基于图形化编程的HVDC以太网103双网通信设计

为了实现高压直流输电（High Voltage Direct Current Transmission，缩写为HVDC）控制保护系统与保护信息子站之间快速可靠的数据交互，提出一种基于图形化编程的HVDC以太网103双网通信设计方法。该方法针对IEC60870-5-103标准定义的串口103通信进行扩展，提出以太网103双网通信方案，提高通信实时性和可靠性；此外，该方法将应用程序与底层通讯处理程序相分离，采用标准的IEC61131图形化设计语言，开发出高度封装的底层通讯处理模块与用户功能模块相融合的图形化编程方法，软件编程简单高效，系统运行及调试信息可在线监测。基于该方法在锡泰和扎青等HVDC工程的实验数据表明，该方法具有可靠性高，开发进度快，运行维护方便的特点，对于实现控制保护系统与保护信息子站快速可靠的数据交互具有重要的应用价值。     

The Principles of Eliminating Pulsating Torque in Current Source Inverter Induction Motor Systems

The problem of reducing the pulsating torque in current source inverter induction motor systems is investigated. Two typical approaches presented in recent publications are analyzed by making clear 1) the correlation among the current harmonics and the torque harmonics, and 2) the conceptual contradiction existing between these two approaches. By synthesizing the analyzed results, fundamental principles for treating the current harmonics and torque harmonics are established. In addition, the method for evaluating the degree of torque ripple is described, along with a proposed criterion for torque ripple content. By applying this criterion to these two approaches, objective estimates of degree of torque pulsations, which were unfeasible so far, are now made possible.     

Time domain analysis of the weighted distributed order rheological model

This paper presents the fundamental solution and relevant properties of the weighted distributed order rheological model in the time domain. Based on the construction of distributed order damper and the idea of distributed order element networks, this paper studies the weighted distributed order operator of the rheological model, a generalization of distributed order linear rheological model. The inverse Laplace transform on weighted distributed order operators of rheological model has been obtained by cutting the complex plane and computing the complex path integral along the Hankel path, which leads to the asymptotic property and boundary discussions. The relaxation response to weighted distributed order rheological model is analyzed, and it is closely related to many physical phenomena. A number of novel characteristics of weighted distributed order rheological model, such as power-law decay and intermediate phenomenon, have been discovered as well. And meanwhile several illustrated examples play important role in validating these results.     

Ginzburg-Landau Analysis on the Superconductivity in TlNi<Subscript>2</Subscript>Se<Subscript>2</Subscript>

Based on a two-band isotropic Ginzburg-Landau theory, we study the magnetic properties of the recently observed superconducting crystal TlNi₂Se₂. Our exact solution of upper critical field reproduces the experimental data in a broad temperature range. It directly underlies the multi-gap superconductivity in this crystal. We also show that the effective mass of the electron for one band is about 20m _e while that of the other band is only 0.6m _e. This semi-heavy-fermion feature can qualitatively explain the experimental value of the Kadowaki-Woods ratio in TlNi₂Se₂.     

Design and implementation of a trusted monitoring framework for cloud platforms

Virtualization is a pillar technology in cloud computing for multiplexing computing resources on a single cloud platform for multiple cloud tenants. Monitoring the behavior of virtual machines (VMs) on a cloud platform is a critical requirement for cloud tenants. Existing monitoring mechanisms on virtualized platforms either takes a complete VM as the monitoring granularity, such that they cannot capture the malicious behaviors within individual VMs, or they focus on specific monitoring functions that cannot be used for heterogeneous VMs concurrently running on a single cloud node. Furthermore, the existing monitoring mechanisms have made an assumption that the privileged domain is trusted to act as expected, which causes the cloud tenants’ concern about security because the privileged domain in fact could not act as the tenants’ expectation. We design a trusted monitoring framework, which provides a chain of trust that excludes the untrusted privileged domain, by deploying an independent guest domain for the monitoring purpose, as well as utilizing the trusted computing technology to ensure the integrity of the monitoring environment. Moreover, the feature of fine-grained and general monitoring is also provided. We have implemented the proposed monitoring framework on Xen, and integrated it into OpenNebula. Our experimental results show that it can offer expected functionality, and bring moderate performance overhead.     

Adapting grid computing environments dependable with virtual machines: design, implementation, and evaluations

Due to its potential, using virtual machines in grid computing is attracting increasing attention. Most of the researches focus on how to create or destroy a virtual execution environments for different kinds of applications, while the policy of managing the virtual environments is not widely discussed. This paper proposes the design, implementation, and evaluation of an adaptive and dependable virtual execution environment for grid computing, ADVE, which focuses on the policy of managing virtual machines in grid environments. To build a dependable virtual execution environments for grid applications, ADVE provides an set of adaptive policies managing virtual machine, such as when to create and destroy a new virtual execution environment, when to migrate applications from one virtual execution environment to a new virtual execution environment. We conduct experiments over a cluster to evaluate the performance of ADVE, and the experimental results show that ADVE can improve the throughput and the reliability of grid resources with the adaptive management of virtual machines.     

统一混沌系统的混合同步在图像加密中的应用

研究参数已知的统一混沌系统的混合同步现象,在这种同步模式中,系统的一部分状态正相同步,而其它状态反相同步,设计了一个简单的单向线性反馈控制器,提出实现混合同步的充分条件.采用近似熵算法对耦合的混沌同步系统的复杂性研究结果表明,与单一混沌系统相比,本文实现的同步系统具有较高的复杂度.最后,基于该同步系统实现了一个图像加密方案,加密方案采用典型的图像加密框架,混乱阶段采用2D标准映射方案,扩散阶段采用像素的位置信息进行像素值替换,仿真实验结果与安全性分析表明,该算法加密效果良好,安全性较高.     

湖北宣恩县农村饮水安全工程建设管理探讨

湖北省宣恩县因地理条件特殊和人口居住分散等特点,饮水安全问题突出。通过对宣恩县农村饮水安全基本状况进行分析,发现饮水安全工程建设和管理还存在一些问题,针对当地的特点,提出了做好规划设计、加强质量监督及运行管理等对策建议。     

实时数据流在钢铁生产过程监控系统中的应用

为了解决现有钢铁企业生产过程中存在的实时控制系统与企业级ERP系统之间的信息孤岛、实时数据保存困难和过程管理粗糙等问题,在基于实时数据流的基础上,设计了钢铁生产过程实时监控系统,并将实时数据与关系型数据结合,实现了工业生产的有效实时监控,使实时数据在过程能力管理领域中得以应用,达到精细和精确化管理,提高了钢铁产品质量,为企业获得了良好的经济效益.     

基于融合网络播存机制的数据发布模式研究

针对互联网易拥塞和广播网单向性的缺点,面向大规模信息发布的需求,提出基于融合网络播存机制的数据发布架构.以自适应互补为主要原则,根据文件缺失的程度动态地选择通过广播系统或互联网进行补全,形成数据播发/交互闭环系统.通过仿真与传统数据发布模式进行对比,分析计算该架构数据发布模式的公共信息推送能力,结果表明,该架构在大规模数据发布方面的资源开销较广播系统、互联网系统平均低约两个数量级.