An experimental study on the self-adaption mechanism used by evolutionary programming

Evolutionary programming (EP) is one of the most important methods for numerical optimization. Its main technique is the combination of mutations and the self-adaption mechanism. In the past years, studies on EP focused on how to improve the efficiency of mutations with different probability distributions, and few of them touched on the question that the self-adaption mechanism did not work sometimes, but simply followed the original suggestion. So far, no experimental results have shown why this is a question. This paper firstly gives a primary analysis on the behavior of the self-adaption mechanism, and then presents experimental evidences to show why its adaptive ability is doubtful.     

An experimental study on the self-adaption mechanism used by evolutionary programming

Evolutionary programming （EP） is one of the most important methods for numerical optimization. Its main technique is the combination of mutations and the self-adaption mechanism. In the past years, studies on EP focused on how to improve the efficiency of mutations with different probability distributions, and few of them touched on the question that the self-adaption mechanism did not work sometimes, but simply followed the original suggestion. So far, no experimental results have shown why this is a question. This paper firstly gives a primary analysis on the behavior of the self-adaption mechanism, and then presents experimental evidences to show why its adaptive ability is doubtful.     

演化分析框架下企业学习模型的比较与构建

从演化角度探讨传统主流经济模型的局限,比较分析基于不同角度的学习模型.在此基础上,构建一个基于一定“噪声”条件的随机学习模型,旨在说明建立在学习基础上的企业决策行为的概率演化动态过程.结果表明,演化路径具有复杂系统演化的一般特征,但当系统演化能达到稳定状态时,可以求得一个均衡的决策行为概率分布,这一均衡分布可以作为纳什均衡的随机扩展.     

Ultimate physical limits to computation

Computers are physical systems: the laws of physics dictate what they can and cannot do. In particular, the speed with which a physical device can process information is limited by its energy and the amount of information that it can process is limited by the number of degrees of freedom it possesses. Here I explore the physical limits of computation as determined by the speed of light c, the quantum scale h and the gravitational constant G. As an example, I put quantitative bounds to the computational power of an 'ultimate laptop' with a mass of one kilogram confined to a volume of one litre.     

The limits to tree height

Trees grow tall where resources are abundant, stresses are minor, and competition for light places a premium on height growth. The height to which trees can grow and the biophysical determinants of maximum height are poorly understood. Some models predict heights of up to 120 m in the absence of mechanical damage, but there are historical accounts of taller trees. Current hypotheses of height limitation focus on increasing water transport constraints in taller trees and the resulting reductions in leaf photosynthesis. We studied redwoods (Sequoia sempervirens), including the tallest known tree on Earth (112.7 m), in wet temperate forests of northern California. Our regression analyses of height gradients in leaf functional characteristics estimate a maximum tree height of 122-130 m barring mechanical damage, similar to the tallest recorded trees of the past. As trees grow taller, increasing leaf water stress due to gravity and path length resistance may ultimately limit leaf expansion and photosynthesis for further height growth, even with ample soil moisture.     

常用遥感蒸散发模型干湿限的新定义及数值模拟

为解决目前常用遥感蒸散发模型干、湿限选取不确定性导致蒸散发反演结果存在的空间歧义性,对遥感蒸散发模型干限、湿限进行重新定义。对干湿限进行垂向一维热扩散数值模拟,以验证重新定义的干湿限能量分配假设及部分重要遥感参数取值的合理性。利用疏勒河流域地下水均衡试验场土壤剖面温度数据对干限温度进行验证,均方根误差为1.68K;利用参考作物蒸散量对湿限蒸散量进行验证,线性回归确定性系数约为0.90。研究结果表明:重新定义的干湿限推导求解方案合理,有助于避免遥感蒸散发模型中的空间歧义性。     

少数民族青少年韧性素质量表的概化分析

运用概化理论检验少数民族青少年韧性素质量表(EMARDI)的心理测量学性能,采用EMARDI对贵州、云南和四川地区的2 241名少数民族青少年进行问卷调查。结果显示:EMARDI具有较好的测量学属性,各因子(高阶与低阶因子)和全量表的概化系数和可靠性指数均达到较好水平,可作为评估我国少数民族青少年韧性素质水平的本土化测评工具;个人支持力及所属低阶因子的分量比例还不尽完善,未来开展EMARDI的修订工作,可着重考虑对该因子的题目进行修正。     

知生知死知我——“子曰：‘未知生焉知死？’”简论

“生”与“死”是孔子学说中没有明言的问题，通过遮诠的表述，孔子表达了对“生”、“死”问题上采用对象化把握方式的反对。孔子对“知生”与“知死”割裂表诠，意在通过不可言说的言说，达到对“知生”与“知死”本是同一过程的领悟。在此领悟中，此在退回到本真能在。知生即为知死，知死即为知我。     

Context Is the Key to the Understanding of Language

The article attempts to illustrate the significance of context in understanding of language.     

遗传退火进化算法在背包问题中的应用

从增强算法收敛性和减少参数依赖性的角度出发，提出应用遗传退火进化算法求解背包问题，遗传退火进化算法结合了遗传算法和模拟退火算法的优点，并有效地克服了各自的弱点，使其在优化性能、优化效率和可靠性方面具有明显的优越性．阐明了用该算法求解背包问题的具体实现过程，并通过实际数值计算和结果比较表明，该算法优于遗传算法和模拟退火算法．     

认识宇宙 -从夸克到宇宙

现代物理学特别是高能天体物理学的发展表明，极小尺度的夸克和轻子与极大尺度的宇宙有着非常紧密的联系。粒子物理学的最新研究成果被广泛地应用于宇宙学的研究。这些进展不仅引起众多相关的专家、学者的密切关注，也吸引了广泛读者的兴趣。本书作者是当前世界上能量最高的粒子物理实验室——费米实验室的著名的实验物理学家，曾经就相关课题对各种层次的听众做过上百次的讲演。感受到公众渴求了解现代物理学、天体物理学和宇宙学最新成果的热情和自己以通俗易懂的语言普及这些知识的责任，本书就是在这样的背景之下完成的。其目的就是要让人们能够更容易、更准确地了解粒子物理学的理论家和实验家们正在做些什么以及他们是如何做的。     

Nonlinear limits to the information capacity of optical fibre communications.

The exponential growth in the rate at which information can be communicated through an optical fibre is a key element in the 'information revolution'. However, as for all exponential growth laws, physical limits must be considered. The nonlinear nature of the propagation of light in optical fibre has made these limits difficult to elucidate. Here we use a key simplification to investigate the theoretical limits to the information capacity of an optical fibre arising from these nonlinearities. The success of our approach lies in relating the nonlinear channel to a linear channel with multiplicative noise, for which we are able to obtain analytical results. In fundamental distinction to linear channels with additive noise, the capacity of a nonlinear channel does not grow indefinitely with increasing signal power, but has a maximal value. The ideas presented here may have broader implications for other nonlinear information channels, such as those involved in sensory transduction in neurobiology. These have been often examined using additive noise linear channel models but, as we show here, nonlinearities can change the picture qualitatively.     

Pushing the limits of lithography

The phenomenal rate of increase in the integration density of silicon chips has been sustained in large part by advances in optical lithography--the process that patterns and guides the fabrication of the component semiconductor devices and circuitry. Although the introduction of shorter-wavelength light sources and resolution-enhancement techniques should help maintain the current rate of device miniaturization for several more years, a point will be reached where optical lithography can no longer attain the required feature sizes. Several alternative lithographic techniques under development have the capability to overcome these resolution limits but, at present, no obvious successor to optical lithography has emerged.     

从时代发展的本质趋势中正确认识社会主义

对当代社会主义事业面临的困难和挫折，本文试图通过扩展和深化对社会主义、资本主义和科学技术以及三者之间关系的认识，论证社会主义是迄今为止优于资本主义的最先进、最合理的社会制度，它将在与现代科学技术相结合中，在同资本主义的并存和竞争中最终战胜资本主义。