Natural language

圖書館的「線上公用目錄」（On-Line Public Access Catalog, OPAC）系統，是提供讀者查詢圖書館館藏資料的重要工具，也是早期資訊檢索技術主要的應用方向。本文即以輔仁大學圖書館為例，說明整合新一代資訊檢索技術於 OPAC 系統的實施現況。我們運用非營利機構可獲得的先進檢索引擎，輔以自行發展的關鍵詞擷取技術，完成具備重要性排序、近似字串、模糊搜尋、相關詞回饋、允許近似自然語言檢索字串的 OPAC 系統。初步的評估發現，這樣的系統對協助使用者簡化查詢條件、拓展檢索字彙、提昇檢索成效有相當的助益。

The On-Line Public Access Catalog (OPAC) system is an important tool in helping users to retrieve information from a large volume of data stored in a library. However, recent advances in information retrieval technologies have not yet been applied to most OPAC systems. This paper introduces the development of a novel OPAC system which applies a free advanced search engine available from the Internet and an automatic keyword extraction function developed by the Department of Library and Information Science. The resultant features of the OPAC system include relevance ranking, fuzzy search, relevance feedback, and query by quasi-natural language. Results show that such a system greatly simplifies query formulations and automatically prompts more relevant search vocabulary to the users, thus improving the performance of an OPAC system to a higher degree.

資訊檢索研究的目的在解決人類對於資訊的需求，發展至今不斷地消除一道道的資訊藩籬。隨著電腦網路的普及，網際網路快速地深入世界的每一個角落，普羅大眾對於「世界村」觀念感同身受的同時，語言的藩籬變得具體而殘酷，使用者很難檢索「不同文」的文獻資料。本文說明資訊檢索的語言藩籬，討論目前語言技術用於處理語言藩籬的可能方案，並且比較現有超越語言藩籬的資訊檢索系統與傳統資訊檢索系統之間的系統績效。

The purpose of research for information retrieval (IR) is to fulfill information need. IR has eradicated many information barriers from the very beginning. With the fast development of computer networks, the Internet has turned the world into a global village. But when the Internet users try to locate documents in different language, the once implicit language barrier becomes real and crucial. This paper attempts to explore the language barrier underlying the process of information retrieval, the possible solutions of this barrier, and a comparison of the performance of cross-language information retrieval and monolingual information retrieval systems.