共查询到19条相似文献,搜索用时 109 毫秒
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模糊时态数据库关系代数演算规则分析 总被引:1,自引:0,他引:1
为了解决时态数据库对客观世界更符合实际抽象描述,能有效表示和处理复杂对象的模糊时态特性,从基本模糊时态数据模型入手,定义了一系列模糊时态关系操作元素,并论证了模糊时态区间关系代数的语法和语义,建立了一个能描述模糊时态信息的关系代数理论体系.避免了时态数据库不能提供表达模糊时态信息的环境设施,也增强了现有的时态数据库描述模糊事物特性的能力. 相似文献
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间断区间时态逻辑的语义 总被引:1,自引:0,他引:1
区间逻辑不能模拟自然语言中与,或,非时态关系,其公理系统的完备性不易保证。我们建立的间断区间时态知脚注可以克服区间逻辑的上述缺点,本文给出了间断区间逻辑的语法,语义及公理,即描述了间断区间时态逻辑的语义。 相似文献
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周巢尘 《计算机应用与软件》1984,(2)
前文“结构式时态语义”中定义了程序语言的一种时态语义,这种语义是语法引导的(Syntax Directed),保持语言的结构。本文中讨论在这种语义基础上的程序推理问题。因为这是时态语义,故在程序描述中可使用时态逻辑的丰富的表达力;又因为它是结构式的,故关于各种语句已有的推理方法,都可以翻译为时态逻辑中的定理,随意应用。 相似文献
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时态描述逻辑将描述逻辑的刻画能力引入到命题时态逻辑中,适合于在语义Web环境下对相关系统的时态性质进行刻画.为了对这些时态性质进行高效的验证,在ALC-LTL的基础上研究了时态描述逻辑的模型检测问题.一方面,使用时态描述逻辑ALC-LTL公式来表示待验证的时态规范;另一方面,在对系统建模时借助描述逻辑ALC对领域知识进行刻画.针对上述扩展后得到的模型检测问题,提出了基于自动机的ALC-LTL模型检测算法.模型检测算法由3个阶段组成:首先将时态规范的否定形式和系统模型分别构造成标记büchi自动机;接下来构造这两个自动机的乘积自动机,并将关于ALC的推理机制融入到乘积自动机的构造过程中;最后对该乘积自动机进行判空检测.与LTL模型检测相比,时态描述逻辑ALC-LTL的模型检测引入了描述逻辑的刻画和推理机制,可以在语义Web环境下对语义Web服务等复杂系统的时态性质进行刻画和验证. 相似文献
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一种面向DRM的责任授权模型及其实施框架 总被引:2,自引:0,他引:2
针对现有的DRM(digital rights management)机制缺乏真正的责任描述和实施能力问题,提出一种应用于DRM的责任授权模型及其实施框架.该模型基于分布式时态逻辑和Active-U-Datalog语法规则,具有表达事件驱动、时间驱动和责任补偿等各类责任授权的语义能力,并具有良好的可实施性.对该模型的语法语义进行了分析和说明,描述了责任实施机制,并对该模型的实现、应用和表达力进行了说明和示例.该模型提高了DRM系统对数据使用控制的灵活性和能力. 相似文献
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针对现有的分布式逻辑语言缺乏完整时态表达力等问题,将分布式时态逻辑谓词引入Datalog规则,提出TU-Datalog语言。该语言通过融入U-Datalog的非即时性更新语义,形成完全声明式具有强大时态表达力的逻辑编程语言和环境。通过扩展U-Datalog逻辑固定点语义,提出TU-Datalog语言的固定点时态演化规则,并对该语言的语法、语义、评价算法进行了研究,最后对该语言的应用做了说明和示例。 相似文献
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Davide Bresolin Angelo Montanari Guido Sciavicco 《Journal of Automated Reasoning》2007,38(1-3):173-199
Propositional interval temporal logics are quite expressive temporal logics that allow one to naturally express statements
that refer to time intervals. Unfortunately, most such logics turn out to be (highly) undecidable. In order to get decidability,
severe syntactic or semantic restrictions have been imposed to interval-based temporal logics to reduce them to point-based
ones. The problem of identifying expressive enough, yet decidable, new interval logics or fragments of existing ones that
are genuinely interval-based is still largely unexplored. In this paper, we focus our attention on interval logics of temporal
neighborhood. We address the decision problem for the future fragment of Neighborhood Logic (Right Propositional Neighborhood
Logic, RPNL for short), and we positively solve it by showing that the satisfiability problem for RPNL over natural numbers
is NEXPTIME-complete. Then, we develop a sound and complete tableau-based decision procedure, and we prove its optimality. 相似文献
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Hierarchies of modal and temporal logics with reference pointers 总被引:1,自引:1,他引:0
Valentin Goranko 《Journal of Logic, Language and Information》1996,5(1):1-24
We introduce and study hierarchies of extensions of the propositional modal and temporal languages with pairs of new syntactic devices: point of reference-reference pointer which enable semantic references to be made within a formula. We propose three different but equivalent semantics for the extended languages, discuss and compare their expressiveness. The languages with reference pointers are shown to have great expressive power (especially when their frugal syntax is taken into account), perspicuous semantics, and simple deductive systems. For instance, Kamp's and Stavi's temporal operators, as well as nominals (names, clock variables), are definable in them. Universal validity in these languages is proved undecidable. The basic modal and temporal logics with reference pointers are uniformly axiomatized and a strong completeness theorem is proved for them and extended to some classes of their extensions. 相似文献
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Tomi Janhunen 《Annals of Mathematics and Artificial Intelligence》1999,27(1-4):79-128
This paper concentrates on comparing the expressive powers of five non‐monotonic logics that have appeared in the literature.
For this purpose, the concept of a polynomial, faithful and modular (PFM) translation function is adopted from earlier work
by Gottlob, but a weaker notion of faithfulness is proposed. The existence of a PFM translation function from one non‐monotonic
logic to another is interpreted to indicate that the latter logic is capable of expressing everything that the former logic
does. Several translation functions are presented in the paper and shown to be PFM. Moreover, it is shown that PFM translation
functions are impossible in certain cases, which indicates that the expressive powers of the logics involved differ strictly.
The comparisons made in terms of PFM translation functions give rise to an exact classification of non‐monotonic logics, which
is then named as the expressive power hierarchy (EPH) of non‐monotonic logics. Three syntactically restricted variants of
default logic are also analyzed, and EPH is refined accordingly. Most importantly, the classes of EPH indicate some astonishing
relationships in light of earlier results on the expressive power of non‐monotonic logics presented by Gottlob as well as
Bonatti and Eiter: Moore’s autoepistemic logic and prerequisite‐free default logic are of equal expressive power and less
expressive than Reiter’s default logic and Marek and Truszczyński’s strong autoepistemic logic.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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Many temporal logics have been suggested as branching time specification formalisms during the past 20 years. These logics were compared against each other for their expressive power, model checking complexity, and succinctness. Yet, unlike the case for linear time logics, no canonical temporal logic of branching time was agreed upon. We offer an explanation for the multiplicity of temporal logics over branching time and provide an objective quantified yardstick to measure these logics. We define an infinite hierarchy BTLk of temporal logics and prove its strictness. We examine the expressive power of commonly used branching time temporal logics. We show that CTL* has no finite base, and that almost all of its many sublogics suggested in the literature are inside the second level of our hierarchy. We introduce new Ehrenfeucht–Fraissé games on trees and use them as our main tool to prove inexpressibility. 相似文献
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时序认知逻辑是由时序逻辑和认知逻辑组合而成的逻辑,主要应用于多主体系统的规范定义.大多数时序认知逻辑是基于CTL的,表达能力有限.并且已知的一些模型检查算法存在内存不足和状态爆炸等问题.讨论了基于CTL*的时态认知逻辑cTL*K的语法、语义和模型,它能够在表达力很强的时态逻辑CTL*基础上描述智能体的知识、目标等意向特征.并给出了CTL*K的模型检查算法,其核心思想就是将CTL*K公式的检查问题转化为CTL*公式的模型检查问题,可以使检查的系统规模得以大幅度提高.并且将算法编码后容易集成到NuSMV模型检查器. 相似文献
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Davide Bresolin Dario Della Monica Angelo Montanari Guido Sciavicco 《Annals of Mathematics and Artificial Intelligence》2014,71(1-3):11-39
Decidability and complexity of the satisfiability problem for the logics of time intervals have been extensively studied in the recent years. Even though most interval logics turn out to be undecidable, meaningful exceptions exist, such as the logics of temporal neighborhood and (some of) the logics of the subinterval relation. In this paper, we explore a different path to decidability: instead of restricting the set of modalities or imposing severe semantic restrictions, we take the most expressive interval temporal logic studied so far, namely, Venema’s CDT, and we suitably limit the negation depth of modalities. The decidability of the satisfiability problem for the resulting fragment, called CDTBS, over the class of all linear orders, is proved by embedding it into a well-known decidable quantifier prefix class of first-order logic, namely, Bernays-Schönfinkel class. In addition, we show that CDTBS is in fact NP-complete (Bernays-Schönfinkel class is NEXPTIME-complete), and we prove its expressive completeness with respect to a suitable fragment of Bernays-Schönfinkel class. Finally, we show that any increase in the negation depth of CDTBS modalities immediately yields undecidability. 相似文献
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Specification diagrams (SD's) are a novel form of graphical notation for specifying open distributed object systems. The design goal is to define notation for specifying message-passing behavior that is expressive, intuitively understandable, and that has formal semantic underpinnings. The notation generalizes informal notations such as UML's Sequence Diagrams and broadens their applicability to later in the design cycle. Specification diagrams differ from existing actor and process algebra presentations in that they are not executable per se; instead, like logics, they are inherently more biased toward specification. In this paper we rigorously define the language syntax and semantics and give examples that show the expressiveness of the language, how properties of specifications may be asserted diagrammatically, and how it is possible to reason rigorously and modularly about specification diagrams. 相似文献
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基于本体语言OWL的模糊扩展 总被引:2,自引:1,他引:1
本体能够对特定领域的概念、术语以及关系提供一种形式化的描述方法.尽管本体在知识表示上有很强的能力,但是有一个缺陷,即不能表达不确定和不精确的信息.而这些信息在语义网和多媒体应用中,又是至关重要的.针对模糊信息的本体表示问题,本文对本体语言OWL DL进行了基于模糊逻辑的扩展,给出了形式化的语法和语义,并通过一个实例说明了该方法在表达能力上的灵活性. . 相似文献
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First-order temporal logic, the extension of first-order logic with operators dealing with time, is a powerful and expressive formalism with many potential applications. This expressive logic can be viewed as a framework in which to investigate problems specified in other logics. The monodic fragment of first-order temporal logic is a useful fragment that possesses good computational properties such as completeness and sometimes even decidability. Temporal logics of knowledge are useful for dealing with situations where the knowledge of agents in a system is involved. In this paper we present a translation from temporal logics of knowledge into the monodic fragment of first-order temporal logic. We can then use a theorem prover for monodic first-order temporal logic to prove properties of the translated formulas. This allows problems specified in temporal logics of knowledge to be verified automatically without needing a specialized theorem prover for temporal logics of knowledge. We present the translation, its correctness, and examples of its use.
Partially supported by EPSRC project: Analysis and Mechanisation of Decidable First-Order Temporal Logics (GR/R45376/01). 相似文献