real-timecomputing is becoming an enabling technology for many important distributed applications such as flexible manufacturing, multimedia, robotics and process control. Traditionally, real-time systems have been r...
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ISBN:
(纸本)0818684321
real-timecomputing is becoming an enabling technology for many important distributed applications such as flexible manufacturing, multimedia, robotics and process control. Traditionally, real-time systems have been realized as isolated embedded systems. Unfortunately, this approach does nor longer suffice for future complex systems in the application scenarios mentioned above. In this situation, the use of an object-oriented design paradigm greatly reduces the complexity of the system while improving reusability and manageability. Furthermore, the surrounding IT-infrastructure is more a,ld more accessible through object-oriented interfaces (e.g. CORBA). In addition, object-oriented modeling allows reflecting the dynamic characteristics of the applications mentioned above by instantiating objects dynamically. In order to meet the real-time requirements in such an environment, static scheduling is not sufficient since many non-predictable resource conflicts influence execution times. Therefore, the most distinguishing requirement of these complex heterogeneous systems is the need of the computing system to dynamically adapt to dynamically changing conditions. Little work has been done on integrating object-oriented system design with resource allocation algorithms that are flexible enough to cope,vith this new requirement. This paper presents an approach for an adaptive object-oriented system with integrated monitoring, dynamic execution rime prediction and scheduling. It explains how this approach is applied to CORBA and C++.
This paper presents the Affected Set Priority Ceiling Protocols (ASPCP) for concurrency control in real-timeobject-oriented systems. These protocols are based on a combination of semantic locking and priority ceiling...
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ISBN:
(纸本)0818684321
This paper presents the Affected Set Priority Ceiling Protocols (ASPCP) for concurrency control in real-timeobject-oriented systems. These protocols are based on a combination of semantic locking and priority ceiling techniques. This paper shores that the ASPCP protocols provide higher potential concurrency for object-oriented systems than existing Priority Ceiling protocols, while still bounding priority inversion and preventing deadlock.
The ReTINA project (ACTS AC048) is an industrial collaboration to explore the use of CORBA for the support of real-time multimedia services, from the point of view of network control and from the point of view of midd...
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ISBN:
(纸本)0818684321
The ReTINA project (ACTS AC048) is an industrial collaboration to explore the use of CORBA for the support of real-time multimedia services, from the point of view of network control and from the point of view of middleware services. This paper covers CORBA for network control, and CORBA extensions towards a DPE framework for flexible binding and real-time support.
Many engineers are still reluctant to adopt advanced object-oriented technologies (such as high modularity: dynamic binding, automatic garbage collection, etc.) for embedded systems with real-time constraints, because...
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ISBN:
(纸本)0818684321
Many engineers are still reluctant to adopt advanced object-oriented technologies (such as high modularity: dynamic binding, automatic garbage collection, etc.) for embedded systems with real-time constraints, because of their supposed inefficiency. We set ourselves into the context of building telecommunication systems with a standard object-oriented analysis and design approach. We describe how we use relevant design patterns, followed with an implementation in a pure object-oriented language (Eiffel) to conciliate the needed efficiency with the benefits of the object-oriented approach - flexibility dynamic configurability maintenability portability, etc. We discuss a case study. based on the implementation of SMDS (Switched Multi-megabits Data Service) servers featuring high-throughput and low-delay transmissions and respecting the real-time constraints of SMDS.
The confluence of computers, communications, and databases is quickly creating a global virtual database where many applications require real-time access to both temporally accurate and multimedia data. This is partic...
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ISBN:
(纸本)0818684321
The confluence of computers, communications, and databases is quickly creating a global virtual database where many applications require real-time access to both temporally accurate and multimedia data. This is particularly true in military and intelligence applications, but these required features are needed in many commercial applications as well. We are developing a distributed database, called BeeHive, which could offer features along different types of requirements: real-time, fault-tolerance, security, and quality-of service for audio and video. Support of these features and potential trade-offs between them could provide a significant improvement in performance and functionality over current distributed database and object management systems. In this paper, we present a high level design for BeeHive architecture and sketch the design of the BeeHive object Model (BOM) which extends object-oriented data models by incorporating time and other features into objects.
One of the primary features of almost all physically distributed software is that it has to deal with the unpredictable nature and complexity of the physical world. For example, it has to detect failures and undertake...
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This paper reports on the issues in design and development of objectorientedreal-timedistributed Systems using Ada 95. The paper is broken into the following parts: First, one of the general distributedreal-time p...
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ISBN:
(纸本)0818684321
This paper reports on the issues in design and development of objectorientedreal-timedistributed Systems using Ada 95. The paper is broken into the following parts: First, one of the general distributedreal-time problems is introduced as it fits the domain within Boeing. Next, prototype solutions to the distributed capabilities are introduced including the new technologies present in Ada-95 through DSA (distributed Systems Annex-E)[2] and extended with CORBA (Common object Request Broker Architecture) capabilities[1]. Many issues are addressed with adoption and use of these technologies especially applicable as they relate to custom fine-tuned solutions used today to solve real-time constraints. As the various distributed solutions provide different strengths, a combination of the capabilities provides an attractive option. A hybrid distributed capability composed of DSA and CORBA has been developed and is discussed as it relates to the seamless introduction with the Ada language. Finally a set of research issues are raised.
Exception handling in a complex concurrent and distributed system (e.g. one involving cooperating rather than just competing activities) is often a necessary, but a very difficult, task. No widely accepted models or a...
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ISBN:
(纸本)0818684321
Exception handling in a complex concurrent and distributed system (e.g. one involving cooperating rather than just competing activities) is often a necessary, but a very difficult, task. No widely accepted models or approaches exist in this area. The object-oriented paradigm, for all its structuring benefits, and real-time requirements each add further difficulties to the design and implementation of exception handling in such systems. In this paper, we develop a general structuring framework based on the coordinated atomic (CA) action concept for handling exceptions in an object-orienteddistributed system, in which exceptions in both the value and the time domain are taken into account. In particular, we attempt to attack several difficult problems related to real-timetime system design and error recovery, including action-level timing constraints, time-triggered CA actions, and time-dependent exception handling. The proposed framework is then demonstrated and assessed using an industrial real-time application - the Production Cell III case study.
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.
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.
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