分拆大偶数为两个几乎相等的素数之和

我们称n =p+q 为偶数n的最平衡哥德巴赫分拆 ,其中 p与 q均为奇素数 ,p≤ q且 |p - q|取可能的最小值。根据哥德巴赫猜想 ,对于每个大于或等于 6的偶数 ,必存在其最平衡哥德巴赫分拆。本文通过对 10 7以内的偶数进行的数值计算 ,进一步提出如下猜想 :由所有 (≥ 6的 )偶数之最平衡哥德巴赫分拆产生的三组比值 p/q ,p/n 以及 (n/2 -p) /n的均值 ,分别具有极限 1,1/2及 0。     

Falkner-Skan流空间演化的二次稳定性研究

依据Floquet理论建立三维亚谐扰动的控制方程，研究Falkner-Skan流的二次稳定性问题。采用高精度的谱方法进行数值模拟，结合边界层特性有效地配置边界条件，引入不同类型压力梯度，研究在压力梯度下的二维有限振幅的Tollmien-Schlichting（TS）波对三维亚谐扰动的产生、发展和演化的作用和影响。结果表明，顺压梯度的存在可以减缓二次不稳定的发生和演化，而逆压梯度却加速了二次不稳定性。     

TWO NEW RECOGNITION METHODS FOR SPATIAL PLANAR POLYGONS

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Mental spatial transformations of objects and perspective

This study sought evidence for the independenceof two classes of mental spatialtransformation: object-based spatialtransformations and egocentric perspectivetransformations. Two tasks were designed toselectively elicit these two transformationsusing the same materials, participants, andtask parameters: one required same-differentjudgments about pairs of pictures, while theother required left-right judgments aboutsingle pictures. For pictures of human bodies,the two tasks showed strikingly differentpatterns of response time as a function ofstimulus orientation. Moreover, acrossindividuals, the two tasks had differentrelationships to psychometric tests of spatialability. The chronometric and individualdifference data converge withneuropsychological and neuroimaging data insuggesting that different mental spatialtransformations are performed by dissociableneural systems.     

Geometric structures of frames of reference and natural language semantics

This article aims at formal specifications of reference systems in spatial cognition. It concentrates on two roles of reference systems connected to spatial language: reference systems resolving ambiguities and reference systems forming a basis for the classification of linguistic terms. Although coordinate systems are often seen as candidates for the geometric structure of reference systems, it is shown here that they do not appear in the explanations that go into the details. An analysis of the German terms vor, hinter, rechts and links (in front of, in back of, right, left) presents an alternative model for the geometric structure of spatial reference systems.     

局部空间-时间显著性的表达过程蕴涵对空间显著性的表达

建立的基于独立成分分析进行特征提取器的学习,进而模拟人类对视觉信息的局部空间-时间显著性的表达过程的计算模型,蕴涵了对局部空间显著性的有效表达;从而当据其设计为机器人主动视觉的注意机制的视线控制而用的算法,可以同一个处理过程适用于动态场景或静态场景的情形。对获自动态场景的特征提取器的频率特性的分析,揭示了此种内在的包含性的成因;算法的实验结果显示了局部空间-时间显著性表达过程对静态场景的局部空间显著性可有效表达。     

Choice zones: architecturally relevant areas of interest

A new type of area of interest (AOI) termed “choice zones” is proposed, that is relevant for eye tracking research in the built environment. Choice zones are an ex ante measure; this is in contrast to many existing definitions of AOIs which are data-driven. Choice zones are defined algorithmically using space-geometric parameters. The validity of the concept is tested against fixation data from an urban navigation experiment in which participants chose between alternative paths. Findings show that choice zones account for 90% of the fixations clusters. The merit of the measure for applied studies in built environment research is discussed.     

基于分区操作系统的实时监控工具的研究与实现

当前基于ARINC653的综合化航空电子系统的应用日益广泛,基于分区操作系统应用开发的方便性和灵活性已经成为航空电子系统需要解决的重要问题。详细阐述了基于分区操作系统的目标机监视的原理,并给出了一种可行的目标机运行监视工具AcoreScope的设计和实现方案。应用表明工具极大地改善和提高了航空电子系统的应用开发能力,为通信故障诊断和分析提供了依据。     

面向IMA的网络文件系统访问控制分析与设计

为了解决面向IMA的网络文件系统访问控制问题,分析了其中的访问控制,并提出一种访问控制的设计方案。采用网络文件锁,通过对文件的上锁和解锁,实现多个分区互斥访问远程文件;使用权限控制模块验证用户对文件的访问权限,用户通过验证后才能访问文件;日志文件记录整个访问远程文件的过程。给出了网络文件锁、权限控制和日志模块的工作原理。