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991.
To investigate whether the functioning of cognitive control is contingent upon the attentional set in attentional blink (AB), which is a deficit in reporting the second (T2) of two targets when it occurs 200—500 ms after the first (T1) in a rapid serial visual presentation (RSVP) stream, this study examined the pattern of cuing effects in which two kinds of colored cues match (i.e., in the same attentional set) or mismatch (i.e., in a different attentional set) the color of the upcoming T2. Participants of the study were asked to monitor T1 and T2 in triple RSVP streams while the cue-T2 onset synchrony (CTOA) varied from 90 ms to 270 ms and the cue and T2 might or might not occur in the same RSVP stream as T1. Relative to the uncued condition, both the same-color and the different-color cues produced cuing effects, but the effect was larger and lasted for a longer time for the former than for the latter, whether the cue (and T2) and T1 occurred in the same stream or not. Cues with short CTOA in general enhanced T2 performance more greatly during the AB period than outside of the AB period, suggesting that cues with short CTOA could open the attentional window in advance of T2 and thus facilitate the T2 processing. These findings are consistent with the theory that the salient stimulus captures attention and opens the attentional window irrespective of the attentional set defined for the target; but the attention capture effect of the cue can be quickly overridden by the top-down control when the cue does not match the attention set. Thus both the top-down attentional control setting and the bottom-up attentional capture process function during attentional blink. 相似文献
992.
提出一种IC芯片设计中双极型器件直流模型参数的提取方法。采取GP模型建立双向目标函数进行全局优化提取,分1级和2级参数两层处理.1级参数系提取IC设计中各管的共同参数,2级参烽则为提取与各个管的结构和尺寸相关的特定参数,尽管提取对象只是样管,但可以由模型内在关系通过程序计算出各管的特定参数,从而保证了电路模拟所需输入参数的真实性。 相似文献
993.
The distribution function of the hyperbranched polymers formed from the self-condensing vinyl polymerization with unequal reactivities was derived and the differential equations for the second moments are established, based on the variable of the conversion of B^* groups. The various average degrees of branching can be designed by suitable values of reactivities ratio (r) and the conversion of A group (x). In order to reach the maximum degree of branching at a specified x, r needed is dependant on the value of x. The higher the x, the less the r needed is for the maximum value of degree of branching. At the end of the reaction, the maximum degree of branching reaches 0.5 with r=2.59. 相似文献
994.
995.
996.
高素质的师资队伍是实施素质教育的关键 总被引:5,自引:0,他引:5
教师是素质教育直接的实施者,教师素质的高低,直接关系到素质教育的成败。全面提高教师素质,使广大教师适应素质教育发展的需要,是一项十分紧迫而艰辛的任务。 相似文献
997.
Probabilistic D-Clustering 总被引:1,自引:1,他引:0
We present a new iterative method for probabilistic clustering of data. Given clusters, their centers and the distances of
data points from these centers, the probability of cluster membership at any point is assumed inversely proportional to the
distance from (the center of) the cluster in question. This assumption is our working principle.
The method is a generalization, to several centers, of theWeiszfeld method for solving the Fermat–Weber location problem.
At each iteration, the distances (Euclidean, Mahalanobis, etc.) from the cluster centers are computed for all data points,
and the centers are updated as convex combinations of these points, with weights determined by the above principle. Computations
stop when the centers stop moving. 相似文献
998.
Number crunching vs. number theory: computers and FLT,from Kummer to SWAC (1850–1960), and beyond 总被引:1,自引:1,他引:0
Leo Corry 《Archive for History of Exact Sciences》2008,62(4):393-455
The present article discusses the computational tools (both conceptual and material) used in various attempts to deal with
individual cases of FLT, as well as the changing historical contexts in which these tools were developed and used, and affected
research. It also explores the changing conceptions about the role of computations within the overall disciplinary picture
of number theory, how they influenced research on the theorem, and the kinds of general insights thus achieved. After an overview
of Kummer’s contributions and its immediate influence, I present work that favored intensive computations of particular cases
of FLT as a legitimate, fruitful, and worth-pursuing number-theoretical endeavor, and that were part of a coherent and active,
but essentially low-profile tradition within nineteenth century number theory. This work was related to table making activity
that was encouraged by institutions and individuals whose motivations came mainly from applied mathematics, astronomy, and
engineering, and seldom from number theory proper. A main section of the article is devoted to the fruitful collaboration
between Harry S. Vandiver and Emma and Dick Lehmer. I show how their early work led to the hesitant introduction of electronic
computers for research related with FLT. Their joint work became a milestone for computer-assisted activity in number theory
at large. 相似文献
999.
工程造价管理贯穿于整个基本建设过程,并发生在不同单位,但设计单位是控制工程造价的关键,本文分四个方面论述了设计单位控制工程造价的途径。 相似文献
1000.
Thomas L. SAATY 《系统科学与系统工程学报(英文版)》2004,13(4):385-404
1. Introduction This is the fourth exposition on theAnalytic Hierarchy Process. It is true thatmany decisions we make subconsciously ariseout of our physical and biological needs andderive from the pressure to survive physically.We also make subconsciou… 相似文献