Visual search for a conjunction of movement and form is parallel

Treisman has proposed when a human subject performs a visual search, the search is parallel for targets defined by a single feature, and serial for targets defined by a conjunction of features. Here we report that this is not true for targets defined by a conjunction of the features movement and form. Detection of a moving X among randomly distributed moving Os and static Xs is parallel. Search is uninfluenced by the stationary stimuli despite their spatial intermingling with the moving items. Thus, attention can be restricted to a spatially dispersed perceptual group, defined by common movement. This contradicts previous conclusions from visual search experiments that attention can only be assigned to contiguous regions of visual space. The search process first segregates the array into moving and stationary items, and then examines the moving group for the target form. Cells in the middle temporal region (cortical area MT) have the properties required to perform these operations.     

Interaction between colour and motion in human vision

There is a wealth of anatomical and psychological evidence which suggests that when people look at an object in the visual world, its various attributes such as colour, 'form', motion and depth are analysed by separate channels in the visual system. If so, how are these attributes put back together again to create a unified picture of the object? And if the object moves rapidly, how is perfect perceptual synchrony maintained between different features on its surface, if it is indeed true that they are being processed separately? Our evidence suggests that the visual system extracts certain conspicuous image features based on luminance contrast, and that the signals derived from these are then attributed to other features on the object, a process that we call 'capture'. Specifically, we find that when either illusory contours or random-dot patterns are moved in the vicinity of a colour-border, the colour border will also seem to move in the same direction even though it is physically stationary.     

概率模糊认知图

模糊认知图模型通过在传统认知图模型中引入模糊测度来量化概念间因果关系的影响程度。在继承模糊认知图模型优点的前提下，首次在概念间的因果关系中引入条件概率测度，提出概率模糊认知图模型。该模型不仅能表示概念间的定性及模糊因果关系，而且能表示概念间的条件概率因果关系，并能退化为模糊认知图。通过对复杂机械部件的拆卸与装配实验，具体阐述概率模糊认知图的应用。实验结果表明概率模糊认知图模型比较模糊认知图模型具有对现实世界更强的模拟能力。     

Change in pattern of ongoing cortical activity with auditory category learning

Humans are able to classify novel items correctly by category; some other animals have also been shown to do this. During category learning, humans group perceptual stimuli by abstracting qualities from similarity relationships of their physical properties. Forming categories is fundamental to cognition and can be independent of a 'memory store' of information about the items or a prototype. The neurophysiological mechanisms underlying the formation of categories are unknown. Using an animal model of category learning, in which frequency-modulated tones are distinguished into the categories of 'rising' and 'falling' modulation, we demonstrate here that the sorting of stimuli into these categories emerges as a sudden change in an animal's learning strategy. Electro-corticographical recording from the auditory cortex shows that the transition is accompanied by a change in the dynamics of cortical stimulus representation. We suggest that this dynamic change represents a mechanism underlying the recognition of the abstract quality (or qualities) that defines the categories.     

Individual differences in non-verbal number acuity correlate with maths achievement

Human mathematical competence emerges from two representational systems. Competence in some domains of mathematics, such as calculus, relies on symbolic representations that are unique to humans who have undergone explicit teaching. More basic numerical intuitions are supported by an evolutionarily ancient approximate number system that is shared by adults, infants and non-human animals-these groups can all represent the approximate number of items in visual or auditory arrays without verbally counting, and use this capacity to guide everyday behaviour such as foraging. Despite the widespread nature of the approximate number system both across species and across development, it is not known whether some individuals have a more precise non-verbal 'number sense' than others. Furthermore, the extent to which this system interfaces with the formal, symbolic maths abilities that humans acquire by explicit instruction remains unknown. Here we show that there are large individual differences in the non-verbal approximation abilities of 14-year-old children, and that these individual differences in the present correlate with children's past scores on standardized maths achievement tests, extending all the way back to kindergarten. Moreover, this correlation remains significant when controlling for individual differences in other cognitive and performance factors. Our results show that individual differences in achievement in school mathematics are related to individual differences in the acuity of an evolutionarily ancient, unlearned approximate number sense. Further research will determine whether early differences in number sense acuity affect later maths learning, whether maths education enhances number sense acuity, and the extent to which tertiary factors can affect both.     

Temporal hyperacuity in the electric sense of fish

It has recently become evident that sensory thresholds for certain tasks are lower than those expected from the properties of individual receptors. This perceptual capacity, termed hyperacuity, reveals the impressive information-processing abilities of the central nervous system. Although much is known about spatial hyperacuity, temporal hyperacuity has received little attention. Here we demonstrate that an electric fish, Eigenmannia, can detect modulations in the timing (phase) of an electrical signal at least as small as 400 ns. Such sensitivity exceeds the temporal resolution of individual phase-coding afferents. This hyperacuity results from a nonlinear convergence of parallel afferent inputs to the central nervous system; subthreshold inputs from particular areas of the body surface accumulate to permit the detection of these extremely small temporal modulations.     

基于模糊值概念网的模糊信息检索研究

在模糊值概念网中,任意两概念间的关联度可用模糊数的任意形式表示,概念间的关系可为模糊正相协或模糊负相协。为了减少模糊推理时间,模糊值概念网可看作是由关联矩阵和关系矩阵组成,关联矩阵中的元素代表概念问的关联度．关系矩阵中的元素代表概念间的关系。使用模糊正相协和模糊负相协可准确地表示用户的查询,增强了模糊信息检索系统的灵活性。将模糊值概念网的结构扩展到互联网,提出了一种基于网络型的模糊值概念网的模糊信息检索方法,在分布式网络中能进行相对较为有效的信息检索。     

人行走过程的物理分析

从人能否匀速行走,人行走过程中所受的摩擦力、功能关系以及人所受的摩擦力与动量的关系四个方面,分析了人行走过程,澄清了有关错误的概念,指出了有关文献中的不妥之处.     

除草剂农达对黄鳝致突变性研究

采用红细胞微核、核异常及染色体数目和结构畸变的方法,研究除草剂农达对黄鳝细胞的遗传毒性。结果表明,农达能引起红细胞核异常率的上升,部分组和对照组差异显,但不能明显地诱发红细胞产生微核;农达能明显地诱发黄鳝染色体数目和结构畸变率上升,和对照组差异显或极显。在一定浓度范围内,农达作用３０ｈ,对黄鳝具有明显的遗传学损伤作用。     

含负项的关联规则挖掘研究综述

关联规则挖掘是数据挖掘研究的一个重要领域,传统的关联规则仅反映了正项之间的关联关系,无法反映出数据之间隐藏的负关联关系.从以下方面对含负项的关联规则挖掘进行了综述:引入负项的原因,包含正、负项的关联规则概念及相关术语,最新的含负项关联规则研究情况,经典算法的讨论.最后,展望了含负项关联规则领域未来的研究方向.     

Detection of 4He in stratospheric particles gives evidence of extraterrestrial origin

Whipple predicted the existence of micrometeorites, small interplanetary particles which enter the Earth's atmosphere without being melted by frictional heating. During the past 2 yr, large numbers of micrometre sized stratospheric particles have been collected which are believed to be extraterrestrial, because their elemental compositions closely match those of primitive meteorites. We report here the detection of large concentrations of 4He in some of the particles. This not only suggests an exposure to solar wind, but also indicates that these particles are true micrometeorites in the sense that they were not strongly heated by entry into the atmosphere. Strong heating would have caused much of the helium to escape.     

同符号数相加“大数吃小数”的界限：理论分析

研究计算机内部二进制浮点数IEEE754存储规则及相加过程,给出数值计算中两同号规范化数相加发生“大数吃小数”现象的严格理论界限,为实际数值计算中避免此类现象提供理论依据,并利用所得理论对数值试验中的现象及结论进行解释.     

馆藏连续出版物数据库建设及质量控制

建立馆藏连续出版物数据库，为读提供计算机检索，是网络时代的必然要求．连续出版物数据库的书目数据要展示其外表特征，揭示刊名变化、出版频率变更等现象，建库工作复杂、繁琐．数据的准确性、真实性、完整性和规范化是建设高质量数据库的重要保证．本从建库的方法、程序、标准控制、规范控制、建库流程控制等方面作了阐述，并对版本、编号、附注、馆藏信息等录项目中的有关问题作了探讨．     

基于边缘概念的概念格生成算法研究

提出了一种新的基于边缘概念的概念格生成算法.通过已求出的概念内涵及外延的交集和并集运算,分层构造概念格.和已有概念格的构造算法不同的是,本算法在求出边缘概念后就不再依赖于形式背景.该算法同时解决了跨层概念间的关系.最后结合实例说明了该算法的实现过程和有效性.     

铁磁试件的力-磁效应分析和相关参数估算

为了有效地表征铁磁材料力-磁效应的磁化规律,对Langevin定律进行了修正.采用了一种新的技术处理方法,引入了有效场因子a、磁畴同向取向阻尼因子γ、磁畴场常数β、磁致伸缩与磁化强度关联系数b等基本概念,并估算了这些量数值的大小和基本的变化规律.分析了力-磁效应的基本特征,从定性和定量的角度估算了应力对试件磁化的影响.在这种模型中,说明地磁场对力-磁效应的产生具有不可缺少的作用.     

谈认知语言学在英语语法教学中的应用

以认知语言学为理论框架,采用定性描述和例证法,从概念、意义、兴趣等认知因素思考英语语法教学,认为教师应在实际教学过程中力求把抽象概念、规则具体化,让看似复杂抽象的语法现象变得浅显易懂且容易为学生接受和记住,调动学生学习语法的积极性和能动性,提高学生语法学习的效果。     

论思维的复杂系统模型暨新一代专家系统的设想

在复杂系统研究思想指导下,构建了基于神经元网络结构的复杂系统思维模型,提出以网络节点表示概念,以网络连接表示命题,以网络回路实现知识表达,以网络节点间的时空动力学激发实现演绎推理等思维活动的理论新框架,并以此为基础对新一代专家系统进行了设计。     

概念格及其应用进展

概念格是近年来获得飞速发展的数据分析的有力工具。从数据集中生成概念格的过程实质上是一种概念聚类过程。然而 ,概念格可以用于许多机器学习的任务 ,例如分类 ,关联规则的挖掘等。论文介绍了概念格的基本概念 ,讨论了现有的几种建格算法和在格上提取规则的方法及相关系统和应用。另外 ,还介绍了格的剪枝及概念格和另一个新型数据分析工具粗糙集之间的关系。     

Use of numbers by a chimpanzee

Recent studies have examined linguistic abilities in apes. However, although human mathematical abilities seem to be derived from the same foundation as those in language, we have little evidence for mathematical abilities in apes (but for exceptions see refs 7-10). In the present study, a 5-yr-old female chimpanzee (Pan troglodytes), 'Ai', was trained to use Arabic numerals to name the number of items in a display. Ai mastered numerical naming from one to six and was able to name the number, colour and object of 300 types of samples. Although no particular sequence of describing samples was required, the chimpanzee favoured two sequences (colour/object/number and object/colour/number). The present study demonstrates that the chimpanzee was able to describe the three attributes of the sample items and spontaneously organized the 'word order'.     

多状态模型的贝叶斯分析

引入模型状态、变状态模型的概念,基于贝叶斯方法,研究了线性模型多次状态变化下门限值和变状态数目的检测。这些结果用于研究2个数值例子。