并发约束程序设计语言COPS及其执行模型  

Concurrent Constraint Programming Language COPS and Its Execu tion Model

作　　者：廖乐健 史忠植[2] 曹元大[1] 

机构地区：[1]北京理工大学人工智能研究所,北京100081 [2]中科院计算所智能信息处理开放实验室,北京100080

出　　处：《计算机工程与应用》2003年第14期121-125,共5页Computer Engineering and Applications

基　　金：部委资助项目

摘　　要：约束程序设计尤其是约束逻辑程序设计与并发约束程序设计在AI程序设计领域占据着越来越重要的位置。传统逻辑程序设计的基“计算即为定理证明”的计算风格虽获得了简洁优美的操作语义特性,但也付出了执行效率低的代价,当应用系统规模增大时,其性能严重下降以致崩溃。针对传统逻辑程序设计的这种可伸缩性问题,设计了一个基于并发约束程序设计概念的说明性语言COPS,旨在从语言设计与执行模型两方面降低说明性程序的不确定性,提高搜索与运行效率。在语言设计方面,通过引入确定性语言成分,避免不确定计算用于确定性目标所浪费的系统开销;在执行模型方面,在目标的并发穿叉执行与数据驱动的并发同步机制的基础上,实现“优先执行确定目标”策略与“最少假定”策略,作为约束传播的延伸,最大幅度地剪枝搜索空间,降低搜索复杂性。COPS提供的知识表示、推理与并发机制使其成为构造agent程序的理想语言。论文给出COPS语言的语法规范与执行模型的操作语义描述。Constraint programming especially constraint logic pro gr amming(CLP)and concurrent constraint programming(CCP)is becoming more and more important in the field of AI programming.While the style of pure“comput ation as theorem-proving”in Prolog gains theoretical elegance,it pays the cos t of low execution efficiency.When an application gets large,the system perfor mance falls down or even collapses.Aiming at such scalability problem,the auth ors design a declarative programming language COPS based on the notion of CCP.C OPS reduces program indeterminacy by means of both language design and execution model design.For the language design,determinate language components are intr oduced so as to overcome the inefficiency due to the execution of determinate g oals with indeterminate procedures.For the design of execution model,they exte nd the constraint propagation in CLP to strategies of“determinate goals execut ed first”and“least assumption”in order to maximally prune the search space.C OPS's capabilities of knowledge representation,inference,and concurrency make it a desirable language for agent programming.The paper presents a syntax spec ification and an operational semantic description of the execution model of COPS language.

关 键 词：并发约束程序设计 约束满足 约束逻辑程序设计 

分 类 号：TP311[自动化与计算机技术—计算机软件与理论]