Pub Date : 1999-05-02DOI: 10.1109/ISORC.1999.776375
A. Polze, Jan Richling, J. Schwarz, M. Malek
The Common Object Request Broker Architecture (CORBA) is a widely-accepted, standardized open system integration framework based on distributed object technologies, which has been successfully used for implementation of open Web services. CORBA is focused on facilitating general computing environments and does not explicitly address quality-of-service parameters neither for its communication links nor its endsystems. However efforts like the Real-Time CORBA Special Interest Group (SIG) at OMG and the "pluggable protocols" proposal will ultimately lead to support of quality-of-service properties for CORBA communication links. We concentrate on architectural approaches for fault-tolerant, highly available endsystems. We present the Observer approach for implementation of reliable CORBA clients. Consensus protocols based on the Composite Objects technique is our solution for constructing CORBA servers with high predictability regarding timely and reliable method execution. Our middleware uses commercial off-the-shelf (COTS) technology and aims at conversion of legacy applications into reliable Web-services. We present Java-based Web-interfaces to the Balancing Robots soft real-time simulation. Also, we demonstrate a fault-tolerant version of the Netscape Navigator based on our Observer technique.
{"title":"Towards predictable CORBA-based Web-services","authors":"A. Polze, Jan Richling, J. Schwarz, M. Malek","doi":"10.1109/ISORC.1999.776375","DOIUrl":"https://doi.org/10.1109/ISORC.1999.776375","url":null,"abstract":"The Common Object Request Broker Architecture (CORBA) is a widely-accepted, standardized open system integration framework based on distributed object technologies, which has been successfully used for implementation of open Web services. CORBA is focused on facilitating general computing environments and does not explicitly address quality-of-service parameters neither for its communication links nor its endsystems. However efforts like the Real-Time CORBA Special Interest Group (SIG) at OMG and the \"pluggable protocols\" proposal will ultimately lead to support of quality-of-service properties for CORBA communication links. We concentrate on architectural approaches for fault-tolerant, highly available endsystems. We present the Observer approach for implementation of reliable CORBA clients. Consensus protocols based on the Composite Objects technique is our solution for constructing CORBA servers with high predictability regarding timely and reliable method execution. Our middleware uses commercial off-the-shelf (COTS) technology and aims at conversion of legacy applications into reliable Web-services. We present Java-based Web-interfaces to the Balancing Robots soft real-time simulation. Also, we demonstrate a fault-tolerant version of the Netscape Navigator based on our Observer technique.","PeriodicalId":211905,"journal":{"name":"Proceedings 2nd IEEE International Symposium on Object-Oriented Real-Time Distributed Computing (ISORC'99) (Cat. No.99-61702)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128044409","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 : 1999-05-02DOI: 10.1109/ISORC.1999.776402
A. Silberman, K. Sundaram, A. Stoyen
Task graphs have been used for the specification and analysis of real time systems for some time. We are currently developing a mobile code management system that uses such a representation for specification, analysis, and execution time scheduling, dispatch, and resource allocation decisions. We describe our three level limited hierarchical task graph model. We discuss graph topology, the use of task graphs for both specification and description, and planned software engineering tools that will take advantage of our model. We concentrate on the use of task graphs to model iteration, branching structures, optional execution, and parallelism within a function execution.
{"title":"The use of task graphs for modeling complex system behavior","authors":"A. Silberman, K. Sundaram, A. Stoyen","doi":"10.1109/ISORC.1999.776402","DOIUrl":"https://doi.org/10.1109/ISORC.1999.776402","url":null,"abstract":"Task graphs have been used for the specification and analysis of real time systems for some time. We are currently developing a mobile code management system that uses such a representation for specification, analysis, and execution time scheduling, dispatch, and resource allocation decisions. We describe our three level limited hierarchical task graph model. We discuss graph topology, the use of task graphs for both specification and description, and planned software engineering tools that will take advantage of our model. We concentrate on the use of task graphs to model iteration, branching structures, optional execution, and parallelism within a function execution.","PeriodicalId":211905,"journal":{"name":"Proceedings 2nd IEEE International Symposium on Object-Oriented Real-Time Distributed Computing (ISORC'99) (Cat. No.99-61702)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121045079","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 : 1999-05-02DOI: 10.1109/ISORC.1999.776343
R. Lemos, A. Romanovsky
A cooperative action (CO action) is a modelling abstraction for representing collaborative behaviour between objects at different phases of the software development. In this paper, the original definition of a cooperative object-oriented approach for software development is extended in order to include the description of exceptional behaviour. Unlike the traditional methods that usually deal with exceptions at the late design and implementation phases, the proposed approach emphasises the separation of treatments of application-related, design-related and implementation-related exceptions during the software life-cycle. The feasibility of the approach is demonstrated in terms of a benchmark case study.
{"title":"Exception handling in a cooperative object-oriented approach","authors":"R. Lemos, A. Romanovsky","doi":"10.1109/ISORC.1999.776343","DOIUrl":"https://doi.org/10.1109/ISORC.1999.776343","url":null,"abstract":"A cooperative action (CO action) is a modelling abstraction for representing collaborative behaviour between objects at different phases of the software development. In this paper, the original definition of a cooperative object-oriented approach for software development is extended in order to include the description of exceptional behaviour. Unlike the traditional methods that usually deal with exceptions at the late design and implementation phases, the proposed approach emphasises the separation of treatments of application-related, design-related and implementation-related exceptions during the software life-cycle. The feasibility of the approach is demonstrated in terms of a benchmark case study.","PeriodicalId":211905,"journal":{"name":"Proceedings 2nd IEEE International Symposium on Object-Oriented Real-Time Distributed Computing (ISORC'99) (Cat. No.99-61702)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131113190","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 : 1999-05-02DOI: 10.1109/ISORC.1999.776366
A. Flores, A. C. Nacul, L. Silva, J. Netto, C. Pereira, L. Bacellar
The paper presents a quantitative evaluation of the temporal behavior of object oriented programs implemented using different programming environments. The main focus of the evaluation is the real time properties and the overhead caused by each layer of the underlying communication architecture, in order to verify the suitability of those environments for developing distributed real time object oriented systems. In the current state of the work, Java/RMI running over Windows 95 and AO/C++ running over QNX OS are compared. An extension of the comparison to include DCOM/Windows95, DCOM/Windows NT and ObjecTime/Windows NT is under development.
{"title":"Quantitative evaluation of distributed object-oriented programming environments for real-time applications","authors":"A. Flores, A. C. Nacul, L. Silva, J. Netto, C. Pereira, L. Bacellar","doi":"10.1109/ISORC.1999.776366","DOIUrl":"https://doi.org/10.1109/ISORC.1999.776366","url":null,"abstract":"The paper presents a quantitative evaluation of the temporal behavior of object oriented programs implemented using different programming environments. The main focus of the evaluation is the real time properties and the overhead caused by each layer of the underlying communication architecture, in order to verify the suitability of those environments for developing distributed real time object oriented systems. In the current state of the work, Java/RMI running over Windows 95 and AO/C++ running over QNX OS are compared. An extension of the comparison to include DCOM/Windows95, DCOM/Windows NT and ObjecTime/Windows NT is under development.","PeriodicalId":211905,"journal":{"name":"Proceedings 2nd IEEE International Symposium on Object-Oriented Real-Time Distributed Computing (ISORC'99) (Cat. No.99-61702)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114916067","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 : 1999-05-02DOI: 10.1109/ISORC.1999.776390
P. Carrére, J. Hermant, G. L. Lann
Real time distributed applications based on object oriented technology raise many complex issues, most of them still open. We elaborate on the reasons why traditional paradigms, found adequate for tackling simple problems, cannot help in addressing these complex issues. A detailed illustration is given with a problem in modular avionics, which has been addressed by resorting to proof based system engineering, an emerging discipline aimed at coping with real world problems complexity. Drawing from our experience with partners in industry, we report on why such paradigms and technologies as object orientation, distributed transactions, distributed architectures, transactional monitors, can be contemplated for the construction of real time distributed systems, provided that appropriate online decision making algorithms and protocols are resorted to.
{"title":"In pursuit of correct paradigms for object-oriented real-time distributed systems","authors":"P. Carrére, J. Hermant, G. L. Lann","doi":"10.1109/ISORC.1999.776390","DOIUrl":"https://doi.org/10.1109/ISORC.1999.776390","url":null,"abstract":"Real time distributed applications based on object oriented technology raise many complex issues, most of them still open. We elaborate on the reasons why traditional paradigms, found adequate for tackling simple problems, cannot help in addressing these complex issues. A detailed illustration is given with a problem in modular avionics, which has been addressed by resorting to proof based system engineering, an emerging discipline aimed at coping with real world problems complexity. Drawing from our experience with partners in industry, we report on why such paradigms and technologies as object orientation, distributed transactions, distributed architectures, transactional monitors, can be contemplated for the construction of real time distributed systems, provided that appropriate online decision making algorithms and protocols are resorted to.","PeriodicalId":211905,"journal":{"name":"Proceedings 2nd IEEE International Symposium on Object-Oriented Real-Time Distributed Computing (ISORC'99) (Cat. No.99-61702)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122915074","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 : 1999-05-02DOI: 10.1109/ISORC.1999.776348
M. Mortazavi, J. Connell
Over the past few decades, a great deal of research has been devoted to the development of real-time components and systems. Examples include real-time operating systems, real-time schedulers, real-time object models and real-time object brokers. Nevertheless, efforts to build such large-scale systems have lagged behind, due to interoperability problems, programming paradigms which are difficult to use, an absence of a standard QoS specification language, a general lack of maturity in the software engineering processes involved, and logistic difficulties of building large-scale distributed, real-time systems within a reasonable expenditure of resources. This paper focuses on the initial phases of the QUITE (QUorum Integration, Testbed and Exploitation) project, a recent effort to build a large-scale, QoS-aware, real-time system based on the integration of research technologies that have received funding from the Quorum program of the Defense Advanced Research Project Agency (DARPA). It emphasizes the process aspects of the QUITE integration effort.
{"title":"A unified process for the integration of large-scale, distributed, object-oriented, real-time systems in layered architectures","authors":"M. Mortazavi, J. Connell","doi":"10.1109/ISORC.1999.776348","DOIUrl":"https://doi.org/10.1109/ISORC.1999.776348","url":null,"abstract":"Over the past few decades, a great deal of research has been devoted to the development of real-time components and systems. Examples include real-time operating systems, real-time schedulers, real-time object models and real-time object brokers. Nevertheless, efforts to build such large-scale systems have lagged behind, due to interoperability problems, programming paradigms which are difficult to use, an absence of a standard QoS specification language, a general lack of maturity in the software engineering processes involved, and logistic difficulties of building large-scale distributed, real-time systems within a reasonable expenditure of resources. This paper focuses on the initial phases of the QUITE (QUorum Integration, Testbed and Exploitation) project, a recent effort to build a large-scale, QoS-aware, real-time system based on the integration of research technologies that have received funding from the Quorum program of the Defense Advanced Research Project Agency (DARPA). It emphasizes the process aspects of the QUITE integration effort.","PeriodicalId":211905,"journal":{"name":"Proceedings 2nd IEEE International Symposium on Object-Oriented Real-Time Distributed Computing (ISORC'99) (Cat. No.99-61702)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134470782","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 : 1999-05-02DOI: 10.1109/ISORC.1999.776351
Kane Kim, Masaki Ishida, Juqiang Liu
The time-triggered message-triggered object (TMO) structuring scheme has been established to remove the limitation of conventional object structuring techniques in developing applications containing real time (RT) distributed computing components. It is a natural and syntactically small but semantically powerful extension of the object oriented design and implementation techniques which allows the system designer to abstractly and yet accurately specify timing characteristics of data and function components of high level distributed computing objects. It is a unified approach for design and implementation of both RT and non-RT distributed applications. A cost-effective way to support TMO-structured distributed RT programming is to build a TMO execution engine as a middleware running on well established commercial software/hardware platforms. We present an efficient middleware architecture named TMO Support Middleware (TMOSM) which can be easily adapted to many commercial-off-the-shelf (COTS) platforms. The performance of a prototype implementation of TMOSM running on Windows NT platforms is also discussed.
{"title":"An efficient middleware architecture supporting time-triggered message-triggered objects and an NT-based implementation","authors":"Kane Kim, Masaki Ishida, Juqiang Liu","doi":"10.1109/ISORC.1999.776351","DOIUrl":"https://doi.org/10.1109/ISORC.1999.776351","url":null,"abstract":"The time-triggered message-triggered object (TMO) structuring scheme has been established to remove the limitation of conventional object structuring techniques in developing applications containing real time (RT) distributed computing components. It is a natural and syntactically small but semantically powerful extension of the object oriented design and implementation techniques which allows the system designer to abstractly and yet accurately specify timing characteristics of data and function components of high level distributed computing objects. It is a unified approach for design and implementation of both RT and non-RT distributed applications. A cost-effective way to support TMO-structured distributed RT programming is to build a TMO execution engine as a middleware running on well established commercial software/hardware platforms. We present an efficient middleware architecture named TMO Support Middleware (TMOSM) which can be easily adapted to many commercial-off-the-shelf (COTS) platforms. The performance of a prototype implementation of TMOSM running on Windows NT platforms is also discussed.","PeriodicalId":211905,"journal":{"name":"Proceedings 2nd IEEE International Symposium on Object-Oriented Real-Time Distributed Computing (ISORC'99) (Cat. No.99-61702)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122109197","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 : 1999-05-02DOI: 10.1109/ISORC.1999.776358
William Foote
The discipline of computer science has always featured a large gap between theory and practice. For example, both the object oriented paradigm and garbage collection techniques go back to at least the 1960s (H. Schorr and W. Waite, 1967; O.J. Dahl and K. Nygard, 1966) but they have only seen widespread commercial acceptance this decade. The Java/sup TM/ programming language has been an important factor leading to the commercial popularization of these techniques. The field of real time computing has suffered from a particularly acute disconnect between theory and practice. Java/sup TM/ technology can be applied to the building of real time systems through a set of standard extensions to the Java/sup TM/ platform. A set of extensions that bring the core benefits of the platform to real time will advance the commercial state of the art. It will help to narrow the gap between theory and practice. The paper explores different aspects of computer systems theory as applied to real time systems. It analyzes whether they are ready to be reduced to practice and standardized.
{"title":"Theory versus practice in real-time computing with the Java/sup TM/ platform","authors":"William Foote","doi":"10.1109/ISORC.1999.776358","DOIUrl":"https://doi.org/10.1109/ISORC.1999.776358","url":null,"abstract":"The discipline of computer science has always featured a large gap between theory and practice. For example, both the object oriented paradigm and garbage collection techniques go back to at least the 1960s (H. Schorr and W. Waite, 1967; O.J. Dahl and K. Nygard, 1966) but they have only seen widespread commercial acceptance this decade. The Java/sup TM/ programming language has been an important factor leading to the commercial popularization of these techniques. The field of real time computing has suffered from a particularly acute disconnect between theory and practice. Java/sup TM/ technology can be applied to the building of real time systems through a set of standard extensions to the Java/sup TM/ platform. A set of extensions that bring the core benefits of the platform to real time will advance the commercial state of the art. It will help to narrow the gap between theory and practice. The paper explores different aspects of computer systems theory as applied to real time systems. It analyzes whether they are ready to be reduced to practice and standardized.","PeriodicalId":211905,"journal":{"name":"Proceedings 2nd IEEE International Symposium on Object-Oriented Real-Time Distributed Computing (ISORC'99) (Cat. No.99-61702)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121808400","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 : 1999-05-02DOI: 10.1109/ISORC.1999.776377
T. Kanezuka, H. Higaki, M. Takizawa
A multimedia object supports methods to manipulate the multimedia data in the object. A method changes not only the state of the object but also the QoS (quality of service) of the state. We discuss new equivalent and compatible relations among methods with respect to QoS. By using the relations, we discuss a QoS-based compensation method to undo the computation. We also discuss a locking scheme for objects.
{"title":"Quality-based compensation of multimedia objects","authors":"T. Kanezuka, H. Higaki, M. Takizawa","doi":"10.1109/ISORC.1999.776377","DOIUrl":"https://doi.org/10.1109/ISORC.1999.776377","url":null,"abstract":"A multimedia object supports methods to manipulate the multimedia data in the object. A method changes not only the state of the object but also the QoS (quality of service) of the state. We discuss new equivalent and compatible relations among methods with respect to QoS. By using the relations, we discuss a QoS-based compensation method to undo the computation. We also discuss a locking scheme for objects.","PeriodicalId":211905,"journal":{"name":"Proceedings 2nd IEEE International Symposium on Object-Oriented Real-Time Distributed Computing (ISORC'99) (Cat. No.99-61702)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121101692","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 : 1999-05-02DOI: 10.1109/ISORC.1999.776367
A. Bondavalli, I. Mura, I. Majzik
The paper deals with the automatic dependability analysis of systems designed using UML. An automatic transformation is defined for the generation of models to capture systems dependability attributes, like reliability. The transformation concentrates on structural UML views, available early in the design, to operate at different levels of refinement, and tries to capture only the information relevant for dependability to limit the size (state space) of the models. Due to the modular construction, these models can be refined later as more detailed, relevant information becomes available. Moreover a careful selection of those critical parts to be detailed allows one to avoid explosion of the size. An implementation of the transformation is in progress and will be integrated in the toolsets available for the ESPRIT LTR HIDE project.
{"title":"Automated dependability analysis of UML designs","authors":"A. Bondavalli, I. Mura, I. Majzik","doi":"10.1109/ISORC.1999.776367","DOIUrl":"https://doi.org/10.1109/ISORC.1999.776367","url":null,"abstract":"The paper deals with the automatic dependability analysis of systems designed using UML. An automatic transformation is defined for the generation of models to capture systems dependability attributes, like reliability. The transformation concentrates on structural UML views, available early in the design, to operate at different levels of refinement, and tries to capture only the information relevant for dependability to limit the size (state space) of the models. Due to the modular construction, these models can be refined later as more detailed, relevant information becomes available. Moreover a careful selection of those critical parts to be detailed allows one to avoid explosion of the size. An implementation of the transformation is in progress and will be integrated in the toolsets available for the ESPRIT LTR HIDE project.","PeriodicalId":211905,"journal":{"name":"Proceedings 2nd IEEE International Symposium on Object-Oriented Real-Time Distributed Computing (ISORC'99) (Cat. No.99-61702)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114791376","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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