基于等级结构的竞争种群系统的最优控制问题

研究了一类基于个体等级结构差异的竞争种群系统最优控制问题。首先利用不动点定理证明了系统解的存在惟一性,其次证明了解对控制变量的连续依赖性,最后通过共轭系统及切锥-法锥的相关理论得出了最优控制的必要性条件。     

Collaborative explanation,explanatory roles,and scientific explaining in practice

Scientific explanation is a perennial topic in philosophy of science, but the literature has fragmented into specialized discussions in different scientific disciplines. An increasing attention to scientific practice by philosophers is (in part) responsible for this fragmentation and has put pressure on criteria of adequacy for philosophical accounts of explanation, usually demanding some form of pluralism. This commentary examines the arguments offered by Fagan and Woody with respect to explanation and understanding in scientific practice. I begin by scrutinizing Fagan's concept of collaborative explanation, highlighting its distinctive advantages and expressing concern about several of its assumptions. Then I analyze Woody's attempt to reorient discussions of scientific explanation around functional considerations, elaborating on the wider implications of this methodological recommendation. I conclude with reflections on synergies and tensions that emerge when the two papers are juxtaposed and how these draw attention to critical issues that confront ongoing philosophical analyses of scientific explanation.     

大规模互联网图像检索与模式挖掘

在互联网时代,爆炸式增长的数字图像不仅给图像检索带来巨大的技术挑战,同时也带来了很多机遇和研究问题的新思路．本文简单回顾了图像检索的三个阶段的研究历史．以及在此过程中数据量的增多给图像检索带来的影响,并对作为关键问题的特征提取方面的研究进行了深入的分析．本文尤其指出视觉模式挖掘是寻找中层特征表示并缩小语义鸿沟的重要研究方向,并根据视觉模式的表征粒度将其分为五种类别分别进行了介绍,从中可以看到大数据对于视觉模式挖掘的重要作用．     

The effect of target function on the predictive performance of the two‐stage ridge estimator

The main thrust of this study is to consider the problem of simultaneous prediction of actual and average values of the simultaneous equations model through the target function of Shalabh (Bulletin of International Statistical Institute, 1995, 56, 1375–1390). We focus on the predictive performance of the two‐stage ridge estimator with the motivation for eliminating the disorder arising from multicollinearity. An optimal biasing parameter of the two‐stage ridge estimator is derived by a minimization process of prediction mean square error. In addition, an optimal estimator for the weight of observed value in target function is attained theoretically. The results inferred from a numerical example and a Monte Carlo experiment provide a dramatic improvement in the predictive ability of the two‐stage ridge estimator.     

常微分方程线性系统的一般理论与方程求解

在常微分方程的全部内容中,线性系统部分占有特别重要的地位,这不仅因为其自身的理论已被研究得十分清楚外,同时线性系统又是讨论非线性系统的基础.利用线性空间理论进一步对常微分方程线性内容及方程求解做一些分析和探究.     

新混沌系统的动力学分析及计算机仿真

构造了一类新的含有包含绝对值的非线性项的三维二次自治混沌系统,根据稳定性理论分析了系统的定性行为,并借助Matlab软件进行了数值模拟,得到了系统的部分动力学特性。通过Lyapunov指数谱讨论了系统参数对系统混沌特性的影响,结果表明随着系统参数的变化,系统的动力学行为也发生了变化。进一步通过分岔图、Poincare截面图以及相图验证了上述结论。     

一类参数不确定系统的鲁棒控制及仿真

考虑具有大运行范围飞控系统的鲁棒控制问题.基于最佳拟合的方法,建立了适合大运行范围的飞行控制系统模型,从而将其转化为一类与摄动参数呈多项式函数关系的不确定性模型.对某模型飞机控制系统,采用文中鲁棒控制方法,对其进行了鲁棒镇定控制设计,仿真结果表明了文中方法的可行性.     

刚弹多体系统的姿态控制与稳定性

建立了刚弹多体系统主动控制动力学与数学模型,给出了系统的控制律,进而研究了控制与镇定问题,得到受控系统姿态指数渐近稳定性.     

建筑构件多功能耐火试验炉的设计

为了适应多种建筑构件耐火试验,并提高试验的可靠性,根据GB/T9978—1999标准的要求,设计了水平建筑构件耐火试验炉和垂直建筑构件耐火试验炉各一座.通过合理布置燃烧器,使炉内的温度更均匀,利用自行设计的控制系统对炉内的温度及压力进行自动控制,克服了传统人工操作的各种缺点,同时也减少了污染,节省了空间,节约了燃料及人工成本.最后介绍了试验炉的使用情况,取得了较好的效果.