基于时序逻辑的Object-Z类切片的扩展

文中对程序切片进行了研究,报告了程序切片的现状,进行了Object-Z类切片方面的调查.为使(Object-Z规格易于验证,对Obiect-Z作切片处理是必须的.以Ogject-Z的通用堆栈类为实例,对类的描述进行扩展,给出了相应的Kripke结构.通过面向对象程序依赖图对Object-Z进行切片,实现了Object-Z的抽象,给出了对于一个类或具有继承关系的多个类的刻划,即证明了在状态和事件上的公式在原模型与抽象模型中保持,扩展了Object-Z类切片方法.     

基于平台抽象层的进程虚拟机设计与实现

分析WINE虚拟机响应缓慢的根源,提出平台抽象层(PAL)的概念,设计并实现了基于PAL的进程虚拟机Elavm。在Linux, Windows和WinCE上,完成了Elavm PAL的硬件抽象模块、操作系统抽象模块和设备驱动抽象模块。其中,操作系统抽象模块实现了一个通用虚拟内核、一组高效的系统调用和一种基于共享内存的“忙等待”进程间同步方法。测试表明,基于PAL的进程虚拟机,其平均响应时间仅为类WINE虚拟机的千分之一。     

高斯类小波变换的开关电流频域法实现

提出了一种基于频域共享结构的高斯类小波变换的开关电流电路。通过分析在频域具有相似表达的Morlet、Marr和DOG小波函数,基于频域共享单元实现高斯类小波变换频域共享系统。频域共享高斯类小波变换采用开关电流技术实现,不同尺度上的高斯类小波变换可通过调节开关电流电路的时钟频率获得。仿真结果证实了提出方法的有效性。     

对时间自动机进行空性检测的过程和改进

为了提高对时间自动机进行空性检测的效率,研究了使用基于时钟区域(zone)的符号化方法和抽象对时间自动机进行空性检测,提出了针对时间自动机自身特点对检测过程进行改进的方法.通过使用基于zone的符号化表示方法和抽象,一个符号化状态表示显式的状态的集合,时间自动机的状态空间会显著缩小,不同的抽象方法对状态空间有不同的效果.符号化状态间不仅有相等关系还有包含关系,通过判断这种包含关系可以尽早的找到接收路径和避免不必要的状态展开从而提高空性检测的效率.实现了改进的检测过程,对一些例子进行了数据比较,取得了较好的实验结果.     

基于本体的分层抽象模型

KRA表示模型给出了对物理世界W进行形式化建模的一般框架。在扩展后的广义KRA模型中引入本体概念,将抽象对象库扩展为本体类,在本体类中实现KRA模型框架中的感知层、语言层和理论层的知识共享和重用,简化了KRA模型的表示。分别定义了作用在物理世界W和本体类上的3种本体抽象算子(集):基本本体抽象算子、实体本体抽象算子集和连接本体抽象算子集,并给出了本体类之间的映射关系,通过这种映射关系能够实现模型抽象和模型还原。对本体类的抽象度进行形式化的定义,并给出了相关定理,指出在这样的框架中利用抽象映射可以自动构建物理世界W的抽象度不同的模型。     

远程医疗会诊在医学信息共享平台的运用

基于PACS和宽带网的远程医疗信息共享平台是一种能够实现海量存储设备资源共享和不同医院间HIS与HIS、PACS与HIS等异构数据源的连接的信息共享系统。本文介绍基于远程医学信息共享平台的会诊形式创新研究以及实现方法。     

基于QoS的规划选择和构建

当Web服务技术已成为企业间或企业内部系统间,服务发布和共享的首选方式。web服务与Agent结合代表了web服务技术的发展方向之一。服务Agent能够管理一组密切相关的Web服务,并智能化地向外界提供综合的、集成的服务功能。服务Agent内部的规划集合体现了其服务能力。定义了规划的种类、基于目标本体的语义模型和基于ECA规则的语法模型;设计并实现了基于本体推理的目标匹配和基于QoS的规划选择,提出了基于QoS的抽象规划构建;介绍了一个实例和系统实现方法。     

一种基于YOLOv3的共享单车违规停放检测方法

为解决共享单车随意停放给交通管理带来的困难,提出一种基于计算机视觉的共享单车违规停放检测方法。通过多尺度检测训练以及k-means维度聚类改进YOLOv3网络,在此基础上获取共享单车在图片上的特征矩阵,根据特征矩阵计算当前场景下共享单车的运行状态并进行状态统计。在交通监控视频数据集上的测试结果表明,该方法的检测准确率达到87%以上,能够实现共享单车违规停放的有效检测并给出实时预警。     

一种基于Automation的数据共享方法

本文提出了一种基于共享自动化服务器的应用程序间共享数据的方法,该方法利用ActiveX定义的运行对象表(ROT)建立共享服务器,实现客户程序间的数据通讯。本文还讨论了共享服务器对象的生命期问题。     

On using data abstractions for model checking refinements

In this paper we investigate how standard model checkers can be applied to checking refinement relationships between Z specifications. The major obstacle to such a use are the (potentially) infinite data domains in specifications. Consequently, we examine the application of data abstraction techniques for reducing the infinite to a finite state space. Since data abstractions do, however, decrease the amount of information in a specification, refinement can—in general—not be proven on the abstractions anymore, it can only be disproved. The model checker can thus be used to generate counter examples to a refinement relationship. Here, we show how abstract specifications can be systematically constructed (from a given data abstraction) and how a standard model checker (FDR) can be applied to find counter examples in case when refinement is absent. We especially discuss the applicability of the construction method: it constructs abstract specifications which are either upward or downward simulations of the original specifications, and depending on the operations in the specification and the data abstraction chosen, such a construction might succeed or fail. The construction abstracts both the input/output as well as the state.     

面向对象的地物分类法分析与评

摘要:结合南京市区IKONOS高分辨率遥感数据,研究利用面向对象分类法实现地物精确分类的方法和技巧,评估分类结果的精度,探讨面向对象分类法在地物分类应用中的潜力和限制,为高分辨率遥感在地物分类中的有效应用提供新的技术途径。     

基于抽象解释的服务间消息的数据约减

面向服务软件中服务间消息的变量值可能存在无穷域的情况,从而导致模型检测时产生状态空间爆炸问题。为了使终止性验证在实践上可行,需要约减模型状态空间的大小,使得计算时间和空间需求合理。为此,基于抽象解释的区间抽象理论扩展了经典区间抽象域方法,并在统一的区间抽象域方法上借助异常控制流图对变量进行区间分析,在此基础上逆向分析得到服务间消息的变量区间集。变量区间上任意值相对于终止性验证是等价性,因此从每一个变量区间集中选取一个代表值,可组成服务间消息变量的约减值,从而为异常处理的终止性验证提供了约减的初始配置,有效避免了状态空间爆炸。     

Abstract Implementation of Algebraic Specifications in a Temporal Logic Language

A formal technique for incorporating two specification paradigms is presented,in which an algebraic specification is implemented by a set of abstract procedures specified in pre and post-condition style.The link between the two level specifications is provided via a translation from terms of algebraic specifications into temporal logic formulae representing abstract programs.In terms of translation,a criterion for an abstract implementation satisfying its specification is given,which allows one to check the consistency between the two levels of specifications.The abstract implementations can be refined into executable code by refining each abstract procedure in it.It is proved that the satisfication relation between a specification and its implementations is preserved by such refinement steps.     

A unified approach to LMI-based reduced order self-scheduling control synthesis

We consider a reduced order controller synthesis for a general class of control specifications for linear parameter-varying (LPV) systems, when some of state variables are exactly available. The class is defined in an abstract manner so that it uniformly deals with many significant specifications. A necessary and sufficient condition for the existence of a reduced order controller is given in terms of linear matrix inequalities (LMIs). We also show that the order of the controller can be reduced by the number of the state variables exactly available in the measurements. Moreover, in the case of linear time invariant (LTI) systems, a parameterization of all desirable reduced order LTI controllers is given by means of solutions of LMIs. The results in this paper generalize the class of control specifications in which a reduced order controller exists, making it possible to synthesize a reduced order controller based on LMIs for multi-objective control specifications. Furthermore, these results uniformly describe and generalize the existing results on synthesis of a constant state and a full order output feedback controller for LTI and LPV systems such that the specification is given by the existence of a constant positive definite matrix.     

Model transformations across views

Models of software often describe systems by a number of (partially) orthogonal views: a state machine, a class diagram, a scenario might specify different aspects of the one system to be built. Such abstract, multi-view models are the starting point for transformations into platform-specific models and finally the code. However, during these transformations it is usually not possible to keep such a neat separation into different views: the specification language of the target models might not support all such views. The target model, however, still needs to preserve the behaviour of the abstract, multi-view model. Therefore, model transformations have to be capable of moving aspects of the behaviour across views.In this paper, we study model transformations migrating aspects from state-based views (i.e., class specifications with data and methods) to protocol-based views (i.e., process specifications on orderings of methods) and vice versa. The specification languages for these two views are equipped with a joint, formal semantics which enables a proof of behaviour preservation. We consequently derive conditions for our transformations to be behaviour-preserving, where behaviour preservation is characterised by refinement.     

Formal Verification of `Programming to Interfaces'' Programs

This paper presents a formal approach to specify and verify object-oriented programs written in the `programming to interfaces'' paradigm. In this approach, besides the methods to be invoked by its clients, an interface also declares a set of abstract and polymorphic function/predicate symbols, together with a set of constraints about these symbols. The methods declared in this interface are specified using these abstract symbols. A class implementing this interface can give its own definitions to the abstract symbols, as long as all the constraints are satisfied. This class implements all the methods declared in the interface such that the method specification declared in the interface are satisfied w.r.t. the function symbol definitions in this class. Based on the constraints about the abstract symbols, client code using the interfaces can be specified and verified precisely without knowing what classes implement the interfaces. Given more information about the implementing classes, the specifications of the client code can be specialized into more precise ones without re-verifying the client code.     

Synthesizing Distributed Protocol Specifications from a UML State Machine Modeled Service Specification

The object-oriented paradigm is widely applied in designing and implementing communication systems.Unified Modeling Language(UML) is a standard language used to model the design of object-oriented systems.A protocol state machine is a UML adopted diagram that is widely used in designing communication protocols.It has two key attractive advantages over traditional finite state machines:modeling concurrency and modeling nested hierarchical states.In a distributed communication system,each entity of the system has its own protocol that defines when and how the entity exchanges messages with other communicating entities in the system.The order of the exchanged messages must conform to the overall service specifications of the system.In object-oriented systems,both the service and the protocol specifications are modeled in UML protocol state machines.Protocol specification synthesis methods have to be applied to automatically derive the protocol specification from the service specification.Otherwise,a time-consuming process of design,analysis,and error detection and correction has to be applied iteratively until the design of the protocol becomes error-free and consistent with the service specification.Several synthesis methods are proposed in the literature for models other than UML protocol state machines,and therefore,because of the unique features of the protocol state machines,these methods are inapplicable to services modeled in UML protocol state machines.In this paper,we propose a synthesis method that automatically synthesizes the protocol specification of distributed protocol entities from the service specification,given that both types of specifications are modeled in UML protocol state machines.Our method is based on the latest UML version(UML2.3),and it is proven to synthesize protocol specifications that are syntactically and semantically correct.As an example application,the synthesis method is used to derive the protocol specification of the H.323 standard used in Internet calls.