西太平洋国家及地区间电信流空间结构研究

文章较细致地回顾了自1970年以来国家间电信流研究的成果和发展过程,评述了相关的研究方法,利用大量的现实数据、借助数理统计方法,透视了1990～2002年西太平洋12个国家及地区间电信流空间结构的演变及其空间作用特点,展望了该地区国家及地区间电信流节点结构的发展趋势.

西太平洋地区国家间电信流影响因子及其作用分析

电信流是一种存在于空间反映人类的通信活动,电信流的大小是反映一个国家经济发展水平与利用ICTs技术的主要依据。本文在回顾自1970年以来国家间电信流研究的成果和发展过程的基础上,从模型进程中透视了电信流影响因子指标体系的变化,提出影响国家间电信流的八类因子:电信设备、经济发展、国际贸易、国际旅游、国家联系、政府促进、文化联系、空间结构。本文以西太平洋地区为例,运用数学方法对各类影响因子进行分析、排序, 并创新性地从分析结果中将各种物质流对电信流的作用归结为4种形式:增强、替代、协同和衍生作用。

恒流脉冲电信号控制策略的研究

研制出一套恒流脉冲电信号源,该设备有高精度输出脉冲稳流功能,具有响应速度快,恒流精度高、能长期稳定工作等优点。本设备采用STM32微处理器进行控制,其中包含微控制器控制模块、运放电路模块、脉冲产生模块、电源模块、报警模块、按键模块及显示等模块。针对在不同负载情况下电流无法实现稳定恒流的问题,提出模糊PI恒流控制策略,使得恒流脉冲信号源负载电流均为具有一定频率的恒定值。最后,通过实验验证可得加入模糊PI恒流控制方法后,该设备的输出电流为恒定值,符合某些系统参数要求,并可根据实际需求更改输出电流频率与幅值。

协同环境下电信物流发展的推进策略研究

针对电信物流现有的问题,运用协同理论分析了电信物流的协同界面,并对仓储管理、配送管理、库存管理、信息系统、增值服务和管理体系等六方面内容存在的问题进行了深入分析,最后提出了协同环境下电信物流发展的推进策略,为实现电信协同物流的仓储网络集中化、配送模式一体化、库存管理统一化、信息系统互补化、增值物流体系完整化和管理体系规范化提供了参考。

电信诈骗案件之电子数据取证分析思路

电信诈骗案件为非接触性犯罪,没有时间和地域的限制,犯罪对象涉及面广,打击难度大,没有确定的嫌疑对象,证据的获取和固定非常难,破案技术性要求非常高。电子数据取证在侦查办案中发挥的作用日趋重要,而电信诈骗案件与一般案件的电子数据取证又存在很大不同,需通过调取大量的银行流水、通话清单、上网记录等电子数据分析,才能顺藤摸瓜锁定嫌疑对象。

Application of a cost-sensitive method for churn prediction in telecommunication industry

To deal with the data mining problem of asymmetry misclassification cost, an innovative churn prediction method is proposed based on existing churn prediction research. This method adjusts the misclassification cost based on the C4. 5 decision tree as a baseline classifier, which can obtain the prediction model with a minimum error rate based on the assumption that all misclassifications have the same cost, to realize cost-sensitive learning. Results from customer data of a certain Chinese telecommunication company and the fact that the churners and the non-churners have different misclassification costs demonstrate that by altering the sampling ratio of churners and non-churners, this cost-sensitive learning method can considerably reduce the total misclassification cost produced by traditional classification methods. This method can also play an important role in promoting core competence of Chinese telecommunication industry.

A Robust Low Power Chaos-Based Truly Random Number Generator

This paper presents a low power,truly random number generator （TRNG） based on a simple chaotic map of the Bernoulli shift,which is extended to remain robustness in implementation. The map is realized by switched-current techniques that can fully integrate it in a cryptosystem on a chip. A pipelined architecture post-processed by a simple XOR circuit is used to improve the entropy. The TRNG is fabricated in an HJTC 0.18μm CMOS mixed signal process,and the statistical properties are investigated by measurement results. The power consumption is only 1.42mW and the truly random output bit rate is 10Mbit/s.

CLOSE-LOOP DESIGN OF PULSE POWER SUPPLY FOR ELECTRICAL DISCHARGE MACHINING

The dynamic performance and the stability are essential for a system. A new circuit topology used for electrical discharge machining (EDM) power and made up of complex-pulse (voltage-pulse and current-pulse) is presented. The large-signal model of it is also derived. Based on the comprehensive analysis of the system model, the compensator is designed to make the system match better and to improve its dynamic performance and the stability under perturbations. Finally, the design methods and the analysis are verified by simulation and experimental results.

A Signal-Flow Driven Automatic Physical Synthesis Methodology for Analog Circuits

This paper introduces a novel automatic physical synthesis methodology for analog circuits based on the signal-flow analysis.Circuit analysis sub-system adopts the newly advanced methodology,circuit topology analysis,and circuit sensitivity analysis to generate layout constraints and control performance degradations.Considering the heuristic information about signal-flow,complexity of the methodology is less than the pure performance-driven methodology.And then these constraints are implemented in device generation,placement,and routing sub-systems separately,which makes the different constraints be satisfied at most easily implemented stages.Excellent circuit performance obtained by the methodology is demonstrated by practical circuit examples.

A novel shapelet transformation method for classification of multivariate time series with dynamic discriminative subsequence and application in anode current signals

Classification of multi-dimension time series(MTS) plays an important role in knowledge discovery of time series. Many methods for MTS classification have been presented. However, most of these methods did not consider the kind of MTS whose discriminative subsequence was not restricted to one dimension and dynamic. In order to solve the above problem, a method to extract new features with extended shapelet transformation is proposed in this study. First, key features is extracted to replace k shapelets to calculate distance, which are extracted from candidate shapelets with one class for all dimensions. Second, feature of similarity numbers as a new feature is proposed to enhance the reliability of classification. Third, because of the time-consuming searching and clustering of shapelets, distance matrix is used to reduce the computing complexity. Experiments are carried out on public dataset and the results illustrate the effectiveness of the proposed method. Moreover, anode current signals(ACS) in the aluminum reduction cell are the aforementioned MTS, and the proposed method is successfully applied to the classification of ACS.

Effect of salt gradients on DNA translocation through solid-state nanopores

Aiming at the issues of controlling the translocation speed of DNA through a solid-state nanopore and enlarging the signal-to-noise ratio of ionic current modulation, which are challenges for the application of nanopore technology in DNA detection, salt concentration gradients are applied across the nanopore to investigate their influence on the DNA translocation time and signal-to-noise ratio. Experimental data demonstrates that, in symmetric concentration conditions, both the current blockade and dwell time for A-DNA translocation through a solid-state nanopore increase along with potassium chloride concentration. When the concentration in the trans chamber is decreased from 1 to 0.1 mol/L, keeping the concentration of the cis chamber at 1 mol/L, the normalized current blockade is found to be increased by one order. The increased dwell time and enhanced signal-to-noise ratio are achieved with salt gradients across the nanopore, which can improve the sensitivity when detecting DNA samples.

基于PSoC的矿用传感器模拟电路设计

本文设计了一款基于PSoC的矿用传感器模拟电路,由PSoC最小系统板、数模转换模块、电流环模块三部分组成。该电路可以输出高达四路0-3.3V或0-5V电压、八路4-20m A电流环信号,以及62路开关量信号。该矿用传感器模拟电路可以模拟常用的矿用传感器的输出模拟信号,数字信号。操作方便,可通过简单的配置生成所需要的多种传感器输出的预处理信号,避免了购买高昂的传感器。

Modeling and Characterizing Internet Backbone Traffic

With enormous growth of the number of Internet users and appearance of new applications, characterization of Internet traffic has attracted more and more attention and has become one of the major challenging issues in telecommunication network over the past few years. In this paper, we study the network traffic pattern of the aggregate traffic and of specific application traffic, especially the popular applications such as P2P, VoIP that contribute most network traffic. Our study verified that majority Internet backbone traffic is contributed by a small portion of users and a power function can be used to approximate the contribution of each user to the overall traffic. We show that P2P applications are the dominant traffic contributor in current Internet Backbone of China. In addition, we selectively present the traffic pattern of different applications in detail.

Complete Localization of HVDC Back-to-Back Project Realized

The first completely localized DC back-to-back project for asynchronous interconnection between Northwest and Central China plays an important role in realizing national power grid interconnection, spurring indigenous manufacturing industries and promoting DC transmission equipment. Insisting on the principle of autonomous innovation, this project was based on domestic forces in every aspect, from engineering organization, system design, equipment completion, engineering design, equipment manufacturing and procurement to construction and debugging. By passing through strict quality control, intermediate supervision and acceptance test and assessment, the project has been proved up to world advanced level.

Thermo Tank Temperature Control System Based On STM32

This paper introduced a thermo tank temperature control system based on STM32. Firstly, the temperature acquisition is real- ized by the high-lxecision electrical bridge based on constant current source. Then the augmented PID algorithm realized by software is adopteff But-terworth filter is used to convert the o.aput PWM of STM32 to current signal which is used to control the seniconductor control rectifier to adjust the temrature. Calibration check and practical application both indicated that the system was reliable, high-precision, practicable and could meet reality needs.

Linking the health data system in the U.S.:Challenges to the benefits

In order to improve patient care in the United States there,the government made a mandate called HIE(Health Information Exchange).This order was created from the belief that sharing digital health in-formation between,across,and within health communities will improve one's healthcare experience across their lifespan.Patient health information,i.e.the personal health record,should be shareable between healthcare providers;such as private practice physicians,home health agencies,hospitals and nursing care facilities.Most of the U.S.hospitals now have electronic health records,however,with a lack of standards for structuring health information and unified communication protocols to share health information across providers,only a small percentage of U.S.hospitals engage in computerized HIE.In order to understand barriers and facilitators in the U.S.of HIE adoption,we reviewed the published research literature between 2010 and 2015.Our search yielded 664 articles from Medline,PsychInfo,Global health,InSpec,Scopus and Business Source Complete databases.Thirty-nine articles met our inclusion criteria.This article presents the compiled organizational and end user barriers and facilitators along with suggested methods to achieve continuity of care through HIE.

Discrete element method analysis of lateral resistance of fouled ballast bed

The lateral resistance of sleeper plays an important role in ensuring the stability of a railway track, which may change in the operation of railway, due to the fouling in the ballast bed. In this work, discrete element method was adopted to investigate the effect of fouling on the lateral resistance of sleeper. The shape information of ballast was captured by method of three-dimensional vision reconstruction. In order to calibrate the mechanical parameters and verify the models, a lateral resistance field test was carried out by using a custom-made device. The contact force distributions in the different parts of sleeper as well as the interaction between ballast and sleeper were discussed in depth. The results show that fouling of ballast bed evidently reduces the lateral resistance of sleeper and the decreasing degree is also related to the fouled position of ballast bed, in the order of shoulder > bottom > side.Therefore, the effect of fouling, especially the fouling in the ballast shoulder, on the lateral resistance of sleeper, should be taken into account in ballast track maintenance work.

Searching for Flavor-Changing Neutral-Current Signals via e^+e^-(γγ)→th_t^0 in Topcolor-Assisted Technicolor Model

In the context of the top-color-assisted technicolor （TC2） model, the flavor-changing neutral-current （FCNC） interaction induced by the top-higgs （hOt） are predicted at tree level. We study the relevant processes of e＋e-（γγ）→tcht0 at the International Linear Collider （ILC）. It is found that these rare processes production rates can be enhanced significantly in the TC2 model. Especially for the process γγ→tcht0, the total cross section will reach a few fb in the reasonable parameter space. We also calculate the distributions of transverse momenta, pseudo-rapid and invariant mass of the top-higgs. In view of the main decay modes of top-higgs for mho 〈 2mr, we find that there will be several hundreds FCNC events produced at the ILC with annually integral luminosity of 500 fb-1. Due to the clean background, such FCNC signals can possibly be detected at the ILC.

Non-inverting buck-boost DC-DC converter based on constant inductor current control

The hysteresis control combined with PWM control non-inverting buck-boost was proposed to improve the light load efficiency and power density.The constant inductor current control(CICC)was established to mitigate the dependence on the external components and device variation and make smooth transition between hysteresis control loop and pulse width modulation(PWM)control loop.The small signal model was deduced for the buck and boost operation mode.The inductor current slope control(ICSC)was proposed to implement the automatic mode transition between buck and boost mode in one switching cycle.The results show that the converter prototype has good dynamic response capability,achieving 94%efficiency and 95%peak efficiency at full 10 A load current.

Design of EPS Testing System Based on LabVIEW2012

The article designed a set of automatic test system of automobiles EPS based on LabVIEW, which can collect current signal and torque signal when emergency braking. It consists of two parts： hardware and software. Hardware includes sensors,condition circuits, data acquisition card and your computer. Software-related programs, including an analysis of acquisition signal processing and storage display.The system is stable and reliable by contrast verification.