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Tara A. Estlin<br>Ph.D. proposal, Department of Computer Sciences, University of Texasat Austin, 1996. <p><blockquote> Planning systems have become an important tool for automating a widevariety of tasks. Control knowledge guides a planner to find solutionsquickly and is crucial for efficient planning in most domains.Machine learning techniques enable a planning system to automaticallyacquire domain-specific search-control knowledge for differentapplications. Past approaches to learning control information haveusually employed explanation-based learning (EBL) to generate controlrules. Unfortunately, EBL alone often produces overly complex rulesthat actually decrease rather than improve overall planningefficiency. This paper presents a novel learning approach for controlknowledge acquisition that integrates explanation-based learning withtechniques from inductive logic programming. In our learning systemSCOPE, EBL is used to constrain an inductive search for controlheuristics that help a planner choose between competing planrefinements. SCOPE is one of the few systems to address learningcontrol information for newer, partial-order planners. Specifically,this proposal describes how SCOPE learns domain-specific control rulesfor the UCPOP planning algorithm. The resulting system is shown toproduce significant speedup in two different planning domains, and tobe more effective than a pure EBL approach.<p>Future research will be performed in three main areas. First, SCOPE'slearning algorithm will be extended to include additional techniquessuch as constructive induction and rule utility analysis. Second,SCOPE will be more thoroughly tested; several real-world planningdomains have been identified as possible testbeds, and more in-depthcomparisons will be drawn between SCOPE and other competingapproaches. Third, SCOPE will be implemented in a different planningsystem in order to test its portability to other planning algorithms.This work should demonstrate that machine-learning techniques can be apowerful tool in the quest for tractable real-world planning.<p></blockquote><!WA16><a href="file://ftp.cs.utexas.edu/pub/mooney/papers/scope-proposal-96.ps.Z"><!WA17><img align=top src="http://www.cs.utexas.edu/users/ml/paper.xbm"></a><p><! ===========================================================================><a name="wolfie-ml-96.ps.Z"</a><b><li>Lexical Acquisition: A Novel Machine Learning Problem<br></b>Cynthia A. Thompson and Raymond J. Mooney<br>Technical Report, Artificial Intelligence Lab, University of Texas at Austin, 1996. <p><blockquote>This paper defines a new machine learning problem to which standardmachine learning algorithms cannot easily be applied. The problemoccurs in the domain of lexical acquisition. The ambiguous andsynonymous nature of words causes the difficulty of using standardinduction techniques to learn a lexicon. Additionally, negativeexamples are typically unavailable or difficult to construct in thisdomain. One approach to solve the lexical acquisition problem ispresented, along with preliminary experimental results on anartificial corpus. Future work includes extending the algorithm andperforming tests on a more realistic corpus.</blockquote><!WA18><a href="file://ftp.cs.utexas.edu/pub/mooney/papers/wolfie-ml-96.ps.Z"><!WA19><img align=top src="http://www.cs.utexas.edu/users/ml/paper.xbm"></a><p><! ===========================================================================><a name="foidl-ml-96.ps.Z"</a><b><li>Advantages of Decision Lists and Implicit Negative in Inductive LogicProgramming<br></b>Mary Elaine Califf and Raymond J. Mooney<br>Technical Report, Artificial Intelligence Lab, University of Texas at Austin, 1996. <p><blockquote>This paper demonstrates the capabilities of FOIDL, an inductive logicprogramming (ILP) system whose distinguishing characteristics are theability to produce first-order decision lists, the use of an outputcompleteness assumption to provide implicit negative examples, and theuse of intensional background knowledge. The development of FOIDL wasoriginally motivated by the problem of learning to generate the pasttense of English verbs; however, this paper demonstrates its superiorperformance on two different sets of benchmark ILP problems. Tests onthe finite element mesh design problem show that FOIDL's decisionlists enable it to produce better results than all other ILP systemswhose results on this problem have been reported. Tests with a selectionof list-processing problems from Bratko's introductory Prolog text demonstrate that the combination of implicit negatives and intensionality allowFOIDL to learn correct programs from far fewer examples than FOIL.</blockquote><!WA20><a href="file://ftp.cs.utexas.edu/pub/mooney/papers/foidl-ml-96.ps.Z"><!WA21><img align=top src="http://www.cs.utexas.edu/users/ml/paper.xbm"></a><p><! ===========================================================================><a name="contex-acl-96.ps.Z"</a><b><li>Learning Parse Decisions From Examples With Rich Context<br></b>Ulf Hermjakob and Raymond J. Mooney<br>Submitted to the 34th Annual Meeting of the Association for Computational Linguistics (ACL-96).<p><blockquote>We present a knowledge and context-based system for parsing natural languageand evaluate it on sentences from the Wall Street Journal.Applying machine learning techniques, the system uses parse action examplesacquired under supervision to generate a deterministic shift-reduce parserin the form of a decision structure. It relies heavily on context, as encoded in features which describe the morpholgical, syntactical, semantical andother aspects of a given parse state.</blockquote><!WA22><a href="file://ftp.cs.utexas.edu/pub/mooney/papers/contex-acl-96.ps.Z"><!WA23><img align=top src="http://www.cs.utexas.edu/users/ml/paper.xbm"></a><p><! ===========================================================================><a name="banner-wolfie-95.ps.Z"</a><b><li> Corpus-Based Lexical Acquisition For Semantic Parsing <br></b>Cynthia Thompson<br>Ph.D. proposal, Department of Computer Sciences, University of Texasat Austin, 1995. <p><blockquote>Building accurate and efficient natural language processing (NLP)systems is an important and difficult problem. There has beenincreasing interest in automating this process. The lexicon, or themapping from words to meanings, is one component that is typicallydifficult to update and that changes from one domain to the next.Therefore, automating the acquisition of the lexicon is an importanttask in automating the acquisition of NLP systems. This proposaldescribes a system, WOLFIE (WOrd Learning From Interpreted Examples),that learns a lexicon from input consisting of sentences paired withrepresentations of their meanings. Preliminary experimental resultsshow that this system can learn correct and useful mappings. Thecorrectness is evaluated by comparing a known lexicon to one learnedfrom the training input. The usefulness is evaluated by examining theeffect of using the lexicon learned by WOLFIE to assist a parseracquisition system, where previously this lexicon had to behand-built. Future work in the form of extensions to the algorithm,further evaluation, and possible applications is discussed.</blockquote><!WA24><a href="file://ftp.cs.utexas.edu/pub/mooney/papers/wolfie-proposal-95.ps.Z"><!WA25><img align=top src="http://www.cs.utexas.edu/users/ml/paper.xbm"></a><p><! ===========================================================================><a name="banner-proposal-95.ps.Z"</a><b><li> Refinement of Bayesian Networks by Combining Connectionist andSymbolic Techniques <br></b>Sowmya Ramanchandran<br>Ph.D. proposal, Department of Computer Sciences, University of Texasat Austin, 1995. <p><blockquote>Bayesian networks provide a mathematically sound formalism forrepresenting and reasoning with uncertain knowledge and are as suchwidely used. However, acquiring and capturing knowledge in thisframework is difficult. There is a growing interest in formulatingtechniques for learning Bayesian networks inductively. While theproblem of learning a Bayesian network, given complete data, has beenexplored in some depth, the problem of learning networks withunobserved causes is still open. In this proposal, we view thisproblem from the perspective of theory revision and present a novelapproach which adapts techniques developed for revising theories insymbolic and connectionist representations. Thus, we assume that thelearner is given an initial approximate network (usually obtained froma expert). Our technique inductively revises the network to fit thedata better. Our proposed system has two components: one componentrevises the parameters of a Bayesian network of known structure, andthe other component revises the structure of the network. Thecomponent for parameter revision maps the given Bayesian network intoa multi-layer feedforward neural network, with the parameters mappedto weights in the neural network, and uses standard backpropagationtechniques to learn the weights. The structure revision component usesqualitative analysis to suggest revisions to the network when it failsto predict the data accurately. The first component has beenimplemented and we will present results from experiments on real worldclassification problems which show our technique to be effective. Wewill also discuss our proposed structure revision algorithm, our plansfor experiments to evaluate the system, as well as some extensions tothe system.</blockquote><!WA26><a href="file://ftp.cs.utexas.edu/pub/mooney/papers/banner-proposal-95.ps.Z"><!WA27><img align=top src="http://www.cs.utexas.edu/users/ml/paper.xbm"></a><p><! ===========================================================================><a name="assert-jaied-95.ps.Z"</a><b><li> Refinement-Based Student Modeling and Automated Bug Library Construction<br></b>Paul Baffes and Raymond Mooney<br><cite>Journal of Artificial Intelligence in Education</cite>, 7, 1(1996), pp. 75-116.<p><blockquote>A critical component of model-based intelligent tutoring sytems is amechanism for capturing the conceptual state of the student, whichenables the system to tailor its feedback to suit individual strengthsand weaknesses. To be useful such a modeling technique must be<em>practical</em>, in the sense that models are easy to construct, and<em>effective</em>, in the sense that using the model actually impacts studentlearning. This research presents a new student modeling techniquewhich can automatically capture novel student errors using onlycorrect domain knowledge, and can automatically compile trends acrossmultiple student models. This approach has been implemented as acomputer program, ASSERT, using a machine learning technique called<em>theory refinement</em>, which is a method for automatically revising aknowledge base to be consistent with a set of examples. Using aknowledge base that correctly defines a domain and examples of astudent's behavior in that domain, ASSERT models student errors bycollecting any refinements to the correct knowledege base which arenecessary to account for the student's behavior. The efficacy of theapproach has been demonstrated by evaluating ASSERT using 100 studentstested on a classification task covering concepts from an introductorycourse on the C++ programming language. Students who receivedfeedback based on the models automatically generated by ASSERTperformed significantly better on a post test than students whoreceived simple teaching.</blockquote><!WA28><a href="file://ftp.cs.utexas.edu/pub/mooney/papers/assert-jaied-95.ps.Z"><!WA29><img align=top src="http://www.cs.utexas.edu/users/ml/paper.xbm"></a><p><! ===========================================================================><a name="chill-bkchapter-95.ps.Z"</a><b><li>Comparative Results on Using Inductive Logic Programmingfor Corpus-based Parser Construction<br></b>John M. Zelle and Raymond J. Mooney<br><cite>Symbolic, Connectionist, and Statistical Approaches to Learning for NaturalLanguage Processing</cite>, S. Wermter, E. Riloff and G. Scheler, Eds,Spring Verlag, 1996. <p> <blockquote>This paper presents results from recent experiments with CHILL, acorpus-based parser acquisition system. CHILL treats languageacquisition as the learning of search-control rules within a logicprogram. Unlike many current corpus-based approaches that usestatistical learning algorithms, CHILL uses techniques from inductivelogic programming (ILP) to learn relational representations. CHILL isa very flexible system and has been used to learn parsers that producesyntactic parse trees, case-role analyses, and executable databasequeries. The reported experiments compare CHILL's performance to thatof a more naive application of ILP to parser acquisition. The resultsshow that ILP techniques, as employed in CHILL, are a viablealternative to statistical methods and that the control-rule frameworkis fundamental to CHILL's success.</blockquote><!WA30><a href="file://ftp.cs.utexas.edu/pub/mooney/papers/chill-bkchapter-95.ps.Z"><!WA31><img align=top src="http://www.cs.utexas.edu/users/ml/paper.xbm"></a><p><! ===========================================================================><a name="foidl-bkchapter-95.ps.Z"</a><b><li>Learning the Past Tense of English Verbs Using Inductive Logic Programming<br></b>Raymond J. Mooney and Mary Elaine Califf<br><cite>Symbolic, Connectionist, and Statistical Approaches to Learning for NaturalLanguage Processing</cite>, S. Wermter, E. Riloff and G. Scheler, Eds,Spring Verlag, 1996. <p>
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