基于分区进化遗传算法的无人船自导航规划研究

为解决无人船中的自导航路径规划问题,先对无人船的任务进行分层研究,再对其中的路径规划层进行分析。在完成航行环境的栅格化处理后,采用分区进化遗传算法(PEGA)对航行路径进行适应度值选取和交叉变异处理,以选出最优航行路径。实验结果表明,PEGA算法具有稳定的寻优性能,在迭代至30代时达到稳定状态,且稳定适应度值为0.58,并且该算法还能通过不同的目标需求完成不同的最优路线规划。

分区引导种群进化的拟态物理学多目标优化算法

针对基本拟态物理学优化(artificial physics optimization, APO)算法易陷入局部最优、分布性不佳等问题,提出一种分区引导种群进化的改进多目标拟态物理学优化(multi-objective APO improved by partition-guided evolution, PEMOAPO)算法。首先,采用tent映射与反向学习相结合的策略进行种群的初始化,增强种群的多样性;其次,提出分区引导个体进行进化的机制,对处于可行域与不可行域的个体,采取不同的质量函数及虚拟作用力计算规则进行迭代更新,增强算法的收敛性能。选取MW系列和C_DTLZ系列作为基准测试函数进行仿真实验,通过综合性能评价指标对比分析、统计学分析、收敛性分析及时间复杂度分析,表明改进算法具有良好的多样性及收敛性,能快速收敛到Pareto前沿。

Expression and Phylogenetic Analysis of Pea Actin Isoforms

Pea ( Pisum sativum Linn.) actin gene family contains at least three isoforms (PEAcⅠ, PEAcⅡand PEAcⅢ), and the DNA sequence of these isoforms show high similarity in the coding regions and significant divergence in the untranslated regions. RT_PCR and Southern blotting using 3′_untranslated region (3′_UTR) as specific probe revealed that pea isoactin genes were expressed in roots, stems, leaves, tendrils, pollen and juvenile siliques, but displayed different patterns of transcript accumulation. Two_fold serial dilution electrophoresis showed PEAcⅠ mRNA preferentially accumulated in rapidly developing tissues: it peaked in seven days' stem; remained at a rather high level in leaves within a month but decreased significantly later; varied a little in tendrils and reached a median and a very low level respectively in juvenile siliques and in pollen. PEAcⅡ displayed somewhat similar expression pattern to PEAcⅠ. The observed differences in sequences and transcript accumulation patterns suggest that the individual pea actin genes may differ in their transcriptional regulation and cellular function. Phylogenetic tree of actins showed that pea actin isoforms are as diverged from each other as they are from other plant actins, and pea actins might have originated from a common ancestor before the divergence of the dicot and monocot plants.

Temporal distribution of piperocks in Cambrian and Ordovician: A coevolutionary process with changes of paleoenvironment

Piperock, a kind of characteristic ichnofabrics in Phanerozoic, was thought to decline gradually from Cambrian to Ordovician. A new compilation on the occurrences of the Cambrian and Ordovician piperocks of China and the world shows that piperocks generally flourished in Cambrian and declined in Ordovician, but a sharp decrease occurred during Middle and Late Cambrian. The case-study on the piperocks from the Lower-Middle Ordovician Hongshiya Formation at Dabaochang of Qiaojia, northern Yunnan Province, Southwest China indicates that the forming and preservation of piperocks were controlled by the depositional environment, the intensities of predation, competition, bioturbation, and the contents of nutrition and oxygen in watermass. A careful study on the development of the Cambrian and Ordovician piperocks suggests that the decrease of nearshore siliciclastic sediments and the low contents of oxygen and nutrition in the watermass may have contributed to the decline of piperocks in Middle and Late Cambrian.