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1.
The capacity to generate a limitless range of meaningful expressions from a finite set of elements differentiates human language from other animal communication systems. Rule systems capable of generating an infinite set of outputs ("grammars") vary in generative power. The weakest possess only local organizational principles, with regularities limited to neighboring units. We used a familiarization/discrimination paradigm to demonstrate that monkeys can spontaneously master such grammars. However, human language entails more sophisticated grammars, incorporating hierarchical structure. Monkeys tested with the same methods, syllables, and sequence lengths were unable to master a grammar at this higher, "phrase structure grammar" level. 相似文献
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Can an ape create a sentence? 总被引：6，自引：0，他引：6
More than 19,000 multisign utterances of an infant chimpanzee (Nim) were analyzed for syntactic and semantic regularities. Lexical regularities were observed in the case of two-sign combinations: particular signs (for example, more) tended to occur in a particular position. These regularities could not be attributed to memorization or to position habits, suggesting that they were structurally constrained. That conclusion, however, was invalidated by videotape analyses, which showed that most of Nim's utterances were prompted by his teacher's prior utterance, and that Nim interrupted his teachers to a much larger extent than a child interrupts an adult's speech. Signed utterances of other apes (as shown on films) revealed similar non-human patterns of discourse. 相似文献
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Humans, but no other animal, make meaningful use of spoken language. What is unclear, however, is whether this capacity depends on a unique constellation of perceptual and neurobiological mechanisms or whether a subset of such mechanisms is shared with other organisms. To explore this problem, parallel experiments were conducted on human newborns and cotton-top tamarin monkeys to assess their ability to discriminate unfamiliar languages. A habituation-dishabituation procedure was used to show that human newborns and tamarins can discriminate sentences from Dutch and Japanese but not if the sentences are played backward. Moreover, the cues for discrimination are not present in backward speech. This suggests that the human newborns' tuning to certain properties of speech relies on general processes of the primate auditory system. 相似文献
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Psychologists, economists, and advertising moguls have long known that human decision-making is strongly influenced by the behavior of others. A rapidly accumulating body of evidence suggests that the same is true in animals. Individuals can use information arising from cues inadvertently produced by the behavior of other individuals with similar requirements. Many of these cues provide public information about the quality of alternatives. The use of public information is taxonomically widespread and can enhance fitness. Public information can lead to cultural evolution, which we suggest may then affect biological evolution. 相似文献
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基于DEM导出的水文地形参数对比研究——在ArcGIS和Rivertools环境下 总被引：1，自引：0，他引：1
对比分析了在Rivertools和ArcGIS 2种软件环境下基于DEM提取水文地形参数的差别。结果表明:Rivertools在计算DEM填洼时较ArcGIS软件好,并可自动生成多项其他的水文地形参数,使用也更为方便,但Rivertools的河网分级方法单一,河道的裁剪只能在同一河流级别下进行;而ArcGIS的河网分级方法不唯一,且河道的裁剪不受河流级别的限制,但是要求用户对研究区域的河网有相当的了解,否则在河网的自动提取中容易与实际产生较大的偏差。鉴于2种软件各自的特点,在实际应用中应将两者结合起来,充分发挥每个软件的优点。同时,本文对基于不同精度(5m×5m、10m×10m、25m×25m、50m×50m和100m×100m)DEM导出的水文地形参数(河网长度、河网密度、高程、流域面积)进行了对比分析。结果表明:在一定的DEM精度范围内,用Rivertools软件基于DEM导出的河网总长、流域面积等水文地形特征参数与实际情况吻合得更好,但DEM精度对以此导出的水文地形特征参数更为敏感,而ArcGIS环境下DEM精度对地形特征参数的影响较小。 相似文献
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提出了 Linux 下语音实时传输的一种实现方法,该方法通过调用 OSS 声卡驱动程序实现语音的采集和回放,通过调用 JRTPLIB 库实现音频流的实时传输。实验表明,通过此方法可以快速方便的实现语音的实时传输。 相似文献
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It has been found that with an oscilloscope driven through a simple network of two resistors and two capacitors it is possible to produce recognizable pictures from speech sounds. These pictures thus become a natural phonetic alphabet, with which both standard pronunciation and the nuances of dialect and accent can be represented. While a given speech sound has certain invariant characteristics, it has also an overlay of accent, which can be represented in the alphabetic character. It is suggested that the technique may be useful in teaching deaf children to speak. 相似文献
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矮丰三号小麦茎秆的力学性质初探 总被引：2，自引：0，他引：2
康福华 《西北农林科技大学学报(自然科学版)》1986,(3):17-29
我们对矮丰三号小麦茎秆的力学性质进行实测,取得各节间的强度极限、弹性模量、波松比以及不同含水率情况下的强度极限。本文分析、研究了这些表征力学性质的量值的变化范围和规律,并用图线显示其规律性,从而确定了这些量值和找出最弱节间的所在。 相似文献
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Circadian clocks are influenced by social interactions in a variety of species, but little is known about the sensory mechanisms underlying these effects. We investigated whether social cues could reset circadian rhythms in Drosophila melanogaster by addressing two questions: Is there a social influence on circadian timing? If so, then how is that influence communicated? The experiments show that in a social context Drosophila transmit and receive cues that influence circadian time and that these cues are likely olfactory. 相似文献
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Learning by rats was facilitated when response-relevant cues were provided by other rats; learning increased as a function of number of cues provided. These results suggest that rats can learn by imitation. Learning by rats that observed conspecifics not emitting response-relevant cues was retarded compared to learning by rats that did not observe conspecifics. This indicates that a conspecific's presence can also inhibit learning, a result consistent with social facilitation theory. 相似文献
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Schechter RS Chaskelis HH Mignogna RB Delsanto PP 《Science (New York, N.Y.)》1994,265(5176):1188-1192
Parallel processing has changed the way much computational physics is done. Areas such as condensed matter physics, fluid dynamics, and other fields are making use of massively parallel computers to solve immense and important problems in new ways. Simulating wave propagation is another area that has benefited through the use of parallel processing. This is graphically illustrated in this article by various numerical simulations of ultrasonic pulses propagating through solids carried out on a massively parallel computer. These computations are accompanied by visualizations of the resulting wavefield. The calculations and visualizations, together, can be completed in only seconds to several minutes and compare well with experimental data. The computations and parallel processing techniques described should be important in related fields, such as geophysics, acoustics, and mechanics. 相似文献
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A protein mixture can be separated in a flow column by application of a transverse electrophoretic field to carry faster-migrating components of the mixture into a fixed gel bed at one side of the column, so that slower components move along in a buffer stream. The field is then reversed to returnthe faster-moving components to the buffer stream. The cycle is repeated many times to complete the separation. 相似文献
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Evolution of mechanisms controlling mating behavior 总被引：4，自引：0，他引：4
The proximate mechanisms underlying mating behavior in naturally occurring species can be fundamentally different from those in more commonly studied laboratory and domesticated forms. In naturally occurring species, reproductive strategies are much more diverse, and mechanisms controlling behavior are correspondingly diverse. A variety of hormonal, environmental, and social cues can be used to activate mating behavior. Which cues are used by particular species depends on differences in environmental and physiological constraints imposed by particular reproductive strategies. Study of this diversity of mechanisms promises to identify specific selective forces that have shaped their evolution. This evolutionary perspective leads to widely applicable generalizations and provides a useful context within which to conceptualize differences between species, populations, and individuals. 相似文献
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Human visual recognition processes are remarkably robust and can function effectively even under highly degraded viewing conditions. Contextual information may play a critical role in such circumstances. Here, we provide neurophysiological evidence that contextual cues can elicit object-specific neural responses, which have hitherto been believed to be based on intrinsic cues alone. Specifically, we find that the "fusiform face area" (FFA) maintains its selectivity for faces without regard to whether the faces are defined intrinsically or contextually. This finding further elucidates the role of the FFA and reveals neural correlates of contextual processing in the service of robust object recognition. 相似文献
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吴涛 《农业图书情报学刊》2010,22(8):203-205
鉴于我国的言论自由现已达到了建国以来从未有过的程度,运用福柯的话语理论分析我院贴吧中有关图书馆的贴子,探究出我馆现存制度中的薄弱环节：宣传制度未展开;文献资源建设制度在实施中有待监控;管理制度单一。贴吧中的图书馆话语与图书馆的建设只有形成良好的互动关系,才能促进彼此的健康发展。 相似文献
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为提高声调识别率，利用隐条件随机场对汉语声调进行建模，通过加入音节内动态特征、音节间动态特征以及段长特征来进一步提高声词识别性能。提出了将声调模型加入大词汇量连续语音识别系统的区分性方法，根据最小音子错误准则区分性训练模型相关的概率权重，对声学模型及声调模型概率进行加权；给出了两种权重组合策略并通过一种平滑方法来克服权重训练过拟合的问题。实验结果表明，基于隐条件随机场声调模型能够显著提高声词识别率以及大词汇量语音识别的识别率，同时与全局模型权重方法比较，区分性的模型权重训练能够在声调模型加入连续语音识别系统之后，进一步提高系统的识别性能。 相似文献
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当前便携式农产品市场信息采集设备缺少语音接口,且通用领域的识别算法又过于复杂,为此提出一种适用于该设备作业环境的语音识别鲁棒性方法。首先利用MMSE估计器对带噪信号进行增强,以提高输入信号的信噪比;对增强后产生的语音失真和残留噪声,再利用倒谱均值方差归一化（CMVN）方法进行补偿。实验结果表明,该联合后的算法能有效的提高系统的识别率,特别是在低信噪比（0~10 dB）环境下更为有效。 相似文献
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南宁地区灰木莲人工林生长规律研究 总被引：7，自引：1，他引：6
探讨广西高峰林场46年生灰木莲人工林生长规律和林分分布规律,为合理保护和培育灰木莲人工林提供参考。以灰木莲解析木为基础,运用软件进行回归分析,建立灰木莲树高、胸径、材积数学模型,用实测值验证方程的精确性,并绘制生长曲线,对其生长规律进行分析;通过计算灰木莲人工林的径阶频率分布来分析林分的径阶分布。结果表明,建立的生长模型拟合效果好、精度高,可用于南宁地区灰木莲人工林生长过程的预测;灰木莲是早期速生、持续生长较长的树种,在0~14 a为其树高生长的速生期,14 a后生长趋慢。0~8 a为胸径生长的速生期,8 a后胸径生长减缓。材积生长到46 a仍未达到最大值,说明其成熟期在46 a后;灰木莲人工林林木株数呈正态分布,说明林分生长正常,稳定性较大。 相似文献