Pub Date : 1994-10-24DOI: 10.1109/WORDS.1994.518680
T. Ng, Vikram N. Patel
The paper describes the experience of designing and implementing failure detection and reporting in a large distributed real time system used for air traffic control (ATC). We believe that systematic analysis is needed to guide the failure detection design and track the large number of failures that it deals with. Analysis such as how fast failures have to be detected should be performed carefully to avoid redesigns later. A comprehensive analysis also provides a basis for testing the design subsequently, during which fault injection and extended testing are needed to evaluate and debug the design. Failure detectors should detect specific failures so that appropriate reports and recovery actions can be initiated after detection.
{"title":"Timely failure detection in a large distributed real-time system","authors":"T. Ng, Vikram N. Patel","doi":"10.1109/WORDS.1994.518680","DOIUrl":"https://doi.org/10.1109/WORDS.1994.518680","url":null,"abstract":"The paper describes the experience of designing and implementing failure detection and reporting in a large distributed real time system used for air traffic control (ATC). We believe that systematic analysis is needed to guide the failure detection design and track the large number of failures that it deals with. Analysis such as how fast failures have to be detected should be performed carefully to avoid redesigns later. A comprehensive analysis also provides a basis for testing the design subsequently, during which fault injection and extended testing are needed to evaluate and debug the design. Failure detectors should detect specific failures so that appropriate reports and recovery actions can be initiated after detection.","PeriodicalId":446347,"journal":{"name":"Proceedings of Words '94. The First Workshop on Object-Oriented Real-Time Dependable Systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130806462","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 : 1994-10-24DOI: 10.1109/WORDS.1994.518666
Shi-Kuo Chang, Yeong-Jia Chen, D. Mossé
We present a modular approach to systematically introduce fault-tolerant properties into the design of time-dependent software components. The G-Net methodology for object-oriented complex software system design and the EU model for object-oriented dependable system design are integrated into the unified concept of the smart object, which is an object with an associated knowledge structure that incorporates the necessary parameters of the real-time task, such as the timing constraints and reliability requirements. Techniques to design resilient smart objects are described. These include fault tolerance guarantees and timing/performance/safety analysis.
{"title":"Smart objects for dependable real-time systems","authors":"Shi-Kuo Chang, Yeong-Jia Chen, D. Mossé","doi":"10.1109/WORDS.1994.518666","DOIUrl":"https://doi.org/10.1109/WORDS.1994.518666","url":null,"abstract":"We present a modular approach to systematically introduce fault-tolerant properties into the design of time-dependent software components. The G-Net methodology for object-oriented complex software system design and the EU model for object-oriented dependable system design are integrated into the unified concept of the smart object, which is an object with an associated knowledge structure that incorporates the necessary parameters of the real-time task, such as the timing constraints and reliability requirements. Techniques to design resilient smart objects are described. These include fault tolerance guarantees and timing/performance/safety analysis.","PeriodicalId":446347,"journal":{"name":"Proceedings of Words '94. The First Workshop on Object-Oriented Real-Time Dependable Systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123054568","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 : 1994-10-24DOI: 10.1109/WORDS.1994.518670
D. Stewart, P. Khosla
The Chimera Methodology is a new software engineering paradigm which addresses the problem of developing dynamically reconfigurable and reusable real-time software. The foundation of the Chimera Methodology is the port-based object model of a reusable software component. The model is obtained by applying the port-automaton formal computational model to object-based design. Global state variable table real-time communication is used to integrate port-based objects, which eliminates the need for writing and debugging glue code. The Chimera real-time operating system provides tools to support the software models defined by the Chimera Methodology, so that real-time software can be executed predictably using common real-time scheduling algorithms. A hypermedia user interface has been designed to allow users to easily assemble the real-time software components that are designed based on the Chimera Methodology. Use of the methodology can result in a significant decrease the development time and cost of real-time applications.
{"title":"The Chimera Methodology: designing dynamically reconfigurable real-time software using port-based objects","authors":"D. Stewart, P. Khosla","doi":"10.1109/WORDS.1994.518670","DOIUrl":"https://doi.org/10.1109/WORDS.1994.518670","url":null,"abstract":"The Chimera Methodology is a new software engineering paradigm which addresses the problem of developing dynamically reconfigurable and reusable real-time software. The foundation of the Chimera Methodology is the port-based object model of a reusable software component. The model is obtained by applying the port-automaton formal computational model to object-based design. Global state variable table real-time communication is used to integrate port-based objects, which eliminates the need for writing and debugging glue code. The Chimera real-time operating system provides tools to support the software models defined by the Chimera Methodology, so that real-time software can be executed predictably using common real-time scheduling algorithms. A hypermedia user interface has been designed to allow users to easily assemble the real-time software components that are designed based on the Chimera Methodology. Use of the methodology can result in a significant decrease the development time and cost of real-time applications.","PeriodicalId":446347,"journal":{"name":"Proceedings of Words '94. The First Workshop on Object-Oriented Real-Time Dependable Systems","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129527517","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 : 1994-10-24DOI: 10.1109/WORDS.1994.518672
E. Knightly, R. Mines, Hui Zhang
In this paper, we investigate several distributed real-time applications. The applications are real-time in that they require per-connection end-to-end performance bounds. These bounds, in terms of throughput, delay, and delay-jitter, are provided by the network via two mechanisms: admission control to limit access to the network and priority scheduling to enforce the guarantees. Within this framework, we perform a deterministic analysis on the applications and investigate, via the admission control criteria, the resulting utilization of the network. A deterministic analysis must analyze the worst-case properties of the sources in order to provide absolute bounds on throughput and delay. Three distributed real-time applications are analyzed in this paper: a video conferencing tool, a tool for combustion modeling using distributed computing, and an MPEG video archival system. Each has minimum performance requirements that must be provided by the network. By investigating these applications, we provide insights to the traffic characteristics and achievable network utilizations for practical real-time loads.
{"title":"Deterministic characterization and network utilizations for several distributed real-time applications","authors":"E. Knightly, R. Mines, Hui Zhang","doi":"10.1109/WORDS.1994.518672","DOIUrl":"https://doi.org/10.1109/WORDS.1994.518672","url":null,"abstract":"In this paper, we investigate several distributed real-time applications. The applications are real-time in that they require per-connection end-to-end performance bounds. These bounds, in terms of throughput, delay, and delay-jitter, are provided by the network via two mechanisms: admission control to limit access to the network and priority scheduling to enforce the guarantees. Within this framework, we perform a deterministic analysis on the applications and investigate, via the admission control criteria, the resulting utilization of the network. A deterministic analysis must analyze the worst-case properties of the sources in order to provide absolute bounds on throughput and delay. Three distributed real-time applications are analyzed in this paper: a video conferencing tool, a tool for combustion modeling using distributed computing, and an MPEG video archival system. Each has minimum performance requirements that must be provided by the network. By investigating these applications, we provide insights to the traffic characteristics and achievable network utilizations for practical real-time loads.","PeriodicalId":446347,"journal":{"name":"Proceedings of Words '94. The First Workshop on Object-Oriented Real-Time Dependable Systems","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122559759","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 : 1994-10-24DOI: 10.1109/WORDS.1994.518686
P. Gopinath, V. Thomas, M. Agrawal
This paper presents a variety of resource management techniques for real-time, fault-tolerant control systems. These techniques are based on resource scavenging, a concept that is introduced in this paper. Resource scavenging techniques attempt to meet transient resource shortfalls in one part of the system by reassigning resources from other parts of the system. The techniques presented take advantage of properties of real-time, fault-tolerant systems in general and some specific properties of control applications. At the same time, the techniques are constrained by control related requirements of the applications. The specific properties of a control application and its requirements are communicated to the system infrastructure entirely in terms of control concepts. Such a system infrastructure is also described in the paper. Finally, the paper proposes an extension to the programming language C++ that will simplify the development of applications that take advantage of resource scavenging techniques.
{"title":"Resource scavenging in object-oriented, real-time, fault-tolerant control systems","authors":"P. Gopinath, V. Thomas, M. Agrawal","doi":"10.1109/WORDS.1994.518686","DOIUrl":"https://doi.org/10.1109/WORDS.1994.518686","url":null,"abstract":"This paper presents a variety of resource management techniques for real-time, fault-tolerant control systems. These techniques are based on resource scavenging, a concept that is introduced in this paper. Resource scavenging techniques attempt to meet transient resource shortfalls in one part of the system by reassigning resources from other parts of the system. The techniques presented take advantage of properties of real-time, fault-tolerant systems in general and some specific properties of control applications. At the same time, the techniques are constrained by control related requirements of the applications. The specific properties of a control application and its requirements are communicated to the system infrastructure entirely in terms of control concepts. Such a system infrastructure is also described in the paper. Finally, the paper proposes an extension to the programming language C++ that will simplify the development of applications that take advantage of resource scavenging techniques.","PeriodicalId":446347,"journal":{"name":"Proceedings of Words '94. The First Workshop on Object-Oriented Real-Time Dependable Systems","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116869200","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 : 1994-10-24DOI: 10.1109/WORDS.1994.518685
J. Gustafsson
This paper describes the calculation of execution times in RealTimeTalk (RTT). RTT is an object-oriented language for hard real-time systems, i.e., systems which must fulfil the specified time requirements. An overview of RTT is given. The control structures in RTT are analysed and equations for the calculation of minimum and maximum execution times are given. The RTT timing analysis tools are described. The first tool is the front-end tool, which analyses the RTT code given by the user. The second is the back-end tool, which analyses the C-code and the assembly code in the RTT system. Some limitations of the method and future directions are discussed.
{"title":"Calculation of execution times in RealTimeTalk-an object-oriented language for real-time","authors":"J. Gustafsson","doi":"10.1109/WORDS.1994.518685","DOIUrl":"https://doi.org/10.1109/WORDS.1994.518685","url":null,"abstract":"This paper describes the calculation of execution times in RealTimeTalk (RTT). RTT is an object-oriented language for hard real-time systems, i.e., systems which must fulfil the specified time requirements. An overview of RTT is given. The control structures in RTT are analysed and equations for the calculation of minimum and maximum execution times are given. The RTT timing analysis tools are described. The first tool is the front-end tool, which analyses the RTT code given by the user. The second is the back-end tool, which analyses the C-code and the assembly code in the RTT system. Some limitations of the method and future directions are discussed.","PeriodicalId":446347,"journal":{"name":"Proceedings of Words '94. The First Workshop on Object-Oriented Real-Time Dependable Systems","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116098646","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 : 1994-10-24DOI: 10.1109/WORDS.1994.518669
K. Kim, L. Bacellar, Yuseok Kim, D. Choi, S. Howell, Michael Jenkins
In recent years, searching for a proper extension of the basic object model to meet the needs present in hard-real-time system development environments has become a serious research issue. The first co-author and Hermann Kopetz at the Technical University of Vienna formulated an extension of the basic object model, called the RTO.k object model, as one attempt to meet such needs. In the past two years, we have been making efforts to develop practical easy-to-use tools which assist the system engineers in (1) RTO.k structured description and simulation of application environments and (2) RTO.k structured hierarchical design of control computer systems. Unique features of the RTO.k model which distinguish it from other extensions of the basic object model as well as common features are presented. The roles which the RTO.k model can play during various steps of the real-time system engineering process are then discussed.
{"title":"Distinguishing features and potential roles of the RTO.k object model","authors":"K. Kim, L. Bacellar, Yuseok Kim, D. Choi, S. Howell, Michael Jenkins","doi":"10.1109/WORDS.1994.518669","DOIUrl":"https://doi.org/10.1109/WORDS.1994.518669","url":null,"abstract":"In recent years, searching for a proper extension of the basic object model to meet the needs present in hard-real-time system development environments has become a serious research issue. The first co-author and Hermann Kopetz at the Technical University of Vienna formulated an extension of the basic object model, called the RTO.k object model, as one attempt to meet such needs. In the past two years, we have been making efforts to develop practical easy-to-use tools which assist the system engineers in (1) RTO.k structured description and simulation of application environments and (2) RTO.k structured hierarchical design of control computer systems. Unique features of the RTO.k model which distinguish it from other extensions of the basic object model as well as common features are presented. The roles which the RTO.k model can play during various steps of the real-time system engineering process are then discussed.","PeriodicalId":446347,"journal":{"name":"Proceedings of Words '94. The First Workshop on Object-Oriented Real-Time Dependable Systems","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117119794","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 : 1994-10-24DOI: 10.1109/WORDS.1994.518681
Masahiko Saito, T. Yokoyama, Masaru Shimada
We present a method called Lazy Fault Tolerance for refining the reliability of distributed systems. Lazy Fault Tolerance uses data redundancy and the data of objects are distributed over computers in accordance with their 'nativity', The data of system management objects, which control the whole system based on the information of each computer, are naturally distributed over all computers. The object will restore its data by gathering all information from all computers in the case of failures. Lazy Fault Tolerance can greatly reduce the performance degradation in the absence of failures, although it takes a longer time to restore the system when a computer fails.
{"title":"Lazy fault tolerance-a method for dependable distributed systems","authors":"Masahiko Saito, T. Yokoyama, Masaru Shimada","doi":"10.1109/WORDS.1994.518681","DOIUrl":"https://doi.org/10.1109/WORDS.1994.518681","url":null,"abstract":"We present a method called Lazy Fault Tolerance for refining the reliability of distributed systems. Lazy Fault Tolerance uses data redundancy and the data of objects are distributed over computers in accordance with their 'nativity', The data of system management objects, which control the whole system based on the information of each computer, are naturally distributed over all computers. The object will restore its data by gathering all information from all computers in the case of failures. Lazy Fault Tolerance can greatly reduce the performance degradation in the absence of failures, although it takes a longer time to restore the system when a computer fails.","PeriodicalId":446347,"journal":{"name":"Proceedings of Words '94. The First Workshop on Object-Oriented Real-Time Dependable Systems","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132141269","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 : 1994-10-24DOI: 10.1109/WORDS.1994.518665
Warren H. Axtell
The paper describes the analysis and design of a time domain beamformer, using object modeling techniques, as a subset of a real-time sonar signal processing system. The goal is to illustrate the relationship of portability and reuse to object oriented analysis. This task is part of an initiative to foster the application of fast paced, emerging commercial technology to the development and acquisition of affordable strategic systems at the Naval Undersea Warfare Center (NUWC).
{"title":"A time domain beamformer object oriented analysis and design","authors":"Warren H. Axtell","doi":"10.1109/WORDS.1994.518665","DOIUrl":"https://doi.org/10.1109/WORDS.1994.518665","url":null,"abstract":"The paper describes the analysis and design of a time domain beamformer, using object modeling techniques, as a subset of a real-time sonar signal processing system. The goal is to illustrate the relationship of portability and reuse to object oriented analysis. This task is part of an initiative to foster the application of fast paced, emerging commercial technology to the development and acquisition of affordable strategic systems at the Naval Undersea Warfare Center (NUWC).","PeriodicalId":446347,"journal":{"name":"Proceedings of Words '94. The First Workshop on Object-Oriented Real-Time Dependable Systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126465900","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 : 1994-10-24DOI: 10.1109/WORDS.1994.518682
I. Yen, I. Chen, F. Bastani
We consider real time systems where multiple agents cooperate to jointly achieve the system goal. Further, the quality of the output of each agent has a fuzzy rather than a binary (pass/fail) value. The system model is defined and illustrated using examples from manufacturing and defense systems. Then, the reliability models for various types of service expectations are formulated and applied to a multiple agent coordination system.
{"title":"On the reliability of dependable soft real-time cooperating systems","authors":"I. Yen, I. Chen, F. Bastani","doi":"10.1109/WORDS.1994.518682","DOIUrl":"https://doi.org/10.1109/WORDS.1994.518682","url":null,"abstract":"We consider real time systems where multiple agents cooperate to jointly achieve the system goal. Further, the quality of the output of each agent has a fuzzy rather than a binary (pass/fail) value. The system model is defined and illustrated using examples from manufacturing and defense systems. Then, the reliability models for various types of service expectations are formulated and applied to a multiple agent coordination system.","PeriodicalId":446347,"journal":{"name":"Proceedings of Words '94. The First Workshop on Object-Oriented Real-Time Dependable Systems","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114345898","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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