基于词性和改进Stacking模型的需求依赖关系提取

为解决需求工程中人工分析需求依赖关系面临的成本和效率问题,提出一种基于词性特征和改进Stacking集成学习模型(P-Stacking)的需求依赖关系提取方法。在词性权重确定过程中,提取出能表征需求句主干语义的主谓宾三元组作为3种词性,使用粒子群算法迭代计算出各词性权重,以此改进TF-IDF。P-Stacking使用相关性较小算法为基模型选择相异分类器,使用网格搜索算法匹配最优基分类器组合。实验结果表明,在3个数据集的评估测试中,分别引入词性特征和集成学习模型后,需求依赖类型预测准确性有了显著提升。

基于集成主动学习策略的需求依赖关系自动提取

由于需求依赖提取是一项认知困难且易出错的任务,因此本文提出了基于集成主动学习策略的需求依赖关系自动提取方法.基于集成主动学习策略,为不确定性概率、文本相似差异度、主动学习变体预测分歧度这3个不同角度的影响因子采用变异系数法确定相应的权重,给出衡量依赖对样本信息价值量的计算公式,从而选取综合评价值最高的前K个依赖对样本作为最优样本.随着最优样本不断加入到初始训练集中,主动学习模型提取需求依赖关系的性能快速提升,从而与其他主动学习策略相比,实现了同等采样数量下更高的需求依赖提取评估度量.最后,通过对比分析了多种方法的实验结果,证明了本方法的可行性.

基于源码解析的软件依赖网络构建研究

软件依赖网络是指代码中各个实体因相互依赖而形成的复杂网络结构。当前,大多数的研究使用商业或闭源工具构建依赖网络数据集,工具之间缺乏统一的实体依赖模型,难以进行数据交换、工具迁移和性能对比。为此,采用源码解析的方式提取依赖关系,构建软件依赖网络,并在6个开源项目上,从依赖提取和依赖强度两个方面开展实证分析,构建一个规模不等、可复现、开放、共享的依赖网络数据集,以便研究人员开展基于软件依赖网络的应用研究。

Allelopathic Potentials of Some Crop Residues on the Germination and Seedling Growth of Chromolaena Odoratum L.

The allelopathic effects of aqueous extracts of rice husk （Orza sativa L.） and sorghum stem （Sorghum bicolor L.） on the germination and seedling growth of Chromolaena odoratum L. were investigated. The extracts of the two crop residues exhibited inhibitory effects on the germination and seedling growth of Chromolaena odoratum L. The degree of retardation demonstrated in both extracts was concentration dependent. However the results obtained revealed that the retardation was more pronounced in the rice husk extract-treated seeds. However statistical analysis （P 〈 0.05% level） revealed that the degrees of inhibition of radicle and plumule obtained from various extracts treated seeds of both extracts were not significantly different when compared to those obtained from the control experiments as well as those obtained from the varying extract concentrations.

Allelopathic Potentials of Some Crop Residues on the Germination and Growth of Bidens pilosa. L.

The allelopathic potentials of the aqueous extracts of rice husk and sorghum stem were examined on the germination and growth ofBidens pilosa. L. The extracts inhibited the germination ofB. pilosa seeds and the growth lengths of its radicle and plumule. In both extracts, the severity of the inhibition increased with the increase in the concentrations of the extracts, indicating that the effects of the extracts were concentration dependent. The results obtained also showed that the degree of retardation appeared to be more pronounced in the rice husks extract-treated seeds than those of sorghum extract-treated seeds. However there were no significant differences （at 5% level） in the comparison of the degree of inhibitions of radicle and plumule growths at the varying extract concentrations as well as those of the control in both extracts treated seeds.