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Diagnostic Agents for Distributed Systems
, 1997
"... In this paper we introduce an agentbased framework for the diagnosis of spatially distributed technical systems, based on a suitable distributed diagnosis architecture. We implement the framework using the concepts of vivid agents and extended logic programming. To demonstrate the power of our appr ..."
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In this paper we introduce an agentbased framework for the diagnosis of spatially distributed technical systems, based on a suitable distributed diagnosis architecture. We implement the framework using the concepts of vivid agents and extended logic programming. To demonstrate the power of our approach, we solve a diagnosis example from the domain of unreliable datagram protocols.
REVISE: Logic Programming and Diagnosis
, 1997
"... In this article we describe the nonmonotonic reasoning system REVISE that revises contradictory extended logic programs. We sketch the REVISE algorithm and evaluate it in the domain of digital circuits. ..."
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Cited by 26 (19 self)
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In this article we describe the nonmonotonic reasoning system REVISE that revises contradictory extended logic programs. We sketch the REVISE algorithm and evaluate it in the domain of digital circuits.
ModelBased Analogue Circuit Diagnosis with CLP(R)
"... Modelbased diagnosis is the activity of locating malfunctioning components of a system solely on the basis of its structure and behavior. Diagnostic systems usually rely on qualitative models and reason by local constraint propagation methods. However, there is a large class of applications where A ..."
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Cited by 5 (5 self)
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Modelbased diagnosis is the activity of locating malfunctioning components of a system solely on the basis of its structure and behavior. Diagnostic systems usually rely on qualitative models and reason by local constraint propagation methods. However, there is a large class of applications where ATMSlike systems or pure logic programs are unpractical since they are unable to solve simultaneous equations. In particular, modeling realvalued system parameters with tolerances requires some degree of numerical processing, and feedback loops in general cannot be resolved by Appears in Proc. 4th Intl. GI Congress (W. Brauer, D. Hernandez, Eds.), pp. 343353, Munchen, October 2324, 1991, SpringerVerlag (IFB 291). local constraint propagation methods. Examples of such systems are analogue circuits, e.g., amplifiers or filters. In the paper we describe the role of Constraint Logic Programs over the domain of reals (CLP(!)) in representing both, qualitative and numerical models. CLP(!)...
Using Extended Logic Programming for AlarmCorrelation in Cellular Phone Networks
"... . Alarm correlation is a necessity in large mobile phone networks, where the alarm bursts resulting from severe failures would otherwise overload the network operators. In this paper, we describe how to realize alarmcorrelation in cellular phone networks using extended logic programming which pr ..."
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. Alarm correlation is a necessity in large mobile phone networks, where the alarm bursts resulting from severe failures would otherwise overload the network operators. In this paper, we describe how to realize alarmcorrelation in cellular phone networks using extended logic programming which provides integrity constraints, implicit, and explicit negation. We solve different scenarios for a GSM network application using the extended logic programming system Revise. 1 Introduction Mobile networks, like the panEuropean GSM networks, are growing rapidly. Alarm handling systems enable the operators to run such networks with minimal operation costs. The goal is to collect and interpret alarm messages and failure indications from the network elements without human intervention. In large networks, like the current GSM networks, the alarm vectors supplied by the network elements tend to flood the workstations of the operators especially in critical situations like the passage of a t...
PolynomialTime ModelBased Diagnosis with the Critical Set Algorithm
 University of Wales, Aberystwith
, 1993
"... Mozetic has recently given an algorithm (called IDA) for polynomialtime diagnosis of systems described using models written in Prolog, under some conditions of which the most important is ignorance of abnormal behavior. Mozetic's algorithm uses models of the system to be written in such a way ..."
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Mozetic has recently given an algorithm (called IDA) for polynomialtime diagnosis of systems described using models written in Prolog, under some conditions of which the most important is ignorance of abnormal behavior. Mozetic's algorithm uses models of the system to be written in such a way that they can be called with a partial instantiation of their parameters and return a full instantiation, a byproduct of the use of Prolog to write the models. We show that the requirement is not necessary to insure polynomialtime diagnosis. We also show that, by exploiting Loveland's critical set algorithms, we can obtain performance comparable to IDA without requiring IDAstyle models. 1
Integrating Numerical and Qualitative Models within Constraint Logic Programming
 IN LOGIC PROGRAMMING: PROCEEDINGS OF THE 1991 INTERNATIONAL SYMPOSIUM
, 1991
"... The paper describes an interplay between numerical and qualitative models represented in a uniform Constraint Logic Programming framework. In the context of modelbased diagnosis a detailed, numerical model is used to discriminate between competing diagnoses at the abstract, qualitative level. A dis ..."
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Cited by 3 (1 self)
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The paper describes an interplay between numerical and qualitative models represented in a uniform Constraint Logic Programming framework. In the context of modelbased diagnosis a detailed, numerical model is used to discriminate between competing diagnoses at the abstract, qualitative level. A distinguishing feature of our approach is that the abstract proof is used to guide the verification at the detailed level, and to refute impossible refinements as soon as possible by introducing additional constraints on the variables. An implemented instance of this framework, CLP(R), which is used in the paper, comprises a solver for systems of linear equations and inequalities over realvalued variables.
ModelBased Diagnosis with Constraint Logic Programs
 Proc. 7th Austrian Conf. on Artificial Intelligence, OGAI91
, 1991
"... Modelbased diagnosis is the activity of locating malfunctioning components of a system solely on the basis of its structure and behavior. In the paper we describe the role of Constraint Logic Programming (CLP) in representing models and the search space of minimal diagnoses. In particular, we conce ..."
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Modelbased diagnosis is the activity of locating malfunctioning components of a system solely on the basis of its structure and behavior. In the paper we describe the role of Constraint Logic Programming (CLP) in representing models and the search space of minimal diagnoses. In particular, we concentrate on two instances of the CLP scheme: CLP(B) and CLP(!). CLP(B) extends the standard computational domain of logic programs by boolean expressions, while CLP(!) comprises a solver for systems of linear equations and inequalities over realvalued variables. 1 Introduction There are two fundamentaly different approaches to diagnostic reasoning. In the first, heuristic approach, one encodes diagnostic rules of thumb and experience of human experts in a given domain. In the second, modelbased approach, one starts with a model of a realworld system which explicitly represents the structure and components of the system (e.g., Genesereth 1984, Davis 1984, de Kleer & Williams 1987, Reiter 198...
Propositional Non Clausal Deduction and Diagnosis
"... form (CNF) or some form which is close to CNF. Therefore, any formula not in CNF must be converted to CNF before applying the diagnosis system. Relying on CNF or any other clause form may cause an exponential blowup even before the diagnosis algorithms can be applied. Efficient clause form transla ..."
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form (CNF) or some form which is close to CNF. Therefore, any formula not in CNF must be converted to CNF before applying the diagnosis system. Relying on CNF or any other clause form may cause an exponential blowup even before the diagnosis algorithms can be applied. Efficient clause form translations [8] commonly used in theorem provers cannot be used here because they do not preserve equivalence during transformation. The diagnosis systems of Reiter [11], de Kleer [2], and of Mozetic and Holzbaur [6] also require the generation of minimal conflicts. Generating minimal conflicts causes an additional blow up. In [10] we describe a new technique for computing minimal diagnoses of a system based on Reiter's theory; also, modifications are introduced so that only single fault diagnoses are generated. This approach does not rely on a clause form representation (although it is applicable to systems represented in clause form), nor does it require generating
Some Applications Of Non Clausal Deduction
, 1995
"... In this thesis it is shown that by using negation normal form for representing propositional formulas, rather than clause forms such as conjunctive and disjunctive normal forms, reasoning systems that are more efficent for many classes of formulas can be built. This is due the fact that the process ..."
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In this thesis it is shown that by using negation normal form for representing propositional formulas, rather than clause forms such as conjunctive and disjunctive normal forms, reasoning systems that are more efficent for many classes of formulas can be built. This is due the fact that the process of converting arbitrary propositional formulas into clause forms is an expensive computational task. Algorithms for two related problems in artificial intelligence, namely computing prime implicates and implicants, and computing minimal diagnoses are developed and implemented. These algorithms use negation normal form for representing proportional formulas. These algorithms are based on dissolution, an inference rule for negation normal form. Through theoretical and experimental analysis it is shown that these algorithms are superior to many clausebased algorithms. Antilinks are defined and certain operations based on them are introduced. By performing these operations, many nonprime implicants/implicates and many nonminimal diagnoses can be eliminated without doing expensive subsumption checks. Experimental results showing significant improvements obtained by using these operations are also given. An algorithm for computing prime implicants and implicates of multiplevalued logics is also developed. This algorithm is based on signed dissolution, an inference rule for multiplevalued logics. Acknowledgments I am deeply indebted to my thesis advisor Professor Neil V. Murray, for suggesting the topic to me, and for providing suggestions and comments which were crucial in the development of this thesis. He also introduced me to the exciting topic of automated reasoning. His constructive criticism helped in improving my writing and presentation skills. I would also like ...