支持向量机在变压器故障诊断中的应用研究

变压器是电力系统的重要设备,其工作状态直接影响电网的稳定性.因此,研究变压器故障诊断技术以及如何提高变压器的运行维护水平具有重要的意义.经过大量的实践发现,常用的三比值法存在缺编码、编码边界过于绝对和故障诊断准确率不理想等缺陷.为弥补上述不足,提出了基于支持向量机的变压器故障诊断方法.诊断实例表明,采用该方法进行变压器故障诊断准确率得到较大提高.     

一种改进的类比估算方法及案例研究

在软件成本估算中类比估算所要解决的主要问题之一是如何定义合适的相似度,有必要充分利用模型信息提高估算精度.提出一种改进的类比估算方法,定义模型属性信息空间上由第一类曲线积分计算的弧长为相似度.在此基础上开发了改进的类比估算工具ImpAnalogy,并且进行了案例研究.结果表明改进后的类比估算方法有效地提高了估算精度.     

基于服务的Agent社会组织研究

Web Service应用上的人工架构模式成为了其被高度重用的瓶颈。通过Agent对Web Service的封装能极大地改善WebService资源在应用上的主动性及智能性。针对Web Service封装后所形成的Agent服务,给出了基于服务本体及Agent服务描述语言(ASDL)的服务发现方法,并在此基础上给出了基于服务的Agent社会组织机制。实际应用证明方法可行有效。     

基于OpenGVS半潜船操作模拟器视景系统的研究

为了满足半潜船作业人员学习和培训的需要,有必要在航海模拟器大环境下研发半潜船操作模拟器仿真系统。以船舶静力学为基础,实现了半潜船装载重大件货物的过程的动态稳性计算,以Visual C++6.0和OpenGVS场景管理软件为开发平台,研制开发了半潜船操作模拟器应具备的视景系统。该仿真系统实现了视点的转移和跟踪,通过设置在半潜船的驾驶台、甲板及外部三个虚拟相机,实时动态显示半潜船各种运动的状态,同时实现了半潜船操作模拟器几个模块间的相互通信,取得了很好的效果。     

支持JSR286和WSRP2.0规范的Portlet协作的设计

JSR286规范定义了本地Portlet之间的协作方式,WSRP2.0规范定义了远程Portlet之间的协作方式,但两者并未深入涉及远程Portlet和本地Portlet之间的协作问题,降低了Portlet的交互能力。针对这点不足,在WSRP2.0规范定义的事件分发及状态分发等协作机制基础上,设计了一个消费者门户主导的联邦协作框架。在该框架中,通过协作信息转换和协作服务作为中介,通过消息队列进行消息存储、消息验证和消息处理,实现了Portlet容器和代理容器的松散耦合,并支持远程Portlet和远程Portlet之间、远程Portlet和本地Portlet之间、本地Portlet和本地Portlet之间的协作。该框架与JSR286规范和WSRP2.0规范兼容,满足WSRP2.0模块的可插拔性,并具有良好的可扩展性和可移植性。     

基于层次分析法的测试用例可复用性度量研究

对测试用例的可复用性度量进行研究,构建测试用例可复用性评估模型,通过分析转化得到易于度量的层次分析模型。通过层次分析模型构建权重比较矩阵,再进行相关属性的度量,并可进一步开展自动的测试用例可复用性度量。     

一种基于数据挖掘的量化新增需求代码量的分析方法

需求演化频繁发生于软件项目中,并且在很大程度上影响着软件项目的成败。对需求演化的影响进行准确的估算,将有效地帮助项目管理者降低软件项目失败的风险。其中,如何量化新增需求对软件项目的影响,是一个尤其难以解决的问题。提出一种基于数据挖掘的需求演化影响的量化分析方法,将新增需求与软件项目已有需求进行聚类,对于聚类结果进行分析,能够相对准确地量化新增需求将要产生的代码量。     

On-demand minimum cost benchmarking for intermediate dataset storage in scientific cloud workflow systems

Many scientific workflows are data intensive: large volumes of intermediate datasets are generated during their execution. Some valuable intermediate datasets need to be stored for sharing or reuse. Traditionally, they are selectively stored according to the system storage capacity, determined manually. As doing science on clouds has become popular nowadays, more intermediate datasets in scientific cloud workflows can be stored by different storage strategies based on a pay-as-you-go model. In this paper, we build an intermediate data dependency graph (IDG) from the data provenances in scientific workflows. With the IDG, deleted intermediate datasets can be regenerated, and as such we develop a novel algorithm that can find a minimum cost storage strategy for the intermediate datasets in scientific cloud workflow systems. The strategy achieves the best trade-off of computation cost and storage cost by automatically storing the most appropriate intermediate datasets in the cloud storage. This strategy can be utilised on demand as a minimum cost benchmark for all other intermediate dataset storage strategies in the cloud. We utilise Amazon clouds’ cost model and apply the algorithm to general random as well as specific astrophysics pulsar searching scientific workflows for evaluation. The results show that benchmarking effectively demonstrates the cost effectiveness over other representative storage strategies.     

On fuzzy renewal processes for fuzzy random variables and extended theorems

In this paper, we construct fuzzy renewal processes involving fuzzy random variables. We first extend the renewal processes to the fuzzy renewal processes where interarrival times, rewards, and stopping times are all fuzzy random variables. According to these fuzzy renewal processes, we then extend some theorems of renewal processes to those in fuzzy renewal processes. These are elementary renewal theorem, asymptotic expected average reward, and Wald's equation. In each part, we also give examples for applications. © 2010 Wiley Periodicals, Inc.     

Global existence and nonexistence for degenerate parabolic equations with nonlinear boundary flux

In this paper, by constructing various kinds of sub- and super-solutions and using the basic properties of M-matrix, we give the necessary and sufficient conditions of global existence for nonnegative solutions to a degenerate parabolic system with completely coupled boundary conditions, which generalize the recent results of, for instance, Cui [Z. Cui, Critical curves of the non-Newtonian polytropic filtration equations coupled with nonlinear boundary conditions, Nonlinear Anal. 68 (2008) 3201–3208], Zhou–Mu [J. Zhou, C. Mu, Algebraic criteria for global existence or blow-up for a boundary coupled system of nonlinear diffusion equations, Appl. Anal. 86 (2007) 1185–1197] etc.