一种可扩展型CLP系统的统一建模方法

约束推理是人工智能中主要组成部分之一,可以解决实际优化调度和规划过程中的约束求解问题。这里在解释了约束逻辑程序设计的原理和过程基础上,打破封闭式约束逻辑程序设计系统,从软件工程上采用统一建模语言,提出一种新的开放的可扩展型约束逻辑程序设计结构系统。为实现可扩展的约束推理搜索系统,引进UML建模语言中用例图、类图和协作图。在建模基础上详细说明了可扩展约束逻辑程序设计中数学模型,搜索引擎和搜索驱动三者间的关系以及它们内部的工作内容。最后在描述系统结构后,提出了可扩展的内容。根据扩展因素,外界为满足更多的需要可扩展本系统的约束过滤器。     

Reasoning Processes in Propositional Logic

We conducted a computer-based psychological experiment in which a random mix of 40 tautologies and 40 non-tautologies were presented to the participants, who were asked to determine which ones of the formulas were tautologies. The participants were eight university students in computer science who had received tuition in propositional logic. The formulas appeared one by one, a time-limit of 45 s applied to each formula and no aids were allowed. For each formula we recorded the proportion of the participants who classified the formula correctly before timeout (accuracy) and the mean response time among those participants (latency). We propose a new proof formalism for modeling propositional reasoning with bounded cognitive resources. It models declarative memory, visual memory, working memory, and procedural memory according to the memory model of Atkinson and Shiffrin and reasoning processes according to the model of Newell and Simon. We also define two particular proof systems, T and NT, for showing propositional formulas to be tautologies and non-tautologies, respectively. The accuracy was found to be higher for non-tautologies than for tautologies (p < .0001). For tautologies the correlation between latency and minimum proof length in T was .89 and for non-tautologies the correlation between latency and minimum proof length in NT was .87.     

Timing Analysis of Combinational Circuits in Intuitionistic Propositional Logic

Classical logic has so far been the logic of choice in formal hardware verification. This paper proposes the application of intuitionistic logic to the timing analysis of digital circuits. The intuitionistic setting serves two purposes. The model-theoretic properties are exploited to handle the second-order nature of bounded delays in a purely propositional setting without need to introduce explicit time and temporal operators. The proof-theoretic properties are exploited to extract quantitative timing information and to reintroduce explicit time in a convenient and systematic way.We present a natural Kripke-style semantics for intuitionistic propositional logic, as a special case of a Kripke constraint model for Propositional Lax Logic (Information and Computation, Vol. 137, No. 1, 1–33, 1997), in which validity is validity up to stabilisation, and implication comes out as boundedly gives rise to. We show that this semantics is equivalently characterised by a notion of realisability with stabilisation bounds as realisers. Following this second point of view an intensional semantics for proofs is presented which allows us effectively to compute quantitative stabilisation bounds.We discuss the application of the theory to the timing analysis of combinational circuits. To test our ideas we have implemented an experimental prototype tool and run several examples.     

Semantics of looping programs in Propositional Dynamic Logic

Standard and nonstandard models of Propositional Dynamic Logic differ in their interpretation of loops. In Standard models, a loop is interpreted as the Kleene closure of the interpretation of its loop body; in nonstandard (Loop Invariant) models, a loop is interpreted as a program which preserves invariant assertions over the loop body.In this paper we show that both interpretations are adequate to represent loops in PDL. We demonstrate this in two ways: First we note that Standard and Loop Invariant models are distinct but not distinguishable within PDL. Second, we show that the class of Loop Invariant models is complete with respect to the Segerberg axiomatization of PDL. Since completeness of the class of Loop Invariant models implies completeness of the class of Standard models, Standard models are also complete with respect to this axiomatization.The research reported here was supported in part by NSF Grants MCS77-02474 and MCS80-05387. Most of the results in this paper were announced in A Completeness Technique forD-axiomatizable Semantics presented at the 11th Annual ACM Symposium on the Theory of Computing in May, 1979.     

开放教育排课问题约束分析与数学建模

高等教育教学管理信息化是高校提高竞争力的关键因素。开放教育作为一种成人性质的高等教育类型,教育资源的非均衡配置限制了开放教育的发展。高校排课问题是一个多目标、多约束的资源与时空组合优化问题。排课问题的求解能够实现教育资源优化配置。本文基于开放教育的特点与教育资源的需求情况,以排课问题为切入点,分析排课问题的各种约束条件,利用数学方法构造求解排课问题的数学模型,为后续智能排课系统的设计与开发提供算法基础。     

Deciding Effectively Propositional Logic Using DPLL and Substitution Sets

We introduce a DPLL calculus that is a decision procedure for the Bernays-Schönfinkel class, also known as EPR. Our calculus allows combining techniques for efficient propositional search with data-structures, such as Binary Decision Diagrams, that can efficiently and succinctly encode finite sets of substitutions and operations on these. In the calculus, clauses comprise of a sequence of literals together with a finite set of substitutions; truth assignments are also represented using substitution sets. The calculus works directly at the level of sets, and admits performing simultaneous constraint propagation and decisions, resulting in potentially exponential speedups over existing approaches.     

Incremental search in Constraint Logic Programming

Incremental search consists of adding new constraints or deleting old ones once a solution to a search problem has been found. Although incremental search is of primary importance in application areas such as scheduling, planning, trouble shooting, and interactive problem-solving, it is not presently supported by logic programming languages and little research has been devoted to this topic. This paper presents a scheme to deal efficiently with incremental search problems. The scheme allows the incremental addition and deletion of constraints and is based on re-execution, using parts of computation paths stored during previous computations. The scheme has been implemented as part of the constraint logic programming language CHIP and applied to practical problems. It has shown arbitrarily large (i.e. unbounded) speedups compared with previous approaches on practical problems.     

命题模态逻辑S5系统中并行推理方法

S5系统是一类知识表示能力和处理能力都较强的模态公理系统,它是认知逻辑、信念逻辑等非经典逻辑理论的基础。根据Kripke语义模型以及S5系统中部分公理,对命题模态逻辑S5公理系统的性质进行了较为深入的研究,并对S5系统中一类具有代表性的标准模态子句集的特性进行了分析,提出了一种基于扩展规则方法的命题模态逻辑推理算法(propositional modal clausal reasoning based on novel extension rule,PMCRNER)。针对朴素算法时间复杂度较高的问题,利用任务间潜在的关联性对算法同时进行了粗粒度与细粒度并行化,提出了并行算法PPMCRNER(parallel PMCRNER)理论框架,并且与基本算法进行了对比。实验结果表明,PPMCRNER算法在不可满足的子句集上的推理具有良好的加速比,为高时间复杂性的模态推理方法的进一步研究提供了一种可行方案。     

基于UML的销售系统业务流程分析与仿真

以销售业务流程为例,借鉴面向对象的系统分析方法,结合流程重组理论,对基于UML的业务流程分析方法进行研究。首先通过用例图来描述系统功能,给出系统总体框架;然后运用状态图、活动图和顺序图详细描述系统的动态行为以及对象间的交互关系,通过分析业务流程的合理性,可得到有效的系统流程重组方案。最后通过SIMPROCESS仿真工具模拟重组前后的业务流程,通过对仿真结果的分析,表明该方法有助于业务的优化和运作效率的提高。     

Static and Dynamic Slicing of Constraint Logic Programs

Slicing is a program analysis technique originally developed for imperative languages. It facilitates understanding of data flow and debugging.This paper discusses slicing of Constraint Logic Programs. Constraint Logic Programming (CLP) is an emerging software technology with a growing number of applications. Data flow in constraint programs is not explicit, and for this reason the concepts of slice and the slicing techniques of imperative languages are not directly applicable.This paper formulates declarative notions of slice suitable for CLP. They provide a basis for defining slicing techniques (both dynamic and static) based on variable sharing. The techniques are further extended by using groundness information.A prototype dynamic slicer of CLP programs implementing the presented ideas is briefly described together with the results of some slicing experiments.     

Conceptual Modeling and Querying in Multimedia Databases

In this paper, we discuss some design principles that will aid in the design and querying of multimedia databases. We use an object-relational data model and argue that multimedia objects should normally have a special attribute called core which stores the real object itself in contrast to the abstraction which is reflected in the rest of the attributes. We present an extension to the ER Diagram that takes advantage of the core notion to facilitate design of multimedia databases. We discuss some desirable features in a query language for multimedia databases: simplifications like the use of path expressions and implicit use of functions (methods) as attributes, and explicit specification of the display layout and format either at the data definition level or query specification level. To materialize this last feature, we propose a display specification extension to SQL (SQL+D) that we have implemented.     

Efficient Interval Linear Equality Solving in Constraint Logic Programming

Existing interval constraint logic programming languages, such as BNR Prolog, work under the framework of interval narrowing and are deficient in solving systems of linear constraints over real numbers, which constitute an important class of problems in engineering and other applications. In this paper, we suggest to separate linear equality constraint solving from inequality and non-linear constraint solving. The implementation of an efficient interval linear constraint solver, which is based on the preconditioned interval Gauss-Seidel method, is proposed. We show how the solver can be adapted to incremental execution and incorporated into a constraint logic programming language already equipped with a non-linear solver based on interval narrowing. The two solvers share common interval variables, interact and cooperate in a round-robin fashion during computation, resulting in an efficient interval constraint arithmetic language CIAL. The CIAL prototypes, based on CLP(R), are constructed and compared favorably against several major interval constraint logic programming languages.     

Syntax and Semantics for a Fuzzy Temporal Constraint Logic

In this paper we establish the relationship between the syntax and semantics of a fuzzy temporal constraint logic (FTCL) proposed by Cárdenas et al. FTCL enables us to express interrelated events by means of fuzzy temporal constraints. Moreover, it provides a resolution principle for performing inferences which take these constraints into account. FTCL is compatible with the theoretical temporal reasoning model proposed by Marín et al. – the Fuzzy Temporal Constraint Networks (FTCN). The main contributions of this paper are, on the one hand, the proofs of the FTCL-deduction and the FTCL-refutation theorems, and, on the other, the proof of the soundness of the refutation by resolution in this formal system, together with an exhaustive study of its completeness.     

本体在概念建模中的应用研究

概念建模是指创建概念模型的行为,这些模型用来描述问题,与具体用于解决问题的技术和策略独立无关.在过去数十年中,大量概念建模方法和工具纷纷涌现,许多理论如本体论、语言学和认知学的引入,增强了概念建模的理论基础,基于本体的概念建模研究得到了充分重视.探讨了基于本体的概念建模理论、概念建模语言中本体的作用、上层本体与领域本体的关系;对基于本体的概念模型以及本体语言及其逻辑基础在概念模型的一致性检测的应用进行了研究.     

支持概念设计的特征手势建模

给出了特征手势的概念并且建立了特征手势库,描述了基于特征手势的建模过程;进一步讨论了特征手势内部的约束建立和求解算法以及上下文感知技术,通过与传统建模和交互方式的对比,验证了特征手势建模的方便性．文中算法以用户为中心,给出了自然简便的设计工具,改善了人机交互方式．