浅议建筑给排水施工中节水节能技术的应用

现代我国建筑工程领域广泛地应用了对水源及能源等自然资源的节约型新工艺,其也是以后建筑事业长久发展的新方向,且已在目前的建筑工程给排水项目施工作业环节中得到了广泛的运用。资源节约型技术在建筑工程给排水项目构筑工序中所发挥出的效能具备双面性,不但可以大力提升建筑工程给排水施工中对各类自然资源的运用效率,而且还可以推进建筑施工智能化操作的快速实现。基于此,本文就建筑给排水项目施工环节中节水节能新工艺的具体运用展开了深入的探讨。     

Amplification of high-order rainbows of a cylinder with an elliptical cross section

The intensity of high-order rainbows for normally incident light and certain rotation angles of a cylinder with an elliptical cross section is greatly amplified with respect to the intensity for a circular cross-sectional cylinder. The amplification is due to a number of the internal reflections occurring past the critical angle for total internal reflection, and the effect is especially strong for odd-order rainbows, beginning with the third order. Experimentally, the fourth- and the fifth-order rainbows of a nearly elliptical cross-sectional glass rod were observed and analyzed.     

National Institute of Standards and Technology high-accuracy cryogenic radiometer

A high-accuracy cryogenic radiometer has been developed at the National Institute of Standards and Technology to serve as a primary standard for optical power measurements. This instrument is an electrical-substitution radiometer that can be operated at cryogenic temperatures to achieve a relative standard uncertainty of 0.021% at an optical power level of 0.8 mW. The construction and operation of the high-accuracy cryogenic radiometer and the uncertainties in optical power measurements are detailed.     

浅谈校园网的安全隐患及防范措施

校园网是教师和学生学习、交流的重要平台。随着网络服务项目的巨增,网络安全的问题也显得尤为突出。本文以广东某职业技术学院的校园网为硬件环境,分析了网络中存在的安全问题及如何防范,为建设安全、稳定、高效的校园网具有很大的参考作用。     

Evaluation of artery visualizations for heart disease diagnosis

Heart disease is the number one killer in the United States, and finding indicators of the disease at an early stage is critical for treatment and prevention. In this paper we evaluate visualization techniques that enable the diagnosis of coronary artery disease. A key physical quantity of medical interest is endothelial shear stress (ESS). Low ESS has been associated with sites of lesion formation and rapid progression of disease in the coronary arteries. Having effective visualizations of a patient's ESS data is vital for the quick and thorough non-invasive evaluation by a cardiologist. We present a task taxonomy for hemodynamics based on a formative user study with domain experts. Based on the results of this study we developed HemoVis, an interactive visualization application for heart disease diagnosis that uses a novel 2D tree diagram representation of coronary artery trees. We present the results of a formal quantitative user study with domain experts that evaluates the effect of 2D versus 3D artery representations and of color maps on identifying regions of low ESS. We show statistically significant results demonstrating that our 2D visualizations are more accurate and efficient than 3D representations, and that a perceptually appropriate color map leads to fewer diagnostic mistakes than a rainbow color map.     

混合模糊PID控制器在伺服控制系统中的应用

在分析了直流无刷电机伺服控制系统的基础上,提出了一种混合模糊PID跟踪控制器模型.该模糊PID控制器由3个并行的次模糊控制器组成,应用模糊算法在线自动整定PID参数;并利用Matlab/simulink建立仿真模型对模糊推理控制算法进行验证.仿真结果表明,混合模糊PID控制器的动静态特性优于传统单一的PID控制,对设计性能优良的伺服控制系统具有借鉴意义.     

一种基于UML的实时工作流建模方法研究

实时系统由于其业务对时间要求的特殊性,使得传统工作流技术难以满足其需求.在传统工作流的基础上,针对实时系统提出了实时工作流的概念,并建立了实时工作流元模型.与传统的工作流相比,主要对工作流的时间约束和异常处理进行了考虑.在活动上扩展了启动时间和执行时间,在工作流过程上扩展了执行时间,在并发活动上扩展了并发时间约束等,此外,元模型中还考虑了活动的超时异常以及应用程序和活动之间的执行关系.为了能够利用实时工作流元模型进行实时工作流建模,通过扩展UML定义了一种实时工作流描述语言,并分别从设计要求、定义技术和profile三个方面对实时工作流描述语言进行了阐述,给出了实时工作流的建模规则.最后结合船舶指控系统的具体实例,对建模方法进行了说明.     

一种自反馈细胞神经网络稳定性分析及在函数优化中的应用

提出一种具有暂态混沌的细胞神经网络,该网络是利用欧拉算法将模型的状态方程转化为离散形式并引入一项负的自反馈而形成的.由对单个神经元的仿真发现,该模型具有分叉和混沌的特性.在函数优化中,该网络首先经过一个倍周期倒分叉过程进行混沌搜索;然后进行类似Hopfield网络的梯度搜索.由于该网络利用了混沌搜索固有的随机性和轨道遍历性,因而具有较强的全局寻优的能力.最后通过2个函数优化的例子验证了该网络的有效性.