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1.
进程代数可有效地用于Web服务组合的描述和验证,然而缺乏对服务组合成本建模和分析的能力.提出一种扩展了价格信息的进程代数PPA, 在CCS基础上为进程动作和状态扩展价格函数, 给进程动作的执行标记价格,给进程的迁移状态标记成本.给出了PPA的语法和语义,定义了PPA成本弱互模拟并分析了其与CCS弱互模拟的关系,证明了PPA在CCS基础上扩展了成本建模能力,给出了成本状态空间构造算法,该算法支持选择成本优化的组合服务.实验分析了PPA用于Web服务组合成本建模和分析的可行性.  相似文献   

2.
符号迁移图是传值进程的一种直观而简洁的语义表示模型,该模型由Hennessy和Lin首先提出,随后又被Lin推广至带赋值的符号迁移图,本文不但定义了符号迁移图各种版本(基/符号)的强操作语义和强互模拟,提出了相互的强互模拟算法,而且通过引入符号观察图和符号同余图,给出了其弱互模拟等价和观察同余的验证算法,给出并证明了了τ-循环和τ-边消去定理,在应用任何弱互模拟观察同余验证算法之前,均可利用这些定理对所给符号迁移图进行化简。  相似文献   

3.
张阳  张建兵  金文标 《计算机工程与设计》2006,27(9):1560-1562,1565
从计算机集群系统实际应用出发,首先对Java线程的状态进行了分析,介绍了目前Java线程迁移机制的几种实现方法:处理源代码、处理字节码和扩展Java虚拟机的实现机制.从3个不同的方面进行了性能分析和比较,得出一个初步的评估.最后提出了一种扩展Java虚拟机方法的改进以及该迁移技术在集群系统中的应用.  相似文献   

4.
在分析复图像干涉相位对快速互相关算法配准精度影响的基础上,提出了一种快速区域互相关InSAR图像配准方法。该方法对图像的幅度谱进行区域相关操作,获得干涉相位空间角频率的粗估计,并对主图像进行干涉相位补偿。该算法通过上述步骤消除干涉相位变化对算法的影响实现了高精度配准。在仿真实验和实测实验中,通过与传统的快速区域互相关算法及最大频谱法进行对比,验证了本文算法的稳健性与有效性。  相似文献   

5.
王婷  陈铁明  刘杨 《软件学报》2016,27(3):580-592
精化检测是一种重要的形式化验证方法,将系统实现和性质规约用相同形式化语言进行建模,如能证明两者间存在某种精化关系且该关系能够维持性质,可得出系统实现满足性质规约.为验证不同类型的系统性质, traces、stable failures和failures-divergence精化检测方法已被提出.精化检测算法依赖于子集构造,因而其面临状态空间爆炸问题.近年来,已有学者针对NFA语言包含问题提出了基于模拟关系的状态空间消减方法,大大提高了算法性能,且该方法能直接用于traces精化检测.在此基础上,本文提出了基于模拟关系的stable failures和failures-divergence精化检测方法.此外,本文还将精化检测扩展到了时间系统的验证中,提出了基于模拟关系的时间自动机traces精化检测方法.实验结果表明,基于模拟关系的算法效率有很大提高.  相似文献   

6.
孙冬冬  柳青  武旖旎 《计算机科学》2014,41(4):80-85,102
借鉴蚁群算法的思想,提出了一种面向负载均衡的自主式虚拟机动态迁移框架,该框架不需要中央管理模块,能够实现服务器的自主迁移,避免了单点失效。利用智能蚂蚁的搜索,实现了自主式框架的迁移机制,而且使用模糊逻辑推理,根据系统的负载状况自动地调整智能蚂蚁的搜索半径来提高搜索性能。最后扩展了云计算平台CloudSim,实现了提出的虚拟机自主式迁移框架。在扩展后的CloudSim平台上进行的仿真实验验证了该框架的可行性。确定了合适的框架参数,并且通过仿真实验与比较分析,验证了所提出的自主式虚拟机迁移框架具有良好的负载均衡效果。  相似文献   

7.
乔善平  闫宝强 《计算机应用》2016,36(8):2150-2156
针对多标记学习和集成学习在解决蛋白质多亚细胞定位预测问题上应用还不成熟的状况,研究基于集成多标记学习的蛋白质多亚细胞定位预测方法。首先,从多标记学习和集成学习相结合的角度提出了一种三层的集成多标记学习系统框架结构,该框架将学习算法和分类器进行了层次性分类,并把二分类学习、多分类学习、多标记学习和集成学习进行有效整合,形成一个通用型的三层集成多标记学习模型;其次,基于面向对象技术和统一建模语言(UML)对系统模型进行了设计,使系统具备良好的可扩展性,通过扩展手段增强系统的功能和提高系统的性能;最后,使用Java编程技术对模型进行扩展,实现了一个学习系统软件,并成功应用于蛋白质多亚细胞定位预测问题上。通过在革兰氏阳性细菌数据集上进行测试,验证了系统功能的可操作性和较好的预测性能,该系统可以作为解决蛋白质多亚细胞定位预测问题的一个有效工具。  相似文献   

8.
医学图像配准算法中,基于灰度的弹性配准方法具有自动化程度高的优点,但是灰度对应性的模糊容易导致误配准.提出一种利用局部互相关系数作为相似性测度的灰度一致性配准算法.该算法在相似性测度函数中将前向变换和后向变换联系起来,把局部互相关系数的和作为相似性测度函数,并通过在局部互相关系数相似性测度中引入一致性约束条件,有效地确保了前向变换和后向变换的互逆性,同时进一步增强了待配准图像灰度的对应性.  相似文献   

9.
本文提出了一种采用组件技术构架的基于Internet的密码学虚拟实验室的设计模型和实现方法.该虚拟实验室以Java Applet实现客户端,具有Java语言的平台独立性和安全性,以JavaBeans的形式开发组件,提高了系统的开发效率,实现了软件重用,使得系统容易维护和扩充.利用该实验系统,用户能进行可视化的实验流程定制、仿真实验保存,对算法进行验证和性能分析实验,用户还可以加入自己编写的算法进行验证及扩充实验组件,为科研、教学等提供了一个很好的密码学虚拟平台.  相似文献   

10.
提出了一个将手工测试转换为自动测试的轻量级框架。经过扩展Java ME API,Java ME程序(MIDlets)具备拦截和模拟用户输入能力。Java ME测试Agent建立HTTP服务,根据配置文件或Web浏览器控制命令决定工作方式:学习模式或测试模式。在学习方式,Agent根据用户输入生成测试脚本;在测试模式,Agent利用测试脚本模拟测试。在GPS/PDA上实现了测试框架并用实验验证。该解决方案用模拟自动测试代替手工费时费力交互手工测试,提高了测试效率。  相似文献   

11.
Model checking is one of the most commonly used methods for checking program correctness. In this method, one verifies a program model given by the Kripke structure (labeled transition system) rather than the program itself. The specification is usually given as a temporal logic formula. In many subtasks of model checking, it is necessary to use relations that are defined on the set of program models and preserve the satisfiability of temporal logic formulas. There exist many relations of this kind, which are called simulation relations. In the present paper, we introduce a tool designed to check a wide class of simulation relations between finite models of programs. This tool is based on the simulation checking game-theoretic approach. The tool consists of two components. The first component is the formal language, which allows one to define various simulation relations in terms of an antagonistic two-player game. The second component is a software tool that, given two labeled transition systems and simulation definition, is able to check whether this simulation is satisfied between these labeled transition systems.  相似文献   

12.
Modeling arbitrary connectivity changes within mobile ad hoc networks (MANETs) makes application of automated formal verification challenging. We use constrained labeled transition systems as a semantic model to represent mobility. To model check MANET protocols with respect to the underlying topology and connectivity changes, we introduce a branching-time temporal logic. The path quantifiers are parameterized by multi-hop constraints over topologies, to discriminate the paths over which the temporal behavior should be investigated; the paths that violate the multi-hop constraints are not considered. A model checking algorithm is presented to verify MANETs that allow arbitrary mobility, under the assumption of reliable communication. It is applied to analyze a leader election protocol.  相似文献   

13.
一种进化半监督式模糊聚类的入侵检测算法   总被引:3,自引:0,他引:3       下载免费PDF全文
在入侵检测系统中,未知标签数据容易获得,标签数据较难获得,对此提出了一种基于进化半监督式模糊聚类入侵检测算法。算法利用标签数据信息担任染色体的角色,引导非标签数据每个模糊分类的进化过程,能够使用少量的标签数据和大量未知标签数据生成入侵检测系统分类器,可处理模糊类标签,不易陷入局部最优,适合并行结构的实现。实验结果表明,算法有较高的检测率。  相似文献   

14.
It is a known problem that state spaces can grow very big, which makes operating with them (including reducing them) difficult because of memory shortage. In the attempt to extend the size of the state spaces that can be dealt with, we designed and implemented a bisimulation reduction algorithm for distributed memory settings using message passing communication. By using message passing, the same implementation can be used on both large SMP machines and clusters of workstations. The algorithm performs reduction of large labeled transition systems modulo strong bisimulation. We justify its correctness and termination. We provide an evaluation of the worst-case time and message complexity and some performance data from a prototype implementation. Both theory and practice show that the algorithm scales up with the number of workers.  相似文献   

15.
基于一致性测试理论的Statechart描述的测试用例自动生成   总被引:1,自引:0,他引:1  
本文研究Statechart描述的测试语义和测试用例的自动生成.基于Tretmans的从标记转换系统描述自动生成测试用例的方法,我们研究如何从Statechart描述自动生成测试用例.本文的主要贡献在于建立了基于Statechart描述的一致性测试和测试用例生成的形式化基础.为Statechart描述建立了形式化测试语...  相似文献   

16.
Simulation distances are essentially approximations of simulation which provide a measure of the extent by which behaviors in systems are inequivalent. In this paper, we consider the general quantitative model of weighted transition systems, where transitions are labeled with elements of a finite metric space. We study the so-called point-wise and accumulating simulation distances which provide extensions to the well-known Boolean notion of simulation on labeled transition systems.We introduce weighted process algebras for finite and regular behavior and offer sound and (approximate) complete inference systems for the proposed simulation distances. We also settle the algorithmic complexity of computing the simulation distances.  相似文献   

17.
It is a known problem that state spaces can grow very large, which makes operating on them (including reducing them) difficult because of operational memory shortage. In an attempt to extend the size of the state spaces that can be dealt with, we designed and implemented a bisimulation reduction algorithm for distributed memory settings using message passing communication. By using message passing, the same implementation can be used on both clusters of workstations and large shared memory machines. The algorithm performs reduction of large labeled transition systems modulo strong bisimulation. We justify its correctness and termination and provide an evaluation of the worst-case time and message complexity and some performance data from a prototype implementation. Both theory and practice show that the algorithm scales up with the number of workstations.  相似文献   

18.
一种基于矢量方法的等高线自动标定与检验算法   总被引:7,自引:0,他引:7  
王永明 《计算机学报》2002,25(9):976-981
等高线作为传统地图和现代地理信息系统(GIS)的重要要素,常用来表示各种地形变化的形态,基于自动方法的等高线高程标定和检验是地图自动化输入,数字高程模型(DEM)生成的重要手段。该文在基于光栅图像等高级自动标定研究成果的基础上,提出一种新的基于矢量等高线的高程自动标定与检验算法。该算法的核心是生成一种称为包含树的数据结构,然后利用这种数据结构转换成等高线自由树,从而实现对等高线高程的自动标定和检验。  相似文献   

19.
In this paper, we present an algorithm for model-following control of under-actuated systems. To make the algorithm robust, we try to suppress computation errors from approximations which are often encountered in the cases of applying the existing algorithms to the under-actuated systems. In this view, we present an algorithm without any kinds of approximations, even in the cases of under-actuated systems. Finally, we check the examples in which the proposed algorithm is applied to a non-holonomic robot and an aircraft.  相似文献   

20.
One of the best approaches for verifying software systems (especially safety critical systems) is the model checking in which all reachable states are generated from an initial state. All of these states are searched for errors or desirable patterns. However, the drawback for many real and complex systems is the state space explosion in which model checking cannot generate all the possible states. In this situation, designers can use refutation to check refusing a property rather than proving it. In refutation, it is very important to handle the state space for finding errors efficiently. In this paper, we propose an efficient solution to implement refutation in complex systems modeled by graph transformation. Since meta-heuristic algorithms are efficient solutions for searching in the problems with very large state spaces, we use them to find errors (e.g., deadlocks) in systems which cannot be verified through existing model checking approaches due to the state space explosion. To do so, we employ a Particle Swarm Optimization (PSO) algorithm to consider only a subset of states (called population) in each step of the algorithm. To increase the accuracy, we propose a hybrid algorithm using PSO and Gravitational Search Algorithm (GSA). The proposed approach is implemented in GROOVE, a toolset for designing and model checking graph transformation systems. The experiments show improved results in terms of accuracy, speed and memory usage in comparison with other existing approaches.  相似文献   

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