一种用于Web服务合成过程建模的不确定性事件代数方法

 Web服务合成是目前的研究热点之一，是Web服务架构中的重要组成部分.Web服务合成过程模型用以描述Web服务合成中各服务组件应该满足的语义约束信息，是自动服务发现及合成的基础.以事件代数作为支撑理论，旨在为Web服务合成过程建模提供一种支持语义表示及推理的形式化方法.针对Web服务合成的特点及合成过程本身具有的不确定性，首先基于统计学习的思想对传统事件代数进行不确定性扩展，给出Web服务不确定事件代数(WSUEA)的定义、操作及语义，进而对服务合成中的顺序、分支及并行等基本情形分别给出其WSUEA表达式、以及相应的概率计算方法.实验验证了所提出方法的有效性.

Studies on allelopathy of aquatic macrophytes on Synahocystis sp

Allelopathy of culture water from ten kinds of macrophytes on Synahocystis sp． was investigated． The results sh owed that there was slightly stimulation effect for Ottelia acuminate cultur e water on Synahocystis sp．, while significant inhibition effects of other nine mac rophytes on the algae were performed, and their inhibition capability was as fol lowing: Maquaticum>Ecrassipes>Cdemersum >Pstratiotes >Npeltatum>Ms picatum> Hverticillata>Dsanderiana>Vspiralis, the inhibition ratio of Maquaticum on Synahocystis sp． is up to 899%． By analyzing the abs orption spectral curve and the characteristic peaks of Synahocystis sp． cel l, it was found that Maquaticum，Eichhornia crassipes and Cdemersum could secrete some allelochemicals, which destroyed the chlorophyll a and phycob iliprotein absorption peak, and disturbing the course of light-harvesting of S ynahocystis sp．． It probably indicated that allelopathic co mpounds released by macrophytes restrain the photosynthetic system of algae, whi ch was one of importance ways for macrophytes inhibiting or even killing algae．