Stathatos, KonstantinosWith the immense popularity of the Web, the world is witnessing an unprecedented demand for online data services. A growing number of applications require timely data delivery frominformation producers to thousands of information consumers. At the same time, the Internetis evolving towards an information superhighway that incorporates a wide mixture of existingand emerging communication technologies, including wireless, mobile, and hybridnetworking. <p>For this new computing landscape, this thesis advocates creating highly scalable dataservices based on adaptive hybrid data delivery. It introduces air-caching, a technique thateffectively integrates broadcasting for massive dissemination of popular data, and unicastingfor upon-request delivery of the rest. It describes the special properties, performance goals,and challenges of air-caching. Then, it presents adaptive cache management techniques forthree different settings: servicing large numbers of data requests over heavily accessed databases, propagating data updates to mobile clients intermittently connected toinformation sources, and implementing publish/subscribe services again in the context ofmobile computing. In all cases, performance experiments demonstrate the scalability,efficiency, and versatility of this technique, even under rapidly changing data access patterns.en-USHybrid NetworksInternetWirelessAir-CachingIntelligent Signal Processing and Communications SystemsDissertation