Fundamental properties of reset control systems

Reset controllers are linear controllers that reset some of their states to zero when their input is zero. We are interested in their feedback connection with linear plants, and in this paper we establish fundamental closed-loop properties including stability and asymptotic tracking. This paper considers more general reset structures than previously considered, allowing for higher-order controllers and partial-state resetting. It gives a testable necessary and sufficient condition for quadratic stability and links it to both uniform bounded-input bounded-state stability and steady-state performance. Unlike previous related research, which includes the study of impulsive differential equations, our stability results require no assumptions on the evolution of reset times.     

Computer support for strategic organizational decision-making

While information systems continue to be promoted within organizations as tools to support strategic decision-making, there is growing concern over the ability of such systems to model the social and political complexity of the situations to which they are being applied. This paper examines the nature of organizational decision-making and the use of computer-based systems to support this activity. The debate queries the extent to which such artifacts should be allowed to become enmeshed and embedded within the strategic decision-making activities of organizations which operate within increasingly complex environments.     

Gorillas (Gorilla gorilla) and Orangutans (Pongo pygmaeus) Encode Relevant Problem Features in a Tool-Using Task.

Two important elements in problem solving are the abilities to encode relevant task features and to combine multiple actions to achieve the goal. The authors investigated these 2 elements in a task in which gorillas (Gorilla gorilla) and orangutans (Pongo pygmaeus) had to use a tool to retrieve an out-of-reach reward. Subjects were able to select tools of an appropriate length to reach the reward even when the position of the reward and tools were not simultaneously visible. When presented with tools that were too short to retrieve the reward, subjects were more likely to refuse to use them than when tools were the appropriate length. Subjects were proficient at using tools in sequence to retrieve the reward. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Strategic Control of Multiple Routes in Imitation of Actions.

The aim of this study was to bring to the surface the strategic use of imitative processes in the context of a 2-route model: (a) direct imitation, used in reproducing new, meaningless actions, and (b) imitation based on stored semantic knowledge of familiar meaningful actions. Three experiments were carried out with healthy participants who reproduced meaningful and meaningless actions within an established time limit. The study investigated 3 factors that could potentially affect the selection of processes used for imitation: (a) the composition of the experimental list (blocked or mixed presentation), (b) the presence-absence of instructions (Experiments 1 and 2), and (c) the relative proportions of the stimuli (Experiment 3). Overall, the results suggest that each of these factors influences the selection of imitative strategies in healthy individuals with temporarily reduced capacities, as happens in the case of brain-damaged patients. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Memory organization of action events and its relationship to memory performance.

Previous research yielded inconsistent results regarding the memory organization of self-performed actions. The authors propose that task performance changes the very basis of memory organization. Enactment during study and test (Experiment 1) yielded stronger enactive clustering (based on motor-movement similarities), whereas verbal encoding yielded stronger conceptual clustering (based on semantic-episodic similarities). Enactment enhanced memory quantity and memory accuracy. Both measures increased with enactive clustering under self-performance instructions but with conceptual clustering under verbal instructions. Enactment only during study (Experiment 2) or only during testing (Experiment 3) also enhanced enactive clustering. It is proposed that different conditions affect the relative salience of different types of memory organization and their relative contribution to recall. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

贝氏体钢内水冷穿孔顶头的粘钢及防止措施

从顶头生产工艺控制的角度,分析了贝氏体钢内水冷穿孔顶头产生粘钢的原因、特点和机制,指出掉鼻、缺肉是顶头粘钢的另一种更为严重的失效形式,强化熔炼工艺控制和保证夹杂物总量在A0.5B1C0.5D1级水平,粘钢问题可以得到有效控制。     

A New Approach to Abstract Syntax with Variable Binding

The permutation model of set theory with atoms (FM-sets), devised by Fraenkel and Mostowski in the 1930s, supports notions of ‘name-abstraction’ and ‘fresh name’ that provide a new way to represent, compute with, and reason about the syntax of formal systems involving variable-binding operations. Inductively defined FM-sets involving the name-abstraction set former (together with Cartesian product and disjoint union) can correctly encode syntax modulo renaming of bound variables. In this way, the standard theory of algebraic data types can be extended to encompass signatures involving binding operators. In particular, there is an associated notion of structural recursion for defining syntax-manipulating functions (such as capture avoiding substitution, set of free variables, etc.) and a notion of proof by structural induction, both of which remain pleasingly close to informal practice in computer science. Received October 2000 / Accepted in revised form April 2001     

灭多威及其混合剂对棉铃虫的杀卵作用和生化机理

用灭多威及其混合剂处理不同发育阶段的棉铃虫卵和初孵幼虫，生化法测定不同发育阶段卵中的乙酰胆碱酯酶，羧酸酯酶活性和蛋白质含量。结果表明，灭多威及其混合剂对初产卵杀卵作用较小，对发育至１日龄以后卵的杀卵作用大；３种混合剂对初孵幼虫的击倒毒力均高于灭多威；该类药剂杀卵作用大小与卵内乙酰胆碱酯酶的活性呈正相关。     

改善钢桥面铺装层高温作用的有效措施

为了降低钢桥面铺装层内较高的温度,提高铺装材料使用性能,推迟桥面的早期破坏.采用有限元手段,以傅里叶传热定律为理论基础,根据气象部门提供的气象资料,对开放式钢箱梁及封闭式钢箱梁铺装层的温度场进行研究.结果表明:开放式箱梁可以降低桥面铺装层温度,降低高温持续作用时间,改变桥面铺装层高温的作用位置.     

基于Pylinac的放射治疗QA数字化分析系统

目的: 建立放射治疗直线加速器质量保证(Quality Assurance, QA)标准化体系和数字化分析系统是提升放疗水平和质量的有效途径. 方法: 基于Pylinac函数库, 采用Django框架和MySQL数据库结构搭建QA数字化分析系统, 并通过临床测试来评价该系统的稳定性与实用性. 结果: 放射治疗QA数字化分析系统不仅有利于监控及回顾分析直线加速器的运行状况, 而且有效减少医用直线加速器QA流程中计算分析的时间, 同时该系统还有助于放疗科新入职物理师快速熟悉QA流程. 结论: QA数字化分析系统在简化QA工作流程, 提高工作效率的同时, 更对放射治疗直线加速器的治疗体系中QA标准化起到进一步推进作用.