Preschool executive control on the Shape School task: Measurement considerations and utility.

Executive functions (EF) necessary for purposeful goal-directed activities undergo rapid change and development during the preschool years. However, of the few psychometrically valid measures of EF suitable for use with preschoolers, information on task sensitivity and predictive validity is scant. The neurodevelopmental correlates of early executive difficulties are also largely unknown. In this study, the discriminant and predictive validity of the recently developed Shape School task (Espy, Bull, Martin, & Stroup, 2006) was examined with data from a regional sample of 209 preschool children at age 4 years. A 2-tiered measurement approach was used, with task completion examined in addition to efficiency. Children's performance was also examined in relation to functioning in a range of neurodevelopmental domains. The Shape School task showed some usefulness in capturing expected differences between at-risk and typically developing children. Performance loaded heavily on language and global cognitive abilities. However, several other factors were also implicated, including attention, motor skills, and ocular control. In addition, task completion and efficiency scores appeared to reflect different aspects of performance, and their associations with neurodevelopmental function and later academic achievement on the Woodcock-Johnson Tests of Achievement at age 6 years also differed. Implications for the application of the Shape School task are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Studies on the heating capacity control of a multi-type heat pump system applying a multi-input multi-output (MIMO) method

This paper describes a method to control capacity of a multi-type heat pump system. Because indoor units are interconnected, alteration of the heating or cooling setting of one indoor unit can influence the performance of the other indoor units. Proportional-integral (PI) controllers were used to assess system performance, and the PI controllers’ gain values were optimized by using a genetic algorithm. A system model was established following a system identification optimization process, and a pseudo random binary sequence was selected as the system identification input signal. A multi-input multi-output (MIMO) controller was more effective in reducing such cross-coupling effects than a single-input single-output (SISO) controller. The temperature at the secondary fluid outlet in the condenser and the saturation pressure at the evaporator were selected as the control variables in the MIMO controller. The experimental results showed that an optimized MIMO controller could reduce overshoot by up to 40% compared with the results using a SISO controller.     

Optimality and convergence of adaptive optimal control by reinforcement synthesis

Adaptive Optimal Control (AOC) by reinforcement synthesis is proposed to facilitate the application of optimal control theory in feedback controls. Reinforcement synthesis uses the critic–actor architecture of reinforcement learning to carry out sequential optimization. Optimality conditions for AOC are formulated using the discrete minimum principle. A proof of the convergence conditions for the reinforcement synthesis algorithm is presented. As the final time extends to infinity, the reinforcement synthesis algorithm is equivalent to the Dual Heuristic dynamic Programming (DHP) algorithm, a version of approximate dynamic programming. Thus, formulating DHP with the AOC approach has rigorous proofs of optimality and convergence. The efficacy of AOC by reinforcement synthesis is demonstrated by solving a linear quadratic regulator problem.     

31.5mn车轮预成型油压机自动控制系统研究

介绍了31.5 MN车轮预成型油压机流程及参数,阐述了控制系统S7-300的结构配置及其完成主要功能。     

Driver sensitivity to brake pulse duration and magnitude

Adaptive cruise control (ACC) requires that the driver intervene in situations that exceed the capability of ACC. A brake pulse might provide a particularly compatible means of alerting the driver to situations in which the acceleration authority of the ACC has been exceeded. This study examined the sensitivity of the driver to brake pulses of five different amplitudes (0.01–0.025 g) and five different durations (50–800 ms). Drivers were sensitive to accelerations as low as 0.015 g. Pulse duration interacted with pulse amplitude, such that moderate duration pulses were more detectable than long and short duration pulses at intermediate levels of pulse amplitude. A power function with an exponent of 1.0 accounted for 99% of the variance in drivers' sensitivity to pulse amplitude; however, a power function with an exponent of 0.23 accounted for only 70% of the variance in drivers' sensitivity to pulse duration. These results can help designers create ACC algorithms and develop brake pulse warnings.     

Fault management in process control: eye movements and action

Operators controlled a simulated thermal hydraulic system based on Crossman's waterbath task. They were required to keep the system at set points for temperature, level and flow rates. The system was subjected to disturbances and to failures, which the operators were required to manage. Behavioural data were collected in the form of keystroke commands, and in addition eye movements were measured. Evidence for ‘cognitive lockup’ and for a preference for serial fault management were found. Fixation durations do not change, but faulty subsystems are examined more frequently. During lockup other subsystems may be examined but action on them is delayed. Eye movements give considerable additional insight into the nature of process control information processing compared with traditional measures of operator performance.     

悬挂式接管焊接机器人机电系统

针对接管相贯线处的焊接特点,研发了悬挂式接管焊接机器人,介绍了机械结构特点和适用性.控制系统采用工业PC作为主控计算机和PMAC多轴控制卡进行多轴控制,利用二级控制结构实现作业管理,协调各轴运动完成焊接作业.进行了在筒体上外接管和内接管的焊接试验与在椭球体上外接管与内接管的焊接试验.结果表明,机器人的机械本体结构和控制系统能够实现多种接管的焊接需求,能够很好地完成接管相贯线处的焊接,提高了工作效率和焊接质量.     

防控甲流期间做好团学活动的思考

本文在分析了防控甲流工作的重要性以及团学活动的重要意义的前提下,初步探讨了在防控甲流期间做好团学活动的具体措施。     

大体积砼裂缝成因及控制技术措施

针对大体积砼温度裂缝问题,首先分析了大体积砼温度裂缝产生的原因,并提出了相应的控制技术措施。