Pub Date : 2003-10-01DOI: 10.1109/WORDS.2003.1267551
W. Steiner, M. Paulitsch, H. Kopetz
The Time-Triggered Architecture (TTA) is an architecture for safety-critical applications. Fault-tolerance mechanisms are therefor of upmost importance to ensure correct system operation in presence of failures as well as after transient disturbances. Currently the TTA tolerates one faulty component. Multiple transient failures are outside of the fault hypothesis of the TTA and scenarios can be established, after multiple transient failures, which cannot be corrected by the conventional TTA mechanism. Therefore, we propose an algorithm, for correction of the system after multiple transient failures, as an extension to the fault-tolerance mechanisms of the TTA. Furthermore, we discuss variations of this algorithm.
{"title":"Multiple Failure Correction in the Time-Triggered Architecture","authors":"W. Steiner, M. Paulitsch, H. Kopetz","doi":"10.1109/WORDS.2003.1267551","DOIUrl":"https://doi.org/10.1109/WORDS.2003.1267551","url":null,"abstract":"The Time-Triggered Architecture (TTA) is an architecture for safety-critical applications. Fault-tolerance mechanisms are therefor of upmost importance to ensure correct system operation in presence of failures as well as after transient disturbances. Currently the TTA tolerates one faulty component. Multiple transient failures are outside of the fault hypothesis of the TTA and scenarios can be established, after multiple transient failures, which cannot be corrected by the conventional TTA mechanism. Therefore, we propose an algorithm, for correction of the system after multiple transient failures, as an extension to the fault-tolerance mechanisms of the TTA. Furthermore, we discuss variations of this algorithm.","PeriodicalId":350761,"journal":{"name":"2003 The Ninth IEEE International Workshop on Object-Oriented Real-Time Dependable Systems","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115342653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-10-01DOI: 10.1109/WORDS.2003.1267500
Y. Hong, J. No
Fault-tolerant real-time multicast protocols are needed to develop fault-tolerant distributed real-time services such as group membership and redundancy management. In this paper, we propose the fault-tolerant real-time multicast protocol RFRM/X which is extended from RFRM. RFRM/X integrates clock synchronization module into the faulot manager by replacing heartbeat messages by clock synchronization messages. Thus, fault detection service is implemented without extra messages and with only a small overhead in the message size, quality of service is improved.
{"title":"A Fault-Tolerant Real-Time Multicast Protocol RFRM/X","authors":"Y. Hong, J. No","doi":"10.1109/WORDS.2003.1267500","DOIUrl":"https://doi.org/10.1109/WORDS.2003.1267500","url":null,"abstract":"Fault-tolerant real-time multicast protocols are needed to develop fault-tolerant distributed real-time services such as group membership and redundancy management. In this paper, we propose the fault-tolerant real-time multicast protocol RFRM/X which is extended from RFRM. RFRM/X integrates clock synchronization module into the faulot manager by replacing heartbeat messages by clock synchronization messages. Thus, fault detection service is implemented without extra messages and with only a small overhead in the message size, quality of service is improved.","PeriodicalId":350761,"journal":{"name":"2003 The Ninth IEEE International Workshop on Object-Oriented Real-Time Dependable Systems","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127556442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-10-01DOI: 10.1109/WORDS.2003.1267490
J. Gustafsson, B. Lisper, R. Kirner, P. Puschner
The execution time of software for hard real-time systems must be predictable. Further, safe and not overly pessimistic bounds for the worst-case execution time (WCET) must be computable. We conceived a programming strategy called WCET-oriented programming and a code transformation strategy, the single-path conversion, that aid programmers in producing code that meets these requirements. These strategies avoid respectively eliminate input-data dependencies in the code. The paper describes the formal analysis, based on abstract interpretation, that identifies input-data dependencies in the code and thus forms the basis for the strategies provided for hard real-time code development.
{"title":"Input-Dependency Analysis for Hard Real-Time Software","authors":"J. Gustafsson, B. Lisper, R. Kirner, P. Puschner","doi":"10.1109/WORDS.2003.1267490","DOIUrl":"https://doi.org/10.1109/WORDS.2003.1267490","url":null,"abstract":"The execution time of software for hard real-time systems must be predictable. Further, safe and not overly pessimistic bounds for the worst-case execution time (WCET) must be computable. We conceived a programming strategy called WCET-oriented programming and a code transformation strategy, the single-path conversion, that aid programmers in producing code that meets these requirements. These strategies avoid respectively eliminate input-data dependencies in the code. The paper describes the formal analysis, based on abstract interpretation, that identifies input-data dependencies in the code and thus forms the basis for the strategies provided for hard real-time code development.","PeriodicalId":350761,"journal":{"name":"2003 The Ninth IEEE International Workshop on Object-Oriented Real-Time Dependable Systems","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123351067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-10-01DOI: 10.1109/WORDS.2003.1267498
Frank Drews, L. Welch
This paper presents a model that is useful for developing resource allocation algorithms for distributed real-time systems that operate in dynamic environments. Interesting aspects of the model include dynamic environments, utility and service levels, which provide a means for graceful degradation in resource-constrained situations and support optimization of the allocation of resources. A software architecture of an adaptive resource manager is introduced and discussed.
{"title":"An Architecture and a General Optimization Framework for Resource Management in Dynamic, Distributed Real-Time Systems","authors":"Frank Drews, L. Welch","doi":"10.1109/WORDS.2003.1267498","DOIUrl":"https://doi.org/10.1109/WORDS.2003.1267498","url":null,"abstract":"This paper presents a model that is useful for developing resource allocation algorithms for distributed real-time systems that operate in dynamic environments. Interesting aspects of the model include dynamic environments, utility and service levels, which provide a means for graceful degradation in resource-constrained situations and support optimization of the allocation of resources. A software architecture of an adaptive resource manager is introduced and discussed.","PeriodicalId":350761,"journal":{"name":"2003 The Ninth IEEE International Workshop on Object-Oriented Real-Time Dependable Systems","volume":"77 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128595260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-10-01DOI: 10.1109/WORDS.2003.1267487
F. Rammig, C. Rust
In the paper a Petri net based approach for modeling dynamically modifiable embedded real-time systems is presented. The presented work contributes to the extension of a Petri net based design methodology for distributed embedded systems towards the handling of dynamically modifiable systems. Extensions to the underlying High-Level Petri net model are introduced that allow for dynamic modifications of a net at run-time. Furthermore, a simulation tool for the resulting self-modifying net model is outlined. The tool has been designed to simulate the execution of a dynamically modifying Petri net on a simplified model of a hardware platform which is dynamically modifying as well.
{"title":"Modeling of Dynamically Modifiable Embedded Real-Time Systems","authors":"F. Rammig, C. Rust","doi":"10.1109/WORDS.2003.1267487","DOIUrl":"https://doi.org/10.1109/WORDS.2003.1267487","url":null,"abstract":"In the paper a Petri net based approach for modeling dynamically modifiable embedded real-time systems is presented. The presented work contributes to the extension of a Petri net based design methodology for distributed embedded systems towards the handling of dynamically modifiable systems. Extensions to the underlying High-Level Petri net model are introduced that allow for dynamic modifications of a net at run-time. Furthermore, a simulation tool for the resulting self-modifying net model is outlined. The tool has been designed to simulate the execution of a dynamically modifying Petri net on a simplified model of a hardware platform which is dynamically modifying as well.","PeriodicalId":350761,"journal":{"name":"2003 The Ninth IEEE International Workshop on Object-Oriented Real-Time Dependable Systems","volume":"156 4-6","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114047238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-10-01DOI: 10.1109/WORDS.2003.1267496
Moon-hae Kim, E. Jo, Doohyun Kim
The goal of distributed multimedia applications is to provide reliable high-quality multimedia services to users on a network. Typical distributed multimedia applications use multimedia streaming that continuously processes and transports time-based media such as audio and video on a network. Inter-media synchronization and intra-media synchronization should be supported to facilitate high-quality reliable multimedia services. In this paper, we present an approach to develop distributed multimedia applications by using a real-time multimedia object model named MMStream TMO and a synchronization scheme for real-time streaming based on MMStream TMO and global time.
{"title":"Global Time-Based Synchronization of Real-Time Multimedia Streaming","authors":"Moon-hae Kim, E. Jo, Doohyun Kim","doi":"10.1109/WORDS.2003.1267496","DOIUrl":"https://doi.org/10.1109/WORDS.2003.1267496","url":null,"abstract":"The goal of distributed multimedia applications is to provide reliable high-quality multimedia services to users on a network. Typical distributed multimedia applications use multimedia streaming that continuously processes and transports time-based media such as audio and video on a network. Inter-media synchronization and intra-media synchronization should be supported to facilitate high-quality reliable multimedia services. In this paper, we present an approach to develop distributed multimedia applications by using a real-time multimedia object model named MMStream TMO and a synchronization scheme for real-time streaming based on MMStream TMO and global time.","PeriodicalId":350761,"journal":{"name":"2003 The Ninth IEEE International Workshop on Object-Oriented Real-Time Dependable Systems","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121286822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-10-01DOI: 10.1109/WORDS.2003.1267550
H. Schmidt, I. Peake, Jue Xie, Ian E. Thomas, B. Krämer, A. Fay, Peter Bort
Current models of component architectures require extensions to support compositional reasoning about extra-functional properties such as worst-case time. Studying such properties in architectures is complicated since actual components may not yet be chosen during architectural design, and different choices may have significant and hard to predict effects on the system properties. In this paper we show how finite state automata and Petri nets may be extended to provide compositionality of extra-functional properties. We focus on worst-case time and safety. We illustrate the use of these techniques on the well-known production cell case study. In collaboration with industry we are currently applying a prototype analysis system for predicting critical properties of real-time industrial control systems.
{"title":"Modelling Predictable Component-Based Distributed Control Architectures","authors":"H. Schmidt, I. Peake, Jue Xie, Ian E. Thomas, B. Krämer, A. Fay, Peter Bort","doi":"10.1109/WORDS.2003.1267550","DOIUrl":"https://doi.org/10.1109/WORDS.2003.1267550","url":null,"abstract":"Current models of component architectures require extensions to support compositional reasoning about extra-functional properties such as worst-case time. Studying such properties in architectures is complicated since actual components may not yet be chosen during architectural design, and different choices may have significant and hard to predict effects on the system properties. In this paper we show how finite state automata and Petri nets may be extended to provide compositionality of extra-functional properties. We focus on worst-case time and safety. We illustrate the use of these techniques on the well-known production cell case study. In collaboration with industry we are currently applying a prototype analysis system for predicting critical properties of real-time industrial control systems.","PeriodicalId":350761,"journal":{"name":"2003 The Ninth IEEE International Workshop on Object-Oriented Real-Time Dependable Systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130364818","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-10-01DOI: 10.1109/WORDS.2003.1267493
Haining Liu, M. Zarki
Due to the lack of QoS support, ensuring an acceptable application level QoS for the real-time delivery of multi-object multimedia presentations on the current Internet is very challenging. Currently, the only feasible solution is to artificially "equalize" the variable network delays. In this paper, we first investigate the application-level objective performance measures which reflect the user-perceived quality, and then propose an adaptive delay and synchronization control scheme making use of those metrics in real-time. The proposed scheme adopts a distributed timing model and can be configured with two inter-stream synchronization options based upon the application’s own characteristics. We take a wireline video conferencing application consisting of one audio stream and one video stream as an example. We detail the operation of the proposed scheme and investigate the resultant performance. The simulation results show that small synchronization phase distortions, low MDU loss percentages and low average end-to-end delays could be achieved simultaneously. We further discuss a more challenging issue raised by mobile wireless applications. A preliminery solution is proposed.
{"title":"Towards the Delay and Synchronization Control for Networked Real-Time Multi-Object Multimedia Applications","authors":"Haining Liu, M. Zarki","doi":"10.1109/WORDS.2003.1267493","DOIUrl":"https://doi.org/10.1109/WORDS.2003.1267493","url":null,"abstract":"Due to the lack of QoS support, ensuring an acceptable application level QoS for the real-time delivery of multi-object multimedia presentations on the current Internet is very challenging. Currently, the only feasible solution is to artificially \"equalize\" the variable network delays. In this paper, we first investigate the application-level objective performance measures which reflect the user-perceived quality, and then propose an adaptive delay and synchronization control scheme making use of those metrics in real-time. The proposed scheme adopts a distributed timing model and can be configured with two inter-stream synchronization options based upon the application’s own characteristics. We take a wireline video conferencing application consisting of one audio stream and one video stream as an example. We detail the operation of the proposed scheme and investigate the resultant performance. The simulation results show that small synchronization phase distortions, low MDU loss percentages and low average end-to-end delays could be achieved simultaneously. We further discuss a more challenging issue raised by mobile wireless applications. A preliminery solution is proposed.","PeriodicalId":350761,"journal":{"name":"2003 The Ninth IEEE International Workshop on Object-Oriented Real-Time Dependable Systems","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125247497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-10-01DOI: 10.1109/WORDS.2003.1267485
E. Jensen
This paper summarizes some of our unclassified work on concepts and techniques for performing automated run-time time-critical resource management (especially scheduling) in large scale, dynamic, control systems such as for battle management. The approach described here is based on application-level quality of service metrics, such as track quality and weapon spherical error probable. These metrics are used to derive parameters for thread time constraints in the form of time/utility functions. Threads are scheduled according to application-specific optimality criteria that seek to maximize accrued utility to the system. Two worked examples illustrate the cost-effectiveness of this approach for this class of application.
{"title":"Application QoS-Based Time-Critical Automated Resource Management in Battle Management Systems","authors":"E. Jensen","doi":"10.1109/WORDS.2003.1267485","DOIUrl":"https://doi.org/10.1109/WORDS.2003.1267485","url":null,"abstract":"This paper summarizes some of our unclassified work on concepts and techniques for performing automated run-time time-critical resource management (especially scheduling) in large scale, dynamic, control systems such as for battle management. The approach described here is based on application-level quality of service metrics, such as track quality and weapon spherical error probable. These metrics are used to derive parameters for thread time constraints in the form of time/utility functions. Threads are scheduled according to application-specific optimality criteria that seek to maximize accrued utility to the system. Two worked examples illustrate the cost-effectiveness of this approach for this class of application.","PeriodicalId":350761,"journal":{"name":"2003 The Ninth IEEE International Workshop on Object-Oriented Real-Time Dependable Systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129240944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-10-01DOI: 10.1109/WORDS.2003.1267536
IV RobertG.Pettit, H. Gomaa
Object-oriented software development practices are being rapidly adopted within increasingly complex systems, including real-time and concurrent system applications. To address reliability issues with designing software architectures for these concurrent, time-critical system, this paper outlines an approach for integrating formalisms with state-of-the-practice object-oriented models expressed in UML. In this approach, colored Petri nets (CPNs) are used as an underlying representation of the dynamic object-oriented architecture. These CPNs are then used to provide a simulated functional flow of the architecture and to analyze the concurrent behavior. By applying the results from the CPN analysis to the original UML model, an engineer can enhance the quality of the design and thereby improve the reliability of the resulting system.
{"title":"Improving the Reliability of Concurrent Object-Oriented Software Designs","authors":"IV RobertG.Pettit, H. Gomaa","doi":"10.1109/WORDS.2003.1267536","DOIUrl":"https://doi.org/10.1109/WORDS.2003.1267536","url":null,"abstract":"Object-oriented software development practices are being rapidly adopted within increasingly complex systems, including real-time and concurrent system applications. To address reliability issues with designing software architectures for these concurrent, time-critical system, this paper outlines an approach for integrating formalisms with state-of-the-practice object-oriented models expressed in UML. In this approach, colored Petri nets (CPNs) are used as an underlying representation of the dynamic object-oriented architecture. These CPNs are then used to provide a simulated functional flow of the architecture and to analyze the concurrent behavior. By applying the results from the CPN analysis to the original UML model, an engineer can enhance the quality of the design and thereby improve the reliability of the resulting system.","PeriodicalId":350761,"journal":{"name":"2003 The Ninth IEEE International Workshop on Object-Oriented Real-Time Dependable Systems","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129303873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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