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4th ieee international symposium on object-oriented real-time computing (ISORC 2001)

作者： Ip, MTW Lin, WWK Wong, AKY Dillon, TS Wang, DH Hong Kong Polytech Univ Dept Comp Kowloon Hong Kong Peoples R China

ISBN: (纸本)0769510892

In an ORC (object-oriented real-time computing) environment, it is important to reduce message retransmissions during message passing because these retransmissions cause significant time delay. And, this makes it difficult to achieve the necessary timeliness. A cause of retransmission is message loss due to buffer overflow at the reception side. Here a P+I+D (P for proportional, I for integral and D for derivative) adaptive buffer control algorithm is proposed to prevent such possible overflow. the I control depends on the Convergence Algorithm (CA), which is a stable and efficient IEPM (Internet End-to-End Performance Measurement) toot that predicts the mean message roundtrip time (RTT) of a communication channel quickly and accurately,. the P+I+D algorithm was tested under different conditions in a mobile ORC (MORC) environment, where mobile agents collaborate freely over the Internet. the different test results confirm that the proposed P+I+D approach is indeed effective for preventing buffer overflow.

关键词： MORC buffer overflow P plus I plus D control algorithm adaptive Convergence Algorithm

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Service differentiation in real-time main memory databases 5

Service differentiation in real-time main memory databases

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5th ieee international symposium on object-oriented real-time distributed computing (ISORC 2002)

作者： Kang, KD Son, SH Stankovic, JA Univ Virginia Dept Comp Sci Charlottesville VA 22903 USA

ISBN: (纸本)0769515584

the demand for real-time database services has been increasing recently. Examples include sensor data fusion, stock trading, decision support, web information services, and data-intensive smart spaces. In these systems, it is essential to execute transactions in time using fresh (temporally consistent) data. Due to the high service demand, many transactions may miss their deadlines regardless of their importance. To address the problem, we present a service differentiation architecture for real-time databases. Transactions are classified into several service classes based on their importance. Under overload, different degrees of deadline miss ratio guarantees are provided among the service classes according to their importance. A certain data freshness guarantee is also provided for the data accessed by timely transactions which finish within their deadlines. Feedback control is applied to support the miss ratio and freshness guarantees. In a simulation study, our service differentiation approach shows a significant performance improvement compared to the baseline approaches. the specified miss ratio and freshness are supported even in the presence of unpredictable workloads and data access patterns.

关键词： Computer science Electronic switching systems Feedback control Intelligent sensors object oriented modeling Process control Remote monitoring Sensor fusion Timing Transaction databases

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Non-functional information transmission patterns for distributed real-time Java

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SOFTWARE-PRACTICE & EXPERIENCE 2011年第12期41卷 1409-1435页

作者： Basanta-Val, P. Garcia-Valls, M. Estevez-Ayres, I. Univ Carlos III Madrid DREQUIEM Lab Madrid Spain

Many real-time systems use preemptive priority-based scheduling in their internals to guarantee certain real-time performance. this includes technologies that range from the real-time Specification for Java (RTSJ) to middleware like real-time Common object Request Broker Architecture (RT-CORBA), which offers additional models and policies that blend client and server information. this decision eases the integration of real-time admission tests and dispatching policies in these types of infrastructures. In this paper, we analyze different trade-offs that emerge from the definition of different propagation models for distributed real-time Java. the paper covers technological integration aspects as impact on interfaces and other practical issues mainly related to the performance that this model offers to a real-time application and non-functional overhead. the contribution described in the paper may help in the development of the distributed Specification for Java (DRTSJ). Copyright (C) 2011 John Wiley & Sons, Ltd.

关键词： RTSJ DRSTJ RT-JRMP RT-RMI

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RTM-TECS: Collaboration Framework for Robot Technology Middleware and Embedded component System 19

RTM-TECS: Collaboration Framework for Robot Technology Middl...

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19th ieee international symposium on real-time distributed computing (ISORC)

作者： Hasegawa, Ryo Yawata, Naofumi Ando, Noriaki Nishio, Nobuhiko Azumi, Takuya Osaka Univ Grad Sch Engn Sci Suita Osaka 565 Japan Ritsumeikan Univ Grad Sch Informat Sci & Engn Kyoto Japan Natl Inst Ind Sci & Technol AIST Tokyo Japan

ISBN: (纸本)9781467390323

Robot technologies, such as robot technology middleware (RTM) that is a component-oriented platform, are popular. However, RTM does not ensure stable real-time processing in common object request broker architecture. In this paper, a collaboration framework of RTM and TOPPERS embedded component system (TECS) is proposed to address this problem. TECS, a system that satisfies real-time processing requirements, is employed to enhance real-time processing in the proposed framework. To implement the collaboration of RTM and TECS, we have adopted remote procedure call and one-way communication. In addition, extending a generator enables the generation of robot technology components from TECS components. We have evaluated the processor cycle counts of the proposed framework in comparison with those of a conventional method. In addition, we evaluated the execution time of serial communication and a motor application using the proposed framework. the evaluation results show that the proposed framework is functionally employed in a hard real-time system. Furthermore, we evaluated the amount of code generated by the proposed framework. the evaluation results reveal that the code generated by the proposed framework is reusable and can enhance productivity.

关键词： Middleware

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Developing a triggering system for real-time databases in distributed environment 4

Developing a triggering system for real-time databases in di...

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4th ieee international symposium on object-oriented real-time computing (ISORC 2001)

作者： Yoon, HS Han, H Kim, YK Jin, SI Chungnam Natl Univ Dept Comp Sci Taejon 305764 South Korea

ISBN: (纸本)0769510892

MMDB(Main Memory-resident DataBase) systems have been used for real-time applications, such as a stock market and an auction system, which require fast response time and predictable behavior. However, most existing MMDB systems do not support active functionalities. Also, the trigger capability which is specified in SQL3 and implemented in some conventional DBMSs provides only an extremely limited form of active functions. this paper proposes a scheme to add active capabilities to existing MMDB without modifying the kernel. Generally, active functions can be classified into event-triggered active functions, such as decision of buying or selling point according to the state of database, and time-triggered active functions, such as periodic updates of stock prices, which are frequently used in real-time applications. the proposed scheme is designed to provide both kinds of active functions for MMDB by putting a time manager which checks an absolute time for a time trigger and an SQL processing module which provides an event trigger.

关键词： Financial markets

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Hierarchical composition of parametric WCET in a component based approach

Hierarchical composition of parametric WCET in a component b...

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ieee international symposium on object, component, Service-oriented real-time distributed computing

作者： Leveque, thomas Borde, Etienne Marref, Amine Carlson, Jan Mälardalen Real-Time Research Centre Mälardalen University Sweden

ISBN: (纸本)9780769543680

Worst Case Execution time (WCET) computation is crucial to the overall timing analysis of real-time embedded systems. Facing the ever increasing complexity of such systems, techniques dedicated to WCET analysis can take advantage of component Based Software Engineering (CBSE) by decomposing a difficult problem into smaller pieces, easier to analyse. To achieve this objective, the corresponding analysis results have to be composed to provide timing guarantees on the whole system. In this paper, we express the WCET of a component as a formula, allowing to represent its different computational modes. We then propose a Model Driven Engineering (MDE) approach that derives parametric WCET for composite components from parametric WCET of their subcomponents. this approach gives more accurate WCET estimates than naaive additive compositional analysis by taking into account usage context of components. However, analysis scalability concerns lead us to consider a trade-off between precision and scalability. this trade-off can be specified in the model. the composition of WCET estimations is automated and produces the parametric WCET expression of the composite component under analysis. this approach has been integrated in PRIDE. © 2011 ieee.

关键词： Scalability

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Adaptive distributed service discovery for dependable service integration

Adaptive distributed service discovery for dependable servic...

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2010 13th ieee international symposium on object/component/Service-oriented real-time distributed computing Workshops, ISORC Workshops 2010

作者： Liu, Lu Xu, Jie Wu, Kaigui School of Engineering and Information Sciences Middlesex University London United Kingdom School of Computing University of Leeds Leeds United Kingdom College of Computer Science Chongqing University Chongqing China

ISBN: (纸本)9780769540382

For the provision of dependable search and rescue capability in dynamic and unpredictable disaster areas, each networked node should have ability to (1) autonomously support and co-operate with each other in a peer-to-peer (P2P) manner to quickly discover and dependably self-configure services available on the disaster area to deliver a real-time capability;(2) modify their behaviours to deliver a sustainable capability according to environmental changes;(3) self-organise themselves to generate higher flexibility and adaptability for disaster management systems;and (4) share information and generate access throughout the network. In this paper, we propose an Adaptive and Efficient Peer-to-peer Search (AEPS) approach for dependable service integration on service-oriented architecture based on a number of social behaviour patterns. AEPS is capable to efficiently discover desirable services for disaster monitoring and relief by interacting with connected nodes and to support dependable dynamic service integration in real time through coping with rapid and significant changes in the disaster area. AEPS has no single point of failure, providing greater dependability in provision of capability even in the worst case of failure of service registry. © 2010 ieee.

关键词： Information services

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Message from the symposium Co-Chairs

Message from the Symposium Co-Chairs

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international symposium on object-oriented real-time distributed computing

Presents the welcome message from the conference proceedings.

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A practical approach to secure web services

A practical approach to secure web services

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9th ieee international symposium on object and component-oriented real-time distributed computing

作者： Xu, Jie Yang, Erica Y. Bennett, Keith H. Univ Leeds Sch Comp Leeds LS2 9JT W Yorkshire England Univ Durham Sch Engn Durham DH1 3LE England

ISBN: (纸本)076952561X

Web services provide the potential to offer interoperability of distributed business-to-business application integration between autonomous organisations, regardless of platforms, operating systems or languages. For both user and vendor organisations, this raises immediate problems of trust, security, privacy and prevention of malicious attacks. Until these problems are addressed and solved properly, the use of Web services will be severely restricted because no-one will trust them. We describe in this paper a service-oriented architecture and an Attack-Tolerant Information Retrieval (ATIR) service which tackles certain classes of privacy problems. In particular, we address the problem of protecting a user against malicious attacks upon an information service when the user retrieves some information from the service. Although there have been many theoretical solutions to certain aspects of this problem, the results have yet to be adapted to real systems. We report our experience of integrating the ATIR service with Taverna, a popular workflow system used amongst the UK e-Science/Grid computing community to support secure information retrieval in the biology context. Performance studies show that the overhead of ATIR server-side processing is trivial (< 5%) in comparison with the total processing time of the integrated Taverna. Our experimental results also show that the major processing overhead is caused by the Taverna enactor operations which consume no less than 50% of the total processing time.

关键词： attack tolerance distributed information retrieval malicious attacks privacy protection Web services

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Self*:: A data-flow oriented component framework for pervasive dependability

Self*:: A data-flow oriented component framework for pervasi...

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8th ieee international Workshop on object-oriented real-time Dependable Systems (WORDS 2003)

作者： Fetzer, C Högstedt, K AT&T Labs Res Shannon Lab Florham Pk NJ 07932 USA

ISBN: (纸本)0769519296

Both the scale and the reach of computer systems and embedded devices have been expanding constantly over the last few decades. As computer systems become pervasive, their criticality increases because they become an even more integral part of the infrastructure upon which our society depends. Hence, pervasive systems are likely to become "society critical" and their dependable operation must be ensured. Since the number of computing nodes in a pervasive system will be much greater than in traditional dependable systems, the operating cost per node needs to become much lower therefore, more cost effective dependability mechanisms need to be deployed to achieve the desired degree of dependability at a given maximum operating cost. In this paper we explain the notion of pervasive dependability and outline some of the challenges we face in achieving pervasive dependability We then describe our component based data-flow oriented middleware that we use as a test bed to investigate how to address these challenges.

关键词： Operating costs

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