基于偏序关系的Rough集模型及其应用

在标准Rough集理论的指导下,利用偏序关系性质构造了不同分类,并以此为基础探讨了上、下近似集,从而构建了基于偏序关系的Rough集模型。新模型将Rough集理论的应用范围由等价关系扩展到偏序关系。为了更好地增强模型的实用性和灵活性,一方面从程度、精度、概率等角度出发分别对其进行了扩展,另一方面引入依赖度使其适用于研究各种非严格的偏序关系。给出了实例分析,并结合现实生活中的现象阐述了模型的应用价值。

Phylogenetic Relationships Among Species Subgroups in the Drosophila saltans Group (Diptera: Drosophilidae): Can Morphology Solve a Molecular Conflict?

Proper phylogenetic reconstruction is crucial for understanding many evolutionary phenomena. In spite of the great success of molecular phylogenetics, DNA signal still may be limited by some intrinsic constraints such as codon usage bias. The phylogenetic relationships between the five species subgroups of the Drosophila saltans group are a good example of conflicting molecular phylogenies drawn from different genes due to an ancestral substitutional shift. Here, forty morphological characters were analyzed using the same set of species used in previous molecular studies, with at least a single representative of each subgroup. The cladistic analysis was in disagreement with most of the previous hypotheses in placing the sturtevanti subgroup as an early branch, whereas the four remaining subgroups form a well supported clade that can be further subdivided into two sister clades： one containing the cordata and the elliptica subgroups, whereas the second includes the parasaltans and the saltans subgroups. The molecular evolution （codon usage bias） of the saltans group were revised in light of the present finding. The analysis highlights the important role of morphology in phylogeny reconstruction and in understanding molecular evolutionary phenomena.

Residents'Satisfaction with Public Services in Mountainous Areas:An Empirical Study of Southwestern Sichuan Province,China

Abstract： Enhancing the efficiency of public services is essential to residents in mountainous areas. It is also important to promote sus- tainable development of these regions. Analysing residents＇ satisfaction with public services in mountainous areas can help in evaluating outcomes of fiscal investment and identifying potential coping approaches for improving public service efficiencies. The residents＇ satisfaction with public services and the factors that influence such satisfaction were examined in this study. A study of 12 towns located in the southwestern Sichuan Province was performed using an entropy-weighted analytic hierarchy process （EWAHP）, the technique for order preference by similarity to ideal solution （TOPSIS） and Tobit regression methods. The results indicate that： 1） the spatial distribu- tion of satisfaction with public services is non-uniform, and the spatial distribution structure varies for different types of public services. 2） Residents＇ satisfaction with public services is influenced by both objective and subjective factors. Population density, economic dis- tance, social and cultural divisions and elevation are the major objective factors, whereas bounded rationality, the hierarchy of needs and service expectations are the main subjective factors. The most effective strategies for enhancing residents＇ satisfaction with public ser- vices are likely to be clustering the population, choosing supply centres with different public services, regulating the cultural division in ethnic minority towns, selecting supply priorities in accordance with residents＇ needs, implementing targeted intervention policies and establishing ＇bottom-up＇ and ＇top-down＇ integrated decision-making mechanisms. Keywords： mountainous areas; public services; residents＇ satisfaction; entropy-weighted analytic hierarchy process （EWAHP）; technique for order preference by similarity to ideal solution （TOPSIS）; Tobit regression; southwestern Sichuan Province