从信息检索到搜索引擎

信息检索是研究对大规模信息进行快速准确全面的获取、组织、挖掘和提供访问的一门学科，它的目标是从大规模文档集合中返回满足用户需求的文档子集。信息检索涉及自然语言处理、机器学习、数据挖掘、并行分布式处理等多个领域的相关技术。搜索引擎是信息检索的一个具有代表性的应用，也是目前互联网中最重要的应用之一。搜索引擎特别是Web搜索引擎在与一般信息检索系统拥有诸多共性的同时，也具有自己的特点。本文主要介绍信息检索这门学科的一般知识，然后以搜索引擎为例介绍信息检索技术的应用。

From Information Retrieval to Search Engine

Information Retrieval （IR） is a discipline that focuses on fast, accurate and cornprehensive information acquirement, organization, mining and application. The goal is to retrieve a document subset from large scale documents. IR closely interacts with other fields such as natural language processing, machine learning, data mining and parallel distributed processing. Search engine is a typical and popular IR system, which has its own characteristics while sharing general features with a common IR system. This paper gives a brief introduction of IR technologies and their applications in a search engine system.