基于支持向量机的计算资源反馈调度

在实时控制系统(RTCS)中,计算资源一般受限。由于诸多不确定性因素和工作负载的动态变化,系统总是运行在不可预期的开放环境中。为保证系统的稳定运行,提出了一种基于支持向量机(SVM)的计算资源反馈调度方法。它周期性地监测系统计算资源,通过SVM在线预测,得到各个控制回路的下一个采样周期,从而实现系统计算资源的动态分配。通过仿真实验验证了该反馈调度方法的性能,并与理想情况、传统开环调度方法进行了比较,显示了其优越性。     

基于细胞因子网络协同进化的Web服务合成方法

借鉴生物神经内分泌免疫系统的协同进化机制,基于细胞因子网络平台提出了Web服务的合成方法.在细胞因子网络调控下的生物实体代理Web服务,构成为一个带有条件的米兰机单元,Web服务的合成可以转换为米兰机进化过程.生物实体通过消息匹配和条件约束形成细胞因子网络,Web服务的合成通过生物实体细胞因子网络支持.在服务协同进化过程中可以动态调整其合成的服务,完成服务的动态自组织合成和管理等工作.仿真结果表明该方法在环境动态变化时具有适应性.     

控制流图上支配关系计算方法的分析与实现

支配关系在数据流分析和静态单赋值等程序分析和优化中应用很广泛.采用位向量表示支配结点集合,描述了采用迭代法计算控制流图上支配结点集合的算法,在支配结点集合的基础上讨论了对直接支配结点、支配边界结点的计算方法,并在NPB和SPEC2000测试集上进行了测试.测试结果表明:控制流图的构建占用了过程内支配关系计算的几乎一半时间;对于不包含goto语句的结构化程序,迭代算法一般只需迭代2次.     

基于加权模糊支持向量描述的旋转机械故障分类

基于支持向量数据描述良好的分类性能,针对旋转机械故障诊断中故障样本获取的特点,提出了基于正负类样本的加权模糊支持向量数据描述多类分类器,不仅考虑了正类样本,而且也充分考虑了负类样本对分类结果的影响.利用模拟故障样本对系统进行了实验,结果表明提出的方法在系统中具有良好的分类能力.     

一种新颖隶属度函数的模糊支持向量机

传统的支持向量机(SVM)训练含有外部点或噪音数据时,容易产生过拟合(over-fitting)。通过模糊隶属度函数来降低外部点或被污染数据的选择。本文提出了一种新的核隶属度函数,这种新的隶属度函数不仅依赖于每个样本点到类型中心的距离,还依赖于该样本点最邻近的K个其他样本点的距离。实验结果表明了具有该隶属度函数的模糊支持向量机的有效性。     

Pi演算对图灵机的表达

为了研究Pi演算的表达能力,我们试着用它来表达图灵机。研究结果表明,只要对Pi演算进行一定的的扩展,即引入某些函数符号,允许对发送的名字作一定的运算,就可以用Pi演算的规约来表达图灵机的运算过程。     

永磁同步电机空间矢量控制方法设计实现

针对永磁同步电机结构复杂、模型非线性从而导致难以控制的问题,通过推导建立了其基于矢量控制下的简化的数学模型,仅通过控制电机交轴电流就可对其进行控制.在此基础上,对交轴电流进行调节,将其转换为基于两相静止坐标系下的电压矢量,设计了以两相静止坐标系下的参考电压作为输入变量的空间矢量控制方法,借助于数字信号处理器(DSP)的强大功能对系统进行实现,给出了所设计的硬件结构图及软件流程图,并进行了仿真验证,且效果良好,证明了所建模型的正确性和系统的可行性.     

Integrating scientific modeling and supporting dynamic hazard management with a GeoAgent-based representation of human–environment interactions: A drought example in Central Pennsylvania, USA

Recent natural disasters indicate that modern technologies for environmental monitoring, modeling, and forecasting are not well integrated with cross-level social responses in many hazard-management systems. This research addresses this problem through a Java-based multi-agent prototype system, GeoAgent-based Knowledge System (GeoAgentKS). This system allows: (1) computer representation of institutional regulations and behavioral rules used by multiple social institutions and individuals in cross-level human–environment interactions, (2) integration of this representation with scientific modeling of dynamic hazard development, and (3) application of automated reasoning that suggests to users the appropriate actions for supporting cooperative social responses. This paper demonstrates the software architecture of GeoAgentKS and presents such an integrated approach by modeling the drought management processes in Central Pennsylvania, USA. The results show that it is possible to use GeoAgentKS to represent multilevel human–environment interactions and to use those interactions as input to decision making in hazard management.     

决策支持系统在跨部门电子政务工程中的实现

决策支持系统合理应用到跨部门电子政务工程中不但可以降低大量的人力和财力成本,还会为电子政务中半结构化或非结构化问题提供重要的决策支持。文章提供了一种跨部门电子政务工程中决策支持系统技术架构的设计,为决策支持系统在跨部门电子政务工程中的实现提供了一种方法。     

Surface Control and Electrical Tuning of MXene Electrode for Flexible Self-Powered Human–Machine Interaction

MXene materials emerge as promising candidates for energy harvesting and storage application. In this study, the effect of the surface chemistry on the work function of MXenes, which determines the performance of MXene-based triboelectric nanogenerator (TENG), is elucidated. First-principles calculations reveal that the surface functional group greatly influences MXene work function:  OH termination reduces the work function with respect to that of bare surface, while  F and  Cl increase it. Then, work functions are experimentally determined by Kelvin probe force microscopy. The MXene prepared by gentle etching at 40 °C for 48 h (GE_40/48) has the largest work function. Furthermore, an electron-cloud potential-well model is established to explain the mechanism of electron emission-dominated charge transfer and assemble a triboelectric device to verify experimentally its conclusions. It is found that GE_40/48 has the best performance with a 281 V open-circuit voltage, 9.7 µA short-current current, and storing 1.019 µC of charge, which is consistent with the model. Last, a patterned TENG is demonstrated for self-powered human–machine interaction application. This finding enhances the understanding of the inherent mechanism between the surface structure and the output performance of MXene-based TENG, which can be applied to other TENG based on 2D materials.