ABSTRACT
The vertical search engine is also called industry search engine, or professional search engine, it is oriented for the professional industry field, for the professional searching the content of the particular industry, with specific nature and targeted. With the development and expansion of the Internet, the network forms and data have undergone tremendous changes, especially the development of access method into the Internet in recent years, handheld devices greatly increased, with big data of network coming, the network search engine developed from the general search engine into the vertical search engine that adapts to a variety of professional requirements. No matter what kind of search, premise is to convert the data from unstructured to structured, then put the network data into the database that designed early; for the vertical search, extraction of professional information data is the most important part of the work in the process of data structure. Professional information data build the professional information named entity database, it is the structured data information database, contains a field data information collection. For example, filed product classification named entity library, enterprise product named entity library, city real estate named entity library, public bus named entity library, a person of ability post classification named entity library etc. Construction of the professional information named entity corpus is often by Manual Defragmentation is complete, in practical application, only manually collecting is very difficult, the workload is huge, especially the update speed, it often fails to complete the work [1].
