Asynchronous event-based communication facilitates loose coupling and eases the integration of autonomous, heterogeneous components into complex systems. Many middleware platforms for event-based communication follow ...
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ISBN:
(纸本)3540236627
Asynchronous event-based communication facilitates loose coupling and eases the integration of autonomous, heterogeneous components into complex systems. Many middleware platforms for event-based communication follow the publish/subscribe paradigm. Despite the usefulness of such systems, their programming support is currently limited. Usually, publish/subscribe systems only exhibit low-level programming abstractions to application developers. In this paper we investigate programming abstractions for content-based publish/subscribe middleware in object-oriented languages, how they can be integrated in applications, and their implications on middleware implementation. We focus on the definition of filters and their implementation, the handling of notifications and meta-data, and programming support for composite events. We have implemented the presented approach for our content-based publish/subscribe middleware REBECA.
Wireless sensor networks (WSNs) involving actuation are increasingly envisioned in a range of fields. For instance, there is considerable interest in leveraging off WSNs to improve safety in road tunnels [3]. Research...
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ISBN:
(纸本)9781595937636
Wireless sensor networks (WSNs) involving actuation are increasingly envisioned in a range of fields. For instance, there is considerable interest in leveraging off WSNs to improve safety in road tunnels [3]. Researchers are envisioning tunnels equipped with WSN nodes that gather physical readings (e.g., light), monitor the structural integrity of the tunnel, and sense the presence of vehicles to detect a possible traffic congestion. Based on sensed data, the system operates a variety of devices, such as ventilation fans inside the tunnel, and traffic lights at the entrances. For instance, when a sensor detects the presence of a fire in a sector, the fans in the same sector are activated, and the traffic lights are turned red to prevent further vehicles from entering the tunnel.
Networked embedded systems must be able to rapidly respond to all kinds of sensing events, even though they have numerous failure-prone nodes and limited energy and bandwidth resources. The design methodology and soft...
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Networked embedded systems must be able to rapidly respond to all kinds of sensing events, even though they have numerous failure-prone nodes and limited energy and bandwidth resources. The design methodology and software environment described here mediate, between the developer's mental model of physical phenomena and the distributed application.
We describe a compilation system for the concurrent programming language Program Composition Notation (PCN). This notation provides a single-assignment programming model that permits concurrent-programming concerns su...
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We describe a compilation system for the concurrent programming language Program Composition Notation (PCN). This notation provides a single-assignment programming model that permits concurrent-programming concerns such as decomposition, communication, synchronization, mapping, granularity, and load balancing to be addressed separately in a design. PCN is also extensible with programmer-defined operators, allowing common abstractions to be encapsulated and reused in different contexts. The compilation system incorporates a concurrent-transformation system that allows abstractions to be defined through concurrent source-to-source transformations;these convert programmer-defined operators into a core notation. Run-time system techniques allow the core notation to be compiled into a simple concurrent abstract machine which can be implemented in a portable fashion using a run-time library. The abstract machine provides a uniform treatment of single-assignment and mutable data structures, allowing data sharing between concurrent and sequential program segments and permitting integration of sequential C and Fortran code into concurrent programs. This compilation system forms part of a program development toolkit that operates on a wide variety of networked workstations, multicomputers, and shared-memory multiprocessors. The toolkit has been used both to develop substantial applications and to teach introductory concurrent-programming classes, including a freshman course at Caltech.
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