The following papers are available via ftp from the Machine Learning Research Group of the University of Wisconsin, Madison. These papers can be retrieved via a WWW browser, such as Mosaic, or by anonymous ftp. The URL for our publications page is: http://www.cs.wisc.edu/~shavlik/publications.html The URL for our group's "home" page is: http://www.cs.wisc.edu/~shavlik/uwml.html The URL for retrieving these papers via anonymous ftp is: ftp://ftp.cs.wisc.edu/machine-learning/shavlik-group/ If your computer cannot uncompress ".Z" files, simply leave off the ".Z" when you request the ftp transfer; our ftp server will then uncompress the file before transmitting it. Email shavlik@cs.wisc.edu if you have any major problems. ------ THESES ------ @mastersthesis{geisler.thesis ,author = "B. Geisler" ,title = "An Empirical Study of Machine Learning Algorithms Applied to Modeling Player Behavior in a 'First Person Shooter' Video Game" ,school = "Department of Computer Sciences, University of Wisconsin-Madison" ,year = "2002" ,filename = "geisler.thesis.pdf geisler.thesis.ps" ,abstract= "Modern video games present many challenging applications for artificial intelligence. Agents must not only appear intelligent but must also be fun to play against. In the video game genre of the first person shooter an agent must mimic all the behaviors of a human soldier in a combat situation. The standard opponent in a 'first person shooter' uses a finite-state machine and a series of hand coded rules. Drawbacks of this system include a high level of predictability of opponents and a large amount of work manually programming each rule. Modern advances in machine learning have enabled agents to accurately learn rules from a set of examples. By sampling data from an expert player we use these machine learning algorithms in a first person shooter. With this system in place, the programmer has less work when hand coding the combat rules and the learned behaviors are often more unpredictable and life-like than any hard-wired finite state machine. This thesis explores several popular machine learning algorithms and shows how these algorithms can be applied to the game. The empirical study includes decision trees, Naïve Bayes classifiers, neural networks, and neural networks trained using boosting and bagging methods. We show that a subset of AI behaviors can be learned by player modeling using machine learning techniques. Under this system we have successfully been able to learn the combat behaviors of an expert player and apply them to an agent in a modified version of the video game Soldier of Fortune 2. The following tasks were learned: speed of acceleration, direction of movement, direction of facing, and jumping. We evaluate both empirically and aesthetically which learner performed the best and make recommendations for the future. We also have created a system which uses these learned behaviors in a finite-state system within the game at real time." } @phdthesis{eliassi-rad.thesis ,author = "T. Eliassi-Rad" ,title = "Building Intelligent Agents that Learn to Retrieve and Extract Information" ,school = "Department of Computer Sciences, University of Wisconsin-Madison" ,year = "2001" ,filename = "eliassi-rad.thesis.pdf eliassi-rad.thesis.ps" ,note = "(Also appears as UW Technical Report CS-TR-01-1431)" ,abstract= "The rapid growth of on-line information has created a surge of interest in tools that are able to retrieve and extract information from on-line documents. In this thesis, I present and evaluate a computer system that rapidly and easily builds instructable and self-adaptive software agents for both the information retrieval (IR) and the information extraction (IE) tasks. My system is called WAWA (short for Wisconsin Adaptive Web Assistant). WAWA interacts with the user and an on-line (textual) environment (e.g., the Web) to build an intelligent agent for retrieving and extracting information. WAWA has two sub-systems: (i) an information retrieval (IR) sub-system, called WAWA-IR; and, (ii) an information extraction (IE) sub-system, called WAWA-IE. WAWA-IR is a general search-engine agent, which can be trained to produce specialized and personalized IR agents. WAWA-IE is a general extractor system, which creates specialized agents that accurately extract pieces of information from documents in the domain of interest. WAWA utilizes a theory-refinement approach to build its intelligent agents. There are four four primary advantages of using such an approach. First, WAWA's agents are able to perform reasonably well initially because they are able to utilize users' prior knowledge. Second, users' prior knowledge does not have to be correct since it is refined through learning. Third, the use of prior knowledge, plus the continual dialog between the user and an agent, decreases the need for a large number of training examples because training is not limited to a binary representation of positive and negative examples. Finally, WAWA provides an appealing middle ground between non-adaptive agent programming languages and systems that solely learn user preferences from training examples. WAWA's agents have performed quite well in empirical studies. WAWA-IR experiments demonstrate the efficacy of incorporating the feedback provided by the Web into the agent's neural networks to improve the evaluation of potential hyperlinks to traverse. WAWA-IE experiments produce results that are competitive with other state-of-art systems. Moreover, they demonstrate that WAWA-IE agents are able to intelligently and efficiently select from the space of possible extractions and solve multi-slot extraction problems." } @phdthesis{allex.thesis ,author = "C. F. Allex" ,title = "Computational Methods for Fast and Accurate DNA Fragment Assembly" ,school = "Department of Computer Sciences, University of Wisconsin-Madison" ,year = "1999" ,filename = "allex.thesis99.ps" ,note = "(Also appears as UW Technical Report CS-TR-99-1406 [out of print])" ,abstract= "As advances in technology result in the production of increasing amounts of DNA sequencing data in decreasing amounts of time, developing computational methods that allow data analysis to keep pace is imperative. In this dissertation, I present methods that improve the speed and accuracy of DNA fragment assembly. One critical characteristic of automatic methods for fragment assembly is that they must be accurate. Currently, to ensure accurate sequences, the data that underlies questionable base calls must be examined by human editors so that the correct base call can be determined. This manual process is both error-prone and time-consuming. Automatic methods that yield high accuracy and few questionable calls can reduce errors and lessen the need for manual inspections. In my work, I developed a method, Trace-Evidence, that automatically produces highly accurate consensus sequences, even with few aligned sequences. Most assembly programs analyze only base calls when determining a consensus sequence. The key to the high accuracy is that I incorporate morphological information about the underlying ABI trace data. This is accomplished through a new representation of traces, Trace-Class, that characterizes the height and shape of traces. The new representation not only yields high accuracy when used in consensus-calling methods, but also produces improved results when used in removing poor-quality data, and when used as inputs for neural networks for consensus determination. The need for fast processing is becoming more important as the size of sequencing projects increases. Almost all existing fragment assembly programs perform pairwise comparisons of reads, resulting in execution times proportional to n2, where n is the number of reads. I describe a new algorithm for fragment layout, SLIC, that runs in time proportional to n. SLIC relies on subsequences of bases that occur in overlapping regions of fragment reads. Subsequences that are common to two or more fragment reads are aligned to determine the overall layout of reads. The work I present provides improvements to currently available computational methods for DNA sequencing that can serve as a foundation for further study in developing better solutions to problems in fragment assembly." } @phdthesis{craven.thesis ,author = "M. W. Craven" ,title = "Extracting Comprehensible Models from Trained Neural Networks" ,school = "Department of Computer Sciences, University of Wisconsin-Madison" ,year = "1996" ,filename = "craven.thesis.pdf craven.thesis.ps" ,note = "(Also appears as UW Technical Report CS-TR-96-1326 [out of print])" ,abstract= "Although neural networks have been used to develop highly accurate classifiers in numerous real-world problem domains, the models they learn are notoriously difficult to understand. This thesis investigates the task of extracting comprehensible models from trained neural networks, thereby alleviating this limitation. The primary contribution of the thesis is an algorithm that overcomes the significant limitations of previous methods by taking a novel approach to the task of extracting comprehensible models from trained networks. This algorithm, called TREPAN, views the task as an inductive learning problem. Given a trained network, or any other learned model, TREPAN uses queries to induce a decision tree that approximates the function represented by the model. Unlike previous work in this area, TREPAN is broadly applicable as well as scalable to large networks and problems with high-dimensional input spaces. The thesis presents experiments that evaluate TREPAN by applying it to individual networks and to ensembles of neural networks trained in classification, regression, and reinforcement-learning domains. These experiments demonstrate that TREPAN is able to extract decision trees that are comprehensible, yet maintain high levels of fidelity to their respective networks. In problem domains in which neural networks provide superior predictive accuracy to conventional decision tree algorithms, the trees extracted by TREPAN also exhibit superior accuracy, but are comparable in terms of complexity, to the trees learned directly from the training data. A secondary contribution of this thesis is an algorithm, called BBP, that constructively induces simple neural networks. The motivation underlying this algorithm is similar to that for TREPAN: to learn comprehensible models in problem domains in which neural networks have an especially appropriate inductive bias. The BBP algorithm, which is based on a hypothesis-boosting method, learns perceptrons that have relatively few connections. This algorithm provides an appealing combination of strengths: it provides learnability guarantees for a fairly natural class of target functions; it provides good predictive accuracy in a variety of problem domains; and it constructs syntactically simple models, thereby facilitating human comprehension of what it has learned. These algorithms provide mechanisms for improving the understanding of what a trained neural network has learned." } @phdthesis{opitz.thesis ,author = "D. W. Opitz" ,title = "An Anytime Approach to Connectionist Theory Refinement: Refining the Topologies of Knowledge-Based Neural Networks" ,school = "Department of Computer Sciences, University of Wisconsin-Madison" ,year = "1995" ,filename = "opitz.thesis.ps" ,note = "(Also appears as UW Technical Report CS-TR-95-1281 [out of print])" ,abstract= "Many scientific and industrial problems can be better understood by learning from samples of the task at hand. For this reason, the machine learning and statistics communities devote considerable research effort on generating inductive-learning algorithms that try to learn the true ``concept'' of a task from a set of its examples. Often times, however, one has additional resources readily available, but largely unused, that can improve the concept that these learning algorithms generate. These resources include available computer cycles, as well as prior knowledge describing what is currently known about the domain. Effective utilization of available computer time is important since for most domains an expert is willing to wait for weeks, or even months, if a learning system can produce an improved concept. Using prior knowledge is important since it can contain information not present in the current set of training examples.
In this thesis, I present three ``anytime'' approaches to connectionist theory refinement. Briefly, these approaches start by translating a set of rules describing what is currently known about the domain into a neural network, thus generating a knowledge-based neural network (KNN). My approaches then utilize available computer time to improve this KNN by continually refining its weights and topology. My first method, TopGen, searches for good ``local'' refinements to the KNN topology. It does this by adding nodes to the KNN in a manner analogous to symbolically adding rules and conjuncts to an incorrect rule base. My next approach, REGENT, uses genetic algorithms to find better ``global'' changes to this topology. REGENT proceeds by using (a) the domain-specific rules to help create the initial population of KNNs and (b) crossover and mutation operators specifically designed for KNNs. My final algorithm, ADDEMUP, searches for an ``ensemble'' of KNNs that work together to produce an effective composite prediction. ADDEMUP works by using genetic algorithms to continually create new networks, keeping the set of networks that are as accurate as possible while disagreeing with each other as much as possible. Empirical results show that these algorithms successfully achieve each of their respective goals." } @phdthesis{maclin.thesis ,author = "R. Maclin" ,title = "Learning from Instruction and Experience: Methods for Incorporating Procedural Domain Theories into Knowledge-Based Neural Networks" ,school = "Department of Computer Sciences, University of Wisconsin-Madison" ,year = "1995" ,filename = "maclin.thesis.firsthalf.ps maclin.thesis.secondhalf.ps maclin.thesis.firsthalf.pdf maclin.thesis.secondhalf.pdf" ,note = "(Also appears as UW Technical Report CS-TR-95-1285 [out of print])" ,abstract= "This thesis defines and evaluates two systems that allow a teacher to provide instructions to a machine learner. My systems, FSKBANN and RATLE, expand the language that a teacher may use to provide advice to the learner. In particular, my techniques allow a teacher to give partially correct instructions about procedural tasks - tasks that are solved as sequences of steps. FSKBANN and RATLE allow a computer to learn both from instruction and from experience.
Experiments with these systems on several testbeds demonstrate that they produce learners that successfully use and refine the instructions they are given.
In my initial approach, FSKBANN, the teacher provides instructions as a set of propositional rules organized around one or more finite-state automata (FSAs). FSKBANN maps the knowledge in the rules and FSAs into a recurrent neural network. I used FSKBANN to refine the Chou-Fasman algorithm, a method for solving the secondary-structure prediction problem, a difficult task in molecular biology. FSKBANN produces a refined algorithm that outperforms the original (non-learning) Chou-Fasman algorithm, as well as a standard neural-network approach.
My second system, RATLE, allows a teacher to communicate advice, using statements in a simple programming language, to a connectionist, reinforcement-learning agent. The teacher indicates conditions of the environment and actions the agent should take under those conditions. RATLE allows the teacher to give advice continuously by translating the teacher's statements into additions to the agent's neural network. The RATLE language also includes novel (to the theory-refinement literature) features such as multi-step plans and looping constructs. In experiments with RATLE on two simulated testbeds involving multiple agents, I demonstrate that a RATLE agent receiving advice outperforms both an agent that does not receive advice and an agent that receives instruction, but does not refine it.
My methods provide an appealing approach for learning from both instruction and experience in procedural tasks. This work widens the ``information pipeline'' between humans and machine learners, without requiring that the human provide absolutely correct information to the learner." } @phdthesis{towell.thesis ,author = "G. G. Towell" ,title = "Symbolic Knowledge and Neural Networks: Insertion, Refinement and Extraction" ,school = "Department of Computer Sciences, University of Wisconsin-Madison" ,year = "1991" ,note = "(Also appears as UW Technical Report 1072 [out of print].)" ,filename = "towell.thesis.1-2.ps towell.thesis.3.ps towell.thesis.4-7.ps towell.thesis.app.ps" ,abstract= "Explanation-based and empirical learning are two largely complementary methods of machine learning. These approaches to machine learning both have serious problems which preclude their being a general purpose learning method. However, a ``hybrid'' learning method that combines explanation-based with empirical learning may be able to use the strengths of one learning method to address the weaknesses of the other method. Hence, a system that effectively combines the two approaches to learning can be expected to be superior to either approach in isolation. This thesis describes a hybrid system called KBANN which is shown to be an effective combination of these two learning methods.
KBANN (Knowledge-Based Artificial Neural Networks) is a three-part hybrid learning system built on top of ``neural'' learning techniques. The first part uses a set of approximately-correct rules to determine the structure and initial link weights of an artificial neural network, thereby making the rules accessible for modification by neural learning. The second part of KBANN modifies the resulting network using essentially standard neural learning techniques. The third part of KBANN extracts refined rules from trained networks.
KBANN is evaluated by empirical tests in the domain of molecular biology. Networks created by KBANN are shown to be superior, in terms of their ability to correctly classify unseen examples, to a wide variety of learning systems as well as techniques proposed by experts in the problems investigated. In addition, empirical tests show that KBANN is robust to errors in the initial rules and insensitive to problems resulting from the presence of extraneous input features.
The third part of KBANN, which extracts rules from trained networks, addresses a significant problem in the use of neural networks -- understanding what a neural network learns. Empirical tests of the proposed rule-extraction method show that it simplifies understanding of trained networks by reducing the number of: consequents (hidden units), antecedents (weighted links), and possible antecedent weights. Surprisingly, the extracted rules are often more accurate at classifying examples not seen during training than the trained network from which they came." } @phdthesis{gutstein.thesis ,author = "Eric Gutstein" ,title = "SIFT: A Self-Improving Fractions Tutor" ,school = "Department of Computer Sciences, University of Wisconsin-Madison" ,year = "1993" } ----------------- CONFERENCE PAPERS ----------------- @inproceedings{baiao.ilp03 ,filename = "baiao.ilp03.pdf baiao.ilp03.ps baiao.ilp03.doc" ,author = "F. Baiao, M Mattoso, J. Shavlik, G. Zaverucha" ,title = "Applying Theory Revision to the Design of Distributed Databases" ,booktitle = " Proceedings of the Thirteenth International Conference on Inductive Logic Programming" ,year = "2003" ,address = "Szeged, Hungary" ,abstract = "This work presents the application of theory revision to the design of distributed databases to automatically revise a heuristic-based algorithm (called analysis algorithm) through the use of the FORTE system. The analysis algorithm decides the fragmentation technique to be used in each class of the database and its Prolog implementation is provided as the initial domain theory. Fragmentation schemas with previously known performance, obtained from experimental results on top of an object database benchmark, are provided as the set of examples. We show the effectiveness of our approach in finding better fragmentation schemas with improved performance." } @inproceedings{fung.colt03 ,filename = "fung.colt03.pdf fung.colt03.ps" ,author = "G. Fung, O. Mangasarian and J. Shavlik" ,title = "Knowledge-Based Nonlinear Kernel Classifiers" ,booktitle = "16th Annual Conference on Learning Theory (COLT) and 7th Annual Workshop on Kernel Machines, Proceedings" ,year = "2003" ,address = "Washington, DC" ,abstract = "Prior knowledge in the form of multiple polyhedral sets, each belonging to one of two categories, is introduced into a reformulation of a nonlinear kernel support vector machine (SVM) classifier. The resulting formulation leads to a linear program that can be solved efficiently. This extends, in a rather unobvious fashion, previous work that incorporated similar prior knowledge into a linear SVM classifier. Numerical tests on standard-type test problems, such as exclusive-or prior knowledge sets and a checkerboard with 16 points and prior knowledge instead of the usual 1000 points, show the effectiveness of the proposed approach in generating sharp nonlinear classifiers based mostly or totally on prior knowledge." } @inproceedings{dutra.euro03 ,filename = "dutra.euro03.ps dutra.euro03.pdf" ,author = "I. Dutra, D. Page, V. Santos Costa, J. Shavlik and M. Waddell" ,title = "Toward Automatic Management of Embarrassingly Parallel Applications" ,booktitle = "Proceedings of International Conference on Parallel and Distributed Computing (Euro-Par)" ,year = "2003" ,address = "Klagenfurt, Austria" ,abstract = "Large-scale applications that require executing very large numbers of tasks are only feasible through parallelism. In this work we present a system that automatically handles large numbers of experiments and data in the context of machine learning. Our system controls all experiments, including re-submission of failed jobs and relies on available resource managers to spawn jobs through pools of machines. Our results show that we can manage a very large number of experiments, using a reasonable amount of idle CPU cycles, with very little user intervention." } @inproceedings{fung.nips02 ,filename = "fung.nips02.ps fung.nips02.pdf" ,author = "G. M. Fung, O. L. Mangasarian, and J. W. Shavlik" ,title = "Knowledge-Based Support Vector Machine Classifiers" ,booktitle = "Proceedings of Sixteenth Conference on Neural Information Processing Systems (NIPS)" ,year = "2002" ,address = "Vancouver, Canada" ,abstract = "Prior knowledge in the form of multiple polyhedral sets, each belonging to one of two categories, is introduced into a reformulation of a linear support vector machine classifier. The resulting formulation leads to a linear program that can be solved efficiently. Real world examples, from DNA sequencing and breast cancer prognosis, demonstrate the effectiveness of the proposed method. Numerical results show improvement in the test set accuracy after the incorporation of prior knowledge into ordinary, data-based linear support vector machine classifiers. One experiment also shows that a linear classifier, based solely on prior knowledge, far outperforms the direct application of prior knowledge rules to classify data." } @inproceedings{dutra.ilp02 ,filename = "dutra.ilp02.pdf dutra.ilp02.ps" ,author = "I. de Castro Dutra, D. Page, V. Santos Costa and J. Shavlik" ,title = "An Empirical Evaluation of Bagging in Inductive Logic Programming" ,booktitle = "Proceedings of the Twelfth International Conference on Inductive Logic Programming" ,year = "2002" ,pages = "48--65" ,address = "Sydney, Australia" ,abstract = "Ensembles have proven useful for a variety of applications, with a variety of machine learning approaches. While Quinlan has applied boosting to FOIL, the widely-used approach of bagging has never been employed in ILP. Bagging has the advantage over boosting that the different members of the ensemble can be learned and used in parallel. This advantage is especially important for ILP where run-times often are high. We evaluate bagging on three different application domains using the complete-search ILP system, Aleph. We contrast bagging with an approach where we take advantage of the non-determinism in ILP search, by simply allowing Aleph to run multiple times, each time choosing ``seed'' examples at random." } @inproceedings{shavlik.raid01 ,filename = "shavlik.raid01.pdf" ,author = "J. Shavlik, M. Shavlik and M. Fahland" ,title = "Evaluating Software Sensors for Actively Profiling Windows 2000 Computer Users" ,booktitle = "Presented at the Fourth International Symposium on Recent Advances in Intrusion Detection" ,year = "2001" ,address = "Davis, CA" ,abstract = "We report on a new, on-going intrusion-detection project that empirically investigates the usefulness of ''stealing'' a small amount of CPU cycles (1%), main memory (16MB), and disk memory (100 MB) in order to continually gather and analyze dozens of fine-grained system measurements, such as network traffic, identity of the current programs executing, and the user's typing speed. The underlying scientific hypothesis is that a properly chosen set of measurements can provide a ''fingerprint'' that is unique to each user. Hence, such measurements could serve to help distinguish appropriate use of a given computer from misuse, especially by insiders. " } @inproceedings{eliassi-rad.icml01 ,filename = "eliassi-rad.icml01.pdf eliassi-rad.icml01.ps" ,author = "T. Eliassi-Rad and J. Shavlik" ,title = "A Theory-Refinement Approach to Information Extraction" ,booktitle = "Proceedings of the Eighteenth International Conference on Machine Learning" ,year = "2001" ,address = "Williamstown, MA" ,abstract = "We investigate applying theory refinement to the task of extracting information from text. In theory refinement, partial domain knowledge (which may be incorrect) is given to a supervised learner. The provided knowledge guides the learner in its task, but the learner can refine or even discard this knowledge during training. Our supervised learner is a knowledge-based neural network that initially contains compiled prior knowledge about a particular information extraction (IE) task. The prior knowledge needs to specify the extraction slots for the specific IE task. Our approach uses generate-and-test to address the IE task. In the generation step, we produce candidate extractions by intelligently searching the space of possible extractions. In the test step, we use the trained network to judge each candidate and output those that exceed a system-selected threshold. Experiments on the CMU seminar-announcements and the Yeast subcellular-localization domains demonstrate our approach's value." } @inproceedings{craven.ismb2000 ,filename = "craven-ismb00.pdf craven-ismb00.ps" ,author = "M. Craven, D. Page, J. Shavlik, J. Bockhorst, and J. Glasner" ,title = "Probabilistic Learning Approach to Whole-Genome Operon Prediction" ,booktitle = "Proceedings of the Eighth International Conference on Intelligent Systems for Molecular Biology" ,year = 2000 ,address = "La Jolla, CA" ,abstract = "We present a computational approach to predicting operons in the genomes of prokaryotic organisms. Our approach uses machine learning methods to induce predictive models for this task from a rich variety of data types including sequence data, gene expression data, and functional annotations associated with genes. We use multiple learned models that individually predict promoters, terminators and operons themselves. A key part of our approach is a dynamic programming method that uses our predictions to map every known and putative gene in a given genome into its most probable operon. We evaluate our approach using data from the E. coli K-12 genome." } @inproceedings{craven.icml2000 ,filename = "craven-icml00.pdf craven-icml00.ps" ,author = "M. Craven, D. Page, J. Shavlik, J. Bockhorst, and J. Glasner" ,title = "Using Multiple Levels of Learning and Diverse Evidence Sources to Uncover Coordinately Controlled Genes" ,booktitle = "Proceedings of the Seventeenth International Conference on Machine Learning" ,year = 2000 ,address = "Palo Alto, CA" ,abstract = "Now that the complete genomes of numerous organisms have been determined, a key problem in computational molecular biology is uncovering the relationships that exist among the genes in each organism and the regulatory mechanisms that control their operation. We are developing computational methods for discovering such regulatory mechanisms and relationships. Toward this end, we have developed a machine learning approach to identifying sets of genes that are coordinately controlled in the E. coli genome. A number of factors make this an interesting application for machine learning: (i) there is a rich variety of data types that provide useful evidence for this task, (ii) the overall problem of uncovering regulatory mechanisms can be decomposed in multiple machine learning subtasks operating at different levels of detail, (iii) there are not any known negative training examples, and (iv) some of the features are misleading in their predictiveness." } @inproceedings{goecks.iui2000 ,filename = "goecks-iui2000.doc goecks-iui2000.html" ,author = "J. Goecks and J. Shavlik" ,title = "Learning Users' Interests by Unobtrusively Observing Their Normal Behavior" ,booktitle = "Proceedings of the 2000 International Conference on Intelligent User Interfaces" ,year = 2000 ,address = "New Orleans, LA" ,pages = "129-132" ,abstract = "For intelligent interfaces attempting to learn a user's interests, the cost of obtaining labeled training instances is prohibitive because the user must directly label each training instance, and few users are willing to do so. We present an approach that circumvents the need for human-labeled pages. Instead, we learn ``surrogate'' tasks where the desired output is easily measured, such as the number of hyperlinks clicked on a page or the amount of scrolling performed. Our assumption is that these outputs will highly correlate with the user's interests. In other words, by unobtrusively ``observing'' the user's behavior we are able to learn functions of value. For example, an intelligent browser could silently observe the user's browsing behavior during the day, then use these training examples to learn such functions and gather, during the middle of the night, pages that are likely to be of interest to the user. Previous work has focused on learning a user profile by passively observing the hyperlinks clicked on and those passed over. We extend this approach by measuring user mouse and scrolling activity in addition to user browsing activity. We present empirical results that demonstrate our agent can accurately predict some easily measured aspects of one's use of his or her browser." } @inproceedings{shavlik.iui99 ,filename = "shavlik.iui99.pdf shavlik.iui99.ps" ,author = "J. Shavlik, S. Calcari, T. Eliassi-Rad, and J. Solock" ,title = "An Instructable, Adaptive Interface for Discovering and Monitoring Information on the World-Wide Web" ,booktitle = "Proceedings of the 1999 International Conference on Intelligent User Interfaces" ,year = 1999 ,address = "Redondo Beach, CA" ,pages = "157 - 160" ,abstract = "We are creating a customizable, intelligent interface to the World-Wide Web that assists a user in locating specific, current, and relevant information. The Wisconsin Adaptive Web Assistant (WAWA) is capable of accepting instructions regarding what type of information the users are seeking and how to go about looking for it. WAWA compiles these instructions into neural networks, which means that the system's behavior can be modified via training examples. Users can create these training examples by rating pages retrieved by WAWA, but more importantly the system uses techniques from reinforcement learning to internally create its own examples (users can also later provide additional instructions). WAWA uses these neural networks to guide its autonomous navigation of the Web, thereby producing an interface to the Web that users periodically instruct and which in the background searches the Web for relevant information, including periodically revisiting pages that change regularly." } @inproceedings{allex.ismb97 ,filename = "allex.ismb97.ps" ,author = "C.F. Allex, S.F. Baldwin, J.W. Shavlik, and F.R. Blattner" ,title = "Increasing Consensus Accuracy in DNA Fragment Assemblies by Incorporating Fluorescent Trace Representations" ,booktitle = "Proceedings, Fifth International Conference on Intelligent Systems for Molecular Biology" ,year = 1997 ,pages = "" ,publisher = "AAAI Press" ,pub_addr = "Menlo Park, CA" ,address = "Halkidiki, Greece" ,abstract = "We present a new method for determining the consensus sequence in DNA fragment assemblies. The new method, Trace-Evidence, directly incorporates aligned ABI trace information into consensus calculations via our previously described representation, Trace-Data Classifications. The new method extracts and sums evidence indicated by the representation to determine consensus calls. Using the Trace-Evidence method results in automatically produced consensus sequences that are more accurate and less ambiguous than those produced with standard majority-voting methods. Additionally, these improvements are achieved with less coverage than required by the standard methods Ð using Trace-Evidence and a coverage of only three, error rates are as low as those with a coverage of over ten sequences." } @inproceedings{allex.ismb96 ,filename = "allex.ismb96.ps" ,author = "C.F. Allex, S.F. Baldwin, J.W. Shavlik, and F.R. Blattner" ,title = "Improving the Quality of Automatic DNA Sequence Assembly using Fluorescent Trace-Data Classifications" ,booktitle = "Proceedings, Fourth International Conference on Intelligent Systems for Molecular Biology" ,year = 1996 ,pages = "3-14" ,publisher = "AAAI Press" ,pub_addr = "Menlo Park, CA" ,address = "St. Louis, MO" ,abstract = "Virtually all large-scale sequencing projects use automatic sequence-assembly programs to aid in the determination of DNA sequences. The computer-generated assemblies require substantial hand-editing to transform them into submissions for GenBank. As the size of sequencing projects increases, it becomes essential to improve the quality of the automated assemblies so that this time-consuming hand-editing may be reduced. Current ABI sequencing technology uses base calls made from fluorescently-labeled DNA fragments run on gels. We present a new representation for the fluorescent trace data associated with individual base calls. This representation can be used before, during, and after fragment assembly to improve the quality of assemblies. We demonstrate one such use -- end-trimming of sub-optimal data -- that results in a significant improvement in the quality of subsequent assemblies." } @inproceedings{cherkauer.kdd96 ,filename = "cherkauer.kdd96.ps" ,author = "K.J. Cherkauer and J.W. Shavlik" ,title = "Growing Simpler Decision Trees to Facilitate Knowledge Discovery" ,booktitle = "Proceedings, Second International Conference on Knowledge Discovery and Data Mining" ,year = 1996 ,pages = "315-318" ,publisher = "AAAI Press" ,pub_addr = "Menlo Park, CA" ,address = "Portland, OR" ,abstract = "When using machine learning techniques for knowledge discovery, output that is comprehensible to a human is as important as predictive accuracy. We introduce a new algorithm, SET-Gen, that improves the comprehensibility of decision trees grown by standard C4.5 without reducing accuracy. It does this by using genetic search to select the set of input features C4.5 is allowed to use to build its tree. We test SET-Gen on a wide variety of real-world datasets and show that SET-Gen trees are significantly smaller and reference significantly fewer features than trees grown by C4.5 without using SET-Gen. Statistical significance tests show that the accuracies of SET-Gen's trees are either not distinguishable from or are more accurate than those of the original C4.5 trees on all ten datasets tested." } @inproceedings{opitz.nips96 ,author = "D. W. Opitz and J. W. Shavlik" ,title = "Generating Accurate and Diverse Members of a Neural-Network Ensemble" ,booktitle = "Advances in Neural Information Processing Systems" ,volume = 8 ,year = 1996 ,publisher = "MIT Press" ,address = "Denver, CO" ,pages = "535-543" ,filename = "opitz.nips96.ps" ,abstract= "Neural-network ensembles have been shown to be very accurate classification techniques. Previous work has shown that an effective ensemble should consist of networks that are not only highly correct, but ones that make their errors on different parts of the input space as well. Most existing techniques, however, only indirectly address the problem of creating such a set of networks. In this paper we present a technique called ADDEMUP that uses genetic algorithms to directly search for an accurate and diverse set of trained networks. ADDEMUP works by first creating an initial population, then uses genetic operators to continually create new networks, keeping the set of networks that are as accurate as possible while disagreeing with each other as much as possible. Experiments on three DNA problems show that ADDEMUP is able to generate a set of trained networks that is more accurate than several existing approaches. Experiments also show that ADDEMUP is able to effectively incorporate prior knowledge, if available, to improve the quality of its ensemble." } Note: see also opitz.mlrgwp95.ps @inproceedings{cherkauer.nips96 ,author = "K. J. Cherkauer and J. W. Shavlik" ,title = "Rapid Quality Estimation of Neural Network Input Representations" ,booktitle = "Advances in Neural Information Processing Systems" ,volume = 8 ,year = 1996 ,pages = "45-51" ,publisher = "MIT Press" ,address = "Denver, CO" ,filename = "cherkauer.nips96.ps" ,abstract= "The choice of an input representation for a neural network can have a profound impact on its accuracy in classifying novel instances. However, neural networks are typically computationally expensive to train, making it difficult to test large numbers of alternative representations. This paper introduces fast quality measures for neural network representations, allowing one to quickly and accurately estimate which of a collection of possible representations for a problem is the best. We show that our measures for ranking representations are more accurate than a previously published measure, based on experiments with three difficult, real-world pattern recognition problems." } Note: see also cherkauer.ijcai-wkshp95.ps @inproceedings{craven.nips96 ,author = "M. W. Craven and J. W. Shavlik" ,title = "Extracting Tree-Structured Representations of Trained Networks" ,booktitle = "Advances in Neural Information Processing Systems" ,volume = 8 ,year = 1996 ,pages = "24-30" ,address = "Denver, CO" ,publisher = "MIT Press" ,filename = "craven.nips96.ps" ,abstract= "A significant limitation of neural networks is that the representations they learn are usually incomprehensible to humans. We present a novel algorithm, TREPAN, for extracting comprehensible, symbolic representations from trained neural networks. Our algorithm uses queries to induce a decision tree that approximates the concept represented by a given network. Our experiments demonstrate that TREPAN is able to produce decision trees that maintain a high level of fidelity to their respective networks, while being comprehensible and accurate. Unlike previous work in this area, our algorithm is both general in its applicability and scales well to large networks and problems with high-dimensional input spaces." } @inproceedings{jackson.nips96 ,author = "J. C. Jackson and M. W. Craven" ,title = "Learning Sparse Perceptrons" ,booktitle = "Advances in Neural Information Processing Systems" ,volume = 8 ,year = 1996 ,pages = "654-662" ,address = "Denver, CO" ,publisher = "MIT Press" ,filename = "jackson.nips96.ps" ,abstract= "We introduce a new algorithm designed to learn sparse perceptrons over input representations which include high-order features. Our algorithm, which is based on a hypothesis-boosting method, is able to PAC-learn a relatively natural class of target concepts. Moreover, the algorithm appears to work well in practice: on a set of three problem domains, the algorithm produces classifiers that utilize small numbers of features yet exhibit good generalization performance. Perhaps most importantly, our algorithm generates concept descriptions that are easy for humans to understand." } @inproceedings{shavlik.icnn96 ,author = "J. W. Shavlik" ,title = "An Overview of Research at Wisconsin on Knowledge-Based Neural Networks" ,booktitle = "Proceedings of the International Conference on Neural Networks" ,year = 1996 ,address = "Washington, DC" ,filename = "shavlik.icnn96.ps" ,pages = "65-69" ,abstract= "Recent research at the University of Wisconsin on knowledge-based neural networks is surveyed. This work has focused on (a) using symbolically represented background knowledge to improve neural-network learning and (b) extracting comprehensible symbolic representations from trained networks. Important open issues are discussed." } @inproceedings{maclin.ijcai95 ,author = "R. Maclin and J. W. Shavlik" ,title = "Combining the Predictions of Multiple Classifiers: Using Competitive Learning to Initialize Neural Networks" ,booktitle = "Proceedings of the Fourteenth International Joint Conference on Artificial Intelligence" ,year = 1995 ,address = "Montreal, Canada" ,filename = "maclin.ijcai95.ps" ,pages = "524-530" ,abstract= "The primary goal of inductive learning is to generalize well - that is, induce a function that accurately produces the correct output for future inputs. Hansen and Salamon showed that, under certain assumptions, combining the predictions of several separately trained neural networks will improve generalization. One of their key assumptions is that the individual networks should be independent in the errors they produce. In the standard way of performing backpropagation this assumption may be violated, because the standard procedure is to initialize network weights in the region of weight space near the origin. This means that backpropagation's gradient-descent search may only reach a small subset of the possible local minima. In this paper we present an approach to initializing neural networks that uses competitive learning to intelligently create networks that are originally located far from the origin of weight space, thereby potentially increasing the set of reachable local minima. We report experiments on two real-world datasets where combinations of networks initialized with our method generalize better than combinations of networks initialized the traditional way." } @inproceedings{craven.ismb95 ,author = "M. W. Craven and R. J. Mural and L. J. Hauser and E. C. Uberbacher" ,title = "Predicting Protein Folding Classes without Overly Relying on Homology" ,booktitle = "Proceedings of the Third International Conference on Intelligent Systems for Molecular Biology" ,year = 1995 ,address = "Cambridge, England" ,publisher = "AAAI Press" ,pages = "98-106" ,filename = "craven.ismb95.ps" } @inproceedings{opitz.mlc94 ,author = "D. W. Opitz and J. W. Shavlik" ,title = "Using Genetic Search to Refine Knowledge-Based Neural Networks" ,booktitle = "Machine Learning: Proceedings of the Eleventh International Conference" ,year = 1994 ,address = "New Brunswick, NJ" ,publisher = "Morgan Kaufmann" ,pages = "208-216" ,filename = "opitz.mlc94.ps" ,abstract= "An ideal inductive-learning algorithm should exploit all available resources, such as computing power and domain-specific knowledge, to improve its ability to generalize. Connectionist theory-refinement systems have proven to be effective at utilizing domain-specific knowledge; however, most are unable to exploit available computing power. This weakness occurs because they lack the ability to refine the topology of the networks they produce, thereby limiting generalization, especially when given impoverished domain theories. We present the REGENT algorithm, which uses genetic algorithms to broaden the type of networks seen during its search. It does this by using (a) the domain theory to help create an initial population and (b) crossover and mutation operators specifically designed for knowledge-based networks. Experiments on three real-world domains indicate that our new algorithm is able to significantly increase generalization compared to a standard connectionist theory-refinement system, as well as our previous algorithm for growing knowledge-based networks." } @inproceedings{craven.mlc94 ,author = "M. W. Craven and J. W. Shavlik" ,title = "Using Sampling and Queries to Extract Rules from Trained Neural Networks" ,booktitle = "Proceedings of the Eleventh International Conference on Machine Learning" ,year = 1994 ,pages = "37-45" ,address = "New Brunswick, NJ" ,filename = "craven.mlc94.ps" ,abstract= "Concepts learned by neural networks are difficult to understand because they are represented using large assemblages of real-valued parameters. One approach to understanding trained neural networks is to extract symbolic rules that describe their classification behavior. There are several existing rule-extraction approaches that operate by searching for such rules. We present a novel method that casts rule extraction not as a search problem, but instead as a learning problem. In addition to learning from training examples, our method exploits the property that networks can be efficiently queried. We describe algorithms for extracting both conjunctive and M-of-N rules, and present experiments that show that our method is more efficient than conventional search-based approaches." } @inproceedings{maclin.aaai94 ,author = "R. Maclin and J. W. Shavlik" ,title = "Incorporating Advice into Agents that Learn from Reinforcements" ,booktitle = "Proceedings of the Twelfth National Conference on Artificial Intelligence" ,year = 1994 ,address = "Seattle, WA" ,pages = "694-699" ,filename = "maclin.aaai94.ps" ,abstract= "Learning from reinforcements is a promising approach for creating intelligent agents. However, reinforcement learning usually requires a large number of training episodes. We present an approach that addresses this shortcoming by allowing a connectionist Q-learner to accept advice given, at any time and in a natural manner, by an external observer. In our approach, the advice-giver watches the learner and occasionally makes suggestions, expressed as instructions in a simple programming language. Based on techniques from knowledge-based neural networks, these programs are inserted directly into the agent's utility function. Subsequent reinforcement learning further integrates and refines the advice. We present empirical evidence that shows our approach leads to statistically-significant gains in expected reward. Importantly, the advice improves the expected reward regardless of the stage of training at which it is given." } @inproceedings{opitz.ijcai93 ,author = "D. W. Opitz and J. W. Shavlik" ,title = "Heuristically Expanding Knowledge-Based Neural Networks" ,booktitle = "Proceedings of the Thirteenth International Joint Conference on Artificial Intelligence" ,year = 1993 ,month = "September" ,address = "Chambery, France" ,pages = "1360-1365" ,filename = "opitz.ijcai93.ps" ,abstract= "Knowledge-based neural networks are networks whose topology is determined by mapping the dependencies of a domain-specific rulebase into a neural network. However, existing network training methods lack the ability to add new rules to the (reformulated) rulebases. Thus, on domain theories that are lacking rules, generalization is poor, and training can corrupt the original rules, even those that were initially correct. We present TOPGEN, an extension to the KBANN algorithm, that heuristically searches for possible expansions of a knowledge-based neural network, guided by the domain theory, the network, and the training data. It does this by dynamically adding hidden nodes to the neural representation of the domain theory, in a manner analogous to adding rules and conjuncts to the symbolic rulebase. Experiments indicate that our method is able to heuristically find effective places to add nodes to the knowledge-base network and verify that new nodes must be added in an intelligent manner." } @inproceedings{craven.ijcai93, author = "M. W. Craven and J. W. Shavlik", title = "Learning to Represent Codons: A Challenge Problem for Constructive Induction", booktitle = "Proceedings of the Thirteenth International Joint Conference on Artificial Intelligence", year = 1993, month = "September", pages = "1319-1324", address = "Chambery, France", filename = "craven.ijcai93.ps" ,abstract= "The ability of an inductive learning system to find a good solution to a given problem is dependent upon the representation used for the features of the problem. Systems that perform constructive induction are able to change their representation by constructing new features. We describe an important, real-world problem - finding genes in DNA - that we believe offers an interesting challenge to constructive-induction researchers. We report experiments that demonstrate that: (1) two different input representations for this task result in significantly different generalization performance for both neural networks and decision trees; and (2) both neural and symbolic methods for constructive induction fail to bridge the gap between these two representations. We believe that this real-world domain provides an interesting challenge problem for constructive induction because the relationship between the two representations is well known, and because the representational shift involved in constructing the better representation is not imposing." } @inproceedings{cherkauer.ismb93, author = "K. J. Cherkauer and J. W. Shavlik", title = "Protein Structure Prediction: Selecting Salient Features From Large Candidate Pools", booktitle = "Proceedings of the First International Conference on Intelligent Systems for Molecular Biology", year = 1993, address = "Bethesda, MD", pages = "74-82", publisher = "AAAI Press", filename = "cherkauer.ismb93.ps" ,abstract= "We introduce a parallel approach, ``DT-Select,'' for selecting features used by inductive learning algorithms to predict protein secondary structure. DT-Select is able to rapidly choose small, nonredundant feature sets from pools containing hundreds of thousands of potentially useful features. It does this by building a decision tree, using features from the pool, that classifies a set of training examples. The features included in the tree provide a compact description of the training data and are thus suitable for use as inputs to other inductive learning algorithms. Empirical experiments in the protein secondary-structure task, in which sets of complex features chosen by DT-Select are used to augment a standard artificial neural network representation, yield surprisingly little performance gain, even though features are selected from very large feature pools. We discuss some possible reasons for this result." } @inproceedings{craven.mlc93, author = "M. W. Craven and J. W. Shavlik", title = "Learning Symbolic Rules Using Artificial Neural Networks", booktitle = "Proceedings of the Tenth International Conference on Machine Learning", year = 1993, address = "Amherst, MA", pages = "73-80", publisher = "Morgan Kaufmann", filename = "craven.mlc93.ps" ,abstract= "A distinct advantage of symbolic learning algorithms over artificial neural networks is that typically the concept representations they form are more easily understood by humans. One approach to understanding the representations formed by neural networks is to extract symbolic rules from trained networks. In this paper we describe and investigate an approach for extracting rules from networks that uses (1) the NofM extraction algorithm, and (2) the network training method of soft weight-sharing. Previously, the NofM algorithm had been successfully applied only to knowledge-based neural networks. Our experiments demonstrate that our extracted rules generalize better than rules learned using the C4.5 system. In addition to being accurate, our extracted rules are also reasonably comprehensible." } @inproceedings{craven.hicss93, author = "M. W. Craven and J. W. Shavlik", title = "Learning to Predict Reading Frames in {{E}. coli} {DNA} Sequences", booktitle = "Proceedings of the 26th Hawaii International Conference on System Sciences", year = 1993, address = "Wailea, HI", publisher = "IEEE Computer Society Press", pages = "773-782", filename = "craven.hicss93.ps" ,abstract= "Two fundamental problems in analyzing DNA sequences are (1) locating the regions of a DNA sequence that encode proteins, and (2) determining the reading frame for each region. We investigate using artificial neural networks (ANNs) to find coding regions, determine reading frames, and detect frameshift errors in E. coli DNA sequences. We describe our adaptation of the approach used by Uberbacher and Mural to identify coding regions in human DNA, and we compare the performance of ANNs to several conventional methods for predicting reading frames. Our experiments demonstrate that ANNs can outperform these conventional approaches." } @inproceedings{towell.aaai92, author = "G. G. Towell and J. W.Shavlik", title = "Using Symbolic Learning to Improve Knowledge-Based Neural Networks", booktitle = "Proceedings of the Tenth National Conference on Artificial Intelligence", pages = "177-182", year = "1992", address = "San Jose, CA", filename = "towell.aaai92.ps" ,abstract= "The previously-reported KBANN system integrates existing knowledge into neural networks by defining the network topology and setting initial link weights. Standard neural learning techniques can then be used to train such networks, thereby refining the information upon which the network is based. However, standard neural learning techniques are reputed to have difficulty training networks with multiple layers of hidden units; KBANN commonly creates such networks. In addition, standard neural learning techniques ignore some of the information contained in the networks created by KBANN. This paper describes a symbolic inductive learning algorithm for training such networks that uses this previously-ignored information and which helps to address the problems of training ``deep'' networks. Empirical evidence shows that this method improves not only learning speed, but also the ability of networks to generalize correctly to testing examples." } @inproceedings{maclin.aaai92, author = "R. Maclin and J. W. Shavlik", title = "Using Knowledge-Based Neural Networks to Improve Algorithms: Refining the Chou-Fasman Algorithm for Protein Folding", booktitle = "Proceedings of the Tenth National Conference on Artificial Intelligence", pages = "165-170", year = "1992", address = "San Jose, CA", filename = "maclin.aaai92.ps" ,abstract= "We describe a method for using machine learning to refine algorithms represented as generalized finite-state automata. The knowledge in an automaton is translated into an artificial neural network, and then refined with backpropagation on a set of examples. Our technique for translating an automaton into a network extends KBANN, a system that translates a set of propositional rules into a corresponding neural network. The extended system, FSKBANN, allows one to refine the large class of algorithms that can be represented as state-based processes. As a test, we use FSKBANN to refine the Chou-Fasman algorithm, a method for predicting how globular proteins fold. Empirical evidence shows the refined algorithm FSKBANN produces is statistically significantly more accurate than both the original Chou-Fasman algorithm and a neural network trained using the standard approach." } @inproceedings{scott.nips4, author = "G. M. Scott and J. W. Shavlik and W. H. Ray", title = "Refining {PID} Controllers using Neural Networks", booktitle = "Advances in Neural Information Processing Systems", year = "1992", volume = "4", pages = "555-562", editor = "J. Moody and S. Hanson and R. Lippmann", address = "Denver, CO", publisher = "Morgan Kaufmann", filename = "scott.nips4.ps" ,abstract= "The KBANN (Knowledge-Based Artificial Neural Networks) approach uses neural networks to refine knowledge that can be written in the form of simple propositional rules. We extend this idea further by presenting the MANNCON (Multivariable Artificial Neural Network Control) algorithm by which the mathematical equations governing a PID (Proportional-Integral-Derivative) controller determine the topology and initial weights of a network, which is further trained using backpropagation. We apply this method to the task of controlling the outflow and temperature of a water tank, producing statistically-significant gains in accuracy over both a standard neural network approach and a non-learning PID controller. Furthermore, using the PID knowledge to initialize the weights of the network produces statistically less variation in testset accuracy when compared to networks initialized with small random numbers." } @inproceedings{towell.nips4, author = "G. G. Towell and J. W. Shavlik", title = "Interpretation of Artificial Neural Networks: Mapping knowledge-based Neural Networks into Rules", booktitle = "Advances in Neural Information Processing Systems", year = 1992, volume = 4, pages = "977-984", editor = "J. Moody and S. Hanson and R. Lippmann", address = "Denver, CO", publisher = "Morgan Kaufmann", filename = "towell.nips4.ps" ,abstract= "We propose and empirically evaluate a method for the extraction of expert-comprehensible rules from trained neural networks. Our method operates in the context of a three-step process for learning that uses rule-based domain knowledge in combination with neural networks. Empirical tests using real-worlds problems from molecular biology show that the rules our method extracts from trained neural networks: closely reproduce the accuracy of the network from which they came, are superior to the rules derived by a learning system that directly refines symbolic rules, and are expert-comprehensible." } Note: see also towell.mlj93 @inproceedings{noordewier.nips3, author = "M. O. Noordewier and G. G. Towell and J. W. Shavlik", title = "Training Knowledge-Based Neural Networks to Recognize Genes in {DNA} Sequences", booktitle = "Advances in Neural Information Processing Systems", year = 1991, pages = "530-536", volume = 3, editor = "R. Lippmann and J. Moody and D. Touretzky", publisher = "Morgan Kaufmann", address = "Denver, CO", filename = "noordewier.nips3.ps" ,abstract= "We describe the application of a hybrid symbolic/connectionist machine learning algorithm to the task of recognizing important genetic sequences. The symbolic portion of the KBANN system utilizes inference rules that provide a roughly-correct method for recognizing a class of DNA sequences known as eukaryotic splice-junctions. We then map this ``domain theory'' into a neural network and provide training examples. Using the samples, the neural network's learning algorithm adjusts the domain theory so that it properly classifies these DNA sequences. Our procedure constitutes a general method for incorporating preexisting knowledge into artificial neural networks. We present an experiment in molecular genetics that demonstrates the value of doing so." } Note: see also towell.aij94 @inproceedings{towell.aaai90, author = "G. G. Towell and J. W. Shavlik and M. O. Noordewier", title = "Refinement of Approximate Domain Theories by Knowledge-Based Neural Networks", booktitle = "Proceedings of the Eighth National Conference on Artificial Intelligence", year = "1990", pages = "861-866", address = "Boston, MA", filename = "towell.aaai90.ps" ,abstract= "Standard algorithms for explanation-based learning require complete and correct knowledge bases. The KBANN system relaxes this constraint through the use of empirical learning methods to refine approximately correct knowledge. This knowledge is used to determine the structure of an artificial neural network and the weights on its links, thereby making the knowledge accessible for modification by neural learning. KBANN is evaluated by empirical tests in the domain of molecular biology. Networks created by KBANN are shown to be superior, in terms of their ability to correctly classify unseen examples, to randomly initialized neural networks, decision trees, ``nearest neighbor'' matching, and standard techniques reported in the biological literature. In addition, KBANN's networks improve the initial knowledge in biologically interesting ways." } Note: see also towell.aij94.ps --------------- WORKSHOP PAPERS --------------- @inproceedings{dimaio.icdm03 ,filename = "dimaio.icdm03.pdf" ,author = "F. Dimaio, J. Shavlik" ,title = "Speeding Up Relational Data Mining by Learning to Estimate Candidate Hypothesis Scores" ,booktitle = "Proceedings of the ICDM Workshop on Foundations and New Directions of Data Mining" ,year = "2003" ,publisher = "" ,pub_addr = "" ,wkshp_date = "Nov 2003" ,conf_date = "Nov 2003" ,address = "Melbourne, Florida, USA" ,workshop = "Foundations and New Directions in Data Mining" ,abstract = "The motivation behind multi-relational data mining is knowledge discovery in relational databases containing multiple related tables. One difficulty relational data mining faces is managing intractably large hypothesis spaces. We attempt to overcome this difficulty by first sampling the hypothesis space. We generate a small set of hypotheses, uniformly sampled from the space of candidate hypotheses, and evaluate this set on actual data. These hypotheses and their corresponding evaluation scores serve as training data in learning an approximate hypothesis evaluator. We use this approximate evaluation to quickly rate potential hypotheses without needing to score them on actual data. We test our approximate clause evaluation algorithm using the popular Inductive Logic Programming (ILP) system Aleph. We use a neural network to approximate the hypothesis-evaluation function. The trained neural network replaces Aleph’s hypothesis evaluation on actual data, scoring potential rules in time independent of the number of examples. Our approximate evaluator can also be used in a heuristic search to help escape local maxima. We test the neural network's ability in learning the hypothesis-evaluation function on four benchmark ILP domains; the neural network is able to accurately approximate the hypothesis-evaluation function." } @inproceedings{dimaio.icml03 ,filename = "dimaio.icml03.pdf" ,author = "F. DiMaio, J. Shavlik, G. Phillips" ,title = "Using Pictorial Structures to Identify Proteins in X-ray Crystallographic Electron Density Maps" ,booktitle = "Working Notes of the ICML Workshop on Machine Learning in Bioinformatics" ,year = "2003" ,publisher = "" ,pub_addr = "" ,wkshp_date = "Aug 2003" ,conf_date = "Aug 2003" ,address = "Washington DC, USA" ,workshop = "Machine Learning in Bioinformatics" ,abstract = "One of the most time-consuming steps in determining a protein's structure via x-ray crystallography is interpretation of the electron density map. This can be viewed as a computer-vision problem, since a density map is simply a three-dimensional image of a protein. However, due to the intractably large space of conformations the protein can adopt, building a protein model to match in the density map is extremely difficult. This paper describes the use of pictorial structures to build a flexible protein model from the protein's amino acid sequence. A pictorial structure is a way of representing an object as a collection of parts connected, pairwise, by deformable springs. Model parameters are learned from training data. Using an efficient algorithm to match the model to the density map, the most probable arrangement of the protein's atoms can be found in a reasonable running time. We test the algorithm is on two different tasks. The first is an amino-acid sidechain-refinement task, in which the location of the protein's backbone is approximately known. The algorithm places the remaining atoms into the region of density quite accurately, placing 72% of atoms within 1.0 Å of their actual location (as determined by a crystallographer). In the second task, a classification task, the algorithm is used to predict the type of amino acid contained in an unknown region of density. In this task, the algorithm is 61% accurate in discriminating between four different amino acids." } @inproceedings{mooney.nsf02 ,filename = "mooney.nsf02.pdf mooney.nsf02.ps" ,author = "R. J. Mooney, P. Melville, L. P. Rupert Tang, J. Shavlik, I. de Castro Dutra, D. Page, V. Santos Costa" ,title = "Relational Data Mining with Inductive Logic Programming for Link Discovery" ,booktitle = "Proceedings of the National Science Foundation Workshop on Next Generation Data Mining" ,year = 2002 ,publisher = "" ,pub_addr = "" ,wkshp_date = "Nov 2002" ,conf_date = "Nov 2002" ,address = "Baltimore, Maryland, USA" ,workshop = "" ,note = "A longer and updated version of this paper appears as a chapter in ``Data Mining: Next Generation Challenges and Future Directions'', H. Kargupta and A. Joshi (eds.), by AAAI/MIT Press" ,abstract = "Link discovery (LD) is an important task in data mining for counter-terrorism and is the focus of DARPA's Evidence Extraction and Link Discovery (EELD) research program. Link discovery concerns the identification of complex relational patterns that indicate potentially threatening activities in large amounts of relational data. Most data-mining methods assume data is in the form of a feature-vector (a single relational table) and cannot handle multi-relational data. Inductive logic programming is a form of relational data mining that discovers rules in first-order logic from multi-relational data. This paper discusses the application of ILP to learning patterns for link discovery." } @inproceedings{goecks.ijcai-wkshp99 ,filename = "goecks_IJCAI_ML_IF_workshop99.pdf" ,author = "J. Goecks and J.W. Shavlik" ,title = "Automatically Labeling Web Pages Based on Normal User Actions" ,booktitle = "Proceedings of the IJCAI-99 Workshop on Machine Learning for Information Filtering" ,year = 1999 ,publisher = "" ,pub_addr = "" ,wkshp_date = "Jul 31--Aug 6, 1999" ,conf_date = "Jul 31--Aug 6, 1999" ,address = "Stockholm, Sweden" ,workshop = "" ,abstract = "For agents attempting to learn a user's interests, the cost of obtaining labeled training instances is prohibitive because the user must directly label each training instance, and few users are willing to do so. We present an approach that circumvents the need for human-labeled pages. Instead, we learn 'surrogate' tasks where the desired output is easily measured, such as the number of hyperlinks clicked on a page or the amount of scrolling performed. Our assumption is that these outputs will highly correlate with the user's interests. In other words, by unobtrusively 'observing' the user's behavior we are able to learn functions of value. For example, an agent could silently observe the user's browser behavior during the day, then use these training examples to learn such functions and gather, during the middle of the night, pages that are likely to be of interest to the user. Previous work has focused on learning a user profile by passively observing the hyperlinks clicked on and those passed over. We extend this approach by measuring user mouse and scrolling activity in addition to user browsing activity. We present empirical results that demonstrate our agent can accurately predict some easily measured aspects of one's use of his or her browser." } @inproceedings{shavlik.aaai-wkshp98 ,filename = "shavlik.aaai-wkshp98.pdf shavlik.aaai-wkshp98.ps" ,author = "J.W. Shavlik and T. Eliassi-Rad" ,title = "Intelligent Agents for Web-Based Tasks: An Advice-Taking Approach" ,booktitle = "Working Notes of the AAAI/ICML-98 Workshop on Learning for Text Categorization" ,year = 1998 ,publisher = "AAAI Press" ,pub_addr = "Menlo Park, CA" ,wkshp_date = "Jul 26--30, 1998" ,conf_date = "Jul 26--30, 1998" ,address = "Madison, WI" ,workshop = "" ,abstract = "We present and evaluate an implemented system with which to rapidly and easily build intelligent software agents for Web-based tasks. Our design is centered around two basic functions: ScoreThisLink and ScoreThisPage. If given highly accurate such functions, standard heuristic search would lead to efficient retrieval of useful information. Our approach allows users to tailor our system's behavior by providing approximate advice about the above functions. This advice is mapped into neural network implementations of the two functions. Subsequent reinforcements from the Web (e.g., dead links) and any ratings of retrieved pages that the user wishes to provide are, respectively, used to refine the link- and page-scoring functions. Hence, our architecture provides an appealing middle ground between non-adaptive agent programming languages and systems that solely learn user preferences from the user's ratings of pages. We describe our internal representation of Web pages, the major predicates in our advice language, how advice is mapped into neural networks, and the mechanisms for refining advice based on subsequent feedback. We also present a case study where we provide some simple advice and specialize our general-purpose system into a ``home-page finder''. An empirical study demonstrates that our approach leads to a more effective home-page finder than that of a leading commercial Web search site." } @inproceedings{shavlik.conald-wkshp98 ,filename = "shavlik.conald-wkshp98.pdf shavlik.conald-wkshp98.ps" ,author = "J.W. Shavlik and T. Eliassi-Rad" ,title = "Building Intelligent Agents for Web-Based Tasks: A Theory-Refinement Approach" ,booktitle = "Presented at the Conf on Automated Learning and Discovery Workshop on Learning from Text and the Web" ,year = 1998 ,publisher = "" ,pub_addr = "" ,wkshp_date = "Jun 11--13, 1998" ,conf_date = "Jun 11--13, 1998" ,address = "Pittsburgh, PA" ,workshop = "" ,abstract = "We present and evaluate an infrastructure with which to rapidly and easily build intelligent software agents for Web-based tasks. Our design is centered around two basic functions: ScoreThisLink and ScoreThisPage. If given highly accurate such functions, standard heuristic search would lead to efficient retrieval of useful information. Our approach allows users to tailor our system's behavior by providing approximate advice about the above functions. This advice is mapped into neural network implementations of the two functions. Subsequent reinforcements from the Web (e.g., dead links) and any ratings of retrieved pages that the user wishes to provide are, respectively, used to refine the link- and page-scoring functions. Hence, our agent architecture provides an appealing middle ground between non-adaptive ``agent'' programming languages and systems that solely learn user preferences from the user's ratings of pages. We present a case study where we provide some simple advice and specialize our general-purpose system into a ``home-page finder''. An empirical study demonstrates that our approach leads to a more effective home-page finder than that of a leading commercial Web search engine." } @inproceedings{cherkauer.aaai-wkshp96 ,filename = "cherkauer.aaai-wkshp96.ps" ,author = "K.J. Cherkauer" ,title = "Human Expert-Level Performance on a Scientific Image Analysis Task by a System Using Combined Artificial Neural Networks" ,booktitle = "Working Notes, Integrating Multiple Learned Models for Improving and Scaling Machine Learning Algorithms Wkshp, 13th Nat Conf on Artificial Intelligence" ,year = 1996 ,pages = "15-21" ,publisher = "AAAI Press" ,pub_addr = "Menlo Park, CA" ,wkshp_date = "Aug 4--5, 1996" ,conf_date = "Aug 4--8, 1996" ,address = "Portland, OR" ,workshop = "" ,abstract = "This paper presents the Plannett system, which combines artificial neural networks to achieve expert-level accuracy on the difficult scientific task of recognizing volcanos in radar images of the surface of the planet Venus. Plannett uses ANNs that vary along two dimensions: the set of input features used to train and the number of hidden units. The ANNs are combined simply by averaging their output activations. When Plannett is used as the classification module of a three-stage image analysis system called JARtool, the end-to-end accuracy (sensitivity and specificity) is as good as that of a human planetary geologist on a four-image test suite. JARtool-Plannett also achieves the best algorithmic accuracy on these images to date." } @inproceedings{craven.ijcai-wkshp95 ,author = "M. W. Craven and J. W. Shavlik" ,title = "Extracting Comprehensible Concept Representations from Trained Neural Networks" ,booktitle = "Presented at the IJCAI Workshop on Comprehensibility in Machine Learning" ,year = 1995 ,address = "Montreal, Quebec, Canada" ,filename = "craven.ijcai-wkshp95.ps" ,workshop = "" ,abstract= "Although they are applicable to a wide array of problems, and have demonstrated good performance on a number of difficult, real-world tasks, neural networks are not usually applied to problems in which comprehensibility of the acquired concepts is important. The concept representations formed by neural networks are hard to understand because they typically involve distributed, nonlinear relationships encoded by a large number of real-valued parameters. To address this limitation, we have been developing algorithms for extracting ``symbolic'' concept representations from trained neural networks. We first discuss why it is important to be able to understand the concept representations formed by neural networks. We then briefly describe our approach and discuss a number of issues pertaining to comprehensibility that have arisen in our work. Finally, we discuss choices that we have made in our research to date, and open research issues that we have not yet addressed." } @inproceedings{cherkauer.ijcai-wkshp95 ,author = "K. J. Cherkauer and J. W. Shavlik" ,title = "Rapidly Estimating the Quality of Input Representations for Neural Networks" ,booktitle = "Working Notes of the IJCAI-95 Workshop on Data Engineering for Inductive Learning, Fourteenth International Joint Conference on Artificial Intelligence" ,year = 1995 ,address = "Montreal, Quebec, Canada" ,filename = "cherkauer.ijcai-wkshp95.ps" ,workshop = "" ,abstract= "The choice of an input representation for machine learning can have a profound impact on the accuracy of the learned model in classifying novel instances. A reliable method of rapidly estimating the value of a representation, independent of the learner, would be a powerful tool in the search for better representations. We introduce a fast representation- quality measure that is more accurate than Rendell and Ragavan's blurring metric in rank ordering input representations for neural networks on two difficult, real-world datasets. This work constitutes a step forward both in representation quality measures and in our understanding of the characteristics that engender good representations." } Note: see also cherkauer.nips96.ps @inproceedings{opitz.isiknh94 ,author = "D. W. Opitz and J. W. Shavlik" ,title = "Genetically Refining Topologies of Knowledge-Based Neural Networks" ,booktitle = "International Symposium on Integrating Knowledge and Neural Heuristics" ,year = 1994 ,address = "Pensacola, FL" ,pages = "57-66" ,filename = "opitz.isiknh94.ps" ,workshop = "" ,abstract= "Traditional approaches to connectionist theory refinement map the dependencies of a domain-specific rulebase into a neural network, then refine these reformulated rules using neural learning. These approaches have proven to be effective at classifying previously unseen examples; however, most of these approaches suffer in that they are unable to refine the topology of the networks they produce. Thus, when given an ``impoverished'' domain theory, they generalize poorly. A recently published improvement to these approaches, the TopGen algorithm, addressed this limitation by heuristically searching expansions to the knowledge-based networks produced by these algorithms. We show, however, that TopGen's search is too restricted. In response, we present the REGENT algorithm, which uses genetic algorithms to broaden the type of networks seen during its search. It does this by using (a) the domain theory to help create an initial population and (b) crossover and mutation operators specifically designed for knowledge-based networks. Experiments on three real-world domains indicate that our new algorithm is able to significantly increase generalization when compared to both TopGen and a standard approach that does not alter its knowledge-based network's topology." } @inproceedings{maclin.mlc91, author = "R. Maclin and J. W. Shavlik", title = "Refining Domain Theories Expressed as Finite-State Automata", booktitle = "Proceedings of the Eighth International Machine Learning Workshop", year = "1991", pages = "524-528", address = "Evanston, IL", publisher = "Morgan Kaufmann", filename = "maclin.mlc91.ps" ,workshop = "" ,abstract= "The KBANN system uses neural networks to refine domain theories. Currently, domain knowledge in KBANN is expressed as non-recursive, propositional rules. We extend KBANN to domain theories expressed as finite-state automata. We apply finite-state KBANN to the task of predicting how proteins fold, producing a small but statistically significant gain in accuracy over both a standard neural network approach and a non-learning algorithm from the biological literature. Our method shows promise at solving this and other real-world problems that can be described in terms of state-dependent decisions." } Note: this work has been superseded by maclin.aaai92 @inproceedings{towell.mlc91, author = "G. G. Towell and M. W. Craven and J. W. Shavlik", title = "Constructive Induction in Knowledge-Based Neural Networks", booktitle = "Proceedings of the Eighth International Machine Learning Workshop", year = 1991, pages = "213-217", address = "Evanston, IL", publisher = "Morgan Kaufmann", filename = "towell.mlc91.ps", workshop = "" ,abstract= "Artificial neural networks have proven to be a successful, general method for inductive learning from examples. However, they have not often been viewed in terms of constructive induction. We describe a method for using a knowledge-based neural network of the kind created by the KBANN algorithm as the basis of a system for constructive induction. After training, we extract two types of rules from a network: modified versions of the rules initially provided to the knowledge-based neural network, and rules which describe newly constructed features. Our experiments show that the extracted rules are more accurate, at classifying novel examples, than the trained network from which the rules are extracted." } Note: this work has been superseded by towell.nips4, towell.mlj93, @inproceedings{shavlik.cbr91, author = "J. W. Shavlik", title = "Finding Genes by Case-Based Reasoning in the Presence of Noisy Case Boundaries", booktitle = "Proceedings of the DARPA Cased-Based Reasoning Workshop", year = "1991", pages = "327-338", publisher = "Morgan Kaufmann", filename = "shavlik.cbr91.ps" ,workshop = "" ,abstract= "Effectively using previous cases requires that a reasoner first match, in some fashion, the current problem against a large library of stored cases. One largely unaddressed task in case-based reasoning is the process of parsing continuous input into discrete cases. If this parsing is not done accurately, the relevant previous cases may not be found and the advantages of case-based problem solving will be lost. Parsing the data into cases is further complicated when the input data is noisy. This paper presents an approach to applying the case-based paradigm in the presence of noisy case boundaries. The approach has been fully implemented and applied in the domain of molecular biology; specifically, a successful case-based approach to gene finding is described. An empirical study demonstrates that the method is robust even with high error rates. This system is being used in conjunction with a Human Genome project in the Wisconsin Department of Genetics that is sequencing the DNA of the bacterium E. coli." } -------------- JOURNAL PAPERS -------------- @article{scott.NeuralComp92, author = "G. Scott and J. Shavlik and W. Ray", title = "Refining PID Controllers using Neural Networks", journal = "Neural Computation", year = "1992", volume = "4", number = "5", pages = "746-757", filename = "scott.NeuralComp92.pdf" ,abstract= "The KBANN (Knowledge-Based Artificial Neural Networks) approach uses neural networks to refine knowledge that can be written in the form of simple propositional rules. We extend this idea further by presenting the MANNCON (Multivariable Artificial Neural Network Control) algorithm by which the mathematical equations governing a PID (Proportional-Integral-Derivative) controller determine the topology and initial weights of a network, which is further trained using backpropagation. We apply this method to the task of controlling the outflow and temperature of a water tank, producing statistically-significant gains in accuracy over both a standard neural network approach and a non-learning PID controller. Furthermore, using the PID knowledge to initialize the weights of the network produces statistically less variation in testset accuracy when compared to networks initialized with small random numbers." } @article{molla.aimag03 ,filename = "molla.aimag03.pdf molla.aimag03.doc" ,author = "M. Molla, M. Waddell, D. Page and J. Shavlik" ,title = "Using Machine Learning to Design and Interpret Gene-Expression Microarrays" ,journal = "AI Magazine" ,note = "(To Appear in the Special Issue on Bioinformatics)" ,year = "2003" ,abstract = "Gene-expression microarrays, commonly called 'gene chips,' make it possible to simultaneously measure the rate at which a cell or tissue is expressing - translating into a protein - each of its thousands of genes. One can use these comprehensive snapshots of biological activity to infer regulatory pathways in cells, identify novel targets for drug design, and improve the diagnosis, prognosis, and treatment planning for those suffering from disease. However, the amount of data this new technology produces is more than one can manually analyze. Hence, the need for automated analysis of microarray data offers an opportunity for machine learning to have a significant impact on biology and medicine. This article describes microarray technology, the data it produces, and the types of machine-learning tasks that naturally arise with this data. It also reviews some of the recent prominent applications of machine learning to gene-chip data, points to related tasks where machine learning may have a further impact on biology and medicine, and describes additional types of interesting data that recent advances in biotechnology allow biomedical researchers to collect." } @article{bockhorst.bio03 ,author = "J. Bockhorst, M. Craven, D. Page, J. Shavlik and J Glasner" ,title = "A Bayesian Network Approach to Operon Prediction" ,journal = "Bioinformatics" ,volume = "19" ,number = "10" ,year = "2003" ,pages = "1227-1235" ,filename = "bockhorst.bio03.pdf bockhorst.bio03.ps" ,abstract = "Motivation: In order to understand transcription regulation in a given prokaryotic genome, it is critical to identify operons, the fundamental units of transcription, in such species. While there are a growing number of organisms whose sequence and gene coordinates are known, by and large their operons are not known. Results: We present a probabilisitic approach to predicting operons using Bayesian networks. Our approach exploits diverse evidence sources such as sequence and expression data. We evaluate our approach on the E. coli K-12 genome where our results indicate we are able to identify over 78% of its operons at a 10% false positive rate. Also, empirical evaluation using a reduced set of data sources suggests that our approach may have significant value for organisms that do not have as rich of evidence sources as E. coli." } @article{eliassi-rad.umuai01 ,author = "T. Eliassi-Rad and J. Shavlik" ,title = "A System for Building Intelligent Agents that Learn to Retrieve and Extract Information" ,journal = "International Journal on User Modeling and User-Adapted Interaction, Special Issue on User Modeling and Intelligent Agents" ,volume = "13" ,number = "1-2" ,year = "2003" ,pages = "35-88" ,filename = "eliassi-rad.umuai01.pdf eliassi-rad.umuai01.ps" ,abstract = "We present a system for rapidly and easily building instructable and self-adaptive software agents that retrieve and extract information. Our Wisconsin Adaptive Web Assistant (WAWA) constructs intelligent agents by accepting user preferences in the form of instructions. These user-provided instructions are compiled into neural networks that are responsible for the adaptive capabilities of an intelligent agent. The agent's neural networks are modified via user-provided and system-constructed training examples. Users can create training examples by rating Web pages (or documents), but more importantly WAWA's agents uses techniques from reinforcement learning to internally create their own examples. Users can also provide additional instruction throughout the life of an agent. Our experimental evaluations on a home-page finder agent and a seminar-announcement extractor agent illustrate the value of using instructable and adaptive agents for retrieving and extracting information." } @article{molla.cbgi02 ,filename = "molla.cbgi02.pdf molla.cbgi02.doc" ,author = "M. Molla, P. Andrae, J, Glasner, F. Blattner and J. Shavlik" ,title = "Interpreting Microarray Expression Data Using Text Annotating the Genes" ,journal = "Information Sciences" ,volume = 146 ,pages = "75-88" ,note = "Also appears in: Proceedings of the 4th Conference on Computational Biology and Genome Informatics, Durham, NC" ,year = "2002" ,abstract = "Microarray expression data is being generated by the gigabyte all over the world with undoubted exponential increases to come. Annotated genomic data is also rapidly pouring into public databases. Our goal is to develop automated ways of combining these two sources of information to produce insight into the operation of cells under various conditions. Our approach is to use machine-learning techniques to identify characteristics of genes that are up-regulated or down-regulated in a particular microarray experiment. We seek models that are (a) accurate, (b) easy to interpret, and (c) stable to small variations in the training data. This paper explores the effectiveness of two standard machine-learning algorithms for this task: Naïve Bayes (based on probability) and PFOIL (based on building rules). Although we do not anticipate using our learned models to predict expression levels of genes, we cast the task in a predictive framework, and evaluate the quality of the models in terms of their predictive power on genes held out from the training. The paper reports on experiments using actual E. coli microarray data, discussing the strengths and weaknesses of the two algorithms and demonstrating the trade-offs between accuracy, comprehensibility, and stability." } @article{tobler.ismb02 ,filename = "tobler.ismb02.pdf tobler.ismb02.doc" ,author = "J. Tobler, M. Molla, E. Nuwaysir, R. Green and J. Shavlik" ,title = "Evaluating Machine Learning Approaches for Aiding Probe Selection for Gene-Expression Arrays" ,journal = "Bioinformatics, Special Issue Based on the Papers Presented at the Tenth International Conference on Intelligent Systems for Molecular Biology (ISMB-02), Edmonton, Canada" ,year = "2002" ,volume = 18 ,pages = "S164-S171" ,abstract = "Motivation:
Microarrays are a fast and cost-effective method of performing thousands of DNA hybridization experiments simultaneously. DNA probes are typically used to measure the expression level of specific genes. Because probes greatly vary in the quality of their hybridizations, choosing good probes is a difficult task. If one could accurately choose probes that are likely to hybridize well, then fewer probes would be needed to represent each gene in a gene-expression microarray, and, hence, more genes could be placed on an array of a given physical size. Our goal is to empirically evaluate how successfully three standard machine-learning algorithms - naïve Bayes, decision trees, and artificial neural networks - can be applied to the task of predicting good probes. Fortunately it is relatively easy to get training examples for such a learning task: place various probes on a gene chip, add a sample where the corresponding genes are highly expressed, and then record how well each probe measures the presence of its corresponding gene. With such training examples, it is possible that an accurate predictor of probe quality can be learned.
Results:
Two of the learning algorithms we investigate - naïve Bayes and neural networks - learn to predict probe quality surprisingly well. For example, in the top ten predicted probes for a given gene not used for training, on average about five rank in the top 2.5% of that gene's hundreds of possible probes. Decision-tree induction and the simple approach of using predicted melting temperature to rank probes perform significantly worse than these two algorithms. The features we use to represent probes are very easily computed and the time taken to score each candidate probe after training is minor. Training the naïve Bayes algorithm takes very little time, and while it takes over 10 times as long to train a neural network, that time is still not very substantial (on the order of a few hours on a desktop workstation). We also report the information contained in the features we use to describe the probes. We find the fraction of cytosine in the probe to be the most informative feature. We also find, not surprisingly, that the nucleotides in the middle of the probes sequence are more informative than those at the ends of the sequence." } @article{allex.bioinformatics ,author = "C.F. Allex, J.W. Shavlik, and F.R. Blattner" ,title = "Neural Network Input Representations that Produce Accurate Consensus Sequences from DNA Fragment Assemblies" ,journal = "Bioinformatics" ,year = 1999 ,filename = "allex.bioinformatics.ps" ,volume = 15 ,pages = "723-728" ,abstract = " Motivation: Given inputs extracted from an aligned column of DNA bases and the underlying Perkin Elmer Applied Biosystems (ABI) fluorescent traces, our goal is to train a neural network to correctly determine the consensus base for the column. Choosing an appropriate network input representation is critical to success in this task. We empirically compare five representations; one uses only base calls and the others include trace information. Results: We attained the most accurate results from networks that incorporate trace information into their input representations. Based on estimates derived from using 10-fold cross-validation, the best network topology produces consensus accuracies ranging from 99.26% to over 99.98% for coverages from two to six aligned sequences. With a coverage of six, it makes only three errors in 20,000 consensus calls. In contrast, the network that only uses base calls in its input representation has over double that error rate - eight errors in 20,000 consensus calls." } @article{opitz.jair97 ,author = "D. W. Opitz and J. W. Shavlik" ,title = "Connectionist Theory Refinement: Genetically Searching the Space of Network Topologies" ,journal = "Journal of Artificial Intelligence Research" ,year = 1997 ,filename = "opitz.jair97.ps" ,volume = 6 ,pages = "177-209" ,abstract= "An algorithm that learns from a set of examples should ideally be able to exploit the available resources of (a) abundant computing power and (b) domain-specific knowledge to improve its ability to generalize. Connectionist theory-refinement systems, which use background knowledge to select a neural network's topology and initial weights, have proven to be effective at exploiting domain- specific knowledge; however, most do not exploit available computing power. This weakness occurs because they lack the ability to refine the topology of the neural networks they produce, thereby limiting generalization, especially when given impoverished domain theories. We present the REGENT algorithm which uses (a) domain-specific knowledge to help create an initial population of knowledge-based neural networks and (b) genetic operators of crossover and mutation (specifically designed for knowledge-based networks) to continually search for better network topologies. Experiments on three real-world domains indicate that our new algorithm is able to significantly increase generalization compared to a standard connectionist theory- refinement system, as well as our previous algorithm for growing knowledge-based networks. " } @article{craven.fgcs97 ,author = "M. W. Craven and J. W. Shavlik" ,title = "Using Neural Networks for Data Mining" ,journal = "Future Generation Computer Systems" ,year = 1997 ,filename = "craven.fgcs97.ps" ,volume = 13 ,pages = "211-229" ,abstract= "Neural networks have been successfully applied in a wide range of supervised and unsupervised learning applications. Neural-network methods are not commonly used for data-mining tasks, however, because they often produce incomprehensible models and require long training times. In this article, we describe neural-network learning algorithms that are able to produce comprehensible models, and that do not require excessive training times. Specifically, we discuss two classes of approaches for data mining with neural networks. The first type of approach, often called rule extraction, involves extracting symbolic models from trained neural networks. The second approach is to directly learn simple, easy-to-understand networks. We argue that, given the current state of the art, neural-network methods deserve a place in the tool boxes of data-mining specialists." } @article{craven.ijns97 ,author = "M. W. Craven and J. W. Shavlik" ,title = "Understanding Time-Series Networks: A Case Study in Rule Extraction" ,journal = "International Journal of Neural Systems" ,year = 1997 ,filename = "craven.ijns97.ps" ,volume = 8 ,pages = "373-384" ,abstract= "A significant limitation of neural networks is that the representations they learn are usually incomprehensible to humans. We have developed an algorithm, called TREPAN, for extracting comprehensible, symbolic representations from trained neural networks. Given a trained network, TREPAN produces a decision tree that approximates the concept represented by the network. In this article, we discuss the application of TREPAN to a neural network trained on a noisy time series task: predicting the Dollar-Mark exchange rate. We present experiments that show that TREPAN is able to extract a decision tree from this network that equals the network in terms of predictive accuracy, yet provides a comprehensible concept representation. Moreover, our experiments indicate that decision trees induced directly from the training data using conventional algorithms do not match the accuracy nor the comprehensibility of the tree extracted by TREPAN." } @article{opitz.consci96 ,author = "D. W. Opitz and J. W. Shavlik" ,title = "Actively Searching for an Effective Neural-Network Ensemble" ,journal = "Connection Science" ,year = 1996 ,volume = 8 ,number = "3/4" ,pages = "337-353" ,filename = "opitz.consci96.ps" ,abstract= " A neural-network ensemble is a very successful technique where the outputs of a set of separately trained neural network are combined to form one unified prediction. An effective ensemble should consist of a set of networks that are not only highly correct, but ones that make their errors on different parts of the input space as well; however, most existing techniques only indirectly address the problem of creating such a set. We present an algorithm called ADDEMUP that uses genetic algorithms to explicitly search for a highly diverse set of accurate trained networks. ADDEMUP works by first creating an initial population, then uses genetic operators to continually create new networks, keeping the set of networks that are highly accurate while disagreeing with each other as much as possible. Experiments on four real-world domains show that ADDEMUP is able to generate a set of trained networks that is more accurate than several existing ensemble approaches. Experiments also show that ADDEMUP is able to effectively incorporate prior knowledge, if available, to improve the quality of its ensemble." } @article{cherkauer.informatica95 ,author = "K. J. Cherkauer" ,title = "Stuffing Mind into Computer: Knowledge and Learning for Intelligent Systems" ,journal = "Informatica" ,year = 1995 ,volume = 19 ,number = 4 ,pages = "501-511" ,month = "Nov" ,filename = "cherkauer.informatica95.ps" ,abstract= "The task of somehow putting mind into a computer is one that has been pursued by artificial intelligence researchers for decades, and though we are getting closer, we have not caught it yet. Mind is an incredibly complex and poorly understood thing, but we should not let this stop us from continuing to strive toward the goal of intelligent computers. Two issues that are essential to this endeavor are knowledge and learning. These form the basis of human intelligence, and most people believe they are fundamental to achieving similar intelligence in computers. This paper explores issues surrounding knowledge acquisition and learning in intelligent artificial systems in light of both current philosophies of mind and the present state of artificial intelligence research. Its scope ranges from the mundane to the (almost) outlandish, with the goal of stimulating serious thought about where we are, where we would like to go, and how to get there in our attempts to render an intelligence in silicon." } @article{maclin.mlj96 ,author = "R. Maclin and J. W. Shavlik" ,title = "Creating Advice-Taking Reinforcement Learners" ,journal = "Machine Learning" ,volume = 22 ,pages = "251-281" ,year = 1996 ,filename = "maclin.mlj96.ps" ,abstract= "Learning from reinforcements is a promising approach for creating intelligent agents. However, reinforcement learning usually requires a large number of training episodes. We present and evaluate a design that addresses this shortcoming by allowing a connectionist Q-learner to accept advice given, at any time and in a natural manner, by an external observer. In our approach, the advice-giver watches the learner and occasionally makes suggestions, expressed as instructions in a simple imperative programming language. Based on techniques from knowledge-based neural networks, we insert these programs directly into the agent's utility function. Subsequent reinforcement learning further integrates and refines the advice. We present empirical evidence that investigates several aspects of our approach and show that, given good advice, a learner can achieve statistically significant gains in expected reward. A second experiment shows that advice improves the expected reward regardless of the stage of training at which it is given, while another study demonstrates that subsequent advice can result in further gains in reward. Finally, we present experimental results that indicate our method is more powerful than a naive technique for making use of advice." } @article{opitz.kbs95 ,author = "D. W. Opitz and J. W. Shavlik" ,title = "Dynamically Adding Symbolically Meaningful Nodes to Knowledge-Based Neural Networks" ,journal = "Knowledge-Based Systems" ,volume = 8 ,number = 6 ,pages = "301-311" ,year = 1995 ,filename = "opitz.kbs95.ps" ,abstract= "Traditional connectionist theory-refinement systems map the dependencies of a domain-specific rule base into a neural network, and then refine this network using neural learning techniques. Most of these systems, however, lack the ability to refine their network's topology and are thus unable to add new rules to the (reformulated) rule base. Therefore, on domain theories that are lacking rules, generalization is poor, and training can corrupt the original rules, even those that were initially correct. We present TopGen, an extension to the KBANN algorithm, that heuristically searches for possible expansions to KBANN's network. TopGen does this by dynamically adding hidden nodes to the neural representation of the domain theory, in a manner analogous to adding rules and conjuncts to the symbolic rule base. Experiments indicate that our method is able to heuristically find effective places to add nodes to the knowledge bases of four real-world problems, as well as an artificial chess domain. The experiments also verify that new nodes must be added in an intelligent manner. Our algorithm showed statistically significant improvements over KBANN in all five domains." } @article{towell.aij94, author = "G. G. Towell and J. W. Shavlik", title = "Knowledge-Based Artificial Neural Networks", journal = "Artificial Intelligence", year = 1994, volume = 70, number = "1/2", pages = "119-165", filename = "towell.aij94.ps" ,abstract= "Explanation-based and empirical learning are two largely complementary methods of machine learning. These approaches both have serious problems which preclude their being a general-purpose learning method. However, a ``hybrid'' learning method that combines explanation-based with empirical learning may be able to use the strengths of one learning method to address the weaknesses of the other, thereby resulting in a system superior to either approach in isolation. KBANN (Knowledge-Based Artificial Neural Networks) is a hybrid learning system built on top of connectionist learning techniques. It maps problem-specific ``domain theories'', represented in propositional logic, into neural networks and then refines this reformulated knowledge using backpropagation. KBANN is evaluated by extensive empirical tests in the domain of molecular biology. Among other results, these tests show that the networks created by KBANN are superior, in terms of their ability to correctly classify unseen examples, to a wide variety of learning systems, as well as techniques proposed by biologists." } @article{towell.mlj93, author = "G. G. Towell and J. W. Shavlik", title = "The Extraction of Refined Rules from Knowledge-Based Neural Networks", journal = "Machine Learning", year = 1993, volume = 13, number = 1, pages = "71-101", filename = "towell.mlj93.ps" ,abstract= "Neural networks, despite their empirically-proven abilities, have been little used for the refinement of existing knowledge because this task requires a three-step process. First, knowledge must be inserted into a neural network. Second, the network must be refined. Third, the refined knowledge must be extracted from the network. We have previously described a method for the first step of this process. Standard neural learning techniques can accomplish the second step. In this paper, we propose and empirically evaluate a method for the final, and possibly most difficult, step. Our method efficiently extracts symbolic rules from trained neural networks. The four major results of empirical tests of this method are that the extracted rules:
(1) closely reproduce the accuracy of the network from which they are extracted;
(2) are superior to the rules produced by methods that directly refine symbolic rules;
(3) are superior to those produced by previous techniques for extracting rules from trained neural networks;
(4) are ``human comprehensible.''
Thus, this method demonstrates that neural networks can be used to effectively refine symbolic knowledge. Moreover, the rule-extraction technique developed herein contributes to the understanding of how symbolic and connectionist approaches to artificial intelligence can be profitably integrated." } @article{craven.aitools92, author = "M. W. Craven and J. W. Shavlik", title = "Visualizing Learning and Computation in Artificial Neural Networks", year = 1992, pages = "399-425", journal = "International Journal on Artificial Intelligence Tools", volume = "1", number = "3", filename = "craven.ijait93.ps" ,abstract= "Scientific visualization is the process of using graphical images to form succinct and lucid representations of numerical data. Visualization has proven to be a useful method for understanding both learning and computation in artificial neural networks. While providing a powerful and general technique for inductive learning, artificial neural networks are difficult to comprehend because they form representations that are encoded by a large number of real-valued parameters. By viewing these parameters pictorially, a better understanding can be gained of how a network maps inputs into outputs. In this article, we survey a number of visualization techniques for understanding the learning and decision-making processes of neural networks. We also describe our work in {\em knowledge-based neural networks} and the visualization techniques we have used to understand these networks. In a knowledge-based neural network, the topology and initial weight values of the network are determined by an approximately-correct set of inference rules. Knowledge-based networks are easier to interpret than conventional networks because of the synergy between visualization methods and the relation of the networks to symbolic rules." } @article{maclin.mlj93 ,author = "R. Maclin and J. W. Shavlik" ,title = "Using Knowledge-based Neural Networks To Improve Algorithms: Refining the {Chou-Fasman} Algorithm for Protein Folding" ,journal = "Machine Learning" ,volume = 11 ,pages = "195-215" ,year = 1993 ,filename = "maclin.mlj93.ps" ,abstract= "This paper describes a connectionist method for refining algorithms represented as generalized finite-state automata. The method translates the rule-like knowledge in an automaton into a corresponding artificial neural network, and then refines the reformulated automaton by applying backpropagation to a set of examples. This technique for translating an automaton into a network extends the KBANN algorithm, a system that translates a set of propositional rules into a corresponding neural network. The extended system, FSKBANN, allows one to refine the large class of algorithms that can be represented as state-based processes. As a test, FSKBANN is used to improve the Chou-Fasman algorithm, a method for predicting how globular proteins fold. Empirical evidence shows that the multistrategy approach of FSKBANN leads to a statistically significantly more accurate solution than both the original Chou-Fasman algorithm and a neural network trained using the standard approach. Extensive statistics report the types of errors made by the Chou-Fasman algorithm, the standard neural network, and by the FSKBANN network." } @article{craven.mlrgwp93, author = "M. W. Craven and J. W. Shavlik", title = "Machine Learning Approaches to Gene Recognition", journal = "IEEE Expert", volume = 9, number = 2, year = "1993", note = "(The on-line file is a variant of the journal article.)", filename = "craven.mlrgwp93.ps" ,abstract= "Currently, a major computational problem in molecular biology is to identify genes in uncharacterized DNA sequences. The variation, complexity, and incompletely-understood nature of genes make it impractical to hand-code algorithms to recognize them. Machine learning methods - which are able to form their own descriptions of genetic concepts - offer a promising approach to this problem. This article surveys machine-learning approaches to identifying genes in DNA. We discuss two broad classes of gene-recognition approaches: search by signal and search by content. For both classes, we define the specific tasks that they address, describe how these tasks have been framed as machine-learning problems, and survey some of the machine-learning algorithms that have been applied to them." } @article{shavlik.tr92, author = "J. W. Shavlik", title = "A Framework for Combining Symbolic and Neural Learning", journal = "Machine Learning", volume = "14", number = "3", year = "1994", pages = "321-331", note = "(The on-line file is an extended version of the journal article.)", filename = "shavlik.tr92.ps" ,abstract= "This article describes an approach to combining symbolic and connectionist approaches to machine learning. A three-stage framework is presented and the research of several groups is reviewed with respect to this framework. The first stage involves the insertion of symbolic knowledge into neural networks, the second addresses the refinement of this prior knowledge in its neural representation, while the third concerns the extraction of the refined symbolic knowledge. Experimental results and open research issues are discussed." } @article{shavlik.ml91 ,author = "J. W. Shavlik, R. J. Mooney and G. G. Towell" ,title = "Symbolic and Neural Network Learning Algorithms: An Experimental Comparison" ,journal = "Machine Learning" ,volume = 6 ,number = 2 ,year = 1991 ,pages = "111-143" ,note = "(No electronic copy of this article is available)" ,filename = "" ,abstract = "" } @article{shavlik.ml90 ,author = "J. W. Shavlik" ,title = "Acquiring Recursive and Iterative Concepts with Explanation-Based Learning" ,journal = "Machine Learning" ,volume = 5 ,number = 1 ,year = 1990 ,pages = "39-70" ,note = "(No electronic copy of this article is available)" ,filename = "" ,abstract = "" } @article{shavlik.ai90 ,author = "J. W. Shavlik, G. F. DeJong" ,title = "Learning in Mathematically-Based Domains: Understanding and Generalizing Obstacle Cancellations" ,journal = "Artificial Intelligence" ,volume = 45 ,number = 1-2 ,year = 1990 ,pages = "1-45" ,note = "(No electronic copy of this article is available)" ,filename = "" ,abstract = "" } ------------- BOOK CHAPTERS ------------- @incollection{mooney.ld02 ,author = "R. J. Mooney, P. Melville, L. R. Tang, J. Shavlik, I. Dutra, D. Page, and V. Costa" ,title = "Relational Data Mining with Inductive Logic Programming for Link Discovery" ,booktitle = "Data Mining: Next Generation Challenges and Future Directions" ,editor = "H. Kargupta and A. Joshi" ,year = 2003 ,filename = "mooney.ld02.pdf mooney.ld02.ps" ,publisher = "AAAI/MIT Press" ,abstract = "Link discovery (LD) is an important task in data mining for counter-terrorism and is the focus of DARPA's Evidence Extraction and Link Discovery (EELD) research program. Link discovery concerns the identification of complex relational patterns that indicate potentially threatening activities in large amounts of relational data. Most data-mining methods assume data is in the form of a feature-vector (a single relational table) and cannot handle multi-relational data. Inductive logic programming is a form of relational data mining that discovers rules in first-order logic from multi-relational data. This paper discusses the application of ILP to learning patterns for link discovery. " } @incollection{eliassi-rad.springer2001 ,author = "T. Eliassi-Rad and J. Shavlik" ,title = "Intelligent Web Agents that Learn to Retrieve and Extract Information" ,booktitle = "Intelligent Exploration of the Web" ,editor = "P.S. Szczepaniak and F. Segovia and J. Kacprzyk and L.A. Zadeh" ,year = 2003 ,pages = "255-274" ,filename = "eliassi-rad.springer2001.pdf eliassi-rad.springer2001.doc" ,publisher = "Springer-Verlag" ,abstract = "We describe systems that use machine learning methods to retrieve and/or extract textual information from the Web. In particular, we present our Wisconsin Adaptive Web Assistant (WAWA), which constructs a Web agent by accepting user preferences in form of instructions and adapting the agent's behavior as it encounters new information. Our approach enables WAWA to rapidly build instructable and self-adaptive Web agents for both the information retrieval (IR) and information extraction (IE) tasks. WAWA uses two neural networks, which provide adaptive capabilities for its agents. User-provided instructions are compiled into these neural networks and are modified via training examples. Users can create these training examples by rating pages that WAWA retrieves, but more importantly our system uses techniques from reinforcement learning to internally create its own examples. Users can also provide additional instruction throughout the life of an agent. Empirical results on several domains show the advantages of our approach." } @incollection{craven.mlrgwp92 ,author = "M. W. Craven and J. W. Shavlik" ,title = "Investigating the Value of a Good Input Representation" ,booktitle = "Computational Learning Theory and Natural Learning Systems, Volume III" ,editor = "T. Petsche and S. Hanson and J. Shavlik" ,year = 1995 ,filename = "craven.mlrgwp92.ps" ,publisher = "{MIT} Press" } @incollection{opitz.clnl95 ,author = "D. W. Opitz and J. W. Shavlik" ,title = "Using Heuristic Search to Expand Knowledge-Based Neural Networks" ,booktitle = "Computational Learning Theory and Natural Learning Systems, Volume III" ,editor = "T. Petsche and S. Hanson and J. Shavlik" ,year = 1995 ,pages = "3-19" ,filename = "opitz.clnl95.ps" ,publisher = "{MIT} Press" } Note: this work has been superseded by opitz.tr94.ps @incollection{maclin.mlrgwp91 ,author = "R. Maclin and J. W. Shavlik" ,title = "Refining Algorithms with Knowledge-Based Neural Networks: Improving the Chou-Fasman Algorithm for Protein Folding" ,booktitle = "Computational Learning Theory and Natural Learning Systems, Volume I" ,editor = "S. Hanson and G. Drastal and R. Rivest" ,year = 1994 ,filename = "maclin.mlrgwp91.ps" ,publisher = "{MIT} Press" } Note: see also maclin.aaai92 @incollection{cherkauer.inbook94, author = "K. J. Cherkauer and J. W. Shavlik", title = "Selecting Salient Features for Machine Learning from Large Candidate Pools through Parallel Decision-Tree Construction", booktitle = "Massively Parallel Artificial Intelligence", editor = "H. Kitano", year = "1994", pages = "102-136", address = "Menlo Park, CA", publisher = "AAAI Press/The MIT Press", filename = "cherkauer.mpai.ps" ,abstract= "The particular representation used to describe training and testing examples can have profound effects on an inductive algorithm's ability to learn. However, the space of possible representations is virtually infinite, so choosing a good representation is not a simple task. This chapter describes a method whereby the selection of a good input representation for classification tasks is automated. This technique, which we call DT-Select (``Decision Tree feature Selection''), builds decision trees, via a fast parallel implementation of ID3 (Quinlan, 1986), which attempt to correctly classify the training data. The internal nodes of the trees are features drawn from very large pools of complex general-purpose and domain-specific constructed features. Thus, the features included in the trees constitute compact and informative sets which can then be used as input representations for other learning algorithms attacking the same problem. We have implemented DT-Select on a parallel message-passing MIMD architecture, the Thinking Machines CM-5, enabling us to select from pools containing several hundred thousand features in reasonable time. We present here some work using this approach to produce augmentations of artificial neural network input representations for the molecular biology problem of predicting protein secondary structures." } @incollection{towell.ml493, author = "G. G. Towell and J. W. Shavlik", title = "Refining Symbolic Knowledge Using Neural Networks", booktitle = "Machine Learning: An Integrated Approach", volume = 4, editor = "R. S. Michalski and G. Tecuci", year = "1993", address = "San Mateo, CA", publisher = "Morgan Kaufmann", filename = "towell.ml4.ps" } ----------------- TECHNICAL REPORTS ----------------- @techreport{fung.tr01 ,author = "G. M. Fung, O. L. Mangasarian, and J. W. Shavlik" ,title = "Knowledge-based Support Vector Machine Classifiers" ,institution = "Data Mining Institute, University of Wisconsin" ,number = "DMI TR 01-09" ,year = "2001" ,note = "(A shorter version of this paper appears in Advances in Neural Information Processing [NIPS], 2002)" ,filename = "fung.tr01.ps fung.tr01.pdf" ,abstract = "Prior knowledge in the form of multiple polyhedral sets, each belonging to one of two categories, is introduced into a reformulation of a linear support vector machine classifier. The resulting formulation leads to a linear program that can be solved efficiently. Real world examples, from DNA sequencing and breast cancer prognosis, demonstrate the effectiveness of the proposed method. Numerical results show improvement in the test set accuracy after the incorporation of prior knowledge into ordinary, data-based linear support vector machine classifiers. One experiment also shows that a linear classifier, based solely on prior knowledge, far outperforms the direct application of prior knowledge rules to classify data." } @techreport{maclin.tr94 ,author = "R. Maclin and J. W. Shavlik" ,title = "Incorporating Advice into Agents that Learn from Reinforcements" ,institution = "Department of Computer Sciences, University of Wisconsin" ,number = "UW TR 1227" ,year = "1994" ,note = "(A shorter version appears in AAAI-94.)" ,filename = "maclin.tr94.ps" ,abstract= "Learning from reinforcements is a promising approach for creating intelligent agents. However, reinforcement learning usually requires a large number of training episodes. We present a system called RATLE that addresses this shortcoming by allowing a connectionist Q-learner to accept advice given, at any time and in a natural manner, by an external observer. In RATLE, the advice-giver watches the learner and occasionally makes suggestions, expressed as instructions in a simple programming language. Based on techniques from knowledge-based neural networks, RATLE inserts these programs directly into the agent's utility function. Subsequent reinforcement learning further integrates and refines the advice. We present empirical evidence that shows our approach leads to statistically-significant gains in expected reward. Importantly, the advice improves the expected reward regardless of the stage of training at which it is given." } -------------- WORKING PAPERS -------------- @techreport{craven.mlrgwp99 ,author = "M. W. Craven and J. W. Shavlik" ,title = "Rule Extraction: Where Do We Go from Here?" ,institution = "Department of Computer Sciences, University of Wisconsin" ,number = "Machine Learning Research Group Working Paper 99-1" ,year = "1999" ,filename = "craven.mlrgwp99.ps" ,abstract = "We argue that despite being an actively researched area for nearly a decade, rule-extraction technology has not made as significant of an impact as it should have. A confluence of trends, however, has made the ability to extract comprehensible descriptions from complex learned models more important now than ever. We argue that rule-extraction methods can have a significant impact in the overlapping data-mining, machine-learning and neural-network communities if research is focused on several commonly overlooked issues. We then briefly describe how we have tried to address these issues in our own work." } @techreport{craven.mlrgwp95 ,author = "M. W. Craven and J. W. Shavlik" ,title = "Extracting Tree-Structured Representations of Trained Networks" ,institution = "Department of Computer Sciences, University of Wisconsin" ,number = "Machine Learning Research Group Working Paper 95-1" ,year = "1995" } Note: this work has been superseded by craven.nips96.ps @techreport{opitz.mlrgwp95, author = "D. W. Opitz and J. W. Shavlik", title = "Generating Accurate and Diverse Members of a Neural-Network Ensemble", institution = "Department of Computer Sciences, University of Wisconsin", number = "Machine Learning Research Group Working Paper 95-2", year = "1995", note = "(A version of this paper appears in {Advances in Neural Information Processing, vol. 8,} 1996)", filename = "opitz.mlrgwp95.ps" ,abstract= "Neural-network ensembles have been shown to be very accurate classification techniques. Previous work has shown that an effective ensemble should consist of networks that are not only highly correct, but ones that make their errors on different parts of the input space as well. Most existing techniques, however, only indirectly address the problem of creating such a set of networks. In this paper we present a technique called ADDEMUP that uses genetic algorithms to directly search for an accurate and diverse set of trained networks. ADDEMUP works by first creating an initial population, then uses genetic operators to continually create new networks, keeping the set of networks that are as accurate as possible while disagreeing with each other as much as possible. Experiments on three DNA problems show that ADDEMUP is able to generate a set of trained networks that is more accurate than several existing approaches. Experiments also show that ADDEMUP is able to effectively incorporate prior knowledge, if available, to improve the quality of its ensemble." } Note: this work has been superseded by opitz.nips96.ps @techreport{cherkauer.mlrgwp95, author = "K. J. Cherkauer and J. W. Shavlik", title = "Rapid Quality Estimation of Neural Network Input Representations", institution = "Department of Computer Sciences, University of Wisconsin", number = "Machine Learning Research Group Working Paper 95-3", year = "1995", note = "(A version of this paper appears in {\em Advances in Neural Information Processing, vol. 8,} 1996)", } Note: this work has been superseded by cherkauer.nips96.ps @techreport{gutstein.mlrgwp92, author = "E. Gutstein", title = "Learning from Students to Improve an Intelligent Tutoring System", institution = "Department of Computer Sciences, University of Wisconsin", number = "Machine Learning Research Group Working Paper 92-3", year = "1992", filename = "gutstein.mlrgwp92.ps" }