IC-kmedoids: a clustering algorithm for RNA secondary structure prediction / 生物医学工程学杂志

Due to the minimum free energy model, it is very important to predict the RNA secondary structure accurately and efficiently from the suboptimal foldings. Using clustering techniques in analyzing the suboptimal structures could effectively improve the prediction accuracy. An improved k-medoids cluster method is proposed to make this a better accuracy with the RBP score and the incremental candidate set of medoids matrix in this paper. The algorithm optimizes initial medoids through an expanding medoids candidate sets gradually. The predicted results indicated this algorithm could get a higher value of CH and significantly shorten the time for calculating clustering RNA folding structures.

Application of improved locally linear embedding algorithm in dimensionality reduction of cancer gene expression data / 生物医学工程学杂志

Cancer gene expression data have the characteristics of high dimensionalities and small samples so it is necessary to perform dimensionality reduction of the data. Traditional linear dimensionality reduction approaches can not find the nonlinear relationship between the data points. In addition, they have bad dimensionality reduction results. Therefore a multiple weights locally linear embedding (LLE) algorithm with improved distance is introduced to perform dimensionality reduction in this study. We adopted an improved distance to calculate the neighbor of each data point in this algorithm, and then we introduced multiple sets of linearly independent local weight vectors for each neighbor, and obtained the embedding results in the low-dimensional space of the high-dimensional data by minimizing the reconstruction error. Experimental result showed that the multiple weights LLE algorithm with improved distance had good dimensionality reduction functions of the cancer gene expression data.

MicroRNA target predicition based on SVM and the optimized feature set / 生物医学工程学杂志

MicroRNA (miRNA) is a family of endogenous single-stranded RNA about 22 nucleotides in length. Through targeting 3' UTR of message RNA (mRNA), they play important roles in post-transcriptional regulatory functions. For further research of miRNA function, the identification of more miRNA positive targets is needed urgently. Aiming at the high-dimensional small sample data sets in miRNA target prediction, an algorithm of eliminating redundant features is proposed based on v-SVM in this paper, and classification and features selection are also fused. The algorithm of eliminating redundant features optimizes the combination of features, and then constructs the best features combination which can represent miRNA and targets interaction model. The prior parameter v (0 < u < or = 1) controls the compression proportion of data set and selects more distinguishing support vectors. Finally, the classifier model of miRNA target prediction is built. The unbiased assessment of the classifier is achieved with a completely independent test dataset. Experiment results indicated that in both classification recognition and generalization performance of miRNA targets predicition, this model was superior to the present machine learning algorithms such as miTarget, NBmiRTar and TargetMiner, etc.