Algebraic processing technique for extracting frequency-dependent shear-wave splitting parameters in an anisotropic medium

Based on the dual source cumulative rotation technique in the time-domain proposed by Zeng and MacBeth（1993）,a new algebraic processing technique for extracting shear-wave splitting parameters from multi-component VSP data in frequency-dependent medium has been developed.By using this dual source cumulative rotation technique in the frequency-domain（DCTF）,anisotropic parameters,including polarization direction of the shear-waves and timedelay between the fast and slow shear-waves,can be estimated for each frequency component in the frequency domain.It avoids the possible error which comes from using a narrow-band filter in the current commonly used method.By using synthetic seismograms,the feasibility and validity of the technique was tested and a comparison with the currently used method was also given.The results demonstrate that the shear-wave splitting parameters frequency dependence can be extracted directly from four-component seismic data using the DCTF.In the presence of larger scale fractures,substantial frequency dependence would be found in the seismic frequency range,which implies that dispersion would occur at seismic frequencies.Our study shows that shear-wave anisotropy decreases as frequency increases.

Research Progress of the Algebraic and Geometric Signal Processing

The investigation of novel signal processing tools is one of the hottest research topics in modern signal processing community. Among them, the algebraic and geometric signal processing methods are the most powerful tools for the representation of the classical signal processing method. In this paper, we provide an overview of recent contributions to the algebraic and geometric signal processing. Specifically, the paper focuses on the mathematical structures behind the signal processing by emphasizing the algebraic and geometric structure of signal processing. The two major topics are discussed. First, the classical signal processing concepts are related to the algebraic structures, and the recent results associated with the algebraic signal processing theory are introduced. Second, the recent progress of the geometric signal and information processing representations associated with the geometric structure are discussed. From these discussions, it is concluded that the research on the algebraic and geometric structure of signal processing can help the researchers to understand the signal processing tools deeply, and also help us to find novel signal processing methods in signal processing community. Its practical applications are expected to grow significantly in years to come, given that the algebraic and geometric structure of signal processing offer many advantages over the traditional signal processing.

Model for Software Behaviour Detection Based on Process Algebra and System Call

Behaviour detection models based on automata have been studied widely. By add- ing edge ε, the local automata are combined into global automata to describe and detect soft- ware behaviour. However, these methods in- troduce nondeterminacy, leading to models that are imprecise or inefficient. We present a model of software Behaviour Detection based on Process Algebra and system call （BDPA）. In this model, a system call is mapped into an action, and a function is mapped into a process We construct a process expression for each function to describe its behaviour. Without con- strutting automata or introducing nondeter- minacy, we use algebraic properties and algo- rithms to obtain a global process expression by combining the process expressions derived from each function. Behaviour detection rules and methods based on BDPA are determined by equivalence theory. Experiments demon- strate that the BDPA model has better preci- sion and efficiency than traditional methods.

Modeling and Analysis for Supply Chain Using Stochastic Process Algebra

In order to improve the influence of the uncertain and dynamic of node enterprise behavior on the performance of supply chain,the method based on stochastic process algebra for description,analysis,validation and evaluation of supply chain business process model is proposed.Firstly,the description of the uncertainty of node enterprise behavior is given using the extended Unified Modeling Language sequence diagram,and mapping rule is defined from the extended Unified Modeling Language sequence diagram to stochastic process algebra.Secondly,on the basis of the acquired stochastic process algebra model,the supply chain business process model is verified with Mobility Workbench.Finally,according to the operational semantics of stochastic process algebra,the continuous-time Markov chain,isomorphic with stochastic process algebra model,is built; and the system performance evaluation of transient status and stable status is respectively conducted in accordance with Markov transfer relations and the current state of system,obtaining the predicted performance value and average performance index value for a specific period of time.The simulation experiments show that the proposed method can accurately describe the stochastic behaviors of supply chain system and interactions among nodes,effectively verify the validity of the model,and objectively and exactly evaluate design of the supply chain.

Research on Production Process Control Method Combined Stochastic Process Algebra and Stochastic Petri Nets

A hierarchical closed-loop production control scheme integrating scheduling,control and performance evaluation is discussed.Firstly,the production process is divided into two main hierarchies:the lower level is the physical operation level and the upper one is the management level.Secondly,the schedule template for the management level and the activity template for the physical operation level are constructed separately,the tasks in the schedule have the ability to make partial decisions,and the per- formance parameters are introduced into activity template.Thirdly,the two levels use different model representations:stochastic process algebra for the management level whose output is the control commands and stochastic Petri net for the physical operation lev- el which is the execution of the control commands.Then,the integration of the two levels is the control commands mapping into the lower physical operations and the responses feeding back to the upper decision-making that are defined by some transition functions. Under the proposed scheme,the production process control of a flexible assembly is exemplified.It is concluded that the process con- trol model has partial ability to make decision on-line for uncertain and dynamic environments and facilitates reasoning about the be- haviors of the process control,and performance evaluation can be done online for real-time scheduling to ensure the global optimiza- tion.

Verification of Hypertorus Communication Grids by Infinite Petri Nets and Process Algebra

A model of a hypertorus communication grid has been constructed in the form of an infinite Petri net. A grid cell represents either a packet switching device or a bioplast cell. A parametric expression is obtained to allow a finite specification of an infinite Petri net. To prove properties of an ideal communication protocol, we derive an infinite Diophantine system of equations from it, which is subsequently solved. Then we present the programs htgen and ht-mcrl2-gen, developed in the C language, which generate Petri net and process algebra models of a hypertorus with a given number of dimensions and grid size. These are the inputs for the respective modeling tools Tina and mCRL2, which provide model visualization, step simulation, state space generation and reduction, and structural analysis techniques. Benchmarks to compare the two approaches are obtained. An ad-hoc induction-like technique on invariants,obtained for a series of generated models, allows the calculation of a solution of the Diophantine system in a parametric form.It is proven that the basic solutions of the infinite system have been found and that the infinite Petri net is bounded and conservative. Some remarks regarding liveness and liveness enforcing techniques are also presented.

农林院校线性代数课程小班授课模式改革与研究

线性代数是农林院校中一门重要的数学基础课,但目前由于多种因素的限制,该课程大多采用大班授课模式进行教学,教学效果难以提高。针对线性代数课程大班授课模式下存在的多种问题,进行了小班授课模式的改革和研究。在教学方式上灵活采用翻转课堂、课堂讨论、竞答比赛、引导总结等多种教学形式,课程考核增加过程评价;在教学过程中融入专业应用知识,实现“通专融合”;结合网络课程平台与智慧化教学手段,加强信息化教育。实践表明,线性代数课程的小班授课模式有利于提高学生的学习状态和综合能力,推进线性代数教学改革,也是学校培养卓越农林人才教学模式的有效探索与实践。另外,基于线性代数课程的小班授课模式也为其他通识课程的教学提供参考和选择。

Computation Method for the Real-Time Control Problems in Differential-Algebraic Systems

In this paper, a real-time computation method for the control problems in differential-algebraic systems is presented. The errors of the method are estimated, and the relation between the sampling stepsize and the controlled errors is analyzed. The stability analysis is done for a model problem, and the stability region is ploted which gives the range of the sampling stepsizes with which the stability of control process is guaranteed.

基于矩阵乘法关联的分级图像秘密共享方案

针对目前图像秘密共享中缺乏集合内或集合间多级权限控制的细粒度问题,提出一种基于矩阵乘法构造分级恢复的图像秘密共享方案。利用图像所具有的矩阵属性,在对原始像素干扰最小的情况下,通过矩阵可逆乘法构建秘密图像之间的关联矩阵,引入效率较高的矩阵运算进行共享份额生成与秘密恢复。当参与者集合中必要参与者满足对应门限时,可恢复第一级秘密图像;当全体参与者满足整体门限时,可恢复第二级秘密图像。仿真结果表明,该加密算法具有良好的安全性与鲁棒性。

一种软件演化过程模型的代数语义

随着大量的软件演化过程模型被软件演化过程元模型建模产生,如何验证过程模型的正确性,是摆在人们面前的一个重要任务.针对软件演化过程元模型,引入进程代数ACP(algebra of communicating processes)对其扩展,提出软件演化过程元模型代数,使用进程项指定软件演化过程模型的代数语义,在进程代数的统一框架下,基于等式推理验证软件演化过程模型的行为,使行为验证方式从模型推导变为代数推导.这种方法充分结合了Petri网和ACP的长处,可以有效地支持软件演化过程的形式验证.

改进的基于过程代数的BPR方法及应用研究

针对基于过程代数的BPR方法在描述和分析复杂业务流程时存在的不足,提出了改进的基于过程代数的BPR方法,并应用该方法描述和分析传统物流配送业务流程,同时结合BPR原则和电子商务环境下物流配送的特点对传统物流配送业务流程进行重组,从而构建了适应电子商务环境的物流配送业务流程。最后,通过对流程重组前后评价指标的计算,取得了令人满意的结果。

面向服务的可信软件体系结构代数模型

针对面向服务体系结构(Service Oriented Architecture,SOA)在形式化和可信属性建模方面的不足,用代数学方法对服务、服务组合以及服务体系结构的属性和行为特征进行抽象,把服务组合解释成组件"运算"实现,并结合进程代数中算子概念,定义了多种服务组合运算,从而建立SOA的代数模型.在代数模型基础上,进一步对SOA可信属性建模,提出多种SOA可信范式,为可信SOA软件设计提供理论支持.最后介绍了一个应用案例.

基于过程代数的电子商务定价业务流程的重组与优化

针对传统定价业务流程中存在的信息化、自动化程度不高以及网络化水平低下等不合理因素,采用基于过程代数的业务流程定量分析方法对传统定价业务流程中的各个步骤进行分析,结合业务流程重组的原则和电子商务环境下定价业务流程的特点,对传统定价业务流程进行重组,构建电子商务环境下的定价业务流程,并对重组前后的结果进行评价.结果表明,重组后的定价业务流程,能减少工作量和工作失误,加强定价系统对电子商务企业的快速响应能力.

基于过程代数的可变业务流程建模方法

为实现灵活的业务流程重组,提出了一种面向流程变化调整的业务流程模型。该模型从业务逻辑中抽取出流程相关性语义,用连接器的模式来实现一种可配置的流程属性。业务人员可以通过调整模型中的连接器对流程进行重新配置,从而实现业务流程重组的软件调整。给出了模型的过程代数描述,并介绍了建模步骤和流程调整方法。最后,以机场塔台调度流程的建模和调整过程为例,对相关问题进行了讨论。

基于FPGA和DSP实现的实时图像压缩

利用FPGA的并行分布流水特点 ,选用exilinx公司的 5 0万门级芯片XCV4 0 0E ,设计并实现CIF格式 ( 35 2× 2 88象素 )图像实时DCT变换 .该设计采用乒乓模式 ,只需设计一个快速算法模块 (F×CT)就解决了C×F×CT 的实现算法 .当视频信号通过数字化后逐行输入FPGA ,在行、场同步信号和采样时钟的控制下 ,每输入一组数据 ( 8个 ) ,就进行行向量与CT 的矩阵乘运算 (F×CT) ,并将结果按转置方式保存 ,每输入一个数进行一次 ( 1× 8)× ( 1× 8)矩阵运算 ,每行进行 35 2× ( 1× 8)× ( 8× 8)次矩阵运算 ,其中 4 4次 ( 1× 8)× ( 8× 8)矩阵运算的结果需要按转置形式 (HT=(F×CT) T)存储 ;当输入下一组 8行数据时 ,对该组数据进行与前述 8行数据相同的矩阵运算 ,而对刚做完 (F×CT)运算的 8行相应结果 ,则按正常顺序取出进行 (HT×CT)运算 ,将结果按转置形式 (GT=C×H)输出 .从而以实时流水的方式完成C×F×CT 运算 .功能仿真、时序仿真和与TMS32 0C6

Web服务组合功能与QoS的形式化统一建模和分析

进程代数是一种适合描述Web服务组合的形式建模语言,然而同样对QoS建模和分析的支持不足.在现有进程代数的基础上,提出了一种代价概率进程代数PPPA(priced probabilistic process algebra),给出其语法和语义,证明其具有功能、概率和代价的统一建模和分析能力.给出了基于PPPA统一建模和分析Web服务组合功能和QoS的方法.实例建模和分析了Web服务组合的功能、可靠性、性能和代价,其结果表明,PPPA可以有效地支持Web服务组合功能和QoS的形式化统一建模和分析.

基于进程代数的Web服务合成的替换分析

Web服务合成是Web服务研究领域的热点问题,Web服务的替换与Web服务合成密切相关且对于Web服务合成系统的健壮性有重要作用.使用进程代数作为形式化的工具描述Web服务,对合成中的行为特征进行推导,分析由于异步交互对Web服务合成设计与实现产生的影响.在此之上,基于服务合成正确性的定义,提出一种一致性关系,若新服务与将要被替换的参与合成的服务之间存在这种关系,那么替换后的服务合成仍然是正确的,并且替换是上下文无关的.

基于时间概率代价进程代数的Web服务组合建模和分析

形式化建模Web服务组合并分析其功能正确性和QoS可满足性,是提高组合服务可信性的重要手段,但目前形式化方法侧重功能正确性建模和分析,对QoS可满足性的建模和分析支持不足.为此提出一种时间概率代价进程代数TPPPA(Timed Probabilistic Priced Process Algebra),给出了TPPPA的语法和语义,并证明其具有功能、时间、概率和代价的统一建模和分析能力.用实例表明了TPPPA可有效支持Web服务组合功能正确性和QoS可满足性的形式化统一建模和分析.

基于连续小波变换的旋转机械振动信号灰度矩研究

通过对机械振动信号的连续小波变换 ,利用小波滤波器良好的时频特性 ,研究了振动信号连续小波变换灰度图的统计特征 ,提出了“一阶灰度矩向量”指标。对 8种典型故障信号的计算表明 ,一阶灰度矩向量可以较好地展现小波灰度图的局部信息 ,能够有效地提取信号的特征 ,区分振动故障。

可信计算平台信任链安全性分析

可信计算规范是指导可信计算产品研制的依据,可信计算规范本身的安全性需要得到验证.信任链是可信计算平台中保障系统安全可靠的主要技术手段,它是可信计算平台整个系统安全的中心问题.针对可信计算平台信任链规范的信息流安全问题,文中通过安全进程代数对信任链系统接口进行形式化建模,用可复合的不可演绎模型刻画信任链实体间的交互关系,把规范定义的信任链行为特性抽象为多级安全输入输出集,在讨论高级和低级输入输出依赖关系的基础之上,对信任链复合系统进行信息流分析,并给出结论和证明.