Use of a software monitor in the validation of an analytic computer system model

The use of a software monitor in validating a cyclic server multiprogramming model of OS/360 is presented. Following a brief development of the analytic model, a sampling software monitor designed to track CPU and channel I/O activity in OS/360 is described. A procedure for fitting the model to the system based on measurements obtained by the monitor is developed and comparative results of the adjusted model and the actual system are presented for validation of the model principles.     

基于Agent的客户机/服务器模型的设计与实现

在对Agent技术、多Agent技术以及Client/Agent/Server（客户机/代理/服务器）模式的理论分析基础上,指出了传统C/S结构的不足,提出了基于Agent的两层Agent/Server模式.然后基于该模式,给出了一个Agent/Server框架,简称ASFtame.由于引入了先进的FIPA标准和多Agent开发思想,ASFrame能充分发挥移动Agent的移动性,从而提高了应用系统的伸缩性和智能性.     

专用浏览器/服务器系统模型的设计与实现

在客户机／服务器和浏览器／服务器系统模型的基础上，结合多层客户机／服务器系统模型，提出了专用浏览器／服务器系统模型，并给出了一个实例。该模型使得浏览器可通过数据库服务器直接与数据库通信，具有开发成本低、性能更高、安全性更好。最后还给出了专用浏览器／服务器系统模型的其它解决方案。     

C/S模式企业应用向RIA迁移的研究及实现

针对C/S模式和B/S模式企业应用的不足,探讨了一种C/S模式企业应用向RIA模式迁移的解决方案。通过采用增加软件部署服务器、改造原有系统的数据传输组件和客户端、重用原有系统数据访问和业务处理组件等措施,成功实现了C/S模式应用系统向RIA的升级重构,最小化了企业应用的升级成本。     

基于排队论的自动化立体仓库AGV调度效率分析

为了提高自动化立体仓库系统AGV的输送效率，在对整体系统进行介绍后，运用排队论理论对自动化立体仓库AGV的调度系统进行建模，得到M／G／1模型，在对该模型理论分析后，就该模型的调度效率进行了分析。     

无耦合PCNN频域特性分析

脉冲耦合神经网络（PCNN）模型具有脉冲调制和耦合连接特性,广泛应用于数字图像处理领域。然而现有PCNN模型的研究都是从时域或图像本身包含信息角度分析参数与模型特性之间的关系,无法全面解释参数对模型特性的影响。从PCNN模型的迭代方程出发,利用离散系统频域分析方法从频域角度对无耦合PCNN模型进行分析,揭示无耦合PCNN模型的动态门限子系统具有低通特性,并确定网络参数a_E的选取范围,同时通过对脉冲发放时刻公式进行推导,得到参数v_E的选取范围。采用傅里叶变换方法分析单个神经元的脉冲发放频率特性和动态门限衰减频率特性,解释无耦合PCNN模型的参数对频域特性的影响。仿真实验结果验证了该理论分析结论的正确性,从频域角度理解无耦合PCNN模型的参数与模型特性之间的关系,为挖掘PCNN模型特性提供一种新的方法。     

含有摩擦间隙迟滞的机械臂关节建模方法

为了提高机器人关节建模精度,提出了一种同时考虑摩擦、间隙和迟滞的综合建模方法.将关节分为高速轴和低速轴两部分,采用GMS (generalized Maxwell-slip)方法构建了减速器高速轴和低速轴的摩擦模型:采用Preisach模型来描述两部分迟滞模型中的线性特性,采用多项式方法来描述迟滞特性中的非线性刚度以满...     

基于键合图的汽车悬架系统建模与仿真

键合图是一种图形工具,它可以清晰形象地描述系统内部的能量结构.文中给出了功率键合图理论对汽车1/4、1/2悬架系统建模的详细方法,建立了1/4、1/2悬架的键合图模型.对1/2悬架键合图模型进行仿真时,文中没有采用传统的推导状态方程方法,而是将键合图模型按照键合图与方块图的转化关系直接转为方块图模型,再利用MATLAB软件的Simulink工具箱对1/2悬架的方块图进行建模仿真.给出了仿真模型,得到了较好的仿真结果.验证了键合图结合方块图理论对系统建模和分析的优越性.     

基于超爱尔兰分布的自相似网络排队模型研究

现有网络的业务流研究表明,多种通信业务中普遍存在自相似特性,但是如何对自相似业务流进行建模和分析一直是个难解问题。基于超爱尔兰拟合算法,建立了到达为泊松分布,服务时间为超爱尔兰分布的M/HErD/1/K自相似排队模型,推导得到呼叫损失概率、平均排队队长等排队性能的解析解。在实际业务环境下和传统的M/M/1/K排队模型进行了仿真对比,结果表明M/HErD/1/K模型不仅可有效表征业务流的快挂业务特性,而且能仿真出该网络在业务负荷较重时潜在的运营风险,对实际网络运营管理具有重要的指导作用。     

Entropic-FV修正模型预测聚合物体系溶胀行为

Entropic-FV（EFV）修正模型是对原模型的自由体积分数项进行修改而获得,前者与后者具有相同的统计力学基础,且表达式简单,无需增加模型参数。将其用于聚乙二醇／甲醇二元体系中组分活度的计算,或与UNIQUAC-HB模型结合对聚乙烯醇膜／乙二醇／水和聚氨酯／正己烷／苯三元体系的溶胀平衡组成进行预测,并与EFV和原修正模型的预测结果以及文献值进行比较,结果显示该模型预测的准确度最高、稳定性较好。     

Scalability of hybrid programming for a CFD code on the Earth Simulator

The Earth Simulator (ES) is an SMP cluster system. There are two types of parallel programming models available on the ES. One is a flat programming model, in which a parallel program is implemented by MPI interfaces only, both within an SMP node and among nodes. The other is a hybrid programming model, in which a parallel program is written by using thread programming within an SMP node and MPI programming among nodes simultaneously. It is generally known that it is difficult to obtain the same high level of performance using the hybrid programming model as can be achieved with the flat programming model.

In this paper, we have evaluated scalability of the code for direct numerical simulation of the Navier–Stokes equations on the ES. The hybrid programming model achieves the sustained performance of 346.9 Gflop/s, while the flat programming model achieves 296.4 Gflop/s with 16 PNs of the ES for a DNS problem size of 256³. For small scale problems, however, the hybrid programming model is not as efficient because of microtasking overhead. It is shown that there is an advantage for the hybrid programming model on the ES for the larger size problems.     

模拟移动床过程的混杂系统建模方法

模拟移动床过程中连续变量与离散变量并存,属于典型的混杂系统.对此,从混杂系统的角度出发,在简化模拟移动床过程平衡扩散模型的基础上,探索一种新的模型表示方法.通过应用一些近似处理方法,导出了完整的一类混合整数动态模型,并通过对一种混杂非线性的Benchmark模型的仿真实验验证了所建立的混合逻辑动态模型的有效性.     

基于核和信息域的区间灰数Verhulst 模型

针对传统Verhulst模型的建模对象仅局限于实数序列这一缺陷,对Verhulst模型进行了拓展.首先,对“灰度不减”公理进行延伸,得到了“信息域不减”的推论;然后,构建核序列的Verhulst模型,并以信息域不减推论为依据、以核为中心推导区间灰数上(下)界的时间响应式;最后,通过实例演示了模型的计算步骤.所进行的研究对于丰富和完善灰色预测模型理论体系、拓展灰色预测模型的应用范围具有积极意义.     

Analysis of an Industrial System

Studying industrial systems by simulation enables the designer to study their dynamic behaviour and to determine characteristics of the system. Unfortunately, simulation also has some disadvantages. These can be overcome by using formal methods. Formal methods allow a thorough analysis of the possible behaviours of a system, parameterised system analysis and a modular approach to the analysis of systems. We present a case study in which a model of an industrial system is studied in a formal way. For this purpose, the model is first specified and simulated using the CSP-based executable specification language . The model is translated into a model in the process algebra CRL. This enables us to give a correctness proof of the parameterised model and to study the model in isolation.     

风/光互补发电场优化设计模型

针对复杂的风/光互补发电场优化设计问题,首次提出了一种新的风/光互补发电场优化设计模型.在分析了现有研究的基础上,给出了适合于风/光互补发电场部件发电量计算的计算模型,归纳了设计时各部件的数量和类型选择的约束关系,最后综合给出了一种新的适合于风/光互补发电场优化设计的模型.     

Development of models of optimal complexity using self-organization theory

An organized approach is considered for determining the best functional (usually polynomial) form of a mathematical model for a complex system using the minimum ofa priori information. It is necessary to know only the list of the variables that may possibly take part in the model, the corresponding table of data, and the general criterion that the model is to satisfy (e.g., the prediction is to be accurate or the model is to be unbiassed). The computer, with the help of a special organized sifting of models, uses the self-organization principle to find a unique model of optimal complexity.     

Simulation of alternative binding modes in a structure-based QSAR study of HIV-1 protease inhibitors

We have used a published set of inhibitors of HIV-1 protease to build a COMBINE-type structure-based QSAR model with good predictive ability (r² = 0.90, q² = 0.69). Since the compounds in the training series exhibit most of their structural variability on one-half of the pseudosymmetrical binding cavity and only one binding orientation was explored for each molecule, the model describes mainly the effect of the structural changes on interactions involving only one-half of the binding cavity (pockets S1′ and S2′). Thus, the model cannot be expected to give accurate predictions for new compounds exhibiting structural variation in both halves. The model does in fact show a tendency to underpredict slightly the biological activity of the molecules in the external test set. In an attempt to improve the quality of the model, both possible orientations of the ligands are now considered so that structural variation takes place in all binding pockets. One possibility would have been to build an additional set of complexes with the inhibitors docked in a reversed orientation. The alternative we have explored, however, consists of manipulating the data matrix describing the interaction energies so that each row is duplicated and the order of the variables in the duplicated rows is swapped between subunits. This simple approach has produced a new model that is similar in quality to the original model (r² = 0.89, q² = 0.64) but lacks the tendency to underpredict the activity of the compounds in the external set. Moreover, since equivalent residues are assigned equivalent weights, the model is insensitive to ligand orientation and is easier to interpret.     

运载火箭大姿态调姿段全数值飞行仿真

以国产CZ系列运载火箭为研究对象,建立了大姿态飞行段全量数学模型,包括控制方程、箭体运动以及数字校正网络和非线性开关函数.并利用Matlab/Simulink仿真环境对大姿态调姿系统进行了全数值仿真研究.在仿真过程中,采用模块化思想建模,先将系统分解为一系列功能相对独立的子系统,再进行仿真模型集成,构建出大姿态调姿系统的总体模型.还对仿真模型进行了验证,分析了其在给定输入条件下的输出情况,仿真结果表明:模型建立正确,调姿系统的性能指标均满足技术要求,能够较好的完成调姿功能.最后对仿真模型进行了精度分析并提出了进一步研究方向.     

网格环境下CAD模型的建立与共享

在研究三维模型检索技术的基础上,将网格技术及P2P技术融合在三维模型检索中,提出了一种新的建立与共享机制,给出了相应的设计模型,实现了CAD模型库的异构数据资源整合.对OGSA-DAI实现CAD模型的建立、特征提取、相似性匹配以及P2P技术实现CAD模型共享做了详细的阐述.该设计模型比传统的C/S模式或B/S模式更具有开放性与实用性,提高了CAD模型设计的效率.