实时以太网控制系统的功能块执行方法

为了提高实时以太网控制系统的运行效率和通信性能,在EPA（Ethernet for Plant Automation）确定性通信调度的基础上提出了一种功能块执行方法。该方法将现场设备中所有需要远程通信的功能块整合为功能任务,并且按照功能块执行与数据通信周期同步的原理确定了功能任务的执行规律：功能任务在单个通信宏周期中只能单次执行,当周期报文空窗期满足功能任务执行需求时,功能任务在周期报文传输任务结束时执行;当周期报文空窗期不能满足功能任务执行需求时,功能任务在非周期报文传输任务结束时执行。实验证明,该方法实现了系统中功能任务与通信任务的周期同步,避免了功能块的无效执行与数据的无效传输,提高了系统的运行效率和通信性能。     

现场总线功能块组态策略软件设计与研究

现场总线控制系统是一种新型的自动化控制系统,文中首先介绍了现场总线功能块的含义及构成,采用VC++6.0为开发工具.编程实现各种通用的现场总线用户层功能块的功能;然后用VC++6.0采用文档/视类结构,图形化视图作为界面.文档负责组态数据的管理,模块以方块图显示,实现了可视化功能块组态策略图;最后以PID单回路控制系统为例介绍了功能块控制策略组态方法.     

FF现场总线控制系统功能块实例化的实现

在分析基金会现场总线功能块应用进程规范的基础上 ,提出了功能块实例化的实现方法 ,同时实现了功能块数据的保存和恢复 .该方法对基金会现场总线的工程应用和推广具有一定的意义 .     

基于EPA的PID功能块的设计及实现

本文介绍了EPA功能块基本模型及功能块定义并主要描述了PID功能块在单片机上的设计方案及PID功能块过程控制算法的具体实现,并通过组态软件验证了PID的过程控制算法及抗干扰的功能.     

XML与功能块相结合的设备描述方案

针对现有的设备描述方案的复杂性和不可通用性,研究了基于XML的设备描述语言和应用于现场自动化的以太网标准(EPA)功能块,提出一种将设备描述语言和功能块相结合的设备描述新方法。将不同厂商生产的EPA设备的属性分为几大类,其中的功能属性按照功能块的结构划分,使模拟功能块的描述与现场设备功能块的描述相对应,并将这种方法应用到了EPAConfiguration组态软件中,实现了功能块和设备描述对现场设备的综合描述,有利于设备的管理和控制。     

PLCopen多轴圆弧运动控制功能块的实现

针对目前市场上运动控制器编程语言不兼容、编程方法繁琐等问题,深入研究了基于PLCopen规范的功能块模型设计及圆弧插补算法的工作原理。首先,在试验室现有的"多轴运动控制器+μC/OS-Ⅲ"平台上,选用目前工控界广泛推广的德国3S公司的Codesys软件作为开发平台,以多轴圆弧运动控制功能块作为编程对象,采用结构化文本语言和顺序功能图,设计运动控制功能块。其次,通过在嵌入式系统中移植Codesys SP内核,使硬件平台成为符合IEC编程标准的可编程逻辑控制器,实现底层功能块的接口设计。最后,将设计好的功能块下载到控制器中,在Matlab中进行速度与位移曲线的仿真。仿真结果表明,功能块可达到设计要求,能够完成多轴运动,并可被移植到其他硬件平台上,具有很好的兼容性与复用性。     

基于FF的柔性功能块研究与开发

结合FF现场总线功能块技术和现场应用的实际情况，提出了柔性功能块形成的背景、功能和设计方案。给出了柔性功能块的实现原型。并举实例予以说明。     

DCS中顺序控制功能块应用及综合设计

在集散控制系统中,控制功能的实现是依靠控制功能块正确使用和控制回路图的正确连接.文中分析研究了常用的顺序控制功能块即定时器和计数器.对连续控制中选择开关SW-33与顺序控制的综合应用进行了设计分析.编写了顺序控制表.并对集散控制系统中应用实例进行了控制方案实现和运算块程序设计.     

DCS中顺序控制功能块应用及综合设计

在集散控制系统中,控制功能的实现是依靠控制功能块正确使用和控制回路图的正确连接。文中分析研究了常用的顺序控制功能块即定时器和计数器。对连续控制中选择开关SW-33与顺序控制的综合应用进行了设计分析。编写了顺序控制表。并对集散控制系统中应用实例进行了控制方案实现和运算块程序设计。     

语义信息与CRF结合的汉语功能块自动识别

为了构建汉语功能块自动识别系统,该文利用条件随机域模型对经过正确词语切分和词性标注处理的汉语句子进行功能块边界识别和功能信息标注处理,通过在特征提取阶段优化组合丰富的上下文特征,得到功能块识别的精确率、召回率和F1-measure值分别为85.84%、85.07%和85.45%。在此基础上,该文引入由词义聚合关系将汉语单词组织起来的《同义词词林》作为语义资源,把其中的语义信息作为特征加入到功能块的识别过程,缓解了数据稀疏以及歧义问题对识别结果造成的影响,使得上述三个性能指标分别提高到86.21%、85.31%和85.76%。     

Layout transformation support for the disk resident arrays framework

The Global Arrays (GA) toolkit provides a shared-memory programming model in which data locality is explicitly managed by the programmer. It inter-operates with MPI and supports a variety of language bindings. The Disk Resident Arrays (DRA) model extends the GA programming model to secondary storage. GA and DRA together provide a convenient programming model that encourages locality-aware programming by the user, while presenting a high-level abstraction. High performance depends on the appropriate distribution of the data in the disk-resident arrays. In this paper, we discuss the addition of layout transformation support to DRA. The implementation of an efficient parallel layout transformation algorithm is done on top of existing GA/DRA functions; thus GA/DRA is itself used in implementing the enhanced DRA functionality. Experimental performance data is provided that demonstrates the effectiveness of the new layout transformation functionality. This work was supported in part through funding from the U.S. Department of Energy and the National Science Foundation (award 0121676).     

A Fully Abstract Semantics for Concurrent Constraint Programming

A compositional and fully abstract semantics for concurrent constraint programming is developed. It is the first fully abstract semantics which takes into account both non-determinism, infinite computations, and fairness. We present a simple concurrent constraint programming language, whose semantics is given by a set of reduction rules augmented with fairness requirements. In the fully abstract semantics we consider two aspects of a trace, viz. the function computed by the trace (the functionality) and the set of input and output data (the limit of the trace). We then derive the fully abstract semantics from the set of traces using a closure operation. We give two proofs of full abstraction; the first relies on the use of a syntactically infinite context. The second proof requires only a finite context, but assumes as input a representation of the function to be computed by the context. Finally, we examine the algebraic properties of the programming language with respect to the fully abstract semantics. It turns out that the non-deterministic selection operation can be defined using operations derived from parallel composition and the usual set-theoretic operations on sets of traces.     

A constraint programming language for Life-Cycle Engineering

Life-Cycle Engineering is a design methodology that takes into account the mutually constraining influences of product manufacturability, testability and maintainability as well as functionality. We are using non-directional constraint networks to model these mutually constraining influences in order to enable product designers to design more successful products without sacrificing functionality. To do this, we have developed Leo, a constraint programming language whose features have been specifically chosen to support Life-Cycle Engineering. In this paper, we introduce Leo and show its operation in the domain of printed wiring board design.     

Non-programmers identifying functionality in unfamiliar code: strategies and barriers

Source code on the web is a widely available and potentially rich learning resource for non-programmers. However, unfamiliar code can be daunting to end-users without programming experience. This paper describes the results of an exploratory study in which we asked non-programmers to find and modify the code responsible for specific functionality within unfamiliar programs. We present two interacting models of how non-programmers approach this problem: the Task Process Model and the Landmark-Mapping model. Using these models, we describe code search strategies non-programmers employed and the barriers they encountered. Finally, we propose guidelines for future programming environments that support non-programmers in finding functionality in unfamiliar programs.     

Deriving guidelines for cross-vendor reuse of IEC 61131-3 modules based on Normalized Systems theorems

Flexibility, maintainability and evolvability are very desirable properties for modern automation control systems. In order to achieve these characteristics, modularity is regarded as an important concept in several scientific domains. The reuse of modules facilitates the reproduction of functionality, or extensions of existing systems in similar environments. However, it is often necessary to ‘prepare’ such an environment to be able to reuse the intended programmed functionality. In an IEC 61131-3 environment, cross-vendor reuse of modules is problematic due to dependencies in proprietary programming environments and existing configurations. In this paper, we aim to enable cross-vendor reuse of modules by controlling these dependencies. Our approach is based on the Normalized Systems Theory, from which we derived three guidelines for the design of reusable modules in an IEC 61131-3 environment for automation control projects. These guidelines are intended to support programmers in controlling dependencies, regardless of the commercial programming environment they work with.     

Alightweight class library for extended persistent object management in C++

When applications must keep their data structures persistent, additional effort beyond transient modeling is necessary to realize suitable persistent storage. The most convenient approach is the use of a persistent programming language (PPL), which offers internal mechanisms for storing and loading data transparently for the application programmer. An alternative to a PPL is a universal programming language that has been extended by persistence concepts for any data typesThis paper introduces an extended generic mechanism that abstracts necessary functionality for realizing persistence of any C++ object structure. First, we discuss general problems of persistent storage and the motivation for this approach. The design aspects and the reasons for special features are described in detail with the data and implementation insides. Finally, we sketch the persistent data structure and present the integration of the library in three different example programs.     

Interval arithmetic using expression templates, template meta programming and the upcoming C++ standard

In this paper we will discuss different realizations for an efficient interval arithmetic implementation using expression templates and template meta programming in C++. We will improve the handling of the rounding mode switches using expression templates and show how the constructed expression trees can be combined with other features like automatic differentiation. For a further improvement of the run time performance we try to move as many functionality as possible to the compile time using template meta programming techniques. In addition we will illustrate how an interval arithmetic implementation will profit from new features and keywords defined in the upcoming C++ standard.     

Automated user interface engineering with a pattern reflecting programming language

The development of the user interface concerns all aspects of a software system that are targeted to the interactive delivery of its functionality and data. Today, user interface development accounts for a large proportion of the overall software implementation, while the programming process involves various recurring software patterns. Based on the identification of key commonly occurring user interface programming patterns, we have designed and implemented a user interface programming language with built-in constructs to directly support those software patterns, offering declarative programming features such as: precondition-based actions, unidirectional constraints and data-content monitors. Initially, we introduce the deployment syntax and semantics of the novel programming elements, relying upon subject interaction scenarios. Then we reveal the most demanding implementation aspects of the code generator and the respective run-time library.     

Support vector machine classification with noisy data: a second order cone programming approach

In this paper, we investigate the stability of linear and quadratic programming support vector machines (SVMs) with bounded noise in the input data using a robust optimisation model. For a linear discriminant function, this model is expressed as a second order cone optimisation problem. Using the concept of the kernel function, we generalise for nonlinear discriminant functions. Intuitively, it looks quite clear that large margin classifiers are robust in terms of bounded input noise. However, there is no theoretical analysis investigating this behaviour. We show that the SVM solution is stable under bounded perturbations of the data both in the linear programming and quadratic programming. Computational results are also presented for toy and real-world data.     

Aspect‐oriented component assembly—a case study in parallel software design

In this paper we deal with building parallel programs based on sequential application code and generic components providing specific functionality for parallelization, like load balancing or fault tolerance. We describe an architectural approach employing aspect‐oriented programming to assemble arbitrary object‐oriented components. Several non‐trivial crosscutting concerns arising from parallelization are addressed in the light of different applications, which are representative of the most common types of parallelism. In particular, we demonstrate how aspect‐oriented techniques allow us to leave all existing code untouched. We evaluate and compare our approach with its counterparts in conventional object‐oriented programming. Copyright © 2008 John Wiley & Sons, Ltd.