钉子与篱笆

We should learn how to control ourselves and look before you leap.生活中我们要学会控制自己并且三思而后行。     

成功演讲的10条秘诀

Feeling some nervousness before giving a speech is natural and healthy. It shows you care about doing well. But, too much nervousness can be detrimental. Here's how you can control your nervousness and make effective, memorable presentations: 演讲之前感到些许紧张是自然、有益的。这表明你渴望把事情做好。不过,过度紧张则会适得其反。这里教给你一些如何控制紧张情绪,进而使演讲达到预期效果、令入难忘的方法:     

美国年轻人常用的口头禅

1.I t's cool.cool是青少年(teen-agers)常用的字,其真正意思是指something good or acceptable可以接受的好事;situation is under control可以控制的情况     

超冗余度机械手自律分散控制算法

介绍了一种超冗余度机械手的控制算法,它采用自律分散控制方法来指导冗余度机械手末端执行器的运动,实现做功最小,从而避免采用需复杂计算的求逆解的方法,大大简化了机械手的算法和控制,具有高度的鲁棒性和容错性.,The control method of highly redundant robot manipulators is introduced. A decentralized autonomous control scheme is used to guide the movement of robot manipulators so that the work done by manipulators is minimized. The method of computing pseudoinverse which needs too many complicated calculation can be avoided. Then the calculation and control of robots are simplified. At the same time system robustness/fault tolerance is achieved.     

悬臂板的主动控制及稳定性分析

研究悬臂板的主动控制及稳定性,以闭环控制系统方程的特征值分析为基础,分析研究了其稳定性.研究表明主动控制在增加系统阻尼性能的同时,亦可能导致系统出现不稳定现象.文中指出当仅有对点之间的负反馈时,系统是渐近稳定的;当负反馈增益矩阵呈非对称或对称但非正定时,系统可能会出现非稳定.,Active vibration control and stability analysis of cantilever plate are discussed. Based on the analysis of characteristic equation of the closed-loop control system, it is shown that such an active control may increase damping properties of the system, meanwhile it may result in instability of the system. It is stable when the feedback only occurs between the collocated sensors and actuators, but it may be unstable when there exists the feedback between sensors and actuators, which mainly depends on the property of the gain matrix of feedback. If the gain matrix is symmetric and definitely positive, the system is stable.     

营销,因互联网而改变

One prediction shows that 55 percent of advertising by volume will be carried on the Internet by 2005. Consumers will have control and choice of deciding what products to buy, and where to buy them: they will also have control over what advertisements they watch, and     

一种减小无刷直流电机转矩脉动的广角波控制方法

In order to deal with torque pulsation problem caused by traditional control method for brushless DC （BLDC） motor and to achieve high precision and good stability, a novel control strategy is proposed. Compared with the traditional control scheme, by using phase voltage as a control objective and making waveform of phase current approximately quasi-sinusoidal, torque ripple of BLDC motor is reduced from the original 14% to 3.4%, while toque is increased by 3.8%. Furthermore, by detecting zero-crossings of back electromotive force （BEMF） with non-conducting phases, sensorless control is realized. The new control strategy is simple. It can minimize torque ripple, increase torque, and realize sensorless control for BLDC motor. Simulation and experiments show good performance of BLDC motor by using the new control method.     

Optimization of time-delayed feedback control of seismically excited building structures

An optimization method for time-delayed feedback control of partially observable linear building structures subjected to seismic excitation is proposed. A time-delayed control problem of partially observable linear building structure under horizontal ground acceleration excitation is formulated and converted into that of completely observable linear structure by using separation principle. The time-delayed control forces are approximately expressed in terms of control forces without time delay. The control system is then governed by Itoe stochastic differential equations for the conditional means of system states and then transformed into those for the conditional means of modal energies by using the stochastic averaging method for quasi-Hamiltonian systems. The control law is assumed to be modal velocity feedback control with time delay and the unknown control gains are determined by the modal performance indices. A three-storey building structure is taken as example to illustrate the proposal method and the numerical results are confirmed by using Monte Carlo simulation.     

中学生控制源与人际关系发展的研究

“控制源理论”是由罗特(J.B.Rotter)对心理控制源进行研究并发展起来的归因理论,它与海德、韦纳等的归因理论不同,控制源理论认为知觉者之间存在着一些稳定的个体的差异,这些个体差异影响了因果推论。因此,控制源理论既是一个归因理论,也是一个个性理论。内外控是衡量这种个体差异的维度,内控者(internal control)倾向把自己的行为看成是引发随后事件的主要因素,认为自己的成败祸福取决于自身因素;而外控者(external control)则常把行为之后的事件看成是机遇、运气或超出自己能力的外部力量所决定的,从而不愿去做一些必要的努力和尝试控…     

质子交换膜燃料电池系统电气输出的动态控制

This paper discusses dynamic characteristics of proton exchange membrane fuel cell (PEMFC) under rapid fluctuation of power demand. Wavelet neural network is adopted in the identification of the characteristic curve to predict the voltage. The system control scheme of the voltage and power is introduced. The corresponding schemes for voltage and power control are studied. MATLAB is used to simulate the control system. The results reveal that the adopted control schemes can produce expected effects. Corresponding anti-disturbance and robustness simulation are also carried out. The simulation results show that the implemented control schemes have better robustness and adaptability.     

时滞系统模糊积分控制研究

针对时滞系统非线性、滞后性等特点,运用模糊积分控制算法对系统进行控制.通过Matlab的Simulink工具箱建立模型,并做了模糊积分控制、传统模糊控制(Fuzzy control)仿真对比试验.仿真结果表明,模糊积分控制在调节时间、稳态性能等指标上明显优于模糊控制,具有更好的快速性和自适应性,是时滞系统较为理想有效的控制方法.     

Cost control for real estate development projects in China - Part 1: Literature review

The background and purpose, and the current situation of the cost control theory of real estate development project are disscussed in the paper. Problems of cost control for real estate development projects in China are analyzed and summarized. According to the real estate development project cost control problems and related factors, a cost control index system of real estate development enterprise, and a cost control factors index system of real estate projects are constructed respectively. Cost control in the five stages of a real estate development project is introduced and summarized respectively. The five stages include： the investment decision-making, planning and design stage, the bidding phase, project implementation stage, and rental or sale.     

Quality incentive based congestion control for multimedia communication over IP networks

In this paper we introduce a framework for using quality as an incentive to promote proper application level congestion control. Through integrating a joint-source channel coder and feedback-based congestion control scheme, we are able to construct accurate and efficient quality incentives. The framework is applicable in all network architectures where end-to-end congestion control may be used, and is as such not specific to either best-effort or traffic class-based architectures. The concept is presented along with preliminary simulations that highlight the resulting rate control accuracy. We also discuss how to implement some well-known congestion control schemes within our framework.     

Review on development progress of automatic manual transmissions control

In recent years, the sustainable development of automatic manual transmissions (AMTs) control in vehicles is conspicuous. The control applications have grown fast and steadily due to the tremendous progress in power electronics components and the control software that enhance the requirements for delivering higher vehicles performance. AMTs control strategies achieve a reduction in the driveline dynamic oscillations behavior during gear shifting and clutch starting up processes. AMTs future expectations are an increase of torque capacity, more speed ratios and the development of advanced and efficient electronic control systems. This paper concerns with the progressing view of AMTs in the past, today and future, gives an overview of the potential dynamic problems concerned with AMTs and some control strategies used to solve those problems.     

Nonlinear stochastic optimal bounded control of hysteretic systems with actuator saturation

A modified nonlinear stochastic optimal bounded control strategy for random excited hysteretic systems with actuator saturation is proposed. First, a controlled hysteretic system is converted into an equivalent nonlinear nonhysteretic stochastic system. Then, the partially averaged Itoe stochastic differential equation and dynamical programming equation are established, respectively, by using the stochastic averaging method for quasi non-integrable Hamiltonian systems and stochastic dynamical programming principle, from which the optimal control law consisting of optimal unbounded control and bang-bang control is derived. Finally, the response of optimally controlled system is predicted by solving the Fokker-Planck-Kolmogorov （FPK） equation associated with the fully averaged Itoe equation. Numerical results show that the proposed control strategy has high control effectiveness and efficiency.     

On modal energy in civil structural control

A new control strategy based on modal energy criterion is proposed to demonstrate the effectiveness of the control system in reducing structural earthquake responses. The modal control algorithm combining LQR （linear quadratic regulator） control algorithm is adopted in the discrete time-history analysis. The various modal energy forms are derived by definition of the generalized absolute displacement vector. A preliminary numerical study of the effectiveness of this control strategy is carried out on a 20-storey framed steel structural model. The controlled performance of the model is studied from the perspectives of both response and modal energy. Results show that the modal energy-based control strategy is very effective in reducing structural responses as well as in consuming a large amount of modal energy, while augmentation of additional generalized control force corresponding to the modes that contain little modal energy is unnecessary, as it does little help to improve the controlled structural performance.     

Management Control Systems and Innovation

It’s widely argued that a business environment of budget control and innovation can be antithetical.This essay explores the ways that management accounting and control practices might enable organizations to achieve both control and innovation in the current globalised economy on a basis of the different views in the management control systems(MCSs) and innovation.     

Electric wheelchair control system using brain-computer interface based on alpha-wave blocking

A brain-computer interface （BCI） -based electric wheelchair control system was developed, which enables the users to move the wheelchair forward or backward, and turn left or right without any pre-learning. This control system makes use of the amplitude enhancement of alpha-wave blocking in electroencephalogram （EEG） when eyes close for more than 1 s to constitute a BCI for the switch control of wheelchair movements. The system was formed by BCI control panel, data acquisition, signal processing unit and interface control circuit. Eight volunteers participated in the wheelchair control experiments according to the preset routes. The experimental results show that the mean success control rate of all the subjects was 81.3%, with the highest reaching 93.7%. When one subject＇s triggering time was 2.8 s, i.e., the flashing time of each cycle light was 2.8 s, the average information transfer rate was 8.10 bit/min, with the highest reaching 12.54 bit/min.     

Dynamic velocity feed-forward compensation control with RBF-NN system identification for industrial robots

A dynamic velocity feed-forward compensation control (DVFCC) approach with RBF neural network (RBF-NN) dynamic model identification was presented for the adaptive trajectory tracking of industrial robots.The proposed control approach combined the advantages of traditional feedback closed-loop position control and computed torque control based on inverse dynamic model.The feed-forward compensator used a nominal robot dynamics as accurate dynamic model and on-line identification with RBF-NN as uncertain part to improve dynamic modeling accuracy.The proposed compensation was applied as velocity feed-forward by an inverse velocity controller that can convert torque signal into velocity in the standard industrial controller.Then,the need for a torque control interface was avoided in the real-time dynamic control of industrial robot.The simulations and experiments were carried out on a gas cutting manipulator.The results show that the proposed control approach can reduce steady-state error,suppress overshoot and enhance tracking accuracy and efficiency in joint space and Cartesian space,especially under highspeed condition.