Abstract not found

Complex communication patterns often need to take into account the situation in which the information to be communicated is produced or consumed. Publish-subscribe, and particularly its content-based incarnation, is often used to convey this information by encoding the “context ” of the publisher into the published messages. In this paper we claim that this approach is limiting and inefficient and propose a context-aware publish-subscribe model of communication as a better alternative. We describe a protocol that implements such model in a distributed publish-subscribe middleware, and analyze how it performs w.r.t. traditional content-based routing. 1.

Most of currently available content-based publish-subscribe systems that were designed to operate in large scale, wired scenarios, build their routing infrastructure as a set of brokers connected in an acyclic network. The topology of such network is critical for the performance of the system. Depending on the traffic profile, the same topology may provide good performance or be very inefficient. Starting from this consideration, in this paper we first analyze this issue in detail, then we describe a distributed algorithm to address it, by adapting the topology of a content-based publish-subscribe routing network to the application demand.

www.elsevier.com/locate/pmc Are our homes ready for services? A domotic infrastructure based on the Web service stack

Content-based publish/subscribe is a powerful data dissemination paradigm that offers both scalability and flexibility. However, its nature of high expressiveness makes it difficult to analyze or predict the behavior of the system such as event delivery probability and end-to-end delivery delay, especially when deployed over unreliable, best-effort public networks. This paper proposes the analytical model that abstracts expressiveness nature of content-based publish/subscribe, along with uncertainty of underlying networks, in order to predict quality of service in terms of delivery probability and timeliness based on partial, imprecise statistical attributes of each component in the system. Furthermore, the paper leverages the proposed prediction algorithm to implements heuristic-based subscriber admission control algorithms to maximize system utility when the system cannot support all subscribers. The evaluation results yields good prediction accuracy and admission rates. I.

Existing content-based publish/subscribe systems are designed assuming that all matching publications are equally relevant to a subscription. As we cannot know in advance the distribution of publication content, the following two unwanted situations are highly possible: a subscriber either receives too many or only few publications. In this paper we present a new publish/subscribe model which is based on the sliding window computation model. Our model assumes that publications have different relevance to a subscription. In the model, a subscriber receives k most relevant publications published within a time window w, where k and w are parameters defined per each subscription. As a consequence, the arrival rate of incoming relevant publications per subscription is predefined, and does not depend on the publication

The advent of very large scale distributed applications in the form of peer-to-peer systems, introduced new problems caused by their intrinsic dynamic behavior (i.e., nodes continuously joining and leaving the system). Such problems inhibit the usage of techniques developed for quasi-static distributed systems. In this paper we analyze the behavior of a simple subscriptionflooding based algorithm for publish/subscribe in a highly dynamic environment. Specifically we define the problem of keeping a list of processes matching a given event (Event Distribution List) complete and accurate. We propose a simple variant of the subscription flooding approach, introducing expiration of subscriptions and their periodic refresh, and show how it can maintain accurate and complete EDLs in a dynamic distributed system. 1

model for continuous top-k processing over data streams

Abstract. The SIENA publish/subscribe system represents a prototypical design for a distributed event notification service implementing the content-based publish/subscribe communication paradigm. A clear shortcoming of SIENA is represented by its static configuration that must be managed and updated by human administrators every time one of its internal processes (brokers) needs to be added or repaired (e.g. due to a crash failure). This problem limits the applicability of SIENA in large complex critical infrastructures where self-adaptation and-configuration are crucial requirements. In this paper we propose HSIENA, a hybrid architecture that complements SIENA by adding the ability to self-reconfigure after broker additions and removals. The architecture has a novel design that mixes the classic SIENA’s distributed architecture with a highly available cloud-based storage service. 1