Development of a Full Text Retrieval System based on Logical Structure of Documents

调查人员已经进行了一个系统的研究和开发，用户可以从包含学术论文等完整文件的全文数据库中检索文件。主要研究结果如下：1.在详细分析全文数据库检索请求的基础上，根据SGML的文档类型定义，详细设计了一种有效描述检索和显示请求的形式化表示法DQL（Document Query Language）。2.他们设计了一个用户系统软件，它显示文档结构，让用户用定点设备选择元素，指定检索条件和显示指令。该系统是在工作站上使用图形用户界面系统开发的。3.他们在一台主机上开发了一个服务器系统软件，该软件通过将结构表示为元素之间的二项式关系并处理DQL中描述的检索请求，将文档存储在关系数据库管理系统中。4.他们开发了服务器和用户系统之间的通信方法，并通过使用LAN和ISDN的实验验证了功能。5.他们对服务器系统的整体性能、可用性、检索精度等进行了评估，并针对实际使用中存在的问题和解决方案进行了思考，通过评估，揭示了服务器系统性能改进的必要性。进一步的研究表明，在二项式关系记录中包含引用的记录标识符是有效的。实现这种方法是未来的问题。用户系统表示指定的检索请求更容易理解的必要性也被揭示出来。通过实验研究，验证了系统设计思想和实现方法的可行性，提出了解决问题的方法，展示了系统的实用性。

The investigators have conducted research and development of a system with which users can retrieve documents from a full text database containing full documents such as academic papers. Results obtained were as follows: 1. Based on detailed analysis of retrieval requests for full text databases, they made detailed design of a formal notation DQL (Document Query Language) for describing retrieval and display requests efficiently according to the document type definition of SGML. 2. They designed a user system software which displays document structures and let users select elements with pointing devices and specify retrieval conditions and display instructions. The system w as developed on work-stations using graphical user interface systems. 3. They developed a server system software on a main frame computer which stores documents in a relational database management system by expressing the structure as binomial relations among elements and processes retrieval requests described in DQL. 4. They developed a communication method between sever and user systems and confirmed the functionality by experiments using LAN and ISDN. 5. They evaluated the overall performance, usability, retrieval precision and so on and considered on the problems and their solutions toward the practical use.Through evaluation, the necessity of performance improvement of the server system was revealed. Further investigation has made it clear that including referenced record identifiers within the binomial relation records is effective. It is the future issue to implement this method. The necessity for the user system to represent specified retrieval requests more understandably was also revealed. Several methods already proposed should be studied by experiments.As the result of the research, feasibility of the design concept and the implementation method of this system was confirmed, the approach to the existing problems was presented, and the reality of the full-fledged system was shown.