OpenRaiser/Intern-Atlas huggingface dataset:
Minimal-Change Integrity Maintenance Using Tuple Deletions
Venue: arXiv cs.DB 2002
Year: 2002

We address the problem of minimal-change integrity maintenance in the context of integrity constraints in relational databases. We assume that integrity-restoration actions are limited to tuple deletions. We identify two basic computational issues: repair checking (is a database instance a repair of a given database?) and consistent query answers (is a tuple an answer to a given query in every repair of a given database?). We study the computational complexity of both problems, delineating the boundary between the tractable and the intractable. We consider denial constraints, general functional and inclusion dependencies, as well as key and foreign key constraints. Our results shed light on the computational feasibility of minimal-change integrity maintenance. The tractable cases should lead to practical implementations. The intractability results highlight the inherent limitations of any integrity enforcement mechanism, e.g., triggers or referential constraint actions, as a way of performing minimal-change integrity maintenance.
Answering Subcognitive Turing Test Questions: A Reply to French
Venue: arXiv cs.CL 2002
Year: 2002

Robert French has argued that a disembodied computer is incapable of passing a Turing Test that includes subcognitive questions. Subcognitive questions are designed to probe the network of cultural and perceptual associations that humans naturally develop as we live, embodied and embedded in the world. In this paper, I show how it is possible for a disembodied computer to answer subcognitive questions appropriately, contrary to French's claim. My approach to answering subcognitive questions is to use statistical information extracted from a very large collection of text. In particular, I show how it is possible to answer a sample of subcognitive questions taken from French, by issuing queries to a search engine that indexes about 350 million Web pages. This simple algorithm may shed light on the nature of human (sub-) cognition, but the scope of this paper is limited to demonstrating that French is mistaken: a disembodied computer can answer subcognitive questions.
Learning Algorithms for Keyphrase Extraction
Venue: arXiv cs.LG 2002
Year: 2002

Many academic journals ask their authors to provide a list of about five to fifteen keywords, to appear on the first page of each article. Since these key words are often phrases of two or more words, we prefer to call them keyphrases. There is a wide variety of tasks for which keyphrases are useful, as we discuss in this paper. We approach the problem of automatically extracting keyphrases from text as a supervised learning task. We treat a document as a set of phrases, which the learning algorithm must learn to classify as positive or negative examples of keyphrases. Our first set of experiments applies the C4.5 decision tree induction algorithm to this learning task. We evaluate the performance of nine different configurations of C4.5. The second set of experiments applies the GenEx algorithm to the task. We developed the GenEx algorithm specifically for automatically extracting keyphrases from text. The experimental results support the claim that a custom-designed algorithm (GenEx), incorporating specialized procedural domain knowledge, can generate better keyphrases than a generalpurpose algorithm (C4.5). Subjective human evaluation of the keyphrases generated by Extractor suggests that about 80% of the keyphrases are acceptable to human readers. This level of performance should be satisfactory for a wide variety of applications.
Unsupervised Language Acquisition: Theory and Practice
Venue: arXiv cs.CL 2002
Year: 2002

In this thesis I present various algorithms for the unsupervised machine learning of aspects of natural languages using a variety of statistical models. The scientific object of the work is to examine the validity of the so-called Argument from the Poverty of the Stimulus advanced in favour of the proposition that humans have language-specific innate knowledge. I start by examining an a priori argument based on Gold's theorem, that purports to prove that natural languages cannot be learned, and some formal issues related to the choice of statistical grammars rather than symbolic grammars. I present three novel algorithms for learning various parts of natural languages: first, an algorithm for the induction of syntactic categories from unlabelled text using distributional information, that can deal with ambiguous and rare words; secondly, a set of algorithms for learning morphological processes in a variety of languages, including languages such as Arabic with non-concatenative morphology; thirdly an algorithm for the unsupervised induction of a context-free grammar from tagged text. I carefully examine the interaction between the various components, and show how these algorithms can form the basis for a empiricist model of language acquisition. I therefore conclude that the Argument from the Poverty of the Stimulus is unsupported by the evidence.
Myths and Legends of the Baldwin Effect
Venue: arXiv cs.LG 2002
Year: 2002

This position paper argues that the Baldwin effect is widely misunderstood by the evolutionary computation community. The misunderstandings appear to fall into two general categories. Firstly, it is commonly believed that the Baldwin effect is concerned with the synergy that results when there is an evolving population of learning individuals. This is only half of the story. The full story is more complicated and more interesting. The Baldwin effect is concerned with the costs and benefits of lifetime learning by individuals in an evolving population. Several researchers have focussed exclusively on the benefits, but there is much to be gained from attention to the costs. This paper explains the two sides of the story and enumerates ten of the costs and benefits of lifetime learning by individuals in an evolving population. Secondly, there is a cluster of misunderstandings about the relationship between the Baldwin effect and Lamarckian inheritance of acquired characteristics. The Baldwin effect is not Lamarckian. A Lamarckian algorithm is not better for most evolutionary computing problems than a Baldwinian algorithm. Finally, Lamarckian inheritance is not a better model of memetic (cultural) evolution than the Baldwin effect.
Interval Constraint Solving for Camera Control and Motion Planning
Venue: arXiv cs.AI 2003
Year: 2003

Many problems in robust control and motion planning can be reduced to either find a sound approximation of the solution space determined by a set of nonlinear inequalities, or to the ``guaranteed tuning problem'' as defined by Jaulin and Walter, which amounts to finding a value for some tuning parameter such that a set of inequalities be verified for all the possible values of some perturbation vector. A classical approach to solve these problems, which satisfies the strong soundness requirement, involves some quantifier elimination procedure such as Collins' Cylindrical Algebraic Decomposition symbolic method. Sound numerical methods using interval arithmetic and local consistency enforcement to prune the search space are presented in this paper as much faster alternatives for both soundly solving systems of nonlinear inequalities, and addressing the guaranteed tuning problem whenever the perturbation vector has dimension one. The use of these methods in camera control is investigated, and experiments with the prototype of a declarative modeller to express camera motion using a cinematic language are reported and commented.
Inference of termination conditions for numerical loops in Prolog
Venue: arXiv cs.PL 2003
Year: 2003

We present a new approach to termination analysis of numerical computations in logic programs. Traditional approaches fail to analyse them due to non well-foundedness of the integers. We present a technique that allows overcoming these difficulties. Our approach is based on transforming a program in a way that allows integrating and extending techniques originally developed for analysis of numerical computations in the framework of query-mapping pairs with the well-known framework of acceptability. Such an integration not only contributes to the understanding of termination behaviour of numerical computations, but also allows us to perform a correct analysis of such computations automatically, by extending previous work on a constraint-based approach to termination. Finally, we discuss possible extensions of the technique, including incorporating general term orderings.
Anticipatory Guidance of Plot
Venue: arXiv cs.AI 2003
Year: 2003

An anticipatory system for guiding plot development in interactive narratives is described. The executable model is a finite automaton that provides the implemented system with a look-ahead. The identification of undesirable future states in the model is used to guide the player, in a transparent manner. In this way, too radical twists of the plot can be avoided. Since the player participates in the development of the plot, such guidance can have many forms, depending on the environment of the player, on the behavior of the other players, and on the means of player interaction. We present a design method for interactive narratives which produces designs suitable for the implementation of anticipatory mechanisms. Use of the method is illustrated by application to our interactive computer game Kaktus.
A Paraconsistent Higher Order Logic
Venue: arXiv cs.LO 2003
Year: 2003

Classical logic predicts that everything (thus nothing useful at all) follows from inconsistency. A paraconsistent logic is a logic where an inconsistency does not lead to such an explosion, and since in practice consistency is difficult to achieve there are many potential applications of paraconsistent logics in knowledge-based systems, logical semantics of natural language, etc. Higher order logics have the advantages of being expressive and with several automated theorem provers available. Also the type system can be helpful. We present a concise description of a paraconsistent higher order logic with countable infinite indeterminacy, where each basic formula can get its own indeterminate truth value (or as we prefer: truth code). The meaning of the logical operators is new and rather different from traditional many-valued logics as well as from logics based on bilattices. The adequacy of the logic is examined by a case study in the domain of medicine. Thus we try to build a bridge between the HOL and MVL communities. A sequent calculus is proposed based on recent work by Muskens.
Preemptive Scheduling of Equal-Length Jobs to Maximize Weighted Throughput
Venue: arXiv cs.DS 2003
Year: 2003

We study the problem of computing a preemptive schedule of equal-length jobs with given release times, deadlines and weights. Our goal is to maximize the weighted throughput, which is the total weight of completed jobs. In Graham's notation this problem is described as (1 | r_j;p_j=p;pmtn | sum w_j U_j). We provide an O(n^4)-time algorithm for this problem, improving the previous bound of O(n^{10}) by Baptiste.
A uniform approach to logic programming semantics
Venue: arXiv cs.AI 2003
Year: 2003

Part of the theory of logic programming and nonmonotonic reasoning concerns the study of fixed-point semantics for these paradigms. Several different semantics have been proposed during the last two decades, and some have been more successful and acknowledged than others. The rationales behind those various semantics have been manifold, depending on one's point of view, which may be that of a programmer or inspired by commonsense reasoning, and consequently the constructions which lead to these semantics are technically very diverse, and the exact relationships between them have not yet been fully understood. In this paper, we present a conceptually new method, based on level mappings, which allows to provide uniform characterizations of different semantics for logic programs. We will display our approach by giving new and uniform characterizations of some of the major semantics, more particular of the least model semantics for definite programs, of the Fitting semantics, and of the well-founded semantics. A novel characterization of the weakly perfect model semantics will also be provided.
PHORMA: Perfectly Hashed Order Restricted Multidimensional Array
Venue: arXiv cs.DM 2003
Year: 2003

In this paper we propose a simple and efficient strategy to obtain a data structure generator to accomplish a perfect hash of quite general order restricted multidimensional arrays named {\em phormas}. The constructor of such objects gets two parameters as input: an n-vector a of non negative integers and a boolean function B on the types of order restrictions on the coordinates of the valid n-vectors bounded by a. At compiler time, the phorma constructor builds, from the pair a,B, a digraph G(a,B) with a single source s and a single sink t such that the st-paths are in 1-1 correspondence with the members of the B-restricted a-bounded array A(a,B). Besides perfectly hashing A(a,B), G(a,B) is an instance of an NW-family. This permits other useful computational tasks on it.
A comparison of four approaches to the calculation of conservation laws
Venue: arXiv cs.SC 2003
Year: 2003

The paper compares computational aspects of four approaches to compute conservation laws of single differential equations (DEs) or systems of them, ODEs and PDEs. The only restriction, required by two of the four corresponding computer algebra programs, is that each DE has to be solvable for a leading derivative. Extra constraints for the conservation laws can be specified. Examples include new conservation laws that are non-polynomial in the functions, that have an explicit variable dependence and families of conservation laws involving arbitrary functions. The following equations are investigated in examples: Ito, Liouville, Burgers, Kadomtsev-Petviashvili, Karney-Sen-Chu-Verheest, Boussinesq, Tzetzeica, Benney.
Algorithms using Java for Spreadsheet Dependent Cell Recomputation
Venue: arXiv cs.DS 2003
Year: 2003

Java implementations of algorithms used by spreadsheets to automatically recompute the set of cells dependent on a changed cell are described using a mathematical model for spreadsheets based on graph theory. These solutions comprise part of a Java API that allows a client application to read, modify, and maintain spreadsheet data without using the spreadsheet application program that produced it. Features of the Java language that successfully improve the running time performance of the algorithms are also described.
Barnacle: An Assembly Algorithm for Clone-based Sequences of Whole Genomes
Venue: arXiv cs.DS 2003
Year: 2003

We propose an assembly algorithm {\sc Barnacle} for sequences generated by the clone-based approach. We illustrate our approach by assembling the human genome. Our novel method abandons the original physical-mapping-first framework. As we show, {\sc Barnacle} more effectively resolves conflicts due to repeated sequences. The latter is the main difficulty of the sequence assembly problem. Inaddition, we are able to detect inconsistencies in the underlying data. We present and compare our results on the December 2001 freeze of the public working draft of the human genome with NCBI's assembly (Build 28). The assembly of December 2001 freeze of the public working draft generated by {\sc Barnacle} and the source code of {\sc Barnacle} are available at (http://www.cs.rutgers.edu/~vchoi).
G-Monitor: Gridbus web portal for monitoring and steering application execution on global grids
Venue: arXiv cs.DC 2003
Year: 2003

Grids are experiencing a rapid growth in their application and along with this there is a requirement for a portal which is easy to use and scalable. We have responded to this requirement by developing an easy to use, scalable, web-based portal called G-Monitor. This paper proposes a generic architecture for a web portal into a grid environment and discusses our implementation and its application.
Visual Environment for Rapid Composition of Parameter-Sweep Applications for Distributed Processing on Global Grids
Venue: arXiv cs.DC 2003
Year: 2003

Computational Grids are emerging as a platform for next-generation parallel and distributed computing. Large-scale parametric studies and parameter sweep applications find a natural place in the Grid?s distribution model. There is little or no communication between jobs. The task of parallelizing and distributing existing applications is conceptually trivial. These properties of parametric studies make it an ideal place to start developing integrated development environments (IDEs) for rapidly Grid-enabling applications. However, the availability of IDEs for scientists to Grid-enable their applications, without the need of developing them as parallel applications explicitly, is still lacking. This paper presents a Java based IDE called Visual Parametric Tool (VPT), developed as part of the Gridbus project, for rapid creation of parameter sweep (data parallel/SPMD) applications. It supports automatic creation of parameter script and parameterisation of the input data files, which is compatible with the Nimrod-G parameter specification language. The usefulness of VPT is demonstrated by a case study on composition of molecular docking application as a parameter sweep application. Such applications can be deployed on clusters using the Nimrod/enFuzion system and on global Grids using the Nimrod-G grid resource broker.
Authenticated Append-only Skip Lists
Venue: arXiv cs.CR 2003
Year: 2003

In this work we describe, design and analyze the security of a tamper-evident, append-only data structure for maintaining secure data sequences in a loosely coupled distributed system where individual system components may be mutually distrustful. The resulting data structure, called an Authenticated Append-Only Skip List (AASL), allows its maintainers to produce one-way digests of the entire data sequence, which they can publish to others as a commitment on the contents and order of the sequence. The maintainer can produce efficiently succinct proofs that authenticate a particular datum in a particular position of the data sequence against a published digest. AASLs are secure against tampering even by malicious data structure maintainers. First, we show that a maintainer cannot ``invent'' and authenticate data elements for the AASL after he has committed to the structure. Second, he cannot equivocate by being able to prove conflicting facts about a particular position of the data sequence. This is the case even when the data sequence grows with time and its maintainer publishes successive commitments at times of his own choosing. AASLs can be invaluable in reasoning about the integrity of system logs maintained by untrusted components of a loosely-coupled distributed system.
An Algorithm for Aligning Sentences in Bilingual Corpora Using Lexical Information
Venue: arXiv cs.CL 2003
Year: 2003

In this paper we describe an algorithm for aligning sentences with their translations in a bilingual corpus using lexical information of the languages. Existing efficient algorithms ignore word identities and consider only the sentence lengths (Brown, 1991; Gale and Church, 1993). For a sentence in the source language text, the proposed algorithm picks the most likely translation from the target language text using lexical information and certain heuristics. It does not do statistical analysis using sentence lengths. The algorithm is language independent. It also aids in detecting addition and deletion of text in translations. The algorithm gives comparable results with the existing algorithms in most of the cases while it does better in cases where statistical algorithms do not give good results.
Analytical formulations of Peer-to-Peer Connection Efficiency
Venue: arXiv cs.DC 2003
Year: 2003

Use of Peer-to-Peer (P2P) service networks introduces a new communication paradigm because peers are both clients and servers and so each peer may provide/request services to/from other peers. Empirical studies of P2P networks have been undertaken and reveal useful characteristics. However there is to date little analytical work to describe P2P networks with respect to their communication paradigm and their interconnections. This paper provides an analytical formulation and optimisation of peer connection efficiency, in terms of minimising the fraction of wasted connection time. Peer connection efficiency is analysed for both a uni- and multi-connected peer. Given this fundamental optimisation, the paper optimises the number of connections that peers should make use of as a function of network load, in terms of minimising the total queue size that requests in the P2P network experience. The results of this paper provide a basis for engineering high performance P2P interconnection networks. The optimisations are useful for reducing bandwidth and power consumption, e.g. in the case of peers being mobile devices with a limited power supply. Also these results could be used to determine when a (virtual) circuit should be switched to support a connection.
The Boolean Functions Computed by Random Boolean Formulas OR How to Grow the Right Function
Venue: arXiv cs.DM 2003
Year: 2003

Among their many uses, growth processes (probabilistic amplification), were used for constructing reliable networks from unreliable components, and deriving complexity bounds of various classes of functions. Hence, determining the initial conditions for such processes is an important and challenging problem. In this paper we characterize growth processes by their initial conditions and derive conditions under which results such as Valiant's (1984) hold. First, we completely characterize growth processes that use linear connectives. Second, by extending Savický's (1990) analysis, via ``Restriction Lemmas'', we characterize growth processes that use monotone connectives, and show that our technique is applicable to growth processes that use other connectives as well. Additionally, we obtain explicit bounds on the convergence rates of several growth processes, including the growth process studied by Savický (1990).
Defeasible Logic Programming: An Argumentative Approach
Venue: arXiv cs.AI 2003
Year: 2003

The work reported here introduces Defeasible Logic Programming (DeLP), a formalism that combines results of Logic Programming and Defeasible Argumentation. DeLP provides the possibility of representing information in the form of weak rules in a declarative manner, and a defeasible argumentation inference mechanism for warranting the entailed conclusions. In DeLP an argumentation formalism will be used for deciding between contradictory goals. Queries will be supported by arguments that could be defeated by other arguments. A query q will succeed when there is an argument A for q that is warranted, ie, the argument A that supports q is found undefeated by a warrant procedure that implements a dialectical analysis. The defeasible argumentation basis of DeLP allows to build applications that deal with incomplete and contradictory information in dynamic domains. Thus, the resulting approach is suitable for representing agent's knowledge and for providing an argumentation based reasoning mechanism to agents.
Constraint-based analysis of composite solvers
Venue: arXiv cs.AI 2003
Year: 2003

Cooperative constraint solving is an area of constraint programming that studies the interaction between constraint solvers with the aim of discovering the interaction patterns that amplify the positive qualities of individual solvers. Automatisation and formalisation of such studies is an important issue of cooperative constraint solving. In this paper we present a constraint-based analysis of composite solvers that integrates reasoning about the individual solvers and the processed data. The idea is to approximate this reasoning by resolution of set constraints on the finite sets representing the predicates that express all the necessary properties. We illustrate application of our analysis to two important cooperation patterns: deterministic choice and loop.