12 2009 档案

摘要：Here are some things to try to speed up the seaching speed of your Lucene application. Please see ImproveIndexingSpeed for how to speed up indexing.以下是一些尝试提高lucene程序检索速度的方法. 如果需要提高索引速度,请看提高索引速度.Be sure you really need to speed things up. Many of the ideas here are simple to try, but others will nece 阅读全文

摘要：相信很多学习向量空间模型(Vector Space Model)的人都会被其中的余弦定理公式所迷惑..因为一看到余弦定理,肯定会先想起初中时的那条最简单的公式cosA=a/c(邻边比斜边),见下图:但是,初中那条公式是只适用于直角三角形的,而在非直角三角形中,余弦定理的公式是:cosA=(c2 + b2 - a2)/2bc不过这条公式也和向量空间模型中的余弦定理公式不沾边,迷惑..引用吴军老师的数... 阅读全文

摘要：Vector space model (or term vector model) is an algebraic model for representing text documents (and any objects, in general) as vectors of identifiers, such as, for example, index terms. It is used i... 阅读全文

摘要：第一次用apache.commons.dbutils.QueryRunner访问数据库的人会有一个疑问..String url = "jdbc:mysql://localhost:3306/test";Connection con = DriverManager.getConnection(url, "root", "pwd");String sql = "select * from myTable";QueryRunner qr = new QueryRunner();qr.query(con, sql, han 阅读全文