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Efficient information sharing is very important for emergency and rescue operations. Mobile Ad-Hoc Networks (MANETs) are often the only network environment for such operations. We have developed the MIDAS Data Space (MDS) to transparently share information among rescue applications in such environments. To achieve the required level of availability for important information, MDS performs optimistic replication. The problems caused by optimistic replication, like consistency management, are not solved by standard solutions; instead we employ tailor-made solutions for emergency and rescue applications.

In the Ad-Hoc InfoWare project, we develop a delay tolerant event notification service for sparse Mobile Ad-Hoc Networks for emergency and rescue operations. In most event notification solutions, subscriptions are formed with crisp values or crisp value ranges. Filtering mechanisms do not take into account more expressive subscriptions in terms of approximate predicates and complex aggregating relations among them. However, in emergency scenarios subscribers' interests often have gradual nature and subjective measure. Therefore, we design an intelligent event notification system allowing uncertainties to be modeled and complex matching semantics to be processed by fuzzy reasoning. Requiring more computational efforts, fuzzy logic introduces performance penalties in the whole network. We have developed a new subscription data structure and filtering algorithms, and evaluated and optimized it for runtime and space efficiency.

Information sharing is a mission critical key element in rescue and emergency operations. Mobile ad-hoc networks (MANETs) could provide a useful infrastructure to support information sharing, but appropriate applications are needed. To facilitate efficient application development for this type of infrastructure, middleware support is needed. In the Ad-Hoc Info Ware project, we are currently developing corresponding middleware services. In this paper, we discuss the application requirements that are imposed onto the middleware services, and we outline our technical approach to address the corresponding challenges. The architecture we propose comprises five main building blocks, namely knowledge management, a local and a distributed event notification service, resource management, and security and privacy management. We indicate design alternatives for these building blocks, identify open problems and relate our approach to the state-of-the-art.

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The subscription language is an important design decision for distributed event notification services (DENS). In order to minimize resource consumption and enable applications to use rich and complex subscription languages only when they are really needed, we have developed a DENS that separates the concerns of delivering subscriptions and notifications from the subscription specification and event filtering, i.e., the subscription language. To resolve the conflict between subscription language independence in DENS and a strict decoupling of publishers and subscribers through the DENS, we request that for each new subscription language three language specific plug-ins are provided. In this paper, we present the technical details of this solution and describe our proof-of-concept implementation that supports a simple attribute-value based subscription language and a fuzzy concept-based language.

Information sharing in dynamic mobile ad-hoc networks is a challenging task. High data availability in the presence of short and long term disconnections can be obtained by replicating shared data. The number of replicas must however be balanced against the cost of consistency management. In the MIDAS Data Space (MDS) we use optimistic replication together with internal versioning of data; this allows application-specific conflict resolution when reconciling replicas at network mergings. We have made a proof-of-concept implementation to perform experiments and to demonstrate through real-life field tests the usefulness of our design. In this paper we report our results. We have conducted a number of experiments on a small network formed by real devices to obtain a detailed performance evaluation. Using an emulation environment we have analysed and quantified the cost of consistency management, the impact of MDS operations, and the relationship between data availability and replication.

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