运行,必须确保智能电源管理系统的稳定性。智能电源管理系统中的数据远程通信主要是通过通信层的第二部分实现的,同时GPRS以及4G模式是远程通信常用的方式,完成系统配置以及GPRS或者4G配置就可以实现远程通信管理。     

A method of defuzzification based on the approach of areas' ratio

The new method of defuzzification of output parameters from the base of fuzzy rules for a Mamdani fuzzy controller is given in the paper. The peculiarity of the method is the usage of the universal equation for the area computation of the geometric shapes. During the realization of fuzzy inference linguistic terms, the structure changes from the triangular into a trapezoidal shape. That is why the universal equation is used. The method is limited and can be used only for the triangular and trapezoidal membership functions. Gaussian functions can also be used while modifying the proposed method. Traditional defuzzification models such as Middle of Maxima − MoM, First of Maxima − FoM, Last of Maxima − LoM, First of Suppport − FoS, Last of Support − LoS, Middle of Support − MoS, Center of Sums − CoS, Model of Height − MoH have a number of systematic errors: curse of dimensionality, partition of unity condition and absence of additivity. The above-mentioned methods can be seen as Center of Gravity − CoG, which has the same errors. These errors lead to the fact that accuracy of fuzzy systems decreases, because during the training root mean square error increases. One of the reasons that provokes the errors is that some of the activated fuzzy rules are excluded from the fuzzy inference. It is also possible to increase the accuracy of the fuzzy system through properties of continuity. The proposed method guarantees fulfilling of the property of continuity, as the intersection point of the adjustment linguistic terms equals 0.5 when a parametrized membership function is used. The causes of errors and a way to delete them are reviewed in the paper. The proposed method excludes errors which are inherent to the traditional and non- traditional models of defuzzification. Comparative analysis of the proposed method of defuzzification with traditional and non-traditional models shows its effectiveness.     

An approach to the synthesis of fuzzy stabilization systems with a priori unknown model of an object

A method of synthesis of fuzzy stabilization systems for a broad class of dynamic objects under the assumption that the mathematical model of the object is not known a priori is proposed. The control is formulated in the form of a proportional law of adjustment as a function of a macro-variable; the square of the Euclidean norm of the phase variables is adopted as the macro-variable. An analogous variable characterizes the distance of the object from the equilibrium position. Despite the simplicity of the control law, its sign remains constant due to the fact that the macro-variable is positive-definite over the entire phase space. The switching times of the signals are determined by fuzzy identification of the system’s dynamic modes on the basis of measurement of the derivatives of the macro-variable.     

Complement of Source Equation of Elastic Line

A new notion of joint, defined in terms of the state of motor (active or locked) and type of the elastic or rigid element, gear and/or link that follows after the motor, is introduced. Special attention is paid to the motion of the flexible links in the robotic configuration. The paper deals with the relationship between the equation of elastic line equilibrium, the “Euler–Bernoulli approach” (EBA), and equation of motion at the point of elastic line tip, the “Lumped-mass approach” (LMA). The Euler–Bernoulli equations (which have for a long time been used in the literature) should be expanded according to the requirements of the motion complexity of elastic robotic systems. The Euler–Bernoulli equation (based on the known laws of dynamics) should be supplemented with all the forces that are participating in the formation of the elasticity moment of the considered mode. This yields the difference in the structure of Euler–Bernoulli equations for each mode. The stiffness matrix is a full matrix. Mathematical model of the actuators also comprises coupling between elasticity forces. Particular integral of Daniel Bernoulli should be supplemented with the stationary character of elastic deformation of any point of the considered mode, caused by the present forces. General form of the elastic line is a direct outcome of the system motion dynamics, and cannot be described by one scalar equation but by three equations for position and three equations for orientation of every point on that elastic line. The choice of reference trajectory is analyzed. Simulation results are shown for a selected robotic example involving the simultaneous presence of elasticity of the gear and of the link (two modes), as well as the environment force dynamics.     

3 Laser transmission joining in microtechnology

The laser is a joining tool which is particularly suitable for the application in microtechnology. The process variant laser transmission joining can be used both for welding thermoplastics and bonding of silicon and glass. The investigations presented in this paper cover detailed examinations of both processes. Concerning laser transmission welding of plastics it is examined how far the content of carbon black in the material influences the formation of the weld seam. It is shown that the optical depth of penetration, the weld seam width as well as the formation of the weld morphology differ with varying content of carbon black. Selective laser radiation bonding (SLB) is a novel method for joining silicon and glass based on the transmission heating of the interface of both joining partners and the thermo-chemical principles of silicon direct bonding. SLB shows advantages in reference to the thermal load of sensitive components like sensors and to the selectivity of the joining geometry. In this study the principle method of SLB and the latest advances like the integration of the thermal process control in the laser processing head will be presented. Also experimental test results of the process with constant laser power and thermal process control and the comparison of them will be shown.An erratum to this article can be found at     

Remote sensing of spring phenology in boreal regions: A free of snow-effect method using NOAA-AVHRR and SPOT-VGT data (1982-2004)

Measurements of spring phenological dates in boreal regions using NDVI can be affected by snowmelt. This impacts the analysis of interannual variations in phenology and the estimates of annual carbon fluxes. For these two objectives, snowmelt effect must be removed from the phenological detection. We propose a methodology for determining the date of onset of greening in the 1982-2004 period using SPOT-VEGETATION (VGT) and NOAA Advanced Very High Resolution Radiometer (AVHRR) data. From 1998 onwards, the date of onset of greening is taken as the date at which the Normalized Difference Water Index (NDWI), calculated from SPOT-VGT near and short-wave infrared bands, starts increasing. This index decreases with snowmelt but increases with vegetation greening. For the 1982-2001 period, the date of onset of greening is the date at which AVHRR-NDVI equals a pixel specific threshold (PST), determined using the results of the NDWI method in the years common to the two datasets. The methods are validated using in situ measurements of the dates of leaf appearance. RMSE of 6.7 and 7.8 days, respectively, is found using NDWI-VGT and PST-NOAA methodologies, and the difference between the two methodologies in the common years is small. Very importantly, the dates are not biased. The interannual variations of the 23-year spring phenology dataset on the study area in northern Eurasia are analysed. In average over the study area, an advance of 8 days and a delay of 3.6 days are, respectively, found over the periods 1982-1991 and 1993-2004. These results confirm and complete previous studies about the greening trend, remove the uncertainty due to snow, and may improve carbon budget calculations.     

Spark平台下聚类算法的性能比较

通过实验,从运行时间、加速比、可扩展性和规模增长性4个方面比较了 Spark平台中3种典型的聚类算法即K-means聚类算法、二分K-means聚类算法和高斯混合聚类算法 的性能。实验结果表明:1)随着节点个数的增加,3种算法对百兆以上规模数据集聚类的运行时间明显减少;2)当数据集规模大于500MB时,3种算法的加速比均有明显提高,且随着节点个数的增加,加速比近似于线性增长;3)3种算法的可扩展性随着节点个数的增加而降低,当数据集规模大于500MB时,相对于K-means和高斯混合算法,二分K-means算法的可扩展性最差;4)当数据集规模大于100MB时,高斯混合算法的规模增长性远高于K-means和二分K-means算法。     

Mr. Twinn’s bombes

This article discusses the history and design of the special versions of the bombe key-finding machines used by Britain’s Government Code & Cypher School (GC&CS) during World War II to attack the Enigma traffic of the Abwehr (the German military intelligence service). These special bombes were based on the design of their more numerous counterparts used against the traffic of the German armed services, but differed from them in important ways that highlight the adaptability of the British bombe design, and the power and flexibility of the diagonal board. Also discussed are the changes in the Abwehr indicating system that drove the development of these machines, the ingenious ways in which they were used, and some related developments involving the bombes used by the U.S. Navy’s cryptanalytic unit (OP-20-G).     

协作机器人的构型分析研究

针对协作机器人的构型分析研究,得出了偏置是影响机器人构型的一个重要因素。首先,对现有典型协作机器人的构型进行分析,通过构型间的内在联系与演化过程得到构型之间的差异。然后利用构型之间的差异引出了偏置的定义,并通过偏置对关节运动范围的影响将其分为S型偏置和Y型偏置。最后以全局性能指标、工作空间体积指标和灵活工作空间指标为性能评价标准,对iiwa、Sawyer、Yumi三种典型构型的性能进行了仿真。通过对比分析可知,偏置的存在使构型的全局性能和工作空间体积性能降低,但对灵活工作空间性能有提高作用。结果表明偏置是影响机器人性能的重要因素,该分析研究为协作机器人的构型设计提供了理论依据。     

Overview of ATM networks: functions and procedures

The purpose of this paper is to present an overview of the ATM technique. The basic principles of the ATM transfer technique, the B-ISDN layered protocol reference model, as well as the architecture and the main functions of the ATM network, are described in this tutorial. In particular, we present the main characteristics of the ATM technique, the structure of the ATM cell, the functions which deal with the protection from errored cells (HEC procedure) and the identification of the boundaries of the ATM cells (cell delineation and scrambling). The VP/VC concept is explained in detail, and the main principles and functions of the three lowest layers (Physical, ATM and Adaptation) of the B-ISDN layered protocol reference model are surveyed. The issue of Quality of Service parameters in ATM networks is reviewed, and the problem of the allocation of the network resources in response to user demands, as well as the problems of congestion control, Usage Parameter Control (UPC) and traffic modelling in ATM networks, are assessed. Finally, we present ‘possible’ sets of traffic characterization parameters, and show how possible B-ISDN sources can be modelled according to the basic on-off ATM traffic source model.