The recent trend in distributed automation and control systems has been towards event-triggered system architectures such as UML and IEC 61499. Although existing communication protocols (e.g., Ethernet) can support hi...
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The recent trend in distributed automation and control systems has been towards event-triggered system architectures such as UML and IEC 61499. Although existing communication protocols (e.g., Ethernet) can support high-level communication within these systems, there is contention as to which low-level protocol to use, or if any exist that meet the requirements of being event-triggered and hard real-time. This paper proposes a new way to measure communication performance. The goal of the new measurement method is to stress the necessity that a real-time communication protocol needs to be both efficient and fair. This is illustrated by comparing three communication strategies: Controller Area Network (CAN), Time-Triggered CAN (TTCAN) and Escalating Priority CAN (EPCAN). The first two represent the extremes between event-triggered and time-triggered communication strategies;the third is introduced to illustrate the benefits of a new event-based communication protocol proposed by the authors. (c) 2010 Elsevier Ltd. All rights reserved.
This paper presents the development of an event-driven control architecture and its implementation in a physical simulator of a computerized manufacturing system using object-oriented techniques. The architecture was ...
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This paper presents the development of an event-driven control architecture and its implementation in a physical simulator of a computerized manufacturing system using object-oriented techniques. The architecture was developed to improve the efficiency of handling concurrent control events in the DOS environment. In the implementation, the control system of the physical simulator consists of four distinct layers of control devices: a PC/386 computer, a microcontroller, I/O modules and the system's control devices such as motors, solenoids and sensors. A control program residing in the PC/386 coordinates system-level tasks such as event scheduling, while a BASIC program running on the microcontroller handles all low-level control tasks such as sensor monitoring and motion control. The concepts and developments presented in this paper should help in implementing an efficient control system for both CIM systems and their physical simulators.
A key problem in compositional model checking of software systems is that typical model checkers accept only closed systems (runnable programs) and therefore a component cannot be model-checked directly. A typical sol...
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A key problem in compositional model checking of software systems is that typical model checkers accept only closed systems (runnable programs) and therefore a component cannot be model-checked directly. A typical solution is to create an artificial environment for the component such that its composition forms a runnable program that can be model-checked. Although it is possible to create a universal environment that performs all possible sequences and interleavings of calls of the component's methods, for practical purposes it is sufficient to capture in this way just the use of the component in a particular software system-this idea is expressed by the paradigm of assume-guarantee reasoning. The authors present an approach to assume-guarantee-based veri. cation of software systems in the context of the SOFA 2 component framework. They provide an overview of the approach to the construction of an artificial environment for the veri. cation of SOFA 2 components implemented in Java with the Java PathFinder model checker. They also show the benefits of their approach on results of experiments with a non-trivial software system and discuss its advantages over other approaches with similar goals.
This paper describes the application of an object-orientated framework for the control of manufacturing cells, The general principles of automated cell and robot control at the function and task levels are developed, ...
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This paper describes the application of an object-orientated framework for the control of manufacturing cells, The general principles of automated cell and robot control at the function and task levels are developed, and the appropriate modelling and programming concepts introduced, A multitasking control system for a specific automated cell for multilayer carbon fibre component manufacturing has been designed and developed using these principles, One feature of the work is the re-engineering of existing code so as to accommodate object-oriented principles, The resulting system is able to execute the manufacturing process safely and simultaneously on several parts of the same component, thus ensuring a high operating device utilization, The cell comprises two robots with specialized end effecters, a laser cutting table, a lay-up table and various inspection devices.
The large-scale computer simulation of a system of physical fields governed by partial differential equations requires some means of approximating the mathematical limit of continuity. For example, conservation laws a...
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The large-scale computer simulation of a system of physical fields governed by partial differential equations requires some means of approximating the mathematical limit of continuity. For example, conservation laws are often treated with a 'finite-volume' approach in which space is partitioned into a large number of small 'cells,' with fluxes through cell faces providing an intuitive discretization modeled on the mathematical definition of the divergence operator. Here we describe and make available Fortran 2003 classes furnishing extensible object-oriented implementations of simple meshes and the evolution of generic conserved currents thereon, along with individual 'unit test' programs and larger example problems demonstrating their use. These classes inaugurate the Mathematics division of our developing astrophysics simulation code GENASIS (General A strophysical Simulation System), which will be expanded over time to include additional meshing options, mathematical operations, solver types, and solver variations appropriate for many multiphysics applications. Program Summary Program Title: SineWave, SawtoothWave, RiemannProblem, RayleighTaylor, SedovTaylor, and FishboneMoncrief (fluid dynamics example problems illustrating GENASIS Mathematics) Program Files doi: http://***/10.17632/mzvxngwtw6.1 Licensing provisions: GPLv3 programming language: Fortran 2003 (tested with gfortran 6.2.0, Intel Fortran 16.0.3, Cray Compiler 8.5.3) External routines/libraries: MPI [1] and Silo [2] Nature of problem: By way of illustrating GENASIS Mathematics functionality, solve example 'fluid dynamics problems. Solution method: Finite-volume discretization;second-order slope-limited reconstruction;HLL Riemann Solver;Runge-Kutta time integration. Additional comments including Restrictions and Unusual features: The example problems named above are not ends in themselves, but serve to illustrate the functionality available though GENASIS Mathematics. In addition to these more su
An object-oriented numerical integration template implementation is presented on the basis of the C + + programming language. Aiming its straightforward application in finite and boundary element methods, the design s...
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An object-oriented numerical integration template implementation is presented on the basis of the C + + programming language. Aiming its straightforward application in finite and boundary element methods, the design supports integrand objects of scalar, vector or matrix types, so that a single programming statement is able to integrate element matrices and vectors. The integrand can contain singularities like the ones typically found in boundary element methods, allowing the evaluation of both regular and singular integrals under the same programming structure. The use of the proposed design is illustrated through sonic elementary applications as well as finite element and boundary element code excerpts. (C) 2005 Elsevier Ltd. All rights reserved.
Surgeons increasingly rely on dynamic, three-dimensional medical images for instrument guidance and clinical decision-making during minimally invasive procedures. The typical display combines images acquired before th...
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Surgeons increasingly rely on dynamic, three-dimensional medical images for instrument guidance and clinical decision-making during minimally invasive procedures. The typical display combines images acquired before the intervention with graphical representations of the instruments and also can include intraoperative image updates of the anatomy. Tracking systems indicate the location of surgical instruments relative to the patient's body, which helps guide the physician to the specific anatomical target. The authors' Image-Guided Software Toolkit contains the basic software components for developing an image-guided surgery system, including a component for controlling the tracker as well as a display component for overlaying images of patient anatomy and surgical instruments.
A data acquisition module, developed under a modular organizational architecture with links to an object-oriented design approach, is described. The module comprises four independent 250 MHz eight-bit data acquisition...
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A data acquisition module, developed under a modular organizational architecture with links to an object-oriented design approach, is described. The module comprises four independent 250 MHz eight-bit data acquisition channels and a DSP, each channel controlling a large memory pool for converted data and supporting several trigger and operating mechanisms. The hardware, although complex, is completely controlled through a set of hierarchically organized classes, making use of the object-oriented programming paradigm to keep complexity (from the user's and programmer's points of view) to a minimum. The integration of the module in the data acquisition system of the reflectometry diagnostic in tokamak ASDEX-Upgrade is described, showing the hardware in regular use and the validity of the object-oriented interface developed for programming.
Purpose - The purpose of this paper is to develop a computer aided decision-making model for flexible manufacturing system (FMS) situations when multiple conflicting objectives are addressed by the management. Design/...
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Purpose - The purpose of this paper is to develop a computer aided decision-making model for flexible manufacturing system (FMS) situations when multiple conflicting objectives are addressed by the management. Design/methodology/approach - It is assumed that the problem is the managerial level schedule rather than the operational schedule. As a tool, goal programming has been employed for measuring the trade-offs among the objectives. As a safeguard, the level of the reliability of the constraints associated with the random coefficients is taken into consideration. As an optimization technique, the approach of chance constrained programming which has been an operational way for introducing probabilistic constraints into the collection of the linear programming and goal programming problem constraints is stated and mathematically formulated. Findings - The approach of chance constrained programming is suitable to introduce management concerns about the reliability of the constraints of the problem in the FMS. Originality/value - The paper gives an overview of the FMS and proposes a goal programming model for the analysis of problem. The proposed model acknowledges the randomness of customer demands for better standardization of production planning and inventory management systems. By the fact that customer demands are not always deterministic the hypothesis that sale level for each period is normally distributed is imposed. A sample example problem is provided to show how the proposed model can work.
It is shown, in the context of an actual prototype VLSI CAD framework called Cbase, how concepts such as data abstraction, property and operation inheritance, object specialization/generalization, code reusability, an...
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It is shown, in the context of an actual prototype VLSI CAD framework called Cbase, how concepts such as data abstraction, property and operation inheritance, object specialization/generalization, code reusability, and polymorphism offered by object-oriented database management systems (OODBMSs) support rapid prototyping. The work was conducted on Vbase, a commercially available OODBMS, but the results and conclusions apply to any database with comparable capabilities. To implement the prototype user interface, the X11 toolkit, a windowing package that is also built around the object paradigm, was used
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