首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
W Bains 《Science (New York, N.Y.)》2012,337(6099):1173; author reply 1173
Grainger et al. (Reports, 13 April 2012, p. 245) suggest that baboons can discriminate words from nonwords on the basis of two-letter (bigram) frequencies. This ability can also be attributed to baboons being able to recognize specific letters (i.e., shapes) in specific positions in their four-letter words, without reference to letter or bigram frequencies.  相似文献   

2.
Visual presentation of words activates extrastriate regions of the occipital lobes of the brain. When analyzed by positron emission tomography (PET), certain areas in the left, medial extrastriate visual cortex were activated by visually presented pseudowords that obey English spelling rules, as well as by actual words. These areas were not activated by nonsense strings of letters or letter-like forms. Thus visual word form computations are based on learned distinctions between words and nonwords. In addition, during passive presentation of words, but not pseudowords, activation occurred in a left frontal area that is related to semantic processing. These findings support distinctions made in cognitive psychology and computational modeling between high-level visual and semantic computations on single words and describe the anatomy that may underlie these distinctions.  相似文献   

3.
People often are unable to report the content of ignored information, but it is unknown whether this reflects a complete failure to perceive it (inattentional blindness) or merely that it is rapidly forgotten (inattentional amnesia). Here functional imaging is used to address this issue by measuring brain activity for unattended words. When attention is fully engaged with other material, the brain no longer differentiates between meaningful words and random letters, even when they are looked at directly. These results demonstrate true inattentional blindness for words and show that visual recognition wholly depends on attention even for highly familiar and meaningful stimuli at the center of gaze.  相似文献   

4.
SENDERS JW 《Science (New York, N.Y.)》1963,141(3585):1067-1068
Three calculations of the number of different things stored in the world's libraries yield estimates from 7.5 x 10(7) to 7.7 x 10(8). At 10(5) words per volume, five letters per word, and 12 bits per letter, the information capacity used for storage is between 4.6 x 10(14) and 4.6 x 10(15) bits, and is increasing at about 2 x 10(6) bits per second.  相似文献   

5.
低空林地航拍图像拼接的改进缝合线算法   总被引:1,自引:0,他引:1  
目的图像拼接效果的优劣主要取决于图像配准和图像融合两个步骤。图像配准误差导致的错切以及图像序列间的视差导致的鬼影、重影问题可通过图像融合算法减小或消除。目前图像融合算法中最佳缝合线算法的综合效果较好, 但没有考虑到拼接图的正射效果, 并且无人机低空飞行时树高相对飞行高度比值较大, 这在获取正射影像时是不可忽略的干扰因素。传统的数字正射影像(DOM)是基于数字高程模型(DEM)对单张影像进行数字微分纠正进而拼接成整个区域的正射影像图。但是, 地形高程数据和植物的高度数据获取困难, 而恢复出来的地形和植物高度与实际数据存在误差, 造成DOM在局部边缘出现扭曲、模糊问题。本文提出一种不需要DEM数据, 仅用图像信息使拼接结果图保留正射投影的改进缝合线算法。方法首先对SURF特征检测、匹配与筛选, 用RANSAC算法求得的单应性矩阵确定相邻图像重叠区域; 然后基于重叠区中像素点位置与相邻两图像中心点位置的距离差可以反映正射效果的思想, 将距离差引入能量函数, 同时设计了动态权值参数用来平衡颜色、结构和距离三者的重要程度, 利用动态规划思想搜索得到最佳缝合线; 最后在缝合线两侧进行多频带融合生成类似正射影像的无缝拼接图。结果实验图像来源于不同样地、不同飞行高度, 在相邻两幅图像以及同一条带航线图像上将本文的改进缝合线算法与其他3种缝合线算法以及Pix4D生成的数字正射影像进行对比。实验结果表明, 本文提出的缝合线改进算法能保留正射投影, 视觉效果优于现有的缝合线算法, 在城镇建筑图像的实验中局部效果优于Pix4D。结论本文针对无人机低空林地航拍图像拼接重影问题和拼接结果由于视角不同而产生非正射影像区域的问题, 实现了一种不需要DEM数据进行数字微分纠正但能生成类似正射影像效果的改进缝合线算法。实验结果显示, 本文算法优于目前的最佳缝合线算法, 能够保留正射投影, 效果类似DOM, 并且在保证物体边缘清晰方面优于目前商用软件生成的DOM。这有利于更准确地计算林地的郁闭度, 估算林地植被覆盖面积, 对跟踪识别地表动植物也具有一定的帮助。除林地图像之外, 本方法也可以推广到其他需要保留正射投影的低空航拍拼接应用领域, 如城镇航拍图像等。   相似文献   

6.
Visual and auditory information processing in children and adults   总被引:3,自引:0,他引:3  
Children of three ages were compared with adults in a recognition experiment requiring continuous processing of information. The growth in precision for visually presented words is steeper than for auditorially presented words, largely because the former are harder for the first graders and, to a lesser extent, for the third graders. In adults, visual processing of information is at least as good as auditory. The use of receiver operating characteristic curves in describing the data permit greater precision in estimating the capacity of the individual subjects and are particularly useful since the errors of failure to recognize were different from ordinary errors of false recognition, and they occurred in large numbers.  相似文献   

7.
Effects of thiopental sedation on learning and memory   总被引:1,自引:0,他引:1  
Subjects who were administered thiopental showed a loss of memory for events discussed while they were under sedation. We tested the subjects for recognition memory of pictures and recall of associated pairs of letters and words, and found that the subsequent memory loss was correlated with the concentration of thiopental in the venous blood at the time the material was learned. Retention did not appear to be state-dependent because the subject, while under sedation, could recall material learned prior to sedation, and because recall was not facilitated by reinstatement of the sedation.  相似文献   

8.
农户种植茉莉花经济效益的影响因素分析   总被引:1,自引:0,他引:1  
对影响农户种植茉莉花经济效益的因素进行了实证分析.结果表明,农户种植茉莉花的经济效益的主要影响因素是:花价格、销售季节、产量、加工流通、农资价格、市场信息.影响因素权重依次为:花价格>销售季节>产量>加工流通>农资价格>市场信息.根据研究结论,就如何保护和提高农户种植茉莉花的经济效益提出了相应的对策与建议.  相似文献   

9.
Humans routinely classify others according to both their individual attributes, such as social status or wealth, and membership in higher order groups, such as families or castes. They also recognize that people's individual attributes may be influenced and regulated by their group affiliations. It is not known whether such rule-governed, hierarchical classifications are specific to humans or might also occur in nonlinguistic species. Here we show that baboons recognize that a dominance hierarchy can be subdivided into family groups. In playback experiments, baboons respond more strongly to call sequences mimicking dominance rank reversals between families than within families, indicating that they classify others simultaneously according to both individual rank and kinship. The selective pressures imposed by complex societies may therefore have favored cognitive skills that constitute an evolutionary precursor to some components of human cognition.  相似文献   

10.
11.
信息时代下,苹果产业的"资源仓库"是科技发展的重要保障。为了实现资源的深层次利用,就必须对其进行整合。以我国现有的苹果数据库、数据平台、网站、实体机构及纸质文献为数据源来构建数据库,包括生产数据库、种质资源数据库、育种数据库、栽培数据库、采后加工数据库、产业经济数据库、基础数据库、叙词库9个部分。通过知识抽取、标引和关联构建来实现数据的深加工和整合,形成新的知识库后将知识产品输出可以提供基于数据整合的相关服务。基于架构设计进行本地测试,通过具体案例演示证明和实现了我国苹果产业数据资源分布的分析、相关检索词整合和高频词整合。基于检索词进行检索后可以实现以其为中心的数据整合和知识整合,展示出知识之间的关联,挖掘出数据间的多维度知识关联关系。苹果产业科学数据整合的框架设计,可以将我国苹果产业多源化、多类型的数据融合到一起,打通数据之间的关联关系,使各类数据交织渗透。数据经过整合后可以提供更深层次的知识服务,减少了获取数据的知识成本。  相似文献   

12.
提高科技论文关键词标引质量的探讨   总被引:1,自引:0,他引:1  
在参考前人研究成果的基础上,结合我国相关标准和规范,对关键词的标引方法进行了讨论,认为关键词的标引主要是受控标引,但允许自由词的存在,其标引步骤为:论文审读→主题分析→抽词→规范化处理→标引结果审核。重点叙述了科技论文主题分析和主题词抽词技术,探讨了如何提高关键词的标引质量:科技论文主题分析要全面、规范化处理抽取的主题词,控制自由词数量。  相似文献   

13.
This paper selected the corn processing industry technology innovation alliance in Heilongjiang Province as the research object, evaluated the operational performance of the alliance by using analytic hierarchy process (AHP) and fuzzy comprehensive evaluation methods. AHP empirical results showed that the satisfaction of information communication and the satisfaction of the management process were the weakest. And the order from high to low on the level of indicators of the impact for the alliance was the result of alliance operations and the process of alliance operations, the behavioral attitude of alliance members. Besides, the results of fuzzy comprehensive evaluation showed that the operational performance of the corn processing industry technology innovation alliance in Heilongjiang Province was in the general level.  相似文献   

14.
这一组文章根据一次讨论发言写成。几名硕士研究生对近年来引起了社会广泛关注的汉语运用方而存在的问题进行调查、分析,大体上说出了这方而的主要问题:念错字,用字母标注商标存在某些混乱现象;不明词语的意义和语法功能造成词语使用不当;随意搭配词语;某些汉译作品中存在着一些语法或修辞方面的毛病。经过讨论,共同的着法是,出现这 些问题的根本原因一是语言学习不够、教育不够;二是有些人社会责任感不强。因此,呼吁加强汉语学习,要以高度的社会责任感对待汉语运用问题。  相似文献   

15.
为了阐明生物制剂在草本纤维质农产品加工业中应用的研究范围与进展,采用系统信息学技术原理,围绕生物制剂在脱胶、纺织、造纸、轻工制造等学科领域中应用的主线,对近40年的相关研究报道进行分类整理与凝练。分析结果表明,在草本纤维原料脱胶及其类似初级加工过程中应用菌制剂具有节能、减排、降耗、高效利用资源等优点;在草本纤维纺织、造纸、轻工制造等深加工领域里应用酶制剂可以充分发挥酶的专一性、高效性作用,说明生物制剂在草本纤维质农产品加工业中应用的前景十分广阔。  相似文献   

16.
Letters from John Darsee and two Emory University faculty members with whom he co-authored papers will appear in the 9 June 1983 issue of the New England Journal of Medicine. The letters will retract articles containing inaccurate and fabricated information that were published by the journal in 1979 and 1981. Darsee's letter of apology will clear his co-authors of any responsibility for the inaccuracies.  相似文献   

17.
为了合理利用电子资源为科研工作服务,就提高信息检索效率的方法进行了探讨,认为合理选择数据资源,选择合适的检索词,合理运用检索规则调整检索范围等是提高检索效率的有效方法。  相似文献   

18.
分别选择浑善达克沙地西部、中部和腹地3个区域,利用遥感影像的假彩色合成、比值增强、归一化植被指数(NDVD、掩膜技术等遥感图像增强处理技术,对3个区域进行遥感数字图像处理,探讨增强草原沙漠化信息的有效方法。研究发现:NDVI图像中,不同级别的草原沙漠化在灰阶上易于区分,尤其是轻度沙漠化和重度沙漠化,反差非常大;TM3/TM4比值运算增强了沙漠化信息,特别是半固定沙地的信息,再与原图像中的TM4和TM5进行假彩色合成,形成含有比值运算信息的合成图像,更加突出了草原中度沙漠化的信息。  相似文献   

19.
英语短语from…to…可以和表示时间、地点、次序、地位、价格、年龄、数字、重量等不同意义的词连用 ,表示从一起点到一终点。本文就其后所接之词的异同进行了总结  相似文献   

20.
以洋常春藤叶片为材料,采用同源RT–PCR方法,克隆获得了洋常春藤法呢基焦磷酸合成酶基因,其c DNA序列大小为1 050 bp,开放阅读框为1 026 bp,推测编码342个氨基酸残基,该序列的核苷酸、氨基酸与五加科植物有同源性;用在线数据软件进行分析,推测该蛋白可能存在于细胞质之中,定位在细胞膜外,FPS蛋白的相对分子质量为39 735.7;该蛋白含有2个天冬氨酸保守结构域,其二级结构主要以α螺旋和无规则卷曲为主;双子叶植物系统进化树分析结果表明,洋常春藤的FPS与刺五加、人参、三七、西洋参、辽东楤木的FPS亲缘关系最近,这一结果符合传统的分类法规则。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号