个人总结及展望.ppt

  1. 1、本文档共26页,可阅读全部内容。
  2. 2、有哪些信誉好的足球投注网站(book118)网站文档一经付费(服务费),不意味着购买了该文档的版权,仅供个人/单位学习、研究之用,不得用于商业用途,未经授权,严禁复制、发行、汇编、翻译或者网络传播等,侵权必究。
  3. 3、本站所有内容均由合作方或网友上传,本站不对文档的完整性、权威性及其观点立场正确性做任何保证或承诺!文档内容仅供研究参考,付费前请自行鉴别。如您付费,意味着您自己接受本站规则且自行承担风险,本站不退款、不进行额外附加服务;查看《如何避免下载的几个坑》。如果您已付费下载过本站文档,您可以点击 这里二次下载
  4. 4、如文档侵犯商业秘密、侵犯著作权、侵犯人身权等,请点击“版权申诉”(推荐),也可以打举报电话:400-050-0827(电话支持时间:9:00-18:30)。
查看更多
我做的工作就是简单的分类,利用已经有的样例训练出一个模型,然后根据模型来分类未知的数据。这个工作中主要的创新点就是使用集成分类器去预测,可以大大提高预测的准确性,而且使用RNAfold特征提取方法,大大减少了时间耗费。 * 下面介绍miRFam使用n-gram的特征提取方法 由于miRNA只有四个碱基,miRFam使用4个唯一的unigram,42个唯一的bigram,43个唯一的trigram,一共有4+42+43 =84个特征( A,C,G,U,AA,AC,AG,AU,CA,CC,CG,CU……) miRFam使用集中系数的概念来把这些不同的特征整合成一个特征向量,首先,定义类型i的唯一n-gram的数量用Ni表示,类型i的集中系数就是: Ci =Ni/∑3j=1Nj , i=1,2,3 当然我么可以得到: C1=4/4+16+64=0.048 C2=16/4+16+64=0.190 C3=64/4+16+64=0.762 然后特征向量可以通过下面的公式计算: fj = tj/Ti*Ci, 1=j=84 其中,tj是某一种类型i的唯一的n-gram的出现频率,Ti是类型i的所有的唯一n-gram的出现频率。特征向量包含84维,每一维对应于某一种类型i (i =1,2,3,4)的一种n-gram。 * The three layers prediction method was mentioned. The 1st layer: 19 families with the largest members are selected and each of them respectively is viewed as a?class, a total of?19 classes,?remaining?as?the last class,?the?prediction change into?a new model that the?number of the target?class has only?20?classes (the dataset is denoted as and the random forest model is noted as RF1). For the 2nd layer, we?select?the?top?99?families, respectively.?Each of them is seen as a class,?and the residual?ones are taken as?a?class. So there are total of?100?classes (the dataset is denoted as , and the random forest model is noted as RF2). For the 3rd layer, we classify the miRNA families as same as miRBase (the dataset is denoted as the random forest model is noted as RF3). Our method can identify families hierarchically and judge whether a novel miRNA belongs to the popular families. The complete forecasting process is shown in Figure 2. The predicted sequence starts from the 1st layer, and if it is predicted as one of the top 19 families, the output is considered as the last result and the process will finish. Otherwise the process will automatically continue to the 2nd layer prediction. The sequence will be predicted whether it belongs to the top 99 families. If it doesnt belong to yet, miRClassify will go into the 3rd layer and the 3rd layer predictor will give the last result. Hierarchical predictors are used in

文档评论(0)

magui + 关注
实名认证
内容提供者

该用户很懒,什么也没介绍

版权声明书
用户编号:8140007116000003

1亿VIP精品文档

相关文档