一种求解服务选取问题的混合蚁群算法

摘 要：为解决大规模服务选取问题，本文提出了一种混合蚁群算法（HACO）。该算法先采用动态skyline服务查询过程过滤抽象服务类相关的冗余候选服务，以大力缩减空间提高查找效率，然后利用聚类设计动态构造图来引导蚂蚁的搜索方向，从而确定局部服务选取的搜索区域；基于已经确定的局部服务选取的搜索区域，利用启发式策略选取具体的组合服务。我们采用标准的真实数据集和综合产生的数据集对我们的方法进行试验评估，以及和最近提出的相关组合服务算法进行对比。实验结果在解的质量和处理时间方面效果显著

Geochemical discrimination of tectonic environments of volcanic rocks of Yixian Formation in Jianping, western Liaoning

The volcanic rocks distributed in Pingzhuang-Machang basin of Jianping country should belongs to Yixian Formation，the volcanism may be divided into two subcycles. The volcanic rocks of Yixian Formation mainly consists of rhyolites, trachyte and trachyandesites. The geochemical characteristics indicate that the volcanic rocks belong to the high-K calc-alkaline magmatic serious. The volcanic rocks are characterized by high SiO2, Al2O3, K2O and Na2O, and comparatively low MgO and TiO2 components. The volcanic rocks are obviously enriched in large ion lithophile element elements (K, Rb, Sr, Zr, Ba, Pb, Li), and depleted in high field-strength element(HFSE) （Nb, Ti, P，Th，U，HREE）as well as compatible elements (Co, Ni, Cr, V).The volcanic rocks is rich in LREE. There is a slight negative Eu anomaly , no Ce anomaly. A detailed geochemical discrimination of selected elements allowed us to identify that the volcanic rocks of Yixian Formation mainly derived from the partial melting of lower crust materials，but has been contaminated by upper crustal materials during its ascent process in some degree. The volcanic rocks of Yixian volcanic cycle were generated in response to lithosphere inhomogeneous extension in the continental intraplate orogenic belt. They have the basic characteristics of continental intra-plate volcanic rocks.