Fast structural query with application to chinese treebank sentence retrieval

Abstract

In natural language processing, a huge amount of structured data is constantly used for the extraction and presentation of grammatical structures in sentences. For example, the Chinese Treebank corpus developed at the Institute of Information Science, Academia Sinica, Taiwan, is a semantically annotated corpus that has been used to help parse and study Chinese sentences. In this setting, users usually use structured tree patterns, instead of keywords, to query the corpus.In this paper, we present an online prototype system that provides exploratory search ability. The system implements two flexible and efficient structural query methods and employs a user-friendly web-based interface. Although the system adopts the XML format to present the corpora and search results, it does not use conventional XML query languages. As searching the Chinese Treebank corpora is structural in nature and often deals with structural similarities, conventional XML query languages, such as XPath and XQuery, are inflexible and inefficient. We propose and implement a query algorithm, called Parent-Child Relationship Filter (PCRF), which provides flexible and efficient structural search. PCRF is sufficiently flexible to provide several similarity-matching options, such as wildcard, unordered sibling, sub-trees, ancestor-descendant matching, and their combinations. In addition, PCRF supports stream-based matching to help users query XML documents online. We also present three accelerating rules that achieve a 1.5-to 8-fold performance improvement in query time. Our experiment results show that our method archive a 10-to 1000-fold performance improvement compared to the usual text-based XPath query method.

Prefiltering techniques for efficient XML document processing

“…Rather than developing another structural query evaluation algorithm to deal with structural queries, we slightly modify the Parent-Child Relationship Filter (PCRF) algorithm developed in our previous work [4] and apply it to FLISA. The design methodology of PCRF is to filter out ineligible candidate fragments from the XML document as soon as possible, and not to spend time evaluating them.…”

“…To show that our prefiltering framework is practical, we apply it to two existing applications, a Chinese sentence search engine [4] and an XML-based GIS system [5]. We introduce them briefly in the following sections.…”

“…In our previous work [4], we designed a fast structural query algorithm, the Parent-Child Relationship Filter (PCRF) algorithm for querying as well as analyzing the CKIP Chinese Treebank corpus [12]. Taking the advantages provided by a RDBMS, PCRF is able to attain outstanding performance.…”

“…Many indexing techniques, such as structural summaries [16] [17], path indexes [14], and edge indexes [4], have been proposed for improving XML query efficiency. In our previous work [4], we used a tree-to-table mapping and the robust indexing techniques provided by relational database management system (RDBMS) to help answer structural queries to large, or large collections of, XML documents efficiently. However, almost all of the above schemes rely on expensive indexing schemes or external data storage systems that are unavailable in small-scale applications.…”

“…To the best of our knowledge, enabling a streaming parser to provide random access ability has not been proposed and implemented until now. By using our enhanced streaming parser, the response times of two existing applications, one being a Chinese Treebank search engine [4], and the other one a geographic information systems (GIS) maps rendering system [5], have been greatly reduced. These experiment results will be shown in this paper.…”