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An inference method for the complete inverse of relative subsumption

NEW GENERATION COMPUTING 1999年第1期17卷 99-117页

作者： Yamamoto, A Hokkaido Univ Div Elect & Informat Engn Kita Ku Sapporo Hokkaido 0608628 Japan Hokkaido Univ Meme Media Lab Kita Ku Sapporo Hokkaido 0608628 Japan

We propose in this paper an inference method called Bottom Generalization for inductive logic programming (ILP, for short). We give an inference procedure based on it, and prove that a hypothesis clause H is derived by the procedure from an example E under a background theory B iff H subsumes E relative to B in Plotkin's sense. The theory B can be any clausal theory, and the example E can be any clause which is not implied by B. The derived hypothesis H is a clause, but is not always definite. The result is proved by defining a declarative semantics for arbitrary consistent clausal theories, and showing that SE-resolution, which was originally introduced by Plotkin, gives their complete procedural semantics. We also show that Bottom Generalization is more powerful than both Jung's method based on the V-operator and Saturant Generalization by Rouveirol, but not than Inverse Entailment by Muggleton. At the ILP '97 workshop we called our inference method "Inverse Entailment," but we have renamed it "Bottom Generalization" because we found that it differs from the original definition of Inverse Entailment.

关键词： inductive logic programming bottom generalization relative subsumption Inverse Entailment the V-operator saturant generalization

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Numerical reasoning with an ILP system capable of lazy evaluation and customised search

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JOURNAL OF logic programming 1999年第2-3期40卷 185-213页

作者： Srinivasan, A Camacho, R Univ Oxford Comp Lab Oxford OX1 3QD England CIUP LIACC P-4150 Porto Portugal

Using problem-specific background knowledge, computer programs developed within the framework of inductive logic programming (ILP) have been used to construct restricted first-order logic solutions to scientific problems. However, their approach to the analysis of data with substantial numerical content has been largely limited to constructing clauses that: (a) provide qualitative descriptions ("high", "low" etc.) of the values of response variables;and (b) contain simple inequalities restricting the ranges of predictor variables. This has precluded the application of such techniques to scientific and engineering problems requiring a more sophisticated approach. A number of specialised methods have been suggested to remedy this. In contrast, we have chosen to take advantage of the fact that the existing theoretical framework for ILP places very few restrictions of the nature of the background knowledge. We describe two issues of implementation that make it possible to use background predicates that implement well-established statistical and numerical analysis procedures. Any improvements in analytical sophistication that result are evaluated empirically using artificial and real-life data. Experiments utilising artificial data are concerned with extracting constraints for response variables in the text-book problem of balancing a pole on a cart. They illustrate the use of clausal definitions of arithmetic and trigonometric functions, inequalities, multiple linear regression, and numerical derivatives. A non-trivial problem concerning the prediction of mutagenic activity of nitroaromatic molecules is also examined. In this case, expert chemists have been unable to devise a model for explaining the data. The result demonstrates the combined use by an ILP program of logical and numerical capabilities to achieve an analysis that includes linear modelling, clustering and classification. In all experiments, the predictions obtained compare favourably against benchmarks se

关键词： inductive logic programming numerical reasoning lazy evaluation customised search

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Efficient algorithm for glitch power reduction

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ELECTRONICS LETTERS 1999年第13期35卷 1040-1041页

作者： Kim, S Kim, J Hwang, SY Sogang Univ Dept Comp Sci Seoul 100611 South Korea Sogang Univ Dept Elect Engn Seoul 100611 South Korea

An efficient algorithm is proposed for reducing glitch power dissipation in CMOS logic circuits. The proposed algorithm takes a path balancing approach that is achieved using gate sizing and buffer insertion methods. The gate sizing technique reduces not only glitches but also the effective circuit capacitance. After gate sizing, buffers are inserted into the remaining unbalanced paths which have not been subjected to gate sizing. ILP has been employed to determine the location of inserted buffers. The proposed algorithm has been tested on LGSynth91 benchmark circuits. Experimental results show that 61.5% of glitches are reduced on average.

关键词： circuit CAD capacitance inductive logic programming integrated circuit design Optimisation gate sizing Digital circuit design, modelling and testing glitch power dissipation circuit capacitance reduction CMOS logic circuits CMOS integrated circuits buffer insertion logic circuits glitch power reduction logic and switching circuits Computer-aided circuit analysis and design Computer-aided logic design logic programming Electronic engineering computing Optimisation techniques path balancing ILP circuit optimisation low-power electronics logic CAD

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Learning function-free Horn expressions

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MACHINE LEARNING 1999年第3期37卷 241-275页

作者： Khardon, R Univ Edinburgh Div Informat Edinburgh EH9 3JZ Midlothian Scotland

The problem of learning universally quantified function free first order Horn expressions is studied. Several models of learning from equivalence and membership queries are considered, including the model where interpretations are examples (Learning from Interpretations), the model where clauses are examples (Learning from Entailment), models where extensional or intentional background knowledge is given to the learner (as done in inductive logic programming), and the model where the reasoning performance of the learner rather than identification is of interest (Learning to Reason). We present learning algorithms for all these tasks for the class of universally quantified function free Horn expressions. The algorithms are polynomial in the number of predicate symbols in the language and the number of clauses in the target Horn expression but exponential in the arity of predicates and the number of universally quantified variables. We also provide lower bounds for these tasks by way of characterising the VC-dimension of this class of expressions. The exponential dependence on the number of variables is the main gap between the lower and upper bounds.

关键词： computational learning theory inductive logic programming Horn expressions direct products

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Integrating induction and abduction in logic programming

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INFORMATION SCIENCES 1999年第1期116卷 25-54页

作者： Lamma, E Mello, P Milano, M Riguzzi, F Univ Bologna DEIS I-40136 Bologna Italy

We propose an approach for the integration of abduction and induction in logic programming. We define an Abductive Learning Problem as an extended inductive logic programming problem where both the background and target theories are abductive theories and where abductive derivability is used as the coverage relation instead of deductive derivability. The two main benefits of this integration are the possibility of learning in presence of incomplete knowledge and the increased expressive power of the background and target theories. We present the system LAP (Learning Abductive Programs) that is able to solve this extended learning problem and we describe, by means of examples, four different learning tasks that can be performed by the system: learning from incomplete knowledge, learning rules with exceptions, learning from integrity constraints and learning recursive predicates. (C) 1999 Elsevier Science Inc. All rights reserved.

关键词： abductive logic programming inductive logic programming machine learning nonmonotonic reasoning

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The complexity of revising logic programs

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JOURNAL OF logic programming 1999年第2-3期40卷 273-298页

作者： Greiner, R Univ Alberta Dept Comp Sci Edmonton AB T6G 2H1 Canada

A rule-based program will return a set of answers to each query. An impure program, which includes the Prolog cut "!" and "not(.)" operators, can return different answers if its rules are re-ordered. There are also many reasoning systems that return only the first answer found for each query;these first answers, too, depend on the rule order, even in pure rule-based systems. A theory revision algorithm, seeking a revised rule-base whose expected accuracy, over the distribution of queries, is optimal, should therefore consider modifying the order of the rules. This paper first shows that a polynomial number of training "labeled queries" (each a query paired with its correct answer) provides the distribution information necessary to identify the optimal ordering. It then proves, however, that the task of determining which ordering is optimal, once given this distributional information, is intractable even in trivial situations;e.g., even if each query is an atomic literal, we are seeking only a "perfect" theory, and the rule base is propositional. We also prove that this task is not even approximable: Unless P = NP, no polynomial time algorithm can produce an ordering of an n-rule theory whose accuracy is within n(gamma) of optimal, for some gamma > 0. We next prove similar hardness and non-approximatability, results for the related tasks of determining, in these impure contexts, (1) the optimal ordering of the antecedents;(2) the optimal set of new rules to add and (3) the optimal set of existing rules to delete. (C) 1999 Elsevier Science Inc. All rights reserved.

关键词： theory revision inductive logic programming computational complexity and approximatability PAC-learning

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inductive synthesis of recursive logic programs: achievements and prospects

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JOURNAL OF logic programming 1999年第2-3期41卷 141-195页

作者： Flener, P Yilmaz, S Uppsala Univ Dept Informat Sci S-75105 Uppsala Sweden Microsoft Corp Redmond WA 98052 USA

The inductive synthesis of recursive logic programs from incomplete information, such as input/output examples, is a challenging subfield both of inductive logic programming (ILP) acid of the synthesis (in general) of logic programs, from formal specifications. We first overview past and present achievements, focusing on the techniques that were designed specifically for the inductive synthesis of recursive logic programs but also discussing a few general ILP techniques that can also induce non-recursive hypotheses. Then we analyse the prospects of these techniques in this task, investigating their applicability to software engineering as well as to knowledge acquisition and discovery. (C) 1999 Elsevier Science Inc. All rights reserved.

关键词： inductive inference inductive logic programming recursion schemas

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Characteristics of recovery from the euthyroid sick syndrome induced by tumor necrosis factor alpha in cancer patients

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METABOLISM-CLINICAL AND EXPERIMENTAL 1999年第3期48卷 324-329页

作者： Feelders, RA Swaak, AJG Romijn, JA Eggermont, AMM Tielens, ET Vreugdenhil, G Endert, E van Eijk, HG Berghout, A Univ Rotterdam Hosp Dept Internal Med 1 NL-3015 GD Rotterdam Netherlands Erasmus Univ Dept Chem Pathol Rotterdam Netherlands Zuiderziekenhuis Dept Rheumatol Rotterdam Netherlands Zuiderziekenhuis Dept Internal Med Rotterdam Netherlands Netherlands Red Cross Blood Transfus Serv Cent Lab Amsterdam Netherlands Univ Amsterdam Acad Med Ctr Dept Endocrinol & Metab NL-1105 AZ Amsterdam Netherlands Univ Rotterdam Hosp Dr Daniel den Hoed Canc Ctr Dept Surg Oncol Rotterdam Netherlands St Joseph Hosp Dept Internal Med Veldhoven Netherlands

Cytokines have been implicated in the pathogenesis of the euthyroid sick syndrome. Isolated limb perfusion (ILP) with recombinant human tumor necrosis factor alpha (rTNF) and melphalan in patients with melanoma or sarcoma is accompanied by high systemic TNF: levels. We examined the prolonged effects (7 days) of ILP on thyroid hormone metabolism with respect to induction and recovery of the euthyroid sick syndrome in six cancer patients. After ILP, when the limb is reconnected to the systemic circulation, leakage of residual rTNF resulted in systemic peak levels at. 10 minutes postperfusion followed by a parallel increase in plasma interleukin-6 (IL-6) and cortisol, with maximum levels at 4 hours (P < .05). A rapid decrease was observed at 5 minutes for plasma triiodothyronine (T3), reverse T3 (rT3), thyroxine (T4), and thyroxine-binding globulin (TBG) (P < .05), whereas free T4 (FT4) and T3-uptake showed a sharp increase, with peak levels at 5 minutes (P < .05). T3, T4, and TBG levels remained low until 24 hours after ILP. In contrast, rT3 increased above pretreatment values to maximum levels at 24 hours (P < .05), Plasma thyrotropin (TSH) showed an initial decrease at 4 hours postperfusion (P < .05) but exceeded pretreatment values from day 1 to day 7 (by +94% +/- 43% to +155% +/- 66%, P < .05), preceding the recovery of T4 and T3 levels. T3 and rT3 returned to initial values at day 4. T4 and TBG levels recovered at day 2. T4 exceeded basal values at days 5 to 7 (P < .05). It is concluded that ILP with rTNF induces a euthyroid sick syndrome either directly or indirectly through other mediators such as IL-6 or cortisol. The recovery from this euthyroid sick syndrome is, at least in part, TSH-dependent, since the prolonged elevation of TSH values preceded and persisted during the normalization of T3 and the elevation of T4 levels. This biphasic pattern of induction of and recovery from the euthyroid sick syndrome may be a general feature of nonthyroidal disease. The

关键词： Euthyroid Sick Syndromes Melanoma Sarcoma Soft Tissue Neoplasms Tumor Necrosis Factor 功能正常甲状腺病综合征黑色素瘤肉瘤软组织肿瘤肿瘤坏死因子 Thyroxine inductive logic programming Melanoma Euthyroid Sick Syndromes Sarcoma Tumor Necrosis Factor-alpha Thyroxine-Binding Globulin Soft Tissue Neoplasms Triiodothyronine, Reverse Tumor Necrosis Factors

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Discovery of frequent DATALOG patterns

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DATA MINING AND KNOWLEDGE DISCOVERY 1999年第1期3卷 7-36页

作者： Dehaspe, L Toivonen, H Katholieke Univ Leuven Dept Comp Sci B-3001 Heverlee Belgium Univ Helsinki Rolf Nevanlinna Inst FIN-00014 Helsinki Finland Univ Helsinki Dept Comp Sci FIN-00014 Helsinki Finland

Discovery of frequent patterns has been studied in a variety of data mining settings. In its simplest form, known from association rule mining, the task is to discover all frequent itemsets, i.e., all combinations of items that are found in a sufficient number of examples. The fundamental task of association rule and frequent set discovery has been extended in various directions, allowing more useful patterns to be discovered with special purpose algorithms. We present WARMR, a general purpose inductive logic programming algorithm that addresses frequent query discovery: a very general DATALOG formulation of the frequent pattern discovery problem. The motivation for this novel approach is twofold. First, exploratory data mining isi well supported: WARMR offers the flexibility required to experiment with standard and in particular novel settings not supported by special purpose algorithms. Also, application prototypes based on WARMR can be used as benchmarks in the comparison and evaluation of new special purpose algorithms. Second, the unified representation gives insight to the blurred picture of the frequent pattern discovery domain. Within the DATALOG formulation a number of dimensions appear that relink diverged settings. We demonstrate the frequent query approach and its use on two applications, one in alarm analysis, and one in a chemical toxicology domain.

关键词： frequent patterns inductive logic programming DATALOG queries association rules episodes sequential patterns

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Frequent pattern discovery in first-order logic

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AI COMMUNICATIONS 1999年第1-2期12卷 115-117页

作者： Dehaspe, L Katholieke Univ Leuven Dept Comp Sci B-3001 Heverlee Belgium

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