From dyogatama at cs.cmu.edu Mon Mar 31 17:39:38 2014 From: dyogatama at cs.cmu.edu (Dani Yogatama) Date: Mon, 31 Mar 2014 17:39:38 -0400 Subject: [CL+NLP Lunch] CL+NLP Lunch, Dan Garrette, April 10 @noon Message-ID: *CL+NLP Lunch *(*http://www.cs.cmu.edu/~nlp-lunch/ *) *Speaker*: Dan Garrette, The University of Texas at Austin *Date*: Thursday, April 10, 2013 *Time*: 12:00 noon *Venue*: GHC 6501 *Title*: Unsupervised learning of non+concatenative morphology *Abstract*: Grammar learning is a well-studied problem in NLP, but the task is particularly difficult for low-resource languages. In this talk, I will discuss our current work in learning combinatory categorial grammars from various forms of weak supervision. First, I will show how we can learn good sequence-based CCG supertaggers by encoding universal, inherent properties of the CCG formalism as priors over both the appearance of supertags and the transitions between supertags. These universal priors can, in turn, be combined with corpus-specific knowledge derived from available (partial) tag dictionaries and unannotated text to further improve tagging performance. Then, I will discuss our current efforts to extend these principles to tree grammars to learn CCG parsers. Finally, I will discuss how simple annotations --- particularly those given in the Graph Fragment Language developed at CMU --- may be used to help learn parsers under extremely tight annotation budgets. This work is in collaboration with Jason Baldridge, Chris Dyer, and Noah Smith. *Biography*: Dan is a a Computer Science Ph.D. student at The University of Texas at Austin. His research focuses on Natural Language Processing and Machine Learning. He was a Best Talk Award nominee at NAACL this past year. He thinks slides should have less text and more animations. -------------- next part -------------- An HTML attachment was scrubbed... URL: From dyogatama at cs.cmu.edu Thu Apr 10 00:03:46 2014 From: dyogatama at cs.cmu.edu (Dani Yogatama) Date: Thu, 10 Apr 2014 00:03:46 -0400 Subject: [CL+NLP Lunch] CL+NLP Lunch, Dan Garrette, April 10 @noon In-Reply-To: References: Message-ID: reminder tomorrow at noon On Monday, March 31, 2014, Dani Yogatama wrote: > *CL+NLP Lunch *(*http://www.cs.cmu.edu/~nlp-lunch/ > *) > *Speaker*: Dan Garrette, The University of Texas at Austin > *Date*: Thursday, April 10, 2013 > *Time*: 12:00 noon > *Venue*: GHC 6501 > > *Title*: Learning Combinatory Categorial Grammars from Wrak Supervision > > *Abstract*: > Grammar learning is a well-studied problem in NLP, but the task is > particularly difficult for low-resource languages. In this talk, I > will discuss our current work in learning combinatory categorial > grammars from various forms of weak supervision. First, I will show > how we can learn good sequence-based CCG supertaggers by encoding > universal, inherent properties of the CCG formalism as priors over > both the appearance of supertags and the transitions between > supertags. These universal priors can, in turn, be combined with > corpus-specific knowledge derived from available (partial) tag > dictionaries and unannotated text to further improve tagging > performance. Then, I will discuss our current efforts to extend these > principles to tree grammars to learn CCG parsers. Finally, I will > discuss how simple annotations --- particularly those given in the > Graph Fragment Language developed at CMU --- may be used to help > learn parsers under extremely tight annotation budgets. > > This work is in collaboration with Jason Baldridge, Chris Dyer, and Noah > Smith. > > *Biography*: > Dan is a a Computer Science Ph.D. student at The University of Texas > at Austin. His research focuses on Natural Language Processing and > Machine Learning. He was a Best Talk Award nominee at NAACL this > past year. He thinks slides should have less text and more animations. > > -------------- next part -------------- An HTML attachment was scrubbed... URL: From cdyer at cs.cmu.edu Thu May 8 14:28:14 2014 From: cdyer at cs.cmu.edu (Chris Dyer) Date: Thu, 8 May 2014 14:28:14 -0400 Subject: [CL+NLP Lunch] CL-NLP-MT Lunch, Stefan Riezler, May 13 @ noon Message-ID: *Speaker*: Stefan Riezler, Heidelberg University (http://www.cl.uni-heidelberg.de/~riezler/) *Date*: Tuesday, May 13, 2014 *Time*: 12:00 noon *Venue*: GHC 6501 *Title: *Theoretical and Practical Grounding in Empirical Computational Linguistics *Abstract*: Philosophy of science has pointed out a circularity problem in empirical sciences that arises if all known measuring procedures for a quantity of a theory presuppose the validity of this theory. We discuss how this problem relates to empirical computational linguistics, and define a criterion of T-non-theoretical grounding as guidance to avoid such circularities. We exemplify how this criterion can be met by crowdsourcing, task-related data annotation, or data in the wild. In particular, we illustrate the benefits of grounded learning in the area of statistical machine translation, e.g., by grounding machine translation in semantic parsing and in cross-lingual information retrieval. *Bio*: Prof. Stefan Riezler has been appointed full professor and head of the chair of Linguistic Informatics at Heidelberg University in 2010, after spending a decade in the world?s most renowned industry research labs (Xerox PARC, Google). He received his PhD in Computational Linguistics from the University of T?bingen in 1998, and then conducted post-doctoral work at Brown University in 1999. Prof. Riezler's research focus is on machine learning and statistics applied to natural language processing problems, especially for the application areas of natural-language based web search and statistical machine translation. -------------- next part -------------- An HTML attachment was scrubbed... URL: From cdyer at cs.cmu.edu Mon May 12 17:41:32 2014 From: cdyer at cs.cmu.edu (Chris Dyer) Date: Mon, 12 May 2014 17:41:32 -0400 Subject: [CL+NLP Lunch] CL-NLP-MT Lunch, Stefan Riezler, May 13 @ noon In-Reply-To: References: Message-ID: Reminder everyone: this is Tuesday at 12 in 6501. Come welcome our new visitor, Stefan! On Thu, May 8, 2014 at 2:28 PM, Chris Dyer wrote: > *Speaker*: Stefan Riezler, Heidelberg University > (http://www.cl.uni-heidelberg.de/~riezler/) > *Date*: Tuesday, May 13, 2014 > *Time*: 12:00 noon > *Venue*: GHC 6501 > > *Title: *Theoretical and Practical Grounding in Empirical Computational > Linguistics > > *Abstract*: > Philosophy of science has pointed out a circularity problem in empirical > sciences that arises if all known measuring procedures for a quantity of a > theory presuppose the validity of this theory. We discuss how this problem > relates to empirical computational linguistics, and define a criterion of > T-non-theoretical grounding as guidance to avoid such circularities. We > exemplify how this criterion can be met by crowdsourcing, task-related data > annotation, or data in the wild. In particular, we illustrate the benefits > of grounded learning in the area of statistical machine translation, e.g., > by grounding machine translation in semantic parsing and in > cross-lingual information retrieval. > > *Bio*: Prof. Stefan Riezler has been appointed full professor and head of > the chair of Linguistic Informatics at Heidelberg University in 2010, after > spending a decade in the world?s most renowned industry research labs > (Xerox PARC, Google). He received his PhD in Computational Linguistics from > the University of T?bingen in 1998, and then conducted post-doctoral work > at Brown University in 1999. Prof. Riezler's research focus is on machine > learning and statistics applied to natural language processing problems, > especially for the application areas of natural-language based web search > and statistical machine translation. > -------------- next part -------------- An HTML attachment was scrubbed... URL: From nathan at cmu.edu Wed Jun 18 16:38:14 2014 From: nathan at cmu.edu (Nathan Schneider) Date: Wed, 18 Jun 2014 16:38:14 -0400 Subject: [CL+NLP Lunch] Tim Baldwin talk: Friday at noon Message-ID: All, Join us Friday at noon for a talk by a very special visitor. Lunch will be provided. Cheers, Nathan NLP Lunch Friday, June 20 at noon GHC 8102 Tim Baldwin, University of Melbourne *Text Analysis of Social Media Beyond Twitterdome* Abstract: Text processing of social media data in NLP has largely centred around Twitter, with other social media types getting relatively little attention. In this talk, I will first present an empirical comparison of text sourced from a range of social media sites (microblogs, comments, user forums, blogs and Wikipedia), focusing on the relative "noisiness" and diversity of the linguistic content. I will then discuss the application of discourse parsing to user forum threads, and incorporation of the results to improve search quality. Bio: Tim Baldwin is a Professor in the Department of Computing and Information Systems, The University of Melbourne, an Australian Research Council Future Fellow, and a contributed research staff member of NICTA Victoria. He has previously held visiting positions at the University of Washington, University of Tokyo, Saarland University, NTT Communication Science Laboratories and National Institute of Informatics. His research interests include text mining of social media, computational lexical semantics, information extraction and web mining, with a particular interest in the interface between computational and theoretical linguistics. Current projects include web user forum mining, text mining of Twitter, and machine translation evaluation. He is currently Secretary of the Australasian Language Technology Association and a member of the Executive Committee of the Asian Federation of Natural Language Processing, and was recently PC Chair of EMNLP 2013 and *SEM 2013. Tim completed a BSc(CS/Maths) and BA(Linguistics/Japanese) at The University of Melbourne in 1995, and an MEng(CS) and PhD(CS) at the Tokyo Institute of Technology in 1998 and 2001, respectively. Prior to joining The University of Melbourne in 2004, he was a Senior Research Engineer at the Center for the Study of Language and Information, Stanford University (2001-2004). -------------- next part -------------- An HTML attachment was scrubbed... URL: From dcard at andrew.cmu.edu Mon Jul 14 16:24:09 2014 From: dcard at andrew.cmu.edu (Dallas Card) Date: Mon, 14 Jul 2014 16:24:09 -0400 Subject: [CL+NLP Lunch] CL+NLP Lunch, Walid Magdy, July 18 @ 12:30pm Message-ID: <70a207f3cf35a8de4b155a0ccc257eb5.squirrel@webmail.andrew.cmu.edu> CL+NLP lunch Friday, July 18 at 12:30pm GHC 8012 Walid Magdy, Qatar Computing Research Institute *Social Media as a Source of Unbiased News* Abstract: News media are usually biased toward some political views. Also, the coverage of news is limited to news reported by news agencies. Social media is currently a hub for users to report and discuss news. This includes news reported or missed by news media. Developing a system that can generate news reports from social media can give a global unbiased view on what is hot in a given region. In this talk, the challenges for tracking topics related to news are discussed. An automatically adapting information filtering approach is presented that allows tracking broad and dynamic topics in social media. TweetMogaz, a news portal platform that generated news from Twitter, is demoed. TweetMogaz reports in real-time what is happening in hot regions in the middle east, such as Syria and Egypt, in the form of comprehensive reports that include top tweets, images, videos, and news article shared by users on Twitter. Bio: Walid Magdy is a scientist at the Qatar Computing Research Institute (QCRI) in Doha, Qatar. Walid's main fields of expertise are information retrieval and natural language processing. He received his PhD in 2012 from the School of Computing in Dublin City University (DCU), Dublin, Ireland. Earlier, he received his BSc. and Msc. from the Faculty of Engineering, Cairo University, Egypt in 2005 and 2008 respectively. He worked before as research engineer in Microsoft and IBM. Walid has a list of publications in top tier conferences and journals, such as SIGIR, CIKM, EMNLP, ICWSM, ECIR, IRJ, and TOIS. He also has a set of filed and issued patents during his work in IBM, Microsoft, DCU, and QCRI. From dcard at andrew.cmu.edu Fri Jul 18 09:52:33 2014 From: dcard at andrew.cmu.edu (Dallas Card) Date: Fri, 18 Jul 2014 09:52:33 -0400 Subject: [CL+NLP Lunch] Reminder: Today at 12:30pm: CL+NLP Lunch, Walid Magdy, *GHC 8102* Message-ID: Reminder: Today at 12:30pm! Please join us this Friday for a talk by Walid Magdy from the Qatar Computing Research Institute. Lunch will be provided! CL+NLP lunch Friday, July 18 at 12:30pm GHC 8102 Walid Magdy, Qatar Computing Research Institute *Social Media as a Source of Unbiased News* Abstract: News media are usually biased toward some political views. Also, the coverage of news is limited to news reported by news agencies. Social media is currently a hub for users to report and discuss news. This includes news reported or missed by news media. Developing a system that can generate news reports from social media can give a global unbiased view on what is hot in a given region. In this talk, the challenges for tracking topics related to news are discussed. An automatically adapting information filtering approach is presented that allows tracking broad and dynamic topics in social media. TweetMogaz, a news portal platform that generated news from Twitter, is demoed. TweetMogaz reports in real-time what is happening in hot regions in the middle east, such as Syria and Egypt, in the form of comprehensive reports that include top tweets, images, videos, and news article shared by users on Twitter. Bio: Walid Magdy is a scientist at the Qatar Computing Research Institute (QCRI) in Doha, Qatar. Walid's main fields of expertise are information retrieval and natural language processing. He received his PhD in 2012 from the School of Computing in Dublin City University (DCU), Dublin, Ireland. Earlier, he received his BSc. and Msc. from the Faculty of Engineering, Cairo University, Egypt in 2005 and 2008 respectively. He worked before as research engineer in Microsoft and IBM. Walid has a list of publications in top tier conferences and journals, such as SIGIR, CIKM, EMNLP, ICWSM, ECIR, IRJ, and TOIS. He also has a set of filed and issued patents during his work in IBM, Microsoft, DCU, and QCRI. From dcard at andrew.cmu.edu Wed Jul 30 16:58:19 2014 From: dcard at andrew.cmu.edu (Dallas Card) Date: Wed, 30 Jul 2014 16:58:19 -0400 Subject: [CL+NLP Lunch] CL+NLP Lunch, Archna Bhatia, August 5 @ 2:00pm Message-ID: <3d323ef9558cb2c9847697a79049cfe2.squirrel@webmail.andrew.cmu.edu> Please join us for the next CL+NLP lunch at 2pm on August 5th, where Archna Bhatia will be speaking about the cross-linguistic study of form-function mappings. Lunch will be provided! CL+NLP lunch Tuesday, August 5th at 2:00pm GHC 6501 Archna Bhatia, LTI *Studying form-function mappings cross-linguistically* Abstract: Languages carry form-function mappings, and while this property is shared across languages, the exact same mappings are not. Cross-linguistic studies of these mappings enable us to study the extent of systematicity and the range of variation observed in the mappings across languages. This can, in turn, shed some light on the nature of human language. In this talk, I present our recent efforts to explore a phenomenon, definiteness, which expresses the mapping between morphosyntax and the semantic, pragmatic and discourse properties of noun phrases. Starting with a novel language-independent annotation scheme for definiteness, and statistical modeling of communicative functions, this work provides insight into the form-function mappings of English noun phrases. Besides aiding in an understanding of the nature of language in general, discoveries about the form-function mapping across languages hold promise for various NLP applications such as machine translation, knowledge base construction, and information retrieval. Bio: Archna Bhatia is a postdoctoral researcher in the Language Technologies Institute. She received her PhD in Linguistics from University of Illinois at Urbana-Champaign in 2011. In her thesis research, she focussed on the phenomenon of agreement in the context of coordination in Hindi and compared it with two genetically unrelated languages, one with the same and one with different word order properties. She is interested in developing an understanding of the nature of language by applying theoretical, descriptive, experimental and computational methods to study its structure and acquisition. She has collaborated with researchers in Linguistics, Computational Linguistics and Computer Science departments in this endeavor. -- Dallas Card Machine Learning Department Carnegie Mellon University From dcard at andrew.cmu.edu Tue Aug 5 09:51:59 2014 From: dcard at andrew.cmu.edu (Dallas Card) Date: Tue, 5 Aug 2014 09:51:59 -0400 Subject: [CL+NLP Lunch] Reminder: CL+NLP Lunch, Archna Bhatia, TODAY @ 2:00pm Message-ID: <24d697b8fde59e854996bae3f344aee3.squirrel@webmail.andrew.cmu.edu> Please join us for the next CL+NLP lunch at 2pm on August 5th, where Archna Bhatia will be speaking about the cross-linguistic study of form-function mappings. Lunch will be provided! CL+NLP lunch Tuesday, August 5th at 2:00pm GHC 6501 Archna Bhatia, LTI *Studying form-function mappings cross-linguistically* Abstract: Languages carry form-function mappings, and while this property is shared across languages, the exact same mappings are not. Cross-linguistic studies of these mappings enable us to study the extent of systematicity and the range of variation observed in the mappings across languages. This can, in turn, shed some light on the nature of human language. In this talk, I present our recent efforts to explore a phenomenon, definiteness, which expresses the mapping between morphosyntax and the semantic, pragmatic and discourse properties of noun phrases. Starting with a novel language-independent annotation scheme for definiteness, and statistical modeling of communicative functions, this work provides insight into the form-function mappings of English noun phrases. Besides aiding in an understanding of the nature of language in general, discoveries about the form-function mapping across languages hold promise for various NLP applications such as machine translation, knowledge base construction, and information retrieval. Bio: Archna Bhatia is a postdoctoral researcher in the Language Technologies Institute. She received her PhD in Linguistics from University of Illinois at Urbana-Champaign in 2011. In her thesis research, she focussed on the phenomenon of agreement in the context of coordination in Hindi and compared it with two genetically unrelated languages, one with the same and one with different word order properties. She is interested in developing an understanding of the nature of language by applying theoretical, descriptive, experimental and computational methods to study its structure and acquisition. She has collaborated with researchers in Linguistics, Computational Linguistics and Computer Science departments in this endeavor. -- Dallas Card Machine Learning Department Carnegie Mellon University From dcard at andrew.cmu.edu Fri Aug 8 12:14:49 2014 From: dcard at andrew.cmu.edu (Dallas Card) Date: Fri, 8 Aug 2014 12:14:49 -0400 Subject: [CL+NLP Lunch] CL+NLP Lunch, Kevin Gimpel, Friday August 15 @ 2:00pm Message-ID: <8f554f7b9db39fe3101e7a6ed8d28050.squirrel@webmail.andrew.cmu.edu> Please join us for the next CL+NLP lunch at 2pm on August 15th, where Kevin Gimpel will be speaking about weakly-supervised NLP with cost-augmented contrastive estimation. Lunch will be provided! If you would like to set up a meeting with Kevin on August 15th, please email Dallas Card . CL+NLP lunch Friday, August 15th at 2:00pm GHC 8102 Kevin Gimpel, Toyota Technological Institute at Chicago *Weakly-Supervised NLP with Cost-Augmented Contrastive Estimation* Abstract: Unsupervised NLP aims to discover meaningful structure in unannotated text, such as parts-of-speech, morphological segmentation, or syntactic structure. Unsupervised systems improve when researchers incorporate knowledge to bias learning to better capture characteristics of the desired structure. Contrastive estimation (CE; Smith and Eisner, 2005) is a general approach to unsupervised learning with a particular way of incorporating knowledge. CE increases the likelihood of the observations at the expense of those in a particular neighborhood of each observation. The neighborhood typically contains corrupted versions of the observations. In this talk, we generalize CE in two ways that allow us to add more knowledge to unsupervised learning (thereby adding "weak" supervision). In particular, we augment CE with two types of cost functions, one on observations and one on output structures. The first allows the modeler to specify not only the set of corrupted inputs for each observation, but also how bad each one is. The second lets us specify preferences on desired output structures, regardless of the input sentence. We evaluate our approach, which we call cost-augmented contrastive estimation (CCE), on unsupervised part-of-speech tagging of five languages from the PASCAL 2012 shared task. We find that CCE improves over both standard CE and strong benchmarks from the shared task. This is joint work with Mohit Bansal. Bio: Kevin Gimpel is a research assistant professor at the Toyota Technological Institute at Chicago, a philanthropically-endowed academic computer science institute located on the campus of the University of Chicago. In 2012, he received his PhD from the LTI where he was advised by Noah Smith. His recent research focuses on machine translation, unsupervised learning, and structure prediction. -- Dallas Card Machine Learning Department Carnegie Mellon University From dcard at andrew.cmu.edu Fri Sep 26 15:46:49 2014 From: dcard at andrew.cmu.edu (Dallas Card) Date: Fri, 26 Sep 2014 15:46:49 -0400 Subject: [CL+NLP Lunch] CL+NLP Lunch, Kuzman Ganchev, Thursday October 2nd @ 1:00pm Message-ID: <4d012869acc0dc687aa372502862081e.squirrel@webmail.andrew.cmu.edu> Please join us for the next CL+NLP lunch at 1pm on October 2nd, where Kuzman Ganchev will be speaking about frame semantic parsing. Lunch will be provided! CL+NLP lunch Thursday, October 2nd at 1:00pm GHC 2109 Speaker: Kuzman Ganchev, Google Research *Title: Some recent work on frame semantics* Frame semantic parsing (sometimes called semantic role labeling) involves identifying the predicate argument structure of a sentence. For example in the sentence "I want to run a marathon.", "want" and "run" evoke frames, and the frame for "run" has the agent "I" and patient "a marathon". The frame for "run" in that sentence will be different from the frame for run in "I run the company". Frame semantic parsing is usually divided into frame identification and argument identification. I will present recent approaches from our group on each of these tasks: an embedding-based approach for frame identification, and a novel dynamic program for argument identification which allows computing posteriors and structured learning. Kuzman Ganchev was born in Sofia, Bulgaria. He received his Ph.D. in computer and information science from the University of Pennsylvania, and has been working as a research scientist at Google since 2010, where his research focuses on machine learning applied to natural language processing. -- Dallas Card Machine Learning Department Carnegie Mellon University From dcard at andrew.cmu.edu Tue Sep 30 19:22:33 2014 From: dcard at andrew.cmu.edu (Dallas Card) Date: Tue, 30 Sep 2014 19:22:33 -0400 Subject: [CL+NLP Lunch] Joint ML+NLP Lunch, Miguel Ballesteros, Monday October 6th @ 12:00pm Message-ID: <035ef0f3e4dae84991cbfe07150c531a.squirrel@webmail.andrew.cmu.edu> Please join us for a special joint ML+NLP lunch at noon on October 6th, where Miguel Ballesteros will be speaking about dependency parsing. Lunch will be provided! ML+NLP lunch Monday, October 6th at 12:00pm GHC 6115 Speaker: Miguel Ballesteros, Visiting Lecturer / Postdoc at Universitat Pompeu Fabra *Title: Going to the Roots of Dependency Parsing* In this seminar I will first introduce transition-based dependency parsing and present the conclusions extracted from a journal paper that I have never had the chance to present in public, besides I'm going to sum up my current, past and future research collaboration projects with some new results and developments. -- Dependency trees used in syntactic parsing often include a root node representing a dummy word prefixed or suffixed to the sentence, a device that is generally considered a mere technical convenience and is tacitly assumed to have no impact on empirical results. We demonstrate that this assumption is false and that the accuracy of data-driven dependency parsers can in fact be sensitive to the existence and placement of the dummy root node. In particular, we show that a greedy, left-to-right, arc-eager transition-based parser consistently performs worse when the dummy root node is placed at the beginning of the sentence (following the current convention in data-driven dependency parsing) than when it is placed at the end or omitted completely. Control experiments with an arc-standard transition-based parser and an arc-factored graph- based parser reveal no consistent preferences but nevertheless exhibit considerable variation in results depending on root placement. We conclude that the treatment of dummy root nodes in data-driven dependency parsing is an underestimated source of variation in experiments and may also be a parameter worth tuning for some parsers. Miguel is a Visiting lecturer - Postdoc in Pompeu Fabra University, Barcelona, Spain. He works on natural language processing and machine learning with a special interest on linguistic structure prediction problems, such as dependency parsing and phrase structure parsing. He completed his BsC, MsC and PhD at the Universidad Complutense de Madrid. During the last years, he was a Visiting Researcher in Universities of Uppsala, Birmingham and Singapore. -- Dallas Card Machine Learning Department Carnegie Mellon University From dcard at andrew.cmu.edu Thu Oct 2 08:44:49 2014 From: dcard at andrew.cmu.edu (Dallas Card) Date: Thu, 2 Oct 2014 08:44:49 -0400 Subject: [CL+NLP Lunch] Reminder: CL+NLP Lunch, Kuzman Ganchev, TODAY @ 1:00pm Message-ID: <190f6785c694c76a6bd9d203f1332071.squirrel@webmail.andrew.cmu.edu> CL+NLP lunch Thursday, October 2nd at 1:00pm GHC 2109 Speaker: Kuzman Ganchev, Google Research *Title: Some recent work on frame semantics* Frame semantic parsing (sometimes called semantic role labeling) involves identifying the predicate argument structure of a sentence. For example in the sentence "I want to run a marathon.", "want" and "run" evoke frames, and the frame for "run" has the agent "I" and patient "a marathon". The frame for "run" in that sentence will be different from the frame for run in "I run the company". Frame semantic parsing is usually divided into frame identification and argument identification. I will present recent approaches from our group on each of these tasks: an embedding-based approach for frame identification, and a novel dynamic program for argument identification which allows computing posteriors and structured learning. Kuzman Ganchev was born in Sofia, Bulgaria. He received his Ph.D. in computer and information science from the University of Pennsylvania, and has been working as a research scientist at Google since 2010, where his research focuses on machine learning applied to natural language processing. -- Dallas Card Machine Learning Department Carnegie Mellon University From dcard at andrew.cmu.edu Mon Oct 6 10:29:27 2014 From: dcard at andrew.cmu.edu (Dallas Card) Date: Mon, 6 Oct 2014 10:29:27 -0400 Subject: [CL+NLP Lunch] Reminder: Joint ML+NLP Lunch, Miguel Ballesteros, TODAY @ 12:00pm Message-ID: <6dcfa4d31ced9385389b694e492e692f.squirrel@webmail.andrew.cmu.edu> Please join us for a special joint ML+NLP lunch at noon today, where Miguel Ballesteros will be speaking about dependency parsing. Lunch will be provided! ML+NLP lunch Monday, October 6th at 12:00pm GHC 6115 Speaker: Miguel Ballesteros, Visiting Lecturer / Postdoc at Universitat Pompeu Fabra *Title: Going to the Roots of Dependency Parsing* In this seminar I will first introduce transition-based dependency parsing and present the conclusions extracted from a journal paper that I have never had the chance to present in public, besides I'm going to sum up my current, past and future research collaboration projects with some new results and developments. -- Dependency trees used in syntactic parsing often include a root node representing a dummy word prefixed or suffixed to the sentence, a device that is generally considered a mere technical convenience and is tacitly assumed to have no impact on empirical results. We demonstrate that this assumption is false and that the accuracy of data-driven dependency parsers can in fact be sensitive to the existence and placement of the dummy root node. In particular, we show that a greedy, left-to-right, arc-eager transition-based parser consistently performs worse when the dummy root node is placed at the beginning of the sentence (following the current convention in data-driven dependency parsing) than when it is placed at the end or omitted completely. Control experiments with an arc-standard transition-based parser and an arc-factored graph-based parser reveal no consistent preferences but nevertheless exhibit considerable variation in results depending on root placement. We conclude that the treatment of dummy root nodes in data-driven dependency parsing is an underestimated source of variation in experiments and may also be a parameter worth tuning for some parsers. Miguel is a Visiting lecturer - Postdoc in Pompeu Fabra University, Barcelona, Spain. He works on natural language processing and machine learning with a special interest on linguistic structure prediction problems, such as dependency parsing and phrase structure parsing. He completed his BsC, MsC and PhD at the Universidad Complutense de Madrid. During the last years, he was a Visiting Researcher in Universities of Uppsala, Birmingham and Singapore. From cdyer at cs.cmu.edu Fri Oct 17 20:17:36 2014 From: cdyer at cs.cmu.edu (Chris Dyer) Date: Fri, 17 Oct 2014 20:17:36 -0400 Subject: [CL+NLP Lunch] Sujith Ravi talk, Friday Oct 24, 11am (GHC 2109) Message-ID: Sujith Ravi (Google) will be on campus next Friday Oct 24 and giving a talk in GHC 2109 at 11am. Details below. If you would like to meet with the speaker, please indicate your availability here: https://docs.google.com/document/d/1JjaXfGzt4Y__B1_ORJejOWgJaeGPSo56zdnd0dPFoxU/edit?usp=sharing Title: Large-scale Structure Prediction for Natural Language Processing Abstract: Natural language processing (NLP) systems have become ubiquitous for data analysis in digital environments such as the Web and social media. While great progress has been made in a wide range of areas, building NLP systems from scratch still remains a daunting challenge for many applications, especially when there is a need to target different domains, languages or users. Current NLP systems heavily rely on expensive human-annotated data and struggle to effectively scale to the volume and characteristics of changing data environments, complex modeling choices and wide range of applications. Overcoming these challenges requires new advances in inference algorithms and efficient approximate learning methods that reduce the computational complexity involved in structured prediction problems. In this talk, I will present a series of new powerful general-purpose learning algorithms for large-scale structured prediction applicable to a wide range of tasks in NLP, IR, speech and computer vision. This work introduces novel algorithms for fast unsupervised and semi-supervised learning that address current challenges and unlike existing methods, the new approach scales to large data sizes and dimensionality as well as complex structured models. The new approaches fall under two major paradigms commonly used in machine learning: ?probabilistic inference? and ?graph optimization?. This talk will focus on the former---I will describe a new approach for fitting mixtures of exponential families, which generalizes several probabilistic models used in NLP and other areas. A major contribution of our work is a novel sampling method that uses randomized techniques like locality sensitive hashing to achieve high throughput in generating proposals during sampling. This method scales very easily to large data and model sizes achieving huge speedups of several orders of magnitude over existing toolkits and outperform state-of-the-art systems on a wide variety of structured prediction tasks ranging from clustering to topic modeling to machine translation. Moreover, we can efficiently parallelize the algorithm on modern computing platforms to achieve even higher throughputs. In addition, we also prove probabilistic error guarantees for the new algorithm. These novel techniques show great promise for tackling other complex AI problems such as deep language understanding and building joint models of language and vision. Bio: Sujith Ravi is a Research Scientist at Google since 2012. Prior to that he was a Research Scientist at Yahoo! Research. He completed his PhD at University of Southern California/Information Sciences Institute. His main research interests span various problems and theory related to the fields of Natural Language Processing (NLP) and Machine Learning. He won the SIGKDD 2014 Best Research Paper Award and a Best Paper Award nomination at ACL 2009. He is specifically interested in large-scale unsupervised and semi-supervised methods and their applications to structured prediction problems in NLP, information extraction, multi-modal learning for language/vision, user modeling in social media, graph optimization algorithms for summarizing noisy data, computational decipherment and computational advertising. He has published over 30 peer-reviewed papers in top-tier conferences and journals. He was the organizer of the ICML-NAACL symposium in 2013, Conference Workshop Co-Chair for NAACL-HLT 2013 and serves on the PC for ACL, ICML, NIPS, NAACL, EMNLP, AAAI, KDD and WSDM. His work has been reported in several magazines such as New Scientist and ACM TechNews. Homepage: http://www.sravi.org From dcard at andrew.cmu.edu Tue Oct 28 16:20:48 2014 From: dcard at andrew.cmu.edu (Dallas Card) Date: Tue, 28 Oct 2014 16:20:48 -0400 Subject: [CL+NLP Lunch] CL+NLP Lunch, Wei Xu, Monday November 3rd @ 12:00pm Message-ID: <77275ce31adb985072c81c7263bf489c.squirrel@webmail.andrew.cmu.edu> Please join us for the next CL+NLP lunch at noon on Monday November 3rd, where Wei Xu will be speaking about modeling paraphrase. Lunch will be provided! To arrange meetings with Wei on Monday, please contact Dallas Card (dcard at cmu.edu). --- ML+NLP lunch Monday, November 3rd at 12:00pm GHC 6501 Speaker: Wei Xu, University of Pennsylvania TITLE: Modeling Lexically Divergent Paraphrases in Twitter (and Shakespeare!) ABSTRACT: Paraphrases are alternative linguistic expressions of the same meaning. Identifying paraphrases is fundamental to many natural language processing tasks and has been extensively studied for the standard contemporary English. In this talk I will present MULTIP (Multi-instance Learning Paraphrase Model), a joint word-sentence alignment model suited to identify paraphrases within the noisy user generated texts on Twitter. The model infers latent word-level paraphrase anchors from only sentence level annotations during learning. This is a major departure from previous approaches that rely on lexical or distributional similarities over sentence pairs. By reducing the dependence on word overlap as evidence of paraphrase, our approach identifies more lexically divergent expressions with equivalent meaning. For experiments, we constructed a Twitter Paraphrase Corpus of about 19,000 sentences using a novel and efficient crowdsourcing methodology. Our new approach improves the state-of-the-art performance of a method that combines a latent space model with a feature-based supervised classifier. I will also present findings on paraphrasing between standard English and Shakespearean styles. Joint work with Chris Callison-Burch (UPenn), Bill Dolan (MSR), Alan Ritter (OSU), Yangfeng Ji (GaTech), Colin Cherry (NRC) and Ralph Grishman (NYU). Wei Xu is a postdoc in Computer and Information Science Department at University of Pennsylvania, working with Chris Callison-Burch. Her research focuses on paraphrases, social media and information extraction. She received her PhD in Computer Science from New York University. She is organizing the SemEval-2015 shared task on "Paraphrase and Semantic Similarity in Twitter". During her PhD, she visited University of Washington for two years and interned at Microsoft Research, ETS and Amazon.com. From dcard at andrew.cmu.edu Sun Nov 2 13:33:39 2014 From: dcard at andrew.cmu.edu (Dallas Card) Date: Sun, 2 Nov 2014 13:33:39 -0500 Subject: [CL+NLP Lunch] Reminder: CL+NLP Lunch, Wei Xu, Monday November 3rd @ 12:00pm Message-ID: <769d51634128e04fc13627b30b89991b.squirrel@webmail.andrew.cmu.edu> Please join us for the next CL+NLP lunch at noon on Monday November 3rd, where Wei Xu will be speaking about modeling paraphrase. Lunch will be provided! There are still time slots available to meet with Wei; if interested, please contact Dallas Card (dcard at cmu.edu). --- ML+NLP lunch Monday, November 3rd at 12:00pm GHC 6501 Speaker: Wei Xu, University of Pennsylvania TITLE: Modeling Lexically Divergent Paraphrases in Twitter (and Shakespeare!) ABSTRACT: Paraphrases are alternative linguistic expressions of the same meaning. Identifying paraphrases is fundamental to many natural language processing tasks and has been extensively studied for the standard contemporary English. In this talk I will present MULTIP (Multi-instance Learning Paraphrase Model), a joint word-sentence alignment model suited to identify paraphrases within the noisy user generated texts on Twitter. The model infers latent word-level paraphrase anchors from only sentence level annotations during learning. This is a major departure from previous approaches that rely on lexical or distributional similarities over sentence pairs. By reducing the dependence on word overlap as evidence of paraphrase, our approach identifies more lexically divergent expressions with equivalent meaning. For experiments, we constructed a Twitter Paraphrase Corpus of about 19,000 sentences using a novel and efficient crowdsourcing methodology. Our new approach improves the state-of-the-art performance of a method that combines a latent space model with a feature-based supervised classifier. I will also present findings on paraphrasing between standard English and Shakespearean styles. Joint work with Chris Callison-Burch (UPenn), Bill Dolan (MSR), Alan Ritter (OSU), Yangfeng Ji (GaTech), Colin Cherry (NRC) and Ralph Grishman (NYU). Wei Xu is a postdoc in Computer and Information Science Department at University of Pennsylvania, working with Chris Callison-Burch. Her research focuses on paraphrases, social media and information extraction. She received her PhD in Computer Science from New York University. She is organizing the SemEval-2015 shared task on "Paraphrase and Semantic Similarity in Twitter". During her PhD, she visited University of Washington for two years and interned at Microsoft Research, ETS and Amazon.com.