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cs/0001023
Structured Language Modeling for Speech Recognition
cs.CL
A new language model for speech recognition is presented. The model develops hidden hierarchical syntactic-like structure incrementally and uses it to extract meaningful information from the word history, thus complementing the locality of currently used trigram models. The structured language model (SLM) and its per...
cs/0001024
A Parallel Algorithm for Dilated Contour Extraction from Bilevel Images
cs.CV
We describe a simple, but efficient algorithm for the generation of dilated contours from bilevel images. The initial part of the contour extraction is explained to be a good candidate for parallel computer code generation. The remainder of the algorithm is of linear nature.
cs/0001025
Computational Geometry Column 38
cs.CG cs.CV
Recent results on curve reconstruction are described.
cs/0001027
Pattern Discovery and Computational Mechanics
cs.LG cs.NE
Computational mechanics is a method for discovering, describing and quantifying patterns, using tools from statistical physics. It constructs optimal, minimal models of stochastic processes and their underlying causal structures. These models tell us about the intrinsic computation embedded within a process---how it ...
cs/0002001
Computing large and small stable models
cs.LO cs.AI
In this paper, we focus on the problem of existence and computing of small and large stable models. We show that for every fixed integer k, there is a linear-time algorithm to decide the problem LSM (large stable models problem): does a logic program P have a stable model of size at least |P|-k. In contrast, we show ...
cs/0002002
Uniform semantic treatment of default and autoepistemic logics
cs.AI
We revisit the issue of connections between two leading formalisms in nonmonotonic reasoning: autoepistemic logic and default logic. For each logic we develop a comprehensive semantic framework based on the notion of a belief pair. The set of all belief pairs together with the so called knowledge ordering forms a com...
cs/0002003
On the accuracy and running time of GSAT
cs.AI
Randomized algorithms for deciding satisfiability were shown to be effective in solving problems with thousands of variables. However, these algorithms are not complete. That is, they provide no guarantee that a satisfying assignment, if one exists, will be found. Thus, when studying randomized algorithms, there are ...
cs/0002006
Multiplicative Nonholonomic/Newton -like Algorithm
cs.LG
We construct new algorithms from scratch, which use the fourth order cumulant of stochastic variables for the cost function. The multiplicative updating rule here constructed is natural from the homogeneous nature of the Lie group and has numerous merits for the rigorous treatment of the dynamics. As one consequence,...
cs/0002007
Requirements of Text Processing Lexicons
cs.CL
As text processing systems expand in scope, they will require ever larger lexicons along with a parsing capability for discriminating among many senses of a word. Existing systems do not incorporate such subtleties in meaning for their lexicons. Ordinary dictionaries contain such information, but are largely untapped...
cs/0002009
Syntactic Autonomy: Why There is no Autonomy without Symbols and How Self-Organization Might Evolve Them
cs.AI
Two different types of agency are discussed based on dynamically coherent and incoherent couplings with an environment respectively. I propose that until a private syntax (syntactic autonomy) is discovered by dynamically coherent agents, there are no significant or interesting types of closure or autonomy. When synta...
cs/0002010
Biologically Motivated Distributed Designs for Adaptive Knowledge Management
cs.IR
We discuss how distributed designs that draw from biological network metaphors can largely improve the current state of information retrieval and knowledge management of distributed information systems. In particular, two adaptive recommendation systems named TalkMine and @ApWeb are discussed in more detail. TalkMine...
cs/0002012
On The Closest String and Substring Problems
cs.CE cs.CC
The problem of finding a center string that is `close' to every given string arises and has many applications in computational biology and coding theory. This problem has two versions: the Closest String problem and the Closest Substring problem. Assume that we are given a set of strings ${\cal S}=\{s_1, s_2, ..., s_...
cs/0002013
Computing and Comparing Semantics of Programs in Multi-valued Logics
cs.LO cs.DB
The different semantics that can be assigned to a logic program correspond to different assumptions made concerning the atoms whose logical values cannot be inferred from the rules. Thus, the well founded semantics corresponds to the assumption that every such atom is false, while the Kripke-Kleene semantics correspo...
cs/0002014
Safe cooperative robot dynamics on graphs
cs.RO cs.AI
This paper initiates the use of vector fields to design, optimize, and implement reactive schedules for safe cooperative robot patterns on planar graphs. We consider Automated Guided Vehicles (AGV's) operating upon a predefined network of pathways. In contrast to the case of locally Euclidean configuration spaces, re...
cs/0002015
Genetic Algorithms for Extension Search in Default Logic
cs.AI cs.LO
A default theory can be characterized by its sets of plausible conclusions, called its extensions. But, due to the theoretical complexity of Default Logic (Sigma_2p-complete), the problem of finding such an extension is very difficult if one wants to deal with non trivial knowledge bases. Based on the principle of na...
cs/0002016
SLT-Resolution for the Well-Founded Semantics
cs.AI cs.PL
Global SLS-resolution and SLG-resolution are two representative mechanisms for top-down evaluation of the well-founded semantics of general logic programs. Global SLS-resolution is linear for query evaluation but suffers from infinite loops and redundant computations. In contrast, SLG-resolution resolves infinite loo...
cs/0002017
An Usage Measure Based on Psychophysical Relations
cs.CL
A new word usage measure is proposed. It is based on psychophysical relations and allows to reveal words by its degree of "importance" for making basic dictionaries of sublanguages.
cs/0003001
Making news understandable to computers
cs.IR
Computers and devices are largely unaware of events taking place in the world. This could be changed if news were made available in a computer-understandable form. In this paper we present XML documents called NewsForms that represent the key points of 17 types of news events. We discuss the benefits of computer-unde...
cs/0003003
Prospects for in-depth story understanding by computer
cs.AI cs.CL
While much research on the hard problem of in-depth story understanding by computer was performed starting in the 1970s, interest shifted in the 1990s to information extraction and word sense disambiguation. Now that a degree of success has been achieved on these easier problems, I propose it is time to return to in-...
cs/0003004
A database and lexicon of scripts for ThoughtTreasure
cs.AI cs.CL
Since scripts were proposed in the 1970's as an inferencing mechanism for AI and natural language processing programs, there have been few attempts to build a database of scripts. This paper describes a database and lexicon of scripts that has been added to the ThoughtTreasure commonsense platform. The database provi...
cs/0003005
Don't Trash your Intermediate Results, Cache 'em
cs.DB
In data warehouse and data mart systems, queries often take a long time to execute due to their complex nature. Query response times can be greatly improved by caching final/intermediate results of previous queries, and using them to answer later queries. In this paper we describe a caching system called Exchequer wh...
cs/0003006
Materialized View Selection and Maintenance Using Multi-Query Optimization
cs.DB
Because the presence of views enhances query performance, materialized views are increasingly being supported by commercial database/data warehouse systems. Whenever the data warehouse is updated, the materialized views must also be updated. However, whereas the amount of data entering a warehouse, the query loads, a...
cs/0003007
Computing Circumscriptive Databases by Integer Programming: Revisited (Extended Abstract)
cs.AI cs.LO
In this paper, we consider a method of computing minimal models in circumscription using integer programming in propositional logic and first-order logic with domain closure axioms and unique name axioms. This kind of treatment is very important since this enable to apply various technique developed in operations res...
cs/0003008
Consistency Management of Normal Logic Program by Top-down Abductive Proof Procedure
cs.AI
This paper presents a method of computing a revision of a function-free normal logic program. If an added rule is inconsistent with a program, that is, if it leads to a situation such that no stable model exists for a new program, then deletion and addition of rules are performed to avoid inconsistency. We specify a ...
cs/0003009
Conditional indifference and conditional preservation
cs.AI cs.LO
The idea of preserving conditional beliefs emerged recently as a new paradigm apt to guide the revision of epistemic states. Conditionals are substantially different from propositional beliefs and need specific treatment. In this paper, we present a new approach to conditionals, capturing particularly well their dyna...
cs/0003011
Automatic Belief Revision in SNePS
cs.AI cs.LO
SNePS is a logic- and network- based knowledge representation, reasoning, and acting system, based on a monotonic, paraconsistent, first-order term logic, with compositional intensional semantics. It has an ATMS-style facility for belief contraction, and an acting component, including a well-defined syntax and semant...
cs/0003012
Defeasible Reasoning in OSCAR
cs.AI
This is a system description for the OSCAR defeasible reasoner.
cs/0003013
A flexible framework for defeasible logics
cs.AI cs.LO
Logics for knowledge representation suffer from over-specialization: while each logic may provide an ideal representation formalism for some problems, it is less than optimal for others. A solution to this problem is to choose from several logics and, when necessary, combine the representations. In general, such an a...
cs/0003014
Applying Maxi-adjustment to Adaptive Information Filtering Agents
cs.AI cs.MA
Learning and adaptation is a fundamental property of intelligent agents. In the context of adaptive information filtering, a filtering agent's beliefs about a user's information needs have to be revised regularly with reference to the user's most current information preferences. This learning and adaptation process i...
cs/0003015
On the semantics of merging
cs.AI cs.LO
Intelligent agents are often faced with the problem of trying to merge possibly conflicting pieces of information obtained from different sources into a consistent view of the world. We propose a framework for the modelling of such merging operations with roots in the work of Spohn (1988, 1991). Unlike most approache...
cs/0003016
Abductive and Consistency-Based Diagnosis Revisited: a Modeling Perspective
cs.AI
Diagnostic reasoning has been characterized logically as consistency-based reasoning or abductive reasoning. Previous analyses in the literature have shown, on the one hand, that choosing the (in general more restrictive) abductive definition may be appropriate or not, depending on the content of the knowledge base [...
cs/0003017
The lexicographic closure as a revision process
cs.AI cs.LO
The connections between nonmonotonic reasoning and belief revision are well-known. A central problem in the area of nonmonotonic reasoning is the problem of default entailment, i.e., when should an item of default information representing "if A is true then, normally, B is true" be said to follow from a given set of ...
cs/0003018
Description of GADEL
cs.AI cs.LO
This article describes the first implementation of the GADEL system : a Genetic Algorithm for Default Logic. The goal of GADEL is to compute extensions in Reiter's default logic. It accepts every kind of finite propositional default theories and is based on evolutionary principles of Genetic Algorithms. Its first exp...
cs/0003019
Extending Classical Logic with Inductive Definitions
cs.LO cs.AI
The goal of this paper is to extend classical logic with a generalized notion of inductive definition supporting positive and negative induction, to investigate the properties of this logic, its relationships to other logics in the area of non-monotonic reasoning, logic programming and deductive databases, and to sho...
cs/0003020
ACLP: Integrating Abduction and Constraint Solving
cs.AI
ACLP is a system which combines abductive reasoning and constraint solving by integrating the frameworks of Abductive Logic Programming (ALP) and Constraint Logic Programming (CLP). It forms a general high-level knowledge representation environment for abductive problems in Artificial Intelligence and other areas. In...
cs/0003021
Relevance Sensitive Non-Monotonic Inference on Belief Sequences
cs.AI
We present a method for relevance sensitive non-monotonic inference from belief sequences which incorporates insights pertaining to prioritized inference and relevance sensitive, inconsistency tolerant belief revision. Our model uses a finite, logically open sequence of propositional formulas as a representation fo...
cs/0003022
Hypothetical revision and matter-of-fact supposition
cs.AI cs.CL
The paper studies the notion of supposition encoded in non-Archimedean conditional probability (and revealed in the acceptance of the so-called indicative conditionals). The notion of qualitative change of view that thus arises is axiomatized and compared with standard notions like AGM and UPDATE. Applications in the...
cs/0003023
Probabilistic Default Reasoning with Conditional Constraints
cs.AI
We propose a combination of probabilistic reasoning from conditional constraints with approaches to default reasoning from conditional knowledge bases. In detail, we generalize the notions of Pearl's entailment in system Z, Lehmann's lexicographic entailment, and Geffner's conditional entailment to conditional constr...
cs/0003024
A Compiler for Ordered Logic Programs
cs.AI
This paper describes a system, called PLP, for compiling ordered logic programs into standard logic programs under the answer set semantics. In an ordered logic program, rules are named by unique terms, and preferences among rules are given by a set of dedicated atoms. An ordered logic program is transformed into a s...
cs/0003025
Logic Programming for Describing and Solving Planning Problems
cs.AI cs.LO
A logic programming paradigm which expresses solutions to problems as stable models has recently been promoted as a declarative approach to solving various combinatorial and search problems, including planning problems. In this paradigm, all program rules are considered as constraints and solutions are stable models ...
cs/0003027
SLDNFA-system
cs.AI
The SLDNFA-system results from the LP+ project at the K.U.Leuven, which investigates logics and proof procedures for these logics for declarative knowledge representation. Within this project inductive definition logic (ID-logic) is used as representation logic. Different solvers are being developed for this logic an...
cs/0003028
Logic Programs with Compiled Preferences
cs.AI
We describe an approach for compiling preferences into logic programs under the answer set semantics. An ordered logic program is an extended logic program in which rules are named by unique terms, and in which preferences among rules are given by a set of dedicated atoms. An ordered logic program is transformed into...
cs/0003029
Fuzzy Approaches to Abductive Inference
cs.AI
This paper proposes two kinds of fuzzy abductive inference in the framework of fuzzy rule base. The abductive inference processes described here depend on the semantic of the rule. We distinguish two classes of interpretation of a fuzzy rule, certainty generation rules and possible generation rules. In this paper we ...
cs/0003030
Problem solving in ID-logic with aggregates: some experiments
cs.AI
The goal of the LP+ project at the K.U.Leuven is to design an expressive logic, suitable for declarative knowledge representation, and to develop intelligent systems based on Logic Programming technology for solving computational problems using the declarative specifications. The ID-logic is an integration of typed c...
cs/0003031
Optimal Belief Revision
cs.AI
We propose a new approach to belief revision that provides a way to change knowledge bases with a minimum of effort. We call this way of revising belief states optimal belief revision. Our revision method gives special attention to the fact that most belief revision processes are directed to a specific informational ...
cs/0003032
cc-Golog: Towards More Realistic Logic-Based Robot Controllers
cs.AI
High-level robot controllers in realistic domains typically deal with processes which operate concurrently, change the world continuously, and where the execution of actions is event-driven as in ``charge the batteries as soon as the voltage level is low''. While non-logic-based robot control languages are well suite...
cs/0003033
Smodels: A System for Answer Set Programming
cs.AI
The Smodels system implements the stable model semantics for normal logic programs. It handles a subclass of programs which contain no function symbols and are domain-restricted but supports extensions including built-in functions as well as cardinality and weight constraints. On top of this core engine more involved...
cs/0003034
E-RES: A System for Reasoning about Actions, Events and Observations
cs.AI
E-RES is a system that implements the Language E, a logic for reasoning about narratives of action occurrences and observations. E's semantics is model-theoretic, but this implementation is based on a sound and complete reformulation of E in terms of argumentation, and uses general computational techniques of argumen...
cs/0003035
Declarative Representation of Revision Strategies
cs.AI cs.LO
In this paper we introduce a nonmonotonic framework for belief revision in which reasoning about the reliability of different pieces of information based on meta-knowledge about the information is possible, and where revision strategies can be described declaratively. The approach is based on a Poole-style system for...
cs/0003036
DLV - A System for Declarative Problem Solving
cs.AI cs.LO
DLV is an efficient logic programming and non-monotonic reasoning (LPNMR) system with advanced knowledge representation mechanisms and interfaces to classic relational database systems. Its core language is disjunctive datalog (function-free disjunctive logic programming) under the Answer Set Semantics with integri...
cs/0003037
QUIP - A Tool for Computing Nonmonotonic Reasoning Tasks
cs.AI
In this paper, we outline the prototype of an automated inference tool, called QUIP, which provides a uniform implementation for several nonmonotonic reasoning formalisms. The theoretical basis of QUIP is derived from well-known results about the computational complexity of nonmonotonic logics and exploits a represen...
cs/0003038
A Splitting Set Theorem for Epistemic Specifications
cs.AI
Over the past decade a considerable amount of research has been done to expand logic programming languages to handle incomplete information. One such language is the language of epistemic specifications. As is usual with logic programming languages, the problem of answering queries is intractable in the general case....
cs/0003039
DES: a Challenge Problem for Nonmonotonic Reasoning Systems
cs.AI
The US Data Encryption Standard, DES for short, is put forward as an interesting benchmark problem for nonmonotonic reasoning systems because (i) it provides a set of test cases of industrial relevance which shares features of randomly generated problems and real-world problems, (ii) the representation of DES using n...
cs/0003040
Implementing Integrity Constraints in an Existing Belief Revision System
cs.AI cs.LO
SNePS is a mature knowledge representation, reasoning, and acting system that has long contained a belief revision subsystem, called SNeBR. SNeBR is triggered when an explicit contradiction is introduced into the SNePS belief space, either because of a user's new assertion, or because of a user's query. SNeBR then ma...
cs/0003041
Coherence, Belief Expansion and Bayesian Networks
cs.AI cs.LO
We construct a probabilistic coherence measure for information sets which determines a partial coherence ordering. This measure is applied in constructing a criterion for expanding our beliefs in the face of new information. A number of idealizations are being made which can be relaxed by an appeal to Bayesian Networ...
cs/0003042
Fages' Theorem and Answer Set Programming
cs.AI
We generalize a theorem by Francois Fages that describes the relationship between the completion semantics and the answer set semantics for logic programs with negation as failure. The study of this relationship is important in connection with the emergence of answer set programming. Whenever the two semantics are eq...
cs/0003043
Automatic Classification of Text Databases through Query Probing
cs.DB cs.IR
Many text databases on the web are "hidden" behind search interfaces, and their documents are only accessible through querying. Search engines typically ignore the contents of such search-only databases. Recently, Yahoo-like directories have started to manually organize these databases into categories that users can ...
cs/0003044
On the tractable counting of theory models and its application to belief revision and truth maintenance
cs.AI
We introduced decomposable negation normal form (DNNF) recently as a tractable form of propositional theories, and provided a number of powerful logical operations that can be performed on it in polynomial time. We also presented an algorithm for compiling any conjunctive normal form (CNF) into DNNF and provided a st...
cs/0003046
Linear Tabulated Resolution Based on Prolog Control Strategy
cs.AI cs.LO
Infinite loops and redundant computations are long recognized open problems in Prolog. Two ways have been explored to resolve these problems: loop checking and tabling. Loop checking can cut infinite loops, but it cannot be both sound and complete even for function-free logic programs. Tabling seems to be an effectiv...
cs/0003047
BDD-based reasoning in the fluent calculus - first results
cs.AI
The paper reports on first preliminary results and insights gained in a project aiming at implementing the fluent calculus using methods and techniques based on binary decision diagrams. After reporting on an initial experiment showing promising results we discuss our findings concerning various techniques and heuris...
cs/0003048
PAL: Pertinence Action Language
cs.AI cs.LO
The current document contains a brief description of a system for Reasoning about Actions and Change called PAL (Pertinence Action Language) which makes use of several reasoning properties extracted from a Temporal Expert Systems tool called Medtool.
cs/0003049
Planning with Incomplete Information
cs.AI
Planning is a natural domain of application for frameworks of reasoning about actions and change. In this paper we study how one such framework, the Language E, can form the basis for planning under (possibly) incomplete information. We define two types of plans: weak and safe plans, and propose a planner, called the...
cs/0003050
A tableau methodology for deontic conditional logics
cs.LO cs.AI
In this paper we present a theorem proving methodology for a restricted but significant fragment of the conditional language made up of (boolean combinations of) conditional statements with unnested antecedents. The method is based on the possible world semantics for conditional logics. The KEM label formalism, desig...
cs/0003051
Local Diagnosis
cs.AI
In an earlier work, we have presented operations of belief change which only affect the relevant part of a belief base. In this paper, we propose the application of the same strategy to the problem of model-based diangosis. We first isolate the subset of the system description which is relevant for a given observatio...
cs/0003052
A Consistency-Based Model for Belief Change: Preliminary Report
cs.AI
We present a general, consistency-based framework for belief change. Informally, in revising K by A, we begin with A and incorporate as much of K as consistently possible. Formally, a knowledge base K and sentence A are expressed, via renaming propositions in K, in separate languages. Using a maximization process, we...
cs/0003055
TnT - A Statistical Part-of-Speech Tagger
cs.CL
Trigrams'n'Tags (TnT) is an efficient statistical part-of-speech tagger. Contrary to claims found elsewhere in the literature, we argue that a tagger based on Markov models performs at least as well as other current approaches, including the Maximum Entropy framework. A recent comparison has even shown that TnT perfo...
cs/0003056
A note on the Declarative reading(s) of Logic Programming
cs.LO cs.AI
This paper analyses the declarative readings of logic programming. Logic programming - and negation as failure - has no unique declarative reading. One common view is that logic programming is a logic for default reasoning, a sub-formalism of default logic or autoepistemic logic. In this view, negation as failure is ...
cs/0003057
XNMR: A tool for knowledge bases exploration
cs.LO cs.AI
XNMR is a system designed to explore the results of combining the well-founded semantics system XSB with the stable-models evaluator SMODELS. Its main goal is to work as a tool for fast and interactive exploration of knowledge bases.
cs/0003059
SATEN: An Object-Oriented Web-Based Revision and Extraction Engine
cs.AI
SATEN is an object-oriented web-based extraction and belief revision engine. It runs on any computer via a Java 1.1 enabled browser such as Netscape 4. SATEN performs belief revision based on the AGM approach. The extraction and belief revision reasoning engines operate on a user specified ranking of information. One...
cs/0003060
Message Classification in the Call Center
cs.CL
Customer care in technical domains is increasingly based on e-mail communication, allowing for the reproduction of approved solutions. Identifying the customer's problem is often time-consuming, as the problem space changes if new products are launched. This paper describes a new approach to the classification of e-m...
cs/0003061
dcs: An Implementation of DATALOG with Constraints
cs.AI
Answer-set programming (ASP) has emerged recently as a viable programming paradigm. We describe here an ASP system, DATALOG with constraints or DC, based on non-monotonic logic. Informally, DC theories consist of propositional clauses (constraints) and of Horn rules. The semantics is a simple and natural extension of...
cs/0003065
Image Compression with Iterated Function Systems, Finite Automata and Zerotrees: Grand Unification
cs.CV
Fractal image compression, Culik's image compression and zerotree prediction coding of wavelet image decomposition coefficients succeed only because typical images being compressed possess a significant degree of self-similarity. Besides the common concept, these methods turn out to be even more tightly related, to t...
cs/0003067
Detecting Unsolvable Queries for Definite Logic Programs
cs.LO cs.AI
In solving a query, the SLD proof procedure for definite programs sometimes searches an infinite space for a non existing solution. For example, querying a planner for an unreachable goal state. Such programs motivate the development of methods to prove the absence of a solution. Considering the definite program and ...
cs/0003072
MOO: A Methodology for Online Optimization through Mining the Offline Optimum
cs.DS cs.LG
Ports, warehouses and courier services have to decide online how an arriving task is to be served in order that cost is minimized (or profit maximized). These operators have a wealth of historical data on task assignments; can these data be mined for knowledge or rules that can help the decision-making? MOO is a no...
cs/0003073
Proceedings of the 8th International Workshop on Non-Monotonic Reasoning, NMR'2000
cs.AI cs.LO
The papers gathered in this collection were presented at the 8th International Workshop on Nonmonotonic Reasoning, NMR2000. The series was started by John McCarthy in 1978. The first international NMR workshop was held at Mohonk Mountain House, New Paltz, New York in June, 1984, and was organized by Ray Reiter and Bo...
cs/0003074
A Finite State and Data-Oriented Method for Grapheme to Phoneme Conversion
cs.CL
A finite-state method, based on leftmost longest-match replacement, is presented for segmenting words into graphemes, and for converting graphemes into phonemes. A small set of hand-crafted conversion rules for Dutch achieves a phoneme accuracy of over 93%. The accuracy of the system is further improved by using tran...
cs/0003076
Constraint Programming viewed as Rule-based Programming
cs.AI cs.PL
We study here a natural situation when constraint programming can be entirely reduced to rule-based programming. To this end we explain first how one can compute on constraint satisfaction problems using rules represented by simple first-order formulas. Then we consider constraint satisfaction problems that are based...
cs/0003077
DATALOG with constraints - an answer-set programming system
cs.AI
Answer-set programming (ASP) has emerged recently as a viable programming paradigm well attuned to search problems in AI, constraint satisfaction and combinatorics. Propositional logic is, arguably, the simplest ASP system with an intuitive semantics supporting direct modeling of problem constraints. However, for som...
cs/0003079
Differential Invariants under Gamma Correction
cs.CV
This paper presents invariants under gamma correction and similarity transformations. The invariants are local features based on differentials which are implemented using derivatives of the Gaussian. The use of the proposed invariant representation is shown to yield improved correlation results in a template matching...
cs/0003080
Some Remarks on Boolean Constraint Propagation
cs.AI
We study here the well-known propagation rules for Boolean constraints. First we propose a simple notion of completeness for sets of such rules and establish a completeness result. Then we show an equivalence in an appropriate sense between Boolean constraint propagation and unit propagation, a form of resolution for...
cs/0003081
Variable Word Rate N-grams
cs.CL
The rate of occurrence of words is not uniform but varies from document to document. Despite this observation, parameters for conventional n-gram language models are usually derived using the assumption of a constant word rate. In this paper we investigate the use of variable word rate assumption, modelled by a Poiss...
cs/0003082
Representation results for defeasible logic
cs.LO cs.AI
The importance of transformations and normal forms in logic programming, and generally in computer science, is well documented. This paper investigates transformations and normal forms in the context of Defeasible Logic, a simple but efficient formalism for nonmonotonic reasoning based on rules and priorities. The tr...
cs/0003083
Advances in domain independent linear text segmentation
cs.CL
This paper describes a method for linear text segmentation which is twice as accurate and over seven times as fast as the state-of-the-art (Reynar, 1998). Inter-sentence similarity is replaced by rank in the local context. Boundary locations are discovered by divisive clustering.
cs/0003084
Information Extraction from Broadcast News
cs.CL
This paper discusses the development of trainable statistical models for extracting content from television and radio news broadcasts. In particular we concentrate on statistical finite state models for identifying proper names and other named entities in broadcast speech. Two models are presented: the first represen...
cs/0004001
A Theory of Universal Artificial Intelligence based on Algorithmic Complexity
cs.AI cs.IT cs.LG math.IT
Decision theory formally solves the problem of rational agents in uncertain worlds if the true environmental prior probability distribution is known. Solomonoff's theory of universal induction formally solves the problem of sequence prediction for unknown prior distribution. We combine both ideas and get a parameterl...
cs/0004002
Programming in Alma-0, or Imperative and Declarative Programming Reconciled
cs.LO cs.AI cs.PL
In (Apt et al, TOPLAS 1998) we introduced the imperative programming language Alma-0 that supports declarative programming. In this paper we illustrate the hybrid programming style of Alma-0 by means of various examples that complement those presented in (Apt et al, TOPLAS 1998). The presented Alma-0 programs illustr...
cs/0004003
Searching for Spaceships
cs.AI nlin.CG
We describe software that searches for spaceships in Conway's Game of Life and related two-dimensional cellular automata. Our program searches through a state space related to the de Bruijn graph of the automaton, using a method that combines features of breadth first and iterative deepening search, and includes fast...
cs/0004005
Exact Phase Transitions in Random Constraint Satisfaction Problems
cs.AI cs.CC cs.DM
In this paper we propose a new type of random CSP model, called Model RB, which is a revision to the standard Model B. It is proved that phase transitions from a region where almost all problems are satisfiable to a region where almost all problems are unsatisfiable do exist for Model RB as the number of variables ap...
cs/0004007
Deciding first-order properties of locally tree-decomposable structures
cs.DS cs.CC cs.DB
We introduce the concept of a class of graphs, or more generally, relational structures, being locally tree-decomposable. There are numerous examples of locally tree-decomposable classes, among them the class of planar graphs and all classes of bounded valence or of bounded tree-width. We also consider a slightly mor...
cs/0004008
How to Evaluate your Question Answering System Every Day and Still Get Real Work Done
cs.CL cs.IR
In this paper, we report on Qaviar, an experimental automated evaluation system for question answering applications. The goal of our research was to find an automatically calculated measure that correlates well with human judges' assessment of answer correctness in the context of question answering tasks. Qaviar judg...
cs/0004010
Design and Evaluation of Mechanisms for a Multicomputer Object Store
cs.DC cs.DB
Multicomputers have traditionally been viewed as powerful compute engines. It is from this perspective that they have been applied to various problems in order to achieve significant performance gains. There are many applications for which this compute intensive approach is only a partial solution. CAD, virtual reali...
cs/0004012
Assisted Video Sequences Indexing : Motion Analysis Based on Interest Points
cs.CV
This work deals with content-based video indexing. Our viewpoint is semi-automatic analysis of compressed video. We consider the possible applications of motion analysis and moving object detection : assisting moving object indexing, summarising videos, and allowing image and motion queries. We propose an approach ba...
cs/0004016
Looking at discourse in a corpus: The role of lexical cohesion
cs.CL
This paper is aimed at reporting on the development and application of a computer model for discourse analysis through segmentation. Segmentation refers to the principled division of texts into contiguous constituents. Other studies have looked at the application of a number of models to the analysis of discourse by ...
cs/0005001
Robustness of Regional Matching Scheme over Global Matching Scheme
cs.CV
The paper has established and verified the theory prevailing widely among image and pattern recognition specialists that the bottom-up indirect regional matching process is the more stable and the more robust than the global matching process against concentrated types of noise represented by clutter, outlier or occlu...
cs/0005006
A Simple Approach to Building Ensembles of Naive Bayesian Classifiers for Word Sense Disambiguation
cs.CL
This paper presents a corpus-based approach to word sense disambiguation that builds an ensemble of Naive Bayesian classifiers, each of which is based on lexical features that represent co--occurring words in varying sized windows of context. Despite the simplicity of this approach, empirical results disambiguating t...
cs/0005008
A Denotational Semantics for First-Order Logic
cs.PL cs.AI
In Apt and Bezem [AB99] (see cs.LO/9811017) we provided a computational interpretation of first-order formulas over arbitrary interpretations. Here we complement this work by introducing a denotational semantics for first-order logic. Additionally, by allowing an assignment of a non-ground term to a variable we intro...
cs/0005009
PSPACE Reasoning for Graded Modal Logics
cs.LO cs.AI cs.CC cs.DS
We present a PSPACE algorithm that decides satisfiability of the graded modal logic Gr(K_R)---a natural extension of propositional modal logic K_R by counting expressions---which plays an important role in the area of knowledge representation. The algorithm employs a tableaux approach and is the first known algorithm...
cs/0005010
Extending and Implementing the Stable Model Semantics
cs.LO cs.AI
An algorithm for computing the stable model semantics of logic programs is developed. It is shown that one can extend the semantics and the algorithm to handle new and more expressive types of rules. Emphasis is placed on the use of efficient implementation techniques. In particular, an implementation of lookahead th...
cs/0005011
An Average Analysis of Backtracking on Random Constraint Satisfaction Problems
cs.CC cs.AI
In this paper we propose a random CSP model, called Model GB, which is a natural generalization of standard Model B. It is proved that Model GB in which each constraint is easy to satisfy exhibits non-trivial behaviour (not trivially satisfiable or unsatisfiable) as the number of variables approaches infinity. A deta...
cs/0005012
Reasoning with Axioms: Theory and Pratice
cs.LO cs.AI
When reasoning in description, modal or temporal logics it is often useful to consider axioms representing universal truths in the domain of discourse. Reasoning with respect to an arbitrary set of axioms is hard, even for relatively inexpressive logics, and it is essential to deal with such axioms in an efficient ma...