Clustering ensemble selection has shown high efficiency in the improvement of the quality of clustering solutions. This technique comprises two important metrics: diversity and quality. It has been empirically proved that ensembles of higher effectiveness can be achieved through taking into consideration the diversity and quality simultaneously. However, the relationships between these two metrics in base clusterings have remained uncertain. This paper suggests a new hierarchical selection algorithm using a diversity/quality measure based on the jaccard similarity measure. In the proposed algorithm, the selection of the subsets of the clustering partitions is done based on their diversity measures. The proposed diversity measure (in two types of pair-wise diversity and hybrid diversity) is applied to the proposed algorithm. Hypergraph-Partitioning Algorithm (HGPA), Cluster-based Similarity Partition Algorithm (CSPA), and Meta-CLustering Algorithm (MCLA) were used to obtain the consensus solution and cluster ensemble selection results with a hierarchical method. The experimental results on 14 datasets showed that selecting a subset of base clusterings using the proposed algorithm led to more accurate results compared to those of the full ensemble. The effectiveness and robustness of the proposed algorithm were demonstrated in comparison with the full ensemble. The comparative results showed that the proposed method by new diversity measure outperformed the full ensemble.

Owing to the special stance of prioritizing tasks in requirements engineering processes, and as the requirements are not independent in nature, considering their dependencies is essential during the prioritizing process. Although different classifications of dependency types among requirements exist, only a few approaches in the prioritization process consider such valuable data (dependency among requirements). To achieve a practical prioritization, this study proposes a method based on the effects of the requirement dependencies (increase/decrease cost of) on the value of prioritization provided by the tensor concept. Since the strengths of dependencies are also influential factors in the act of prioritization, the algebraic structure of fuzzy graphs is used to model the requirement dependencies and their strengths. Moreover, a weighted page rank algorithm based on the fuzzy concept is provided to determine the final dependency strength of the dependent requirements of the fuzzy graph. To evaluate the proposed approach, a controlled experiment is also conducted. The proposed approach is compared with an analytic hierarchy process-based approach, TOPSIS, and EVOLVE in the experiment. The results analysis demonstrates that our approach is less time-consuming, much easier to use, and highly accurate.