论国家教育考试突发事件的技术控制策略

国家教育考试是社会生活的重要组成部分。相关部门对国家教育考试突发事件的处置能力已经成为确保考试安全、保障社会安定的关键因素之一。本文从技术层面,探讨国家教育考试实施过程中对突发事件的预防与控制策略,以期通过对预警技术、信息技术、监控技术、应急技术和法律技术的策略应用,在考试组织实施过程中发挥积极的预防、控制和保障作用。     

论高考命题质量控制机制的建设

针对目前高考命题存在的不足,从正确把握命题的指导思想和原则,规范和完善考试大纲(说明),科学编制试题,合理设计试卷,加强试卷命制质量的分析与反馈,改革命题的管理等一系列命题环节入手,探讨建立命题质量的控制机制。     

建筑工程项目成本控制分析

建筑工程项目成本控制是项目成本管理的重要内容之一,它不同于传统意义上的成本控制.具有自身的特点.项目成本控制是一种经济控制,它是根据项目工程的特点,随着项目的进展,对生产成本收入与支出进行监控,发现偏差,及时纠正,以达到在预算成本范围内实现目标的过程.     

基于大连机车车辆有限公司内部的物流运作手段与管理的问题探讨

随着信息化的来临,在市场竞争愈发激烈的背景下,越来越多的企业认识到高效的物流管理是降低产品成本、提高服务水平、缩短交货时间的重要手段,并能最终加强企业的综合竞争能力.而企业内部物流是指从原材料输入生产系统,经过储存、搬运、装卸、加工、装配等一系列物理与化学的转换直至输出生产系统的全部运动过程.该过程中各个环节相互配合、...     

美国科学家发现线虫线粒体代谢状态是控制生命长度的关键

据2010年12月4日好参考消息》援引美国每日科学网站2010年12月2日报道,美国得克萨斯大学卫生科学中心圣安东尼奥校区的杰弗里·巴特勒和沙恩·雷在《美国实验生物学联合会会志》月刊封面上发表了他们的这一研究结果。     

想象过滤与建构控制——萨义德《东方学》的教育想象

人是多面性和复杂化的异样存在。不同的地缘性存在、文化性存在和价值性存在及其不同群体在社会政治经济文化资本权力上的不同,使得双方的交往互动表现出建构或被建构、殖民或被殖民、主导或被主导的权力话语或文化霸权特征,教育亦如是。在既有的教育生活世界中,我国教育领域教师与学生、学校与教师和政府与学校三重基本关系之间也存在着想象与控制。可以以师生关系为范例阐明两相关系的基本样态、合理抉择及其和谐关系构建下的可能路径。     

WPT-based modal control on distributed structures with MRF-04K damper

The magnetorheological (MR) fluid damper-based semiactive control systems have received considerable attention for protecting structures against natural hazards such as strong earthquakes and high winds. In this paper, a novel modal controller using wavelet packet transform (WPT) is proposed for the vibration control of distributed structures. In the proposed control system, the WPT method is utilized to decompose the acceleration measurement and select the modes containing most of the WPT energy component as the dominant modes. Then, a modal controller is designed to control the dominant modes and the optimal active control force is solved. Finally, Clipped-optimal con- trol law is adopted to determine the voltage applied to each MR damper. A Kalman-filter observer, which estimates the full controlled modal states from local accelerometer feedbacks, is designed for rendering the controller to be more applicable to distributed structures with a large number of degrees of freedom. A numerical example of a stadium roof structure installed with MRF-04K damper is presented. The effectiveness of the controller is evaluated under both Tianjin and El Centro earthquake excitations. The superior performance and adaptability of the controller for versatile loading conditions are demonstrated through the comparison with traditional truncated modal controller.     

Development of integrated precision vibration-assisted micro-engraving system

A novel precision vibration-assisted micro-engraving system was developed by the integration of fast tool servo and ultrasonic elliptical vibration system, in which the flexure hinge was designed to avoid backlash and PID control algorithm was established to guarantee specific precision. Apart from experimental validation of the performance of the system, various micro-V-grooves cutting experiments on aluminum alloy, ferrous material and hard cutting material were performed, in which Kistler force sensor was used to measure cutting force. Through experiments, it was clear that the vibration-assisted micro-engraving system can ensure good quality of micro-V-grooves and reduce cutting force by about 60% compared with traditional removal process without ultrasonic vibration.     

Stabilization of Delayed Networks with Different Nodes

In this paper,the control of complex delayed networks with different nodes is proposed.Firstly,the stabilization of coupled networks with time delay is investigated.By constructing a Lyapunov function,a linear feedback controller design procedure for the networks is converted to the problem of solving a set of linear matrix inequalities.Then the results are extended to networks with both delayed dynamical nodes and delayed couplings.It is shown that the stabilization of complex networks is determined by the dynamics of each uncoupled node,coupling matrix and feedback gain matrix of networks.Two examples are simulated.In the first example,a network with 10 nodes consisting of Lorenz systems and systems proposed by Zhang in 2009 is given.It is found that the network states are divergent without control,and convergent under designed linear feedback controllers.In the second example,a larger network with 100 nodes consisting of delayed Chen systems and delayed Lorenz systems is given.The proposed method is also effective for large scale networks.     

伺服技术在卷烟机烟支重量控制系统中的应用

目前主流卷接机组烟支重量控制系统的执行部分均采用110V普通单相电机,存在着重量控制精度偏低、维修费用较高的问题．通过技术创新和改造,在ZJ15XG型机组上构建了由伺服系统、微型PLC组成的控制系统,有效地解决了原系统存在的问题,一台机组每年可节约费用近5万元．