6Baker EL, O'Neil HF.Measuring Problem Solving in Computer Environments: Current and Future States [J].Computers in Human Behavior,2002, (18) :609-622.
7Bigdeli A,Boys J,Coghill C. "OASIS-F":Development of a Fuzzy Online Assessment System [A].Proceedings of the 6th CAA Conference[C].http://www.caaconference.co.uk/pastConferences/2002/proceedings/index.asp,2002.
5Gibbon, Dafydd, IngeMertins&RogerK. Moore. Handbook of Multimodal and Spoken Dialogue Systems[ M ]. Boston : Kluwer Academic Publishers ,2000.
6P' erez D, Alfonseca, E, Rodr' lguez P. Application of the BLEU method for evaluating free text answers in an e- learning environment[C]//[s, n. ]. Proceedings of the lan- guage resources and evaluation conference (LREC-2004). Portugal: Lisbon, 2004.
7Mihalcea R, Corley C, Strapparava C. Corpus-based and knowledge-based measures of text semantic similarity. [C]//[s. n. ]. Proceedings of the American association for artificial intelligence (AAAI 2006). USA: Washington, 2OO6.
8Papineni K,Roukos S,Ward T,et al. BLEU: a method for automatic evaluation of machine translation. [C]//[s. n. ]. Proceedings of the 40th annual meeting of the association for computational linguistics (ACL 2002). USA: Philadel- phia,2002.
9Noorbehbahani F, Kardan A A. The automatic assessment of free text answers using a modified BLEU algorithm[J]. Computers & Education,2011,56(7): 337-345.
10He Y, Hui S H, Quan T T. Automatic summary assess ment for intelligent tutoring systems[J]. Computers & Ed- ucation,2009,53(3) : 890-899.