Scheduling speculative work in MUSE and performance results

Work which may later be pruned is called speculative work. In this paper we present and evaluate a simple and efficient strategy, used in the Muse OR-parallel Prolog system, for better scheduling of speculative work. The strategy concentrates workers on the leftmost available work in the Prolog tree as long as there exists enough parallelism, thus emulating the sequential Prolog execution as much as possible. This strategy therefore makes it less probable that unnecessary work is executed. A new cut scheme that reduces the amount of speculative work is also presented. The performance results of our strategy are compared with the performance results of similar strategies implemented in the Aurora OR-parallel Prolog system. The comparison shows that our strategy performs quite well.     

A Prolog simulator for deterministic P systems with active membranes

In this paper we propose a new way to represent P systems with active membranes based on Logic Programming techniques. This representation allows us to express the set of rules and the configuration of the P system in each step of the evolution as literals of an appropriate language of first order logic. We provide a Prolog program to simulate, the evolution of these P systems and present some auxiliary tools to simulate the evolution of a P system with active membranes using 2-division which solves the SAT problem following the techniques presented in Reference.¹⁰ Andrés Cordón-Franco: He is a member of the Department of Computer Science and Artificial Intelligence at the University of Sevilla (Spain). He is also a member of the research group on Natural Computing of the University of Seville. His research interest includes Mathematical Logic, Logic in Computer Science, and Membrane Computing, both from a theoretical and from a practical (software implementation) point of view. Miguel A. Gutiérrez-Naranjo: He is an assistant professor in the Computer Science and Artificial Intelligence Department at University of Sevilla, Spain. He is also a member of the Research Group on Natural Computing of the University of Seville. His research interest includes Machine Learning, Logic Programming and Membrane Computing, both from a theoretical and a practical point of view. Mario J. Pérez-Jiménez, Ph.D.: He is professor of Department of Computer Science and Artificial Intelligence at University of Seville, where he is the head of the Group of Research on Natural Computing, He has published 8 books of Mathematics and Computation, and more than 90 scientific articles in prestigious scientific journals. He is member of European Molecular Computing Consortium. Fernando Sancho-Caparrini: He is a member of the Department of Computer Science and Artificial Intelligence at the University of Sevilla (Spain). He is also a member of the research group on Natural Computing of the University of Seville. His research interest includes Complex Systems, DNA Computing, Logic in Computer Science, and Membrane Computing, both from a theoretical and from a practical point of view.     

OR-parallel execution of Prolog on a multi-sequential machine

Based on extending the sequential execution model of Prolog to include parallel execution, we present a method for OR-parallel execution of Prolog on a multiprocessor system. The method reduces the overhead incurred by parallel processing. It allows many processing elements (PEs) to process simultaneously a common branch of a search tree, and each of these PEs creates its local environment and selects a subtree for processing without communication. The run-time overhead is small: simple and efficient operations for selecting the proper subtree. Communication is necessary only when some PEs have exhausted their search spaces and there are others still searching for solutions. The method is able to utilize most of the technology devised for sequential implementation of Prolog. It is optimized for an architecture that supports broadcast copying.     

String pattern-matching in Prolog

A pattern-matching feature for the Prolog language is described. Through the use of patterns, introduced as Prolog predicates, the feature favors the specification of string handling algorithms in a declarative style. A number of convenient pre-defined patterns, adapted from SNOBOL 4, are included. The use of two-level grammars as a paradigm for developing Prolog programs incorporating the pattern-matching feature is also discussed.     

A wire-wrap design aid,written in Prolog

Wire-wrap based prototypes are widely used to evaluate electronic circuit designs. In the course of evaluation, the design may change, and the prototype must be modified accordingly. Much effort is required both to design an initial prototype implementation, and subsequently to modify an existing prototype to conform to design changes. Some of the problems associated with prototype design and modification are discussed, and the basic aspects of a program which addresses them are presented. An interesting feature of the program is that it uses a novel method, based on optimization by simulated annealing, to minimize wire connection lengths. The entire program is written in Prolog.     

Visual Prolog确定性管理机制剖析

阐明了Visual Prolog中确定性管理机制的目的和方法,归纳了编写确定性和非确定性谓词的基本原则,通过对代码示例中回溯和截断机制的详细分析,给出了结论。     

A~*算法的改进及其PROLOG实现

在人工智能领域中,A~*算法是实现有向图最佳优先搜索的一种启发式算法。本文介绍了A~*算法和对A~*算法的改进——B算法,并叙述了用Turbo Prolog实现B算法的方法。     

实时系统调度算法综述

在多道程序环境下,主存中有多个进程,其数目往往多于处理机数目。操作系统通过处理机调度程序,按照某种调度算法动态地把处理机分配给就绪队列中的一个进程,使之执行。处理机是重要的计算机资源,提高处理机的利用率及改善系统性能（吞吐量、响应时间）,很大程度上取决于处理机调度性能的好坏,因而操作系统的调度算法是非常重要的。通过研究基本的操作系统作业（进程）调度算法,详尽分析和对比这些调度算法的优势和劣势。最后对新兴的实时系统研究现状进行介绍和展望,为以后实时系统调度算法研究提供了有效的参考价值。     

基于Prolog的专家系统研究与应用

随着计算机与网络通信技术的迅猛发展,特别是互联网的大规模普及,围绕人工智能与专家系统的研究和应用开发也迎来一个蓬勃发展的新时期。Prolog语言是人工智能与专家系统领域最著名的逻辑程序设计语言。本文基于Prolog平台上,探讨了专家系统建造的原理和应用。     

基于Prolog的专家系统研究与应用

随着计算机与网络通信技术的迅猛发展,特别是互联网的大规模普及,围绕人工智能与专家系统的研究和应用开发也迎来一个蓬勃发展的新时期。Prolog语言是人工智能与专家系统领域最著名的逻辑程序设计语言。本文基于Prolog平台上,探讨了专家系统建造的原理和应用。     

Scheduling Video Streams in Video-on-Demand Systems: A Survey

Developments in multimedia technology over the past decade has caused video-on-demand services to emerge as a new paradigm in home entertainment. Because of the large volume of data involved in the process and stringent continuity and real-time constraints, these services pose challenges that are different from the standard file transfer operations in the network. The necessity of efficient usage of scarce resources like network bandwidth and server capacity (in terms of I/O bandwidth) demands novel and easy-to-use schemes for scheduling continuous video streams. This paper presents an overview of the major scheduling policies that have emerged in the recent past. In particular, the paper provides detailed discussion on policies based on principles of broadcasting, batching, caching, and piggybacking or merging. Policies like look-ahead scheduling schemes that are designed exclusively to provide certain interactive VCR-like control operations are also covered. A conceptual comparison between the various classes of scheduling policies is carried out to identify common threads and key concepts. Performance of these policies in terms of bandwidth demand reduction, customer waiting time reduction, provision of interactive control by the user, and fairness of service are given special emphasis. The paper concludes with a discussion on the possible avenues of further reasearch and development in this potentially interesting and challenging field.     

面向MES的炼钢-连铸协同调度系统

针对某大型钢铁联合企业炼钢．连铸主辅设备协同调度的难题,采用基于“数据、模型、知识、人机交互”四维一体的调度方法,提出了冶金MES中炼钢．连铸协同调度系统的设计原则,系统结构和功能。研发了炼钢．连铸生产调度、钢包优化配备、行车和台车协同调度系统。实际数据模拟效果良好,验证了炼钢．连铸协同调度系统的结构和方法的可行性,并受到现场调度专家的好评。     

一个动态自适应任务调度机制

提出了一个动态的集中式自适应任务调度策略,充分考虑到负载均衡的同时,尽量减少集中调度主机的负担.实验数据证明该任务调度机制能获得良好的效果.     

二阶谓词在人工智能实验平台PIE中的实现

在分析PIE二阶谓词和内部执行流程的基础上,阐述在PIE中实现二阶谓词的方法和技术。     

Path Analysis and Renaming for Predicated Instruction Scheduling

Increases in instruction level parallelism are needed to exploit the potential parallelism available in future wide issue architectures. Predicated execution is an architectural mechanism that increases instruction level parallelism by removing branches and allowing simultaneous execution of multiple paths of control, only committing instructions from the correct path. In order for the compiler to expose and use such parallelism, traditional compiler data-flow and path analysis needs to be extended to predicated code. In this paper, we motivate the need for renaming and for predicates that reflect path information. We present Predicated Static Single Assignment (PSSA) which uses renaming and introduces Full -Path Predicates to remove false dependences and enable aggressive predicated optimization and instruction scheduling. We demonstrate the usefulness of PSSA for Predicated Speculation and Control Height Reduction. These two predicated code optimizations used during instruction scheduling reduce the dependence length of the critical paths through a predicated region. Our results show that using PSSA to enable speculation and control height reduction reduces execution time from 12 to 68%.     

并行自动测试系统的任务调度

并行测试技术的广泛应用,将是下一代自动测试系统(AutomaticTestSystem,ATS)的主要特征。通过对现有并行技术的分析,介绍了目前实现并行测试的主要方法,并根据任务量的多少提出了,相应的任务调度算法,通过实验证明算法是可行的。     

可任意划分负载的调度模型、算法与应用

随着数据并行应用需求的日益增长,可任意划分负载的调度问题已经成为并行调度领域新的研究热点.回顾了可任意划分负载调度的基本模型及近年来对这个基本模型的扩展性研究,并给出了它的应用研究和今后的发展方向.     

Kernel Prolog 数据库访问扩展及B/S结构改造

研究了基于Kemel Prolog的解释器原型,扩展了Kemel Prolog,使之能够连接Microsoft SQL Server数据库并进行相应的数据库操作,将Kernel Prolog单机版改造成为B／S结构运行的版本,并使两个版本可以同时运行和修改,使Prolog解释／编译器具备数据库访问功能,对推广Prolog应用很有意义。