适用于并行操作的C语言程序式工具ParCT

并行计算技术的飞速发展给软件测带来了新的要求，并行软件测试可以分为基于进程内部的控制流测试和基于进程间相互关系的时序测试。文中所介绍的并行软件的测试工具－ＰａｒＣＴ主要是面向控制流的。     

多线程技术在工作记忆测试程序中的应用

研究人脑的工作记忆系统的测试程序涉及到两个同时执行的并行动作。为了保证测试结果的精度和有效性,测试程序采用多线程技术实现了在工作记忆测试过程中显示字符序列和记录被测试者的反应时间这两个动作的并行执行。测试程序在主线程记录测试者的反应时间,而在另外一个线程中显示测试序列,两个线程的并行执行保证了测试结果的精度。     

多线程技术在工作记忆测试程序中的应用

研究人脑的工作记忆系统的测试程序涉及到两个同时执行的并行动作.为了保证测试结果的精度和有效性.测试程序采用多线程技术实现了在工作记忆测试过程中显示字符序列和记录被测试者的反应时间这两个动作的并行执行.测试程序在主线程记录测试者的反应时间,而在另外一个线程中显示测试序列,两个线程的并行执行保证了测试结果的精度.     

Concurrent Manipulation of Expanded AVL Trees

The concurrent manipulation of an expanded AVL tree(EAVL tree)s considered in this paper.The presented system can support any number of concurrent processes which perform searching,insertion and deletion on the tree.Simulation results indicate the high performance of the system.Elaborate techniques are used to achieve such a system unavailable based on any known algorithms.Methods developed in this paper may provide new insights into other problems in the area of concurrent search structure manipulation.     

ORCA：实现与应用

Ａｍｏｅｂａ是荷兰学者Ｖｒｉｊｅ Ｕｎｉｖｅｒｓｉｔｉｅｔ开发的分布式操作系统，而ＯＲＣＡ是为分布式用户而设计的一种新的程序设计语言。ＯＲＣＡ建立在共享数据目标模型的基础上，它必须给出共享地址空间语义，并不要求实际的物理共享存储器。论文概述了ＯＲＣＡ实现和使用方面的经验。     

一种框架时序逻辑程序设计语言

本文提出了区间时序逻辑的一个变种——投影时序逻辑，给出了它的语法规则和语义定义，并建立了该逻辑系统的模型理论。在该逻辑系统中，我们引入了一个新的投影操作符(prj)。这使得我们不仅能够在不同的时间层次上控制进程的并行操作，而且可以以该操作符为基础定义顺序操作符(chop)和并行操作符(‖)。因此，该逻辑系统比区间时序逻辑具有更强的表达能力。同时，本文也给出了与投影操作相关的一些性质。     

Java操作系统

Java是网络上的通用程序设计语言,它是一种跨平台的、适合于网络计算环境的面向对象语言.Java操作系统(JavaOS)是一个优化运行的Java新平台.JavaOS使Java应用程序直接运行在硬件平台上,而不需要宿主操作系统.这些Java应用程序是高交互性的、动态、安全的.目前存在许多平台,如Windows、Macintosh、OS/2、Unix、Solaris和Netware,软件必须编译、测试、打包,分别运行在每     

Cova: A programming language for cooperative applications

This paper discusses Cova, a novel programming language designed to develop integra-tive cooperative applications and the issues related to the design and implementation of its runtime system.     

全复制结构下基于对象数据模型的并发控制

以全复制结构实现的同步群件系统中一个重要问题就是寻求一种能够支持人机及用户间自然、自由交互的并发控制方法,文中首先总结了以往的研究在这个问题上所取得的结果,并分析了这些结果不的不足,然后基于一种扩展的ＯＤＭＧ对象模型给出了一种全新的并发控制模型ｏｏｄＯＰＴ,该模型的主要思想是利用对象本身及其上所定义的操作的语义进行冲突解析,文中分析了不同语义对象上操作之间的冲突情况并给出了解析这些冲突的方法,以此     

一种新的实时数据库的乐观并发控制协议

针对一些并发控制协议中由于过多的事务重启动造成资源浪费,提出了一种新的乐观并发控制协议(Optimistic Concurrency Control),通过向后调整不严重冲突事务的动态串行化顺序,许多不必要的事务重启动可以避免。在一个事务的读阶段不用记录事务冲突和串行化限制,各种优先级冲突解决方法可以很方便地加入到该协议中,根据需要选择使用了优先级-中止-50机制。     

Prescheduling policy for real-time concurrency control: A performance evaluation

A new priority management policy, aprescheduling policy, is proposed. This policy can be applied on any conventional concurrency control protocol to schedule a real-time transaction. Costly preemption is avoided by the prescheduling policy, and parsing dataset of a transaction is not needed. Three widely used conventional concurrency control protocols (dynamic two-phase locking, basic timestamp ordering, and optimistic) are incorporated with the prescheduling policy to form three real-time concurrency control protocols. Performance of the three protocols is evaluated from three different viewpoints: database management systems, protocols, and transaction. From a database management system viewpoint, we show the prescheduling policy can improve the performance of protocols by raising thevalid ratio and reducingrestart counts. In general, two-phase locking with the prescheduling policy performs the best in most cases and yields the best choice for concurrency control in a real-time application. Deciding factors that affect performance of each protocol are identified from protocol viewpoint. Some suggestions are given for writing a timely transaction from the aspect of transaction viewpoint.     

A framework for awareness maintenance

This paper presents a systematic literature review to gain insight into the growing area of awareness maintenance. A systematic review of papers from 1970 to 2010 examines the background and trends of research in this area. The results establish a framework for awareness maintenance and demonstrate trends, gaps, and potentially fruitful areas for future research. In particular, based on 131 papers, the present work proposes a four-phase framework for awareness maintenance that shows promise for real-world applications.     

Gria: an efficient deterministic concurrency control protocol

Deterministic databases are able to reduce coordination costs in a replication. This property has fostered a significant interest in the design of efficient deterministic concurrency control protocols. However, the state-of-the-art deterministic concurrency control protocol Aria has three issues. First, it is impractical to configure a suitable batch size when the read-write set is unknown. Second, Aria running in low-concurrency scenarios, e.g., a single-thread scenario, suffers from the same conflicts as running in high-concurrency scenarios. Third, the single-version schema brings write-after-write conflicts. To address these issues, we propose Gria, an efficient deterministic concurrency control protocol. Gria has the following properties. First, the batch size of Gria is auto-scaling. Second, Gria’s conflict probability in low-concurrency scenarios is lower than that in high-concurrency scenarios. Third, Gria has no write-after-write conflicts by adopting a multi-version structure. To further reduce conflicts, we propose two optimizations: a reordering mechanism as well as a rechecking strategy. The evaluation result on two popular benchmarks shows that Gria outperforms Aria by 13x.     

Multiversion concurrency control for the generalized search tree

Many read‐intensive systems where fast access to data is more important than the rate at which data can change make use of multidimensional index structures, like the generalized search tree (GiST). Although in these systems the indexed data are rarely updated and read access is highly concurrent, the existing concurrency control mechanisms for multidimensional index structures are based on locking techniques, which cause significant overhead. In this article we present the multiversion‐GiST (MVGiST), an in‐memory mechanism that extends the GiST with multiversion concurrency control. The MVGiST enables lock‐free read access and ensures a consistent view of the index structure throughout a reader's series of queries, by creating lightweight, read‐only versions of the GiST that share unchanging nodes among themselves. An example of a system with high read to write ratio, where providing wait‐free queries is of utmost importance, is a large‐scale directory that indexes web services according to their input and output parameters. A performance evaluation shows that for low update rates, the MVGiST significantly improves scalability w.r.t. the number of concurrent read accesses when compared with a traditional, locking‐based concurrency control mechanism. We propose a technique to control memory consumption and confirm through our evaluation that the MVGiST efficiently manages memory. Copyright © 2009 John Wiley & Sons, Ltd.     

Advanced concurrency control in Java

Developing concurrent applications is not a trivial task. As programs grow larger and become more complex, advanced concurrency control mechanisms are needed to ensure that application consistency is not compromised. Managing mutual exclusion on a per‐object basis is not sufficient to guarantee isolation of sets of semantically‐related actions. In this paper, we consider ‘atomic blocks’, a simple and lightweight concurrency control paradigm that enables arbitrary blocks of code to access multiple shared objects in isolation. We evaluate various strategies for implementing atomic blocks in Java, in such a way that concurrency control is transparent to the programmer, isolation is preserved, and concurrency is maximized. We discuss these concurrency control strategies and evaluate them in terms of complexity and performance. Copyright © 2002 John Wiley & Sons, Ltd.     

一种面向多租户中间件的应用级并发控制方法

针对在多租户中间件上存在的租户隔离、资源侵占的问题,提出一种面向多租户中间件的应用级并发控制方法。首先分析了现有并发控制方法的局限性,然后介绍了一种基于工作管理器的多租户请求处理模型的原理及设计,进一步给出了基于该模型的应用级并发控制方法的设计与实现,最后通过实验测试方法的性能开销,并设计了一个多租户性能隔离方法来验证方法的应用效果。实验结果验证了方法的有效性。     

Software development and integration in a computer supported cooperative work environment

This paper presents a prototype computer supported cooperative work (CSCW) environment that supports the engineering design process. In particular, this environment provides collaborative tools that support computer-aided design (CAD) and computer-aided software engineering (CASE). This paper takes an high level look at the system as a whole and then focuses on the method used to implement the CASE support. It addresses how group members can simultaneously work on coding a program and then integrate their work to form a single program inside this environment. © 1998 John Wiley & Sons, Ltd.