A distributed alerting service for open digital library software

Alerting for Digital Libraries (DL) is an important and useful feature for the library users. To date, two independent services and a few publisher-hosted proprietary services have been developed. Here, we address the problem of integrating alerting as functionality into open source software for distributed digital libraries. DL software is one application out of many that constitute so-called meta-software: software where its installation determines the properties of the actual running system (here: the Digital Library system). For this type of application, existing alerting solutions are insufficient; new ways have to be found for supporting a fragmented network of distributed digital library servers. We propose the design and usage of a distributed Directory Service. This paper also introduces our hybrid approach using two networks and a combination of different distributed routing strategies for event filtering

Adopting Cloud Computing Technique for Efficient Event Forwarding Service To Users

Forwarding large volume of live content to relevant users in scalable efficient way in emergency application is main challenging task. One of the model named as the publisher and subscribe is used to forward the event service to users. but it fails to provide relevant event match services to subscribers another major problem is server fail .To handle this problem adopting cloud computing which provides complex computing and reliable communication. In this project proposing distributed overlay SkipCloud  to organize servers giving efficient scalable and reliable event matching services to subscribers. To partition the similar subscriptions in same server for each event hybrid multi-dimensional space partition technique is used. Finally proposed techniques shows efficiency in high matching event service and reduces the event forwarding delay

Efficient event routing in content-based publish/subscribe service network

Abstract—Efficient event delivery in a content-based publish/subscribe system has been a challenging problem. Existing group communication solutions, such as IP multicast or application-level multicast techniques, are not readily applicable due to the highly heterogeneous communication pattern in such systems. We first explore the design space of event routing strategies for content-based publish/subscribe systems. Two major existing approaches are studied: filter-based approach, which performs content-based filtering on intermediate routing servers to dynamically guide routing decisions, and multicastbased approach, which delivers events through a few high-quality multicast groups that are pre-constructed to approximately match user interests. These approaches have different trade-offs in the routing quality achieved and the implementation cost and system load generated. We then present a new routing scheme called Kyra that carefully balance these trade-offs. Kyra combines the advantages of content-based filtering and eventspace partitioning in the existing approaches to achieve better overall routing efficiency. We use detailed simulations to evaluate Kyra and compare it with existing approaches. The results demonstrate the effectiveness of Kyra in achieving high network efficiency, reducing implementation cost and balancing system load across the publish-subscribe service network. Keywords—System design, simulations, publish-subscribe, event notification I

General Boolean Expressions in Publish-Subscribe Systems

The increasing amount of electronically available information in society today is undeniable. Examples include the numbers of general web pages, scientific publications, and items in online auctions. From a user's perspective, this trend will lead to information overflow. Moreover, information publishers are compromised by this situation, as users have greater difficulty in identifying useful information. Publish-subscribe systems can be applied to cope with the reality of information overflow. In these systems, users specify their information interests as subscriptions and, subsequently, only matching information (event messages) is delivered; uninteresting information is filtered out before reaching users. In this dissertation, we consider content-based publish-subscribe systems, a sophisticated example of these systems. They perform the information-filtering task based on the content of provided information. In order to deal with high numbers of subscriptions and frequencies of event messages, publish-subscribe systems are realized as distributed systems. Advertisements---publisher specifications of potential future event messages---are optionally applied in these systems to reduce the internal distribution of subscriptions. Existing work on content-based publish-subscribe concepts mainly focuses on subscriptions and advertisements as pure conjunctive expressions. Therefore, subscriptions or advertisements using operators other than conjunction need to be canonically converted to disjunctive normal form by these systems. Each conjunctive component is then treated as individual subscription or advertisement. Unfortunately, the size of converted expressions is exponential in the worst case. In this dissertation, we show that the direct support of general Boolean subscriptions and advertisements improves the time and space efficiency of general-purpose content-based publish-subscribe systems. For this purpose, we develop suitable approaches for the filtering and routing of general Boolean expressions in these systems. Our approaches represent solutions to exactly those components of content-based publish-subscribe systems that currently restrict subscriptions and advertisements to conjunctive expressions. On the subscription side, we present an effective generic filtering algorithm, and a novel approach to optimize event routing tables, which we call subscription pruning. To support advertisements, we show how to calculate the overlap between subscriptions and advertisements, and introduce the first designated subscription routing optimization, which we refer to as advertisement pruning. We integrate these approaches into our prototype BoP (BOolean Publish-subscribe) which allows for the full support of general Boolean expressions in its filtering and routing components. In the evaluation part of this dissertation, we empirically analyze our prototypical implementation BoP and compare its algorithms to existing conjunctive solutions. We firstly show that our general-purpose Boolean filtering algorithm is more space- and time-efficient than a general-purpose conjunctive filtering algorithm. Secondly, we illustrate the effectiveness of the subscription pruning routing optimization and compare it to the existing covering optimization approach. Finally, we demonstrate the optimization effect of advertisement pruning while maintaining the existing overlapping relationships in the system