• 中国计算机学会会刊
  • 中国科技核心期刊
  • 中文核心期刊

J4 ›› 2011, Vol. 33 ›› Issue (12): 148-152.

• 论文 • 上一篇    下一篇

改进LPU用于蛋白质功能预测

陈义明1,2,李舟军1,刘军万1   

  1. (1.国防科学技术大学计算机学院,湖南 长沙 410073;2.湖南农业大学信息科学技术学院,湖南 长沙 410128)
  • 收稿日期:2009-09-07 修回日期:2009-12-15 出版日期:2011-12-24 发布日期:2011-11-25

CHEN Yiming1,2,LI Zhoujun1,LIU Junwan1   

  1. (1.School of Computer Science,National University of Defense and Technology,Changsha 410073;2.School of Information Science and Technology,Hunan Agricultural University,Changsha 410128,China)
  • Received:2009-09-07 Revised:2009-12-15 Online:2011-12-24 Published:2011-11-25

摘要:

本文将蛋白质功能预测定义为典型的LPU问题。针对有很少正例的LPU算法存在的不平衡或过拟合问题,提出了基于最近邻和凸组合理论的创建人工正例扩充正例集合的方法,同时使用一类支持向量机获取初始最可能的负例,通过迭代两类支持向量机将分类超平面移到一个合适的位置,由交叉验证获得代表性的负例,从而改进了典型LPU算法学习最优分类器的过程。针对酵母基因组数据的实验表明:我们的算法在很少正例的功能类上的预测性能有显著提高,在其他类上的性能也有一定的改善。

关键词: 蛋白质功能预测, 支持向量机, LPU

Abstract:

This paper formulates the protein function prediction into a typical LPU. Aiming at imbalance or overfitting from LPU with few positive examples, it proposes a method creating synthetic examples to enlarge the set of positive examples based on the nearest neighbor and convex combination, and meanwhile modifies the procedure learning optimal classifier for the classic LPU algorithm by using oneclass SVM(support vector machine) to identify the most probable negative examples, running iteratively SVM to move the classification hyperplane to a suitable place and obtaining representative negative examples through cross validation. For the yeast genomic data, the experiments show that our algorithm outperforms several classic prediction methods, particularly, for function classes with few positive examples.

Key words: protein function prediction;SVM;LPU