基于非线性核脊回归算法的海洋微生物发酵参数软测量

针对海洋微生物溶菌酶发酵工艺中参数实时测量,采用根据发酵过程中主辅变量关系的相关灵敏度矩阵绝对值最大元素排序选择辅助变量,运用非线性核脊回归(NKRR)算法预测主导参数的软测量方法。相关灵敏度矩阵反映主辅变量联系,根据发酵实际实验得到。改进直接优化的非线性核脊回归算法辨识发酵非线性系统,将空间Rn中主导变量和辅助变量非线性函数映射关系转化为空间H中的线性划分,运用M ercer条件的核函数求解回归方程,避免直接计算变量映射函数及其内积。通过仿真研究和比对SVM、径向基神经网络(RBFNN)两种算法的实际运行结果表明,该软测量方法具有较好的泛化性能,实时性和准确性可以满足要求。

ANSYS在冲击(撞击)荷载作用下桥墩应力可靠度分析中的应用

基于大型通用有限元软件ANSYS概率设计系统,提出利用ANSYS概率分析功能对桥墩在冲击荷载作用下最大应力进行可靠性分析的方法。采用ANSYS的中心复合设计法,对桥墩在冲击荷载、荷载位置、弹性模量以及密度等随机变量作用下的结构可靠度进行计算,获得桥墩应力响应的可靠度指标和桥墩的失效概率,以及最大应力与各个随机变量的相关灵敏度等一系列具有重要价值的结论。

水库移民生产生活水平综合评价方法研究

移民生产生活水平的综合评价是水库移民安置及后期扶持效果评价的核心内容。基于广东省大中型水库移民后期扶持政策实施情况的监测评估调查数据,从指标遴选、分级标准、评价方法3个方面(全过程)对此进行了研究。首先,利用复相关-信息灵敏度方法从海选指标中遴选出信息重叠度低的关键指标,构建移民生产生活水平的评价指标体系;其次,由指标的数据场势值计算初始聚类中心,再根据K均值聚类法确定各指标的分级标准;最后,采用基于熵权法的综合评分法对移民的生产生活水平进行评价。根据评价结果分析比较了不同地区的后期扶持工作,结果表明,该方法与现有的移民生产生活水平评价方法相比,更加客观、合理,可为后续工作的开展提供参考意见。

Improvement of Similarity Measure： Pearson Product-Moment Correlation Coefficient

Aim To study the reason of the insensitiveness of Pearson product-momentcorrelation coefficient as a similarity measure and the method to improve its sensitivity. MethodsExperimental and simulated data sets were used. Results The distribution range of the data setsinfluences the sensitivity of Pearson product-moment correlation coefficient. Weighted Pearsonproduct-moment correlation coefficient is more sensitive when the range of the data set is large.Conclusion Weighted Pearson product-moment correlation coefficient is necessary when the range ofthe data set is large.

Sensitivity of Coupled Chaotic Dynamical System to Parameters in the Context of Data Assimilation

In this paper, a numerical modeling tool is described which can be used to explore various aspects of four dimensional variational data assimilation and parameter estimation arising in geophysical, environmental, biological and engineering sciences. A major component of this tool is a coupled chaotic dynamical system obtained by coupling two versions of the well-known Lorenz （1963） model with different time scales which differ by a certain time-scale factor. A tangent linear model and its adjoint are considered that correspond to a coupled chaotic system. The general idea of applying sensitivity measures （sensitivity functions） to coupled systems, emphasizing the data assimilation aspects, is explored as well by the forward sensitivity approach. For this purpose the set of sensitivity equations is derived from the nonlinear equations of the coupled dynamical system. To estimate the influence of model parameter uncertainties on the simulated state variables the relative error in the energy norm is used.

Uncertainty through Polynomial Chaos： A Sensor Sensitivity and Correlation Analysis in EEG Problems

The author studies the effect of uncertain conductivity on the electroencephalography （EEG） forward problem. A three-layer spherical head model with different and random layer conductivities is considered. Polynomial Chaos （PC） is used to model the randomness. The author performs a sensitivity and correlation analysis of EEG sensors influenced by uncertain conductivity. The author addressed the sensitivity analysis at three stages： dipole location and moment averaged out, only the dipole moment averaged out, and both fixed. On average, the author observes the least influenced electrodes along the great longitudinal fissure. Also, sensors located closer to a dipole source, are of greater influence to a change in conductivity. The highly influenced sensors were on average located temporal. This was also the case in the correlation analysis. Sensors in the temporal parts of the brain are highly correlated. Whereas the sensors in the occipital and lower frontal region, though they are close together, are not so highly correlated as in the temporal regions. This study clearly shows that intrinsic sensor correlation exists, and therefore cannot be discarded, especially in the inverse problem. In the latter it makes it possible not to specify the conductivities. It also offers an easy but rigorous modeling of the stochastic propagation of uncertain conductivity to sensorial potentials （e.g., making it suited for research on optimal placing of these sensors）.

相关色温测量不确定度分析

相关色温是表征光源光谱特性的重要参量,而国际上并无相关色温测量不确定度的解析公式。本文分别采用不确定度传播律法和蒙特卡罗两种方法分析相关色温的测量不确定度。对于不确定度传播律方法,从相关色温的基本定义推导给出相关色温灵敏度系数公式,进而评价相关色温测量不确定度。数值计算的相关色温随光谱功率的变化验证了相关色温灵敏度系数公式的正确性。对于蒙特卡罗方法,采用蒙特卡罗模拟生成一组光谱数据,然后计算相应的相关色温及其分布,从而得到相关色温的测量不确定度。结果表明两种方法得到的相关色温测量不确定度吻合,在不考虑光源光谱的关联时,相关色温不确定度与波长间隔的平方根近似成正比。

Anthropic considerations in nuclear physics

In this short review, I discuss the sensitivity of the generation of the light and the life-relevant elements such as carbon and oxygen under changes of the parame- ters of the Standard Model pertinent to nuclear physics. Chiral effective field theory allows for a systematic and precise description of the forces between two, three and four nucleons. In this framework, variations under the light quark masses and the electromagnetic fine-structure constant can also be consistently calculated. Combining chiral nuclear effective field theory with Monte Carlo simulations allows to further calculate the properties of nuclei, in particular of the Hoyle state in carbon, that plays a crucial role in the gener- ation of the life-relevant elements in hot, old stars. The dependence of the triple-alpha process on the fundamental constants of nature is calculated, and some implications for our anthropic view of the Universe are discussed.