【摘要】 网上信息资源不断变化 ,搜索引擎需要不断更新它所访问过的网页 ,提高更新效率是搜索引擎的关键技术所在 .在总结搜索引擎现有页面更新技术的基础上 ,对两种不同的页面更新策略 (统一更新策略和个体更新策略 )进行了比较 ,指出了两种方案的优劣所在 ,进而提出了一种改进的折衷方案即分类更新策略 ,并从理论上论证了其优越性 ,在实际应用中评价了其有效性 ,结果表明分类更新策略很大程度上改进了搜索效果更多还原

【Abstract】 This paper described the basic principle of search engine. On the basis of the present technologies of Web freshness, the uniform freshness strategy and the personal freshness strategy were compared and the advantages and disadvantages of their strategies were put forward. The paper presented an advanced scheme, classified freshness strategy with a demonstration of its optimization in theory and its efficiency in practice. The results showed that the classified freshness strategy improved the searching effect obviously.更多还原