一种语义感知的安全检查检测方法

安全检查是OS中最常见的安全增强方式,是漏洞检测的重要基石。检测安全检查必然要用到异常处理函数,本论文从检测异常处理函数入手,实现了基于异常处理函数的安全检查检测方法。论文提出了一种语义感知的安全检查检测方法（Sased）,通过基于自然语义、程序语义的异常处理函数检测方法对Linux系统的函数控制流进行静态分析。同时,Sased可以对异常处理函数和安全检查进行回溯过滤从而降低其误报率。通过实验,Sased共报告异常处理函数795个,安全检查41519个,二者都达到了90%以上的检测准确率。这其中,有208个异常处理函数是之前的工作中从未发现的。同时,我们结合已有的漏洞检测方法,发现了Linux内核的9个新漏洞。实验表明Sased可以非常高效地检测OS中的异常处理函数及安全检查,从而为操作系统漏洞检测提供有益的参考。     

Robust data types

Summary Data types with total operations and exceptions are proposed as basic building blocks for the construction of modular robust software. A notation for specifying such data types is presented and the issues underlying their correct implementation in a programming language supporting data abstraction and exception handling are discussed and illustrated by examples. New light is shed on some important aspects of exception handling such as the identification and specification of exceptions, the precise detection of exception occurrences, recovery of consistent states after exception detections and verification of the correct implementation of specified exceptional effects for operations.     

A Simple and Systematic Approach to Assigning Denavit–Hartenberg Parameters

This paper presents a simple and intuitive approach to determining the kinematic parameters of a serial-link robot in Denavit-Hartenberg (DH) notation. Once a manipulator's kinematics is parameterized in this form, a large body of standard algorithms and code implementations for kinematics, dynamics, motion planning, and simulation are available. The proposed method has two parts. The first is the ldquowalk through,rdquo a simple procedure that creates a string of elementary translations and rotations, from the user-defined base coordinate to the end-effector. The second step is an algebraic procedure to manipulate this string into a form that can be factorized as link transforms, which can be represented in standard or modified DH notation. The method allows for an arbitrary base and end-effector coordinate system as well as an arbitrary zero joint angle pose. The algebraic procedure is amenable to computer algebra manipulation and a Java program is available as supplementary downloadable material.     

基于程序分析的代码查询技术

策略描述语言是策略驱动的面向服务流程异常处理方法的基础和前提。针对目前已有策略语言在描述面向服务流程异常处理逻辑方面的不足,提出了一种新的面向服务流程异常处理的策略描述语言WS-Policy4BPEH。它在Web服务策略框架的基础上,扩展了ECA对规则执行影响的描述,定义了多种面向服务流程的异常处理动作模式,能够详细、准确地描述异常及异常处理方式、返回方式和传播方式。WS-Policy4BPEH采用XML作为元语言,因此具有良好的可扩展性。     

Foundations of the trace assertion method of module interfacespecification

The trace assertion method is a formal state machine based method for specifying module interfaces. A module interface specification treats the module as a black-box, identifying all the module's access programs (i.e., programs that can be invoked from outside of the module) and describing their externally visible effects. In the method, both the module states and the behaviors observed are fully described by traces built from access program invocations and their visible effects. A formal model for the trace assertion method is proposed. The concept of step-traces is introduced and applied. The stepwise refinement of trace assertion specifications is considered. The role of nondeterminism, normal and exceptional behavior, value functions, and multiobject modules are discussed. The relationship with algebraic specifications is analyzed. A tabular notation for writing trace specifications to ensure readability is adapted     

一种IMS网络信令异常处理检测方法

针对IMS网络中被入侵或劫持的网络实体可能对信令消息做出恶意篡改等异常处理的问题,提出一种基于信令处理规则的IMS 网络信令异常处理检测方法.该方法基于建立的信令处理规则库,模拟实体对信令消息的正常处理并生成一条预处理消息,通过判断预处理消息与经过实体处理后的信令消息是否匹配,检测IMS网络中是否存在信令异常处理.实验结果表明,该方法对信令异常处理的检测率达到了100％.     

Approximation of algebraic and trigonometric polynomials by feedforward neural networks

This paper presents a function approximation to a general class of polynomials by using one-hidden-layer feedforward neural networks(FNNs). Both the approximations of algebraic polynomial and trigonometric polynomial functions are discussed in details. For algebraic polynomial functions, an one-hidden-layer FNN with chosen number of hidden-layer nodes and corresponding weights is established by a constructive method to approximate the polynomials to a remarkable high degree of accuracy. For trigonometric functions, an upper bound of approximation is therefore derived by the constructive FNNs. In addition, algorithmic examples are also included to confirm the accuracy performance of the constructive FNNs method. The results show that it improves efficiently the approximations of both algebraic polynomials and trigonometric polynomials. Consequently, the work is really of both theoretical and practical significance in constructing a one-hidden-layer FNNs for approximating the class of polynomials. The work also paves potentially the way for extending the neural networks to approximate a general class of complicated functions both in theory and practice.     

基于异常检测和处理的动态适应性工作流

异常的检测和处理是工作流系统执行过程中必须解决的关键性问题之一.给出了异常的分类,并给出了异常自身及其处理方法的形式化描述;实现了利用消息传递机制作为异常的检测方法,并结合异常适应库来提供异常处理的执行策略和处理措施;通过为相应的措施设计特定的操作原语,从而为其转变为实际的编码提供了可能.     

Algebraic and operational semantics of specifications allowing exceptions and errors

The specification of abstract data types requires the possibility to treat exceptions and errors. We present an approach allowing all forms of error handling: error introduction, error propagation and error recovery. The algebraic semantics of our method and a new correctness criterion are given. We also introduce an operational semantics of a subclass of our specifications which coincides with the algebraic semantics.     

Reverse polish notation method

The reverse Polish notation (RPN) is a well-known method for the expression notification in a postfix manner, instead of using the usual infix notation. Authors made a method for symbolic computation based on RPN. This method is successfully applied on a number of problems. In this article, there is a brief survey of these applications. In addition, the application of the method on algebraic computation of unary pairfunctions is presented.     

A rule-based approach to proactive exception handling in business processes

Effectively handling exceptions in business process is an important capability of enterprises in the current global market environment, since their business processes are becoming more complex. Effective exception handling requires systematic support for the entire scope of exception handling: from exception prediction to exception prevention, and from exception detection to exception resolution. Most existing research approaches to exception handling in business process management and workflow areas have focused on reactive exception handling which resolves exceptions only after their occurrences. Therefore, a proactive exception handling approach is required to predict and prevent business process exceptions as early as possible before they occur, and detect and resolve exceptions as soon as possible after they occur. This paper presents comprehensive behavioral, functional, and informational requirements for proactive exception handling from the lifecycle perspective. Then, it proposes a rule language for proactive exception handling based on the requirements. The proposed rule language will enable effective and flexible exception handling by providing the information required for the entire scope of exception handling, especially, for exception prediction and prevention. Finally, the paper illustrates and validates the rule language with an example of exception prevention and a prototype system.     

迁移工作流系统中的工作位置异常处理模型

针对迁移工作流异常的本地特性和工作位置的体系结构,提出一种基于事件-条件-动作(ECA)规则和案例推理(CBR)的工作位置异常处理模型。该模型采取主动检测和异常检测混合的检测技术,利用本地异常规则库实现工作位置异常处理。应用结果表明,该模型增强了不可预测异常、可预测异常的处理能力。     

基于SPARC的VxWorks异常处理研究

本文详细阐述了VxWorks for SPARC的异常处理机制,分析VxWorks操作系统对于异常处理的流程,指出其中不适应于高可靠性嵌入式应用的地方,并提出了结合当前应用设计异常处理策略的改进优化方案,结合SPARC体系架构的TSC695F处理器,完成了异常处理改进方法并通过实验验证。实验结果表明,改进的异常处理方案大大提高了VxWorks运行的可靠性,本文的研究成果已应用于国家某重大项目。     

Compositional semantics of a real-time prototyping language

The formal semantics of a prototyping language for hard real-time systems, PSDL, is given. PSDL provides a data flow notation augmented by application-orientation timing and control constraints to describe a system as a hierarchy of networks of processing units communicating via data streams. The semantics of PSDL are defined in terms of algebraic high-level Petri nets. This formalism combines algebraic specifications of abstract data types with process and concurrency concepts of Petri nets. Its data abstraction facilities are used to define the meaning of PSDL data types, while high-level Petri nets serve to model the casual and timing behavior of a system. The net model exposes potential concurrency of computation and makes all synchronization needs implied by timing and control constraints explicit and precise. Time is treated as state of clocks, and clocks are modeled as ordinary system components. The net semantics provides the basis for applying analysis techniques and semantic tools available for high-level Petri nets     

浮点数学函数异常处理方法

异常会造成程序错误,实现完全没有异常的浮点计算软件也很艰难,因此,实现有效的异常处理方法很重要.但现有的异常处理并不针对浮点运算,并且研究重点都集中在整数溢出错误上,而浮点类型运算降低了整数溢出存在的可能.针对上述现象,面向基于汇编实现的数学函数,提出了一种针对浮点运算的分段式异常处理方法.通过将异常类型映射为64位浮点数,以核心运算为中心,将异常处理过程分为3个阶段:输入参数检测(处理INV异常)、特定代码检测(处理DZE异常和INF异常)以及输出结果检测(处理FPF异常和DNO异常),并从数学运算的角度对该方法采用分段式处理的原因进行了证明.实验将该方法应用于Mlib浮点函数库,对库中600多个面向不同平台的浮点函数进行了测试.测试结果表明:该方法能够将出现浮点异常即中断的函数个数从90%降到0%.同时,实验结果验证了该方法的高效性.