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子句型自相容缺省理论的扩张 总被引:2,自引:0,他引:2
自相容缺省理论是一种颇具优良性质的特殊缺省理论,从子句着手是一般逻辑揄常用的方法,文中Reiter缺省理论和张明义的自相容缺省的理论的研究基础上,进一步研究了子句型闭自相容缺省理论,文中首先给出了自相容缺省理论的扩张个数的单调性定理,然后将Reter关于正规缺省理论的证明论推广到自相容缺省理论,得出了自相容缺省理论的缺省证明、自顶向下缺省证明和信念个性的相关定理。 相似文献
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1 引言缺省理论自1980年Reiter提出之后,已成为非单调推理的热点。在缺省逻辑中,扩张的概念至为重要。Reiter对特殊的缺省理论——正规缺省理论做了许多研究,并得出了一些漂亮的结果。Etherington给出了生成任意有穷有序半正规缺省理论的扩张的程序。张明义提出缺省的一种子类——自相容缺省理 相似文献
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苏开乐 《计算机工程与科学》1998,20(4):37-41
D.W.Etherington提出了一类总是有扩充的缺省理论,即有限有序缺省理论,同时使用接连近似的方法给出产生这类缺省理论的所有扩充的算法,并证明该算法对有限有序网络缺省理论总是收敛到一扩充。本文首先举例说明D.W.Etheringtond的算法对一般的有限有序缺省理论并非总是收敛,然后给出了该算法对
对一般的有限有序缺省理论收敛的一个充分条件。 相似文献
对一般的有限有序缺省理论收敛的一个充分条件。 相似文献
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基于模态缺省理论,建立多Agent系统的模态缺省逻辑,给出了每个主体 对应的模态缺省理论 的新知识和知识冲突的概念及其意义,主要讨论在多Agent环境下,当一个Agent的知识不足以完成推理时,可以从其它Agent处获得新的知识,从而对自身的信念集进行更新。当Wi发生变化(如遇到新的知识或出现与原信念集冲突的知识)时扩充Ei的性质和变化规律,提出了获取新扩充的较简单的求解方法,并证明了相关的定理,给出了多Agent系统的关于知识的一个动态描述过程。 相似文献
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本文在相信逻辑中引入相信解释与相信模的概念,从语义上把相信逻辑改造成非单调逻辑。一个缺省理论可以直接转换成一个相信逻辑理论,本文中证明了一个缺省理论外延的模集就是对应相信理论的模,从而为缺省理论提供了一种简便的语义。 相似文献
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本文在布尔环重量写系统中研究了缺省逻辑。一个缺省理论等价于一个布尔环方程组。本文还分析了命题缺省理论外延的结构,证明了一个缺省理论的外延的模型集合就是对应的布尔环方程组的极大缺省解,从而为确定缺省理论的外延提供了一种简便实用的方法。 相似文献
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本文建立子基于缺省理论的时态逻辑公式演绎系统。演绎过程除了使用一阶逻辑理论外,还采用了缺省理论来处理用户说明以及系统中知识不完全的问题。这种演绎系统演绎公式的过程也就是生成的过程,只要被演绎的公式序列能描述待生成的程序即可。 相似文献
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This paper deals with the automation of reasoning from incomplete information by means of default logics. We provide proof procedures for default logics' major reasoning modes, namely, credulous and skeptical reasoning. We start by reformulating the task of credulous reasoning in default logics as deductive planning problems. This interpretation supplies us with several interesting and valuable insights into the proof theory of default logics. Foremost, it allows us to take advantage of the large number of available methods, algorithms, and implementations for solving deductive planning problems. As an example, we demonstrate how credulous reasoning in certain variants of default logic is implementable by means of a planning method based on equational logic programming. In addition, our interpretation allows us to transfer theoretical results, such as complexity results, from the field of planning to that of default logics. In this way, we have isolated two yet unknown classes of default theories for which deciding credulous entailment is polynomial.Our approach to skeptical reasoning relies on an arbitrary method for credulous reasoning. It does not strictly require rather the inspection of all extensions, nor does it strictly require the computation of entire extensions to decide whether a formula is skeptically entailed. Notably, our approach abstracts from an underlying credulous reasoner. In this way, it can be used to extend existing formalisms for credulous reasoning to skeptical reasoning.This author was a visiting professor at the University of Darmstadt while parts of this work were being carried out. This author also acknowledges support from the Commission of the European Communities under grant no. ERB4001GT922433. 相似文献
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缺省推理中的三个定理 总被引:1,自引:1,他引:0
本文证明了缺省推理中的三个定理.定理1表明了缺省推理的非单调性这一特点.定理2的实际意义在于,在一个封闭规范缺省理论(D,W)中,只要W能推出D中某些缺省的结论,则可以把这样的缺省规则从理论中删除,所得到的较小的缺省理论其延伸仍与原来缺省理论一样.尤其是若W能推出D中所有的缺省规则结论,则(D,W)的延伸就是W,这就是本文推论的结论. 相似文献
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论述了Dempster_Shafer理论表示不确定性的理论与方法,指出不同的专业领域对不确定性问题的求解更多地依赖于专家的经验与常识。同时,给出基于一种特殊的概率分配函数的Dempster_Shafer理论的推理方法,并依此推理方法在智能化遥感分类系统中作了应用性验证;最后指出时态Dempster_Shafer理论是今后智能化遥感动态监测领域的一个重要研究方向。 相似文献
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Xi-ShunZhao 《计算机科学技术学报》2004,19(3):0-0
In this paper, the class of regular disjunction-free default theories is introduced and investigated.A transformation from regular default theories to normal default theories is established. The initial theory andthe transformed theory have the same extensions when restricted to old variables. Hence, regular default theoriesenjoy some similar properties (e.g., existence of extensions, semi-monotonicity) as normal default theories. Then,a new algorithm for credulous reasoning of regular theories is developed. This algorithm runs in a time not morethan 0(1.45~n), where n is the number of defaults. In case of regular prerequisite-free or semi-2CNF defaulttheories, the credulous reasoning can be solved in polynomial time. However, credulous reasoning for semi-Horndefault theories is shown to be NP-complete although it is tractable for Horn default theories. Moreover, skepticalreasoning for regular unary default theories is co-NP-complete. 相似文献
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Kurt Konolige 《Annals of Mathematics and Artificial Intelligence》1994,11(1-4):97-135
We present a theory of default reasoning that is specifically targeted to causal domains. These domains encompass a wide variety of current applications of default reasoning, but here we concentrate on model-based diagnosis. The theory is unique in that it integrates a formal notion of causality with nonmonotonic reasoning techniques based on default logic and abduction. The main structure of the theory is a default causal net (DCN) representing the causal connections among propositions in the domain. The causal net provides a framework for the two nonmonotonic reasoning techniques of assuming defaults and generating explanations for observations, allowing them to be combined in a principled way. 相似文献