基于云理论的大坝整体性态评价模型

现有的大坝整体性态评价方法以定性评价为主,主观性较强。针对这一问题,以单测点监控模型的计算值与监测仪器实测值之间的残差为基础,提出采用多测点融合残差表征大坝整体性态。结合信息熵理论研究了不同测点的残差变化规律,从而对各测点残差的融合权重进行了分配,计算了融合残差。通过对融合残差进行分布分析,利用逆向云发生器、正向云发生器建立了表征大坝不同性态的概念云,即评价标准。在此基础上,结合云相似度算法,建立了大坝整体性态的评价模型。算例表明,该模型能够有效识别大坝监测资料中的异常测值,并能够定量、客观地评价大坝整体性态,评价结果合理、可靠,可为保障大坝安全运行提供重要参考。      

On the difference in ionization properties between planar interfaces and linear polyelectrolytes

Ionizable planar interfaces and linear polyelectrolytes show markedly different proton-binding behavior. Planar interfaces protonate in a single broad step, whereas polyelectrolytes mostly undergo a two-step protonation. Such contrasting behavior is explained using a discrete-charge Ising model. This model is based on an approximation of the ionizable groups by point charges that are treated within a linearized Poisson-Boltzmann approximation. The underlying reason as to why planar interfaces exhibit mean-field-like behavior, whereas linear polyelectrolytes usually do not, is related to the range of the site-site interaction potential. For a planar interface, this interaction potential is much more long ranged if compared with that of the cylindrical geometry as appropriate to a linear polyelectrolyte. The model results are in semi-quantitative agreement with experimental data for fatty-acid monolayers, water-oxide interfaces, and various linear polyelectrolytes.     

Evaluation of research on expectancy theory predictions of employee performance.

Summarizes formulations of expectancy theory proposed by L. W. Porter and E. E. Lawler in 1968 and by V. H. Vroom in 1964. 9 field studies testing expectancy theory hypotheses using various measures of employee performance as the dependent variable are reviewed. Finally, the studies are evaluated in terms of the number of independent variables used, the measurement of these variables, and the statistical analysis performed. It is shown that the research has generally been inadequate in all 3 respects. Generally, results also show that valence, instrumentality, and role perceptions are significantly related to performance, while ability is not. Suggestions for improvement in expectancy theory research are made. (40 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evaluation of the risk of decompression disease during hypobaric decompression from the standpoint of the probability theory

Dentistry is a profession that enables us to combine adventure with the useful. By using our skill and knowledge we can, at least on a limited level, contribute to improving the health of people in third world countries. This article relates a dental volunteer trip into the heart of Africa. The rewards of this type of volunteer dentistry are lifelong memories and great satisfaction.