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Object databases such as db4o provide a very simple and effective way of making application objects persistent. However, they offer limited support for high-level database application programming in terms of facilities for the management of complex interrelated collections of data objects over long periods of time. Concepts of semantic data models such as role modelling, and associations are lacking and this results in a new impedance mismatch between the program and data models of the application. To address this problem, we have developed a semantic data management layer for db4o which supports role modelling, associations and a declarative query language.

Part 2: Autonomic and Distributed Network Management; International audience; Semantic caching is a technique used for optimizing the evaluation of database queries by caching results of old queries and using them when answering new queries. CoopSC is a cooperative database caching architecture, which extends the classic semantic caching approach by allowing clients to share their local caches in a cooperative matter. Thus, this approach decreases the response time of database queries and the amount of data sent by database server, because the server only answers those parts of queries that are not available in the cooperative cache. Since most cloud providers charge in a “pay-per-use” matter the amount of transferred data between the cloud environment and the outside world, using such a cooperative caching approach within cloud environmnents presents additional economical advantages. This paper studies possible use-cases of CoopSC within real-world cloud environment and outlines both the technical and economical gains.

Analyzing IP traffic is an important task on which many network management applications are based. Cisco's Net-Flow system is one of the most widely used approaches for accomplishing a measurement and collection of flow records, needed to analyze traffic. Working with NetFlow means to involve very large amounts of data, while the collection, storing, and enabling of analyzers demands the access to this data in the fastest possible manner. Thus, this paper addresses this challenging task and presents a newly developed cooperative caching approach (CoopSC) that can be used to improve access time and data transfers between the centralized flow-based storage solution and those analyzers in operation. Such an improvement can positively influence the performance of flow-based solutions. Therefore, this approach NMCoopSC (Network Management CoopSC) has been validated, and experiments show that NMCoopSC improves the performance of NetFlow-based range queries.

Semantic caching is a technique used for optimizing the evaluation of database queries by caching results of old queries and using them when answering new queries. CoopSC is a cooperative database caching approach, which extends the classic semantic caching approach by allowing clients to share their local caches in a cooperative matter. Cache entries of all clients are indexed in a distributed data structure constructed on top of a Peer-to-Peer (P2P) overlay network. This distributed index is used for determining those cache entries that can be used for answering a specific query. Thus, this approach decreases the response time of database queries and the amount of data sent by database server, because the server only answers those parts of queries that are not available in the cooperative cache. The approach has been validated and experiments show that CoopSC improves the performance of range queries.