A Review of Question Answering Systems


  • Bolanle Ojokoh Department of Information Systems, Federal University of Technology, Akure, Nigeria
  • Emmanuel Adebisi Department of Computer Science, Federal University of Technology, Akure, Nigeria


Question Analysis, Answer Extraction, Information Retrieval, Classification, Review


Question Answering (QA) targets answering questions defined in natural language. Question Answering Systems offer an automated approach to procuring solutions to queries expressed in natural language. A lot of QA surveys have classified Question Answering systems based on different criteria such as queries inquired by users, features of data bases used, nature of generated answers, question answering approaches and techniques. To fully understand QA systems, how it has grown into its current QA needs, and the need to scale up to meet future expectations, a broader survey of QA systems becomes essential. Hence, in this paper, we take a short study of the generic QA framework vis a vis Question Analysis, Passage Retrieval and Answer Extraction and some important issues associated with QA systems. These issues include Question Processing, Question Classes, Data Sources for QA, Context and QA, Answer Extraction, Real time Question Answering, Answer Formulation, Multilingual (or cross-lingual) question answering, Advanced reasoning for QA, Interactive QA, User profiling for QA and Information clustering for QA. Finally, we classify QA systems based on some identified criteria in literature. These include Application domain, Question type, Data source, Form of answer generated, Language paradigm and Approaches. We subsequently made an informed judgment of the basis for each classification criterion through literature on QA systems.


Download data is not yet available.

Author Biographies

Bolanle Ojokoh, Department of Information Systems, Federal University of Technology, Akure, Nigeria

Bolanle Ojokoh holds B.Sc, M.Tech and Ph.D degrees in Computer Science. She is currently an Associate Professor in Information Systems of the Federal University of Technology, Akure (FUTA), Nigeria. She is a member of some professional bodies including Organization of Women in Science for the Developing World (OWSD) and Association of Computing Machinery (ACM). She has mentored more than ten Masters theses to completion and is currently supervising some Masters and Ph.D students. Her current research interests include Question Answering, Information Retrieval, Filtering and Extraction, Recommender Systems, and Gender issues in Science and Information Technology. She was awarded TWAS Young Affiliate in July 2013 and is currently and an Executive Board Member of the TWAS Young Affiliate Network (TYAN).

Emmanuel Adebisi, Department of Computer Science, Federal University of Technology, Akure, Nigeria

Emmanuel Adebisi is a Ph.D. student at the Federal University of Technology, Akure since March 2019. He attended Joseph Ayo Babalola University, Osun state Nigeria where he received his B.Sc. in Computer Science in 2014. Emmanuel obtained his M.Tech. in Computer Science from Federal University of Technology, Akure Ondo state, Nigeria in 2018. Emmanuel is a software developer and works as a consultant to IT Firms. He is also the C.E.O of Techatrek (a tech company he started in 2014). He worked as a Teaching Assistant at Federal College of Education (Special) Oyo (2014–2015) and Federal University of Technology Akure from (2016–2018). His Ph.D. work centers on Automatic Question Answering Systems.


Agichtein, E., and Savenkov, D. 2016. CRQA: Crowd-Powered Real-Time Automatic Question Answering System. HCOMP.

Ahmed, W., and Babu, P. A. 2016. Answer Extraction and Passage Retrieval for Question Answering Systems. ISSN:2278-1323 International Journal of Advanced Research in Computer Engineering and Technology (IJARCET), 5(12).

Androutsopoulos, I., Ritchie, G. D., and Thanisch, P. 1993. MASQUE/SQL – an efficient and portable natural language query interface for relational databases, In: Proc. of the 6th International Conference on Industrial and Engineering Applications of Artificial Intelligence and Expert Systems, Gordon and Breach Publisher Inc., Edinburgh, pp. 327–30.

Attardi, G., Cisternino, A., Formica, F., Simi, M., and Tommasi, A. 2001. PiQAS: Pisa Question Answering System. TREC.

Banerjee, S., and Bandyopadhyay, S. 2012. Bengali Question Classification: Towards Developing QA System. In: Proceedings of the 3rd Workshop on South and Southeast Asian Natural Language Processing (SANLP), pp. 25–40, COLING 2012, Mumbai.

Basic, B. D., Lombarovic, T., and Snajder, J. 2011. Question Classification for a Croatian QA System. In: Habernal I., Matousek V. (eds) Text, Speech and Dialogue. TSD 2011. Lecture Notes in Computer Science, 6836. Springer, Berlin, Heidelberg.

Baudiš, P., and Šedivy, J. 2015. Modeling of the Question Answering’ task in the YodaQA system. In Proceedings, Lecture Notes in Computer Science, 9283, Springer, pp. 222–8.

Benamara, F. 2004. Cooperative question answering in restricted domains: the WEBCOOP experiments, In: In Workshop on Question Answering in Restricted Domains, 42nd Annual Meeting of the Association for Computational Linguistics, Barcelona, Spain, pp. 31–8.

Benamara, F., and Kaci, S. 2006. Preference Reasoning in Advanced Question Answering Systems, In: A. Sattar, B. Kang (eds) Advances in Artificial Intelligence, AI 2006, Lecture Notes in Computer Science, vol. 4304, Springer, Berlin, Heidelberg.

Berger, A., Caruana, R., Cohn, D., Freitag, D., and Mittal, V. 2000. Bridging the lexical chasm: statistical approaches to answer-finding, In Proceedings of the 23rd annual international ACM SIGIR conference on Research and development in information retrieval, pp. 192–99.

Bergeron, J., Schmidt, A., Khoury, R., and Lamontagne, L. 2016. Building User Interest Profiles Using DBpedia in a Question Answering System. AAAI Publications, The Twenty-Ninth International Flairs Conference.

Bharat, V. K., Vilas, D. P., Uddav, D. S., and Sugriv, D. V. 2016. Multimedia Question Answering System. International Journal of Engineering and Techniques, 2(2).

Bhaskar, P., Banerjee, S., Pakray, P., Banerjee, S., Bandyopadhyay, S., and Gelbukh, A. 2013. A Hybrid Question Answering System for Multiple Choice Question (MCQ). QA4MRE@CLEF 2013.

Bhoir, V., and Potey, M. A. 2014. Question answering system: A heuristic approach. The Fifth International Conference on the Applications of Digital Information and Web Technologies (ICADIWT), pp. 165–70.

Biplab, C. D. 2014. A Survey on Question Answering System. Department of Computer Science and Engineering, Indian Institute of Technology, Bombay.

Bizer, C., Lehmann, J., Kobilarov, G., Auer, S., Becker, C., Cyganiak, R., and Hellmann, S. 2009. DBpedia-A crystallization point for the Web of Data. Web Semantics: science, services and agents on the world wide web, 7(3):154–65.

Bobrow, D. G., Kaplan, R. M., Kay, M., Norman, D. A., Thompson, H., and Winograd, T. 1977. GUS, a frame-driven dialog system. Artificial Intelligence, 8(2):155–73.

Bollacker, K., Evans, C., Paritosh, P., Sturge, T., and Taylor, J. 2008. Freebase: a collaboratively created graph database for structuring human knowledge, In SIGMOD, pp. 1247–50.

Bosma, W., Ghijsen, M., Johnson, W. L., Kole, S., Rizzo, P., and Welbergen, H. V. 2004. Generating Socially Appropriate Tutorial Dialog. ADS 2004, pp. 254–64.

Bouma, G. 2005. Linguistic Knowledge and Question Answering. In: Proceeding KRAQ ‘06 Proceedings of the Workshop KRAQ’06 on Knowledge and Reasoning for Language Processing. pp. 2–3.

Bouziane, A., Bouchiha, D., Doumi, N., and Malki, M. 2015. Question Answering Systems: Survey and Trends, Procedia Computer Science 73:366–75.

Brill, E., Lin, J., Banko, M., Dumais, S., and Ng, A. 2001. Data-intensive question answering, In TREC, pp. 393–400.

Burger, J., Cardie, C., Chaudhri, V., and Weischedel, R. 2001. Issues, task and program structure to roadmap research in question answering (QandA). https://www.researchgate.net/publication/228770683 Issues tasks and program structures to roadmap research in question answering QA.

Burke, R. D., Hammond, K. J., and Kulyukin, V. 1997. Question Answering from Frequently-Asked Question Files: Experiences with the FAQ Finder system. Tech. Rep. TR-97-05.

Cai, D., Dong, Y., Lv, D., Zhang, G., and Miao, X. 2005. A Web-based Chinese question answering with answer validation. In Proceedings of IEEE International Conference on Natural Language Processing and Knowledge Engineering, pp. 499–502.

Carbonell, J., Harman, D., and Hovy, E. 2000. Vision statement to guide research in question and answering (QandA) and text summarization. https://www-nlpir.nist.gov/projects/duc/papers/Final-Vision-Paper-v1a.ps

Chai, J. Y., and Jin, R. 2004. Discourse structure for context question answering. Department of Computer Science and Engineering Michigan State University East Lansing, MI 48864.

Chen, W., Zeng, Q., Wenyin, L., and Hao, T. 2007. A user reputation model for a user-interactive question answering system. Concurrency Computat.: Pract. Exper., pp. 2091–103.

CHUA, T. S., Hong, R., Li, G., and Tang, J. 2010. Multimedia Question Answering. Scholarpedia, 5(5):9546.

Chu-Carroll, J., and Fan, J. 2011. Leveraging Wikipedia characteristics for search and candidate generation in question answering, AAAI’11 Proceedings of the twenty-fifth AAAI conference on Artificial Intelligence, pp. 872–7.

Chu-Carroll, J., Ferrucci, D., Prager, J., and Welty, C. 2003. Hybridization in Question Answering Systems. From: AAAI Technical Report SS-03-07.

Chung, H., Song, Y. I., Han, K.S., Yoon, D.S., Lee, J.Y., and Rim, H.C. 2004. A Practical QA System in Restricted Domains. In Workshop on Question Answering in Restricted Domains, 42nd Annual Meeting of the Association for Computational Linguistics (ACL), pp. 39–45.

Clark, P., Thompson, J., and Porter, B. 1999. A knowledge-based approach to question answering, In Proceedings of AAAI’99 Fall Symposium on Question-Answering Systems, pp. 43–51.

Clarke, C., Cormack, G., and Lynam, T. 2001. Exploiting redundancy in question answering. In proceedings of the 24th SIGIR Conference, pp. 358–65.

Cui, H., Kan, M. Y., and Chua, T. S. 2007. Soft pattern matching models for definitional question answering. ACM Trans. Inf. Syst. (TOIS) 25(2).

Datla, V., Hasan, S.A., Liu, J., Lee, Y. B. K., Qadir, A., Prakash, A., and Farri, O. 2016. Open Domain Real-Time Question Answering Based on Semantic and Syntactic Question Similarity. Artificial intelligence laboratory, Philips research North America, Cambridge, MA, USA.

Dong, T., Furbach, U., Glockner, I., and Pelzer, B. 2016. A Natural Language Question Answering System as a Participant in Human QandA Portals. Published in: Proceeding IJCAI’11 Proceedings of the Twenty-Second international joint conference on Artificial Intelligence. Barcelona, Catalonia, Spain. 3:2430-5.

Dwivedi, S. K., and Singh, V. 2013. Research and reviews in question answering system. International Conference on Computational IntellIgence: Modeling Techniques and Applications CIMTA) Procedia Technology, pp. 417–24.

Echihabi, A., Hermjakob, U., Hovy, E., Marcu, D., Melz, E., and Ravichandran, D. 2008. How to Select Answer String?. In: Strzalkowski T., Harabagiu S.M. (eds) Advances in Open Domain Question Answering. Text, Speech and Language Technology, 32, Springer, Dordretch.

Fader, Zettlemoyer, L. S., and Etzioni, O. 2013. Paraphrase-driven learning for open Question Answering, In Proceedings of the 51st Annual Meeting of the Association for Computational Linguistics, ACL, pp. 4–9.

Fahmi. 2009. Automatic Term and Relation Extraction for Medical Question Answering System, PhD Thesis, University of Groningen, Netherlands, pp.13–4.

Fan, B., Xingwei, Z., and Hau, Y. 2010. Function based question classification for general QA, In: Proceedings of Conference on Empirical Methods in Natural Language Processing, MIT USA, pp. 1119–28.

Ferrucci, D., Brown, E., Chu-Carroll, J., Fan, J., Gondek, D., Kalyanpur, A.A., and Lally, A. 2010. Building Watson: An overview of the DeepQA project. AI magazine 31(3): 59–79.

Forner, P., Giampiccolo, D., Magnini, B., Peñas, A., Rodrigo, Á., and Sutcliffe, R. 2008. Evaluating Multilingual Question Answering Systems at CLEF.

Foster, G. F., and Plamondon, L. 2003. Quantum, a French/English Cross-Language Question Answering System. CLEF.

Fu, J., Jia, K., and Xu, J. 2009. Domain Ontology Based Automatic Question Answering, International Conference on Computer Engineering and Technology, pp. 346–349.

Giampiccolo, D., Forner, P., Herrera, J., Peñas, A., Ayache, C., Forascu, C., Jijkoun, V., Osenova, P., Rocha, P., Sacaleanu, B., and Sutcliffe, R. 2007. Overview of the CLEF 2007 Multilingual Question Answering Track, In: Peters, C., Jijkoun, V., Mandl, T., Müller, H., Oard, D. W., Peñas, A., and Santos, D. (Eds.), Advances in Multilingual and Multimodal Information Retrieval, 8th Workshop of the Cross-Language Evaluation Forum, CLEF, Revised Selected Papers.

Gliozzo, A. M., and Kalyanpur, A. 2012. Predicting Lexical Answer Types in Open Domain QA, Int. J. Semantic Web Inf. Syst., 8:74–88.

Goh, O. S., and Cemal, A. 2005. Response quality evaluation in heterogeneous question answering system: a black-box approach. World Academy of Sciences Engineering and Technology.

Green, B. F., Wolf, A. K., Chomsky, C., and Laughery, K. 1961. Baseball: An automatic question answerer. Readings in natural language processing. pp. 545–9. Morgan Kaufmann Publishers Inc.

Guda, V., Sanampudi, S. K., and Manikyamba, I. L. 2011. Approaches for question answering systems. International Journal of Engineering science and technology (IJEST), ISSN:0975-5462, 3(2).

Gunawardena, T., Lokuhetti, M., Pathirana, N., Ragel, R., and Deegalla, S. 2010. An automatic answering system with template matching for natural language questions. In Proceedings of 5th IEEE International Conference on Information and Automation for Sustainability (ICIAFs), pp. 353–8.

Hakimov, S., Tunc, H., Akimaliev, M., and Dogdu, E. 2013. Semantic Question Answering system over Linked Data using relational patterns, In Workshop Proceedings, New York, USA, pp. 83–8.

Hans, A. F., Feiyu, U. K., Uszkoreit, X. H., Brigitte, B. C., and Schäfer, J. U. 2006. Question answering from structured knowledge sources, German Research Center for Artificial Intelligence, DFKI.

Hao, X., Chang, X., and Liu, K. 2007. A Rule-based Chinese question Answering System for reading Comprehension Tests, In 3rd International Conference on International Information hiding and Multimedia Signal Processing, 2:325–9.

Harabagiu, S., Moldovan, D., Pasca, M., Mihalcea, R., Surdeanu, M., Bunescu, R., Girju, R., Rus, V., and Morarescu, P. 2001. The Role of Lexico-Semantic Feedback in Open-Domain Textual Question Answering. In Proceedings of ACL.

Herrera, J., Peñas, A., and Verdejo, F. 2005. Question Answering Pilot Task at CLEF 2004, Multilingual Information Access for Text, Speech and Images, 3491. Lecture Notes in Computer Science, pp. 581–90.

Higashinaka, R., and Isozaki, H. 2008. Corpus-based question answering for why-questions, In: Proceedings of the International Joint Conference on Natural Language Processing (IJCNLP), pp. 418–25.

Hirschman, L., and Gaizauskas, R. 2001. Natural Language Engineering Cambridge University Press. http://start.csail.mit.edu/index.php.

Hoffner, K., Walter, S., Marx, E., Usbeck, R., Lehmann, J., and Ngomo, A. N. 2016. Survey on Challenges of Question Answering in the Semantic Web Proceedings. Semantic Web, pp. 1–26.

Hovy, E., Gerber, L., Hermjakob, U., Junk, M., and Lin, C.Y. 2000. Question Answering in Webclopedia. In Proceedings of TREC, Gaithersburg, MD.

Iftene, A. 2009. Textual Entailment. Ph.D Thesis, Al. I. Cuza University, Faculty of Computer Science, Iasi, Romania.

Indurkhya, N., and Damereau, F. J. 2010. Handbook of Natural Language Processing. second ed. Chapman and Hall/CRC, Boca Raton.

Ittycheriah, A., Franz, M., Zhu, W. J., Ratnaparkhi, A., and Mammone, R. J. 2000. IBM’s statistical question answering system, In Proceedings of the Text Retrieval Conference TREC-9.

Jijkoun, V., and de Rijke, M. 2006. Overview of the WiQA Task at CLEF 2006, In 7th Workshop of the Cross-Language Evaluation Forum, CLEF, Revised Selected Papers.

Jones, S. 1972.Astatisticalinterpretation of term specificity and its application in retrieval. Journal of documentation, 28(1):11–21.

Juan, L., Chunxia, Z., and Zhendong, N. 2016. Answer Extraction Based on Merging Score Strategy of Hot Terms. Chinese Journal of Electronics, 25(4).

Jurafsky, D., and Martin, J.H. 2015. Question Answering. In: Computational Linguistics and speech recognition. Speech and Language Processing. Colorado.

Kan, K.L., and Lam, W. 2006. Using semantic relations with world knowledge for question answering. In: Proceedings of TREC.

Katz, B. 2017. http://start.csail.mit.edu/index.php.

Katz, Felshin, B., Yuret, S., Ibrahim, D., and Temelkuran, B. 2002. OmnIbase: uniform access to heterogeneous data for question answering, In: Proceedings of the 7th International Workshop on Applications of Natural Language to Information Systems (NLDB).

Kaur, and Gupta, V. 2013. Effective Question Answering Techniques and their Evaluation Metrics. International Journal of Computer Applications, 65(12):30–7.

Kolomiyets, O. 2011. A survey on question answering technology from an information retrieval perspective. Inf. Sci. 181(24):5412–34.

Kosseim, L., Plamondon, L., and Guillemette, L. J. 2003. Answer Formulation for Question-Answering. In: Xiang Y., Chaib-draa B. (eds) Advances in Artificial Intelligence, AI 2003, Lecture Notes in Computer Science, 2671.

Kumar, S. G., and Zayaraz, G. 2014. Concept relation extraction using NaIve Bayes classifier for ontology-based question answering systems. J. King Saud Univ.

Kwok, C., Etzioni, O., and Weld, D.S. 2001. Scaling question answering to the Web. ACM Transactions on Information Systems (TOIS), 19 (3):242–62.

Lally, Prager, J. M., McCord, M. C., Boguraev, B. K., Patwardhan, S., Fan, J., Fodor, and P., Chu-Carroll, J. 2012. Question analysis: How Watson Reads a clue. IBM J. RES. and DEV . 56(¾), pp. 1–14.

Lamel, L., Rosset, S., Ayache, C., Mostefa, D., Turmo, J., and Comas, P. 2007. Question Answering on Speech Transcriptions: the QAST Evaluation in CLEF, In 8th Workshop of the Cross-Language Evaluation Forum, CLEF 2007, Budapest, Hungary, Revised Selected Papers.

Lebedeva, O. and Zaitseva, L. 2015. Question Answering Systems in Education and their Classifications. In: Proceedings of Joint International Conference on Engineering Education and International Conference on Information Technology (ICEE/ICIT 2014), Latvia, RĪga. Riga: RTU Press, pp. 359–366.

Lee, Y. H., Lee, C. W., Sung, C. L., Tzou, M. T., Wang, C. C., Liu, S. H., Shih, C. W., Yang, P. Y., and Hsu, W. L. 2008. Complex question answering with ASQA at NTCIR-7 ACLIA, In Proceedings of NTCIR-7 Workshop Meetings, Entropy, 1(10).

Li, X. and Roth, D. 2002. Learning question classifiers, In: Proceedings of the 19th International Conference on Computational Linguistics (COLING’02).

Li, X., and Roth, D. 2005. Learning question classifiers: The role of semantic information. Journal of Natural Language Engineering, 11(4):2005.

Lin, J., Quan, D., Sinha, V., Bakshi, K., Huynh, D., Katz, B., and Karger, D.R. 2003. What Makes a Good Answer? The Role of Context in Question Answering, MIT AI Laboratory/LCS Cambridge, MA 02139, USA.

Lopeza, V., and Uren, V. 2011. Is question answering fit for the semantic web?. Published in: Journal Semantic Web archive. IOS Press Amsterdam, Netherland. 2(2): 125–55.

Magnini, B., Romagnoli, S., Vallin, A., Herrera, J., Peñas, A., Peinado, V., Verdejo, F., and Rijke, M. 2003. The Multiple Language Question Answering Track at CLEF 2003, In C. Peters, J. Gonzalo, M. Braschler, M. Kluck (Eds.), Comparative Evaluation of Multilingual Information Access Systems, 4th Workshop of the Cross-Language Evaluation Forum, CLEF, Trondheim, Norway, Revised Selected Papers.

Melo, D., Rodrigues, I.P., and Nogueira, V.B. 2012. A Review on Cooperative Question-Answering Systems. Instituto Polit´ecnico de Coimbra e CENTRIA, Portugal.

Miller, G. 1995. Wordnet: a lexical database for English. ACM, 38 (11):39–41.

Mishra, A. 2010. Context aware restricted domain geographical question answering systems, In: International Conference on Computational Intelligence and Communication Networks (CICN), pp. 26–8.

Mishra, A., and Jain, S.K. 2015. A survey on question answering systems with classification, Journal of King Saud University. Computer and Information Sciences, 28(3), 345–61.

Moldovan, D., Harabagiu, S., and Pasca, M. 2000. The structure and performance of an open-domain question answering system, In: Proceedings of the 38th Annual Meeting on Association for Computational Linguistics, pp. 563–70.

Moldovan, D., Pasca, M., and Harabagiu, S. 2003. Performance issues and error analysis in an open-domain question answering system. ACM Trans. Information System.

Molla, D., and Vicedo, J. E. L. 2007. Question answering in restricted domains: an overview, In: Proceedings of Association for Computational Linguistics.

Mollaei, Rahati-Quchani, S., and Estaji, A. 2012. Question classification in Persian language based on conditional random fields. Proceedings of 2nd International Conference Computer and Knowledge Engineering (ICCKE), IEEE.

Monz, C. 2004. Minimal span weighting retrieval for question answering, In SIGIR Workshop on Information Retrieval for Question Answering, pp. 23–30.

Moschitti, A. 2003. Answer filtering via text categorization in question answering systems, In Proceedings of the 15th IEEE International Conference on Tools with Artificial Intelligence, pp. 241–248.

Murdock, J. W., and Tesauro, G. 2016. Statistical Approaches to Question Answering. IBM TJ Watson Research Center.

Na, S. H., Kang, I. S., Lee, S. Y., and Lee, J. H. 2002. Question answering approach using a wordnet-based answer type taxonomy. In Proceedings of TREC.

Nalawade, S., Kumar, S., and Tiwari, D. 2012. Question Answering System, International Journal of Science and Research (IJSR). ISSN (ONLINE):2319–7064.

Neumann, G., and Sacaleanu, B. 2005. DFKI’s LT-lab at the CLEF 2005 Multiple Language Question Answering Track, Working Notes CLEF, Vienna, Austria.

Ng, J. P., and Kan, M.Y. 2010. QANUS: An Open-source Question-Answering Platform. CoRR, abs/1501.00311.

Pakray, P., Bhaskar, P., Banerjee, S., Chandra Pal, B., Bandyopadhyay, S., and Gelbukh. A. 2011. A Hybrid Question Answering System based on Information Retrieval and Answer Validation. DBLP Conference: CLEF 2011 Labs and Workshop, Notebook Papers, Amsterdam, Netherlands. citeseerx.ist.psu.edu/viewdoc/summary?doi=

Park, S., Kwon, S., Kim, B., Han, S., Shim, H., and Lee, G.G. 2015. Question Answering System using Multiple Information Source and Open Type Answer Merge. Pohang University of Science and Technology, Pohang, Republic of Korea.

Pasca, M.A., and Harabagiu, S.M. 2001. High performance question answering. In Proceedings of SIGIR, pp. 366–74.

Pasca. M. 2003. Open-Domain Question Answering from Large Text Collections. University of Chicago Press.

Perera, R. 2012. Ipedagogy: Question answering system based on web information clustering. IEEE Fourth International Conference on Technology for Education, pp. 245–6.

Pérez, A.R., Gómez, M.M., and Pineda, L.V. 2007. Enhancing CrossLanguage Question Answering by Combining Multiple Question Translations, CICLing-2007, Lecture Notes in Artificial Intelligence 4394, Springer.

Peyet, G., Pradel, Haemmerle, O., and Hernandez, N. 2013. SWIP at QALD- 3: Results, criticisms and lesson learned, In Forner, P., Navigli, R., Tufis, D., Ferro, N., Working Notes for CLEF 2013 Conference, Valencia, Spain, 1179.

Prager, J., Brown, E., Coden, A., and Radev, D. 2000. Question-Answering by predictive annotation, In proceedings of the 23rd SIGIR Conference, pp. 184–191.

Pundge, A.M., Khillare, S.A., and Mahender, C.N. 2016. Question Answering System, Approaches and Techniques: A Review, International Journal of Computer Applications, 141(3):0975–8887.

Quarteroni, S., and Manandhar, S. 2007. User Modelling for Personalized Question Answering. In: Basili R., Pazienza M.T. (eds) AI*IA 2007: Artificial Intelligence and Human-Oriented Computing. AI*IA 2007. Lecture Notes in Computer Science, 4733. Springer, Berlin, Heidelberg.

Quarteroni, S., and Manandhar, S. 2009. Designing an interactive opendomain question answering system. Natural Language Engineering, 15(1):73–95.

Radev, Fan, W., Qi, H., Wu, H., and Grewal, A. 2002. Probabilistic question answering on the web. Proceedings of the 11th international conference on World Wide Web, ACM.

Ramakrishnan, G., Chakrabarti, S., Paranjpe, D., and Bhattacharya, P. 2004. Is question answering an acquired skill? In Proceedings of the 13th ACM international conference on World Wide Web, pp. 111–20.

Ravichandran, D., and Hovy, E.H. 2002. Learning surface text patterns for a question answering system, In Proceedings of ACL, pp. 41–7.

Ravichandran, D., Ittycheriah, A., and Roukos, S. 2003. Automatic derivation of surface text patterns for a maximum entropy based question answering system, In Proceedings of HLT-NAACL.

Riloff, E., and Thelen, M. 2000. A rule-based question answering system for reading comprehension tests, In: ANLP/NAACL Workshop on Reading Comprehension Tests as Evaluation for Computer-Based Language Understanding Systems, 6:13–9.

Rosso, P., Buscaldi, D., and Iskra, M. 2007. Web-based Selection of Optimal Translations of Short Queries. Procesamiento de Lenguaje Natural, 38.

Saini, A., and Yadav, P.K. 2017. A Survey on Question Answering System. International Journal of Engineering and Computer Science ISSN:2319-7242, 6(3):20453–57.

Sanchez, P., Martinez, J. L., Ledesma, AG., Samy, D., Martinez, P., Sandoval, A. M., and Al-Jumaily, H. 2007. MIRACLE Question Answering System for Spanish at CLEF.

Sangodiah, A., Muniandy, M., and Heng, L. E. 2015. Question classification using statistical approach: a complete review, Journal of theoretical and applied information technology, 71(3).

Sangoi-Pizzato, L.A., and Molla-Aliod, D. 2005. Extracting Exact Answers using a Meta Question Answering System. Australasian Language Tech-nology Workshop, Australia.

Sasikumar, U., and Sindhu, L. 2014. A survey of Natural Language question answering system. international journal of computer applications (09758887), 108(15).

Saxena, A.K., Sambhu, G.V., Kaushik, S., and Subramaniam, L.V. 2007. System for question answering using pattern matching, semantic type and semantic category recognition, In Proceedings of the TREC, 2.

Schlaefer, N. 2011. Statistical Source Expansion for Question Answering. In: Proceeding CIKM ’11 Proceedings of the 20th ACM international conference on Information and knowledge management pp. 345–54.

Shekarpour, S., Marx, E., Ngomo, A.C.N., and Auer, S. 2015. Sina: Semantic interpretation of user queries for question answering on interlinked data. Web Semantics: Science, Services and Agents on the World Wide Web.

Shen, Dan, Kruijff, G.M., and Klakow, D. 2005. Exploring syntactic relation patterns for question answering. In Proceedings of the Second International Joint Conference on Natural Language Processing (IJCNLP), Jeju Island, Republic of Korea.

Sobrino, A., Olivas, J.A., and Puente, C. 2012. Mining answers for causal questions in a medical example. In: Intelligent Systems Design and Application (ISDA) 11th International Conference, IEEE, Cordoba, Spain.

Soricut, R., and Brill, E. 2006. Automatic question answering using the web: Beyond the factoid, In Journal of Information Retrieval-Special Issue on Web Information Retrieval, 9(2):191–206.

Soubbotin, M. M. 2001. Patterns of potential answer expressions as clues to the right – answers, In Proceedings of TREC, pp. 293–302.

SPARQL. 2007. Query Language for RDF. http://www.w3.org/TR/rdf-sparqlquery/.

Stupina, A. A., Shigina,A.A., Shigin,A. O., Karaseva, M.V., and Korpacheva, L. N. 2016. Question Answering system. IOP Conf. Ser.: Mater. Sci. Eng. 155 012024.

Sun, H., Duan, N., Duan, Y., and Zhou, M. 2013. Answer Extraction from Passage Graph for Question Answering. In Proceedings of the Twenty-Third International Joint Conference on Artificial Intelligence.

Sun, H., Ma, H., Yih, W., Tsai, C., Liu, J. and Chang, M. 2015. Open domain Question Answering via semantic enrichment. In Gangemi, A., Leonardi, S., and Panconesi, A. editors, Proceedings of the 24th International Conference on World Wide Web, Florence, Italy, pp. 1045–55.

Sutcliffe, R., Mulcahy, M., Gabbay, I., O’Gorman, A., White, K., and Slatter, D. 2005. Cross-Language French-English Question Answering using the DLT System at CLEF.

Suzuki, J., Sasaki, Y., and Maeda, E. 2002. SVM answer selection for open domain question answering, In Proceedings of 19th International Conference on Computational linguistics, COLING’02, 1, pp. 1–7.

Thompson, K. C., and Callan, J. P. 2007. Estimation and use of uncertainty in pseudo-relevance feedback, SIGIR.

Tiedemann, J. 2005. Integrating linguistic knowledge in passage retrieval for question answering. In Proceedings of EMNLP, pp. 939–946.

Tirpude, S. 2015. Closed Domain Question Answering System: A Survey, ISSN (Online): 2347–1697 International Journal of Informative and Futuristic Research (IJIFR) 2(9):334–5.

Unger, C., Bühmann, L., Lehmann, J., Ngonga Ngomo, A.C., Gerber, D., and Cimiano, P. 2012. Template-based question answering over RDF data. In Proceedings of the ACM 21st international conference on World Wide Web, pp. 639–48.

Usbeck R., Ngomo AC. N., Bühmann L., Unger C. (2015) HAWK – Hybrid Question Answering Using Linked Data. In: Gandon F., Sabou M., Sack H., d’Amato C., Cudré-Mauroux P., Zimmermann A. (eds) The Semantic Web. Latest Advances and New Domains. ESWC 2015. Lecture Notes in Computer Science, 9088. Springer, Cham.

Vanitha, Sanampudi, S. K., and Lakshmi, I. M. 2010. Approaches for question answering system. IJEST, 3:992–5.

Verberne, S., Boves, L., Oostdijk, N., and Coppen, P.A. 2008. Using syntactic information for improving why-question answering. In: Proceedings of the 22nd International Conference on Computational Linguistics (COLING), pp. 953–60.

Verberne, S., Boves, L., Oostdijk, N., and Coppen, P.A. 2007. Discourse based answering of why-questions, In: Traitement Automatique des Langues (TAL), special issue on “Discourse document: traitements automatiques”, 47(2):21–41.

Verberne, S., Boves, L., Oostdijk, N., and Coppen, P.A. 2010. What is not in the bag of words for why-QA? Computational Linguistics, 32(2).

Vicedo, J. L., and Molla, D. 2001. Open-domain question-answering technology: state of the art and future trends. ACM J.2(3):1–44.

Voorhees, E., and Weishedel, R. 2000. Issues, tasks and program structures to roadmap research in question and answering (QandA). University of Utah, riloff@cs.utah.edu.

Voorhees, E. M. 2001. The TREC question answering track. Nat. Lang. Eng. 7 (4):361–378.

Voorhees, E. M. 2004. Overview of the TREC 2003 question answering Track. Twelfth Text Retrieval Conference, 500(255) of NIST Special Publications, Gaithersburg, MD.

Wade, C., and Allan, J. 2005. Passage Retrieval and Evaluation. Center for Intelligent Information Retrieval Department of Computer Science University of Massachusetts Amherst, MA 01003.

Wang, L., Zhang, H., Wang, D., and Huang, J. 2009. Chinese Question Classification Based on Semantic Gram and SVM, Proc. of International Forum on Computer Science Technology and Applications, IEEE.

Webb, and Strzalkowski, T. 2006. Proceedings of the Interactive Question Answering Workshop at HLT-NAACL.

Weizenbaum, J. 1966. ELIZA: a computer program for the study of natural language communication between man and machine. In Communications of the ACM, 9(1):36–45.

Wenyin, L., Hao, T., Chen, W., and Feng, M. 2009. A Web-Based Platform for User-Interactive Question-Answering. World Wide Web. Springer US. 12: 107. https://doi.org/10.1007/s11280-008-0051-3

Wong, W. 2004. Practical approach to knowledge-based question answering with natural language understanding and advanced reasoning (MSc thesis). Kolej Universiti Teknikal Kebangsaan Malaysia.

Woods, W. 1973. Progress in Natural Language Understanding – An ApplIcation to Lunar Geology, In Proceedings of AFIPS Conference, 42: 441–50.

Wu, Y., Kashioka, H., and Zhao, J. 2007. Using Clustering Approaches to Open-Domain Question Answering, In: Gelbukh A. (eds) Computational Linguistics and Intelligent Text Processing, Lecture Notes in Computer Science, 4394.

Xia, L., Teng, Z., and Ren, F. 2008. An Integrated Approach for Question Classification in Chinese Cuisine Question Answering System. In IEEE second International Symposium on Universal Communication, pp. 317–21.

Xianfeng, Y., and Pengfei, L. 2016. Question Recommendation and Answer Extraction in Question Answering Community. International Journal of Database Theory and Application, 9 (1):35–44.

Xu, J., Licuanan, A., May, J., Miller, S., and Weischedel, R. 2003. Answer selection and confidence estimation, In AAA iSpring Symposium on New Directions in QA.

Xu, K., Feng, Y., and Zhao, D. 2014. Xser@QALD-4: Answering natural language questions via Phrasal Semantic Parsing. In Cappellato, L., Ferro, N., Halvey, M., and Kraaij, W. editors, Working Notes for CLEF 2014 Conference, Sheffield, UK, CEUR Workshop Proceedings, 1180:1260–74.

Yang, H., Cui, H., Maslennikov, M., Qiu, L., Kan, M. Y., and Chua, T. S. 2003. Qualifier in TREC-12 QA main task. In Proceedings of TREC.

Yogish, D., Manjunath, T. N., and Hegadi, R. S. 2016. A Survey of Intelligent Question Answering System Using NLP and Information Retrieval Techniques. International Journal of Advanced Research in Computer and Communication Engineering, 5(5).

Zhang, D., and Lee, W. S. 2002. Web based pattern mining and matching approach to question answering, In Proceedings of the 11th Text Retrieval Conference.

Zhang, K., and Zhao, J. 2010. A Chinese question answering system with question classification and answer clustering, In Proceedings of IEEE International Conference on Fuzzy Systems and Knowledge Discovery (FSKD), 6:2692–96.

Zheng, Z. 2002. The AnswerBus Question Answering System in Proceedings of Human Language Technology Conference HLT, San Diego, CA.