Numerous systems for dissemination, retrieval, and archiving of documents have been developed in the past. Those systems often focus on one of these aspects and are hard to extend and combine. Typically, the transmission protocols, query and filtering languages are fixed as well as the interfaces to other systems. We rather envisage the seamless establishment of networks among the providers, repositories and consumers of information, supporting information retrieval and dissemination while being highly interoperable and extensible. We propose a framework with a single event-based mechanism that unifies document storage, retrieval, and dissemination. This framework offers complete openness with respect to document and metadata formats, transmission protocols, and filtering mechanisms. It specifies a high-level building kit, by which arbitrary processors for document streams can be incorporated to support the retrieval, transformation, aggregation and disaggregation of documents. Using the same kit, interfaces for different transmission protocols can be added easily to enable the communication with various information sources and information consumers.
@cite_12 is a push-model publish subscribe system for alerting within a wide-area network. It offers scalability by distributing filters over servers within the network and saving bandwidth by filtering close to the event sources and bundling similar subscriptions. Siena is modular and offers sophisticated filtering mechanisms including dynamic configuration and distribution. It lacks openness, document stream transformation, and scheduling.
@cite_12
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The publish subscribe (pub sub for short) paradigm is used to deliver events from a source to interested clients in an asynchronous way. Recently, extending a pub sub system in wireless networks has become a promising topic. However, most existing works focus on pub sub systems in infrastructured wireless networks. To adapt pub sub systems to mobile ad hoc networks, we propose DRIP, a dynamic Voronoi region-based pub sub protocol. In our design, the network is dynamically divided into several Voronoi regions after choosing proper nodes as broker nodes. Each broker node is used to collect subscriptions and detected events, as well as efficiently notify subscribers with matched events in its Voronoi region. Other nodes join their nearest broker nodes to submit subscriptions, publish events, and wait for notifications of their requested events. Broker nodes cooperate with each other for sharing subscriptions and useful events. Our proposal includes two major components: a Voronoi regions construction protocol, and a delivery mechanism that implements the pub sub paradigm. The effectiveness of DRIP is demonstrated through comprehensive simulation studies. Location-based services have become widely available on mobile devices. Existing methods employ a pull model or user-initiated model, where a user issues a query to a server which replies with location-aware answers. To provide users with instant replies, a push model or server-initiated model is becoming an inevitable computing model in the next-generation location-based services. In the push model, subscribers register spatio-textual subscriptions to capture their interests, and publishers post spatio-textual messages. This calls for a high-performance location-aware publish subscribe system to deliver publishers' messages to relevant subscribers.In this paper, we address the research challenges that arise in designing a location-aware publish subscribe system. We propose an rtree based index structure by integrating textual descriptions into rtree nodes. We devise efficient filtering algorithms and develop effective pruning techniques to improve filtering efficiency. Experimental results show that our method achieves high performance. For example, our method can filter 500 tweets in a second for 10 million registered subscriptions on a commodity computer. The components of a loosely coupled system are typically designed to operate by generating and responding to asynchronous events. An event notification service is an application-independent infrastructure that supports the construction of event-based systems, whereby generators of events publish event notifications to the infrastructure and consumers of events subscribe with the infrastructure to receive relevant notifications. The two primary services that should be provided to components by the infrastructure are notification selection (i.e., determining which notifications match which subscriptions) and notification delivery (i.e., routing matching notifications from publishers to subscribers). Numerous event notification services have been developed for local-area networks, generally based on a centralized server to select and deliver event notifications. Therefore, they suffer from an inherent inability to scale to wide-area networks, such as the Internet, where the number and physical distribution of the service’s clients can quickly overwhelm a centralized solution. The critical challenge in the setting of a wide-area network is to maximize the expressiveness in the selection mechanism without sacrificing scalability in the delivery mechanism. This paper presents SIENA, an event notification service that we have designed and implemented to exhibit both expressiveness and scalability. We describe the service’s interface to applications, the algorithms used by networks of servers to select and deliver event notifications, and the strategies used With the rapid progress of mobile Internet and the growing popularity of smartphones, location-aware publish subscribe systems have recently attracted significant attention. Different from traditional content-based publish subscribe, subscriptions registered by subscribers and messages published by publishers include both spatial information and textual descriptions, and messages should be delivered to relevant subscribers whose subscriptions have high relevancy to the messages. To evaluate the relevancy between spatio-textual messages and subscriptions, we should combine the spatial proximity and textual relevancy. Since subscribers have different preferences - some subscribers prefer messages with high spatial proximity and some subscribers pay more attention to messages with high textual relevancy, it calls for new location-aware publish subscribe techniques to meet various needs from different subscribers. In this paper, we allow subscribers to parameterize their subscriptions and study the location-aware publish subscribe problem on parameterized spatio-textual subscriptions. One big challenge is to achieve high performance. To meet this requirement, we propose a filter-verification framework to efficiently deliver messages to relevant subscribers. In the filter step, we devise effective filters to prune large numbers of irreverent results and obtain some candidates. In the verification step, we verify the candidates to generate the answers. We propose three effective filters by integrating prefix filtering and spatial pruning techniques. Experimental results show our method achieves higher performance and better quality than baseline approaches.