Decreasing hardware costs is permitting the increased use of embedded computers to support complex and sophisticated applications in a variety of products. Many of these applications require computing nodes distribute...
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ISBN:
(纸本)0818684321
Decreasing hardware costs is permitting the increased use of embedded computers to support complex and sophisticated applications in a variety of products. Many of these applications require computing nodes distributed in different physical locations interconnected by communication networks. The object-oriented model with its well-known properties that facilitate the design of complex software applications is a natural choice for designing distributed embedded system applications. Existing models that support remote method invocation (RMI) in object-orienteddistributed computer systems are more tailored towards general distributed computer systems rather than embedded systems. Moreover, efficient implementations of these RMI models are rare at this time. In this paper, we analyze predominant RMI models with respect to essential features for embedded applications such as timeliness and fault handling capability. Based on this analysis. we propose the distributed dependable, distribution-transparent RMI model to support the execution of distributed embedded system applications.
Java-RMI is a well-known distribution middleware framework that allows the invocation of remote methods. This paper describes the extension of Java-RMI model to make the remote method calls time predictable. We identi...
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ISBN:
(纸本)0769510892
Java-RMI is a well-known distribution middleware framework that allows the invocation of remote methods. This paper describes the extension of Java-RMI model to make the remote method calls time predictable. We identify the problems of the jdk implementation of RMI and propose solutions to implement the Java-RMI extended model. This extended model and the proposed solutions are based on the Java and CORBA real-time extensions and especially on network resource reservation protocols. These extensions provide services for the network resources negotiation and to limit the latency of RMI services. The proposed solutions can be integrated in jdk1.2 RMI implementation, using the Java real-time package and RSVP implementations.
There is a trend towards using object-oriented-programming languages to develop hard real-time applications. However, some object-oriented-features, such as dynamic dispatching and dynamic loading, are prohibited from...
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ISBN:
(纸本)0769515584
There is a trend towards using object-oriented-programming languages to develop hard real-time applications. However, some object-oriented-features, such as dynamic dispatching and dynamic loading, are prohibited from being used in hard real-time systems because they are either unpredictable and/or unanalysable. Arguably, these restrictions could make applications very limited and unrealistic since they could eliminate the major advantages of object-oriented programming. This paper demonstrates how we can address the dynamic dispatching issues in Worst-Case Execution Timing (WCET) analysis with minimum annotations. The major contributions include: discussing the major issues involved in using and restricting dynamic binding features;weakening the restriction of using dynamic dispatching;presenting how to estimate tighter and safer WCET value in object-oriented hard real-time systems. Our approach shows that allowing the use of dynamic dispatching can not only provide a more flexible way to develop object-oriented hard real-time applications, but also does not necessarily result in unpredictable timing analysis.
In a real-timedistributedcomputing environment, security is critical to protect the system from unauthorized access especially since such systems are being used in time critical applications. Access Control mechanis...
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ISBN:
(纸本)076952561X
In a real-timedistributedcomputing environment, security is critical to protect the system from unauthorized access especially since such systems are being used in time critical applications. Access Control mechanisms have been introduced during the last several decades and have offered a basic and powerful means for enforcing security. In this paper, we examine the concepts of the TMO (time Triggered Message Triggered object) scheme that provides guaranteed real-time services in a distributedobjectcomputing environment. We also examine access control mechanisms;such as the traditional model, the RBAC (Role-based Access Control) model and the UCON (Usage Control) model. The main contribution of this paper is applying the traditional, RBAC and UCON models to the TMO scheme in order to provide a secure real-timedistributed environment.
This paper presents an object-oriented extension to the real-time programming language PEARL. The new language preserves PEARL's expressiveness for timeliness and industrial processes and, at same time, improves t...
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ISBN:
(纸本)0818684321
This paper presents an object-oriented extension to the real-time programming language PEARL. The new language preserves PEARL's expressiveness for timeliness and industrial processes and, at same time, improves the language's readability and manageability (through the better encapsulation paradigm derived from the object concept). Moreover the resulting object model allows the definition of inter and intra object parallelism in a transparent and simple way. Besides that, some extensions are also proposed to enhance testability and safety-related aspects of the language, such as the enforcement of a deterministic temporal behaviour.
The application of new technologies and programming tools represents a challenge and an economic risk for companies, which not all are prepared to assume. This paper presents the application of RT-CORBA in the develop...
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ISBN:
(纸本)076952124X
The application of new technologies and programming tools represents a challenge and an economic risk for companies, which not all are prepared to assume. This paper presents the application of RT-CORBA in the development of software for Nuclear Power Plant Simulators used for the training of future operators in a safe way. The developed software has allowed the adaptation of previous simulation software to new methodologies and standards;and the creation of new applications, aiming at the building of reusable components with real-time constraints in future projects.
real-time simulation is an advanced mode of simulation in which the simulator components are designed to show essentially the same timing behavior that the simulation targets do. distributedreal-time simulation is a ...
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ISBN:
(纸本)0769510892
real-time simulation is an advanced mode of simulation in which the simulator components are designed to show essentially the same timing behavior that the simulation targets do. distributedreal-time simulation is a field in its infancy but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributedtime-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-orientedreal-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributedreal-time simulation and major design principles and implementation techniques for resolving those issues within the DTS framework are presented. This technical foundation has been identified through multiple major DTS experiments conducted over the years. Some issues that require further research to realize the full potentials of the DTS scheme are also discussed.
Today, there is a rapidly growing interest to transfer object-oriented comparing technologies into various fields of control-critical applications. Existing approaches concentrate on abstract design-level modeling. In...
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ISBN:
(纸本)0818684321
Today, there is a rapidly growing interest to transfer object-oriented comparing technologies into various fields of control-critical applications. Existing approaches concentrate on abstract design-level modeling. In this paper we introduce "abstract object systems", an abstract mathematical model of concurrent real-timeobject systems. After that we present a simulation and analysis framework that takes into account implementation issues such as operation processing limits, scheduling strategies, processing priorities and distribution of threads to processors. The usual static class structuring relations are used. Messages exchanged between objects may be either synchronous method calls or asynchronous events. The details of object interaction are controlled by object-oriented state-charts. In addition, our framework deals with dynamic creation and deletion of objects and with distribution of treads onto multiple parallel processors.
ARTISST (ARTISST is a real-time System Simulation Tool) is a modular event-driven simulation framework for real-time systems. It is targeted towards the performance evaluation of complex dynamic real-time systems made...
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ISBN:
(纸本)0769515584
ARTISST (ARTISST is a real-time System Simulation Tool) is a modular event-driven simulation framework for real-time systems. It is targeted towards the performance evaluation of complex dynamic real-time systems made of tasks performing arbitrary computations and exhibiting a complex and realistic pattern for their arrival law, synchronization relations, and execution time. The simulator actually focuses on a time-accurate simulation, since it allows, among other things, to take the operating system (including its scheduler) costs into account. Furthermore, thanks to its modular and object-oriented software architecture, the simulator is not dedicated to a particular Operating System API, but is fully customizable instead. This paper describes ARTISST, and illustrates its functionalities and customization facilities on two example real-time systems.
For a long time embedded real-time systems have been designed as far as possible in a static manner. This means that they have been treated as pre-designed, off-line analysed, off-line mapped onto target systems, supp...
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ISBN:
(纸本)076952124X
For a long time embedded real-time systems have been designed as far as possible in a static manner. This means that they have been treated as pre-designed, off-line analysed, off-line mapped onto target systems, supported by customized but at run-time static real-time operating systems (RTOS), running on pre-assigned HW platforms. In this contribution some arguments for introducing more dynamics into real-time applications are given. Such dynamics finally may result in so called Autonomic Systems. When building autonomic real-time systems, specific support is needed. In this contribution some examples for such support are provided: Modelling techniques for distributed, self-modifying real-time systems, self modifying real-time operating systems, and usage self-modifying HW platforms.
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