面向地震网络计算的网格工作流管理系统

针对国家地震网络计算应用系统的需求,将工作流技术引入地震网络计算,实现了国家地震网格工作流管理系统.该系统能够将地震领域的部分专业应用定义为一个工作流来为用户提供服务,对系统中的基本服务进行调度,通过网格中间件进行执行,并对任务进行监视和管理.论述了该系统的框架及相关技术,通过对现有的地震行业典型应用的流程分析,构造出一个工作流实例,简化了类似应用服务的开发过程.     

基于成本-效益优化的BRT规划方案评价研究

针对快充纯电动快速公交（bus rapid transit,BRT）系统的运营效果评价问题,提出基于快充纯电动公交车辆运行特性与BRT运营特点的评价方法.首先,分析快充纯电动公交车辆在BRT中的适用性,从运营车辆性能、设施水平、乘客服务水平、经济效益等角度出发,建立包含燃油车辆替换率、动力电池衰减率、充电设施供需平衡关系等9项细化指标的快充纯电动BRT运营效果评价指标体系;其次,采用灰色聚类方法,构建快充纯电动BRT运营效果评价模型;最后,以金华市国内首条纯电动BRT线路为例,进行运营效果评价.与实际运营情况调查结果对比后发现,相比传统BRT运营效果评价方法,该方法更能真实、有效地反映纯电动BRT的实际运营效果.

     

利用F聚类分析实现逆向工程中点云数据的分割

提出了一种点云数据分割方法,即在模糊数学中F聚类分析的理论基础上,利用数据点的三维坐标、法矢量和曲率构成八维特征向量,将具有类似几何特征的点集聚为一类,从而实现点云数据分割,为逆向工程中产品造型提供了一种新思路。实验证明了此方法的可行性,且方法比较简单,易于实现。     

湖南常见辣椒品种游离氨基酸主成分分析及综合评价

游离氨基酸参与辣椒中风味物质的合成,其种类及含量与辣椒品种密切相关.采用高效液相色谱-串联质谱法对湖南常见大红椒、青尖椒、螺丝椒、小米椒、小红椒、大青椒6种辣椒的游离氨基酸进行分析,明确不同辣椒品种游离氨基酸组成差异,以期为合理开发和利用辣椒资源提供理论依据.结果表明:6种辣椒中共检出24种游离氨基酸,其中青尖椒、螺丝...     

高可用群集多处理技术的原理、规划及配置

在金融、通信等服务领域必须保证关键性业务对外稳定、持续地进行,群集技术(双机)为此提供了可靠的保证.首先介绍了群集的概念,然后基于IBM的AIX系统的高可用群集多处理技术(hacmp for aiz),对群集的网络、管理软件、单点故障、资源组接管策略等进行了详细分析,最后以一个客户端连接到应用、应用连接到数据库的3层客户/服务器(C/S)结构的金融应用系统为例,对群集的规划及配置进行了比较详细的讨论,并给出互相接管模式的双机配置规划和相关应用及数据库的起停脚本.     

Enhancing the performance of the FETI method with preconditioning ¶techniques implemented on clusters of networked computers

 The FETI domain decomposition method for solving large-scale problems in computational structural mechanics involves the solution of an interface problem, which is handled by a Preconditioned Conjugate Projected Gradient (PCPG) algorithm. Two preconditioners are widely used to accelerate the convergence of the iterative PCPG algorithm: the optimal Dirichlet preconditioner and the economical lumped preconditioner. The Dirichlet preconditioner is computationally more efficient than the lumped preconditioner for ill-conditioned problems, but needs additional storage for the stiffness matrices of the subdomains' internal degrees of freedom (d.o.f.). In this study a new set of PCPG preconditioners is presented by providing approximate expressions to the inverse iteration matrix of the PCPG algorithm. The resulting approximate Dirichlet preconditioners are obtained by using instead of the whole stiffness matrix of the internal d.o.f. in each subdomain the following alternatives: a diagonal scaling matrix, a SSOR type matrix or an incomplete Cholesky factorization matrix. The computational behavior and performance of the proposed PCPG preconditioners is evaluated using an implementation of the FETI method on a cluster of ethernet-networked PCs running the message passing software PVM. It is demonstrated that the FETI method equipped with the approximate Dirichlet preconditioners leads for a number of large-scale problems to faster and less storage demanding overall solutions than with either Dirichlet or lumped preconditioner. Received: 28 December 2001 / Accepted: 22 August 2002     

材料切削性能的模糊综合评判

介绍了一套材料加工参数智能推理系统的研究。重点讨论了模糊理论在该系统中的运用，采用模糊综合评判、模糊聚类原理，根据用户输入材料的物理机械性能，快速确定材料的切削加工性能。将材料按切削加工性能等级分类可简化材料切削参数推理，有利于新材料切削参数的确定。     

An efficient algorithm for generalized SS/TDMA scheduling with satellite cluster and intersatellite links

We consider the satellite cluster scheduling problem, which is one of the most interesting problems in the satellite communication scheduling area. This problem is known to be NP-complete, and a couple of heuristic algorithms have been developed. In this paper, we suggest another algorithm for this problem which has the same computational complexity as the best existing one and provides much better solution quality. Extensive computational simulation results are reported.     

基于Web集群许可控制算法的自适应机制

指出了MRED算法的局限性，并利用一个二阶指数许可函数来设计非线性自适应控制算法，避免了单一静态阈值参数的不足，实现了许可控制的平滑化．实验仿真结果表明：该算法有效提高了集群利用率，避免了集群负载崩溃情况，提高了系统的稳定性与可靠性．     

Nb2O5-Based Oxide Ceramics and Single Crystals-Investigation of Dielectric Properties

The behavior of enhancements of dielectric constant of Nb₂O₅ through small substituents of TiO₂ is of interest. The ceramics of these solid solutions were prepared by the conventional mixed oxide method. Single crystal fibers were grown by the Lase r-Heated Pedestal Growth (LHPG) technique, which is considered to be a powerful tool for rapid growth of high-melting temperature oxides and incongruent melting compositions. The dielectric properties as function of temperature (-180°C to 180°C) and frequency (1 KHz to 1 MHz) were measured. The direct-current (dc) electric field dependence of the dielectric constant has been studied. The results show the strong dielectric dispersion which exists in a large frequency range which implies that the relaxation process involved is not of a Debye type. A relaxation distribution can be therefore expected. The influence of the cluster size dispersion is one assumption. Thus, the data of dc bias field dependence of the dielectric constant has been analyzed by the modified Devonshire relation including a cluster term giving the fitted parameters: cluster sizes distribution and their polar cluster polarization.

^aOn leave from the Petroleum and Petrochemical College, Chulalongkorn University, Thailand.