This article examines the methods how to avoid an overfitting-effect within GeLog-systems. This effect can be observed in nearly all systems of inductive concept learning, if due to false classification of examples fa...
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ISBN:
(纸本)3540408045
This article examines the methods how to avoid an overfitting-effect within GeLog-systems. This effect can be observed in nearly all systems of inductive concept learning, if due to false classification of examples false, especially too specific theories, axe learned. There are a number or procedures, how to counter the effects of the overfitting-effect or to avoid it. This article develops criteria for the selection of those procedures. In this context, the integrability into the GeLog-system, a system of genetic inductive logic programming, is of great importance. Finally, a filter procedure, based on the correlation heuristic, which is also used for top-down-pruning, is selected, as it promised the possible application. to. a, relatively huge amount of problems. After that, the efficiency of the methods will be proven with the help of systematic experiments.
it is generally thought that reasoning about programs in memory safe, garbage collected languages is much easier than in languages where the programmer has more explicit control over memory. Paradoxically, existing pr...
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it is generally thought that reasoning about programs in memory safe, garbage collected languages is much easier than in languages where the programmer has more explicit control over memory. Paradoxically, existing program logics are based on a low-level view of storage that is sensitive to the presence or absence of unreachable cells, and Reynolds has pointed out that the Hoare triples derivable in these logics are even incompatible with garbage collection. We present a study of a small language whose operational semantics includes a rule for reclaiming garbage. Our main results include an analysis of propositions that are garbage insensitive, and full abstraction results connecting partial and total correctness to two natural notions of observational equivalence between programs. (C) 2002 Elsevier Science B.V. All rights reserved.
Visualization has played a significant role in understanding the behavior of distributed programs. We propose a visualization that shows message exchanges in distributed logic programs using the Program Structure View...
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ISBN:
(纸本)1892512459
Visualization has played a significant role in understanding the behavior of distributed programs. We propose a visualization that shows message exchanges in distributed logic programs using the Program Structure View in NaraView. The behavior of distributed logic programs is easily visualized using the Program Structure View since the messages have three parametric factors: time, derivation, and hierarchical level.
Tabling has emerged as an important evaluation technique in logic programming. Currently, changes to a program (due to addition/deletion of rules/facts) after query evaluation compromise the completeness and soundness...
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ISBN:
(纸本)3540206426
Tabling has emerged as an important evaluation technique in logic programming. Currently, changes to a program (due to addition/deletion of rules/facts) after query evaluation compromise the completeness and soundness of the answers in the tables. This paper presents incremental algorithms for maintaining the freshness of tables upon addition or deletion of facts. Our algorithms improve on existing materialized view maintenance algorithms and can be easily extended to handle changes to rules as well. We describe an implementation of our algorithms in the XSB tabled logic programming system. Preliminary experimental results indicate that our incremental algorithms are efficient. Our implementation represents a first step towards building a practical system for incremental evaluation of tabled logic programs.
Clones of logic functions form an algebraic lattice, which in the case of Boolean functions was completely described by *** in 1941. This lattice, often referred to as the Post Lattice, has been well studied from vari...
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ISBN:
(纸本)0769519180
Clones of logic functions form an algebraic lattice, which in the case of Boolean functions was completely described by *** in 1941. This lattice, often referred to as the Post Lattice, has been well studied from various angles, particularly, the generation of the Post Lattice by its subsets. This paper discusses the results about clones that are irreducible by means of meet- and/or join-operations of the lattice. We show that the join-irreducible clones generate the Post Lattice, and dually, the meet-irreducible clones generate the Post Lattice. We present a complete description of such generation in both cases. We observe that any clone can be presented as a join or meet of at most two irreducible clones. In the former case each clone is the join of at most four join-irreducible clones and in the latter case each clone is the meet of at most three meet- irreducible ones.
This paper presents a logic based approach to hardware abstraction and composition based on the logic programming language Prolog. This is an attempt to satisfy the dual requirement of abstract hardware design and har...
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ISBN:
(纸本)0769519792
This paper presents a logic based approach to hardware abstraction and composition based on the logic programming language Prolog. This is an attempt to satisfy the dual requirement of abstract hardware design and hardware efficiency. Central to this approach is a hardware description environment called HIDE, which provides more abstract and elegant hardware descriptions and compositions than are possible in traditional hardware description languages such as VHDL or Verilog. The environment enables highly scaleable and parameterised composition of blocks using a small set of constructors e.g. 'horizontal' and 'vertical' for 2D circuit abstractions and the novel 'above' constructor for 3D circuit compositions. It also generates pre-placed configurations in EDIF (and VHDL) format for Xilinx FPGAs.
The introduction of negation into logic programming brings the benefit of enhanced syntax and expressibility, but creates some semantical problems. Specifically, certain operators which are monotonic in the absence of...
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The introduction of negation into logic programming brings the benefit of enhanced syntax and expressibility, but creates some semantical problems. Specifically, certain operators which are monotonic in the absence of negation become non-monotonic when it is introduced, with the result that standard approaches to denotational semantics then become inapplicable. In this paper, we show how generalized metric spaces can be used to obtain fixed-point semantics for several classes of programs relative to the supported model semantics, and investigate relationships between the underlying spaces we employ. Our methods allow the analysis of classes of programs which include the acyclic, locally hierarchical, and acceptable programs, amongst others, and draw on fixed-point theorems which apply to generalized ultrametric spaces and to partial metric spaces. (C) 2002 Elsevier B.V. All rights reserved.
An executable computational logic can provide the desired bridge between formal system properties and formal methods to verify them on the one hand, and executable models of system designs based on programming languag...
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ISBN:
(纸本)0769519237
An executable computational logic can provide the desired bridge between formal system properties and formal methods to verify them on the one hand, and executable models of system designs based on programming languages on the other. However, not all such logics are equally well suited for the task. This paper gives some requirements that seem important for a computational logic to be suitable in practice, and discusses the experience with rewriting logic, its Maude language implementation, and its formal tool environment, concluding that they seem to meet well those requirements.
A number of ontology based systems have been developed that support typical knowledge management tasks. At the moment almost all of these systems, however, rely on a number of assumptions about the nature of environme...
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