基于SMP2的卫星区域可见性仿真分析

全球或区域可见性分析是导航系统定位、测速和授时性能仿真分析与评估的组成部分。采用基于仿真模型可移植性标准(SMP2)的模型开发与集成方法,开发导航系统仿真模型,分析伽利略卫星导航系统在中国格网的区域可见性。附带介绍了自主研发的PIM设计工具、代码生成器、SMP2运行时环境等支持SMP2标准的软件工具。基于SMP2的仿真模型开发与集成方法具有模型可重用性好、可移植性强、手工开发代码数量少、代码质量高的优点,可在卫星导航系统定位、测速、授时体制验证与精度分析工作中得到推广应用。     

Playing with molecules

Recent philosophy of science has seen a number of attempts to understand scientific models by looking to theories of fiction. In previous work, I have offered an account of models that draws on Kendall Walton’s ‘make-believe’ theory of art. According to this account, models function as ‘props’ in games of make-believe, like children’s dolls or toy trucks. In this paper, I assess the make-believe view through an empirical study of molecular models. I suggest that the view gains support when we look at the way that these models are used and the attitude that users take towards them. Users’ interaction with molecular models suggests that they do imagine the models to be molecules, in much the same way that children imagine a doll to be a baby. Furthermore, I argue, users of molecular models imagine themselves viewing and manipulating molecules, just as children playing with a doll might imagine themselves looking at a baby or feeding it. Recognising this ‘participation’ in modelling, I suggest, points towards a new account of how models are used to learn about the world, and helps us to understand the value that scientists sometimes place on three-dimensional, physical models over other forms of representation.     

Idealizations and analogies: Explaining critical phenomena

The “universality” of critical phenomena is much discussed in philosophy of scientific explanation, idealizations and philosophy of physics. Lange and Reutlinger recently opposed Batterman concerning the role of some deliberate distortions in unifying a large class of phenomena, regardless of microscopic constitution. They argue for an essential explanatory role for “commonalities” rather than that of idealizations. Building on Batterman's insight, this article aims to show that assessing the differences between the universality of critical phenomena and two paradigmatic cases of “commonality strategy”—the ideal gas model and the harmonic oscillator model—is necessary to avoid the objections raised by Lange and Reutlinger. Taking these universal explanations as benchmarks for critical phenomena reveals the importance of the different roles played by analogies underlying the use of the models. A special combination of physical and formal analogies allows one to explain the epistemic autonomy of the universality of critical phenomena through an explicative loop.     

基于模型聚类的软件可靠性混合模型研究

软件可靠性验证阶段的可靠性增长模型的建立与选择是软件可靠性工程人员长期关注的焦点.软件可靠性模型混合是解决模型适应性差、精度低的可行性方法.利用模型聚类的COBWEB算法处理失效数据,对基本分模型进行动态权重混合,以提高软件可靠性评估与预测的精度和稳健性.并利用软件工具对该方法进行模型评价.     

Self-organised criticality—what it is and what it isn’t

The last decade and a half has seen an ardent development of self-organised criticality (SOC), a new approach to complex systems, which has become important in many domains of natural as well as social science, such as geology, biology, astronomy, and economics, to mention just a few. This has led many to adopt a generalist stance towards SOC, which is now repeatedly claimed to be a universal theory of complex behaviour. The aim of this paper is twofold. First, I provide a brief and non-technical introduction to SOC. Second, I critically discuss the various bold claims that have been made in connection with it. Throughout, I will adopt a rather sober attitude and argue that some people have been too readily carried away by fancy contentions. My overall conclusion will be that none of these bold claims can be maintained. Nevertheless, stripped of exaggerated expectations and daring assertions, many SOC models are interesting vehicles for promising scientific research.     

Pictures of sounds: Wittgenstein on gramophone records and the logic of depiction

I consider the way Wittgenstein employed some kinds of sound recordings (but not others) in discussing logical form in the Tractatus logico-philosophicus. The year that Ludwig Wittgenstein was born in Vienna, 1889, nearby developments already underway portended two major changes of the coming century: the advent of controlled heavier than air flight and the mass production of musical sound recordings. Before they brought about major social changes, though, these innovations appeared in Europe in the form of children’s toys. Wittgenstein uses the fact that a symphony performance can be constructed from both a written musical score and the grooves of a gramophone record to explain what logical form is. His characterization of logical form in the Tractatus in terms of intertranslatability rather than in terms of interpretability is highlighted by reflecting on the kinds of examples of sound recordings that he did not use to illustrate the notion of logical form. There were other well known technologies for making visual records of sound at the time, but these did not serve to illustrate logical form.     

Where explanation ends: Understanding as the place the spade turns in the social sciences

Explanations implicitly end with something that makes sense, and begin with something that does not make sense. A statistical relationship, for example, a numerical fact, does not make sense; an explanation of this relationship adds something, such as causal information, which does make sense, and provides an endpoint for the sense-making process. Does social science differ from natural science in this respect? One difference is that in the natural sciences, models are what need “understanding.” In the social sciences, matters are more complex. There are models, such as causal models, which need to be understood, but also depend on background knowledge that goes beyond the model and the correlations that make it up, which produces a regress. The background knowledge is knowledge of in-filling mechanisms, which are normally made up of elements that involve the direct understanding of the acting and believing subjects themselves. These models, and social science explanations generally, are satisfactory only when they end the regress in this kind of understanding or use direct understanding evidence to decide between alternative mechanism explanations.     

Things and the archives of recent sciences

With the interest in studying science as practice came an interest in the material artefacts and things that form part of scientific activities in the laboratory, the field, the classroom, or the political arena. This shift in interest in connection with new modes of knowledge production raises new questions regarding the “archive” of science: what should be preserved and where to make it possible to reconstruct scientific practices in the desired detail? While digital media may be able to bridge some of the traditional divisions between the collection of scientific artefacts in museums and the written archival depositories, the move to performing science in silico produces new challenges in respect to establishing the material archives of current science. The paper will discuss these and related questions with special reference to the archives of the contemporary life sciences.     

欧盟创新驿站网络评价研究进展与分析维度

鉴于欧盟创新驿站网络在推动科技、经济和社会发展中发挥的巨大作用,创新驿站网络评价研究亦成为国外科技政策、技术创新以及区域经济研究的热点。分别从评价内容、评价指标,评价方法和模型维度,整理国外学者对创新驿站网络评价相关研究,最后指出评价研究的启示和未来趋势。     

一种处理遮掩的人脸特征点定位方法

AAM(Active Appearance Models,主动表观模型)是一种定位人脸特征点的有效方法,它由人脸动态表现建模和拟合算法两部分组成.在多种拟合算法中,投影式反向组合算法(Proiect-outInverse Compositional Algorithm)具有快速高效的特点.但当人脸的某部分被遮掩时,算法的精度会明显下降.提出一种采用逐层细分掩模消除干扰的正规化反向组合算法,该算法既保留了反向组合算法快速高效的优点又提高了算法处理遮掩的能力.实验结果表明:在采用标准的IMM人脸库作为训练集的情况下,当脸部被遮掩0%-30%时,算法能够保证定位特征点的标准误差值介于0.01-0.1之间.