这是一篇关于半监督的论文，半监督学习问题广泛存在于现实世界中, 已经成为目前机器学习和模式识别领域中的一个研究热点. 文章

综述了半监督学习问题的基本思想、研究现状、常用算法及其一些应用领域, 分析了目前存在的主要困难, 并指出需进一步研究的几个问题.-Sem-i supervised learning has been w idely used in the w orld and become a hot topic in the resear ch

field of machine learning and pattern recog nit ion. T he paper summarizes the basic assumption, the resear ch

situat ion at present , and the alg orithms w hich w as used to reso lve some pract ical pro blems. Main dif f icu-l

t ies and the questio ns w hich w ill be solved in the future are also show n.