Distributed Consensus-Based K-Means Algorithm in Switching Multi-Agent Networks

This paper discusses a distributed design for clustering based on the K-means algorithm in a switching multi-agent network, for the case when data are decentralized stored and unavailable to all agents. The authors propose a consensus-based algorithm in distributed case, that is, the doubleclock consensus-based K-means algorithm(DCKA). With mild connectivity conditions, the authors show convergence of DCKA to guarantee a distributed solution to the clustering problem, even though the network topology is time-varying. Moreover, the authors provide experimental results on various clustering datasets to illustrate the effectiveness of the fully distributed algorithm DCKA, whose performance may be better than that of the centralized K-means algorithm.     

高强度锌基合金摩擦特性的试验研究

本文用铸造高强度锌基合金 ZA27和添加有少量合金元素的 ZA27S,在油充分润滑条件下,与青铜 ZQSn6-6-3、ZQSn10-1进行了摩擦、磨损特性的对比性试验研究。结果表明,摩擦系数随载荷的变化并非为定值。载荷增加时,摩擦系数下降,其中以 ZQSn10-1下降最多,ZQSn6-6-3变化最小。轻载时锌基合金的摩擦、磨损特性与 ZQSn6-6-3相近,明显优于 ZQSn10-1;重载时又与 ZQSn10-1相似,远比 ZQSn6-6-3好,尤以 ZA27S 最佳。此外,锌基合金比锡青铜具有更好的跑合性和建立油膜的能力。     

试论生态分区的概念,等级单位和划分依据：以云南省为例

生态分区即为不同等级的区域生态系统的确定。它表示陆地生物圈或其某一部分的生态系统空间格局。不同等级的区域生态系统空间格局有不同的尺度和形成背景。区域生态系统有一定的形态结构和动态功能。本文根据云南实际，提出三个等级的分区单位，说明其含义，并提供了全省的生态区和生态亚区的系统并予以简要说明。     

用于管道焊缝检测的激光超声系统

针对石油管道焊缝检测中被测样品粗糙,作业环境恶劣等问题,基于光折变晶体内双波混合干涉原理,研制了高频激光超声测振仪,结合激光超声的激励技术,设计了一种可用于检测石油管道表面及内部焊缝缺陷的激光超声检测系统.利用该系统分别对缺陷在表面和内部的管道焊缝试块进行了超声激励和检测实验.实验结果表明,该系统能有效地分析出被测样品表面以及内部缺陷的位置以及相应深度,检测分辨率达到0.01 mm,缺陷位置检测误差控制在2%以内.该检测系统结构紧凑可靠,操作简便,开发的高频激光超声测振仪能工作在管道焊缝检测的常见作业环境(70~75 d B低频环境噪声),具有一定的适用性.     

PWM型降压式DC-DC变换器中的混沌现象

对工作在电感电流连续模式下的PWM型降压式DC-DC变换器进行了研究,采用连续采样、恒频的PWM控制环调节DC-DC变换器的输出电压。通过理论分析与实践电路两方面证实了DC-DC变换器在革些特定的电路参数下会出现多脉冲、倍周期分叉及混沌等现象。     

Performance evaluation for damping controllers of power systems based on multi-agent models

This paper proposes a multi-layer multi-agent model for the performance evaluation of power systems, which is different from the existing multi-agent ones. To describe the impact of the structure of the networked power system, the proposed model consists of three kinds of agents that form three layers: control agents such as the generators and associated controllers, information agents to exchange the information based on the wide area measurement system (WAMS) or transmit control signals to the power system stabilizers (PSSs), and network-node agents such as the generation nodes and load nodes connected with transmission lines. An optimal index is presented to evaluate the performance of damping controllers to the system's inter-area oscillation with respect to the information-layer topology. Then, the authors show that the inter-area information exchange is more powerful than the exchange within a given area to control the inter-area low frequency oscillation based on simulation analysis. This work was supported in part by the National Natural Science Foundation of China under Grants Nos. 50707035, 50595411, 60425307, 60221301, and 50607005, in part by the 111 project (B08013) and Program for Changjiang Scholars and Innovative Research Team in University (IRT0515) and in part by the Program for New Century Excellent Talents in University (NCET-05-0216).     

细胞培养法增殖油桐尺蠖NPV工艺条件

探讨了用油桐尺蠖成虫卵巢细胞系 (Bs4 84细胞系 )增殖油桐尺蠖核型多角体病毒 (BsNPV)的若干工艺条件。结果显示 ,病虫血淋巴在不同温度条件下保存 ,4℃一个月内 ,- 2 0℃和液氮中 4～ 6个月内 ,病毒仍具有实用水平的活性 ;感染后的细胞培养物 ,用超声波破碎优于液氮冻融法 ;感染后的细胞培养物培养2 4 ,36 ,4 8,6 0 ,72h取样 ,超声波破碎 ,培养 6 0h的样品具有较高病毒滴度 ;于感染后第 4 ,5,6 ,7d取样 ,细胞不破碎 ,第 5～ 6天病毒滴度达较高值。     

徐州师范大学三维虚拟校园设计与实现

利用三维景观建模软件GoogleSketchUp和GIS开发软件ArcGISEngine,建立了徐州师范大学三维虚拟校园系统,该系统除具有一般三维浏览功能外,还具有一些GIS功能．     

Distributed Consensus-Based <Emphasis Type="Italic">K</Emphasis>-Means Algorithm in Switching Multi-Agent Networks

This paper discusses a distributed design for clustering based on the K-means algorithm in a switching multi-agent network, for the case when data are decentralized stored and unavailable to all agents. The authors propose a consensus-based algorithm in distributed case, that is, the double-clock consensus-based K-means algorithm (DCKA). With mild connectivity conditions, the authors show convergence of DCKA to guarantee a distributed solution to the clustering problem, even though the network topology is time-varying. Moreover, the authors provide experimental results on various clustering datasets to illustrate the effectiveness of the fully distributed algorithm DCKA, whose performance may be better than that of the centralized K-means algorithm.