基于时延库所Petri网的动态联盟任务调度研究

针对动态联盟中任务调度的特点,提出了采用时延库所Petri网对动态联盟任务调度进行建模。给出了模型的形式化描述及变迁规则,对动态联盟中的产品加工类型进行了分类,并建立了各种加工类型的时延库所Petri网模型,分析了通过模型中零时差的库所求解关键路径和利用可达图求解合理调度方案的方法。最后,以实例表明了该方法的可行性和有效性。     

任务驱动法在高校计算机基础的教学研究

随着社会和科技的不断发展,计算机的应用已经很普及,本文针对任务驱动法进行概述,分析了任务驱动法在高校计算机基础课程中的实践,提出了要明确教学目标、及时对学生进行指导、及时进行纠错,发现教学难点、及时进行归纳总结的实践方法。     

医联体中协同医疗任务分配问题

针对区域医疗联合体中协同医疗任务分配问题,将诊疗效果、医疗费用、医院环境和服务态度确定为衡量患者满意度的定性指标,并借助模糊数学中的隶属度理论将定性指标定量化。以患者满意度为目标函数,并在符合临床路径标准的时间、成本、质量约束下建立0-1整数规划模型。模型求解时,采用遗传算法求解,并设计了能直观反映研究问题的矩阵形式染色体编码,最后仿真数据验证了上述模型和算法的有效性。     

不确定信息下基于拍卖算法的多无人机同时到达攻击多目标

针对不确定信息下的多无人机同时到达攻击多目标的控制策略问题,将拍卖算法和区间一致性算法相结合,提出了不确定信息下的多无人机同时到达的控制方法。首先通过拍卖算法,给出了多无人机对多目标的任务分配方法;然后定义了区间一致性算法,提出了不确定信息下的多无人机同时到达的控制方法,实现了多无人机到达多目标的时间上趋于一致;最后进行仿真,验证了该方法的可行性和有效性。     

Combined continuum damage‐embedded discontinuity model for explicit dynamic fracture analyses of quasi‐brittle materials

In this paper, a novel constitutive model combining continuum damage with embedded discontinuity is developed for explicit dynamic analyses of quasi‐brittle failure phenomena. The model is capable of describing the rate‐dependent behavior in dynamics and the three phases in failure of quasi‐brittle materials. The first phase is always linear elastic, followed by the second phase corresponding to fracture‐process zone creation, represented with rate‐dependent continuum damage with isotropic hardening formulated by utilizing consistency approach. The third and final phase, involving nonlinear softening, is formulated by using an embedded displacement discontinuity model with constant displacement jumps both in normal and tangential directions. The proposed model is capable of describing the rate‐dependent ductile to brittle transition typical of cohesive materials (e.g., rocks and ice). The model is implemented in the finite element setting by using the CST elements. The displacement jump vector is solved for implicitly at the local (finite element) level along with a viscoplastic return mapping algorithm, whereas the global equations of motion are solved with explicit time‐stepping scheme. The model performance is illustrated by several numerical simulations, including both material point and structural tests. The final validation example concerns the dynamic Brazilian disc test on rock material under plane stress assumption. Copyright © 2014 John Wiley & Sons, Ltd.     

Choking under pressure: Multiple routes to skill failure.

Poor performance in pressure-filled situations, or “choking under pressure,” has largely been explained by two different classes of theories. Distraction theories propose that choking occurs because attention needed to perform the task at hand is coopted by task-irrelevant thoughts and worries. Explicit monitoring theories claim essentially the opposite—that pressure prompts individuals to attend closely to skill processes in a manner that disrupts execution. Although both mechanisms have been shown to occur in certain contexts, it is unclear when distraction and/or explicit monitoring will ultimately impact performance. The authors propose that aspects of the pressure situation itself can lead to distraction and/or explicit monitoring, differentially harming skills that rely more or less on working memory and attentional control. In Experiments 1–2, it is shown that pressure that induces distraction (involving performance-contingent outcomes) hurts rule-based category learning heavily dependent on attentional control. In contrast, pressure that induces explicit monitoring of performance (monitoring by others) hurts information-integration category learning thought to run best without heavy demands on working memory and attentional control. In Experiment 3, the authors leverage knowledge about how specific types of pressure impact performance to design interventions to eliminate choking. Finally, in Experiment 4, the selective effects of monitoring-pressure are replicated in a different procedural-based task: the serial reaction time task. Skill failure (and success) depends in part on how the performance environment influences attention and the extent to which skill execution depends on explicit attentional control. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Task-switching performance with 1:1 and 2:1 cue–task mappings: Not so different after all.

When task-switching studies use the task-cuing procedure with a 1:1 cue–task mapping, task switching and cue switching are confounded, which is problematic for interpreting switch costs. The use of a 2:1 cue–task mapping is a potential solution to this problem, but it is possible that introducing more cues may also introduce marked changes in task-switching performance. In 5 experiments involving 160 subjects, the authors compared performance with 1:1 and 2:1 mappings across several methodological changes. Differences in switch costs between mappings were small and, in most analyses, nonsignificant. In all experiments, both mappings yielded significant reductions in switch cost across cue–target interval, and there were significant cue-switching effects with the 2:1 mapping. A model of cue encoding fit the data from both mappings about equally well. Overall, task-switching performance was more similar than it was different between mappings, leading the authors to suggest that the use of a 2:1 mapping is a viable solution to the problem associated with a 1:1 mapping. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The relations of daily task accomplishment satisfaction with changes in affect: A multilevel study in nurses.

Focusing on a sample of nurses, this investigation examined the relationships of daily task accomplishment satisfaction (for direct and indirect care tasks) with changes in positive and negative affect from preshift to postshift. Not accomplishing tasks to one's satisfaction was conceptualized as a daily workplace stressor that should increase daily negative affect and decrease daily positive affect from preshift to postshift. Further, because of the greater centrality of direct care nursing tasks to nursing work role identities (relative to indirect care tasks), we expected that task accomplishment satisfaction (or lack thereof) for these tasks would have stronger effects on changes in affect than would task accomplishment satisfaction for indirect care tasks. We also examined 2 person-level resources, collegial nurse–physician relations and psychological resilience, as moderators of the relationships among these daily variables, with the expectation that these resources would buffer the harmful effects of low task accomplishment satisfaction on nurse affect. Results supported almost all of the proposed effects, though the cross-level interactions were observed only for the effects of indirect care task accomplishment satisfaction on affect and not for direct care task accomplishment satisfaction on affect. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

故障装备检测任务分解模型评估

为解决故障装备检测过程存在的突出问题,提高检测任务的执行效率,降低任务执行过程中的复杂程度,在掌握一般检测任务执行过程的基础上,总结了现有故障装备检测过程中常见任务的不同类型;以检测过程中相互间具有约束关系的任务分解为研究对象,借鉴任务关联矩阵(TAM)等相关概念,提出了基于检测任务分解的评估方法和过程模型,从检测周期和资源占用2个角度实现了对检测任务分解程度的定性分析,对任务内聚性、耦合性以及均衡性的定量计算,最后通过实例验证了该方法和模型的可行性,为评估不同检测任务分解方案提供了参考。