Web Search Overview Crawling IR Big Issues in IR Users and Information Needs Search evaluation is user-centered Keyword queries are often poor descriptions of actual information needs Interaction and context are important for understanding user intent Query refinement techniques such as query expansion, query suggestion, relevance feedback improve ranking 16
Web Search Overview & Crawling 16 Big Issues in IR ▪ Users and Information Needs ▪ Search evaluation is user-centered ▪ Keyword queries are often poor descriptions of actual information needs ▪ Interaction and context are important for understanding user intent ▪ Query refinement techniques such as query expansion, query suggestion, relevance feedback improve ranking IR
Web Search Overview Crawling IR IR and Search Engines A search engine is the practical application of information retrieval techniques to large scale text collections Web search engines are best-known examples, but many others Open source search engines are important for research and development e.g., Lucene, Lemur/Indri, Galago Big issues include main IR issues but also some others 17
Web Search Overview & Crawling 17 IR and Search Engines ▪ A search engine is the practical application of information retrieval techniques to large scale text collections ▪ Web search engines are best-known examples, but many others ▪ Open source search engines are important for research and development ▪ e.g., Lucene, Lemur/Indri, Galago ▪ Big issues include main IR issues but also some others IR