Generic programming is accepted by the functionalprogramming community as a valuable tool for program development. Several functional languages have adopted the generic scheme of type-indexed values. this scheme work...
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ISBN:
(纸本)3540243623
Generic programming is accepted by the functionalprogramming community as a valuable tool for program development. Several functional languages have adopted the generic scheme of type-indexed values. this scheme works by specialization of a generic function to a concrete type. However, the generated code is extremely inefficient compared to its hand-written counterpart. the performance penalty is so big that the practical usefulness of generic programming is compromised. In this paper we present an optimization algorithm that is able to completely eliminate the overhead introduced by the specialization scheme for a large class of generic functions. the presented technique is based on consumer-producer elimination as exploited by fusion, a standard general purpose optimization method. We show that our algorithm is able to optimize many practical examples of generic functions.
Program inversion is a fundamental concept in program transformation. We describe the principles behind an automatic program inverter, which we developed for a first-order functional language, and show several inverse...
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ISBN:
(纸本)3540243623
Program inversion is a fundamental concept in program transformation. We describe the principles behind an automatic program inverter, which we developed for a first-order functional language, and show several inverse programs automatically produced by our system. the examples belong to different application areas, including encoding and decoding, printing and parsing, and bidirectional data conversion. the core of the system uses a stack-based language, local inversion, and eliminates nondeterminism by applying methods from parsing theory.
Defeasible reasoning is a rule-based approach for efficient reasoning with incomplete and inconsistent information. Such reasoning is, among others, useful for ontology integration, where conflicting information arise...
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Defeasible reasoning is a rule-based approach for efficient reasoning with incomplete and inconsistent information. Such reasoning is, among others, useful for ontology integration, where conflicting information arises naturally;and for the modeling of business rules and policies, where rules with exceptions are often used. this paper describes these scenarios in more detail, and reports on the implementation of a system for defeasible reasoning on the Web. the system (a) is syntactically compatible with RuleML;(b) features strict and defeasible rules, priorities and two kinds of negation;(c) is based on a translation to logicprogramming with declarative semantics;(d) is flexible and adaptable to different intuitions within defeasible reasoning;and (e) can reason with rules, RDF, RDF Schema and (parts of) OWL ontologies.
the hybrid probabilistic programs framework [1] allows the user to explicitly encode bothlogical and statistical knowledge available about the dependency among the events in the program. In this paper, we extend the ...
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ISBN:
(纸本)3540243623
the hybrid probabilistic programs framework [1] allows the user to explicitly encode bothlogical and statistical knowledge available about the dependency among the events in the program. In this paper, we extend the language of hybrid probabilistic programs by allowing disjunctive composition functions to be associated with heads of clauses, and we modify its semantics to make it more suitable to encode real-world applications. the new semantics is a natural extension of standard logicprogramming semantics. the new semantics of hybrid probabilistic programs also subsumes the implication-based probabilistic approach proposed by Lakshmanan and Sadri [12]. We provide also a sound and complete algorithm to compute the least fixpoint of hybrid probabilistic programs with annotated atomic formulas as rule heads.
In this paper we apply integer programming (IP) based techniques to the problem of delay balancing in wave-pipelined circuits. the proposed approach considers delays, as well as fan-in and fan-out associated with ever...
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ISBN:
(纸本)0769524532
In this paper we apply integer programming (IP) based techniques to the problem of delay balancing in wave-pipelined circuits. the proposed approach considers delays, as well as fan-in and fan-out associated with every node in the circuit. After a weighted graph representation of the circuit is formed a node collapsing procedure is used to preprocess (reduce the size of) the system and to obtain the final formulation of the IP problem, which is solved by using a branch and bound heuristic to acquire a minimum delay in the circuit. We also compare the proposed technique with application - to the same problem - of a linear programming solver.
We describe the design of the OLPS system, an implementation of the preferred answer set semantics for ordered logic programs. the basic algorithm we propose computes the extended answer sets of a simple program using...
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ISBN:
(纸本)3540243623
We describe the design of the OLPS system, an implementation of the preferred answer set semantics for ordered logic programs. the basic algorithm we propose computes the extended answer sets of a simple program using an intuitive 9-valued lattice, called T-9. During the computation, this lattice is employed to keep track of the status of the literals and the rules while evolving to a solution. It turns out that the basic algorithm needs little modification in order to be able to compute the preferred answer sets of an ordered logic program. We illustrate the system using an example from diagnostic reasoning and we present some preliminary benchmark results comparing OLPS with existing answer set solvers such as SMODELS and DLV.
Revising and updating knowledge bases is an important issue in knowledge representation and reasoning. Various proposals have been made recently for updating logic programs, in particular with respect to answer set pr...
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Revising and updating knowledge bases is an important issue in knowledge representation and reasoning. Various proposals have been made recently for updating logic programs, in particular with respect to answer set programming. So far, most of these approaches are based on the causal rejection principle but most of them are showing an unintuitive behaviour. Our update semantics (based on minimal generalised answer sets) satisfies several structural properties and avoids problems of the other proposals. In additionwe introduce some new properties that we consider an updating/dynamic semantics should fulfill too: Weak Irrelevance of Syntax and Strong Consistency. We compare our approach withthe well-known upd operator due to Eiter et al. and show that it satisfies the new properties.
the need for direct memory manipulation through pointers is essential in many applications. However, it is also commonly understood that the use (or probably misuse) of pointers is often a rich source of program error...
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ISBN:
(纸本)3540243623
the need for direct memory manipulation through pointers is essential in many applications. However, it is also commonly understood that the use (or probably misuse) of pointers is often a rich source of program errors. therefore, approaches that can effectively enforce safe use of pointers in programming are highly sought after. ATS is a programming language with a type system rooted in a recently developed framework Applied Type System, and a novel and desirable feature in ATS lies in its support for safe programming with pointers through a novel notion of stateful views. In particular, even pointer arithmetic is allowed in ATS and guaranteed to be safe by the type system of ATS. In this paper, we give an overview of this feature in ATS, presenting some interesting examples based on a prototype implementation of ATS to demonstrate the practicality of safe programming with pointer through stateful views.
We describe the current capabilities of a system for rule-based programming which is being developed by us. the system is called ρLog and consists of a pattern matching system and a strategic programming system embed...
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the goal of this paper is to improve the type error messages in the presence of Haskell 98 type classes, in particular for the nonexpert user. As a language feature, type classes are very pervasive, and strongly influ...
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ISBN:
(纸本)3540243623
the goal of this paper is to improve the type error messages in the presence of Haskell 98 type classes, in particular for the nonexpert user. As a language feature, type classes are very pervasive, and strongly influence what is reported and when, even in relatively simple programs. We propose four type class directives, and specialized type rules, to lend high-level support to compilers to improve the type error messages. Both have been implemented, and can be used to easily modify the behavior of the type inference process.
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