RTsynchronizer: language support for real-time specifications in distributed systems
LCTES '95 Proceedings of the ACM SIGPLAN 1995 workshop on Languages, compilers, & tools for real-time systems
A quality-of-service specification for multimedia presentations
Multimedia Systems - Special issue on multimedia database systems
A specification architecture for multimedia systems in open distributed processing
Computer Networks and ISDN Systems - Special issue: specification architecture
Formalizing multimedia QoS constraints using actors
FMOODS '97 Proceedings of the IFIP TC6 WG6.1 international workshop on Formal methods for open object-based distributed systems
Specifying real-time requirements for SDL specifications - a temporal logic-based approach
Proceedings of the Fifteenth IFIP WG6.1 International Symposium on Protocol Specification, Testing and Verification XV
A constraint-based approach for specification and verification of real-time systems
RTSS '97 Proceedings of the 18th IEEE Real-Time Systems Symposium
Quality of services specification in distributed object systems design
COOTS'98 Proceedings of the 4th conference on USENIX Conference on Object-Oriented Technologies and Systems - Volume 4
Customization of object request brokers by application specific policies
IFIP/ACM International Conference on Distributed systems platforms
Dependence Management in Component-Based Distributed Systems
IEEE Concurrency
Dynamic resource management and automatic configuration of distributed component systems
COOTS'01 Proceedings of the 6th conference on USENIX Conference on Object-Oriented Technologies and Systems - Volume 6
Stochastic dependability analysis of system architecture based on UML models
Architecting dependable systems
Using dynamic configuration to manage a scalable multimedia distribution system
Computer Communications
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Computing systems deliver their functionality at a certain level of performance, reliability, and security. We refer to such non-functional aspects as quality-of-service (QoS) aspects. Delivering a satisfactory level of QoS is very challenging for systems that operate in open, resource varying environments such as the Internet or corporate intranets. A system that operates in an open environment may rely on services that are deployed under the control of a different organization, and it cannot per se make assumptions about the QoS delivered by such services. Furthermore, since resources vary, a system cannot be built to operate with a fixed level of available resources. To deliver satisfactory QoS in the context of external services and varying resources, a system must be QoS aware so that it can communicate its QoS expectations to those external services, monitor actual QoS based on currently available resources, and adapt to changes in available resources. A QoS-aware system knows which level of QoS it needs from other services and which level of QoS it can provide. To build QoS-aware systems, we need a way to express QoS requirements and properties, and we need a way to communicate such expressions. In a realistic system, such expressions can become rather complex. For example, they typically contain constraints over user-defined domains where constraint satisfaction is determined relative to a user-defined ordering on the domain elements. To cope with this complexity we are developing a specification language and accompanying runtime representation for QoS expressions. This paper introduces our language but focuses on the runtime representation of QoS expressions. We show how to dynamically create new expressions at runtime and how to use comparison of expressions as a foundation for building higher-level QoS components such as QoS-based traders.