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1.
黄东斌  李磊 《软件学报》1996,7(12):728-734
纯Datalog的唯一模型定理在Datalog-Not程序中不成立,因此,在Datalog-Not程序的所有Herbrand模型中,必须有一种模型的选择标准来确定程序的语义.完美模型关系是一种合理的选择标准.然而,由于完美模型的复杂性阻止了它的发展.本文分析了完美模型,通过有向图,给出了有完美模型的充要条件,并且给出构造算法及其正确性证明.本文得到的结果是:对任一自反有向图G,都能构造一个Datalog-Not程序P,使得P的完美模型图与G同构.  相似文献   

2.
张成洪  施伯乐 《软件学报》1996,7(A00):38-44
上文介绍了面向对象数据库系统FOOD的推进查询语言O-D本文继续讨论对O-D程序的几种变换,并证明这些变换是语义等价的,从而证明了对于一个O-Datalog程序,可以为它构造一个相应的Datalog程度,并能利用该Datalog程序对原程序进行计值,最后本文还给出了对O-Datalog程序计值的算法。  相似文献   

3.
面向对象数据库的推理查询语言   总被引:3,自引:1,他引:2  
张成洪  施伯乐 《软件学报》1996,7(A00):30-37
本文基于复旦大学开发的一个面向对象数据库系统FOOD,提出一种推理查询语言O-Datalog,语言能方便地表达对面向对象数据的各种查询和推理要求,它可以转换 Datalog形式,能运用各种高效计值算法,比其它一些基于非Horn子句逻辑的语言更易于O-Datalog在形式上是一种Dataog的扩充,本文着重介绍其语法和语义。  相似文献   

4.
讨论Datalog线性链规则递归查询问题,利用数据库图可将它归约为普通传递闭包问题。  相似文献   

5.
一个支持并行的可视化编程环境的设计与实现   总被引:1,自引:0,他引:1  
柳颖  谢立 《微型计算机》1996,16(6):47-50
本文阐述了可视化程序设计的特点,提出了一种基于程序流程图的可视化程序的设计思想,它不仅简化了用户程序设计,而且提供了开发并行程序的可视化方法,在上述思想的基础上本文设计了PDB-VPE,即ProgramDiagramBased-VisualProgrammingEnviroment,并加以实现。  相似文献   

6.
八数码问题是人工智能领域中的一个游戏难题,文章旨在介绍八数码问题以及基于图搜索算法的解决此类问题的一种启发式搜索算法-A^*算法。并依据传统的A^*算法用Delphi给出了一个八数码问题的演示程序。  相似文献   

7.
王家华  金祥意 《控制与决策》1998,13(2):173-176,172
为满足大型企业中产品零部件数据管理的需要,解决关系数据库所不能解决的递归查询问题,为微机关系数据库设计并实现了一个递归查询接口,该接口能够计算了Datalog逻辑程序,通过允许规划头部包含函数符号,使规则增加了数值计算能力。  相似文献   

8.
ADM的密钥程序重庆交通学院计算机系胡久永目前ADM在各公用机房中普遍使用,使硬盘上的各种软件和数据的安全有了保障。但若密码忘记了,特别上超级用户的密码忘记了,就无法进入加密的逻辑盘。本文提供一个简单的密钥程序,可以打开ADM盘的密锁。ADM软件将有...  相似文献   

9.
本文在ADL和DADL基础上发展了一种引入抽象数据类型的逻辑型和函数型程序变换语言,阐述了从逻辑型向函数型和从函数型向过程型程序的变换方法,并介绍了基于超文本技术的程序变换支撑系统。  相似文献   

10.
基于不变量的程序修复进化扩展模型*   总被引:1,自引:1,他引:0  
何加浪  张琨  孟锦  张宏 《计算机应用研究》2010,27(12):4533-4535
为了有效解决程序修复进化中搜索空间过大和正常功能牺牲的问题,提出了一种基于不变量约束的扩展的程序修复进化模型(extended repair evolutionary model,EREM),利用程序不变量约束对搜索空间进行划分和约简以降低消耗,通过使用表达程序正常功能的正测试用例学习的不变量约束(称为正不变量约束)来保证程序不牺牲正常的功能,在适应度函数的设计上考虑测试用例通过数的同时也考虑了正不变量约束的保持数,对于破坏正不变量约束的个体适应度给予一定的惩罚值。最后通过实验对模型进行了验证,结果表明了  相似文献   

11.
The branching-time transformation technique has proven to be an efficient approach for implementing functional programming languages. In this paper we demonstrate that such a technique can also be defined for logic programming languages. More specifically, we first introduce Branching Datalog, a language that can be considered as the basis for branching-temporal deductive databases. We then present a transformation algorithm from Chain Datalog programs to the class of unary Branching Datalog programs with at most one IDB atom in the body of each clause. In this way, we obtain a novel implementation approach for Chain Datalog, shedding at the same time new light on the power of branching-time logic programming.  相似文献   

12.
王云明  施伯乐 《软件学报》1997,8(9):641-646
为了提高DATALOG程序自底向上计值的效率,本文提出了把DATALOG规则分成若干个组,对这些组可以给出一个拓扑序列,而对同一个组内的各个规则可以给出一个激发序列,以此来有效地控制DATALOG程序自底向上计值时对规则的调度,从而提高计算效率.这一技术可以应用于传统的各种自底向上计算方法,本文绘出了半朴质(Semi-Naove)算法和良基模型(Well-Founded)的交替不动点算法(AlternatingFixPoint)的改进.改进后的算法比原算法在时间和空间效率上都有较大的提高.  相似文献   

13.
The key issue in normalization with respect to geometric transformation is how to obtain a consistent canonical form which remains unchanged for different geometric transformation related images. Due to ambiguities inherent in the specified normalization methods, more than one canonical form may occur during the normalization procedure. This causes difficulties in obtaining the expected invariant features or the transformation parameters through normalization. This paper aims to provide general schemes to analyze the ambiguity characteristics and to derive the ambiguity matrices through which ambiguities can be eliminated. Three kinds of ambiguities caused by the multi-roots of high-order polynomials, the symmetrical normalization constraints, and the reflection are addressed and solutions are provided to obtain a consistent canonical form for each kind of ambiguities.  相似文献   

14.
The paradigm of disjunctive logic programming(DLP)enhances greatly the expressive power of normal logic programming(NLP)and many(declarative)semantics have been defined for DLP to cope with various problems of knowledge representation in artificial intelligence.However,the expressive ability of the semantics and the soundness of program transformations for DLP have been rarely explored.This paper defines an immediate consequence operatro T^GP for each disjunctive program and shows that T^GP has the least and computable fixpoint Lft(P),Lft is,in fact,a program transformation for DLP,which transforms all disjunctive programs into negative programs.It is shown that Lft preserves many key semantics,including the disjunctive stable models,well-founded model,disjunctive argunent semantics DAS,three-valued models,ect.Thic means that every disjunctive program P has a unique canonical form Lft(P)with respect to these semantics.As a result,the work in this paper provides a unifying framework for studying the expressive ability of various semantics for DLP On the other hand,the computing of the above semantics for negative programs is ust a trivial task,therefore,Lft(P)is also an optimization method for DLP.Another application of Lft is to derive some interesting semantic results for DLP.  相似文献   

15.
Constraint Handling Rules (CHRs) are a high-level rule-based programming language commonly used to define constraint solvers. We present a method for automatic implication checking between constraints of CHR solvers. Supporting implication is important for implementing extensible solvers and reification, and for building hierarchical CHR constraint solvers. Our method does not copy the entire constraint store, but performs the check in place using a trailing mechanism. The necessary code enhancements can be done by automatic program transformation based on the rules of the solver. We extend our method to work for hierarchically organized modular CHR solvers. We show the soundness of our method and its completeness for a restricted class of canonical solver as well as for specific existing non-canonical CHR solvers. We evaluate our trailing method experimentally by comparing with the copy approach: runtime is almost halved.  相似文献   

16.
给出了Hamilton系统基于辛矩阵乘法的显式时不变正则变换和时变正则变换.引入含参变量的近似Hamilton系统,并以近似Hamilton系统为基础进行辛矩阵乘法的正则变换.正则变换保证了数值积分的保辛性质,而通过调整引入的参变量可保证能量在积分格点上守恒.实现了Hamilton系统即保辛又保能量的算法.  相似文献   

17.
The nested relational model allows relations that are not in first normal form. This paper gives an extension of Datalog rules for nested relations. In our approach, nested Datalog is a natural extension of Datalog introduced for the relational data model. A nested Datalog program has a hierarchical structure of rules and subprograms to manipulate relation values of nested relations. We introduce a new category of predicate symbols, the variable predicate symbols to refer to tuples of subrelations. The notion of soundness, safety and consistency is defined to avoid undesirable nested Datalog programs. The evaluation of nested Datalog is given in terms of the nested relational algebra. Finally, we relate the expressive power of nonrecursive nested Datalog to the power of nested relational algebra and safe nested tuple relational calculus.  相似文献   

18.
Temporal logic queries on Datalog and negated Datalog programs are studied, and their relationship to Datalog queries on these programs is explored. It is shown that, in general, temporal logic queries have more expressive power than Datalog queries on Datalog and negated Datalog programs. It is also shown that anexistential domain-independent fragment of temporal logic queries has the same expressive power as Datalog queries on negated Datalog programs with inflationary semantics. This means that for finite structures this class of queries has the power of the fixpoint logic.  相似文献   

19.
We study non-uniform constraint satisfaction problems definable in monadic Datalog stratified by the use of non-linearity. We show how such problems can be described in terms of homomorphism dualities involving trees of bounded pathwidth and in algebraic terms. For this, we introduce a new parameter for trees that closely approximates pathwidth and can be characterised via a hypergraph searching game.  相似文献   

20.
ContextThe role of formal specification in requirements validation and analysis is generally considered to be limited because considerable expertise is required in developing and understanding the mathematical proofs. However, formal semantics of a language can provide a basis for step-by-step execution of requirements specification by building an easy to use simulator to assist in requirements elicitation, validation and analysis.ObjectiveThe objective of this paper is to illustrate the usefulness of a simulator that executes requirements and captures system states as rules and facts in a database. The database can then be queried to carry out analysis after all the requirements have been executed a given number of timesMethodBehavior Trees (BTs)1 are automatically translated into Datalog facts and rules through a simulator called SimTree. The translation process involves model-to-model (M2M) transformation and model-to-text (M2T) transformation which automatically generates the code for a simulator called SimTree. SimTree on execution produces Datalog code. The effectiveness of the simulator is evaluated using the specifications of a published case study – Ambulatory Infusion Pump (AIP)2.ResultsThe BT specification of the AIP was transformed into SimTree code for execution. The simulator produced a complete state-space for a predetermined number of runs in the form of Datalog facts and rules, which were then analyzed for various properties of interest like safety and liveness.ConclusionQueries of the resultant Datalog code were found to be helpful in identifying defects in the specification. However, probability values had to be manually assigned to all the events to ensure reachability to all leaf nodes of the tree and timely completion of all the runs. We identify optimization of execution paths to reduce execution time as our future work.  相似文献   

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