We study existential and universal quantification over quantifiers, i.e. quantification where the objects quantified over are Lindstrom quantifiers. First we consider the fragment where only existential quantification...
详细信息
Layout analysis is the process of extracting a hierarchical structure describing the layout of a page. In the system WISDOM++, the layout analysis is performed in two steps: firstly, the global analysis determines pos...
详细信息
ISBN:
(纸本)1577351894
Layout analysis is the process of extracting a hierarchical structure describing the layout of a page. In the system WISDOM++, the layout analysis is performed in two steps: firstly, the global analysis determines possible areas containing paragraphs, sections, columns, figures and tables, and secondly, the local analysis groups together blocks that possibly fall within the same area. The result of the local analysis process strongly depends on the quality of the results of the first step. We investigate the possibility of supporting the user during the correction of the results of the global analysis. This is done by automatically generating training examples of action selections from the sequence of user actions, and then by learning action selection rules for layout correction. Rules are expressed as a logic program whose induction demands the careful application of ILP techniques. Experimental results on a set of multi-page documents shed evidence on the difficulty of the learning task tackled and pose new problems in learning control rules for adaptive interfaces.
A relational database may not satisfy certain integrity constraints (ICs) for several reasons. However most likely most of the information in it is still consistent with the ICs. The answers to queries that are consis...
详细信息
ISBN:
(纸本)3540009574
A relational database may not satisfy certain integrity constraints (ICs) for several reasons. However most likely most of the information in it is still consistent with the ICs. The answers to queries that are consistent with the ICs can be considered sematically correct answers, and are characterized [2] as ordinary answers that can be obtained from every minimally repaired version of the database. In this paper we address the problem of specifying those repaired versions as the minimal models of a theory written in Annotated Predicate logic [27]. It is also shown how to specify database repairs using-disjunctive logic program with annotation arguments and a classical stable model semantics. Those programs are then used to compute consistent answers to general first order queries. Both the annotated logic and the logic programming approaches work for any set of universal. and referential integrity constraints. Optimizations of the logic programs are also analyzed.
We study here schedulers for a class of rules that naturally arise in the context of rule-based constraint programming. We systematically derive a scheduler for them from a generic iteration algorithm of Apt. We apply...
详细信息
ISBN:
(纸本)9781581136241
We study here schedulers for a class of rules that naturally arise in the context of rule-based constraint programming. We systematically derive a scheduler for them from a generic iteration algorithm of Apt. We apply this study to so-called membership rules of Apt and Monfroy. This leads to an implementation that yields for these rules a considerably better performance than their execution as standard CHR rules.
We propose a practical path-based framework for deriving and simplifying source-tracking information for term unification in the empty theory. Such a framework is useful for debugging unification-based systems, includ...
详细信息
Strategy annotations are used in eager programming languages (e.g., OBJ2, OBJ3, CafeOBJ, and Maude) for improving efficiency and/or reducing the risk of nontermination. Syntactically, they are given either as lists of...
详细信息
Induction of the effects of actions considered here consists in learning an action description of a dynamic system from evidence on its behavior. General logic-based induction methods can deal with this problem but, u...
详细信息
ISBN:
(纸本)9783540399179
Induction of the effects of actions considered here consists in learning an action description of a dynamic system from evidence on its behavior. General logic-based induction methods can deal with this problem but, unfortunately, most of the solutions provided have the frame problem. To cope with the frame problem induction under suitable nonmonotonic formalisms has to be used, though this kind of induction is not well understood yet. We propose an alternative method that relies on the identification of a monotonic induction problem whose solutions correspond one-to-one to those of the original problem without the frame problem. From this result induction of the effects of actions can be characterized under current monotonic induction methods.
Default logic is one of the best known and most studied of the approaches to nonmonotonic reasoning. Subsequently, several variants of default logic have been proposed to give systems with properties differing from th...
详细信息
ISBN:
(纸本)3540404945
Default logic is one of the best known and most studied of the approaches to nonmonotonic reasoning. Subsequently, several variants of default logic have been proposed to give systems with properties differing from the original. In this paper we show that these variants are in a sense superfluous, in that for any of these variants of default logic, we can exactly mimic the behaviour of a variant in standard default logic. We accomplish this by translating a default theory under a variant interpretation into a second default theory wherein the variant interpretation is respected.
In previous papers, we have presented a logic-based framework for merging structured news reports. Structured news reports are XML documents, where the text entries are restricted to individual words or simple phrases...
详细信息
In previous papers, we have presented a logic-based framework for merging structured news reports. Structured news reports are XML documents, where the text entries are restricted to individual words or simple phrases, such as names and domain-specific terminology, and numbers and units. We assume structured news reports do not require natural language processing. In this paper, we present prepositional fusion rules as a way of implementing logic-based fusion for structured news reports. Fusion rules are a form of scripting language that define how structured news reports should be merged. The antecedent of a fusion rule is a call to investigate the information in the structured news reports and the background knowledge, and the consequent of a fusion rule is a formula specifying an action to be undertaken to form a merged report. It is expected that a set of fusion rules is defined for any given application. We give the syntax and mode of execution for fusion rules, and explain how the resulting actions give a merged report.
We investigate rule dependency graphs and their colorings for characterizing the computation of answer sets of logic programs. We start from a characterization ofanswer sets in terms oftotally colored dependency graph...
详细信息
We investigate rule dependency graphs and their colorings for characterizing the computation of answer sets of logic programs. We start from a characterization ofanswer sets in terms oftotally colored dependency graphs. To a turn, we develop a series ofoperational characterizations ofanswer sets in terms ofoperators on partial colorings. In analogy to the notion ofa derivation in proof theory, our operational characterizations are expressed as (non-deterministically formed) sequences ofcolorings, turning an uncolored graph into a totally colored one. This results in an operational framework in which different combinations ofoperators result in different formal properties. Among others, we identify the basic strategy employed by the noMoRe system and justify its algorithmic approach. Also, we distinguish Fitting's and well-founded semantics.
暂无评论