具有多故障模式的混杂双设备生产线系统性能分析研究

研究了一个不可靠混杂双设备生产线系统。对此系统而言,每台设备可以出现多种故障模式,并且缓冲区也可能发生故障。在离散模型的基础上,分析了系统状态概率的变迁情况,给出了相应的求解方法及算法,探讨并发展了一种评价多故障混杂生产线系统性能的近似解析方法。仿真结果证明了该方法的有效性。     

Forecasting Performance of Nonlinear Models for Intraday Stock Returns

We studied the predictability of intraday stock market returns using both linear and nonlinear time series models. For the S&P 500 index we compared simple autoregressive and random walk linear models with a range of nonlinear models, including smooth transition, Markov switching, artificial neural network, nonparametric kernel regression and support vector machine models for horizons of 5, 10, 20, 30 and 60 minutes. The empirical results indicate that nonlinear models outperformed linear models on the basis of both statistical and economic criteria. Specifically, although return serial correlation receded by around 10 minutes, return predictability still persisted for up to 60 minutes according to nonlinear models, even though profitability decreases as time elapses. More flexible nonlinear models such as support vector machines and artificial neural network did not clearly outperform other nonlinear models. Copyright © 2011 John Wiley & Sons, Ltd.     

What could be objective about probabilities?

The basic notion of an objective probability is that of a probability determined by the physical structure of the world. On this understanding, there are subjective credences that do not correspond to objective probabilities, such as credences concerning rival physical theories. The main question for objective probabilities is how they are determined by the physical structure.In this paper, I survey three ways of understanding objective probability: stochastic dynamics, humean chances, and deterministic chances (typicality). The first is the obvious way to understand the probabilities of quantum mechanics via a collapse theory such as GRW, the last is the way to understand the probabilities in the context of a deterministic theory such as Bohmian mechanics. Humean chances provide a more abstract and general account of chances locutions that are independent of dynamical considerations.     

Varieties of noise: Analogical reasoning in synthetic biology

The picture of synthetic biology as a kind of engineering science has largely created the public understanding of this novel field, covering both its promises and risks. In this paper, we will argue that the actual situation is more nuanced and complex. Synthetic biology is a highly interdisciplinary field of research located at the interface of physics, chemistry, biology, and computational science. All of these fields provide concepts, metaphors, mathematical tools, and models, which are typically utilized by synthetic biologists by drawing analogies between the different fields of inquiry. We will study analogical reasoning in synthetic biology through the emergence of the functional meaning of noise, which marks an important shift in how engineering concepts are employed in this field. The notion of noise serves also to highlight the differences between the two branches of synthetic biology: the basic science-oriented branch and the engineering-oriented branch, which differ from each other in the way they draw analogies to various other fields of study. Moreover, we show that fixing the mapping between a source domain and the target domain seems not to be the goal of analogical reasoning in actual scientific practice.     

应用于微结构制造自治系统的流水线作业调度

在微结构制造自治系统中,作业调度起到至关重要的作用。当前大多数的IC作业调度都是基于组合优化技术的,与以往这些工作不同,本文提出了一种新的基于流水线的调度方案。流水线对于串行作业来说能够达到最佳的运行效率,因此获取最优调度方案问题的关键即在于对IC制造设施进行配置,使之成为流水线。本文对于流水线调度的基本算法进行了讨论。对一个实例进行了基于流水线技术的调度,结果表明多数机器都能够达到100%的最高运行效率。本文所开发的一个调度模拟程序,除了对流水线运行的情况进行模拟外,还能够用作实际的调度器,进行最优化作业调度。     

The Assembly of Geophysics: Scientific Disciplines as Frameworks of Consensus

What makes any investigative field a scientific discipline? This article argues that disciplines are ever-changing frameworks within which scientific activity is organised. Moreover, disciplinarity is not a yes or no proposition: scientific activities may achieve degrees of identity development. Degree of consensus is the key, and consensus on many questions (conceptual, methodological, institutional, and social) varies among sciences. Lastly, disciplinary development is non-teleological. Disciplines pass through no regular stages on their way from immature to mature status, designations articulated within the rhetoric of discipline formation. Scientists assemble disciplines using many elements: phenomena, methods, instruments, theories, analytical techniques, and institutional tools such as journals, government bureaus, and university positions. Scientists created geophysics during the nineteenth and twentieth centuries through such a combination. Whether geophysics became a discipline depends on how discipline is defined.     

基于移动设备云迁移的节能决策算法

随着云计算的兴起,云迁移计算开始成为移动设备获取计算资源和降低功耗的有效方式.云迁移的主要想法是将移动终端的复杂任务经由无线网络迁移到云端执行,然后再接收计算结果.然而,无线网络的不稳定性和数据传输的高功耗限制了云迁移计算在移动设备中的应用.不同于已有工作,本文通过引入数据压缩的方法完善了云迁移计算决策模型,并且基于对未来时段网络期望的预测,提出了一种节能迁移计算决策算法——EPVAD.基于实际的3G网络带宽数据和开发测试平台,实验结果显示:EPVAD算法的节能效果较同类算法平均优14.9%,并且算法自身的系统开销可忽略.     

基于虚拟样机技术的宽幅数字喷墨打印机协同仿真研究

针对宽幅数字喷墨打印机设计要求,基于ADAMS和MATLAB,联合建立了打印机协同仿真虚拟样机模型.对比试验显示喷印头速度误差在0.8％以内,吻合度较好.结果表明,该方法有效可行,为打印机的优化、样机的试制,提供了技术依据和现代化方法.     

Flow signaling and atherosclerosis

Atherosclerosis rarely develops in the region of arteries exposed to undisturbed flow (u-flow, unidirectional flow). Instead, atherogenesis occurs in the area exposed to disturbed flow (d-flow, multidirectional flow). Based on these general pathohistological observations, u-flow is considered to be athero-protective, while d-flow is atherogenic. The fact that u-flow and d-flow induce such clearly different biological responses in the wall of large arteries indicates that these two types of flow activate each distinct intracellular signaling cascade in vascular endothelial cells (ECs), which are directly exposed to blood flow. The ability of ECs to differentially respond to the two types of flow provides an opportunity to identify molecular events that lead to endothelial dysfunction and atherosclerosis. In this review, we will focus on various molecular events, which are differentially regulated by these two flow types. We will discuss how various kinases, ER stress, inflammasome, SUMOylation, and DNA methylation play roles in the differential flow response, endothelial dysfunction, and atherosclerosis. We will also discuss the interplay among the molecular events and how they coordinately regulate flow-dependent signaling and cellular responses. It is hoped that clear understanding of the way how the two flow types beget each unique phenotype in ECs will lead us to possible points of intervention against endothelial dysfunction and cardiovascular diseases.     

月球车实时遥操作方法研究

在月球探测任务中,利用无人月球车在月面移动,对一定范围的月面环境进行探测,是一种较为安全的方式.月球车的月面巡视是一个以轮地交互为基础、地面实时监视控制的过程.根据恢复的月面三维地形环境,地面进行探测目标选择和巡视路径规划,以远程控制的方式控制月面巡视.本文提出了一种月球车在线控制方式,基于虚拟现实技术,对月面地形环境和月球车状态进行运动学和视景仿真,地面控制人员通过人机交互,控制虚拟月球车行进,控制信号经验证后生成月球车的控制指令,实现月球车的在线控制.为应对地月通讯延时问题,采用预测显示方法,避免了大延迟的影响.本方法减少了控制环节,提高了月球车远程控制的效率和安全性.     

近自然森林经营目标树作业体系辅助设计系统的研究与开发

目标树林分作业体系是近自然森林经理计划中规定本经理期内对当前林分执行具体作业的林分作业模式.近自然的目标树作业体系设计是以单株木为对象,按调整林木竞争或互助的生态关系、降低作业成本、提高生产能力的原则进行,设计的技术要求较高,工作量大,结果也会因具体林分条件不同而出现较大的差异.开发一个近自然林分作业辅助设计系统是导引近自然森林经营向规范化和标准化方向进行的必要工作.本文以此为目标,以天保工程区天然林和人工林的样地调查数据为基础,以模块化设计思想为指导,采用C/S结构的系统开发模式、用Access提供数据管理并以Excel支持结果输出、以VB 6.0为程序设计语言,开发了可视化的目标树林分作业辅助设计系统.该系统实现了虚拟的林木分类标记、干扰木采伐操作及保护促进天然更新标识等作业设计内容,并提供了样地数据管理、林木空间位置分布图制作、林分统计图表和主要经营参数的自动计算和设计文本输出功能,实现了林分作业的规范化和自动化辅助设计和决策分析目标.该系统的应用可促进近自然森林经营工作规范化推广发展.     

Energy consumption,survey data and the prediction of industrial production in Italy: a comparison and combination of different models

We investigate the prediction of italian industrial production and first specify a model based on electricity consumption showing that the cubic trend in such a model mostly captures the evolution over time of the electricity coefficient, which can be well approximated by a smooth transition model, with no gains in predictive power. We also analyse the performance of models based on data of two different business surveys. According to the standard statistics of forecasting accuracy, the linear energy‐based model is not outperformed by any other model, nor by a combination of forecasts. However, a more comprehensive set of evaluation criteria sheds light on the relative merit of each individual model. A modelling strategy which makes full use of all information available is proposed. Copyright © 2000 John Wiley & Sons, Ltd.     

On Kepler's awareness of the problem of experimental error

This paper is an account of Kepler's explicit awareness of the problem of experimental error. As a study of the Astronomia nova shows, Kepler exploited his awareness of the occurrences of experimental errors to guide him to the right conclusion. Errors were thus employed, so to speak, perhaps for the first time, to bring about a major physical discovery: Kepler's laws of planetary motion. ‘Know then’, to use Kepler's own words, ‘that errors show us the way to truth.’ With a survey of Kepler's revolutionary contribution to optics, the paper demonstrates that Kepler's awareness of the problem of experimental error extended beyond discrepancies between calculations and observations to types of error which pertain to observations and instruments. It emerges that Kepler's belief in the unity of knowledge and physical realism, facilitated—indeed created—the right philosophical posture for comprehending the problem of error in an entirely novel way.     

Biomimetic actuators: where technology and cell biology merge

The structural and functional analysis of biological macromolecules has reached a level of resolution that allows mechanistic interpretations of molecular action, giving rise to the view of enzymes as molecular machines. This machine analogy is not merely metaphorical, as bio-analogous molecular machines actually are being used as motors in the fields of nanotechnology and robotics. As the borderline between molecular cell biology and technology blurs, developments in the engineering and material sciences become increasingly instructive sources of models and concepts for biologists. In this review, we provide a--necessarily selective--summary of recent progress in the usage of biological and biomimetic materials as actuators in artificial environments, focussing on motors built from DNA, classical cellular motor systems (tubulin/kinesin, actin/myosin), the rotary motor F1F0-ATPase and protein-based 'smart' materials.     

Quantum reality: A pragmaticized neo-Kantian approach

Despite remarkable efforts, it remains notoriously difficult to equip quantum theory with a coherent ontology. Hence, Healey (2017, 12) has recently suggested that “quantum theory has no physical ontology and states no facts about physical objects or events”, and Fuchs et al. (2014, 752) similarly hold that “quantum mechanics itself does not deal directly with the objective world”. While intriguing, these positions either raise the question of how talk of ‘physical reality’ can even remain meaningful, or they must ultimately embrace a hidden variables-view, in tension with their original project. I here offer a neo-Kantian alternative. In particular, I will show how constitutive elements in the sense of Reichenbach (1920) and Friedman (1999, 2001) can be identified within quantum theory, through considerations of symmetries that allow the constitution of a ‘quantum reality’, without invoking any notion of a radically mind-independent reality. The resulting conception will inherit elements from pragmatist and ‘QBist’ approaches, but also differ from them in crucial respects. Furthermore, going beyond the Friedmanian program, I will show how non-fundamental and approximate symmetries can be relevant for identifying constitutive principles.     

Forecasting the Dubai financial market with a combination of momentum effect with a deep belief network

Applying recent advances in machine learning techniques, we propose a hybrid model to forecast the Dubai financial market general index. Particularly, we exploit a deep belief networks model that applies a restricted Boltzmann machine as its main component in combination with momentum effects. We also introduce an innovative way of selecting the inputs by using momentum effects. With this hybrid methodology we generate a prediction model along with a comparison of three different linear models. The results obtained from the hybrid model are better and more stable than the three linear models. The findings support that the hybrid model we applied will find their way into finance because of their reliability and good performance.     

The birth of classical genetics as the junction of two disciplines: Conceptual change as representational change

The birth of classical genetics in the 1910's was the result of the junction of two modes of analysis, corresponding to two disciplines: Mendelism and cytology. The goal of this paper is to shed some light on the change undergone by the science of heredity at the time, and to emphasize the subtlety of the conceptual articulation of Mendelian and cytological hypotheses within classical genetics. As a way to contribute to understanding how the junction of the two disciplines at play gave birth to a new way of studying heredity, my focus will be on the forms of representation used in genetics research at the time. More particularly, I will study the design and development, by Thomas H. Morgan's group, of the technique of linkage mapping, which embodies the integration of the Mendelian and cytological forms of representation. I will show that the design of this technique resulted in a genuine conceptual change, which should be described as a representational change, rather than merely as the introduction of new hypotheses into genetics.     

Space and Time in Particle and Field Physics

Textbooks present classical particle and field physics as theories of physical systems situated in Newtonian absolute space. This absolute space has an influence on the evolution of physical processes, and can therefore be seen as a physical system itself; it is substantival. It turns out to be possible, however, to interpret the classical theories in another way. According to this rival interpretation, spatiotemporal position is a property of physical systems, and there is no substantival spacetime. The traditional objection that such a relationist view could not cope with the existence of inertial effects and other manifestations of the causal efficacy of spacetime can be answered successfully. According to the new point of view, the spacetime manifold of classical physics is a purely representational device. It represents possible locations of physical objects or events; but these locations are physical properties inherent in the physical objects or events themselves and having no existence independently of them. In relativistic quantum field theory the physical meaning of the spacetime manifold becomes even less tangible. Not only does the manifold lose its status as a substantival container, but also its function as a representation of spacetime properties possessed by physical systems becomes problematic. ‘Space and time’ become ordering parameters in the web of properties of physical systems. They seem to regain their traditional meaning only in the non-relativistic limit in which the classical particle concept becomes approximately applicable.     

Probability in 1919/20: the von Mises-Pólya-Controversy

The correspondence between Richard von Mises and George Pólya of 1919/20 contains reflections on two well-known articles by von Mises on the foundations of probability in the Mathematische Zeitschrift of 1919, and one paper from the Physikalische Zeitschrift of 1918. The topics touched on in the correspondence are: the proof of the central limit theorem of probability theory, von Mises' notion of randomness, and a statistical criterion for integer-valuedness of physical data. The investigation will hint at both the fruitfulness and the limits of several of von Mises' notions such as ``collective', ``distribution' and ``complex adjuncts' (characteristic functions) for further developments in probability theory and in ``directional statistics'. By pointing to the selectiveness of Pólya's criticism, the historical analysis shows the differing expectations of the two men with respect to the further development of the theory of probability and its applications. The paper thus gives a glimpse of the provisional state of the theory around 1920, before others such as P. Lévy (1886–1971) and A. N. Kolmogorov (1903–1987) stepped in and created a new paradigm for probability theory.