資訊檢索的策略與的技巧.ppt

資訊檢索策略與技巧 黃慕萱，Chap.6 Harter，Chap. 7 檢索策略v.s.檢索技巧 最早為軍方用語 各家看法 1979，Marcia Bates，”Information Search Tactics” Hartly 如何避免找到不相關文章的方法 處理找到過多或過少相關文章的可能對策 Palmer 指分區組合檢索和引用文獻滾雪球法 Pao 指布林邏輯、引用文獻及機率檢索策略 檢索策略(search strategy) 針對一檢索問題之通盤考量或全面性之規劃 如分區組合檢索法、引用文獻滾雪球法….等 檢索技巧(search heuristics) 為完成特定目的所採取的行動 Briefsearch簡易檢索 最常見的檢索方式 快速簡單?fast and inexpensive 但常是低recall，低precision 適用 主題明確 想瞭解資料庫製作者所使用的敘述語和索引詞彙 確認書目資料 已知書名、作者等 Building Blocks Search分區組合檢索法 亦有人稱為“block building”或“building block” 檢索方式 將索引問題分解成數個主題層面(facets) 確定主題層面間的關係 通常facets間的關係為”AND”，出現”OR”或”NOT”的情況較少 找出可代表各主題層面的檢索詞彙 利用布林邏輯”OR”做聯集，以求完整性 使用率最高，早期參考晤談表格常依此設計 Building Blocks Search Strategy--1/4 Conduct reference interviews Formulate search objectives High recall High precision Moderate levels of recall and precision Select database(s) and search system Identify major concepts or facets and their logical relationships with one another Building Blocks Search Strategy--2/4 Identify search strings that represent the concepts Words Full-text phrases Pieces of words Descriptors Identifiers Codes Non-semantic bibliographic characteristics 非主題相關的欄位，如資料類型、語言、年代等 包括同義詞、類同義詞、狹義詞、相關詞 fields to be searched Building Blocks Search Strategy--3/4 For each distinct facet of the search, a set of postings will be created for each search string within that facet. The sets are then combined into a single set representing that facet using Boolean OR Following setp#6, the facets sets themselves will be combined with Boolean AND and NOT Plan alternatives Building Blocks Search Strategy--4/4 Formulate the initial statements of the search in the command language of the system Logon and put the search to the system Evaluate the intermediate results Iterate Use the interactive features of the system to carry out search heuristics ? tactics, maneuvers, strategies, tricks, devices, approaches, to try to improve search results Building blocks approach Building Blocks search sample 檢討結果重新檢索 想增加recall時 find additional concepts or search terms t