%0 Journal Article
%T Graph traversal and top-down evaluation of logic queries<br>Graph Traversal and Top-Down Evaluation of Logic Queries
%A Chen Yangjun
%A <br>Chen
%A Yangjun
%J 计算机科学技术学报
%D 1998
%I 
%X In this paper, an optimal method to handle cyclic and acyclic data relations in the linear recursive queries is proposed. High efficiency is achieved by integrating graph traversal mechanisms into a top-down evaluation. In such a way the subsumption checks and the identification of cyclic data can be done very efficielltly First, based on the subsumption checks, the search space can be reduced drastically by avoiding any redundant expansion operation. In fact, in the case of non-cyclic data, the proposed algorithm requires only linear time for evaluating a linear recursive query. On the other hand, in the case of cyclic data, by using the technique for isolating strongly connected components a lot of answers can be generated directly in terms of the intermediate results and the relevant path information instead of evaluating them by performing algebraic operations. Since the cost of generating an answer is much less than that of evaluating an answer by algebraic operations, the time consumption for cyclic data can be reduced by an order of magnitude or more.
%K recursive query
%K top-down evaluation
%K RQA/FQI strategy
%K logic query
%K graph traversal<br>人工智能
%K 递归询问
%K 逻辑询问
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=5B3AB970F71A803DEACDC0559115BFCF0A068CD97DD29835&cid=8240383F08CE46C8B05036380D75B607&jid=F57FEF5FAEE544283F43708D560ABF1B&aid=823F7DD829603068AB506BBFC9B00A6E&yid=8CAA3A429E3EA654&vid=FC0714F8D2EB605D&iid=E158A972A605785F&sid=B1E36BF7B9783A85&eid=EC34D52BE81085CE&journal_id=1000-9000&journal_name=计算机科学技术学报&referenced_num=0&reference_num=22